Spectrum of delayed post-hypoxic leukoencephalopathy syndrome:A systematic review

BACKGROUND Delayed post hypoxic leukoencephalopathy syndrome(DPHLS),also known as Grinker’s myelinopathy,is a rare but significant neurological condition that manifests days to weeks after a hypoxic event.Characterized by delayed onset of neurological and cognitive deficits,DPHLS presents substantial diagnostic and therapeutic challenges.AIM To consolidate current knowledge on pathophysiology,clinical features,diagnostic approaches,and management strategies for DPHLS,providing a comprehensive overview and highlighting gaps for future research.METHODS Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyzes guidelines,we systematically searched PubMed,ScienceDirect and Hinari databases using terms related to delayed post-hypoxic leukoencephalopathy.Inclusion criteria were original research articles,case reports,and case series involving human subjects with detailed clinical,neuroimaging,or pathological data on DPHLS.Data were extracted on study characteristics,participant demographics,clinical features,neuroimaging findings,pathological findings,treatment,and outcomes.The quality assessment was performed using the Joanna Briggs Institute critical appraisal checklist.RESULTS A total of 73 cases were reviewed.Common comorbidities included schizoaffective disorder,bipolar disorder,hypertension,and substance use disorder.The primary causes of hypoxia were benzodiazepine overdose,opioid overdose,polysubstance overdose,and carbon monoxide(CO)poisoning.Symptoms frequently include decreased level of consciousness,psychomotor agitation,cognitive decline,parkinsonism,and encephalopathy.Neuroimaging commonly revealed diffuse T2 hyperintensities in cerebral white matter,sometimes involving the basal ganglia and the globus pallidus.Magnetic resonance spectroscopy often showed decreased N-acetylaspartate,elevated choline,choline-to-creatinine ratio,and normal or elevated lactate.Treatment is often supportive,including amantadine,an antioxidant cocktail,and steroids.Hyperbaric oxygen therapy may be beneficial in those with CO poisoning.Parkinsonism was often treated with levodopa.Most of the patients had substantial recovery over the course of months and many cases had some residual neurocognitive deficits.CONCLUSION DPHLS remains a complex and multifaceted condition with various etiologies and clinical manifestations.Early recognition and appropriate management are crucial to improving patient outcomes.Future research should focus on standardizing diagnostic criteria,using advanced imaging techniques,and exploring therapeutic interventions to improve understanding and treatment of DPHLS.Conducting prospective cohort studies and developing biomarkers for early diagnosis and monitoring will be essential to advance patient care.

Surgical techniques to prevent delayed gastric emptying after pancreaticoduodenectomy

Background: Delayed gastric emptying(DGE) is one of the most common complications after pancreaticoduodenectomy(PD). DGE represents impaired gastric motility without significant mechanical obstruction and is associated with an increased length of hospital stay, increased healthcare costs, and a high readmission rate. We reviewed published studies on various technical modifications to reduce the incidence of DGE. Data sources: Studies were identified by searching Pub Med for relevant articles published up to December 2022. The following search terms were used: “pancreaticoduodenectomy”, “pancreaticojejunostomy”, “pancreaticogastrostomy”, “gastric emptying”, “gastroparesis” and “postoperative complications”. The search was limited to English publications. Additional articles were identified by a manual search of references from key articles. Results: In recent years, various surgical procedures and techniques have been explored to reduce the incidence of DGE. Pyloric resection, Billroth II reconstruction, Braun's enteroenterostomy, and antecolic reconstruction may be associated with a decreased incidence of DGE, but more high-powered studies are needed in the future. Neither laparoscopic nor robotic surgery has demonstrated superiority in preventing DGE, and the use of staplers is controversial regarding whether they can reduce the incidence of DGE. Conclusions: Despite many innovations in surgical techniques, there is no surgical procedure that is superior to others to reduce DGE. Further larger prospective randomized studies are needed.

A nonlocal dispersal and time delayed HIV infection model with general incidences

Biologically,because of the impact of reproduction period and nonlocal dispersal of HIV-infected cells,time delay and spatial heterogeneity should be considered.In this paper,we establish an HIV infection model with nonlocal dispersal and infection age.Moreover,applying the theory of Fourier transformation and von Foerster rule,we transform the model to an integrodifferential equation with nonlocal time delay and dispersal.The well-posedness,positivity,and boundedness of the solution for the model are studied.

