Optimal Design and Experimental Verification of Low Radiation Noise of Gearbox

Reducing the radiated noise of a gearbox is a difficult problem in aviation,navigation,machinery,and other fields.Structural improvement is the main means of noise reduction for a gearbox,and it is realized primarily through contribution analysis and structure optimization.However,these approaches have certain limitations.In this study,a low-noise design method for a gearbox that combines the two approaches is proposed,and experimental verification is performed.First,a finite element/boundary element model is established using a single-stage herringbone gearbox.Considering the vibration excitation of the gear system,the radiation noise of a single-stage gearbox is predicted based on the modal acoustic transfer vector(MATV)method.Subsequently,the maximum field point of the radiated noise is determined,and the acoustic transfer vector(ATV)analysis and modal acoustic contribution(MAC)analysis are conducted to determine the region that contributes significantly to the radiated noise of the field point.The optimization region is selected through the panel acoustic contribution(PAC)analysis.Next,to reduce the normal speed in the optimization region,topology optimization is performed.According to the topology optimization results,four different noise reduction structures are added to the gearbox,and the low-noise optimization models are established respectively.Finally,by measuring the radiated noise of the gearbox before and after optimization under a given working condition,the validity of the radiated noise prediction method and the low-noise optimization design method are verified by comparing the simulation and experimental data.A comparison of the four optimization models proves that the noise reduction effect can be achieved only by adding a noise reduction structure to the center of the density nephogram.

Prediction of multifaceted asymmetric radiation from the edge movement in density-limit disruptive plasmas on Experimental Advanced Superconducting Tokamak using random forest

Multifaceted asymmetric radiation from the edge(MARFE) movement which can cause density limit disruption is often encountered during high density operation on many tokamaks. Therefore, identifying and predicting MARFE movement is meaningful to mitigate or avoid density limit disruption for the steady-state high-density plasma operation. A machine learning method named random forest(RF) has been used to predict the MARFE movement based on the density ramp-up experiment in the 2022’s first campaign of Experimental Advanced Superconducting Tokamak(EAST). The RF model shows that besides Greenwald fraction which is the ratio of plasma density and Greenwald density limit, dβp/dt,H98and d Wmhd/dt are relatively important parameters for MARFE-movement prediction. Applying the RF model on test discharges, the test results show that the successful alarm rate for MARFE movement causing density limit disruption reaches ~ 85% with a minimum alarm time of ~ 40 ms and mean alarm time of ~ 700 ms. At the same time, the false alarm rate for non-disruptive and non-density-limit disruptive discharges can be kept below 5%. These results provide a reference to the prediction of MARFE movement in high density plasmas, which can help the avoidance or mitigation of density limit disruption in future fusion reactors.

Experimental observation of rat's early-stage fracture healing with different kinds of nerve injuries

To investigate the impact of different kinds of nerve injuries of early-stage fracture healing.Methods Three groups of rats were included in the experiment among which group 1 was inflicted with femoral fracture and T10 spinal cord transsection (SCI),group 2 was inflicted with femoral and peripheral nerve resection (PNR),and group 3 with simple femoral fracture as control group.Two weeks after operation the femoral bones were collected for X-ray checking and 2 more weeks later X-ray checking was performed again followed by pathomorphologic exams.Results X-ray result showed no massive calluses in the bones in the 2nd week postoperatively,while in the 4th week,callus appeared with larger size in group 3 than that of group 1 and with smaller size than that of group 2.It was the same with the result of pathomorphologic examining.Cortical bone bridges between fracture point and osteiod were also found in group 2 and there were less normal blood vessels and worse bone remodeling than that of group 3.There were relatively immature calluses with more fibroblast-like cells and disordered bone structure in group 2.Group 3 showed normal healing process and callus structure.Conclusion Early-stage bone fracture healing can be influenced significantly by different kinds of nerve injuries.6 refs,6 figs.

