An increase in methane,spontaneous fire and bumping hazards in Polish hard coal mines,observed in the last two decades,led to the need to elaborate the tools allowing proper selection of a range of preventive measures...An increase in methane,spontaneous fire and bumping hazards in Polish hard coal mines,observed in the last two decades,led to the need to elaborate the tools allowing proper selection of a range of preventive measures to fight them at the stage of designing coal extraction.Designing the production of a coal seams in the conditions of associated methane and spontaneous fires hazards in Polish hard coal mines requires elaboration of the design standards for coal panels in gassy coal seams.This paper presents the guidelines on how to design production in the conditions of associated methane and spontaneous fire hazards.Presented tools and methodology since the very first research were many times verified by daily mining operations in the conditions of associated methane and spontaneous fire hazards,which confirms their significant contribution to the development of safe and economical mining operations.展开更多
Spontaneous imbibition(SI)is an important mechanism for enhancing oil recovery in low-permeability reservoirs.Due to the strong heterogeneity,and the non-Darcy flow,the construction of SI model for lowpermeability res...Spontaneous imbibition(SI)is an important mechanism for enhancing oil recovery in low-permeability reservoirs.Due to the strong heterogeneity,and the non-Darcy flow,the construction of SI model for lowpermeability reservoirs is extremely challenging.Commonly,traditional SI models based on single or averaged capillary tortuosity ignore the influence of heterogeneity of pore seepage channels and the threshold pressure(TP)on imbibition.Therefore,in this work,based on capillary model and fractal theory,a mathematical model of characterizing SI considering heterogeneity of pore seepage channels is established.On this basis,the threshold pressure was introduced to determine the pore radius at which the wetted phase can displace oil.The proposed new SI model was verified by imbibition experimental data.The study shows that for weakly heterogeneous cores with permeability of 0-1 m D,the traditional SI model can characterize the imbibition process relatively accurately,and the new imbibition model can increase the coefficient of determination by 1.05 times.However,traditional model has serious deviations in predicting the imbibition recovery for cores with permeability of 10-50 m D.The new SI model coupling with heterogeneity of pore seepage channels and threshold pressure effectively solves this problem,and the determination coefficient is increased from 0.344 to 0.922,which is increased by2.68 times.For low-permeability reservoirs,the production of the oil in transitional pores(0.01-0.1μm)and mesopores(0.1-1μm)significantly affects the imbibition recovery,as the research shows that when the heterogeneity of pore seepage channels is ignored,the oil recovery in transitional pores and mesopores decreases by 7.54%and 4.26%,respectively.Sensitivity analysis shows that increasing interfacial tension,decreasing contact angle,oil-water viscosity ratio and threshold pressure will increase imbibition recovery.In addition,there are critical values for the influence of these factors on the imbibition recovery,which provides theoretical support for surfactant optimization.展开更多
A hydrotalcite(layered double hydroxide, LDH) inhibitor which is suitable for the whole process of coal spontaneous combustion and a LDH inhibitor containing rare earth lanthanum elements were prepared. The inhibition...A hydrotalcite(layered double hydroxide, LDH) inhibitor which is suitable for the whole process of coal spontaneous combustion and a LDH inhibitor containing rare earth lanthanum elements were prepared. The inhibition effect and mechanism were analyzed by scanning electron microscopy(SEM),X-ray diffraction(XRD), thermal performance analysis, in-situ diffuse reflectance infrared spectroscopy and temperature-programmed experiment. The results have shown that the inhibitor containing lanthanum can play a good inhibitory role in every stage of coal oxidation. During the slow oxidation of coal samples, the inhibitor containing lanthanum ions can slow down the oxidation process of coal and increase the initial temperature of coal spontaneous combustion. At the same time, because the hydroxyl groups in LDHs are connected with-COO-groups on the coal surface through hydrogen bonds, the stability of coal is improved. With the increase of temperature, LDHs can remove interlayer water molecules and reduce the surface temperature of coal. CO release rate of coal samples decreases significantly after adding inhibitor containing lanthanum element, and the maximum inhibition rate of the inhibitor is 58.1%.展开更多
Slickwater fracturing fluids have gained widespread application in the development of tight oil reservoirs. After the fracturing process, the active components present in slickwater can directly induce spontaneous imb...Slickwater fracturing fluids have gained widespread application in the development of tight oil reservoirs. After the fracturing process, the active components present in slickwater can directly induce spontaneous imbibition within the reservoir. Several variables influence the eventual recovery rate within this procedure, including slickwater composition, formation temperature, degree of reservoir fracture development, and the reservoir characteristics. Nonetheless, the underlying mechanisms governing these influences remain relatively understudied. In this investigation, using the Chang-7 block of the Changqing Oilfield as the study site, we employ EM-30 slickwater fracturing fluid to explore the effects of the drag-reducing agent concentration, imbibition temperature, core permeability, and core fracture development on spontaneous imbibition. An elevated drag-reducing agent concentration is observed to diminish the degree of medium and small pore utilization. Furthermore, higher temperatures and an augmented permeability enhance the fluid flow properties, thereby contributing to an increased utilization rate across all pore sizes. Reduced fracture development results in a lower fluid utilization across diverse pore types. This study deepens our understanding of the pivotal factors affecting spontaneous imbibition in tight reservoirs following fracturing. The findings act as theoretical, technical, and scientific foundations for optimizing fracturing strategies in tight oil reservoir transformations.展开更多
BACKGROUND:Unsustained return of spontaneous circulation(ROSC)is a critical barrier to survival in cardiac arrest patients.This study examined whether end-tidal carbon dioxide(ETCO_(2))and pulse oximetry photoplethysm...BACKGROUND:Unsustained return of spontaneous circulation(ROSC)is a critical barrier to survival in cardiac arrest patients.This study examined whether end-tidal carbon dioxide(ETCO_(2))and pulse oximetry photoplethysmogram(POP)parameters can be used to identify unsustained ROSC.METHODS:We conducted a multicenter observational prospective cohort study of consecutive patients with cardiac arrest from 2013 to 2014.Patients’general information,ETCO_(2),and POP parameters were collected and statistically analyzed.RESULTS:The included 105 ROSC episodes(from 80 cardiac arrest patients)comprised 51 sustained ROSC episodes and 54 unsustained ROSC episodes.The 24-hour survival rate was significantly higher in the sustained ROSC group than in the unsustained ROSC group(29.2%vs.9.4%,P<0.05).The logistic regression analysis showed that the difference between after and before ROSC in ETCO_(2)(ΔETCO_(2))and the difference between after and before ROCS in area under the curve of POP(ΔAUCp)were independently associated with sustained ROSC(odds ratio[OR]=0.931,95%confi dence interval[95%CI]0.881-0.984,P=0.011 and OR=0.998,95%CI 0.997-0.999,P<0.001).The area under the receiver operating characteristic curve ofΔETCO_(2),ΔAUCp,and the combination of both to predict unsustained ROSC were 0.752(95%CI 0.660-0.844),0.883(95%CI 0.818-0.948),and 0.902(95%CI 0.842-0.962),respectively.CONCLUSION:Patients with unsustained ROSC have a poor prognosis.The combination ofΔETCO_(2) andΔAUCp showed signifi cant predictive value for unsustained ROSC.展开更多
