Selective brain hypothermia-induced neuroprotection against focal cerebral ischemia/reperfusion injury is associated with Fis1 inhibition

Selective brain hypothermia is considered an effective treatment for neuronal injury after stroke,and avoids the complications of general hypothermia.However,the mechanisms by which selective brain hypothermia affects mitochondrial fission remain unknown.In this study,we investigated the effect of selective brain hypothermia on the expression of fission 1 (Fis1) protein,a key factor in the mitochondrial fission system,during focal cerebral ischemia/reperfusion injury.Sprague-Dawley rats were divided into four groups.In the sham group,the carotid arteries were exposed only.In the other three groups,middle cerebral artery occlusion was performed using the intraluminal filament technique.After 2 hours of occlusion,the filament was slowly removed to allow blood reperfusion in the ischemia/reperfusion group.Saline,at 4℃ and 37℃,were perfused through the carotid artery in the hypothermia and normothermia groups,respectively,followed by restoration of blood flow.Neurological function was assessed with the Zea Longa 5-point scoring method.Cerebral infarct volume was assessed by 2,3,5-triphenyltetrazolium chloride staining,and apoptosis was assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining.Fis1 and cytosolic cytochrome c levels were assessed by western blot assay.Fis1 mRNA expression was assessed by quantitative reverse transcription-polymerase chain reaction.Mitochondrial ultrastructure was evaluated by transmission electron microscopy.Compared with the sham group,apoptosis,Fis1 protein and mRNA expression and cytosolic cytochrome c levels in the cortical ischemic penumbra and cerebral infarct volume were increased after reperfusion in the other three groups.These changes caused by cerebral ischemia/reperfusion were inhibited in the hypothermia group compared with the normothermia group.These findings show that selective brain hypothermia inhibits Fis1 expression and reduces apoptosis,thereby ameliorating focal cerebral ischemia/reperfusion injury in rats.Experiments were authorized by the Ethics Committee of Qingdao Municipal Hospital of China (approval No.2019008).

A safety evaluation of profound hypothermia-induced suspended animation for delayed resuscitation at 90 or 120min

Background: The successful treatment of military combat casualties with penetrating injuries is significantly dependent on the time needed to get the patient to an adequate treatment facility. Profound hypothermia induced suspended animation for delayed resuscitation(SADR) is a novel approach for inducing cardiac arrest and buying additional time for such injuries. However, the time used to safely administer circulatory arrest(CA) is controversial. The goal of this study was to evaluate the safety of hypothermia-induced SADR over 90 and 120 min time intervals.Methods: Sixteen male BAMA minipigs were randomized into two groups: CA90 group(90 min, n =8) and CA120 group(120 min, n =8). Cannulation of the right common carotid arteries and internal jugular veins was performed to establish cardiopulmonary bypass for each animal. Through the perfusion of cold organ preservation solution(OPS), cardioplegia and profound hypothermia(15℃) were induced. After CA, cardiopumonary bypass(CPB) was restarted, and the animals were gradually re-warmed and resuscitated. The animals were assisted with ventilators until spontaneous breathing was achieved. The index of hemodynamic perioperative serum chemistry values [alanine transaminase(ALT), aspartate aminotransferase(AST), creatinine(CR), lactic dehydrogenase(LDH) and troponin T(TnT)] and survival were observed from pre-operation to 7 days post-operation.Results: Fifteen animals were enrolled in the experiment, while 1 animal in CA120 group died from surgical error. All 8 animals in CA90 group recovered, with only 1 animal displaying mild disability. However, in CA120 group, only 2 animals survived with severe disability, and the other 5 animals died after 2 days post-operation. In CA90 group, the perioperative serum chemistry values increased at 1 day post-operation(ALT 84.43±18.65 U/L; AST 88.99±23.19 U/L; Cr 87.90±24.49μmol/L; LDH 1894.13±322.26 U/L; TnT 0.849±0.135 ng/ml) but decreased to normal or almost normal levels at 7 days post-operation(ALT 52.48±9.04 U/L; AST 75.23±21.46 U/L; Cr 82.69±18.41μmol/L; LDH 944.67±834.32 U/L; TnT 0.336±0.076 ng/ml).Conclusion: Profound hypothermia-induced SADR is an effective method for inducing cardiac arrest. Our results indicate that inducing CA for 90 min(at 15℃) is safer than doing so for 120 min. Our results indicate that 120 min of CA at 15℃ is dangerous and can result in high mortality and severe neurological complications. Further experimentation is needed to determine whether 120 min of CA at temperatures lower than 15℃ can lead to safe recovery.