Prevention and treatment of radiation-induced lung injury by hydroxypiperquin phosphate: a clinical and experimental study

Objective: To evaluate the hydroxypiperquin phosphate (HPQP) as a modifier of radiation-induced injury in human and rat lungs. Methods: Sixty-five patients with lung cancer treated with conventional radiotherapy were divided into 2 groups randomly: Thirty cases were treated with HPQP and the others were in a control group. The changes of X - ray manifestation before, after and during taking drug were compared. An animal model of radiation-induced fibrosis of lungs was also established. Hydroxyproling (HP) content in lung tissue and the pathological changes in rat lungs were checked with microscope and electron microscope after 4 months and 6 months respectively. Results: The changes of lung X-ray manifestation in treatment group were much lighter than that in control group. The HP content and the change of pathology in the lungs of those rats with HPQP treatment were obviously less than that in control group. Conclusion: HPQP plays an important role in prevention and treatment of radiation-induced injury in lungs.

Antioxidants in experimental ischemia-reperfusion injury of the testis: Where are we heading towards?

Testicular torsion(TT) is a medical emergency that primary affects newborns and young adolescents.It causes testicular injury due to the torsion of the spermatic cord and its components, initially in the venous blood flow and finally in the arterial blood flow.Prompt diagnosis and early surgical management are necessary in managing this urgent situation.The process of the pathophysiological events in ischemia-reperfusion is multifactorial and deals with the perception of the oxidative stress responsible for the consequences of ischemia/reperfusion(I/R) stress following TT.Duration and severity of torsion also play a significant role in the oxidative stress.A detrimental result of the defense system of the testes takes place resulting finally in testicular atrophy and impaired function.Antioxidant factors have been experimentally studied in an effort to front this state.They have been classified as endogenous or exogenous antioxidants.Endogenous antioxidants comprise a structure of enzymic enzymatic and nonenzymic enzymatic particles presented within cytoplasm and numerous other subunits in the cells.Exogenous antioxidants include a variety of natural and pharmaceutical agents that may prevent or ameliorate the harmful effects of I/R injury.In this study we review those factors and their ability to enhance the oxidative status of the testis.A feature insight into where we are heading is attempted.

Warm HTK donor pretreatment reduces liver injury during static cold storage in experimental rat liver transplantation

BACKGROUND： Organ shortage has led to an increased number of transplantations from extended criteria donors. These organs are more vulnerable to ischemia-reperfusion injury. Thus, improvement of organ preservation is needed. HTK is a widely used preservation solution for static cold storage in liver transplantation. The present study was to investigate the beneficial effect of warm HTK donor pretreatment on liver preservation.

Experimental repetitive mild traumatic brain injury induces deficits in trabecular bone microarchitecture and strength in mice

To evaluate the long-term consequence of repetitive mild traumatic brain injury （mTBI） on bone, mTBI was induced in 10-week-old female C57BL/6J mice using a weight drop model, once per day for 4 consecutive days at different drop heights （0.5, 1 and 1.5 m） and the skeletal phenotype was evaluated at different time points after the impact. In vivo micro-CT （μ-CT） analysis of the tibial metaphysis at 2, 8 and 12 weeks after the impact revealed a 5%-32% reduction in trabecular bone mass. Histomorphometric analyses showed a reduced bone formation rate in the secondary spongiosa ofl.5 m impacted mice at 12 weeks post impact. Apparent modulus （bone strength）, was reduced by 30% （P 〈 0.05） at the proximal tibial metaphysis in the 1.5 m drop height group at 2 and 8 weeks post impact. Ex vivo μ-CT analysis of the fifth lumbar vertebra revealed a significant reduction in trabecular bone mass at 12 weeks of age in all three drop height groups. Serum levels of osteocalcin were decreased by 22%, 15%, and 19% in the 0.5, 1.0 and 1.5 m drop height groups, respectively, at 2 weeks post impact. Serum IGF-I levels were reduced by 18%-32% in mTBI mice compared to control mice at 2 weeks post impact. Serum osteocalcin and IGF-I levels correlated with trabecular BV/TV （r2 = 0.14 and 0.16, P 〈 0.05）. In conclusion, repetitive mTBI exerts significant negative effects on the trabecular bone microarchitecture and bone mechanical properties by influencing osteoblast function via reduced endocrine IGF-I actions.

