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The production of hydrogen-based dense energy carriers (DECs) has been proposed as a combined solution for the storage and dispatch of power generated through intermittent renewables. Frameworks that model and optimize the production, storage, and dispatch of generated energy are important for data-driven decision making in the energy systems space. The proposed multiperiod framework considers the evolution of technology costs under different levels of promotion through research and targeted policies, using the year 2021 as a baseline. Furthermore, carbon credits are included as proposed by the 45Q tax amendment for the capture, sequestration, and utilization of carbon. The implementation of the mixed-integer linear programming (MILP) framework is illustrated through computational case studies to meet set hydrogen demands. The trade-offs between different technology pathways and contributions to system expenditure are elucidated, and promising configurations and technology niches are identified. It is found that while carbon credits can subsidize carbon capture, utilization, and sequestration (CCUS) pathways, substantial reductions in the cost of novel processes are needed to compete with extant technology pathways. Further, research and policy push can reduce the levelized cost of hydrogen (LCOH) by upwards of 2 USD/kg. [ABSTRACT FROM AUTHOR]

In this work, we present a generic multi‐period integrated infrastructure planning and operational scheduling approach for developing energy systems. The methodology is applicable to energy systems with multiple resources, locations, processing pathways, and planning periods in which infrastructure decisions can be carried out. The framework incorporates a graph based approach to mode based scheduling, in which the mode transitions are mapped to a directed graph. We illustrate the applicability and effectiveness of the overall framework through the use of a case study examining the long‐term development of a multi‐site energy‐intensive hydrogen based energy system in Texas. In the case study, we find that developing the energy system over the course of its operational life as opposed to the beginning of its operational life reduces its capital and operational cost by over 20%. [ABSTRACT FROM AUTHOR]

Sinistral portal hypertension is a clinical syndrome of gastric variceal hemorrhage in the setting of splenic vein thrombosis due to a primary pancreatic pathology. The distinguishing features from other forms of portal hypertension are preserved liver function and a patent extrahepatic portal vein. The important causes include acute and chronic pancreatitis, pancreatic pseudocysts and pancreatic carcinomas. Benign pancreatic neoplasms only rarely cause sinistral portal hypertension. Splenic vein thrombosis complicates 7-20% of patients having pancreatitis or a pancreatic pseudocyst; however, bleeding occurs in only approximately 5% of patients. The diagnosis of sinistral portal hypertension is achieved by a combination of gastroscopy, liver function tests, ultrasound examination (with Doppler) and/or contrast-enhanced CT scan of the abdomen. A mere demonstration of sinistral portal hypertension does not warrant intervention. An expectant management is justifiable in asymptomatic patients with pancreatitis. However, concomitant splenectomy may be considered in patients undergoing operative treatment of symptomatic chronic pancreatitis if sinistral portal hypertension and gastroesophageal varices are present. In patients presenting with gastric variceal hemorrhage, splenectomy (with treatment for the primary pancreatic pathology, e.g. distal pancreatectomy) is curative with excellent long term results.

Pancreatic pseudocysts (PPs) comprise more than 80% of the cystic lesions of the pancreas and cause complications in 7-25% of patients with pancreatitis or pancreatic trauma. The first step in the management of PPs is to exclude a cystic tumor. A history of pancreatitis, no septation, solid components or mural calcification on CT scan and high amylase content at aspiration favor a diagnosis of PP. Endoscopic ultrasound (EUS)-guided FNAC is a valuable diagnostic aid. Intervention is indicated for PPs which are symptomatic, in a phase of growth, complicated (infected, hemorrhage, biliary or bowel obstruction) or in those occurring together with chronic pancreatitis and when malignancy cannot be unequivocally excluded. The current options include percutaneous catheter drainage, endoscopy and surgery. The choice depends on the mode of presentation, the cystic morphology and available technical expertise. Percutaneous catheter drainage is recommended as a temporizing measure in poor surgical candidates with immature, complicated or infected PPs. The limitations include secondary infection and pancreatic fistula in 10-20% of patients which increase complications following eventual definitive surgery. Endoscopic therapy for PPs including cystic-enteric drainage (and transpapillary drainage), is an option for PPs which bulge into the enteric lumen which have a wall thickness of less than 1 cm and the absence of major vascular structures on EUS in the proposed tract or those which communicate with the pancreatic duct above a stricture. Surgical internal drainage remains the gold standard and is the procedure of choice for cysts which are symptomatic or complicated or those having a mature wall,. Being more versatile, a cystojejunostomy is preferred for giant pseudocysts (>15 cm) which are predominantly inframesocolic or are in an unusual location. In PPs with coexisting chronic pancreatitis and a dilated pancreatic duct, duct drainage procedures (such as longitudinal pancreaticojejunostomy) should be preferred to a cyst drainage procedure.

Gastro-intestinal haemorrhage is not uncommon and is manifested as haematemesis, melaena or haematochezia. The first step is to resuscitate the patient if necessary and then proceed to make a diagnosis as well as divide patients into high and low-risk groups after taking a good history and performing a physical examination especially to detect the presence of an enlarged spleen. Then one should proceed with an endoscopy and other investigations chosen carefully for their usefulness. Control of bleeding is then tailored to the diagnosis and is usually with drugs, endoscopy, angio-embolisation and surgery in that order. The mortality rate for upper GI bleeding varies from 10 to 30% depending on the proportion of patients with variceal haemorrhage included. For lower GI bleeding mortality is in the region of 20% and for obscure GI bleeding outpatient mortality is 12%. The main points to remember are that the management of these patients in India should be different from those described in Western textbooks and suited to their specific needs and the facilities available locally. However, in spite of the widespread lack of complex diagnostic techniques and a shortage of blood for transfusion we believe that by adopting an aggressive step-by-step approach tailored to our own environment we will be able to save most of our patients who are usually young and have few comorbid conditions.

Introduction: Colonic diverticulosis was previously uncommon in India but its incidence seems to have increased recently. Patients with the disease in developing countries are also underdiagnosed and are therefore more likely to present with complications needing operation. However there is a paucity of surgical data on the condition., Method: Between August 1996 and February 2005 we operated on 32 patients (28 males, 4 females mean age 60 years) with colonic diverticulosis and analysed their characteristics from a prospective database. We here with describe our experience., Results: Operations for diverticular disease constituted 3% of all the colorectal operations we performed. The diverticula were in the sigmoid colon in 28 (88%) and also in the descending colon in 4 (12%). Twenty-four patients were symptomatic. Twenty-two patients were diagnosed before surgery, 8 at operation and the rest from resected specimens. Emergency operations were performed in 23 and elective procedures in 9 patients. Ten patients were operated on for perforation and abscess, 8 for obstruction, 8 for colovesical fistula, 3 for peritonitis and 3 for haemorrhage. Emergency procedures were performed in 2 stages (resection plus a proximal diversion) in 20; unless done for bleeding in a stable patient where a primary anastomosis was done. One patient who had had an emergency procedure died of sepsis and ketoacidosis in the post-operative period. The 8 patients with colovesical fistulae were all males, had only sigmoid involvement and had had symptoms for a longer duration than the 24 without fistulae., Conclusions: Although operations for colonic diverticulosis still form a small proportion of the total number of colorectal operations, the diagnosis is often delayed till complications ensue and thus patients usually require emergency procedures. Males with long standing symptoms and sigmoid diverticula may develop colovesical fistulae.