Chirality and length-dependent electron transmission of fullerene-capped chiral carbon nanotubes sandwiched in gold electrodes.

In order to develop high-performance CNT-based electronic and optoelectronic devices, it is crucial to establish the relationship between the electron transport properties of carbon nanotubes (CNTs) and their structures. In this work, we have investigated the transport properties of chiral (8, m) and (10, m) CNTs sandwiched between two gold electrodes by employing nonequilibrium Green's function (NEGF) combined with density functional theory (DFT). We demonstrate that with the change of chirality the transport property changes, as predicted by the (n - m) rule. The change of length is also considered. Our results show that the electrical conductance of (10, m) CNTs is larger than that of the (8, m) CNTs, due to larger diameter. Furthermore, we found that the (8, 1) chiral CNT does not follow the (n - m) rule in shorter length and it shows metallic behavior. The cohesive energy, wavefunctions of electronic states, and coupling energy calculation indicate that the devices considered in this study are stable. The transmission spectra, current vs. voltage curves, and transmission eigenchannels provide strong evidence for our findings. Among the (10, m) series, (10, 3) CNT would be the optimal choice for a semiconducting molecular junction device with a significant conductance of 20 µA at 0.8 bias voltage.

Spin-polarized electrical transport properties of organic radicals in presence of zigzag-graphene nanoribbon leads.

The present work delves into the spin-polarized transport property of organic radicals sandwiched between two zigzag-graphene nanoribbon (ZGNR) electrodes by employing density functional theory and nonequilibrium Green's function technique. We demonstrated that the magnetic center(s) of the radical can manipulate the localized edge states of the ZGNR in the scattering region, causing ferromagnetic coupling. Such manipulation of the magnetic edges results in a high spin-filter effect in molecular junctions, and even the antiferromagnetic diradicals serve as nearly perfect spin filters. We have confirmed that this is a general phenomenon of ZGNR by analyzing two antiferromagnetic diradicals and a doublet. The spin-polarized density of states, transmission spectra, and current vs voltage curves of the systems provide strong evidence for our findings. This research strongly suggests that ZGNRs attached with organic radicals could be the perfect building blocks for spintronic materials.

Esophageal Liposarcoma: A rare tumor.

Esophageal liposarcoma is a rare type of tumor. This case report documents the presentation, diagnosis, and management of a 74-year-old male with a medical history including diabetes mellitus, asthma, and hypertension. The patient's primary complaint was dysphagia, accompanied by regurgitation and substantial weight loss over a six-month period. Diagnostic evaluation revealed a sizable esophageal liposarcoma, which was successfully resected through surgery. Follow-up assessments demonstrated the absence of residual mass. Esophageal liposarcomas, though rare, should be considered in patients presenting with dysphagia or chest discomfort. Surgical resection is the mainstay of treatment, with the recommendation for extended postoperative surveillance given the limited available data regarding long-term prognosis.

Laparoscopic management of obturator hernia in the setting of intestinal obstruction: A report of two cases and review of literature.

Owing to its rarity and non-specific clinical features, a diagnosis of obturator hernia is often delayed until the patient presents with intestinal obstruction. Often the diagnosis is made on a Computed Tomography (CT) scan or during exploratory laparotomy. While a laparoscopic approach is well described in an elective scenario, open surgery through a midline laparotomy has been the preferred approach for obturator hernia with intestinal obstruction. However, a few cases of obstructed obturator hernia have been reported that have been managed laparoscopically. We present our experience of two elderly patients who presented with intestinal obstruction. A CT scan helped clinch the diagnosis of obturator hernia as the cause and both were managed laparoscopically.

Spontaneous cutaneous endometriosis in Mons Pubis: review of literature.

Cutaneous endometriosis is not a very often seen condition and is broadly classified as primary (spontaneous) and secondary. While perineal endometriosis arising in a previous scar has been reported, spontaneous cutaneous endometriosis in perineum is extremely rare and only three cases occurring in mons pubis have been reported in literature. We report a case of 34-year-old lady presented with a swelling in pubic region and associated dull aching pain of 1-year duration with no history of cyclical variation of symptoms. Investigations finally concluded a diagnosis of endometriosis and a Complete excision with clear margins. Clinicians should be aware that a spontaneous endometriosis in the perineum can occur and can have atypical presentation with no increase in size or pain during menstruation.

Current practice of antibiotic prophylaxis in elective laparoscopic cholecystectomy among surgeons of the Armed Forces Medical Services of India.