An Experimental Study of Craniocerebral Injury Caused by 7. 62 mm Bullets in Dogs

The experimental models of craniocercbral wounds caused by 7. 62 mm bullets, i. e. thepenetrating craniocerebral injury, the tangential brain injury and the tangential skull injury, were es-tablished in dogs. The craniocerebral ballistics, craniocerebral pathology, serum and cerebrospinal flu-id total lactate dehydrogenase, blood-brain barrier permcabalities, and the pathophysiology ofcardiovascular and respiratory systems were studied. These results suggest that: 1. These injuries ofhigh-velocity missile can all cause general brain damage and intracranio-hematomas ; 2. The severityof the wound depends on the site of the injury, the kinetic energy of the missile force and the effectof the temporary cavity ; 3. The brain injury can seriously damage the blood brain barrier, leadingto brain edema ; 4. The dysfunction of respiratory and cardiovascular system is the fatal complicationendangering the life of the subjects ; 5. Estimating serum and cerebrospinal fluid total lactatedehydrogenase is a simple and valuable way to judge the severity and prognosis of this injury.

An Experimental Study on the Treatment with High Dose Dexamethasone of Craniocerebral Injury Caused by 7.62mm Bullets in Dogs

The effect of high dose dexamethasone(5 mg/kg wt,intravenous injection)to preventand treat secondary pathological damage due to craniocerebral injury was studied in an animal modelof craniocerebral injury caused by high-velocity missiles in dogs.We observed the physiologicalchanges,analyzed the level of serum and cerebrospinal fluid lactate dehydrogenase,cstimated thepermeability of blood brain barrier(BBB)and studied brain pathology by light and electronmicroscopy.The rusults suggest that high dose dexarnethasone can help to restore the structure andfunction of BBB,protect the brain cells,lessen the secondary pathological damage in the respiratoryand circulatory systams,and reduce the production of lipoperoxides(LPO).

Effect of Intra-arachnoid Space Perfusion on Thromboxane A and Prostacycline in Experimental Spinal Cord Injury

In order to understand the relation between TXA2- PGI2 and secondary trauma and the effect of intra-arachnoid perfusion of dexamethasone and verapamil on alteration of TXA,-PGI, following spinal cord injury, TXB2 and 6-keto-PGFconcentration and pathological changes in injured site 1, 2, 4 and 6 h after injury were studied using a rabbit spinal cord injury model by Allen's weight drop method.

Comparison of the effects of intravitreal bevacizumab and dexamethasone in experimental posterior penetrating eye injury

AIM： To compare the effects of intravitreal anti-vascular endothelial growth factor（VEGF） and dexamethasone in an experimental rabbit model of posterior penetrating ocular injury.METHODS： Thirty white New Zealand rabbits were included in the study. A posterior penetrating ocular injury was performed at the superotemporal quadrant. They were randomly divided into three groups. The rabbits in group 1 received intravitreal dexamethasone, in group 2 they received intravitreal bevacizumab and those in group 3 received intravitreal physiological saline solution in both eyes. All eyes were examined ophthalmologically on the 1^st, 3^rd, 7^th, 14^th and 28^th days following the injury and the clinical findings were scored. On the day 28, the eyes were enucleated, evaluated and scored macroscopically, histopathologically and scanning electron microscopically.RESULTS： The median clinical score on the 14 th and 28 th days and the median macroscopic score of the dexamethasone group was significantly better than that of control（P=0.004, 0.018）. Dexamethasone group was also better than that of bevacizumab group but the differences did not reach statistical significance. Retinal detachment rate was 8.3%, 16.6% and 12.5% in the dexamethasone group, bevacizumab group and control group, respectively（P=0.476）. More extensive fibrocelluler proliferations were observed in controls compared with dexamethasone and bevacizumab groups. But these differences did not reach the statistical significance（P=0.538）. In scanning electron microscopy all groups showed fibreous stalk and dense collagen fibrils in vitreous. CONCLUSION： This study shows that intravitreal injection of both dexamethasone and bevacizumab may reduce the intraocular fibrous proliferation after an experimental posterior penetrating ocular injury in rabbits.