Bifurcation and Stability Analysis of Time-Delayed Wheelset System under White Noise Excitation

Considering the impact of time delay in the lateral stiffness of the primary suspension and stochastic disturbances of equivalent conicity on the wheelset system, a stochastic time-delayed wheelset system is established. The wheelset system is transformed into a onedimensional Ito stochastic differential equation using central manifold and stochastic averaging methods. The analysis of the system's stochastic stability is conducted through the maximum Lyapunov exponent and singular boundary theory. The combination of the stationary probability density method and numerical simulation is employed to discuss the types and conditions of stochastic P-bifurcation in the wheelset system. The results indicate that changes in speed and time delay induce stochastic P-bifurcations in the wheelset system, while changes in noise intensity do not lead to stochastic P-bifurcations. Both time delay and equivalent conicity affect the critical speed of the wheelset system, and the critical speed gradually increases with the decrease of time delay and equivalent conicity.

Designing Proportional-Integral Consensus Protocols for Second-Order Multi-Agent Systems Using Delayed and Memorized State Information

This paper is concerned with consensus of a secondorder linear time-invariant multi-agent system in the situation that there exists a communication delay among the agents in the network.A proportional-integral consensus protocol is designed by using delayed and memorized state information.Under the proportional-integral consensus protocol,the consensus problem of the multi-agent system is transformed into the problem of asymptotic stability of the corresponding linear time-invariant time-delay system.Note that the location of the eigenvalues of the corresponding characteristic function of the linear time-invariant time-delay system not only determines the stability of the system,but also plays a critical role in the dynamic performance of the system.In this paper,based on recent results on the distribution of roots of quasi-polynomials,several necessary conditions for Hurwitz stability for a class of quasi-polynomials are first derived.Then allowable regions of consensus protocol parameters are estimated.Some necessary and sufficient conditions for determining effective protocol parameters are provided.The designed protocol can achieve consensus and improve the dynamic performance of the second-order multi-agent system.Moreover,the effects of delays on consensus of systems of harmonic oscillators/double integrators under proportional-integral consensus protocols are investigated.Furthermore,some results on proportional-integral consensus are derived for a class of high-order linear time-invariant multi-agent systems.

A Dynamical Study of Modeling the Transmission of Typhoid Fever throughDelayed Strategies

This study analyzes the transmission of typhoid fever caused by Salmonella typhi using a mathematical model thathighlights the significance of delay in its effectiveness.Time delays can affect the nature of patterns and slow downthe emergence of patterns in infected population density.The analyzed model is expanded with the equilibriumanalysis,reproduction number,and stability analysis.This study aims to establish and explore the non-standardfinite difference(NSFD)scheme for the typhoid fever virus transmission model with a time delay.In addition,the forward Euler method and Runge-Kutta method of order 4(RK-4)are also applied in the present research.Some significant properties,such as convergence,positivity,boundedness,and consistency,are explored,and theproposed scheme preserves all the mentioned properties.The theoretical validation is conducted on how NSFDoutperforms other methods in emulating key aspects of the continuous model,such as positive solution,stability,and equilibrium about delay.Hence,the above analysis also shows some of the limitations of the conventional finitedifference methods,such as forward Euler and RK-4 in simulating such critical behaviors.This becomes moreapparent when using larger steps.This indicated that NSFD is beneficial in identifying the essential characteristicsof the continuous model with higher accuracy than the traditional approaches.