The angiotensin-converting enzyme(ACE)inhibitory peptide NCW derived from Mizuhopecten yessoensis has been demonstrated to have significant in vivo anti-hypertensive effects,however,its anti-hypertensive mechanism is ...The angiotensin-converting enzyme(ACE)inhibitory peptide NCW derived from Mizuhopecten yessoensis has been demonstrated to have significant in vivo anti-hypertensive effects,however,its anti-hypertensive mechanism is still not fully clarified.This study established a UPLC-Q-TRAP-MS/MS-based widely targeted kidney metabolomics approach to explore the changes of kidney metabolic profiles and to clarify the antihypertensive mechanism of peptide NCW in spontaneously hypertensive rats(SHRs).Multivariate statistical analysis indicated that the kidney metabolic profiles were clearly separated between the SHR-NCW and SHRUntreated groups.A total of 85 metabolites were differentially regulated,and 16 metabolites were identified as potential kidney biomarkers,e.g.,3-hydroxybutyrate,malonic acid,deoxycytidine,and L-aspartic acid.The peptide NCW might regulate kidney metabolic disorder of SHRs to alleviate hypertension by suppressing inflammation and improving nitric oxide production under the regulation of linoleic acid metabolism,folate related pathways,synthesis and degradation of ketone bodies,pyrimidine metabolism,β-alanine metabolism,and retinal metabolism.展开更多
In this work,we present an intravascular dual-mode endoscopic system capable of both intravascular photoacoustic imaging(IVPAI)and intravascular optical coherence tomography(IVOCT)for recognizing spontaneous coronary ...In this work,we present an intravascular dual-mode endoscopic system capable of both intravascular photoacoustic imaging(IVPAI)and intravascular optical coherence tomography(IVOCT)for recognizing spontaneous coronary artery dissection(SCAD)phantoms.IVPAI provides high-resolution and high-penetration images of intramural hematoma(IMH)at different depths,so it is especially useful for imaging deep blood clots associated with imaging phantoms.IVOCT can readily visualize the double-lumen morphology of blood vessel walls to identify intimal tears.We also demonstrate the capability of this dual-mode endoscopic system using mimicking phantoms and biological samples of blood clots in ex vivo porcine arteries.The results of the experiments indicate that the combined IVPAI and IVOCT technique has the potential to provide a more accurate SCAD assessment method for clinical applications.展开更多
This is an erratum to an already published paper named“Establishment of a prediction model for prehospital return of spontaneous circulation in out-ofhospital patients with cardiac arrest”.We found errors in the aff...This is an erratum to an already published paper named“Establishment of a prediction model for prehospital return of spontaneous circulation in out-ofhospital patients with cardiac arrest”.We found errors in the affiliated institution of the authors.We apologize for our unintentional mistake.Please note,these changes do not affect our results.展开更多
BACKGROUND Spontaneous coronary artery rupture(SCAR)is a rare and life-threatening complication after lung cancer surgery.We present a case of SCAR following left upper lobectomy,successfully managed through emergency...BACKGROUND Spontaneous coronary artery rupture(SCAR)is a rare and life-threatening complication after lung cancer surgery.We present a case of SCAR following left upper lobectomy,successfully managed through emergency thoracotomy and coronary artery ligation.CASE SUMMARY A 61-year-old male patient underwent left upper lobectomy and mediastinal lymph node dissection for lung cancer.The surgery was performed using singleport video-assisted thoracoscopic surgery,and there were no observed complications during the procedure.However,19 h after surgery,the patient experienced chest discomfort and subsequently developed severe symptoms,including nausea,vomiting,and a drop in blood pressure.Urgent measures were taken,leading to the diagnosis of SCAR.The patient underwent emergency thoracotomy and coronary artery ligation,successfully stopping the bleeding and stabilizing the condition.Despite postoperative complications,the patient made a successful recovery and was discharged from the hospital.CONCLUSION SCAR is a rare but life-threatening complication following lung cancer surgery.Immediate thoracotomy has been shown to be a life-saving measure,while stenting is not the preferred initial approach.展开更多
Background: The absence of a safe and effective therapy for recurrent spontaneous abortion due to a maternofetal failure in immunological tolerance remains an intractable clinical obstacle for surgeons. Recently, trad...Background: The absence of a safe and effective therapy for recurrent spontaneous abortion due to a maternofetal failure in immunological tolerance remains an intractable clinical obstacle for surgeons. Recently, traditional Chinese medicine has become a feasible alternative for certain diseases, including recurrent spontaneous abortion. However, because of the complex composition of the traditional Chinese medicine formula, its action mechanism remains unclear. Methods: We selected two isolated active ingredients (RAMP and baicalin) from the traditional Chinese medicine formula and used an abortion-prone CBA/J × DBA/2 model to simulate human RSA and compared the changes in fetal resorption rate, Treg cell percentage, and relevant cytokines before and after combination therapy. In addition, The mechanisms were preliminarily discussed using in vitro differentiation models. Results: In CBA/J × DBA/2 abortion-prone mice, the combination therapy resulted in a lower embryo resorption rate compared to that obtained with individual delivery of either RAMP or baicalin, thereby playing an embryo-protective role through the increase in Treg cells for the maintenance of maternal-fetal immune tolerance. In in vitro primary cell differentiation experiments, the concentration of Treg cells significantly increased from 11% to 17.9% after the combination therapy compared to that of the single administration group. Conclusion: the synergistic effects of RAMP and baicalin were responsible for Treg differentiation. The present study provides a solid basis for improving the applicability of traditional Chinese herbs in the treatment of recurrent spontaneous abortion.展开更多
Broad ligament hematoma is typically seen during cesarean section due to rupture of branches of uterine and vaginal vessels and it’s rare to be seen post-normal vaginal delivery. Addressing puerperal hematomas postpa...Broad ligament hematoma is typically seen during cesarean section due to rupture of branches of uterine and vaginal vessels and it’s rare to be seen post-normal vaginal delivery. Addressing puerperal hematomas postpartum presents considerable challenges for obstetric care providers. While hematomas such as those affecting the vulva, vulvovaginal region, or paravaginal area are frequently encountered, retroperitoneal hematomas are rare and notably pose a greater risk to the life of the patient. The medical literature contains scant case reports on retroperitoneal hematomas, with no consensus on a definitive treatment approach. Pelvic arterial embolization has emerged as both a sensible and increasingly preferred method for treating these hematomas recently, but its application is contingent upon the patient maintaining hemodynamic stability and the availability of a specialized interventional embolization unit. In our case, we are presenting a very rare case of a 31-year-old primigravida female with a history of in vitro fertilization pregnancy. She delivered a normal vaginal delivery at 31 weeks gestation. Unfortunately, she experienced multiple complications intrapartum, including preeclampsia and placental abruption. These complications increased her risk of developing a broad ligament hematoma.展开更多
