The aim of this paper is to highlight the fact that students enter their higher education careers underprepared and fail their engineering studies due to the lack of various life skills. The South African Government i...The aim of this paper is to highlight the fact that students enter their higher education careers underprepared and fail their engineering studies due to the lack of various life skills. The South African Government is attempting to redress the social inequalities which prevailed in the education sector during the apartheid era. However, many students attempting their higher education studies are in many respects still under-prepared. This is mainly due to insufficient life skills, communication skills, numeric skills, and literacy skills. In the current study it was established, by means of a self-administered questionnaire, that students' lacking time of management skills, and study skills, are conditioned by their schooling not to value or use prescribed text books. These results re-emphasise the fact that students drop out of the programme for reasons other than academic performance and underline the need for effective measures toward student support and effective student learning.展开更多
BACKGROUND Foot drop causes considerable disability.The ankle-dorsiflexion is either weak or lost completely.Additionally,the ankle eversion and toe extensions are also impaired.This results in a high steppage gait wh...BACKGROUND Foot drop causes considerable disability.The ankle-dorsiflexion is either weak or lost completely.Additionally,the ankle eversion and toe extensions are also impaired.This results in a high steppage gait while walking.Overall,the gait is awkward;there is greater energy consumption;increased proneness to sustain injury of the forefoot;and more frequent falling during walking.AIM To document the clinical and epidemiological profile of foot drop patients in our population and evaluate the outcome of tibialis posterior(TP)tendon transfer for restoring the lost dorsiflexion in foot drop.METHODS The study was carried out at the National Institute of Rehabilitation Medicine in Islamabad over a period of 7 years.It included patients of all sexes and ages who presented with foot drop and had no contraindications for the procedure of TP tendon transfer.Exclusion criteria were patients who had contraindications for the operation.For instance,paralyzed posterior leg compartment muscles,Achilles tendon contracture,stiff ankle or toes,unstable ankle joint,weak gastrocnemius and scarred skin spanning over the route of planned tendon transfer.Also,patients who had the foot drop as a result of disc prolapses or brain diseases were excluded.Convenience sampling technique was used.The circum-tibial route of TP tendon transfer was employed.RESULTS Out of 37 patients,26(70.27%)were males whereas 11(29.72%)were females.The mean age was 22.59±8.19 years.Among the underlying causes of foot drop,road traffic accidents constituted the most common cause,found among 20(54.05%)patients.The share of complications included wound infections in 3(8.10%)patients and hypertrophic scars in 2(5.40%)patients.At 1-year postoperative follow-up visits,the outcome was excellent in 8(21.62%),good in 20(54.05%)and moderate in 9(24.31%).CONCLUSION The majority of cases of foot drop resulted from road traffic accidents that directly involved the common peroneal nerve.TP tendon transfer through the circumtibial route was found to be an easily executed effective operation which restored good dorsiflexion of the ankle among the majority of patients.展开更多
An artificial neural network(ANN)method is introduced to predict drop size in two kinds of pulsed columns with small-scale data sets.After training,the deviation between calculate and experimental results are 3.8%and ...An artificial neural network(ANN)method is introduced to predict drop size in two kinds of pulsed columns with small-scale data sets.After training,the deviation between calculate and experimental results are 3.8%and 9.3%,respectively.Through ANN model,the influence of interfacial tension and pulsation intensity on the droplet diameter has been developed.Droplet size gradually increases with the increase of interfacial tension,and decreases with the increase of pulse intensity.It can be seen that the accuracy of ANN model in predicting droplet size outside the training set range is reach the same level as the accuracy of correlation obtained based on experiments within this range.For two kinds of columns,the drop size prediction deviations of ANN model are 9.6%and 18.5%and the deviations in correlations are 11%and 15%.展开更多
Background: Cataract surgery is the most frequently performed surgery worldwide. Posterior capsule rupture (PCR) remains one of the most common complications of cataract surgery and a major risk factor for poor visual...Background: Cataract surgery is the most frequently performed surgery worldwide. Posterior capsule rupture (PCR) remains one of the most common complications of cataract surgery and a major risk factor for poor visual outcomes. Cataract surgeries complicated by PCR and vitreous loss are managed with anterior vitrectomy at the time of surgery. However, the situation can be further complicated by dropping lens particles into the vitreous cavity necessitating a secondary pars plana vitrectomy (PPV). Purpose: To compare the visual outcomes and risk of rhegmatogenous retinal detachment (RRD) between eyes that required anterior vitrectomy (AV) alone for the management of vitreous loss and eyes that required AV and subsequent PPV for the management of dropped nuclear lens fragments (DNLF) following cataract surgery complicated by PCR in a tertiary care teaching hospital in Saudi Arabia. Methods: Medical records of patients in whom PCR occurred during phacoemulsification cataract surgery requiring AV or subsequent PPV for DNLF were retrospectively reviewed over a 6-year period from January 2016 to December 2021. Results: PCR occurred in 183 (2.3%) of 7757 consecutive eyes that underwent phacoemulsification cataract surgery during the study period. Seven eyes were excluded from analysis for missing data or short follow-up. Of the 176 eyes, 147 eyes (83.5%) were managed with AV alone, and the remaining 29 eyes (16.5%) underwent a secondary PPV for DNLF. After excluding eyes with pre-existing ocular pathology, final best-corrected visual acuity (BCVA) was similar in both groups with a mean of 0.32 logMAR (P = 0.99). Two of 147 eyes (1.4%) in the AV group developed RRD with poor final BCVA whereas none of the eyes in DNLF group developed RRD. Conclusion: The risk of RRD is lower in eyes that required PPV for DNLF than in eyes that were managed with AV alone following PCR during cataract surgery. The poor visual outcomes in eyes that suffered RRD underscore the importance of postoperative retinal examination and early detection of retinal breaks.展开更多
The water-drop-shaped pressure hull has a good streamline,which has good application prospect in the underwater observatory.Therefore,this study conducted analytical,experimental and numerical investigation of the buc...The water-drop-shaped pressure hull has a good streamline,which has good application prospect in the underwater observatory.Therefore,this study conducted analytical,experimental and numerical investigation of the buckling properties of water-drop-shaped pressure hulls under hydrostatic pressure.A water-drop experiment was conducted to design water-drop-shaped pressure hulls with various shape indices.The critical loads for the water-drop-shaped pressure hulls were resolved by using Mushtari’s formula.Several numerical simulations including linear buckling analysis and nonlinear buckling analysis including eigenmode imperfections were performed.The results indicated that the critical loads resolved by Mushtari's formula were in good agreement with the linear buckling loads from the numerical simulations.This formula can be extended to estimate the buckling capacity of water-drop-shaped pressure hulls.In addition,three groups of pressure hulls were fabricated by using stereolithography,a rapid prototyping technique.Subsequently,three groups of the pressure hulls were subjected to ultrasonic measurements,optical scanning,hydrostatic testing and numerical analysis.The experimental results were consistent with the numerical results.The results indicate that the sharp end of the water-drop-shaped pressure hulls exhibited instability compared with the blunt end.This paper provides a new solution to the limitations of experimental studies on the water-drop-shaped pressure hulls as well as a new configuration and evaluation method for underwater observatories.展开更多