Awake rabbit model of ischemic spinal cord injury with delayed paraplegia:The role of ambient temperature

Background:Paraplegia after spinal cord ischemia is a devastating condition in the clinic.Here,we develop an awake rabbit model of spinal cord ischemia with delayed paraplegia and explore the influence of ambient temperature on the outcomes after injury.Methods:A total of 47 male rabbits were involved in the present study.Transient spinal cord ischemia was induced by occluding the infrarenal abdominal aorta of awake rabbits at different ambient temperatures.To find the optimal conditions for developing delayed paraplegia,hindlimb motor function after ischemia was evaluated between experiments.Results:The onset and magnitude of ischemic injury varied with the ambient temperature maintained during the peri-i schemia period.More serious spinal cord injury occurred when ischemia was induced at higher temperatures.At 18°C,25-minute ischemia resulted in 74%of rabbits developing delayed paraplegia.At a temperature of 28°C or higher,most of the animals developed acute paraplegia immediately.While at 13°C,rabbits usually regained normal motor function without paraplegia.Conclusion:This awake rabbit model is highly reproducible and will be helpful in future studies of delayed paraplegia after spinal cord ischemia.The ambient temperature must be considered while using this model during investigation of therapeutic interventions.

Numerical Analysis of Bacterial Meningitis Stochastic Delayed Epidemic Model through Computational Methods

Based on theWorld Health Organization(WHO),Meningitis is a severe infection of the meninges,the membranes covering the brain and spinal cord.It is a devastating disease and remains a significant public health challenge.This study investigates a bacterial meningitis model through deterministic and stochastic versions.Four-compartment population dynamics explain the concept,particularly the susceptible population,carrier,infected,and recovered.The model predicts the nonnegative equilibrium points and reproduction number,i.e.,the Meningitis-Free Equilibrium(MFE),and Meningitis-Existing Equilibrium(MEE).For the stochastic version of the existing deterministicmodel,the twomethodologies studied are transition probabilities and non-parametric perturbations.Also,positivity,boundedness,extinction,and disease persistence are studiedrigorouslywiththe helpofwell-known theorems.Standard and nonstandard techniques such as EulerMaruyama,stochastic Euler,stochastic Runge Kutta,and stochastic nonstandard finite difference in the sense of delay have been presented for computational analysis of the stochastic model.Unfortunately,standard methods fail to restore the biological properties of the model,so the stochastic nonstandard finite difference approximation is offered as an efficient,low-cost,and independent of time step size.In addition,the convergence,local,and global stability around the equilibria of the nonstandard computational method is studied by assuming the perturbation effect is zero.The simulations and comparison of the methods are presented to support the theoretical results and for the best visualization of results.

Follow-up strategy for early detection of delayed pseudoaneurysms in patients with blunt traumatic spleen injury: A single-center retrospective study

BACKGROUND The spleen is the most commonly injured solid organ in blunt abdominal trauma,and splenic pseudoaneurysm rupture is associated with a high risk of mortality.Nonoperative management has become the standard treatment for hemodynam-ically stable patients with splenic injuries.On the other hand,delayed splenic pseudoaneurysms can develop in any patient,and at present,there are no known risk factors that may reliably predict their occurrence.Furthermore,there is a lack of consensus regarding the most appropriate strategies for monitoring and mana-ging splenic injuries,especially lower-grade(I-III).AIM To determine the predictors of pseudo-aneurysm formation following splenic injury and develop follow-up strategies for early detection of pseudoaneurysms.METHODS We retrospectively analyzed patients who visited the Level I Trauma Center bet-ween January 2013 and December 2022 and were diagnosed with spleen injuries after blunt abdominal trauma.RESULTS Using the American Association for the Surgery of Trauma spleen injury scale,the splenic injuries were categorized into the following order based on severity:Grade I(n=57,17.6%),grade II(n=114,35.3%),grade III(n=89,27.6%),grade IV(n=50,15.5%),and grade V(n=13,4.0%).Of a total of 323 patients,35 underwent splenectomy and 126 underwent angioembolization.19 underwent delayed angioembolization,and 5 under-went both initial and delayed angioem-bolization.In 14 patients who had undergone delayed angioembolization,no extravasation or pseudoaneurysm was observed on the initial computed tomography scan.There are no particular patient-related risk factors for the formation of a delayed splenic pseudoaneurysm,which can occur even in a grade I spleen injury or even 21 days after the injury.The mean detection time for a delayed pseudoaneurysm was 6.26±5.4(1-21,median:6,inter-quartile range:2-9)days.CONCLUSION We recommend regular follow-up computed tomography scans,including an arterial and portal venous phase,at least 1 week and 1 month after injury in any grade of blunt traumatic spleen injury for the timely detection of delayed pseudoaneurysms.