Spontaneous intracerebral haemorrhage (sICH) is characterised by bleeding within the brain parenchyma, without any accompanying vascular malformation, parenchymal abnormality or coagulation disorder. The study aimed t...Spontaneous intracerebral haemorrhage (sICH) is characterised by bleeding within the brain parenchyma, without any accompanying vascular malformation, parenchymal abnormality or coagulation disorder. The study aimed to depict the management of sICH at the University Hospital of Brazzaville (UHB). It was an observational, descriptive, and cross-sectional analysis. Data collection was conducted retrospectively, covering the period from January 1, 2020 to August 31, 2022, spanning two years and eight months. The study examined socio-demographic, diagnostic, therapeutic, and evolutionary variables. We included 274 cases. We observed 160 men (58.4%) and 114 women (41.6%), resulting in a sex ratio of 1.4. The mean age was 55.3 ± 11.4 years, with ages ranging from 31 to 93 years. The detection of sICH was typically a result of experiencing motor deficits (59.5%) or disorders of consciousness (37.2%). The weightiness of one half of the body was the most common reason for seeking medical advice. Hematoma was capsulo-lenticular in 159 cases (58%) and capsulo-thalamic in 63 cases (23%). Hematomas were <30 ml in 162 cases (59.1%) and >30 ml in 112 cases (40.9%), and associated with hydrocephalus in 11.7% of cases. Conservative medical treatment was administered in 257 cases (94.2%) while surgical treatment was performed in 16 cases (5.8%). The surgical techniques used were external ventricular drainage (EVD) in 2 cases, ventriculo-peritoneal shunt in 5 cases, and hematoma evacuation in 10 cases. Death occurred before the 7th day of hospitalisation in 73 cases (57.8%) and after in 46 cases (42.2%). The median time to death was four days (Q1 = 2 days;Q3 = 7 days), with extremes of 0 and 216 days. .展开更多
Background: Premature cervical softening and shortening may be considered an early mechanical failure that predispose to preterm birth. Purpose: This study aims to explore the applicability of an innovative cervical t...Background: Premature cervical softening and shortening may be considered an early mechanical failure that predispose to preterm birth. Purpose: This study aims to explore the applicability of an innovative cervical tactile ultrasound approach for predicting spontaneous preterm birth (sPTB). Materials and Methods: Eligible participants were women with low-risk singleton pregnancies in their second trimester, enrolled in this prospective observational study. A Cervix Monitor (CM) device was designed with a vaginal probe comprising four tactile sensors and a single ultrasound transducer operating at 5 MHz. The probe enabled the application of controllable pressure to the external cervical surface, facilitating the acquisition of stress-strain data from both anterior and posterior cervical sectors. Gestational age at delivery was recorded and compared against cervical elasticity. Results: CM examination data were analyzed for 127 women at 24<sup>0/7</sup> - 28<sup>6/7</sup> gestational weeks. sPTB was observed in 6.3% of the cases. The preterm group exhibited a lower average cervical stress-to-strain ratio (elasticity) of 0.70 ± 0.26 kPa/mm compared to the term group’s 1.63 ± 0.65 kPa/mm with a p-value of 1.1 × 10<sup>−</sup><sup>4</sup>. Diagnostic accuracy for predicting spontaneous preterm birth based solely on cervical elasticity data was found to be 95.0% (95% CI, 88.5 - 100.0). Conclusion: These findings suggest that measuring cervical elasticity with the designed tactile ultrasound probe has the potential to predict spontaneous preterm birth in a cost-effective manner.展开更多
Spontaneous Tumor Lysis Syndrome (STLS) is a rare oncologic condition caused by the breakdown of neoplastic tissue in the absence of traditional anti-tumor therapy. It is postulated that cancers with rapidly dividing ...Spontaneous Tumor Lysis Syndrome (STLS) is a rare oncologic condition caused by the breakdown of neoplastic tissue in the absence of traditional anti-tumor therapy. It is postulated that cancers with rapidly dividing cells lead to increased cell turnover which exceeds the kidneys’ ability to adequately filtrate by-products of cellular breakdown (i.e., phosphate, potassium, anduric acid), leading to end organ damage. It has been reported in the past that kidney failure is a sequelae of Tumor Lysis Syndrome (TLS), but there have been no reports that demonstrate acute kidney injury (AKI) preceding TLS. The case presented here demonstrates TLS in a patient with no formal cancer diagnosis, who had received no chemotherapy or radiation that was precipitated by an iatrogenic AKI with chlorthalidone and ibuprofen. This unusual pattern of AKI preceding STLS may provide insight into the pathophysiology of the condition and could possibly lead to greater understanding of this phenomenon.展开更多
BACKGROUND Out-of-hospital cardiac arrest(OHCA)is a leading cause of death worldwide.AIM To explore factors influencing prehospital return of spontaneous circulation(P-ROSC)in patients with OHCA and develop a nomogram...BACKGROUND Out-of-hospital cardiac arrest(OHCA)is a leading cause of death worldwide.AIM To explore factors influencing prehospital return of spontaneous circulation(P-ROSC)in patients with OHCA and develop a nomogram prediction model.METHODS Clinical data of patients with OHCA in Shenzhen,China,from January 2012 to December 2019 were retrospectively analyzed.Least absolute shrinkage and selection operator(LASSO)regression and multivariate logistic regression were applied to select the optimal factors predicting P-ROSC in patients with OHCA.A nomogram prediction model was established based on these influencing factors.Discrimination and calibration were assessed using receiver operating charac-teristic(ROC)and calibration curves.Decision curve analysis(DCA)was used to evaluate the model’s clinical utility.RESULTS Among the included 2685 patients with OHCA,the P-ROSC incidence was 5.8%.LASSO and multivariate logistic regression analyses showed that age,bystander cardiopulmonary resuscitation(CPR),initial rhythm,CPR duration,ventilation mode,and pathogenesis were independent factors influencing P-ROSC in these patients.The area under the ROC was 0.963.The calibration plot demonstrated that the predicted P-ROSC model was concordant with the actual P-ROSC.The good clinical usability of the prediction model was confirmed using DCA.CONCLUSION The nomogram prediction model could effectively predict the probability of P-ROSC in patients with OHCA.展开更多
The physical and chemical properties of the air-dried residual coal after soaking in the goaf will change,resulting in an increase in its spontaneous combustion tendency.This study aimed to look into the features and ...The physical and chemical properties of the air-dried residual coal after soaking in the goaf will change,resulting in an increase in its spontaneous combustion tendency.This study aimed to look into the features and mechanism of soaked-dried coal's spontaneous combustion.Five samples of coal were dried to various degrees,and the weight loss features during thermal processing were examined.Based on this,the pore structure and chemical structure characteristics of the coal samples with the highest tendency to spontaneous combustion were quantitatively examined,and the mechanism by which soaking-drying afected the spontaneous combustion heating process of the remaining coal in goaf was investigated in turn.The results show that T1 decreases with the increase of drying time,T2–T6 shows a fuctuating change,and the ignition activation energy of 36-S-Coal is smaller than that of other coal samples.The pore type of 36-S-Coal changes from a oneend closed impermeable pore to an open pore,and the pore group area is large.During the 36 h drying process,the internal channels of the coal were dredged,and a large number of gravels and minerals were precipitated from the pores with the air fow.A large number of gravels were around the pores to form a surface structure that was easy to adsorb various gases.Furthermore,infrared spectroscopy was used to analyze the two coal samples.It was found that soaking and drying did not change the functional group types of coal samples,but the fatty chain degree of 36-S-Coal was reduced to 1.56.It shows that the aliphatic chain structure of coal is changed after 36 h of drying after 30 days of soaking,which leads to the continuous shedding of aliphatic chain branches of residual coal,and the skeleton of coal is looser,which makes the low-temperature oxidation reaction of 36-S-Coal easier.Based on the above results,the coal-oxygen composite mechanism of water-immerseddried coal is obtained,and it is considered that the key to the spontaneous combustion oxidation process of coal is to provide oxygen atoms and accelerate the formation of peroxides.展开更多