Accurate prediction of the frictional pressure drop is important for the design and operation of subsea oil and gas transporting system considering the length of the pipeline. The applicability of the correlations to ...Accurate prediction of the frictional pressure drop is important for the design and operation of subsea oil and gas transporting system considering the length of the pipeline. The applicability of the correlations to pipeline-riser flow needs evaluation since the flow condition in pipeline-riser is quite different from the original data where they were derived from. In the present study, a comprehensive evaluation of 24prevailing correlation in predicting frictional pressure drop is carried out based on experimentally measured data of air-water and air-oil two-phase flows in pipeline-riser. Experiments are performed in a system having different configuration of pipeline-riser with the inclination of the downcomer varied from-2°to-5°to investigated the effect of the elbow on the frictional pressure drop in the riser. The inlet gas velocity ranges from 0.03 to 6.2 m/s, and liquid velocity varies from 0.02 to 1.3 m/s. A total of885 experimental data points including 782 on air-water flows and 103 on air-oil flows are obtained and used to access the prediction ability of the correlations. Comparison of the predicted results with the measured data indicate that a majority of the investigated correlations under-predict the pressure drop on severe slugging. The result of this study highlights the requirement of new method considering the effect of pipe layout on the frictional pressure drop.展开更多
The voltage drop appearing at Mg anode-electrolyte interface is a critical issue for the battery power and energy density of aqueous primary Mg-air batteries.The respective voltage loss is typically assigned to the de...The voltage drop appearing at Mg anode-electrolyte interface is a critical issue for the battery power and energy density of aqueous primary Mg-air batteries.The respective voltage loss is typically assigned to the deposits layer forming on the anode surface during discharge.In this work,we experimentally and computationally investigate the critical factors affecting the voltage drop at Mg anode towards a deeper understanding of the contribution of deposit and its growth.A two-dimensional(2D)mathematical model is proposed to compute the voltage drop of Mg-0.15Ca wt.%alloy(Mg-0.15Ca)by means of a semi-empirical formulas and experiments-based modification model,considering the effect of discharge current density,the negative difference effect(NDE)and surface deposits layer itself.This model is utilized to simulate the discharge potential of the anode at predefined experimental current densities.The computed voltage drop(half-cell voltage)is in good agreement with the experimental value.The applicability of the mathematical model is successfully validated on the second material(namely high-purity Mg).展开更多
Currently,both regulated and deregulated power trading exist in China’s power system,which has caused imbalanced funds in the electricity market.In this paper,a simulation analysis of the electricity market with wind...Currently,both regulated and deregulated power trading exist in China’s power system,which has caused imbalanced funds in the electricity market.In this paper,a simulation analysis of the electricity market with wind energy resources is conducted,and the calculation methods of unbalanced funds are investigated systematically.In detail,the calculation formulas of unbalanced funds are illustrated based on their definition,and a two-track electricity market clearing model is established.Firstly,the concept of the dual-track system is explained,and the specific calculation formulas of various types of unbalanced funds are provided.Next,considering the renewable energy consumption,the market clearing model based on DC power flow is constructed and solved;by combining fitting methods of mid-and long-term curves,the unbalanced funds are calculated based on clearing results and formulas.展开更多
BACKGROUND Dry eye syndrome(DES)after diabetic cataract surgery can seriously affect the patient’s quality of life.Therefore,effective alleviation of symptoms in patients with this disease has important clinical sign...BACKGROUND Dry eye syndrome(DES)after diabetic cataract surgery can seriously affect the patient’s quality of life.Therefore,effective alleviation of symptoms in patients with this disease has important clinical significance.AIM To explore the clinical effect of recombinant human epidermal growth factor(rhEGF)plus sodium hyaluronate(SH)eye drops on DES after cataract surgery in patients with diabetes.METHODS We retrospectively evaluated 82 patients with diabetes who experienced DES after cataract surgery at Tianjin Beichen Hospital,Affiliated Hospital of Nankai University between April 2021 and April 2023.They were classified into an observation group(42 cases,rhEGF+SH eye drops)and a control group(40 cases,SH eye drops alone),depending on the different treatment schemes.The therapeutic efficacy,dry eye symptom score,tear film breakup time(TFBUT),basic tear secretion score[assessed using Schirmer I test(SIt)],corneal fluorescein staining(FL)score,tear inflammatory markers,adverse reactions during treat-ment,and treatment satisfaction were compared between the two groups.RESULTS Therapeutic efficacy was higher in the observation group compared with the control group.Both groups showed improved TFBUT and dry eye,as well as improved SIt and FL scores after treatment,with a more pronounced improvement in the observation group.Although no marked differences in adverse reactions were observed between the two groups,treatment satisfaction was higher in the observation group.CONCLUSION rhEGF+SH eye drops rendered clinical benefits to patients by effectively ameliorating dry eye and visual impairment with favorable efficacy,fewer adverse reactions,and high safety levels.Thus,this treatment should be promoted in clinical practice.展开更多
Developing a novel drop counter by introducing the Internet of Things concept has been vigorously conducted in recent years. Understanding the newly introduced drop counter’s flow rate control accuracy and flow rate ...Developing a novel drop counter by introducing the Internet of Things concept has been vigorously conducted in recent years. Understanding the newly introduced drop counter’s flow rate control accuracy and flow rate count feature is essential for improving safety in infusion management. This study aimed to verify if the new drop counters could secure accurate flow rate and drip count by conducting actual flow rate measurements using gravimetry and functional evaluation. A drop counter was attached to each drip chamber of the infusion set, and an IV drip was conducted at the 100 ml/h flow rate. The weight of discharged physiological saline was measured to plot trumpet curves. Next, three different types of drop counters were evaluated to determine if they maintained drip count accuracy according to the changes in their position angles. The flow rate errors in all conditions indicated trumpet-like curves, exhibiting an overall error range within ±10% in all observation windows. Although every drop counter successfully detected and measured dripping, it was challenging in some counters to detect dripping when the drip chamber was tilted. In comparing adult and pediatric IV sets, the adult IV set was found to be less likely to detect dripping in the angled position. No significant differences in results were confirmed between high and low flow rates, suggesting that the drop count function would not be affected by the flow rate in the ranges of typical infusion practices. Doppler sensors have a wide range of measurements and high sensitivity;the dripping was detected successfully even when the drip chamber was tilted, probably due to the advantages of these sensors. In contrast, miscounts occurred in those equipped with infrared sensors, which could not detect light intensity changes in tilted positions. Understanding the tendencies in flow rate errors in infusion can be valuable information for infusion management.展开更多
