Ab Initio Study of the Graphyne-like γ-SiC Nanoflake for Toxic Gas-Sensing Applications.

This study focuses on the geometrical, electronic, and optical properties of the γ-graphyne-like novel γ-SiC nanoflake of the γ-silicon carbide (SiC) monolayer using density functional theory calculations. γ-SiC was revealed to be a stable semiconducting nanoflake confirmed by a negative cohesive energy, real vibrational frequencies, and a 1.749 eV energy gap. The adsorption of COCl2, HCN, PH3, AsH3, CNCl, and C2N2 toxic gases on the γ-SiC nanoflake is also studied, which revealed an attractive gas-nanoflake interaction with the adsorption energy ranging from -0.21 to -0.38 eV. The adsorption results in a significant charge transfer between gas-adsorbent complexes. A significant variation in the energy gap and electrical conductivity was observed due to gas adsorption. γ-SiC showed maximum sensitivity at room temperature for CNCl gas. The entire process of adsorption is exothermic and thermodynamically stable. γ-SiC showed a high absorption coefficient over 104 orders with a significant variation in the absorption peak intensity and blue peak shifting. According to the quantum theory and reduced density gradient analysis, all of the gases are physisorbed on the γ-SiC nanoflake due to van der Waals interactions. The obtained results signify the usability of γ-SiC as a potential toxic gas sensor.

Phosphorus-doped T-graphene nanocapsule toward O3 and SO2 gas sensing: a DFT and QTAIM analysis.

Tetragonal graphene nano-capsule (TGC), a novel stable carbon allotrope of sp2 hybridization is designed and doped with phosphorus (P) to study the O3 and SO2 gas sensitivity via density functional theory calculation. Real frequencies verified the natural existence of both TGC and P-doped TGC (PTGC). Both TGC and PTGC suffer structural deformations due to interaction with O3 and SO2 gases. The amount of charge transfer from the adsorbent to the gas molecule is significantly greater for O3 adsorption than SO2 adsorption. The adsorption energies for TGC + O3 and PTGC + O3 complexes are - 3.46 and - 4.34 eV respectively, whereas for TGC + SO2 and PTGC + SO2 complexes the value decreased to - 0.29 and - 0.30 eV respectively. The dissociation of O3 is observed via interaction with PTGC. A significant variation in electronic energy gap and conductivity results from gas adsorption which can provide efficient electrical responses via gas adsorption. The blue/red shift in the optical response proved to be a way of detecting the types of adsorbed gases. The adsorption of O3 is exothermic and spontaneous whereas the adsorption of SO2 is endothermic and non-spontaneous. The negative change in entropy verifies the thermodynamic stability of all the complexes. QTAIM analysis reveals strong covalent or partial covalent interactions between absorbent and adsorbate. The significant variation in electrical and optical response with optimal adsorbent-gas interaction strength makes both TGC and PTGC promising candidates for O3 and SO2 sensing.

A first principles study of RbSnCl3 perovskite toward NH3, SO2, and NO gas sensing.

The sensitivity of a RbSnCl3 perovskite 2D layer toward NH3, SO2, and NO toxic gases has been studied via DFT analysis. The tri-atomic layer of RbSnCl3 possessed a tetragonal symmetry with a band gap of 1.433 eV. The adsorption energies of RbSnCl3 for NH3, SO2 and NO are -0.09, -0.43, and -0.56 eV respectively with a recovery time ranging from 3.4 × 10-8 to 3.5 ms. RbSnCl3 is highly sensitive toward SO2 and NO compared to NH3. The adsorption of SO2 and NO results in a significant structural deformation and a semiconductor-to-metal transition of RbSnCl3 perovskite. A high absorption coefficient (>103 cm-1), excessive optical conductivity (>1014 s-1), and a very low reflectivity (<3%) make RbSnCl3 a potential candidate for numerous optoelectronic applications. A significant shift in optical responses is observed through SO2 and NO adsorption, which can enable identification of the adsorbed gases. The studied characteristics signify that RbSnCl3 can be a potential candidate for SO2 and NO detection.

Green synthesis of zinc oxide nano particles using Allium cepa L. waste peel extracts and its antioxidant and antibacterial activities.

