K. Rajan

Single-stage laparoscopic common bile duct exploration and cholecystectomy versus two-stage endoscopic stone extraction followed by laparoscopic cholecystectomy for patients with concomitant gallbladder stones and common bile duct stones: a randomized controlled trial.

BackgroundThe ideal method for managing concomitant gallbladder stones and common bile duct (CBD) stones is debatable. The currently preferred method is two-stage endoscopic stone extraction followed by laparoscopic cholecystectomy (LC). This prospective randomized trial compared the success and cost effectiveness of single- and two-stage management of patients with concomitant gallbladder and CBD stones.MethodsConsecutive patients with concomitant gallbladder and CBD stones were randomized to either single-stage laparoscopic CBD exploration and cholecystectomy (group 1) or endoscopic retrograde cholangiopancreatography (ERCP) for endoscopic extraction of CBD stones followed by LC (group 2). Success was defined as complete clearance of CBD and cholecystectomy by the intended method. Cost effectiveness was measured using the incremental cost-effectiveness ratio. Intention-to-treat analysis was performed to compare outcomes.ResultsFrom February 2009 to October 2012, 168 patients were randomized: 84 to the single-stage procedure (group 1) and 84 to the two-stage procedure (group 2). Both groups were matched with regard to demographic and clinical parameters. The success rates of laparoscopic CBD exploration and ERCP for clearance of CBD were similar (91.7 vs. 88.1xa0%). The overall success rate also was comparable: 88.1xa0% in group 1 and 79.8xa0% in group 2 (pxa0=xa00.20). Direct choledochotomy was performed in 83 of the 84 patients. The mean operative time was significantly longer in group 1 (135.7xa0±xa036.6 vs. 72.4xa0±xa027.6xa0min; pxa0≤xa00.001), but the overall hospital stay was significantly shorter (4.6xa0±xa02.4 vs. 5.3xa0±xa06.2xa0days; pxa0=xa00.03). Group 2 had a significantly greater number of procedures per patient (pxa0<xa00.001) and a higher cost (pxa0=xa00.002). The two groups did not differ significantly in terms of postoperative wound infection rates or major complications.ConclusionsSingle- and two-stage management for uncomplicated concomitant gallbladder and CBD stones had similar success and complication rates, but the single-stage strategy was better in terms of shorter hospital stay, need for fewer procedures, and cost effectiveness.

Laparoscopic Suturing Skills Acquisition: A Comparison Between Laparoscopy-Exposed and Laparoscopy-Naive Surgeons

This study suggests that training improves laparoscopic suturing skills in experienced as well as inexperienced laparoscopic surgeons.

A Prospective Randomized Controlled Blinded Study to Evaluate the Effect of Short-Term Focused Training Program in Laparoscopy on Operating Room Performance of Surgery Residents (CTRI /2012/11/003113)

INTRODUCTIONnLaparoscopic surgery requires certain specific skills. There have been several attempts to minimize the learning curve with training outside the operation room. Although simulators have been well validated as tools to teach technical skills, their integration into comprehensive curricula is lacking. Several randomized controlled trials and systematic reviews have demonstrated that the technical skills learned on these simulators transfer to the operating room. Currently, however, the integration of these simulated models into formal residency training curricula is lacking. In our institute, we have adopted the Tuebingen Trainer devised by Professor GF Buess from Germany. The purpose of this study was to evaluate the training of surgical residents on an ex vivo phantom model for basic laparoscopic skill acquisition and its transferability to the OR performance.nnnMATERIALS AND METHODSnSeventeen general surgery residents were randomized into 2 groups: Laparoscopic Training Group (n = 9, Group A) and Standard Training Group (n = 8, Group B). Group A underwent training in the Minimally Invasive Surgery Training Centre on the porcine phantom model and did 10 laparoscopic cholecystectomies, whereas Group B did not undergo training in the Minimally Invasive Surgery Training Centre. All the participants performed a laparoscopic cholecystectomy in the operation theater in the presence of a consultant who was blinded to the training status of the participants. The performance of the residents in both groups in the operation theater was assessed using GOALS criteria, surgical performance assessment parameters, task-specific checklists, and visual analog scale for gallbladder perforation difficulty and overall competence.nnnRESULTSnThe Laparoscopic Training Group had better performance than the Standard Training Group regarding operation time, GOALS criteria, and Task-specific checklists. Although the surgical performance assessments, i.e. cystic duct and artery identification scores, gallbladder perforation scores, and liver injury scores, were better in the Laparoscopic Training Groups, they were not statistically significant. The overall difficulty of the surgery was comparable in both the groups. The Laparoscopic Training Group exhibited significant overall competence on visual analog scale scores.nnnCONCLUSIONnOur study has clearly shown that training on the Tuebingen Trainer with integrated porcine organs results in a statistically significant improvement in the operating room performance of surgical residents as compared with the nontrained residents, thereby indicating a transfer of skills from training to the operating room.