Background: Laparoscopic cholecystectomy (LC) is the most common surgery done in general surgical practice worldwide. Despite clear guidelines recommending against the routine use of antibiotic prophylaxis (ABP) for elective LC by professional entities such as the Scottish Intercollegiate Guidelines Network (SIGN), Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) etc., most surgeons are not convinced about omitting ABP in low-risk LC. Thus, this study aimed at capturing the practice of administering ABP in elective LC among surgeons of Armed Forces Medical Services (AFMS). Methods: This was a survey based on an electronic, cross-sectional, self-completion questionnaire that was designed and disseminated amongst 184 surgeons of the AFMS, online, and the data was collated centrally. Results: 64% of surgeons completed the survey. The majority (85%) of surgeons used ABP routinely in elective LC. In the univariate analysis, only the number of years of surgical experience and the total number of LC done in an entire career, and in the multivariate analysis age group of the surgeon, surgical experience and designation were significant factors for avoiding routine ABP in elective LC. Amongst the surgeons administering ABP, only 30% administered a single dose, 73% chose a single agent and Cefotaxime (57%) was the commonest antibiotic used. Conclusion: This study found that there is a high prevalence of use of antibiotic prophylaxis in elective laparoscopic cholecystectomy amongst the surgeons of the AFMS. There was a wide variation in terms of choice of antibiotics, administering single or multiple doses and as a single agent or combination therapy. Registered with clinical trials registry of India: CTRI/2019/03/018092.

Bannwarth's syndrome and a surgical dilemma: An uncommon zoonosis with a rare presentation.

Lyme's disease also known as Erythema chronicum Migrans, is a multisystem infectious disease caused by the spirochete "Borrelia burgdorferi" which is transmitted by "Ixodes" tick, with both specific and nonspecific manifestations. Nervous system involvement occurs in 10%-15% of untreated patients and typically involves lymphocytic meningitis, cranial neuritis, and/or polyradiculitis. Here, we are reporting an interesting and challenging case of Neuro-Borreliosis in a young officer cadet, meeting the description for Bannwarth's syndrome and presenting initially as a surgical emergency followed by paraparesis. The diagnosis was finally clinched based on clinical profile of Chronic Myeloradiculopathy with focal myositis in the setting of recent outdoor camping, and confirmed by demonstrating high IgG antibody titres in serum and Cerebro spinal fluid (CSF). The officer cadet was treated successfully with a 6 week course of Ceftriaxone and Doxycycline, and went back to full training.

Clinical, genetic, and structural basis of congenital adrenal hyperplasia due to 11ß-hydroxylase deficiency.

Congenital adrenal hyperplasia (CAH), resulting from mutations in CYP11B1, a gene encoding 11ß-hydroxylase, represents a rare autosomal recessive Mendelian disorder of aberrant sex steroid production. Unlike CAH caused by 21-hydroxylase deficiency, the disease is far more common in the Middle East and North Africa, where consanguinity is common often resulting in identical mutations. Clinically, affected female newborns are profoundly virilized (Prader score of 4/5), and both genders display significantly advanced bone ages and are oftentimes hypertensive. We find that 11-deoxycortisol, not frequently measured, is the most robust biochemical marker for diagnosing 11ß-hydroxylase deficiency. Finally, computational modeling of 25 missense mutations of CYP11B1 revealed that specific modifications in the heme-binding (R374W and R448C) or substrate-binding (W116C) site of 11ß-hydroxylase, or alterations in its stability (L299P and G267S), may predict severe disease. Thus, we report clinical, genetic, hormonal, and structural effects of CYP11B1 gene mutations in the largest international cohort of 108 patients with steroid 11ß-hydroxylase deficiency CAH.

Laparoscopic surgery in pancreatic diseases: Pushing the boundaries.

BACKGROUND: Laparoscopic surgery has expanded exponentially in the last two decades but, somehow it is limited in pancreatic surgery by virtue of the pancreas being a friable, retroperitoneal organ with difficult access and adjacent major vessels risking torrential bleed. It is thought to be unforgiving if not handled well. However, improvements in technology and surgeon's expertise have pushed the boundaries of minimal access surgery (MAS) to include pancreas in its domain. We present our series of laparoscopic pancreatic surgery (LPS) with an aim to look at the feasibility and outcomes. METHODS: This is a retrospective review of all LPS done at the Gastrointestinal Surgery (GIS) centre of a tertiary care Armed Forces Hospital over a period of 3 years. RESULTS: A total of 24 LPS were done during this period. The median age of the patients was 46 years (range; 13-81). There were 14 male and 10 female patients. Nine patients had at least one co-morbidity. Three patients underwent laparoscopic lateral pancreaticojejunostomy, 4 distal pancreatectomy, 4 laparoscopic Whipples pancreaticoduodenectomy, 6 laparoscopic pancreatic necrosectomy, 6 laparoscopic cystogastrostomy and 1 roux en y cystojejunostomy. CONCLUSION: LPS can be performed for almost all open pancreatic surgeries and can be done with reasonable outcomes. However, it has a steep learning curve and therefore, a hybrid approach leading to a totally laparoscopic approach may be the way forward.