Electrocardiographic changes during induced therapeutic hypothermia in comatose survivors after cardiac arrest

AIM: To assess the safety of therapeutic hypothermia(TH) concerning arrhythmias we analyzed serial electrocardiograms(ECG) during TH.METHODS: All patients recovered from a cardiac arrest with Glasgow < 9 at admission were treated with induced mild TH to 32-34℃. TH was obtained with cool fluid infusion or a specific intravascular device. Twelvelead ECG before,during,and after TH,as well as ECG telemetry data was recorded in all patients. From a total of 54 patients admitted with cardiac arrest during the study period,47 patients had the 3 ECG and telemetry data available. ECG analysis was blinded and performed with manual caliper by two independent cardiologists from blinded copies of original ECG,recorded at 25 mm/s and 10 mm/m V. Coronary care unit staff analyzed ECG telemetry for rhythm disturbances. Variables measured in ECG were rhythm,RR,PR,QT and corrected QT(QTc by Bazett formula,measured in lead v2) intervals,QRS duration,presence of Osborn's J wave and U wave,as well as ST segment displacement and T wave amplitude in leads Ⅱ,v2 and v5.RESULTS: Heart rate went down an average of 19 bpm during hypothermia and increased again 16 bpm with rewarming(P < 0.0005,both). There was a nonsignificant prolongation of the PR interval during TH and a significant decrease with rewarming(P = 0.041). QRS duration significantly prolonged(P = 0.041) with TH and shortened back(P < 0.005) with rewarming. QTc interval presented a mean prolongation of 58 ms(P < 0.005) during TH and a significant shortening with rewarming of 22.2 ms(P = 0.017). Osborn or J wave was found in 21.3% of the patients. New arrhythmias occurred in 38.3% of the patients. Most frequent arrhythmia was non-sustained ventricular tachycardia(19.1%),followed by severe bradycardia or paced rhythm(10.6%),accelerated nodal rhythm(8.5%) and atrial fibrillation(6.4%). No life threatening arrhythmias(sustained ventricular tachycardia,polymorphic ventricular tachycardia or ventricular fibrillation) occurred during TH. CONCLUSION: A 38.3% of patients had cardiac arrhythmias during TH but without life-threatening arrhythmias. A concern may rise when inducing TH to patients with long QT syndrome.

Ondansetron and Hypothermia Induced Cardiac Arrest in a 97-Year-Old Woman: A Case Report

Background:Ondansetron and hypothermia are both known to induce bradycardia or QT interval prolongation,thus placing affected patients at risk of cardiac arrest.Case Report:Herein,we report the case of a 97-year-old woman who initially presented with confusion and hypothermia,and experienced severe bradycardia and asystolic cardiac arrest after a 4 mg intravenous ondansetron bolus injection.Conclusion:Ondansetron is associated with bradycardia and QTc prolongation,both of which might be further exacerbated by hypothermia.Clinicians should be aware that administering ondansetron in patients with hypothermia might further increase the risk of adverse cardiac events and eventual cardiac arrest.