Delayed diagnosis in inflammatory bowel disease:Time to consider solutions

In this editorial,we discuss a recently published manuscript by Blüthner et al in the World Journal of Gastroenterology,with a specific focus on the delayed diagnosis of inflammatory bowel disease(IBD).IBD,which includes Crohn's disease and ulcerative colitis,is a chronic intestinal disorder.A time lag may exist between the onset of inflammation and the appearance of signs and symptoms,potentially leading to an incorrect or delayed diagnosis,a situation referred to as the delayed diagnosis of IBD.Early diagnosis is crucial for effective patient treatment and prognosis,yet delayed diagnosis remains common.The reasons for delayed diagnosis of IBD are numerous and not yet fully understood.One key factor is the nonspecific nature of IBD symptoms,which can easily be mistaken for other conditions.Additionally,the lack of specific diagnostic methods for IBD contributes to these delays.Delayed diagnosis of IBD can result in numerous adverse consequences,including increased intestinal damage,fibrosis,a higher risk of colorectal cancer,and a decrease in the quality of life of the patient.Therefore,it is essential to diagnose IBD promptly by raising physician awareness,enhancing patient education,and developing new diagnostic methods.

Delayed treatment of diabetic foot ulcer in patients with type 2 diabetes and its prediction model

BACKGROUND Diabetic foot(DF)is a serious complication of type 2 diabetes.This study aimed to investigate the factors associated with DF occurrence and the role of delayed medical care in a cohort of patients with type 2 diabetes.AIM To reveal the impact of delayed medical treatment on the development of DF in patients with type 2 diabetes and to establish a predictive model for DF.METHODS In this retrospective cohort study,292 patients with type 2 diabetes who underwent examination at our hospital from January 2023 to December 2023 were selected and divided into the DF group(n=82,DF)and nondiabetic foot group(n=210,NDF).Differential and correlation analyses of demographic indicators,laboratory parameters,and delayed medical treatment were conducted for the two groups.Logistic regression was applied to determine influencing factors.Receiver operating characteristic(ROC)analysis was performed,and indicators with good predictive value were selected to establish a combined predictive model.RESULTS The DF group had significantly higher body mass index(BMI)(P<0.001),disease duration(P=0.012),plasma glucose levels(P<0.001),and HbA1c(P<0.001)than the NDF group.The NDF group had significantly higher Acute Thrombosis and Myocardial Infarction Health Service System(ATMHSS)scores(P<0.001)and a significantly lower delayed medical treatment rate(72.38%vs 13.41%,P<0.001).BMI,duration of diabetes,plasma glucose levels,HbA1c,diabetic peripheral neuropathy,and nephropathy were all positively correlated with DF occurrence.ATMHSS scores were negatively correlated with delayed time to seek medical treatment.The logistic regression model revealed that BMI,duration of diabetes,plasma glucose levels,HbA1c,presence of diabetic peripheral neuropathy and nephropathy,ATMHSS scores,and delayed time to seek medical treatment were influencing factors for DF.ROC analysis indicated that plasma glucose levels,HbA1c,and delayed medical treatment had good predictive value with an area under the curve of 0.933 for the combined predictive model.CONCLUSION Delayed medical treatment significantly affects the probability of DF occurrence in patients with diabetes.Plasma glucose levels,HbA1c levels,and the combined predictive model of delayed medical treatment demonstrate good predictive value.

Delayed neurological dysfunction following posterior laminectomy with lateral mass screw fixation:A case report and review of literature