Solar tracking system – a review

Abstract The generation of power from the reduction of fossil fuels is the biggest challenge for the next half century. The idea of converting solar energy into electrical energy using photovoltaic panels holds its place in the front row compared to other renewable sources. But the continuous change in the relative angle of the sun with reference to the earth reduces the watts delivered by solar panel. In this context solar tracking system is the best alternative to increase the efficiency of the photovoltaic panel. Solar trackers move the payload towards the sun throughout the day. In this paper different types of tracking systems are reviewed and their pros and cons are discussed in detail. The results presented in this review confirm that the azimuth and altitude dual axis tracking system is more efficient compared to other tracking systems. However in cost and flexibility point of view single axis tracking system is more feasible than dual axis tracking system.

Prospective Case–Control Study to Evaluate the Role of Glutathione S Transferases (GSTT1 and GSTM1) Gene Deletion in Breast Carcinoma and Its Prognostic Significance

Breast cancer is the most common cause of cancer death in women with the incidence rising in young women. GST gene polymorphisms are significant because of their role in the detoxification of both environmental carcinogens and also cytotoxic drugs used in therapy for breast cancer. The present study has been designed to identify the role of polymorphisms in GSTT1 and GSTM1 genes in the risk of development of breast cancer, in the prognostication of breast cancer, and in the prediction of response towards chemotherapy. Ninety-nine patients with breast cancer and 100 healthy controls with no history of cancer were taken from blood donors after informed consent. Epidemiological and clinical data was collected from participants and 5xa0ml of peripheral venous blood was collected for genotype analysis. Null genotype of GSTT1 was detected in 51.04xa0% of the controls in comparison to 20.2xa0% of patients with carcinoma breast, which was found to be statistically significant (OR 4.18; 95xa0% CI 2.01–8.75; Pu2009=u20090.0001). GSTM1 gene deletion was also significantly more common among controls (60xa0%) than in patients with breast cancer (33xa0%) (OR 4.57; 95xa0% CI 2.20–9.51; Pu2009=u20090.0001). Tumors more than 5xa0cm in size had greater tendency for GSTM1 gene expression (P valueu2009=u20090.019), but other clinicopathological parameters did not show any correlation. GSTT1 and GSTM1 genes status did not show any association with response to chemotherapy. The results indicated the null genotype of both GSTT1 and GSTM1 to be protective for the development of carcinoma breast. None of the known etiological factors have any correlation with GSTT1 and GSTM1 gene deletion. Patients with small tumor size expressed GSTM1 gene deletion. Other tumor characteristics and clinicopathological parameters did not have any correlation with gene deletion.

Factors Affecting Short-Term and Long-Term Outcomes After Bilioenteric Reconstruction for Post-cholecystectomy Bile Duct Injury: Experience at a Tertiary Care Centre

Bile duct injury following cholecystectomy is an iatrogenic catastrophe associated with significant perioperative morbidity, reduced long-term survival and quality of life. There has been little literature on the long-term outcomes after surgical reconstruction and factors affecting it. The aim of this study was to study factors affecting long-term outcomes following surgical repair of iatrogenic bile duct injury being referred to a tertiary care centre. Between January 2005 to December 2011, 138 patients with bile duct injury were treated in a single surgical unit in a tertiary care referral hospital. Preoperative details were recorded. After initial resuscitation, any intra-abdominal collection was drained and an imaging of biliary anatomy was done. Once the general condition of the patient improved, patients were taken up for a side-to-side extended left duct hepaticojejunostomy. The post-operative outcomes were recorded and a hepatobiliary iminodiacetic acid scan and liver function tests were done, and then the patients were followed up at regular intervals. Clinical outcome was evaluated according to clinical grades described by Terblanche and Worthley (Surgery 108:828–834, 1990). The variables were compared using chi-square, unpaired Student’s t test and Fisher’s exact test. A two-tailed p value of <0.05 was considered significant. One hundred thirty-eight patients, 106 (76.8xa0%) females and 32 (23.2xa0%) males with an age range of 20–63xa0years (median 40.8u2009±u2009SD) with bile duct injury following open or laparoscopic cholecystectomy, were operated during this period. Majority of the patients [83 (60.1xa0%)] had a delayed presentation of more than 3xa0months. Based on imaging, Strasburg type E1 was seen in 17 (12.5xa0%), type E2 in 30 (21.7xa0%), type E3 in 85 (61.5xa0%) and type E4 in 6 (4.3xa0%). On multivariate analysis, only level of injury, longer duration of referral and associated vascular injury were independently associated with an overall poor long-term outcome. This study demonstrates level of injury at or above the confluence; associated vascular injury and delay in referral were associated with poorer outcomes in long-term follow-up; however, almost all patients had excellent outcome in long-term follow-up.