Background: Dry eye and glaucoma are two common pathologies in the elderly, and are very often associated. This association suggests a link between them and between their treatments. Our purpose for this study is to d...Background: Dry eye and glaucoma are two common pathologies in the elderly, and are very often associated. This association suggests a link between them and between their treatments. Our purpose for this study is to determine the prevalence of dry eye in our glaucoma patients treated with eye drops and deduce the factors associated with it. Patients and Methods: We conducted a cross-sectional, analytical study from October 2022 to September 2023 in the ophthalmology department of Garoua Regional Hospital in glaucoma patients aged over 15 years able to answer the Ocular Surface Disease Index (OSDI) questionnaires and treated with antiglaucoma eye drops for more than 3 months. These patients underwent a complete ophthalmological examination and a tear film break-up time test. Results: A total of 73 patients (146 eyes) were examined. The average age of the patients was 47.2 ± 16.5 years, with a male predominance of 54.8%. The prevalence of dry eye syndrome in our patients according to the OSDI score was 56.2% (95% CI) (44.8;67.6). The prevalence of dry eye syndrome on clinical examination of the BUT in the right eye was 83.7% (95% CI) (75.1;92.1) and 79.4% (70.2;88.7) in the left eye. The duration of antiglaucoma treatment was the factor associated with dry eye syndrome (p < 0.05) in glaucoma patients in our setting. Conclusion: Dry Eye Syndrome is common in glaucoma patients on drops in our setting. Treatment duration of more than 1 year seems to be associated with dry eyes.展开更多
Objective: To investigate the therapeutic effect of Ginkgo biloba extract dropping pills combined with butylphthalide capsules on cognitive dysfunction in patients after acute ischemic stroke (AIS) and its impact on s...Objective: To investigate the therapeutic effect of Ginkgo biloba extract dropping pills combined with butylphthalide capsules on cognitive dysfunction in patients after acute ischemic stroke (AIS) and its impact on serum cytokines CRP, IL-6, and Hcy. Methods: This study selected 76 patients with cognitive dysfunction after ischemic stroke who were hospitalized at Zhuji People’s Hospital from January 2023 to January 2024. The patients were divided into two groups. The control group was treated with butylphthalide capsules, while the combination group received Ginkgo biloba extract dropping pills in addition to the treatment given to the control group. The neurological function, cognitive function, activities of daily living, and levels of serum cytokines CRP, IL-6, and Hcy were compared between the two groups after 1 month and 3 months of treatment. Results: The NIHSS scores, MMSE scores, ADL scores, and levels of CRP, IL-6, and Hcy in both groups showed statistically significant differences compared to before treatment (P Conclusion: The combination of Ginkgo biloba extract dropping pills and butylphthalide capsules has a better therapeutic effect on cognitive dysfunction in patients after ischemic stroke. It can improve the neurological function and cognitive function of patients, enhance their ability to perform daily activities, and reduce inflammatory responses.展开更多
The temperature drop of molten metal flowing in open channels is numerically determined. Rectangular, trapezoidal and triangular geometries are considered. The overall heat transfer coefficients for the bottom, side w...The temperature drop of molten metal flowing in open channels is numerically determined. Rectangular, trapezoidal and triangular geometries are considered. The overall heat transfer coefficients for the bottom, side walls and free surface of the channel have been taken from the literature. For each geometry, the volumetric flow rate, mean residence time and temperature drop as a function of the channel inclination angle were determined. The rectangular and trapezoidal geometries present the smallest temperature drops, while the triangular geometry presents the greatest temperature drop. The factors that most affect this drop are the value of the free surface area of the channel, and the average residence time of the molten metal in the channel.展开更多
Based on the temperature situation during the rolling process of 4200 mm/3500 mm medium and thick plates at Baosteel,this article analyzes the influencing factors of temperature changes during the rolling process from...Based on the temperature situation during the rolling process of 4200 mm/3500 mm medium and thick plates at Baosteel,this article analyzes the influencing factors of temperature changes during the rolling process from the perspective of heat transfer theory and the temperature change law during the rolling process.The temperature loss during the four rolling processes is tracked on site,and the temperature drop model parameters during the rolling process of 4200mm/3500mm medium and thick plates at Baosteel are quantitatively provided.It is applied to actual rolling production and has achieved good results.展开更多
Objective:To evaluate the therapeutic effect of recombinant bovine basic fibroblast growth factor(rbFGF)eye gel combined with tobramycin-dexamethasone(TOB-Dex)eye drops on dry eye syndrome(DES)after cataract surgery.M...Objective:To evaluate the therapeutic effect of recombinant bovine basic fibroblast growth factor(rbFGF)eye gel combined with tobramycin-dexamethasone(TOB-Dex)eye drops on dry eye syndrome(DES)after cataract surgery.Methods:86 patients with DES after cataract surgery,admitted from November 2021 to November 2023,were randomly divided into groups.The observation group included 43 patients treated with rbFGF eye gel combined with TOB-Dex eye drops.The reference group included 43 patients treated with TOB-Dex eye drops alone.Multiple indicators,including total effective rate and clinical symptom scores,were compared between the two groups.Results:The total effective rate in the observation group was higher than in the reference group(P<0.05).Before treatment,there were no differences in clinical symptom scores,serum factors,or disease severity scores between the two groups(P>0.05).Three weeks after treatment,the observation group had lower clinical symptom scores,serum factors,and disease severity scores compared to the reference group(P<0.05).The adverse reaction rate in the observation group was lower than in the reference group(P<0.05).Conclusion:rbFGF eye gel combined with TOB-Dex eye drops can improve the clinical efficacy for patients with DES after cataract surgery,alleviate disease symptoms,reduce inflammatory responses,and have fewer adverse reactions.展开更多
With the development of deep learning, many motor imagerybrain-computer interfaces based on convolutional neural networks(CNNs) show outstanding performances. However, the trial number ofEEG in the training set is usu...With the development of deep learning, many motor imagerybrain-computer interfaces based on convolutional neural networks(CNNs) show outstanding performances. However, the trial number ofEEG in the training set is usually limited, and redundancy extensivelyexists in multiple channel EEG. Thus, overfitting often appears in CNNbased motor imagery recognition model and greatly affects the performancesof model. In this paper, channel drop out is proposed to addressthis problem by data augmentation and ensemble learning. Specifically,one of all EEG channels will be dropped and replaced by the mean signalof all EEG channels. In this way, the trial number in the training setwas enlarged by channel drop out. And at the testing stage, all the EEGtrials processed by channel drop out were fed to the CNN model and theaverage output probabilities of them were applied to determine the prediction.The experiments were conducted on two popular CNN modelsapplied in motor imagery BCI and BCI Competition IV datasets 2a toverify the performances of the proposed channel drop out approach. Theresults show that average improvements provided by channel drop outin two-category or four-category motor imagery classification are 2.83%and 2.65% compared with the original CNN model. So the channel dropout approach significantly improves the performances of motor imagerybased BCI.展开更多