Synthesis of nanoparticles through the green approach using plant and vegetable extracts has gained popularity since they are thought to be efficient and cost-effective materials. This study is designed to synthesize zinc oxide nanoparticles (ZnO-NPs) from onion waste peel extract (Allium cepa L.) via the green synthesis approach. The synthesized ZnO-NPs were characterized by utilizing the UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), Energy Dispersive X-ray (EDX), Field Emission Scanning Electron Microscopy (FE-SEM) and X-ray Powder Diffraction (XRD)techniques. The nanoparticles formation was confirmed by the UV-Vis sharp absorption spectra at 318 and 322 nm. The synthesized ZnO-NPs size and shape was revealed by the XRD and SEM respectively. Smallest nanoparticle average crystallite size was found 57.38 nm with hexagonal shape. The bioactive functional groups that are in charge of capping and stabilizing the ZnO-NPs was assured by the FTIR data. Further, prepared ZnO-NPs were used to assess their possible antioxidant and antibacterial properties. DPPH test for free radical scavenging showed potential antioxidant properties of the synthesized ZnO-NPs. The antibacterial activity were studied against three clinical strains: P. aeruginosa, E. coli, and S. aureus with the maximum zone of inhibition 13.17 mm, 22.00 mm and 12.35 mm respectively at 100 µg/mL subsequently minimum inhibitory concentration was found 50 µg/mL for P. aeruginosa, and S. aureus whereas 100 µg/mL for E. coli. Antioxidant and antibacterial activity tests appear bio-resource based ZnO-NPs from Allium cepa L. extract have effects on free radical and growth of microorganisms.Therefore, it could be a promising candidates for agricultural and food safety applications as an effective antimicrobial agent against pathogenic microorganisms and also can address future biomedical applications after complete in vivo study.

Primary Retroperitoneal Serous Cyst Adenoma: A Case Report and Literature Review.

Primary retroperitoneal serous cyst adenomas (PRSCs) are extremely rare thin-walled cystic lesions whose pathogenesis is not well understood. Clinical presentation varies depending on the lesion's size and location, i.e., larger lesions compress adjacent organs, giving the impression of malignancy. Although advances in imaging techniques enable to identify various characteristics of retroperitoneal cystic lesions, there are no pathognomonic signs to confirm the diagnosis. The exact diagnosis is based on the histology after complete surgical excision. An open surgical approach is considered the traditional method of complete resection; however, laparoscopic techniques have increasingly been employed. Diagnostic aspiration is discouraged due to the potential risk of seeding if the lesion is malignant. We present the case of a 51-year-old woman who underwent complete excision of a large right retroperitoneal cyst, histologically confirmed as PRSC with a review of the background and management options of this phenomenon.

Necrotizing Soft Tissue Infections of the Breast: A Potentially Lethal Surgical Emergency.

Necrotizing soft tissue infection (NSTI) of the breast is an extremely rare event in surgical practice. It is considered the most aggressive form of soft tissue infection and a true surgical emergency. It is also associated with a high risk of mortality if not diagnosed promptly. Few cases have been documented in the literature; the exact etiology and risk factors vary from those involving the limbs, trunk, and perineum. Early recognition, prompt surgical treatment, and broad-spectrum antibiotic therapy are crucial for reducing morbidity and mortality. These reports present cases of NSTIs in breasts with unique etiologies and challenges in their management.

Gender Influence on Abdominal Aortic Aneurysm Surgery in a Caribbean Population.

Female patients with abdominal aortic aneurysms (AAAs) are usually less common and older than their male counterparts. We report on AAA disease in a Caribbean nation with respect to gender and review their outcomes relative to the male population. Data were collected prospectively and analyzed retrospectively for patients with AAAs who underwent surgery from 2001 to 2018. Sixty patients were diagnosed with AAA with 44 going on to have surgical repair of which 35 were males, aged 61 to 89 (mean age 73.4 years). Nine women ages 44 to 74 years (mean age 60.8 years) had surgical intervention, three being between 40 and 49 years. The size of aneurysms in these patients ranged from 4.3 to 11.0 cm in diameter (average 6.95 cm), female patients having an average diameter of 6.7 cm. Of the 44 patients, 43 underwent open and one endovascular repair. Thirty-three were elective cases and 11 were ruptured with 32 aorto-aortic and 13 aorto-iliac repairs. There were nine fatalities, three elective and six ruptured, with only one being female. Women had similar outcomes to men in all age groups with young patients having good results. Female AAA patients are usually older, undergo less surgical procedures especially if endovascular, and have worse outcomes than their male counterparts. Our study showed that the females were younger but had similar outcomes to the male patients. The female Caribbean patients may present at much younger ages than in continental populations and this may be due to genetic, ethnic, or lifestyle factors.