Moderate hypothermia attenuates lung in flammation inlipopolysaccharide- induced acute lung injury in rats

Objective To investigate the role of moderate h.vpothennia in the lung inflammation of rat acute lung injury induced by lipopolysaccharide(LPS). Methods A rat model of acute lung injury (ALl) was established by in-tin-tracheal instillation of lipopolysaccharide ( 1.5 mg/kg, 0.5 ml) at 16 h after LPS ( 1.0 mg/kg) intraperitoneal adrninis-tmtion. Thirty-four male Sprague Dawley rats were randomly divided into four groups: control group, receiving saline only;LPS group, receiving LPS; hypothennia group, treated with hypothennia without LPS; LPS + hypothennia group, treated with LPS and cooled to 32.5℃-33.0℃ as PaO2/FiO2. was below 300 mmHg. Hemodynamics and blood gases were record-ed every hour throughout the study. Rats were killed 4 h after ALl, and lung lavage was performed to measure the tumor ne-crosis factor α(TNF-α), interleukin-6 (IL-6) and interleukin-10 (IL-10) concentrations in bronchoalveolar lavage fluid (BALF) by using enzyme-linked immunosorbent assay (ELISA). Results PaO2/FiO2 was significantly decreased and PaCO2 was increased in the LPS group as compared to their baseline values( P＜0.01). Treatment with hypothermia inhib-ited the increase in PaCO2( P＜0.05) but had no effect on PaO2/FiO2 in the presence of LPS. The administration of LPS significantly increased the concentrations of TNF-α, IL-6 and IL-10 in BALF as compared to the control experiment( P＜0.05, P＜0.01 ). Moderate hypothermia reduced the expressions of TNF-α and IL-6 ( P＜0.01 ) but had no effect on the production of IL-10 ( P＞0.05). Conclusion Moderate hypothermia significantly inhibits proinflammatory cytokine ex-pressions in lipopolysaccharide-induced acute lung injury.

Induced pluripotent stem cell-related approaches to generate dopaminergic neurons for Parkinson's disease

The progressive loss of dopaminergic neurons in affected patient brains is one of the pathological features of Parkinson's disease,the second most common human neurodegenerative disease.Although the detailed pathogenesis accounting for dopaminergic neuron degeneration in Parkinson's disease is still unclear,the advancement of stem cell approaches has shown promise for Parkinson's disease research and therapy.The induced pluripotent stem cells have been commonly used to generate dopaminergic neurons,which has provided valuable insights to improve our understanding of Parkinson's disease pathogenesis and contributed to anti-Parkinson's disease therapies.The current review discusses the practical approaches and potential applications of induced pluripotent stem cell techniques for generating and differentiating dopaminergic neurons from induced pluripotent stem cells.The benefits of induced pluripotent stem cell-based research are highlighted.Various dopaminergic neuron differentiation protocols from induced pluripotent stem cells are compared.The emerging three-dimension-based brain organoid models compared with conventional two-dimensional cell culture are evaluated.Finally,limitations,challenges,and future directions of induced pluripotent stem cell–based approaches are analyzed and proposed,which will be significant to the future application of induced pluripotent stem cell-related techniques for Parkinson's disease.

Induced neural stem cells regulate microglial activation through Akt-mediated upregulation of CXCR4 and Crry in a mouse model of closed head injury