AIM:To combine pressure and flow parameter, pressure drop coefficient(CDP) will result in better clinical outcomes in comparison to the fractional flow reserve(FFR) group. METHODS:To test this hypothesis, a comparison...AIM:To combine pressure and flow parameter, pressure drop coefficient(CDP) will result in better clinical outcomes in comparison to the fractional flow reserve(FFR) group. METHODS:To test this hypothesis, a comparison was made between the FFR < 0.75 and CDP > 27.9 groups in this study, for the major adverse cardiac events [major adverse cardiac events(MACE): Primary outcome] and patients’ quality of life(secondary outcome). Further, a comparison was also made between the survival curves for the FFR < 0.75 and CDP > 27.9 groups. Two-tailed χ~2 test proportions were performed for the comparison of primary and secondary outcomes. Kaplan-Meier survival analysis was performed to compare the survival curves of FFR < 0.75 and CDP > 27.9 groups(MedcalcV10.2, Mariakerke, Belgium). Results were considered statistically significant for P < 0.05. RESULTS: The primary outcomes(%MACE) in the FFR < 0.75 group(20%, 4 out of 20) was not statistically different(P = 0.24) from the %MACE occurring in CDP > 27.9 group(8.57%, 2 out of 35). Noteworthy is the reduction in the %MACE in the CDP > 27.9 group, in comparison to the FFR < 0.75 group. Further, the secondary outcomes were not statistically significant between the FFR < 0.75 and CDP > 27.9 groups. Survival analysis results suggest that the survival time for the CDP > 27.9 group(n = 35) is significantly higher(P = 0.048) in comparison to the survival time for the FFR < 0.75 group(n = 20). The results remained similar for a FFR = 0.80 cut-off. CONCLUSION: Based on the above, CDP could prove to be a better diagnostic end-point for clinical revascularization decision-making in the cardiac catheterization laboratories.展开更多
AIM To investigate the patient-outcomes of newly developed pressure drop coefficient(CDP) in diagnosing epicardial stenosis(ES) in the presence of concomitant microvascular disease(MVD).METHODS Patients from our clini...AIM To investigate the patient-outcomes of newly developed pressure drop coefficient(CDP) in diagnosing epicardial stenosis(ES) in the presence of concomitant microvascular disease(MVD).METHODS Patients from our clinical trial were divided into two subgroups with:(1) cut-off of coronary flow reserve(CFR) < 2.0;and(2) diabetes.First,correlations were performed for both subgroups between CDP and hyperemic microvascular resistance(HMR),a diagnostic parameter for assessing the severity of MVD.Linear regression analysis was used for these correlations.Further,in each of the subgroups,comparisons were made between fractional flow reserve(FFR) < 0.75 and CDP > 27.9 groups for assessing major adverse cardiac events(MACE:Primary outcome).Comparisons were also made between the survival curves for FFR < 0.75 and CDP > 27.9 groups.Two tailed chi-squared and Fischer's exact tests were performed for comparison of the primary outcomes,and the log-rank test was used to compare the Kaplan-Meier survival curves.P < 0.05 for all tests was considered statistically significant.RESULTS Significant linear correlations were observed between CDP and HMR for both CFR < 2.0(r = 0.58,P < 0.001) and diabetic(r = 0.61,P < 0.001) patients.In the CFR < 2.0 subgroup,the %MACE(primary outcomes) for CDP > 27.9 group(7.7%,2/26) was lower than FFR < 0.75 group(3/14,21.4%);P = 0.21.Similarly,in the diabetic subgroup,the %MACE for CDP > 27.9 group(12.5%,2/16) was lower than FFR < 0.75 group(18.2%,2/11);P = 0.69.Survival analysis for CFR < 2.0 subgroup indicated better event-free survival for CDP > 27.9 group(n = 26) when compared with FFR < 0.75 group(n = 14);P = 0.10.Similarly,for the diabetic subgroup,CDP > 27.9 group(n = 16) showed higher survival times compared to FFR group(n = 11);P = 0.58.CONCLUSION CDP correlated significantly with HMR and resulted in better %MACE as well as survival rates in comparison to FFR.These positive trends demonstrate that CDP could be a potential diagnostic endpoint for delineating MVD with or without ES.展开更多
Energy-absorbing rockbolts have been widely adopted in burst-prone excavation support, and their serviceability is closely related to the frequency and magnitude of seismic events. In this research, the splittube drop...Energy-absorbing rockbolts have been widely adopted in burst-prone excavation support, and their serviceability is closely related to the frequency and magnitude of seismic events. In this research, the splittube drop test with varying impact energy was conducted to reproduce the dynamic performance of MP1rockbolts under a wide range of seismic event magnitudes. The test results showed that the impact process could be subdivided into four distinct stages, i.e. mobilization, strain hardening, plastic flow(ductile), and rebound stage, of which strain hardening and plastic flow are the primary energy absorbing stages. As the impact energy per drop increases from 8.1 to 46.7 k J, the strain rate of the shank varies between 1.20 and 2.70 s^(-1), and the average impact load is between 240 and 270kN, which may be considered as constant. The MP1 rockbolt has a cumulative maximum energy absorption(CMEA) of 31.9–40.0 k J/m, with an average of 35.0 k J/m, and the elongation rate is 11.4%–14.7%, with an average of 12.7%, both of which are negatively correlated with the impact energy per drop. Regression analysis shows that energy absorption and shank elongation, as well as momentum input and impact duration,conform to the linear relationship. The complete dynamic capacity envelope of MP1 rockbolts is proposed, which reflects the dynamic bearing capacity, elongation, and distinct stages. This study is helpful to better understand the dynamic characteristics of energy-absorbing rockbolts and assist design engineers in robust reinforcement systems design to mitigate rockburst damage in seismically active underground excavations.展开更多
AIM:To evaluate effects of endogenous dopamine induced by low concentration atropine eye drops on choroidal neovascularization(CNV)in high myopia mice.METHODS:The C57BL/6J mice were deprived of the right eye for 4wk,a...AIM:To evaluate effects of endogenous dopamine induced by low concentration atropine eye drops on choroidal neovascularization(CNV)in high myopia mice.METHODS:The C57BL/6J mice were deprived of the right eye for 4wk,and the high myopia was diagnosed by optometry,the diopter was less than-6.00 D,and CNV was induced by 532 nm laser.The changes of dopamine D1 receptor(DRD1),dopamine D2 receptor(DRD2),and vascular endothelial growth factor A(VEGFA)were detected by Western blot technology at 0.5,1,2h,and 7d after 0.01%,0.05%,and 0.1%atropine eye drops,respectively,the area of CNV was measured.RESULTS:Significant increases were observed on the expression of DRD2 in mouse high myopia model at 0.5,1,2h,7d with 0.05%and 0.1%atropine eye drops(P<0.05).Significant decreases were observed on the expression of DRD1 and VEGFA in mouse high myopia model at 0.5,1,2h,7d with 0.05%and 0.1%atropine eye drops(P<0.05).The area of CNV induced by laser in the drug-treated group was significantly smaller than that in the control group,and the higher the concentration,the more significant the inhibitory effect(P<0.05).CONCLUSION:The 0.01%,0.05%,0.1%atropine eye drops can decrease the level of VEGFA and inhibit high myopia CNV indirectly by up-regulating the level of DRD2 and down-regulating the level of DRD1,and the effect of 0.05%and 0.1%atropine eye drops is more significant.展开更多
文摘The aim of this paper is to highlight the fact that students enter their higher education careers underprepared and fail their engineering studies due to the lack of various life skills. The South African Government is attempting to redress the social inequalities which prevailed in the education sector during the apartheid era. However, many students attempting their higher education studies are in many respects still under-prepared. This is mainly due to insufficient life skills, communication skills, numeric skills, and literacy skills. In the current study it was established, by means of a self-administered questionnaire, that students' lacking time of management skills, and study skills, are conditioned by their schooling not to value or use prescribed text books. These results re-emphasise the fact that students drop out of the programme for reasons other than academic performance and underline the need for effective measures toward student support and effective student learning.