Iron restriction induces the small-colony variant phenotype in Staphylococcus aureus.

Pathogens such as Staphylococcus aureus must overcome host-induced selective pressures, including limited iron availability. To cope with the harsh conditions of the host environment, S. aureus can adapt its physiology in multiple ways. One of these adaptations is the fermenting small-colony variant (SCV) phenotype, which is known to be inherently tolerant to certain classes of antibiotics and heme toxicity. We hypothesized that SCVs might also behave uniquely in response to iron starvation since one of the major cellular uses of iron is the respiration machinery. In this study, a respiring strain of S. aureus and fermenting SCV strains were treated with different concentrations of the iron chelator, 2,2' dipyridyl (DIP). Our data demonstrate that a major impact of iron starvation in S. aureus is the repression of respiration and the induction of the SCV phenotype. We demonstrate that the SCV phenotype transiently induced by iron starvation mimics the aminoglycoside recalcitrance exhibited by genetic SCVs. Furthermore, prolonged growth in iron starvation promotes increased emergence of stable aminoglycoside-resistant SCVs relative to the naturally occurring subpopulation of SCVs within an S. aureus community. These findings may have relevance to physiological and evolutionary processes occurring within bacterial populations infecting iron-limited host environments.

Density functional theory study of Mobius boron-carbon-nitride as potential CH4, H2S, NH3, COCl2 and CH3OH gas sensor.

The interesting properties of Mobius structure and boron-carbon-nitride (BCN) inspired this research to study different characteristics of Mobius BCN (MBCN) nanoribbon. The structural stability and vibrational, electrical and optical properties are analysed using the density functional theory. The gas-sensing ability of the modelled MBCN structure was also studied for methane, hydrogen sulfide, ammonia, phosgene and methanol gases. The negative adsorption energy and alteration of electronic bandgap verified that MBCN is very sensitive toward the selected gases. The complex structures showed a high absorption coefficient with strong chemical potential and 7 ps-0.3 ms recovery time. The negative change in entropy signifies that all the complex structures were thermodynamically stable. Among the selected gases, the MBCN showed the strongest interaction with methanol gas.

Prevalence of multiple non-communicable diseases risk factors among adolescents in 140 countries: A population-based study.

Background: Modifiable non-communicable disease (NCD) risk factors are becoming increasingly common among adolescents, with clustering of these risk factors in individuals of particular concern. The aim of this study was to assess global status of clustering of common modifiable NCD risk factors among adolescents. Methods: We used latest available data from nationally representative survey for 140 countries, namely the Global School-based Student Health Survey, the Health Behaviour in School-Aged Children and the longitudinal study of Australian Children. Weighted mean estimates of prevalence with corresponding 95% confidence intervals of nine NCD risk factors - physical inactivity, sedentary behaviour, insufficient fruits and vegetable consumption, carbonated soft drink consumption, fast food consumption, tobacco use, alcohol consumption and overweight/obesity - were calculated by country, region and sex. Findings: Over 487,565 adolescents, aged 11-17 years, were included in this study. According to trend analysis, prevalence of four or more NCD risk factors increased gradually over time. Prevalence of four or more NCD risk factors was 14.8% in 2003-2007 and increased to 44% in 2013-2017, an approximately three-fold increase (44.0%). Similar trends were also observed for three and two risk factors. Large variation between countries in the prevalence of adolescents with four or more risk factors was found in all regions. The country level range was higher in the South-East Asia Region (minimum Sri Lanka = 8%, maximum Myanmar = 84%) than Western Pacific Region (minimum China = 3%, maximum Niue = 72%), European Region (minimum Sweden = 13.9%, maximum Ireland = 66.0%), African Region (minimum Senegal = 0.8%, maximum Uganda = 82.1%) and Eastern Mediterranean Region (minimum Libya = 0.2%, maximum Lebanon = 80.2%). Insufficient vegetable consumption, insufficient fruit consumption and physically inactivity were three of the four most prevalent risk factors in all regions. Interpretation: Our results suggest a high prevalence of four or more NCD risk factors in adolescents globally, although variation was found between countries. Results from our study indicate that efforts to reduce adolescent NCD risk factors and the associated health burden need to be improved. These findings can assist policy makers to target the rollout of country- specific interventions. Funding: None.