BACKGROUND While most complications of cervical surgery are reversible,some,such as symptomatic postoperative spinal epidural hematoma(SEH),which generally occurs within 24 h,are associated with increased morbidity and mortality.Delayed neurological dysfunction is diagnosed in cases when symptoms present>3 d postoperatively.Owing to its rarity,the risk factors for delayed neurological dysfunction are unclear.Consequently,this condition can result in irreversible neurological deficits and serious consequences.In this paper,we present a case of postoperative SEH that developed three days after hematoma evacuation.CASE SUMMARY A 68-year-old man with an American Spinal Injury Association(ASIA)grade C injury was admitted to our hospital with neck pain and tetraplegia following a fall.The C3-C7 posterior laminectomy and the lateral mass screw fixation surgery were performed on the tenth day.Postoperatively,the patient showed no changes in muscle strength or ASIA grade.The patient experienced neck pain and subcutaneous swelling on the third day postoperatively,his muscle strength decreased,and his ASIA score was grade A.Magnetic resonance imaging showed hypointense signals on T1 weighted image(T1WI)and T2WI located behind the epidural space,with spinal cord compression.Emergency surgical intervention for the hematoma was performed 12 h after onset.Although hypoproteinemia and pleural effusion did not improve in the perioperative period,the patient recovered to ASIA grade C on day 30 after surgery,and was transferred to a functional rehabilitation exercise unit.CONCLUSION This case shows that amelioration of low blood albumin and pleural effusion is an important aspect of the perioperative management of cervical surgery.Surgery to relieve the pressure on the spinal cord should be performed as soon as possible to decrease neurological disabilities.

A Case Report and Literature Review: A Case of Delayed Bile Leakage Following Laparoscopic Cholecystectomy

Background: Delayed bile leakage after laparoscopic cholecystectomy, defined as occurring more than 72 hours after surgery, is a rare and serious complication of laparoscopic cholecystectomy, with an incidence rate of 0.060%. Case Declaration: This case report details a patient diagnosed with delayed bile leakage 43 days after laparoscopic cholecystectomy. The patient was discharged from our hospital after undergoing CT-guided puncture treatment, with no obvious complications identified. The patient was monitored for one year following the procedure, during which time no significant discomfort was reported. Objective: This case report is to analyse and review the clinical manifestations, diagnosis, treatment and prevention of delayed bile leakage after cholecystectomy, with reference to the relevant literature. Results: Delayed bile leakage after laparoscopic cholecystectomy can be prevented, although not eliminated. It is recommended that the operator treat the operation with caution, avoid taking risks, and adhere to careful procedures and strict separation according to the requirements. This approach is key to preventing late bile leakage in the postoperative period.

Early clinical outcomes of two regimens of prophylactic antibiotics in cardiac surgical patients with delayed sternal closure

BACKGROUND Delayed sternal closure(DSC)can be a lifesaving approach for certain patients who have undergone cardiac surgery.The value of the type of prophylactic antibiotics in DSC is still debatable.AIM To investigate clinical outcomes of different prophylactic antibiotic regimens in patients who had DSC after cardiac surgery.METHODS This was a retrospective observational single-center study.Fifty-three consecutive patients who underwent cardiac surgery and had an indication for DSC were included.Patients were subjected to two regimens of antibiotics:Narrow-spectrum and broad-spectrum regimens.RESULTS The main outcome measures were length of hospital and intensive care unit(ICU)stay,duration of mechanical ventilation,and mortality.Of the 53 patients,12(22.6%)received narrow-spectrum antibiotics,and 41(77.4%)received broad-spectrum antibiotics.The mean age was 59.0±12.1 years,without significant differences between the groups.The mean duration of antibiotic use was significantly longer in the broad-spectrum than the narrowspectrum group(11.9±8.7 vs 3.4±2.0 d,P<0.001).The median duration of open chest was 3.0(2.0-5.0)d for all patients,with no difference between groups(P=0.146).The median duration of mechanical ventilation was significantly longer in the broad-spectrum group[60.0(Δinterquartile range(IQR)170.0)h vs 50.0(ΔIQR 113.0)h,P=0.047].Similarly,the median length of stay for both ICU and hospital were significantly longer in the broadspectrum group[7.5(ΔIQR 10.0)d vs 5.0(ΔIQR 5.0)d,P=0.008]and[27.0(ΔIQR 30.0)d vs 19.0(ΔIQR 21.0)d,P=0.031].Five(9.8%)patients were readmitted to the ICU and 18(34.6%)patients died without a difference between groups.CONCLUSION Prophylactic broad-spectrum antibiotics did not improve clinical outcomes in patients with DSC post-cardiac surgery but was associated with longer ventilation duration,length of ICU and hospital stays vs narrow-spectrum antibiotics.