Early colectomy in steroid-refractory acute severe ulcerative colitis improves operative outcome.

PURPOSE: Up to a third of patients with acute severe ulcerative colitis (ASUC) fail to respond to intensive steroid therapy and eventually require a salvage colectomy. We have previously reported that the mortality of emergency colectomy can be decreased by offering it within the first week of intensive medical therapy. We implemented this policy and report the results of our experience. METHODS: The clinical records of all patients with ASUC who underwent emergency colectomy after failure of medical therapy between January 2005 and July 2015 were extracted from a prospectively maintained database. The data were analysed with regard to duration of intensive medical therapy, timing of surgery, in-hospital mortality and post-operative complications. RESULTS: Eighty-eight patients underwent emergency surgery for ASUC after failed medical therapy. Of these, 75 (85.2%) were operated within 7 days of initiation of intensive medical therapy [n = 51 (58%) were operated < 5 days]. One patient who was operated on day 8 following steroid therapy died postoperatively. The current post-operative mortality of 1.1% (1/88) was significantly lower than the mortality noted in the previously recorded retrospective case series [8/51 (15.6%); p = 0.001]. In addition, the incidence of overall (9/13 vs. 23/75; p = 0.012) and clinically significant (12/75 vs. 6/13; p = 0.022) complications was significantly higher in patients operated after 7 days as compared to those operated within 7 days. CONCLUSION: The policy of early colectomy, within 7 days, in patients with ASUC who fail to respond to intensive steroid-based therapy improves perioperative outcomes with significantly low in-hospital mortality and morbidity.

Mesh erosion into urinary bladder following laparoscopic inguinal hernia repair.

Along with advantages, evolving surgical techniques bring unique complications. A young male developed urinary symptoms a few months after undergoing laparoscopic inguinal hernia repair. On evaluation, mesh erosion into the urinary bladder was found. Removal of mesh with repair of bladder was done. A vesico-cutaneous fistula resulted which was managed with repeat surgery. We review all such cases reported in literature; discuss the etiopathogenesis, presentation, management and possible preventive measures. To the best of our knowledge, this is only the 12th case being reported.

An adolescent with prolapsed omentum per rectum: Spontaneous rectal perforation managed laparoscopically.

Spontaneous rupture of the rectum is a rare occurrence. A total laparoscopic approach to rectal perforation has only occasionally been reported. We report an unusual case of a young boy who developed a spontaneous rupture of the rectum following a trivial fall. A magnetic resonance imaging revealed a tear in the rectum at the peritoneal reflection with the omentum plugging it. He denied any history of rectal instrumentation or abnormal sexual activity. He had no history of constipation or rectal prolapse. The tear was repaired laparoscopically and a covering loop sigmoid colostomy was added. He made an uneventful post-operative recovery. Spontaneous rupture of the rectum can occur in younger age groups and even in the absence of significant trauma. One needs to diligently bring out a history of rectal trauma. Equally important is to rule out any underlying pathological condition. A laparoscopic approach is feasible, especially in early cases.

Expect the unexpected: Endometriosis mimicking a rectal carcinoma in a post-menopausal lady.

Altered bowels habits along with rectal mass in an elderly would point toward a rectal cancer. We report an unusual case of a post-menopausal lady who presented with these complaints. We had difficulties in establishing a pre-operative diagnosis. With a tentative diagnosis of a rectal cancer/gastrointestinal stromal tumor, she underwent a laparoscopic anterior resection. On histopathology, this turned out to be endometriosis. Bowel endometriosis is an uncommon occurrence. That it occurred in a post-menopausal lady was a very unusual finding. We discuss the case, its management, and the relevant literature.

Laparoscopic inguinal hernia repair in the Armed Forces: A 5-year single centre study.