Experimental nerve transfer model in the neonatal rat

Clinically,peripheral nerve reconstructions in neonates are most frequently applied in brachial plexus birth injuries.Most surgical concepts,however,have investigated nerve reconstructions in adult animal models.The immature neuromuscular system reacts differently to the effects of nerve lesion and surgery and is poorly investigated due to the lack of reliable experimental models.Here,we describe an experimental forelimb model in the neonatal rat,to study these effects on both the peripheral and central nervous systems.Within 24 hours after birth,three groups were prepared:In the nerve transfer group,a lesion of the musculocutaneous nerve was reconstructed by selectively transferring the ulnar nerve.In the negative control group,the musculocutaneous nerve was divided and not reconstructed and in the positive control group,a sham surgery was performed.The animal's ability to adapt to nerve lesions and progressive improvement over time were depict by the Bertelli test,which observes the development of grooming.Twelve weeks postoperatively,animals were fully matured and the nerve transfer successfully reinnervated their target muscles,which was indicated by muscle force,muscle weight,and cross sectional area evaluation.On the contrary,no spontaneous regeneration was found in the negative control group.In the positive control group,reference values were established.Retrograde labeling indicated that the motoneuron pool of the ulnar nerve was reduced following nerve transfer.Due to this post-axotomy motoneuron death,a diminished amount of motoneurons reinnervated the biceps muscle in the nerve transfer group,when compared to the native motoneuron pool of the musculocutaneous nerve.These findings indicate that the immature neuromuscular system behaves profoundly different than similar lesions in adult rats and explains reduced muscle force.Ultimately,pathophysiologic adaptations are inevitable.The maturing neuromuscular system,however,utilizes neonatal capacity of regeneration and seizes a variety of compensation mechanism to restore a functional extremity.The above described neonatal rat model demonstrates a constant anatomy,suitable for nerve transfers and allows all standard neuromuscular analyses.Hence,detailed investigations on the pathophysiological changes and subsequent effects of trauma on the various levels within the neuromuscular system as well as neural reorganization of the neonatal rat may be elucidated.This study was approved by the Ethics Committee of the Medical University of Vienna and the Austrian Ministry for Research and Science(BMWF-66.009/0187-WF/V/3 b/2015)on March 20,2015.

Alteration of Nitric Oxide Synthase in Experimental Spinal Cord Injury in Rats

In order to detect the role of NO to the secondary damage following spinal cord injury (SCI). NOS in the injury site (T\-8) were studied using a rat SCI model induced by Allens weight drop method (10 g2.5 cm). The results suggested that activities of NOS significantly increased in 10 min\, 1\,2\,4\,8 h. The results indicated that NO was related to SCI. The rise of NO following SCI might lead to secondary spinal cord damage.\;

Experimental studies on the treatment and pathological basis of combined radiation and burn injury

OBJECTIVE: To investigate therapeutics for and the pathological basis of combined radiation and burn injuries. METHODS: Combined radiation and burn injuries on mice and rats were inflicted by gamma ray irradiation from a (60)Co source and thermal radiation from a 5 kW bromotungsten lamp. RESULTS: The dysfunction of myocardium played an important role in the development of early stage shock. Transfusion of irradiated (in vitro, 20 Gy) or stored (4 degrees C, 7 days) blood after irradiation was done to promote the success of allo-transplantation of bone marrow. Decrease of IL-4 mRNA expression was the molecular basis of depression of intestinal mucosa immune and intervention of IL-4 showed an antagonistic effect on enterogenic infection. A new lipid component extracted from burn eschar was documented for the first time and its toxic effects were elucidated. The survival rate of alloskin grafts after removal of burn eschar from the recipient animals was obviously increased in combined injury due to reduction of immune rejection activity by the radiation effect. In contrast, in animal models with simple burn, the alloskin grafts were all rejected within ten days after the procedure. A successful therapeutic result (survival rate: 92% for 30 days and 67% for 100 days) was obtained by comprehensive management of treated animals, while the untreated control animals all died within 3 - 7 days after injury. CONCLUSION: The pathogenesis of injury caused by simultaneous radiation and burn is extremely complicated and the treatment is very difficult. A comprehensive management program consisting of several therapeutic measures aimed at key links of the pathogenesis may achieve significantly improved results.