文摘BACKGROUND Foot drop causes considerable disability.The ankle-dorsiflexion is either weak or lost completely.Additionally,the ankle eversion and toe extensions are also impaired.This results in a high steppage gait while walking.Overall,the gait is awkward;there is greater energy consumption;increased proneness to sustain injury of the forefoot;and more frequent falling during walking.AIM To document the clinical and epidemiological profile of foot drop patients in our population and evaluate the outcome of tibialis posterior(TP)tendon transfer for restoring the lost dorsiflexion in foot drop.METHODS The study was carried out at the National Institute of Rehabilitation Medicine in Islamabad over a period of 7 years.It included patients of all sexes and ages who presented with foot drop and had no contraindications for the procedure of TP tendon transfer.Exclusion criteria were patients who had contraindications for the operation.For instance,paralyzed posterior leg compartment muscles,Achilles tendon contracture,stiff ankle or toes,unstable ankle joint,weak gastrocnemius and scarred skin spanning over the route of planned tendon transfer.Also,patients who had the foot drop as a result of disc prolapses or brain diseases were excluded.Convenience sampling technique was used.The circum-tibial route of TP tendon transfer was employed.RESULTS Out of 37 patients,26(70.27%)were males whereas 11(29.72%)were females.The mean age was 22.59±8.19 years.Among the underlying causes of foot drop,road traffic accidents constituted the most common cause,found among 20(54.05%)patients.The share of complications included wound infections in 3(8.10%)patients and hypertrophic scars in 2(5.40%)patients.At 1-year postoperative follow-up visits,the outcome was excellent in 8(21.62%),good in 20(54.05%)and moderate in 9(24.31%).CONCLUSION The majority of cases of foot drop resulted from road traffic accidents that directly involved the common peroneal nerve.TP tendon transfer through the circumtibial route was found to be an easily executed effective operation which restored good dorsiflexion of the ankle among the majority of patients.
基金the support of the National Natural Science Foundation of China(22278234,21776151)。
文摘An artificial neural network(ANN)method is introduced to predict drop size in two kinds of pulsed columns with small-scale data sets.After training,the deviation between calculate and experimental results are 3.8%and 9.3%,respectively.Through ANN model,the influence of interfacial tension and pulsation intensity on the droplet diameter has been developed.Droplet size gradually increases with the increase of interfacial tension,and decreases with the increase of pulse intensity.It can be seen that the accuracy of ANN model in predicting droplet size outside the training set range is reach the same level as the accuracy of correlation obtained based on experiments within this range.For two kinds of columns,the drop size prediction deviations of ANN model are 9.6%and 18.5%and the deviations in correlations are 11%and 15%.
文摘Background: Cataract surgery is the most frequently performed surgery worldwide. Posterior capsule rupture (PCR) remains one of the most common complications of cataract surgery and a major risk factor for poor visual outcomes. Cataract surgeries complicated by PCR and vitreous loss are managed with anterior vitrectomy at the time of surgery. However, the situation can be further complicated by dropping lens particles into the vitreous cavity necessitating a secondary pars plana vitrectomy (PPV). Purpose: To compare the visual outcomes and risk of rhegmatogenous retinal detachment (RRD) between eyes that required anterior vitrectomy (AV) alone for the management of vitreous loss and eyes that required AV and subsequent PPV for the management of dropped nuclear lens fragments (DNLF) following cataract surgery complicated by PCR in a tertiary care teaching hospital in Saudi Arabia. Methods: Medical records of patients in whom PCR occurred during phacoemulsification cataract surgery requiring AV or subsequent PPV for DNLF were retrospectively reviewed over a 6-year period from January 2016 to December 2021. Results: PCR occurred in 183 (2.3%) of 7757 consecutive eyes that underwent phacoemulsification cataract surgery during the study period. Seven eyes were excluded from analysis for missing data or short follow-up. Of the 176 eyes, 147 eyes (83.5%) were managed with AV alone, and the remaining 29 eyes (16.5%) underwent a secondary PPV for DNLF. After excluding eyes with pre-existing ocular pathology, final best-corrected visual acuity (BCVA) was similar in both groups with a mean of 0.32 logMAR (P = 0.99). Two of 147 eyes (1.4%) in the AV group developed RRD with poor final BCVA whereas none of the eyes in DNLF group developed RRD. Conclusion: The risk of RRD is lower in eyes that required PPV for DNLF than in eyes that were managed with AV alone following PCR during cataract surgery. The poor visual outcomes in eyes that suffered RRD underscore the importance of postoperative retinal examination and early detection of retinal breaks.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.52071160 and 52071203)the 333-Key-Industry Talent Project of Jiangsu Scientific Committee(Grant No.JTO 2022-21).