Microglial activation that occurs rapidly after closed head injury may play important and complex roles in neuroinflammation-associated neuronal damage and repair.We previously reported that induced neural stem cells can modulate the behavior of activated microglia via CXCL12/CXCR4 signaling,influencing their activation such that they can promote neurological recovery.However,the mechanism of CXCR4 upregulation in induced neural stem cells remains unclear.In this study,we found that nuclear factor-κB activation induced by closed head injury mouse serum in microglia promoted CXCL12 and tumor necrosis factor-αexpression but suppressed insulin-like growth factor-1 expression.However,recombinant complement receptor 2-conjugated Crry(CR2-Crry)reduced the effects of closed head injury mouse serum-induced nuclear factor-κB activation in microglia and the levels of activated microglia,CXCL12,and tumor necrosis factor-α.Additionally,we observed that,in response to stimulation(including stimulation by CXCL12 secreted by activated microglia),CXCR4 and Crry levels can be upregulated in induced neural stem cells via the interplay among CXCL12/CXCR4,Crry,and Akt signaling to modulate microglial activation.In agreement with these in vitro experimental results,we found that Akt activation enhanced the immunoregulatory effects of induced neural stem cell grafts on microglial activation,leading to the promotion of neurological recovery via insulin-like growth factor-1 secretion and the neuroprotective effects of induced neural stem cell grafts through CXCR4 and Crry upregulation in the injured cortices of closed head injury mice.Notably,these beneficial effects of Akt activation in induced neural stem cells were positively correlated with the therapeutic effects of induced neural stem cells on neuronal injury,cerebral edema,and neurological disorders post–closed head injury.In conclusion,our findings reveal that Akt activation may enhance the immunoregulatory effects of induced neural stem cells on microglial activation via upregulation of CXCR4 and Crry,thereby promoting induced neural stem cell–mediated improvement of neuronal injury,cerebral edema,and neurological disorders following closed head injury.

Human induced pluripotent stem cell-derived therapies for regeneration after central nervous system injury

In recent years,the progression of stem cell therapies has shown great promise in advancing the nascent field of regenerative medicine.Considering the non-regenerative nature of the mature central nervous system,the concept that“blank”cells could be reprogrammed and functionally integrated into host neural networks remained intriguing.Previous work has also demonstrated the ability of such cells to stimulate intrinsic growth programs in post-mitotic cells,such as neurons.While embryonic stem cells demonstrated great potential in treating central nervous system pathologies,ethical and technical concerns remained.These barriers,along with the clear necessity for this type of treatment,ultimately prompted the advent of induced pluripotent stem cells.The advantage of pluripotent cells in central nervous system regeneration is multifaceted,permitting differentiation into neural stem cells,neural progenitor cells,glia,and various neuronal subpopulations.The precise spatiotemporal application of extrinsic growth factors in vitro,in addition to microenvironmental signaling in vivo,influences the efficiency of this directed differentiation.While the pluri-or multipotency of these cells is appealing,it also poses the risk of unregulated differentiation and teratoma formation.Cells of the neuroectodermal lineage,such as neuronal subpopulations and glia,have been explored with varying degrees of success.Although the risk of cancer or teratoma formation is greatly reduced,each subpopulation varies in effectiveness and is influenced by a myriad of factors,such as the timing of the transplant,pathology type,and the ratio of accompanying progenitor cells.Furthermore,successful transplantation requires innovative approaches to develop delivery vectors that can mitigate cell death and support integration.Lastly,host immune responses to allogeneic grafts must be thoroughly characterized and further developed to reduce the need for immunosuppression.Translation to a clinical setting will involve careful consideration when assessing both physiologic and functional outcomes.This review will highlight both successes and challenges faced when using human induced pluripotent stem cell-derived cell transplantation therapies to promote endogenous regeneration.

Insights into skullcap herb-induced liver injury

This editorial addresses the growing concern of herb-induced liver injury(HILI),focusing on a unique case of Skullcap-induced HILI report.This editorial underscore the significant mortality rate linked to Skullcap-induced HILI,emphasizing the importance of vigilant monitoring and intervention.As herbal supplement usage rises,collaboration among clinicians and researchers is crucial to comprehend and address the complexities of HILI,particularly those involving Skullcap.