Early versus delayed necrosectomy in pancreatic necrosis:A population-based cohort study on readmission,healthcare utilization,and in-hospital mortality

BACKGROUND Acute necrotizing pancreatitis is a severe and life-threatening condition.It poses a considerable challenge for clinicians due to its complex nature and the high risk of complications.Several minimally invasive and open necrosectomy procedures have been developed.Despite advancements in treatment modalities,the optimal timing to perform necrosectomy lacks consensus.AIM To evaluate the impact of necrosectomy timing on patients with pancreatic necrosis in the United States.METHODS A national retrospective cohort study was conducted using the 2016-2019 Nationwide Readmissions Database.Patients with non-elective admissions for pancreatic necrosis were identified.The participants were divided into two groups based on the necrosectomy timing:The early group received intervention within 48 hours,whereas the delayed group underwent the procedure after 48 hours.The various intervention techniques included endoscopic,percutaneous,or surgical necrosectomy.The major outcomes of interest were 30-day readmission rates,healthcare utilization,and inpatient mortality.RESULTS A total of 1309 patients with pancreatic necrosis were included.After propensity score matching,349 cases treated with early necrosectomy were matched to 375 controls who received delayed intervention.The early cohort had a 30-day readmission rate of 8.6% compared to 4.8%in the delayed cohort(P=0.040).Early necrosectomy had lower rates of mechanical ventilation(2.9%vs 10.9%,P<0.001),septic shock(8%vs 19.5%,P<0.001),and in-hospital mortality(1.1%vs 4.3%,P=0.01).Patients in the early intervention group incurred lower healthcare costs,with median total charges of $52202 compared to$147418 in the delayed group.Participants in the early cohort also had a relatively shorter median length of stay(6 vs 16 days,P<0.001).The timing of necrosectomy did not significantly influence the risk of 30-day readmission,with a hazard ratio of 0.56(95%confidence interval:0.31-1.02,P=0.06).CONCLUSION Our findings show that early necrosectomy is associated with better clinical outcomes and lower healthcare costs.Delayed intervention does not significantly alter the risk of 30-day readmission.

Efficacy of Mometasone Furoate Nasal Spray in Delayed Antibiotic Prescriptions for Acute Rhinosinusitis: A Multicenter, Randomized, Open-Label, Comparative, Prospective, Parallel Group Study

While their clinical presentation is similar, post-viral rhinosinusitis does not indicate the possible development of bacterial rhinosinusitis which occurs in only 0.5% to 5% of all cases of ARS. However, unreasonable antibacterial therapy is prescribed in 54% to 77% of cases. The perspective is to use delayed antibacterial therapy management. The purpose of the study was to investigate the efficacy of mometasone furoate nasal spray within the delayed prescription approach. Methods: A multicenter, randomized, open-label, comparative, prospective, parallel group study enrolled a total of 156 patients with ARS aged 18 to 60 years, of them 155 patients completed the study. The patients were randomized into the main group of Mometasone Furoate (Flix) Nasal Spray or into the control group of amoxicillin clavulanate tablets while both groups were administered a standard ARS therapy. Findings: The use of MF nasal spray within the delayed antibiotics prescription approach has a significantly higher efficacy compared to the immediate antibiotics prescription in the first days of treatment (p < 0.05). Antibacterial therapy was prescribed to 42.3% of patients in the main group compared to 100.0% of patients in the control group (p < 0.05). It was shown that there were statistically significant differences in the dynamics of changes in the total symptom score between the patients administered antibiotics and the antibiotic-naive patients. Conclusion: The use of MF within the delayed antibiotics prescription approach reliably improves the pattern of symptoms over time at the disease onset and significantly reduces the need for NSAIDs administration and antibiotics prescription frequency.