文摘The water-drop-shaped pressure hull has a good streamline,which has good application prospect in the underwater observatory.Therefore,this study conducted analytical,experimental and numerical investigation of the buckling properties of water-drop-shaped pressure hulls under hydrostatic pressure.A water-drop experiment was conducted to design water-drop-shaped pressure hulls with various shape indices.The critical loads for the water-drop-shaped pressure hulls were resolved by using Mushtari’s formula.Several numerical simulations including linear buckling analysis and nonlinear buckling analysis including eigenmode imperfections were performed.The results indicated that the critical loads resolved by Mushtari's formula were in good agreement with the linear buckling loads from the numerical simulations.This formula can be extended to estimate the buckling capacity of water-drop-shaped pressure hulls.In addition,three groups of pressure hulls were fabricated by using stereolithography,a rapid prototyping technique.Subsequently,three groups of the pressure hulls were subjected to ultrasonic measurements,optical scanning,hydrostatic testing and numerical analysis.The experimental results were consistent with the numerical results.The results indicate that the sharp end of the water-drop-shaped pressure hulls exhibited instability compared with the blunt end.This paper provides a new solution to the limitations of experimental studies on the water-drop-shaped pressure hulls as well as a new configuration and evaluation method for underwater observatories.
基金the support of the Opening Fund of State Key Laboratory of Multiphase Flow in Power Engineering(SKLMF-KF-2102)。
文摘Accurate prediction of the frictional pressure drop is important for the design and operation of subsea oil and gas transporting system considering the length of the pipeline. The applicability of the correlations to pipeline-riser flow needs evaluation since the flow condition in pipeline-riser is quite different from the original data where they were derived from. In the present study, a comprehensive evaluation of 24prevailing correlation in predicting frictional pressure drop is carried out based on experimentally measured data of air-water and air-oil two-phase flows in pipeline-riser. Experiments are performed in a system having different configuration of pipeline-riser with the inclination of the downcomer varied from-2°to-5°to investigated the effect of the elbow on the frictional pressure drop in the riser. The inlet gas velocity ranges from 0.03 to 6.2 m/s, and liquid velocity varies from 0.02 to 1.3 m/s. A total of885 experimental data points including 782 on air-water flows and 103 on air-oil flows are obtained and used to access the prediction ability of the correlations. Comparison of the predicted results with the measured data indicate that a majority of the investigated correlations under-predict the pressure drop on severe slugging. The result of this study highlights the requirement of new method considering the effect of pipe layout on the frictional pressure drop.
基金the China Scholarship Council for the award of fellowship and funding No.201908510177 and No.202106050030funded by dtec.bw-Digitalization and Technology Research Center of the Bundeswehr which project DMF+1 种基金The AMABML project founded by the Zentrum für Hochleistungsmaterialien(ZHM)DEZAIN project for financial support via grant from GIF,the German-Israeli Foundation for Scientific Research and Development。
文摘The voltage drop appearing at Mg anode-electrolyte interface is a critical issue for the battery power and energy density of aqueous primary Mg-air batteries.The respective voltage loss is typically assigned to the deposits layer forming on the anode surface during discharge.In this work,we experimentally and computationally investigate the critical factors affecting the voltage drop at Mg anode towards a deeper understanding of the contribution of deposit and its growth.A two-dimensional(2D)mathematical model is proposed to compute the voltage drop of Mg-0.15Ca wt.%alloy(Mg-0.15Ca)by means of a semi-empirical formulas and experiments-based modification model,considering the effect of discharge current density,the negative difference effect(NDE)and surface deposits layer itself.This model is utilized to simulate the discharge potential of the anode at predefined experimental current densities.The computed voltage drop(half-cell voltage)is in good agreement with the experimental value.The applicability of the mathematical model is successfully validated on the second material(namely high-purity Mg).
基金supported by a grant from the fund:State Grid Inner Mongolia East Power Co.,Ltd.Science and Technology Project(SGMDTL00YWJS2200994).
文摘Currently,both regulated and deregulated power trading exist in China’s power system,which has caused imbalanced funds in the electricity market.In this paper,a simulation analysis of the electricity market with wind energy resources is conducted,and the calculation methods of unbalanced funds are investigated systematically.In detail,the calculation formulas of unbalanced funds are illustrated based on their definition,and a two-track electricity market clearing model is established.Firstly,the concept of the dual-track system is explained,and the specific calculation formulas of various types of unbalanced funds are provided.Next,considering the renewable energy consumption,the market clearing model based on DC power flow is constructed and solved;by combining fitting methods of mid-and long-term curves,the unbalanced funds are calculated based on clearing results and formulas.
基金Supported by Tianjin Health Research Project,No.TJWJ2023MS062。
文摘BACKGROUND Dry eye syndrome(DES)after diabetic cataract surgery can seriously affect the patient’s quality of life.Therefore,effective alleviation of symptoms in patients with this disease has important clinical significance.AIM To explore the clinical effect of recombinant human epidermal growth factor(rhEGF)plus sodium hyaluronate(SH)eye drops on DES after cataract surgery in patients with diabetes.METHODS We retrospectively evaluated 82 patients with diabetes who experienced DES after cataract surgery at Tianjin Beichen Hospital,Affiliated Hospital of Nankai University between April 2021 and April 2023.They were classified into an observation group(42 cases,rhEGF+SH eye drops)and a control group(40 cases,SH eye drops alone),depending on the different treatment schemes.The therapeutic efficacy,dry eye symptom score,tear film breakup time(TFBUT),basic tear secretion score[assessed using Schirmer I test(SIt)],corneal fluorescein staining(FL)score,tear inflammatory markers,adverse reactions during treat-ment,and treatment satisfaction were compared between the two groups.RESULTS Therapeutic efficacy was higher in the observation group compared with the control group.Both groups showed improved TFBUT and dry eye,as well as improved SIt and FL scores after treatment,with a more pronounced improvement in the observation group.Although no marked differences in adverse reactions were observed between the two groups,treatment satisfaction was higher in the observation group.CONCLUSION rhEGF+SH eye drops rendered clinical benefits to patients by effectively ameliorating dry eye and visual impairment with favorable efficacy,fewer adverse reactions,and high safety levels.Thus,this treatment should be promoted in clinical practice.
文摘Developing a novel drop counter by introducing the Internet of Things concept has been vigorously conducted in recent years. Understanding the newly introduced drop counter’s flow rate control accuracy and flow rate count feature is essential for improving safety in infusion management. This study aimed to verify if the new drop counters could secure accurate flow rate and drip count by conducting actual flow rate measurements using gravimetry and functional evaluation. A drop counter was attached to each drip chamber of the infusion set, and an IV drip was conducted at the 100 ml/h flow rate. The weight of discharged physiological saline was measured to plot trumpet curves. Next, three different types of drop counters were evaluated to determine if they maintained drip count accuracy according to the changes in their position angles. The flow rate errors in all conditions indicated trumpet-like curves, exhibiting an overall error range within ±10% in all observation windows. Although every drop counter successfully detected and measured dripping, it was challenging in some counters to detect dripping when the drip chamber was tilted. In comparing adult and pediatric IV sets, the adult IV set was found to be less likely to detect dripping in the angled position. No significant differences in results were confirmed between high and low flow rates, suggesting that the drop count function would not be affected by the flow rate in the ranges of typical infusion practices. Doppler sensors have a wide range of measurements and high sensitivity;the dripping was detected successfully even when the drip chamber was tilted, probably due to the advantages of these sensors. In contrast, miscounts occurred in those equipped with infrared sensors, which could not detect light intensity changes in tilted positions. Understanding the tendencies in flow rate errors in infusion can be valuable information for infusion management.