Transplantation of fibrin-thrombin encapsulated human induced neural stem cells promotes functional recovery of spinal cord injury rats through modulation of the microenvironment

Recent studies have mostly focused on engraftment of cells at the lesioned spinal cord,with the expectation that differentiated neurons facilitate recovery.Only a few studies have attempted to use transplanted cells and/or biomaterials as major modulators of the spinal cord injury microenvironment.Here,we aimed to investigate the role of microenvironment modulation by cell graft on functional recovery after spinal cord injury.Induced neural stem cells reprogrammed from human peripheral blood mononuclear cells,and/or thrombin plus fibrinogen,were transplanted into the lesion site of an immunosuppressed rat spinal cord injury model.Basso,Beattie and Bresnahan score,electrophysiological function,and immunofluorescence/histological analyses showed that transplantation facilitates motor and electrophysiological function,reduces lesion volume,and promotes axonal neurofilament expression at the lesion core.Examination of the graft and niche components revealed that although the graft only survived for a relatively short period(up to 15 days),it still had a crucial impact on the microenvironment.Altogether,induced neural stem cells and human fibrin reduced the number of infiltrated immune cells,biased microglia towards a regenerative M2 phenotype,and changed the cytokine expression profile at the lesion site.Graft-induced changes of the microenvironment during the acute and subacute stages might have disrupted the inflammatory cascade chain reactions,which may have exerted a long-term impact on the functional recovery of spinal cord injury rats.

Long non-coding RNA H19 regulates neurogenesis of induced neural stem cells in a mouse model of closed head injury

Stem cell-based therapies have been proposed as a potential treatment for neural regeneration following closed head injury.We previously reported that induced neural stem cells exert beneficial effects on neural regeneration via cell replacement.However,the neural regeneration efficiency of induced neural stem cells remains limited.In this study,we explored differentially expressed genes and long non-coding RNAs to clarify the mechanism underlying the neurogenesis of induced neural stem cells.We found that H19 was the most downregulated neurogenesis-associated lnc RNA in induced neural stem cells compared with induced pluripotent stem cells.Additionally,we demonstrated that H19 levels in induced neural stem cells were markedly lower than those in induced pluripotent stem cells and were substantially higher than those in induced neural stem cell-derived neurons.We predicted the target genes of H19 and discovered that H19 directly interacts with mi R-325-3p,which directly interacts with Ctbp2 in induced pluripotent stem cells and induced neural stem cells.Silencing H19 or Ctbp2 impaired induced neural stem cell proliferation,and mi R-325-3p suppression restored the effect of H19 inhibition but not the effect of Ctbp2 inhibition.Furthermore,H19 silencing substantially promoted the neural differentiation of induced neural stem cells and did not induce apoptosis of induced neural stem cells.Notably,silencing H19 in induced neural stem cell grafts markedly accelerated the neurological recovery of closed head injury mice.Our results reveal that H19 regulates the neurogenesis of induced neural stem cells.H19 inhibition may promote the neural differentiation of induced neural stem cells,which is closely associated with neurological recovery following closed head injury.

Recent advances in the diagnosis of drug-induced liver injury

Drug-induced liver injury(DILI)is a major problem in the United States,commonly leading to hospital admission.Diagnosing DILI is difficult as it is a diagnosis of exclusion requiring a temporal relationship between drug exposure and liver injury and a thorough work up for other causes.In addition,DILI has a very variable clinical and histologic presentation that can mimic many different etiologies of liver disease.Objective scoring systems can assess the probability that a drug caused the liver injury but liver biopsy findings are not part of the criteria used in these systems.This review will address some of the recent updates to the scoring systems and the role of liver biopsy in the diagnosis of DILI.