Comment on 'Achenbach syndrome in an older man'.

We comment on a previous letter regarding Achenbach syndrome, and suggest that punch biopsy should be performed in all clinically suspected cases to obtain histological confirmation of the disease.

Determinants of Hepatitis B Virus (HBV) Infection Among University Students in Central Bangladesh.

This study aimed to determine the seroprevalence and determinants of hepatitis B virus (HBV) infection among university students in Bangladesh. This cross-sectional study was conducted among 614 students from five universities in central Bangladesh. Data were collected on demographic information, immunization history, medical and blood transfusion history through the face-to-face interview. Blood samples were collected and screened for anti-HBsAg using ELISA, HBsAg Rapid Test-cassette, and immune chromatographic test. The overall seroprevalence of HBV infection was 5.0%, and vaccination coverage was 19.2% among the participants. Students having a history of surgery (OR 11.004, 95% CI 3.211-37.707), blood transfusion (OR 5.651, 95% CI 0.965-33.068), being married (OR 4.776, 95% CI 1.508-15.127), and not being vaccinated (OR 9.825, 95% CI 1.130-85.367) were at higher risk of being infected by HBV. This study showed the endemicity of HBV infection among the Bangladeshi population. Marriage, surgical or blood transfusion history, not being vaccinated were the determinants of HBV infection within the study population. Public health initiatives for preventing HBV infection at the university levels should be envisaged.

Successful Hand Replantation Augmented by Delayed Pedicled Fascio-Cutaneous Groin Flap in an Adult Laborer: A Case Report and Literature Review.

BACKGROUND Upper limb replantation has become an almost routine procedure, with digital and hand reattachments being the most commonly performed. These remain challenging procedures to reconstructive surgeons, especially when there is trauma to the detached limb. Injury to the overlying skin and soft tissue can lead to tissue necrosis, sepsis, and loss of the replanted limb. The use of skin grafts as well as a wide variety of muscular, musculo-cutaneous, fascio-cutaneous flaps, and free-transfer grafts has significantly diminished limb loss. We report on the use of a delayed fascio-cutaneous, pedicled groin flap to cover a defect on the dorsum of a hand replanted 6 weeks earlier. CASE REPORT A right-hand-dominant male laborer had his left hand completely severed by a sharpened machete. This was surgically replanted with limb salvage but there was an area of denuded tissue on the dorsum, devoid of epidermal coverage. A fascio-cutaneous, pedicled rotational flap arising from the left groin was used as definitive cover for the defect. This flap augmented the replantation process by producing a functional and visually acceptable replant, allowing the patient to undergo rehabilitation and eventually return to the workforce. CONCLUSIONS The fascio-cutaneous, pedicled, rotational groin flap is a thin, pliable, but robust flap which covered the defect created by the initial injury with a protective tissue layer. It allowed free movement of the extensor tendons by creating a smooth surface over which they could easily glide with retention of near-normal, functional hand movement.

Necrotizing Fasciitis of the Breast Requiring a Life-Saving Mastectomy: A Case Report and Literature Review.

Necrotizing soft tissue infection of the breast is an extremely rare event in routine surgical practice. It is the most aggressive form of soft tissue infection and a real surgical emergency. It is associated with a high risk of mortality if not diagnosed promptly. A Literature search has revealed only a few such cases. The exact etiology is variable and very often multifactorial. Early recognition and prompt surgical treatment along with broad-spectrum antibiotic therapy are of paramount importance to prevent mortality. In this report, we present the first case of necrotizing fasciitis of the breast following an insect bite in the literature, in a 57-year-old diabetic patient with a delayed presentation that required a life-saving mastectomy.