文摘Background: Dry eye and glaucoma are two common pathologies in the elderly, and are very often associated. This association suggests a link between them and between their treatments. Our purpose for this study is to determine the prevalence of dry eye in our glaucoma patients treated with eye drops and deduce the factors associated with it. Patients and Methods: We conducted a cross-sectional, analytical study from October 2022 to September 2023 in the ophthalmology department of Garoua Regional Hospital in glaucoma patients aged over 15 years able to answer the Ocular Surface Disease Index (OSDI) questionnaires and treated with antiglaucoma eye drops for more than 3 months. These patients underwent a complete ophthalmological examination and a tear film break-up time test. Results: A total of 73 patients (146 eyes) were examined. The average age of the patients was 47.2 ± 16.5 years, with a male predominance of 54.8%. The prevalence of dry eye syndrome in our patients according to the OSDI score was 56.2% (95% CI) (44.8;67.6). The prevalence of dry eye syndrome on clinical examination of the BUT in the right eye was 83.7% (95% CI) (75.1;92.1) and 79.4% (70.2;88.7) in the left eye. The duration of antiglaucoma treatment was the factor associated with dry eye syndrome (p < 0.05) in glaucoma patients in our setting. Conclusion: Dry Eye Syndrome is common in glaucoma patients on drops in our setting. Treatment duration of more than 1 year seems to be associated with dry eyes.
文摘Objective: To investigate the therapeutic effect of Ginkgo biloba extract dropping pills combined with butylphthalide capsules on cognitive dysfunction in patients after acute ischemic stroke (AIS) and its impact on serum cytokines CRP, IL-6, and Hcy. Methods: This study selected 76 patients with cognitive dysfunction after ischemic stroke who were hospitalized at Zhuji People’s Hospital from January 2023 to January 2024. The patients were divided into two groups. The control group was treated with butylphthalide capsules, while the combination group received Ginkgo biloba extract dropping pills in addition to the treatment given to the control group. The neurological function, cognitive function, activities of daily living, and levels of serum cytokines CRP, IL-6, and Hcy were compared between the two groups after 1 month and 3 months of treatment. Results: The NIHSS scores, MMSE scores, ADL scores, and levels of CRP, IL-6, and Hcy in both groups showed statistically significant differences compared to before treatment (P Conclusion: The combination of Ginkgo biloba extract dropping pills and butylphthalide capsules has a better therapeutic effect on cognitive dysfunction in patients after ischemic stroke. It can improve the neurological function and cognitive function of patients, enhance their ability to perform daily activities, and reduce inflammatory responses.
文摘The temperature drop of molten metal flowing in open channels is numerically determined. Rectangular, trapezoidal and triangular geometries are considered. The overall heat transfer coefficients for the bottom, side walls and free surface of the channel have been taken from the literature. For each geometry, the volumetric flow rate, mean residence time and temperature drop as a function of the channel inclination angle were determined. The rectangular and trapezoidal geometries present the smallest temperature drops, while the triangular geometry presents the greatest temperature drop. The factors that most affect this drop are the value of the free surface area of the channel, and the average residence time of the molten metal in the channel.
文摘Based on the temperature situation during the rolling process of 4200 mm/3500 mm medium and thick plates at Baosteel,this article analyzes the influencing factors of temperature changes during the rolling process from the perspective of heat transfer theory and the temperature change law during the rolling process.The temperature loss during the four rolling processes is tracked on site,and the temperature drop model parameters during the rolling process of 4200mm/3500mm medium and thick plates at Baosteel are quantitatively provided.It is applied to actual rolling production and has achieved good results.
文摘Objective:To evaluate the therapeutic effect of recombinant bovine basic fibroblast growth factor(rbFGF)eye gel combined with tobramycin-dexamethasone(TOB-Dex)eye drops on dry eye syndrome(DES)after cataract surgery.Methods:86 patients with DES after cataract surgery,admitted from November 2021 to November 2023,were randomly divided into groups.The observation group included 43 patients treated with rbFGF eye gel combined with TOB-Dex eye drops.The reference group included 43 patients treated with TOB-Dex eye drops alone.Multiple indicators,including total effective rate and clinical symptom scores,were compared between the two groups.Results:The total effective rate in the observation group was higher than in the reference group(P<0.05).Before treatment,there were no differences in clinical symptom scores,serum factors,or disease severity scores between the two groups(P>0.05).Three weeks after treatment,the observation group had lower clinical symptom scores,serum factors,and disease severity scores compared to the reference group(P<0.05).The adverse reaction rate in the observation group was lower than in the reference group(P<0.05).Conclusion:rbFGF eye gel combined with TOB-Dex eye drops can improve the clinical efficacy for patients with DES after cataract surgery,alleviate disease symptoms,reduce inflammatory responses,and have fewer adverse reactions.
基金Supported by the National Natural Science Foundation of China,grants 61906152 and 61976177Key Research and Development Program of Shaanxi(Program No.2021GY-080).
文摘With the development of deep learning, many motor imagerybrain-computer interfaces based on convolutional neural networks(CNNs) show outstanding performances. However, the trial number ofEEG in the training set is usually limited, and redundancy extensivelyexists in multiple channel EEG. Thus, overfitting often appears in CNNbased motor imagery recognition model and greatly affects the performancesof model. In this paper, channel drop out is proposed to addressthis problem by data augmentation and ensemble learning. Specifically,one of all EEG channels will be dropped and replaced by the mean signalof all EEG channels. In this way, the trial number in the training setwas enlarged by channel drop out. And at the testing stage, all the EEGtrials processed by channel drop out were fed to the CNN model and theaverage output probabilities of them were applied to determine the prediction.The experiments were conducted on two popular CNN modelsapplied in motor imagery BCI and BCI Competition IV datasets 2a toverify the performances of the proposed channel drop out approach. Theresults show that average improvements provided by channel drop outin two-category or four-category motor imagery classification are 2.83%and 2.65% compared with the original CNN model. So the channel dropout approach significantly improves the performances of motor imagerybased BCI.