BACKGROUND: Surgery for inguinal hernia continues to evolve. The most recent development in the field of surgery for inguinal hernia is the emergence of laparoscopic inguinal hernia surgery (LIHS) which is challenging the gold standard Lichtenstein's tension free mesh repair. Our centre has the largest series of LIHS from any Armed Forces hospital. The aim of this study was to analyze the short and long term outcomes at our center since its inception. METHODS: Retrospective review of prospectively maintained data base of 501 LIHS done in 434 patients by a single surgeon between April 2008 and October 2013. Preoperative, intraoperative, postoperative and follow-up data was analyzed with emphasis on the recurrence rates and the incidence of inguinodynia. RESULTS: 402 (92.6%) patients had primary hernias and 367 (84.6%) patients had unilateral hernias. Of the 501 repairs, 453 (90.4 %) were done totally extraperitoneal approach and 48 (9.6 %) were done by the transabdominal preperitoneal approach. The mean operative time for unilateral and bilateral repairs was 40.9 ± 11.2 and 76.2 ± 15.0 minutes, respectively. The conversion rate to open surgery was 0.6%. The intraoperative, and early and late postoperative complication rates were 1.7%, 6.2% and 3%, respectively. The incidence of chronic groin pain was 0.7% and the recurrence rate was 1.6%. The median hospital stay was 1 day (1-5 days). CONCLUSION: We, in this series of over 500 repairs have demonstrated that feasibility as well as safety of LIHS at our centre with good short and long term outcomes.

Whipple's pancreaticoduodenectomy: Outcomes at a tertiary care hospital.

BACKGROUND: Pancreaticoduodenectomy is a formidable surgery and was associated with high morbidity and mortality. Though the mortality rates have steadily improved, morbidity continues to be high. There is lack of published data on outcomes following pancreaticoduodenectomy in Armed Forces hospitals. The aim of this study was to analyze the short term outcomes at our center and to compare it with the published literature. METHODS: A retrospective review of prospectively maintained data base was done. Preoperative, intraoperative and postoperative data was analyzed with emphasis on the morbidity and mortality rates. Follow up data was analyzed to look at disease recurrence. RESULTS: Between Jan 2008 and March 2014, 69 patients underwent Whipple's pancreaticoduodenectomy with a median age of 64 years. All had a malignant etiology with periampullary carcinoma being the commonest (42%). Overall, intra-abdominal complications occurred in 46% of patients which included postoperative pancreatic fistula (20%) and delayed gastric emptying (24%). The mortality rate for the whole was 11% which reduced to 8% in the second half of the study. CONCLUSION: The short term outcomes at our center were comparable to those in published literature. The mortality rates showed a decreasing trend with time.

Laparoscopic Pancreaticoduodenectomy With Open Reconstruction: The Buddha's Middle Path.

BACKGROUND: Laparoscopic pancreaticoduodenectomy (LPD) is not universally adopted because of its steep learning curve. Its technical complexity discourages many surgeons. We believe that laparoscopic pancreaticoduodenectomy with open reconstruction (LPOR) has all the benefits of LPD without its drawbacks and combines the ease of open surgery with the benefits of minimal access surgery. We assessed the feasibility and safety of LPOR and compared it with open pancreaticoduodenectomy (OPD), with the objectives being perioperative and short-term clinical/oncologic outcomes. METHODS: Retrospective review of prospectively maintained database; study period from January 2013 to December 2019. Till 2015, we did only OPD. In 2016, we started with LPD but soon switched to LPOR. The resection part was done laparoscopically and the reconstruction part was done through a 8-cm mini-laparotomy. RESULTS: We did 19 OPDs and 15 LPORs. Demographic data of the 2 groups were comparable. The duration of surgery was significantly longer in the LPOR group (360 vs. 410 min; P=0.01), whereas the blood loss and hospital stay were longer in the OPD group (520 vs. 360 mL; P=0.03 and 13 vs. 11 d; P=0.08, respectively). Clinically significant complication rates, including delayed gastric emptying and postoperative pancreatic fistulas, were not different in either group. No patients in the LPOR group had wound-related/pulmonary complications. Lymph node yield was similar in both groups (20 vs. 22) and we had 100% R0 resections. CONCLUSIONS: LPOR was better than OPD in terms of short-term outcomes and was not inferior to OPD in terms of complications/oncologic outcomes.

Single port laparoscopic repair of paediatric inguinal hernias: Our experience at a secondary care centre.