Case report of metastatic breast cancer mimicking ileal Crohn's disease.

INTRODUCTION: Lobular breast cancer (LBC) has an increased risk of gastrointestinal (GI) spread compared with ductal breast carcinoma. Breast cancer commonly metastasises to bone, lung, liver, central nervous system and rarely to the gastrointestinal tract. As the prognosis for breast cancer continues to improve with modern medical practice it is important to be aware of the various clinical presentations and the appropriate management of breast cancer metastases. CASE PRESENTATION: We describe a case of a 60-year-old woman who presented with symptoms of bowel obstruction 30 months after undergoing mastectomy and adjuvant chemotherapy for LBC. A Computer Tomography (CT) scan showed terminal ileal thickening suggestive of Crohn's disease but histopathology revealed metastatic lobular carcinoma. Surgical resection to relieve her small bowel obstruction confirmed LBC. CLINICAL DISCUSSION: This case illustrates an unusual presentation of metastatic breast cancer causing small bowel obstruction with radiological features mimicking Crohn's disease. CONCLUSION: Patients with breast cancer can present with intestinal obstruction due to metastatic spread to the small intestine; this may resemble Crohn's disease clinically and radiologically.

Acute Upper Limb Ischemia: Prompt Surgery and Long-Term Anticoagulation Prevent Limb Loss and Debilitation.

BACKGROUND: Acute upper limb ischemia is an uncommon clinical manifestation of thromboembolism seen predominantly in patients with atrial fibrillation. Treatment can be by conservative or surgical means but the consensus is that after conservative treatment, symptoms still persist. In this series, an attempt was made at limb preservation and return to functional capacity by early surgery in all patients diagnosed with acute limb ischemia. METHODS: Patients referred with upper limb ischemia (22) were stratified into non-acute (6) treated with anticoagulation alone and those with acute ischemia. Sixteen (16) patients, age range 30-92 years (median 62.4 years) comprising mainly females (13), had clinical evidence of severe ischemia and underwent immediate brachial embolectomy with postoperative anticoagulation. RESULTS: Sixteen patients underwent 20 embolectomies with immediate reperfusion of limbs and relief of symptoms. Two patients had two re-operations each due to recurrent symptoms but both recovered with good outcome, one going on to have an axillary-radial bypass. There was no limb disability nor limb loss, but one postoperative mortality. All other patients were seen at their 1-year review and at 5 years, eleven out of 15 patients were still alive with most resuming an active lifestyle and some returning to work. CONCLUSION: Good outcomes were obtained in this series in both the short and long term. Despite one mortality, there was no limb loss nor disability in a mainly elderly population. Prompt surgery and meticulous long-term anticoagulation reduced complications and improved limb salvage rates ensuring that patients had a good quality of life after surgery.

Targeting JAK/STAT Signaling Antagonizes Resistance to Oncolytic Reovirus Therapy Driven by Prior Infection with HTLV-1 in Models of T-Cell Lymphoma.

Human T-cell leukemia virus type 1 (HTLV-1) is a retrovirus that infects at least 10 million people worldwide and is associated with the development of T-cell lymphoma (TCL). The treatment of TCL remains challenging and new treatment options are urgently needed. With the goal of developing a novel therapeutic approach for TCL, we investigated the activity of the clinical formulation of oncolytic reovirus (Reolysin, Pelareorep) in TCL models. Our studies revealed that HTLV-1-negative TCL cells were highly sensitive to Reolysin-induced cell death, but HTLV-1-positive TCL cells were resistant. Consistent with these data, reovirus displayed significant viral accumulation in HTLV-1-negative cells, but failed to efficiently replicate in HTLV-1-positive cells. Transcriptome analyses of HTLV-1-positive vs. negative cells revealed a significant increase in genes associated with retroviral infection including interleukin-13 and signal transducer and activator of transcription 5 (STAT5). To investigate the relationship between HTLV-1 status and sensitivity to Reolysin, we infected HTLV-1-negative cells with HTLV-1. The presence of HTLV-1 resulted in significantly decreased sensitivity to Reolysin. Treatment with the JAK inhibitor ruxolitinib suppressed STAT5 phosphorylation and expression of the key anti-viral response protein MX1 and enhanced the anti-TCL activity of Reolysin in both HTLV-1-positive and negative cells. Our data demonstrate that the inhibition of the JAK/STAT pathway can be used as a novel approach to antagonize the resistance of HTLV-1-positive cells to oncolytic virus therapy.