Experimental study on terahertz radiation

In this letter, we describe a coherent subpicosecond terahertz (THz) spectroscopy system based on non-resonant optical rectification for the generation of THz radiation. We studied the two-photon absorption (TPA) of ZnTe induced by femtosecond laser pulses via THz generation, and its influence on the generation of THz radiation. Experimental results demonstrated that the intensity of pump beam against TPA must be traded off to get an optimum generation of THz radiation. As an example, we measured absorption spectrum of water vapor by time-domain spectroscopy (TDS) in the frequency range from 0.5 to 2.5 THz with a high overall accuracy.

Experimental measurement of radiation dose in a dedicated breast CT system

Radiation dose is an important performance indicator of a dedicated breast CT（DBCT）.In this paper,the method of putting thermoluminescent dosimeters（TLD） into a breast shaped PMMA phantom to study the dose distribution in breasts was improved by using smaller TLDs and a new half-ellipsoid PMMA phantom.Then the weighted CT dose index（CTDI_w） was introduced to average glandular assessment in DBCT for the first time and two measurement modes were proposed for different sizes of breasts.The dose deviations caused by using cylindrical phantoms were simulated using the Monte Carlo method and a set of correction factors were calculated.The results of the confirmatory measurement with a cylindrical phantom（11 cm/8 cm） show that CTDI_w gives a relatively conservative overestimate of the average glandular dose comparing to the results of Monte Carlo simulation and TLDs measurement.But with better practicability and stability,the CTDI_w is suitable for dose evaluations in daily clinical practice.Both of the TLDs and CTDI_w measurements demonstrate that the radiation dose of our DBCT system is lower than conventional two-view mammography.

EXPERIMENTAL RESEARCH ON RADIATION FROM DOUBLE CYLINDRICAL STRUCTURES

An experiment on radiation from double cylindrical structures was held in an open-air pond. Radiation responses from one-point harmonic force driven model and two-point stochastic forces driven model were measured. Numerical results show a good agreement with the experimental results. Possible errors are analyzed.

A study on mitochondrial respiratory dysfunction and lipid peroxidation in the liver after radiation,burn,and combined radiation-burn injuries in mice

Male mice were subjected to 6 Gy total body irradiation,20% TBSAfull-thickness burns,or combined radiation-burn injury and lipid peroxides(LPO),vita-min E,sulfhydryl group,respiratory control ratio(RCR),ADP/O ratio,and cytochromeoxidase activity of the liver mitochondria were determined in the first 9 d postinjury.Theresults are as follows:(1)LPO level increased in the early postinjury stage after combinedradiation-burn injury,on the 5th-7th day after irradiation and on the 7th day postburn.(2)Vitamin E level decreased significantly in the two groups of radiation and burn inju-ries but showed no significant decrease after combined injury.(3)The sulfhydryl groupshowed a tendency to increase in all the 3 groups.(4)The activity of cytochrome oxidaseincreased significantly on the 7th day after radiation but decreased considerably in theburn and combined injury groups.(5)RCR and ADP/O ratio decreased more significantlyin the combined injury group than in either the radiation group or the burn group.These facts suggest that the respiratory dysfunction of the liver mitochondria results mostprobably from the damage on the mitochondrial membrane due to lipid peroxidation.