Coupled multiphysical model for investigation of influence factors in the application of microbially induced calcite precipitation

The study presents a comprehensive coupled thermo-bio-chemo-hydraulic(T-BCH)modeling framework for stabilizing soils using microbially induced calcite precipitation(MICP).The numerical model considers relevant multiphysics involved in MICP,such as bacterial ureolytic activities,biochemical reactions,multiphase and multicomponent transport,and alteration of the porosity and permeability.The model incorporates multiphysical coupling effects through well-established constitutive relations that connect parameters and variables from different physical fields.It was implemented in the open-source finite element code OpenGeoSys(OGS),and a semi-staggered solution strategy was designed to solve the couplings,allowing for flexible model settings.Therefore,the developed model can be easily adapted to simulate MICP applications in different scenarios.The numerical model was employed to analyze the effect of various factors,including temperature,injection strategies,and application scales.Besides,a TBCH modeling study was conducted on the laboratory-scale domain to analyze the effects of temperature on urease activity and precipitated calcium carbonate.To understand the scale dependency of MICP treatment,a large-scale heterogeneous domain was subjected to variable biochemical injection strategies.The simulations conducted at the field-scale guided the selection of an injection strategy to achieve the desired type and amount of precipitation.Additionally,the study emphasized the potential of numerical models as reliable tools for optimizing future developments in field-scale MICP treatment.The present study demonstrates the potential of this numerical framework for designing and optimizing the MICP applications in laboratory-,prototype-,and field-scale scenarios.

Inadvertent perioperative hypothermia and surgical site infections after liver resection

Background:In the overall surgical population,inadvertent perioperative hypothermia has been associated with an increased incidence of surgical site infection(SSI).However,recent clinical trials did not validate this notion.This study aimed to investigate the potential correlation between inadvertent perioperative hypothermia and SSIs following liver resection.Methods:This retrospective cohort study included all consecutive patients who underwent liver resection between January 2019 and December 2021 at the First Affiliated Hospital,Zhejiang University School of Medicine.Perioperative temperature managements were implemented for all patients included in the analysis.Estimated propensity score matching(PSM)was performed to reduce the baseline imbalances between the normothermia and hypothermia groups.Before and after PSM,univariate analyses were performed to evaluate the correlation between hypothermia and SSI.Multivariate regression analysis was performed to determine whether hypothermia was an independent risk factor for postoperative transfusion and major complications.Subgroup analyses were performed for diabetes mellitus,age>65 years,and major liver resection.Results:Among 4000 patients,2206 had hypothermia(55.2%),of which 150 developed SSI(6.8%).PSM yielded 1434 individuals in each group.After PSM,the hypothermia and normothermia groups demonstrated similar incidence rates of SSI(7.0%vs.6.3%,P=0.453),postoperative transfusion(13.7%vs.13.3%,P=0.743),and major complications(10.1%vs.9.0%,P=0.309).Univariate regression analysis revealed no significant effects of hypothermia on the incidence of SSI in the group with the highest hypothermia exposure[odds ratio(OR)=1.25,95%confidence interval(CI):0.84-1.87,P=0.266],the group with moderate exposure(OR=1.00,95%CI:0.65-1.53,P=0.999),or the group with the lowest exposure(OR=1.11,95%CI:0.73-1.65,P=0.628).The subgroup analysis revealed similar results.Regarding liver function,patients in the hypothermia group demonstrated lowerγ-glutamyl transpeptidase(37 vs.43 U/L,P<0.001)and alkaline phosphatase(69 vs.72 U/L,P=0.016).However,patients in the hypothermia group exhibited prolonged activated partial thromboplastin time(29.2 vs.28.6 s,P<0.001).Conclusions:In our study of patients undergoing liver resection,we found no significant association between mild perioperative hypothermia and SSI.It might be due to the perioperative temperature managements,especially active warming measures,which limited the impact of perioperative hypothermia on the occurrence of SSI.