BACKGROUND: Congenital inguinal hernias are a common paediatric surgical problem and herniotomy through a groin incision is the gold standard. Over the last 2 decades minimally invasive surgery (MIS) has challenged this conventional surgery. Over a period, MIS techniques have evolved to making it more minimally invasive - from 3 to 2 and now single port technique. All studies using single port technique are from tertiary care centres. We used a modification of the technique described by Ozgediz et al. and reviewed the clinical outcome of this novel procedure and put forth our experience at a secondary level hospital. MATERIALS AND METHODS: Prospective review of 37 hernias in 31 children (29 male and 2 female) (8 months - 13 years) performed laparoscopically by a single surgeon at a single centre between September 2007 and June 2010. Under laparoscopic guidance, the internal ring was encircled extraperitoneally using a 2-0 non-absorbable suture and knotted extraperitoneally. Data analyzed included operating time, ease of procedure, occult patent processus vaginalis (PPV), complications, and cosmesis. RESULTS: Sixteen right (52%), 14 left (45%) and 1 bilateral hernia (3%) were repaired. Five unilateral hernias (16.66%), all left, had a contralateral PPV that was repaired (P = 0.033). Mean operative time for a unilateral and bilateral repair were 13.20 (8-25) and 20.66 min (17 -27 min) respectively. Only one of the repairs (2.7%) recurred and another had a post operative hydrocoele (2.7%). One case (2.7%) needed an additional port placement due to inability to reduce the contents of hernia completely. There were no stitch abscess/granulomas, obvious spermatic cord injuries, testicular atrophy, or nerve injuries. CONCLUSION: Single port laparoscopic inguinal hernia repair can be safely done in the paediatric population. It permits extension of benefits of minimal access surgery to patients being managed at secondary level hospitals with limited resources. The advantage of minimal instrumentation and avoidance of intracorporeal knotting makes it a feasible technique for a secondary care centre.

Abdominal Crunch Syndrome Creates a -Diagnostic Challenge in Treating a Pilot with Acute Upper -Abdominal Pain.

BACKGROUND: A diagnosis in acute abdomen may remain elusive especially when the cause is rare. We report this interesting case of a fighter pilot presenting with acute abdominal pain. The case posed significant challenges in reaching the correct diagnosis of abdominal crunch syndrome. The syndrome is rare with only seven reports in the literature so far. To the best of our knowledge, this is the first ever report of this condition in an aircrew.CASE REPORT: A 37-yr-old pilot presented with severe upper abdominal pain and sweating. During examination, he developed bradycardia and was admitted with a presumptive diagnosis of acute coronary syndrome. Investigations revealed no myocardial ischemia on ECG, transaminitis, raised CPK, CKMB, and LDH. A CECT scan of chest and abdomen was normal. A GI surgery consult was sought where we connected the transaminitis and raised CPK and considered the possibility of rhabdomyolysis. On specific inquiry, the aviator gave history of unaccustomed exercise with a vigorous session of abdominal crunches a day prior. Thus, a diagnosis of abdominal crunch syndrome was concluded.DISCUSSION: The aviator did not associate his vigorous exercise with the occurrence of pain and, therefore, did not mention it. It would have avoided unnecessary investigations and delay in treatment. From the aeromedical safety aspect, had the aviator flown on the day he developed pain, there was a possibility of developing severe pain exacerbated by the G force and G suit and sudden in-flight incapacitation. From the perspective of the aircrew, it is advisable that they avoid sudden, unaccustomed exercise.Kumar A, Kaistha S. Abdominal crunch syndrome creates a diagnostic challenge in treating a pilot with acute upper abdominal pain. Aerosp Med Hum Perform. 2023; 94(2):86-89.

A Case Report of Paralysis and Respiratory Difficulty in a Patient With a Recent History of Complicated Pregnancy - An Uncommon Expression of Distal Renal Tubular Acidosis.

Renal tubular acidosis type 1 (RTA-1) is a disorder where kidneys are unable to acidify urine, which ultimately results in normal anion gap metabolic acidosis. Its initial presentations and subsequent clinical manifestations can vary depending on the underlying cause and severity of the disease. We report a case of a 26-year-old female with a recent history of complicated pregnancy. She presented to a tertiary care hospital with quadriplegia and shortness of breath and required ventilator support. The extensive workup revealed that the patient had RTA-1 in association with Sjögren's syndrome. There are only a few cases of RTA-1 reported where the diagnosis was made during the pregnancy. By reporting this case of RTA-1 with rare initial clinical presentation and a recent complicated pregnancy, we propose that further research studies should be carried out in this area to explore a possible statistically significant association between pregnancy (and its complications) and RTA-1 exacerbation.