Animal expe riments have shown that injectable collagen scaffold with human umbilical cord-derived mesenchymal stem cells can promote recovery from spinal cord injury.To investigate whether injectable collagen scaffol...Animal expe riments have shown that injectable collagen scaffold with human umbilical cord-derived mesenchymal stem cells can promote recovery from spinal cord injury.To investigate whether injectable collagen scaffold with human umbilical cord-derived mesenchymal stem cells can be used to treat spontaneous intracerebral hemorrhage,this non-randomized phase I clinical trial recruited patients who met the inclusion criteria and did not meet the exclusion crite ria of spontaneous intracerebral hemorrhage treated in the Characteristic Medical Center of Chinese People’s Armed Police Force from May 2016 to December 2020.Patients were divided into three groups according to the clinical situation and patient benefit:control(n=18),human umbilical cord-derived mesenchymal stem cells(n=4),and combination(n=8).The control group did not receive any transplantation.The human umbilical cord-derived mesenchymal stem cells group received human umbilical cord-derived mesenchymal stem cell transplantation.The combination group received injectable collagen scaffold with human umbilical cord-derived mesenchymal stem cells.Patients who received injectable collagen scaffold with human umbilical cord-derived mesenchymal stem cells had more remarkable improvements in activities of daily living and cognitive function and smaller foci of intra cerebral hemorrhage-related encephalomalacia.Severe adve rse events associated with cell transplantation were not observed.Injectable collagen scaffold with human umbilical cord-derived mesenchymal stem cells appears to have great potential treating spontaneous intracerebral hemorrhage.展开更多
Shale oil can be extracted from shale by using interconnected pore networks.The migration of hydrocarbon molecules within the shale is controlled by pore connectivity.However,assessing the pore connectivity of shale o...Shale oil can be extracted from shale by using interconnected pore networks.The migration of hydrocarbon molecules within the shale is controlled by pore connectivity.However,assessing the pore connectivity of shale oil reservoirs is uncommon.To characterize pore connectivity and clarify its controlling factors,this study used spontaneous imbibition(SI)combined with nuclear magnetic resonance(NMR)T_(2)and T_(1)-T_(2)technologies on shale oil reservoirs selected from the Shahejie Formation in the Dongying Sag,Bohai Bay Basin.According to the findings,the SI processes of shales include fast-rising,slow-rising,and stable stages.The fast-rising stage denotes pore connectivity.The shales studied have poor connectivity,with lower imbibition slopes and connected porosity ratios,but large effective tortuosity.During the SI process,micropores have the highest imbibition saturation,followed by mesopores and macropores.Furthermore,n-dodecane ingested into micropores appears primarily as adsorbed,whereas n-dodecane appears primarily as free states in mesopores and macropores during the SI process.The pore connectivity of the shales under study is primarily controlled by inorganic minerals.Quartz and feldspar develop large and regular pores,resulting in better pore connectivity,whereas clay minerals and calcite with plenty of complex intragranular pores do not.Organic matter negatively influences pore connectivity because the dissolution of calcite by organic acid produced during hydrocarbon generation leads to a more complex and heterogeneous pore structure.This study sheds light on the pore connectivity and controlling factors of the shale oil reservoir and aids in the understanding of shale oil mobility.展开更多
The spontaneous emission property ofΛ-type three-level atom driven by the bichromatic field in the anisotropic double-band photonic crystal is calculated by n-times iteration method.The influence of different paramet...The spontaneous emission property ofΛ-type three-level atom driven by the bichromatic field in the anisotropic double-band photonic crystal is calculated by n-times iteration method.The influence of different parameters on atomic spontaneous emission is studied,and the phenomena of atomic spontaneous emission are explained in the dressed state representation.It is found that the spontaneous emission spectra of the atom driven by the bichromatic field presents a multi-peak comb structure.The position of the emission peak is determined by the initial state of the atom,and the interval between the neighboring emission peaks is the detuningδof the bichromatic field.When the ratio between Rabi frequency intensity and the detuningδof the bichromatic field remains unchanged,the intensity of each emitted peak remains invariant.The spontaneously emitted peak can be annihilated in the band gap and enhanced near the band edge in the anisotropic photonic crystals.Meanwhile,we also observe the fluorescence quenching phenomenon in the spontaneous emission spectra.The research in this paper provides the theoretical guidance for the control of atomic spontaneous emission.展开更多
BACKGROUND Titanium mesh cranioplasty is often performed after decompressive craniectomy.Spontaneous fracture of the titanium prosthesis is an extremely rare postoperative complication.Here,we report a 10-year-old boy...BACKGROUND Titanium mesh cranioplasty is often performed after decompressive craniectomy.Spontaneous fracture of the titanium prosthesis is an extremely rare postoperative complication.Here,we report a 10-year-old boy who presented with a spontaneous fracture of titanium mesh without antecedent head trauma.CASE SUMMARY A 10-year-old boy presented with a 1-wk history of a tender bulge over the left temporo-parieto-occipital scalp.He had undergone a temporo-parieto-occipital titanium mesh cranioplasty 26 mo previously.He denied antecedent head trauma.Computerized tomography disclosed a perpendicular fissure in the titanium mesh,suggesting a diagnosis of spontaneous titanium mesh fracture.He underwent a second temporo-parieto-occipital cranioplasty and made an uneventful recovery.Three-dimensional modeling and finite element analyses were used to explore potential risk factors of titanium mesh fracture.CONCLUSION We report a case of spontaneous fracture of a titanium mesh cranioplasty implant.The current case and literature review indicate that titanium mesh implants should be well-anchored to the base of bony defects to prevent fatigue-induced fractures.展开更多
文摘An increase in methane,spontaneous fire and bumping hazards in Polish hard coal mines,observed in the last two decades,led to the need to elaborate the tools allowing proper selection of a range of preventive measures to fight them at the stage of designing coal extraction.Designing the production of a coal seams in the conditions of associated methane and spontaneous fires hazards in Polish hard coal mines requires elaboration of the design standards for coal panels in gassy coal seams.This paper presents the guidelines on how to design production in the conditions of associated methane and spontaneous fire hazards.Presented tools and methodology since the very first research were many times verified by daily mining operations in the conditions of associated methane and spontaneous fire hazards,which confirms their significant contribution to the development of safe and economical mining operations.