Delayed Pseudoaneurysms of Vertebral Artery Post Penetrating Trauma: A Case Report

Objective: Vascular injuries usually present immediately after the penetration, but the delayed onset of vascular symptoms caused by vessel dissection or aneurysm after a traumatic event is extremely rare. Vertebral artery injury is a low-frequency but high-mortality injury. We aim to report evidence of delayed onset of vascular symptoms following penetrating trauma in the neck. Materials and Methods: A case report. Results: A 19-year-old boy was referred to our hospital and complained of a mass in the right part of his neck (right mandibular angle). He gave a history of penetrating trauma to his neck 2 months ago. The mass was expanding during these 2 months and doesn’t respond to antibiotic therapy. In the examination, 3 × 3 cm, firm, nonmobile, and without tenderness and pain mass was palpated in the second level of his neck. Doctors ordered a Doppler sonography in the hospital where a yin-yang pattern was reported. A 36 × 43 × 40 mm heterogeneous, solid, and hypodense area close to C1-C2-C3 with vascular flow was discovered in the right submandibular area after computed tomography (CT)-angiography. The patient was referred to an interventional neurologist for angiography and due to the lack of flow at the distal of the V3 segment, he decided to sacrifice this artery by two coils. Conclusion: Penetrating neck injuries are usually asymptomatic, but these injuries are often accompanied by hemorrhage, neurological symptoms, dysphagia, odynophagia, and windpipe. Penetrating lesions of the vertebral artery are rare and very difficult to diagnose. Also, these lesions are challenging for surgeons due to complex anatomy and difficult surgical exposure. So, endovascular treatment was used to treat the patient.

Delayed Grafting as a Valid Technique in Burn Management: Experience from a Burn Unit in Oman

Background: Early excision and grafting has been the preferred method of managing major burns around the world since 1970. Considering the advances in health care and the development of new antibiotics over the past 50 years, delayed grafting as a technique for the management of burns over 15%-20% of total body surface area (TBSA) could have comparable results to that of early excision. This study aims to highlight the outcomes of practicing delayed grafting in burn patients. Methods: A case series analysis was performed of 51 patients who were admitted to the burns unit in Sultan Qaboos Hospital Salalah with over 20% TBSA between January 2014 and December 2019. The patients received prophylactic antibiotics and silver sulphadiazine dressing until the burn eschar had completely separated, followed by grafting. Results: Two patients were lost during the entire duration of the study. The mortality rate was comparable to that of early excision, while the rate of hypertrophic scarring was lower than the range reported by other studies. Conclusion: In the management of patients with over 20% TBSA, delayed grafting after complete separation of eschar is still a valid technique.

Refinement of the Proposed Gamma-Ray Burst Time Delay Model

This paper is the second instalment in our study of the observed time delay in the arrival times of radio photons emanating from Gamma Ray Bursts (GRBs). The mundane assumption in contemporary physics as to the cause of these pondersome time delays is that they are a result of the photon being endowed with a non-zero mass. While we do not rule out the possibility of a non-zero mass for the photon, our working assumption is that the major cause of these time delays may very well be that these photons are travelling in a rarefied cosmic plasma in which the medium’s electrons interact with the electric component of the Photon, thus generating tiny currents that lead to dispersion, hence, a frequency-dependent speed of Light (FDSL). In the present instalment, we “improve” on the model presented in the first instalment by dropping the assumption that the resultant pairs of these radio photons leave the shock front simultaneously. The new assumption of a non-simultaneous— albeit systematic—emission of these photon pairs allows us to obtain a much more convincing and stronger correlation in the time delay. This new correlation allows us to build a unified model for the four GRBs in our sample using a relative distance correction mechanism. The new unified model allows us to obtain as our most significant result a value for the frequency equivalence of the interstellar medium (ISM)’s conductance ν* ~ 1.500 ± 0.009 Hzand also an independent distance measure to the GRBs where we obtain for our four GRB samples an average distance of: ~69.40 ± 0.10, 40.00 ± 0.00, 58.40 ± 0.40, and 86.00 ± 1.00 Mpc, for GRB 030329, 980425, 000418 and 021004 respectively.

Stability of a Delayed Stochastic Epidemic COVID-19 Model with Vaccination and with Differential Susceptibility

In this paper, we treat the spread of COVID-19 using a delayed stochastic SVIRS (Susceptible, Infected, Recovered, Susceptible) epidemic model with a general incidence rate and differential susceptibility. We start with a deterministic model, then add random perturbations on the contact rate using white noise to obtain a stochastic model. We first show that the delayed stochastic differential equation that describes the model has a unique global positive solution for any positive initial value. Under the condition R0 ≤ 1, we prove the almost sure asymptotic stability of the disease-free equilibrium of the model.