Performance and Emission Characteristics of a Di Diesel Engine Fuelled with Cashew Nut Shell Oil (CNSO)-Diesel Blends with Diethyl Ether as Additive

Cashew nut shell oil (CNSO) is potential alternative fuel for diesel engine. Its drawback is incomplete combustion and low brake thermal efficiency (BTE) due to high viscosity. To overcome this problem the CNSO was blended with diethyl ether (DEE) which is less viscous and burns easily. The influence of blends on CO, NOx and smoke emission is investigated by emission tests. The fuel containing 20% CNSO and 80% diesel fuel (B20), 95% B20 and 5% DEE by volume (B20D5), 90% B20 and 10%DEE by volume (B20D10) 85% and B20 and 15% DEE by volume (B20D15) are tested. Initially the experiment was conducted with different blends of CNSO-diesel blends like 10%, 20%, & 30% by volume basis in a diesel engine.The aim for the research of alternative fuel is to replace the sufficient amount of diesel fuel without affecting the existing engine performances. Increasing CNSO diesel blends performances reduces marginally. B10 shows more closer performances to diesel fuel, but replacement of 10% only diesel is not much. Using B30 and higher blends gives poor result. Hence it was decided to be B20. In the second stage B20 as a base fuel and it is blended with DEE 5%, 10% & 15% by volume basis at different load conditions. The result shows that B20D15 has BTE 26.50% which is very close to the base diesel fuel. The B20D15 emits 1200 PPM of NOx while diesel emits 1195 PPM but B20 emits 1450 PPM of Nox. Carbon monoxide (CO) emission also reduces for different blends of DEE. The smoke emission is 3.96, 3.38, 3.15 FSN of B20, B20 D15 and diesel respectively.

Green fuel utilization for diesel engine, combustion and emission analysis fuelled with CNSO diesel blends with Diethyl ether as additive

The experimental investigation is conducted to evaluate the effects by using Diethyl ether (DEE) as an additive. The Cashew Nut Shell Oil diesel blends (CDB) are tested in a 4-stroke single cylinder DI unmodified diesel engine, rated power is 4.4 kW at a speed of 1500 rpm. The effect of combustion analysis of test fuels on net heat release rate, cylinder pressure, engine power, BSFC, BTE, EGT were observed by the performance tests. The combustion and emission characteristics of a diesel engine with an additive of high cetane number is utilized with CDB and thus investigated. The influence of blends on CO, CO2, HC, NOx and smoke opacity is investigated by emission tests. Initially, the experiment was conducted with different blends of CDB diesel blends like 10%, 20%, & 30% by volume basis in a diesel engine. Among this blends B20 shows reasonable result and heat dissipation rate at full load conditions. The BTE of B20 is 27.52% whereas base diesel fuel is 29.73%. Addition of the DEE by 5%, 10% and 15% by volume basis with B20 which is a base fuel has resulted with improved estimates. The result shows that at full load conditions BTE of B20D10 is 28.96% which is close to the base fuel i.e. B20. The emissions like CO2 shows reducing trends while HC emission rises with increase in CNSO blends. The HC in diesel corresponds to 30ppm and in B20 it is 34ppm, but addition of DEE shows a decreasing trend as in B20D5 has 29ppm and B20D15 has 23ppm respectively. NOx also shows increasing trends with CNSO blend, after addition of DEE it shows declining trend. The NOx for diesel, B20, B30, B20D5, B20D10 and B20D15 emits 1195, 1450, 1511, 1327, 1373 and 1200ppm respectively. The smoke emission is 3.96, 3.38, 3.15 FSN of B20, B20D15 and diesel respectively.

Experimental Evaluation of Compression Ignition Engine Fueled with Cashew Nut Shell Liquid Diesel Blend with the Effect of Various Injection Pressures

This paper investigates the performance and emission characteristics of 20% cashew nut shell liquid (CNSL)-diesel blend (B20) in a direct injection diesel engine. The cashew nut shell liquid was prepared by pyrolysis method. The test was conducted with various nozzle opening pressures like 200 bar, 225 bar and 250 bar at different loads between no load to full load. The results showed that the brake thermal efficiency was increased by 2.54% for B20 with 225 bar at full load. The CO and smoke emissions were decreased by 50% and 14% respectively and the NOx emission were decreased slightly with 225 bar injection pressure compared with 200 bar and 250 bar at full load. On the whole, it is concluded that the B20 CNSL blend can be effectively used as a fuel for diesel engine with 225 bar injection pressure without any modifications.

Preperation and Characterization Study of Phase Change Materials for Thermal Energy Storage Applications

Thermal Energy Storage using phase change materials (PCM) has become an interesting area of energy research because of its high energy storage density, isothermal nature of storage process and small volume changes. In the present work paraffin wax (PW) and Palmitic acids(PA) are chosen as phase change materials and mixed in different proportions(40-60% PW-PA, 50-50% PW-PA and 60-40% PW-PA) to prepare eutectic PCMs. And also paraffin is combined with Copper oxide nano powder to prepare composite PCM. Differential Scanning Calorimetric (DSC) Tests have been conducted to find the latent heat capacity of the above combination of PCMs. The results showed that 40-60%PW-PA eutectic mixture is effective in increasing the latent heat of fusion compared to the other combinations.