基金Supported by VA Merit Review Grant(I01CX000342-01),Department of Veteran Affairs
文摘AIM:To combine pressure and flow parameter, pressure drop coefficient(CDP) will result in better clinical outcomes in comparison to the fractional flow reserve(FFR) group. METHODS:To test this hypothesis, a comparison was made between the FFR < 0.75 and CDP > 27.9 groups in this study, for the major adverse cardiac events [major adverse cardiac events(MACE): Primary outcome] and patients’ quality of life(secondary outcome). Further, a comparison was also made between the survival curves for the FFR < 0.75 and CDP > 27.9 groups. Two-tailed χ~2 test proportions were performed for the comparison of primary and secondary outcomes. Kaplan-Meier survival analysis was performed to compare the survival curves of FFR < 0.75 and CDP > 27.9 groups(MedcalcV10.2, Mariakerke, Belgium). Results were considered statistically significant for P < 0.05. RESULTS: The primary outcomes(%MACE) in the FFR < 0.75 group(20%, 4 out of 20) was not statistically different(P = 0.24) from the %MACE occurring in CDP > 27.9 group(8.57%, 2 out of 35). Noteworthy is the reduction in the %MACE in the CDP > 27.9 group, in comparison to the FFR < 0.75 group. Further, the secondary outcomes were not statistically significant between the FFR < 0.75 and CDP > 27.9 groups. Survival analysis results suggest that the survival time for the CDP > 27.9 group(n = 35) is significantly higher(P = 0.048) in comparison to the survival time for the FFR < 0.75 group(n = 20). The results remained similar for a FFR = 0.80 cut-off. CONCLUSION: Based on the above, CDP could prove to be a better diagnostic end-point for clinical revascularization decision-making in the cardiac catheterization laboratories.
基金Supported by VA Merit Review Grant,Department of Veteran Affairs(PI:Dr.Rupak K Banerjee)No.I01CX000342-01
文摘AIM To investigate the patient-outcomes of newly developed pressure drop coefficient(CDP) in diagnosing epicardial stenosis(ES) in the presence of concomitant microvascular disease(MVD).METHODS Patients from our clinical trial were divided into two subgroups with:(1) cut-off of coronary flow reserve(CFR) < 2.0;and(2) diabetes.First,correlations were performed for both subgroups between CDP and hyperemic microvascular resistance(HMR),a diagnostic parameter for assessing the severity of MVD.Linear regression analysis was used for these correlations.Further,in each of the subgroups,comparisons were made between fractional flow reserve(FFR) < 0.75 and CDP > 27.9 groups for assessing major adverse cardiac events(MACE:Primary outcome).Comparisons were also made between the survival curves for FFR < 0.75 and CDP > 27.9 groups.Two tailed chi-squared and Fischer's exact tests were performed for comparison of the primary outcomes,and the log-rank test was used to compare the Kaplan-Meier survival curves.P < 0.05 for all tests was considered statistically significant.RESULTS Significant linear correlations were observed between CDP and HMR for both CFR < 2.0(r = 0.58,P < 0.001) and diabetic(r = 0.61,P < 0.001) patients.In the CFR < 2.0 subgroup,the %MACE(primary outcomes) for CDP > 27.9 group(7.7%,2/26) was lower than FFR < 0.75 group(3/14,21.4%);P = 0.21.Similarly,in the diabetic subgroup,the %MACE for CDP > 27.9 group(12.5%,2/16) was lower than FFR < 0.75 group(18.2%,2/11);P = 0.69.Survival analysis for CFR < 2.0 subgroup indicated better event-free survival for CDP > 27.9 group(n = 26) when compared with FFR < 0.75 group(n = 14);P = 0.10.Similarly,for the diabetic subgroup,CDP > 27.9 group(n = 16) showed higher survival times compared to FFR group(n = 11);P = 0.58.CONCLUSION CDP correlated significantly with HMR and resulted in better %MACE as well as survival rates in comparison to FFR.These positive trends demonstrate that CDP could be a potential diagnostic endpoint for delineating MVD with or without ES.
基金CCTEG Coal Mining Research Institute(No.TDKC-2022-MS-01)the National Natural Science Foundation of China(No.52274123)the Mining Education Australia(MEA),Collaborative Research Grant Scheme(No.RS-59041).
文摘Energy-absorbing rockbolts have been widely adopted in burst-prone excavation support, and their serviceability is closely related to the frequency and magnitude of seismic events. In this research, the splittube drop test with varying impact energy was conducted to reproduce the dynamic performance of MP1rockbolts under a wide range of seismic event magnitudes. The test results showed that the impact process could be subdivided into four distinct stages, i.e. mobilization, strain hardening, plastic flow(ductile), and rebound stage, of which strain hardening and plastic flow are the primary energy absorbing stages. As the impact energy per drop increases from 8.1 to 46.7 k J, the strain rate of the shank varies between 1.20 and 2.70 s^(-1), and the average impact load is between 240 and 270kN, which may be considered as constant. The MP1 rockbolt has a cumulative maximum energy absorption(CMEA) of 31.9–40.0 k J/m, with an average of 35.0 k J/m, and the elongation rate is 11.4%–14.7%, with an average of 12.7%, both of which are negatively correlated with the impact energy per drop. Regression analysis shows that energy absorption and shank elongation, as well as momentum input and impact duration,conform to the linear relationship. The complete dynamic capacity envelope of MP1 rockbolts is proposed, which reflects the dynamic bearing capacity, elongation, and distinct stages. This study is helpful to better understand the dynamic characteristics of energy-absorbing rockbolts and assist design engineers in robust reinforcement systems design to mitigate rockburst damage in seismically active underground excavations.
文摘AIM:To evaluate effects of endogenous dopamine induced by low concentration atropine eye drops on choroidal neovascularization(CNV)in high myopia mice.METHODS:The C57BL/6J mice were deprived of the right eye for 4wk,and the high myopia was diagnosed by optometry,the diopter was less than-6.00 D,and CNV was induced by 532 nm laser.The changes of dopamine D1 receptor(DRD1),dopamine D2 receptor(DRD2),and vascular endothelial growth factor A(VEGFA)were detected by Western blot technology at 0.5,1,2h,and 7d after 0.01%,0.05%,and 0.1%atropine eye drops,respectively,the area of CNV was measured.RESULTS:Significant increases were observed on the expression of DRD2 in mouse high myopia model at 0.5,1,2h,7d with 0.05%and 0.1%atropine eye drops(P<0.05).Significant decreases were observed on the expression of DRD1 and VEGFA in mouse high myopia model at 0.5,1,2h,7d with 0.05%and 0.1%atropine eye drops(P<0.05).The area of CNV induced by laser in the drug-treated group was significantly smaller than that in the control group,and the higher the concentration,the more significant the inhibitory effect(P<0.05).CONCLUSION:The 0.01%,0.05%,0.1%atropine eye drops can decrease the level of VEGFA and inhibit high myopia CNV indirectly by up-regulating the level of DRD2 and down-regulating the level of DRD1,and the effect of 0.05%and 0.1%atropine eye drops is more significant.