基金supported by China Natural Science Foundation(Grant No.52274053)Beijing Natural Science Foundation(Grant No.3232028)Open Fund of State Key Laboratory of Offshore Oil Exploitation(Grant No.CCL2021RCPS0515KQN)。
文摘Spontaneous imbibition(SI)is an important mechanism for enhancing oil recovery in low-permeability reservoirs.Due to the strong heterogeneity,and the non-Darcy flow,the construction of SI model for lowpermeability reservoirs is extremely challenging.Commonly,traditional SI models based on single or averaged capillary tortuosity ignore the influence of heterogeneity of pore seepage channels and the threshold pressure(TP)on imbibition.Therefore,in this work,based on capillary model and fractal theory,a mathematical model of characterizing SI considering heterogeneity of pore seepage channels is established.On this basis,the threshold pressure was introduced to determine the pore radius at which the wetted phase can displace oil.The proposed new SI model was verified by imbibition experimental data.The study shows that for weakly heterogeneous cores with permeability of 0-1 m D,the traditional SI model can characterize the imbibition process relatively accurately,and the new imbibition model can increase the coefficient of determination by 1.05 times.However,traditional model has serious deviations in predicting the imbibition recovery for cores with permeability of 10-50 m D.The new SI model coupling with heterogeneity of pore seepage channels and threshold pressure effectively solves this problem,and the determination coefficient is increased from 0.344 to 0.922,which is increased by2.68 times.For low-permeability reservoirs,the production of the oil in transitional pores(0.01-0.1μm)and mesopores(0.1-1μm)significantly affects the imbibition recovery,as the research shows that when the heterogeneity of pore seepage channels is ignored,the oil recovery in transitional pores and mesopores decreases by 7.54%and 4.26%,respectively.Sensitivity analysis shows that increasing interfacial tension,decreasing contact angle,oil-water viscosity ratio and threshold pressure will increase imbibition recovery.In addition,there are critical values for the influence of these factors on the imbibition recovery,which provides theoretical support for surfactant optimization.
基金Funded by National Natural Science Foundation of China (No.52074218)。
文摘A hydrotalcite(layered double hydroxide, LDH) inhibitor which is suitable for the whole process of coal spontaneous combustion and a LDH inhibitor containing rare earth lanthanum elements were prepared. The inhibition effect and mechanism were analyzed by scanning electron microscopy(SEM),X-ray diffraction(XRD), thermal performance analysis, in-situ diffuse reflectance infrared spectroscopy and temperature-programmed experiment. The results have shown that the inhibitor containing lanthanum can play a good inhibitory role in every stage of coal oxidation. During the slow oxidation of coal samples, the inhibitor containing lanthanum ions can slow down the oxidation process of coal and increase the initial temperature of coal spontaneous combustion. At the same time, because the hydroxyl groups in LDHs are connected with-COO-groups on the coal surface through hydrogen bonds, the stability of coal is improved. With the increase of temperature, LDHs can remove interlayer water molecules and reduce the surface temperature of coal. CO release rate of coal samples decreases significantly after adding inhibitor containing lanthanum element, and the maximum inhibition rate of the inhibitor is 58.1%.
基金The authors sincerely appreciate the financial support from the National Natural Science Foundation of China(No.52074279,51874261).
文摘Slickwater fracturing fluids have gained widespread application in the development of tight oil reservoirs. After the fracturing process, the active components present in slickwater can directly induce spontaneous imbibition within the reservoir. Several variables influence the eventual recovery rate within this procedure, including slickwater composition, formation temperature, degree of reservoir fracture development, and the reservoir characteristics. Nonetheless, the underlying mechanisms governing these influences remain relatively understudied. In this investigation, using the Chang-7 block of the Changqing Oilfield as the study site, we employ EM-30 slickwater fracturing fluid to explore the effects of the drag-reducing agent concentration, imbibition temperature, core permeability, and core fracture development on spontaneous imbibition. An elevated drag-reducing agent concentration is observed to diminish the degree of medium and small pore utilization. Furthermore, higher temperatures and an augmented permeability enhance the fluid flow properties, thereby contributing to an increased utilization rate across all pore sizes. Reduced fracture development results in a lower fluid utilization across diverse pore types. This study deepens our understanding of the pivotal factors affecting spontaneous imbibition in tight reservoirs following fracturing. The findings act as theoretical, technical, and scientific foundations for optimizing fracturing strategies in tight oil reservoir transformations.