Application value of machine learning models in predicting intraoperative hypothermia in laparoscopic surgery for polytrauma patients

BACKGROUND Hypothermia during laparoscopic surgery in patients with multiple trauma is a significant concern owing to its potential complications.Machine learning models offer a promising approach to predict the occurrence of intraoperative hypothermia.AIM To investigate the value of machine learning model to predict hypothermia during laparoscopic surgery in patients with multiple trauma.METHODS This retrospective study enrolled 220 patients who were admitted with multiple injuries between June 2018 and December 2023.Of these,154 patients were allocated to a training set and the remaining 66 were allocated to a validation set in a 7:3 ratio.In the training set,53 cases experienced intraoperative hypothermia and 101 did not.Logistic regression analysis was used to construct a predictive model of intraoperative hypothermia in patients with polytrauma undergoing laparoscopic surgery.The area under the curve(AUC),sensitivity,and specificity were calculated.RESULTS Comparison of the hypothermia and non-hypothermia groups found significant differences in sex,age,baseline temperature,intraoperative temperature,duration of anesthesia,duration of surgery,intraoperative fluid infusion,crystalloid infusion,colloid infusion,and pneumoperitoneum volume(P<0.05).Differences between other characteristics were not significant(P>0.05).The results of the logistic regression analysis showed that age,baseline temperature,intraoperative temperature,duration of anesthesia,and duration of surgery were independent influencing factors for intraoperative hypothermia during laparoscopic surgery(P<0.05).Calibration curve analysis showed good consistency between the predicted occurrence of intraoperative hypothermia and the actual occurrence(P>0.05).The predictive model had AUCs of 0.850 and 0.829 for the training and validation sets,respectively.CONCLUSION Machine learning effectively predicted intraoperative hypothermia in polytrauma patients undergoing laparoscopic surgery,which improved surgical safety and patient recovery.

Prevalence of Induced Abortion among Female Students in Selected Tertiary Learning Institutions in Gaborone City, Botswana

Induced abortion signifies that pregnancy has been tempered with. Abortion is the removal of an embryo or fetus weighing less than 500 grams from its mother. It can either be spontaneous (unprompted) or induced. Abortion remains one of the leading causes of maternal deaths in developing countries with induced abortion being the key cause. In 2014 from January to August, 9 abortion related deaths occurred in Botswana. There are several reasons female students in tertiary institutions resort to seeking induced abortion which include the socio-demographics like age and socio-economic factors like financial instability. Parental fears, unintended pregnancy and pressure from the partner also force females to terminate pregnancy. Induced abortion has claimed many women’s lives especially in developing countries with very restrictive abortion laws like Botswana as women do not access safe abortion care services. The study intends to establish the determinants of induced abortion among female students in selected tertiary learning institutions in Gaborone City, Botswana. It concentrated primarily on determining the prevalence of induced abortion. This was a descriptive cross-sectional study using both quantitative and qualitative data collection techniques. Systematic random sampling technique was used to come up with 278 participants. Prior to commencement of data collection, all ethical and logistical prerequisites were satisfied. Informed consent was solicited from all the study participants and the purpose of the study was fully explained. A self-administered questionnaire was used to collect data. Microsoft Excel spread sheet was used to code, clean, and enter the data, which was then exported for analysis to the statistical package for social sciences version 24. Frequency distribution tables, percentages graphs, and pie charts were used to illustrate the descriptive information. The study revealed that prevalence of induced abortion among female students in Gaborone City is 7.9%. They even suggested that induced abortion be liberalized. Age was the only socio-demographic factor associated with induced abortion with p = 0.047 using Chi Square test χ2 = 7.609, df = 3. The study findings concluded that female students resort to induced abortion as a result of pressure from both parents and male partners especially when the pregnancy is unintended. The study recommends that the abortion law in Botswana be made liberal to ease access to safe abortion care services. It also recommends that contraceptive commodities should consistently be available in public health facilities.

Numerical simulations of earthquake rupture induced by pressure perturbation

The subsurface fluid injection can cause pressure increase within faults,leading to earthquake occurrences.However,the factors controlling earthquake rupture due to pressure perturbation remain poorly understood.To resolve this problem,we simulate the physical processes of earthquake nucleation and rupture on strike-slip faults perturbated by pressure migration based on the slip-weakening law.Multiple kinds of factors,including background stress,fluid injection rates,the area of the pressurized region,fault geometry,and fault friction coefficients,are considered in our simulations.Our simulation results reveal that the ratio of shear stress to normal stress rather than their absolute values controls the rupture behavior.With the large stress ratios,high injection rates,and large pressurized areas,earthquakes are prone to propagate as runaway ruptures.Additionally,faults with large aspect ratios of length to width are also favorable for causing runaway ruptures.In contrast,the factors of fault strike,dip angles and friction coefficients have minor influence on rupture behavior.