Clinical and Experimental Study on Prevention and Treatment of Acute Radiation Injury in Nasopharyngeal Carcinoma Patients by Yiqi Huoxue Yangyin Recipe (益气活血养阴方)

Objective: To observe the effect of Chinese herbal medicine in alleviating acute toxic adverse effect of radiotherapy and on growth of stromal cells in bone marrow. Methods: Seventy two patients with nasopharyngeal carcinoma (NPC) were randomly divided into two groups. Radical radiotherapy was applied to both groups. In the radiotherapeutic period, to the 36 patients in the treated group, Yiqi Huoxue Yangyin Recipe (YHYR) was given additionally by oral taking and compressing on radiation area, and to the 36 patients in the control group, vitamin B 12 solution was given for gargling or compressing. Experimental study was carried out in rats of two groups, irradiated with 5.0 Gy X ray and treated with YHYR or normal saline intraperitoneally, to observe the colony forming unit fibroblastoid (CFU F) in cultured bone marrow stromal cells (BMSC), taken from the rats at different time.Results: The oral mucomembranous radiation damage occurred in 47.2% of the treated group when the dose of radiation reached to 41.4±9.4 Gy, while in the control group, it was 91.7% when the dose reached to 30.9±8.9 Gy. The skin radiation damage occurrence rate in the two groups was 13.9% and 33.3% respectively when the dose of radiation reached to 50.2±5.6 Gy and 43.2±6.3 Gy respectively. Comparison of the two groups showed significant difference ( P <0.01), the radiation damage was significantly slighter in the treated group. Experimental study showed that the rats in the two groups were significantly different in occurrence and degree of bone marrow function inhibition, P <0.01. The numbers of CFU F in cultured BMSC of radiation damaged rats taken at respective different culture time were also significantly different between the two groups, P < 0.01 .Conclusion: YHYR could significantly reduce acute radiation damage of mucomembrane and skin, alleviate the inhibition on bone marrow function, and eliminate the injury of radiation on BMSC.

Role of Active Principles of Podophyllum hexandrum in Amelioration of Radiation Mediated Lung Injuries by Reactive Oxygen/Nitrogen Species Reduction

Radiation induced reactive oxygen/nitrogen species (ROS/RNS) are reported to cause lung injuries such as pneumonitis and fibrosis which may be fatal at times. Current study is designed to analyse the radioprotective efficacy of P. hexandrum active principles (G-002M) on lungs of mice exposed to high dose of gamma irradiation (7 Gy). Cellular profiles and inflammatory cell infiltrates of irradiated bronchoalveolar lavage fluid (BALF) have shown correlations with lung pathology. Cell counts were determined in BALF of control, 7 Gy radiation exposed and radiation with G-002M pretreated mice. ROS/Nitric Oxide (NO) production was measured by 2,7?dichlorodihydrofluorescein diacetate (DCF-DA) and diaminofluorescein diacetate (DAF-2DA) through microscopy and flow cytometry respectively. Immunostaining of inducible nitric oxide synthase (iNOS) in BALF cells and lung sections was also observed microscopically. iNOS ex- pression was observed in lungs by western blotting. BALF was also processed to estimate total protein, LDH, and phospholipids content. Catalase, reduced Glutathione (GSH), Glutathione reductase (GR) and lipid peroxidation were estimated in lung tissues. Pre-administration of G-002M significantly decreased radiation mediated neutrophils count in BALF of irradiated mice. ROS generation, iNOS expression, total protein, LDH and phospholipids were found less affected in G-002M pretreated group in comparison to radiation alone group. Radiation exposure to mice was found apparently leading to parenchymal fibrosis, an architectural distortion of the lung tissue with edema, infiltration of inflammatory blood cells with increased immunolabeling of iNOS. G-002M pretreatment significantly countered radiation mediated increased lipid peroxidation and decreased GR, catalase and GSH in mice. Current study demonstrates possible role of P. hexandrum (G-002M) in minimizing lung damage induced by radiation mediated ROS/RNS generation.