基金supported by National Natural Science Foundation of China General Program (82172179)Mathematics Tianyuan Fund (12126604)Central High-level Hospital Clinical Research Project (2022-PUMCH-B-110)
文摘BACKGROUND:Unsustained return of spontaneous circulation(ROSC)is a critical barrier to survival in cardiac arrest patients.This study examined whether end-tidal carbon dioxide(ETCO_(2))and pulse oximetry photoplethysmogram(POP)parameters can be used to identify unsustained ROSC.METHODS:We conducted a multicenter observational prospective cohort study of consecutive patients with cardiac arrest from 2013 to 2014.Patients’general information,ETCO_(2),and POP parameters were collected and statistically analyzed.RESULTS:The included 105 ROSC episodes(from 80 cardiac arrest patients)comprised 51 sustained ROSC episodes and 54 unsustained ROSC episodes.The 24-hour survival rate was significantly higher in the sustained ROSC group than in the unsustained ROSC group(29.2%vs.9.4%,P<0.05).The logistic regression analysis showed that the difference between after and before ROSC in ETCO_(2)(ΔETCO_(2))and the difference between after and before ROCS in area under the curve of POP(ΔAUCp)were independently associated with sustained ROSC(odds ratio[OR]=0.931,95%confi dence interval[95%CI]0.881-0.984,P=0.011 and OR=0.998,95%CI 0.997-0.999,P<0.001).The area under the receiver operating characteristic curve ofΔETCO_(2),ΔAUCp,and the combination of both to predict unsustained ROSC were 0.752(95%CI 0.660-0.844),0.883(95%CI 0.818-0.948),and 0.902(95%CI 0.842-0.962),respectively.CONCLUSION:Patients with unsustained ROSC have a poor prognosis.The combination ofΔETCO_(2) andΔAUCp showed signifi cant predictive value for unsustained ROSC.
基金supported by the National Natural Science Foundation of China(No.31901635)。
文摘The angiotensin-converting enzyme(ACE)inhibitory peptide NCW derived from Mizuhopecten yessoensis has been demonstrated to have significant in vivo anti-hypertensive effects,however,its anti-hypertensive mechanism is still not fully clarified.This study established a UPLC-Q-TRAP-MS/MS-based widely targeted kidney metabolomics approach to explore the changes of kidney metabolic profiles and to clarify the antihypertensive mechanism of peptide NCW in spontaneously hypertensive rats(SHRs).Multivariate statistical analysis indicated that the kidney metabolic profiles were clearly separated between the SHR-NCW and SHRUntreated groups.A total of 85 metabolites were differentially regulated,and 16 metabolites were identified as potential kidney biomarkers,e.g.,3-hydroxybutyrate,malonic acid,deoxycytidine,and L-aspartic acid.The peptide NCW might regulate kidney metabolic disorder of SHRs to alleviate hypertension by suppressing inflammation and improving nitric oxide production under the regulation of linoleic acid metabolism,folate related pathways,synthesis and degradation of ketone bodies,pyrimidine metabolism,β-alanine metabolism,and retinal metabolism.
基金funding from the National Natural Science Foundation of China(NSFC)under grants 61627827,61705068the Natural Science Foundation of Fujian Province 2021J01813the Fujian Medical University Research Foundation of Talented Scholars XRCZX2021004.
文摘In this work,we present an intravascular dual-mode endoscopic system capable of both intravascular photoacoustic imaging(IVPAI)and intravascular optical coherence tomography(IVOCT)for recognizing spontaneous coronary artery dissection(SCAD)phantoms.IVPAI provides high-resolution and high-penetration images of intramural hematoma(IMH)at different depths,so it is especially useful for imaging deep blood clots associated with imaging phantoms.IVOCT can readily visualize the double-lumen morphology of blood vessel walls to identify intimal tears.We also demonstrate the capability of this dual-mode endoscopic system using mimicking phantoms and biological samples of blood clots in ex vivo porcine arteries.The results of the experiments indicate that the combined IVPAI and IVOCT technique has the potential to provide a more accurate SCAD assessment method for clinical applications.
文摘This is an erratum to an already published paper named“Establishment of a prediction model for prehospital return of spontaneous circulation in out-ofhospital patients with cardiac arrest”.We found errors in the affiliated institution of the authors.We apologize for our unintentional mistake.Please note,these changes do not affect our results.
文摘BACKGROUND Spontaneous coronary artery rupture(SCAR)is a rare and life-threatening complication after lung cancer surgery.We present a case of SCAR following left upper lobectomy,successfully managed through emergency thoracotomy and coronary artery ligation.CASE SUMMARY A 61-year-old male patient underwent left upper lobectomy and mediastinal lymph node dissection for lung cancer.The surgery was performed using singleport video-assisted thoracoscopic surgery,and there were no observed complications during the procedure.However,19 h after surgery,the patient experienced chest discomfort and subsequently developed severe symptoms,including nausea,vomiting,and a drop in blood pressure.Urgent measures were taken,leading to the diagnosis of SCAR.The patient underwent emergency thoracotomy and coronary artery ligation,successfully stopping the bleeding and stabilizing the condition.Despite postoperative complications,the patient made a successful recovery and was discharged from the hospital.CONCLUSION SCAR is a rare but life-threatening complication following lung cancer surgery.Immediate thoracotomy has been shown to be a life-saving measure,while stenting is not the preferred initial approach.
基金the National Natural Science Foundation of China(81973221)National Natural Science Foundation for Young Scientists of China(81603647)+2 种基金the Women and Children Health Talent Project of Jiangsu Province(FRC201785)the Chinese Clinical Medicine Innovation Center of Obstetrics,Gynecology,and Reproduction in Jiangsu Province(ZX202102)the Women and Children Health Science Foundation of Jiangsu Province(F202206).
文摘Background: The absence of a safe and effective therapy for recurrent spontaneous abortion due to a maternofetal failure in immunological tolerance remains an intractable clinical obstacle for surgeons. Recently, traditional Chinese medicine has become a feasible alternative for certain diseases, including recurrent spontaneous abortion. However, because of the complex composition of the traditional Chinese medicine formula, its action mechanism remains unclear. Methods: We selected two isolated active ingredients (RAMP and baicalin) from the traditional Chinese medicine formula and used an abortion-prone CBA/J × DBA/2 model to simulate human RSA and compared the changes in fetal resorption rate, Treg cell percentage, and relevant cytokines before and after combination therapy. In addition, The mechanisms were preliminarily discussed using in vitro differentiation models. Results: In CBA/J × DBA/2 abortion-prone mice, the combination therapy resulted in a lower embryo resorption rate compared to that obtained with individual delivery of either RAMP or baicalin, thereby playing an embryo-protective role through the increase in Treg cells for the maintenance of maternal-fetal immune tolerance. In in vitro primary cell differentiation experiments, the concentration of Treg cells significantly increased from 11% to 17.9% after the combination therapy compared to that of the single administration group. Conclusion: the synergistic effects of RAMP and baicalin were responsible for Treg differentiation. The present study provides a solid basis for improving the applicability of traditional Chinese herbs in the treatment of recurrent spontaneous abortion.