Advanced Machine Learning Methods for Prediction of Blast-Induced Flyrock Using Hybrid SVR Methods

Blasting in surface mines aims to fragment rock masses to a proper size.However,flyrock is an undesirable effect of blasting that can result in human injuries.In this study,support vector regression(SVR)is combined with four algorithms:gravitational search algorithm(GSA),biogeography-based optimization(BBO),ant colony optimization(ACO),and whale optimization algorithm(WOA)for predicting flyrock in two surface mines in Iran.Additionally,three other methods,including artificial neural network(ANN),kernel extreme learning machine(KELM),and general regression neural network(GRNN),are employed,and their performances are compared to those of four hybrid SVR models.After modeling,the measured and predicted flyrock values are validated with some performance indices,such as root mean squared error(RMSE).The results revealed that the SVR-WOA model has the most optimal accuracy,with an RMSE of 7.218,while the RMSEs of the KELM,GRNN,SVR-GSA,ANN,SVR-BBO,and SVR-ACO models are 10.668,10.867,15.305,15.661,16.239,and 18.228,respectively.Therefore,combining WOA and SVR can be a valuable tool for accurately predicting flyrock distance in surface mines.

Versatile techniques based on the Thermionic Vacuum Arc(TVA)and laser-induced TVA methods for Mg/Mg:X thin films deposition-A review

Magnesium and magnesium thin alloy films were deposited using a thermionic vacuum arc(TVA),which has multiple applications in the field of metallic electrodes for diodes and batteries or active corrosion protection.An improved laser-induced TVA(LTVA)method favors the crystallization processes of the deposited magnesium-based films because the interaction between laser and plasma discharge changes the thermal energy during photonic processes due to the local temperature variation.Plasma diagnosis based on current discharge measurements suggests an inelastic collision between the laser beam and the atoms from the plasma discharge.The morphology and surface properties of the obtained thin films differ between these two methods.While the amorphous character is dominant for TVA thin films,enabling a smooth surface,the LTVA method produces rough surfaces with prominent crystallinity,less hydrophobic character and lower surface energy.The smooth surfaces obtained by the TVA methods produce metallic electrodes with good electrical contact,ensuring better diodes and battery charge transport.Both methods allow uniform magnesium alloys to be obtained,but the laser used in the LTVA on the discharge plasma controls the added metal or element ratio.

Flow-Slip Stability Behavior of Calcareous Sand Treated by Microbially Induced Carbonate Precipitation Technology

Flow-slip damage commonly destabilizes coastal slopes.Finding a slope stabilization method for calcareous sands in the South China Sea is crucial.Microbially induced calcite precipitation is a promising,eco-friendly method for soil stabilization.This study investigates the effect of microbial treatments,initial relative density,initial cell pressure,and initial stress ratio on the flow-slip stability of calcareous sand specimens by using constant shear drained tests.These tests lay the foundation to study the mechanical instability of sand slopes.Results show that the microbial-treated specimens maintain stable stresses longer,take longer to reach the instability,and withstand larger volumetric strains.Microbial treatment effectively enhances sand stability under constant shear drainage,with improvements amplified by higher initial relative density and initial cell pressure.In addition,a smaller initial stress ratio reduces shear effects on the specimen and increases resistance to flow slides.Microanalysis reveals that the flow-slip stability of calcareous sand slopes is enhanced by contact cementation,particle coating,void filling,and mutual embedment of calcium carbonate crystals.