Congenital Dual Internal Hernias Causing Small Bowel Obstruction in a Man with no Prior Surgical History: A Report of a Very Rare Case.

BACKGROUND Internal hernias involve protrusion of the small bowel through a peritoneal or mesenteric space in the abdominal or pelvic cavity. Congenital internal small bowel hernias are rare and patients with them usually present with small bowel obstruction (SBO) at a young age, whereas in older patients, internal small bowel hernias usually are acquired secondary to previous surgery. The present report is of a rare case of SBO due to dual congenital internal small bowel hernias in a 51-year-old man with no history of abdominal surgery. CASE REPORT We report a case of dual congenital internal hernias of the small bowel in a patient who presented with symptoms and signs of SBO. He had no history of abdominal trauma, surgery, or comorbid conditions. His abdomen was mildly distended with minimal tenderness in the upper left quadrant but there was no guarding or rebound tenderness. Abdominal X-rays confirmed the SBO. A contrast-enhanced computed tomography scan of the patient's abdomen revealed SBO with transition at 2 points, suggestive of a closed-loop obstruction. However, the exact cause of the SBO was confirmed at laparotomy, which revealed dual internal hernias (intramesosigmoid and paraduodenal). The hernias were managed individually and the patient had a successful outcome after surgery. CONCLUSIONS Although the present report is of a rare presentation of internal small bowel hernia, the case underscores that patients with this condition may present with SBO. Successful surgical management requires knowledge of the intra-abdominal peritoneal spaces and management of the hernia sac.

Arterial Embolism in Malignancy: The Role of Surgery.

BACKGROUND: Peripheral arterial embolism from malignant disease is uncommon and a rare cause of limb ischemia. In the acute setting, patients can present with severe ischemia of either the upper or lower limb, and urgent surgical intervention is often required to avoid severe debilitation and limb loss. PATIENTS: Our case series comprised three patients who presented with upper and lower limb ischemia and were found to have concomitant malignancy. All three patients were female, with a median age of 54.3 years, and none of the patients was on active chemotherapy. One presented with stage IIb uterine carcinoma, one with stage IIIb ovarian carcinoma, and the other with stage IIIb cervical carcinoma. These patients were referred for vascular management, with two being acute and the other acute on chronic. RESULTS: Of the three patients, two presented with acute limb ischemia and underwent arterial thrombectomy, one of the upper and the other the lower limb. The third patient, with acute-on-chronic upper limb ischemia, was treated conservatively with intravenous heparin followed by oral anticoagulation. All three had limb salvage and survival outcome at 1 year post-treatment. CONCLUSION: In this small series, surgical intervention in two patients and conservative management in the other patient led to limb salvage with a reasonably good quality of life. Even though the long-term survival for patients with malignant disease is generally poor, surgical intervention can achieve limb salvage with a reasonably good quality of life.

Local Repair of a Secondary Aortoenteric Fistula in an Unstable Patient in a Resource-Poor Setting: A Case Report and Literature Review.

The presentation of a massive upper gastrointestinal bleed (UGIB) due to an aortoenteric fistula (AEF) is a rare occurrence. A high index of suspicion is required to rapidly make the diagnosis and execute prompt surgical management. Despite the many surgical options described, the survival rate continues to be low. Conventional surgical management is associated with a high morbidity and mortality. However, in emergencies, patients are unsuitable for major vascular surgery and may benefit from the less invasive staged procedure. This is a case report of a secondary aortoenteric fistula (SAEF) presenting as a massive UGIB, two years after an abdominal aortic aneurysm repair using a Dacron graft. Due to a lack of endovascular service in our setting, we proceeded with an upper gastrointestinal endoscopy followed by exploratory laparotomy. A damage control approach was chosen for our patient, i.e., local repair of the graft and aorta, as our patient was on double inotropes on the table. The patient died within 24 hours as a result of massive blood volume loss.