文摘Broad ligament hematoma is typically seen during cesarean section due to rupture of branches of uterine and vaginal vessels and it’s rare to be seen post-normal vaginal delivery. Addressing puerperal hematomas postpartum presents considerable challenges for obstetric care providers. While hematomas such as those affecting the vulva, vulvovaginal region, or paravaginal area are frequently encountered, retroperitoneal hematomas are rare and notably pose a greater risk to the life of the patient. The medical literature contains scant case reports on retroperitoneal hematomas, with no consensus on a definitive treatment approach. Pelvic arterial embolization has emerged as both a sensible and increasingly preferred method for treating these hematomas recently, but its application is contingent upon the patient maintaining hemodynamic stability and the availability of a specialized interventional embolization unit. In our case, we are presenting a very rare case of a 31-year-old primigravida female with a history of in vitro fertilization pregnancy. She delivered a normal vaginal delivery at 31 weeks gestation. Unfortunately, she experienced multiple complications intrapartum, including preeclampsia and placental abruption. These complications increased her risk of developing a broad ligament hematoma.
文摘Spontaneous intracerebral haemorrhage (sICH) is characterised by bleeding within the brain parenchyma, without any accompanying vascular malformation, parenchymal abnormality or coagulation disorder. The study aimed to depict the management of sICH at the University Hospital of Brazzaville (UHB). It was an observational, descriptive, and cross-sectional analysis. Data collection was conducted retrospectively, covering the period from January 1, 2020 to August 31, 2022, spanning two years and eight months. The study examined socio-demographic, diagnostic, therapeutic, and evolutionary variables. We included 274 cases. We observed 160 men (58.4%) and 114 women (41.6%), resulting in a sex ratio of 1.4. The mean age was 55.3 ± 11.4 years, with ages ranging from 31 to 93 years. The detection of sICH was typically a result of experiencing motor deficits (59.5%) or disorders of consciousness (37.2%). The weightiness of one half of the body was the most common reason for seeking medical advice. Hematoma was capsulo-lenticular in 159 cases (58%) and capsulo-thalamic in 63 cases (23%). Hematomas were <30 ml in 162 cases (59.1%) and >30 ml in 112 cases (40.9%), and associated with hydrocephalus in 11.7% of cases. Conservative medical treatment was administered in 257 cases (94.2%) while surgical treatment was performed in 16 cases (5.8%). The surgical techniques used were external ventricular drainage (EVD) in 2 cases, ventriculo-peritoneal shunt in 5 cases, and hematoma evacuation in 10 cases. Death occurred before the 7th day of hospitalisation in 73 cases (57.8%) and after in 46 cases (42.2%). The median time to death was four days (Q1 = 2 days;Q3 = 7 days), with extremes of 0 and 216 days. .
文摘Background: Premature cervical softening and shortening may be considered an early mechanical failure that predispose to preterm birth. Purpose: This study aims to explore the applicability of an innovative cervical tactile ultrasound approach for predicting spontaneous preterm birth (sPTB). Materials and Methods: Eligible participants were women with low-risk singleton pregnancies in their second trimester, enrolled in this prospective observational study. A Cervix Monitor (CM) device was designed with a vaginal probe comprising four tactile sensors and a single ultrasound transducer operating at 5 MHz. The probe enabled the application of controllable pressure to the external cervical surface, facilitating the acquisition of stress-strain data from both anterior and posterior cervical sectors. Gestational age at delivery was recorded and compared against cervical elasticity. Results: CM examination data were analyzed for 127 women at 24<sup>0/7</sup> - 28<sup>6/7</sup> gestational weeks. sPTB was observed in 6.3% of the cases. The preterm group exhibited a lower average cervical stress-to-strain ratio (elasticity) of 0.70 ± 0.26 kPa/mm compared to the term group’s 1.63 ± 0.65 kPa/mm with a p-value of 1.1 × 10<sup>−</sup><sup>4</sup>. Diagnostic accuracy for predicting spontaneous preterm birth based solely on cervical elasticity data was found to be 95.0% (95% CI, 88.5 - 100.0). Conclusion: These findings suggest that measuring cervical elasticity with the designed tactile ultrasound probe has the potential to predict spontaneous preterm birth in a cost-effective manner.
文摘Spontaneous Tumor Lysis Syndrome (STLS) is a rare oncologic condition caused by the breakdown of neoplastic tissue in the absence of traditional anti-tumor therapy. It is postulated that cancers with rapidly dividing cells lead to increased cell turnover which exceeds the kidneys’ ability to adequately filtrate by-products of cellular breakdown (i.e., phosphate, potassium, anduric acid), leading to end organ damage. It has been reported in the past that kidney failure is a sequelae of Tumor Lysis Syndrome (TLS), but there have been no reports that demonstrate acute kidney injury (AKI) preceding TLS. The case presented here demonstrates TLS in a patient with no formal cancer diagnosis, who had received no chemotherapy or radiation that was precipitated by an iatrogenic AKI with chlorthalidone and ibuprofen. This unusual pattern of AKI preceding STLS may provide insight into the pathophysiology of the condition and could possibly lead to greater understanding of this phenomenon.
文摘BACKGROUND Out-of-hospital cardiac arrest(OHCA)is a leading cause of death worldwide.AIM To explore factors influencing prehospital return of spontaneous circulation(P-ROSC)in patients with OHCA and develop a nomogram prediction model.METHODS Clinical data of patients with OHCA in Shenzhen,China,from January 2012 to December 2019 were retrospectively analyzed.Least absolute shrinkage and selection operator(LASSO)regression and multivariate logistic regression were applied to select the optimal factors predicting P-ROSC in patients with OHCA.A nomogram prediction model was established based on these influencing factors.Discrimination and calibration were assessed using receiver operating charac-teristic(ROC)and calibration curves.Decision curve analysis(DCA)was used to evaluate the model’s clinical utility.RESULTS Among the included 2685 patients with OHCA,the P-ROSC incidence was 5.8%.LASSO and multivariate logistic regression analyses showed that age,bystander cardiopulmonary resuscitation(CPR),initial rhythm,CPR duration,ventilation mode,and pathogenesis were independent factors influencing P-ROSC in these patients.The area under the ROC was 0.963.The calibration plot demonstrated that the predicted P-ROSC model was concordant with the actual P-ROSC.The good clinical usability of the prediction model was confirmed using DCA.CONCLUSION The nomogram prediction model could effectively predict the probability of P-ROSC in patients with OHCA.
基金supported by the fnancial support of the General Projects of National Natural Science Foundation of China(52074156).
文摘The physical and chemical properties of the air-dried residual coal after soaking in the goaf will change,resulting in an increase in its spontaneous combustion tendency.This study aimed to look into the features and mechanism of soaked-dried coal's spontaneous combustion.Five samples of coal were dried to various degrees,and the weight loss features during thermal processing were examined.Based on this,the pore structure and chemical structure characteristics of the coal samples with the highest tendency to spontaneous combustion were quantitatively examined,and the mechanism by which soaking-drying afected the spontaneous combustion heating process of the remaining coal in goaf was investigated in turn.The results show that T1 decreases with the increase of drying time,T2–T6 shows a fuctuating change,and the ignition activation energy of 36-S-Coal is smaller than that of other coal samples.The pore type of 36-S-Coal changes from a oneend closed impermeable pore to an open pore,and the pore group area is large.During the 36 h drying process,the internal channels of the coal were dredged,and a large number of gravels and minerals were precipitated from the pores with the air fow.A large number of gravels were around the pores to form a surface structure that was easy to adsorb various gases.Furthermore,infrared spectroscopy was used to analyze the two coal samples.It was found that soaking and drying did not change the functional group types of coal samples,but the fatty chain degree of 36-S-Coal was reduced to 1.56.It shows that the aliphatic chain structure of coal is changed after 36 h of drying after 30 days of soaking,which leads to the continuous shedding of aliphatic chain branches of residual coal,and the skeleton of coal is looser,which makes the low-temperature oxidation reaction of 36-S-Coal easier.Based on the above results,the coal-oxygen composite mechanism of water-immerseddried coal is obtained,and it is considered that the key to the spontaneous combustion oxidation process of coal is to provide oxygen atoms and accelerate the formation of peroxides.
基金supported by the National Key Research and Development Plan of China,No.2016YFC1101500 (to ZS)the National Natural Science Foundation of China,Nos.11932013 and 11672332 (both to XYC)。
文摘Animal expe riments have shown that injectable collagen scaffold with human umbilical cord-derived mesenchymal stem cells can promote recovery from spinal cord injury.To investigate whether injectable collagen scaffold with human umbilical cord-derived mesenchymal stem cells can be used to treat spontaneous intracerebral hemorrhage,this non-randomized phase I clinical trial recruited patients who met the inclusion criteria and did not meet the exclusion crite ria of spontaneous intracerebral hemorrhage treated in the Characteristic Medical Center of Chinese People’s Armed Police Force from May 2016 to December 2020.Patients were divided into three groups according to the clinical situation and patient benefit:control(n=18),human umbilical cord-derived mesenchymal stem cells(n=4),and combination(n=8).The control group did not receive any transplantation.The human umbilical cord-derived mesenchymal stem cells group received human umbilical cord-derived mesenchymal stem cell transplantation.The combination group received injectable collagen scaffold with human umbilical cord-derived mesenchymal stem cells.Patients who received injectable collagen scaffold with human umbilical cord-derived mesenchymal stem cells had more remarkable improvements in activities of daily living and cognitive function and smaller foci of intra cerebral hemorrhage-related encephalomalacia.Severe adve rse events associated with cell transplantation were not observed.Injectable collagen scaffold with human umbilical cord-derived mesenchymal stem cells appears to have great potential treating spontaneous intracerebral hemorrhage.
基金This study was financially supported by the Natural Science Foundation of Shandong Province(ZR2020QD036,ZR2020QD037,and ZR2021QD072)the National Natural Science Foundation of China(41972123).
文摘Shale oil can be extracted from shale by using interconnected pore networks.The migration of hydrocarbon molecules within the shale is controlled by pore connectivity.However,assessing the pore connectivity of shale oil reservoirs is uncommon.To characterize pore connectivity and clarify its controlling factors,this study used spontaneous imbibition(SI)combined with nuclear magnetic resonance(NMR)T_(2)and T_(1)-T_(2)technologies on shale oil reservoirs selected from the Shahejie Formation in the Dongying Sag,Bohai Bay Basin.According to the findings,the SI processes of shales include fast-rising,slow-rising,and stable stages.The fast-rising stage denotes pore connectivity.The shales studied have poor connectivity,with lower imbibition slopes and connected porosity ratios,but large effective tortuosity.During the SI process,micropores have the highest imbibition saturation,followed by mesopores and macropores.Furthermore,n-dodecane ingested into micropores appears primarily as adsorbed,whereas n-dodecane appears primarily as free states in mesopores and macropores during the SI process.The pore connectivity of the shales under study is primarily controlled by inorganic minerals.Quartz and feldspar develop large and regular pores,resulting in better pore connectivity,whereas clay minerals and calcite with plenty of complex intragranular pores do not.Organic matter negatively influences pore connectivity because the dissolution of calcite by organic acid produced during hydrocarbon generation leads to a more complex and heterogeneous pore structure.This study sheds light on the pore connectivity and controlling factors of the shale oil reservoir and aids in the understanding of shale oil mobility.
基金Project supported by the Natural Science Foundation of Jilin Province of China(Grant No.20220101031JC)。
文摘The spontaneous emission property ofΛ-type three-level atom driven by the bichromatic field in the anisotropic double-band photonic crystal is calculated by n-times iteration method.The influence of different parameters on atomic spontaneous emission is studied,and the phenomena of atomic spontaneous emission are explained in the dressed state representation.It is found that the spontaneous emission spectra of the atom driven by the bichromatic field presents a multi-peak comb structure.The position of the emission peak is determined by the initial state of the atom,and the interval between the neighboring emission peaks is the detuningδof the bichromatic field.When the ratio between Rabi frequency intensity and the detuningδof the bichromatic field remains unchanged,the intensity of each emitted peak remains invariant.The spontaneously emitted peak can be annihilated in the band gap and enhanced near the band edge in the anisotropic photonic crystals.Meanwhile,we also observe the fluorescence quenching phenomenon in the spontaneous emission spectra.The research in this paper provides the theoretical guidance for the control of atomic spontaneous emission.
基金Supported by the National Natural Science Foundation of China,No.81602212Natural Science Foundation of Jiangsu Province,No.BK20161119+1 种基金Key Project supported by Medical Science and Technique Development Foundation No.YKK15139Nanjing Medical Science and Technique Development Foundation No.QRX17167.
文摘BACKGROUND Titanium mesh cranioplasty is often performed after decompressive craniectomy.Spontaneous fracture of the titanium prosthesis is an extremely rare postoperative complication.Here,we report a 10-year-old boy who presented with a spontaneous fracture of titanium mesh without antecedent head trauma.CASE SUMMARY A 10-year-old boy presented with a 1-wk history of a tender bulge over the left temporo-parieto-occipital scalp.He had undergone a temporo-parieto-occipital titanium mesh cranioplasty 26 mo previously.He denied antecedent head trauma.Computerized tomography disclosed a perpendicular fissure in the titanium mesh,suggesting a diagnosis of spontaneous titanium mesh fracture.He underwent a second temporo-parieto-occipital cranioplasty and made an uneventful recovery.Three-dimensional modeling and finite element analyses were used to explore potential risk factors of titanium mesh fracture.CONCLUSION We report a case of spontaneous fracture of a titanium mesh cranioplasty implant.The current case and literature review indicate that titanium mesh implants should be well-anchored to the base of bony defects to prevent fatigue-induced fractures.