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BACKGROUND: Whether the benefits of the robotic platform in bariatric surgery translate into superior surgical outcomes remains unclear. The aim of this retrospective study was to establish the 'best possible' outcomes for robotic bariatric surgery and compare them with the established laparoscopic benchmarks. METHODS: Benchmark cut-offs were established for consecutive primary robotic bariatric surgery patients of 17 centres across four continents (13 expert centres and 4 learning phase centres) using the 75th percentile of the median outcome values until 90 days after surgery. The benchmark patients had no previous laparotomy, diabetes, sleep apnoea, cardiopathy, renal insufficiency, inflammatory bowel disease, immunosuppression, history of thromboembolic events, BMI greater than 50â kg/m2, or age greater than 65 years. RESULTS: A total of 9097 patients were included, who were mainly female (75.5%) and who had a mean(s.d.) age of 44.7(11.5) years and a mean(s.d.) baseline BMI of 44.6(7.7) kg/m2. In expert centres, 13.74% of the 3020 patients who underwent primary robotic Roux-en-Y gastric bypass and 5.9% of the 4078 patients who underwent primary robotic sleeve gastrectomy presented with greater than or equal to one complication within 90 postoperative days. No patient died and 1.1% of patients had adverse events related to the robotic platform. When compared with laparoscopic benchmarks, robotic Roux-en-Y gastric bypass had lower benchmark cut-offs for hospital stay, postoperative bleeding, and marginal ulceration, but the duration of the operation was 42â min longer. For most surgical outcomes, robotic sleeve gastrectomy outperformed laparoscopic sleeve gastrectomy with a comparable duration of the operation. In robotic learning phase centres, outcomes were within the established benchmarks only for low-risk robotic Roux-en-Y gastric bypass. CONCLUSION: The newly established benchmarks suggest that robotic bariatric surgery may enhance surgical safety compared with laparoscopic bariatric surgery; however, the duration of the operation for robotic Roux-en-Y gastric bypass is longer.
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Cirurgia Bariátrica , Derivação Gástrica , Laparoscopia , Obesidade Mórbida , Procedimentos Cirúrgicos Robóticos , Humanos , Feminino , Idoso , Adulto , Masculino , Derivação Gástrica/efeitos adversos , Obesidade Mórbida/cirurgia , Benchmarking , Estudos Retrospectivos , Cirurgia Bariátrica/efeitos adversos , Laparoscopia/efeitos adversos , Gastrectomia/efeitos adversos , Resultado do TratamentoRESUMO
Curcumin is a key constituent of turmeric with a variety of biological activities. From a chemical point of view, curcumin contains different functional groups that can undergo multiple transformations such as Michael addition, cycloaddition, click reaction, polymerisation, etc. Among these, Michael-type reactions under benign conditions constitute a captivating domain of curcumin's reactivity. To the best of our knowledge, no review focusing on the Michael donor-acceptor reactivity of curcumins has been published to date. Herein, we have compiled the chemistry of curcumins with respect to their chemical synthesis, biosynthesis, and involvement in chemical transformations, especially in Michael additions with advances in mechanistic aspects and understanding.
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Detecting z-drugs, a sedative-hypnotic medication, is also misused for criminal activities. Therefore, the analysis of urine samples is crucial for clinical and forensic purposes. We conducted a study where we developed, validated, and compared an analytical method for simultaneously detecting z-drugs in urine samples. Our approach uses the QuEChERS method for sample preparation, combined with liquid chromatography (LC) and gas chromatography (GC) coupled with tandem mass spectrometry (MS/MS). We optimized the QuEChERS method to effectively extract z-drugs from urine samples while minimizing matrix effects and achieving high recovery rates. After extraction, we split the samples into two parts for analysis using LC-MS/MS and GC-MS/MS. We validated our methods, and the results showed good linearity over a broad concentration range (1-200 ng/mL) for each z-drug. The limits of detection and quantification were within clinically relevant ranges, ensuring sensitivity for detecting z-drugs in urine samples. We compared the two chromatographic techniques by analyzing a set of urine samples spiked with known concentrations of z-drugs using both LC-MS/MS and GC-MS/MS methods and then applied to the real samples. The results were statistically analyzed to assess any significant differences in accuracy and precision above 95 %, and both methods offered reliable and consistent results with the samples as well. In conclusion, our analytical method coupled with both LC-MS/MS and GC-MS/MS using the QuEChERS approach provides a comprehensive and robust solution for the simultaneous detection of z-drugs in urine samples. The choice between the two chromatographic techniques can be based on the specific z-drugs of interest and the required analytical performance. This method holds promise for applications in clinical toxicology, forensic analysis, and monitoring z-drug usage.
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Idiopathic chylopericardium (CP) in the pediatric population is a rare entity with very few reported cases and is characterized by the accumulation of chyle in the pericardial cavity. There are no guidelines for the management of this rare entity. The present study reports a case of idiopathic CP in an infant and our experience of managing it by pericardial window creation using VATS and a multidisciplinary approach providing the optimum care for the child.
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A cascade inter-intramolecular double Michael strategy for the synthesis of highly functionalized cyclohexanones from curcumins and arylidenemalonates is reported. This strategy works in the presence of aqueous KOH using TBAB as a suitable phase transfer catalyst at room temperature. The functionalized cyclohexanones are formed as major products in moderate to excellent yields with complete diastereoselectivity in most cases. A triple Michael adduct, tetrahydrochromen-4-one, is also formed as a side product in a few cases with excellent diastereoselectivity.
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Photoplethysmography (PPG) is used to measure blood volume changes in the microvascular bed of tissue. Information about these changes along time can be used for estimation of various physiological parameters, such as heart rate variability, arterial stiffness, and blood pressure, to name a few. As a result, PPG has become a popular biological modality and is widely used in wearable health devices. However, accurate measurement of various physiological parameters requires good-quality PPG signals. Therefore, various signal quality indexes (SQIs) for PPG signals have been proposed. These metrics have usually been based on statistical, frequency, and/or template analyses. The modulation spectrogram representation, however, captures the second-order periodicities of a signal and has been shown to provide useful quality cues for electrocardiograms and speech signals. In this work, we propose a new PPG quality metric based on properties of the modulation spectrum. The proposed metric is tested using data collected from subjects while they performed various activity tasks contaminating the PPG signals. Experiments on this multi-wavelength PPG dataset show the combination of proposed and benchmark measures significantly outperforming several benchmark SQIs with improvements of 21.3% BACC (balanced accuracy) for green, 21.6% BACC for red, and 19.0% BACC for infrared wavelengths, respectively, for PPG quality detection tasks. The proposed metrics also generalize for cross-wavelength PPG quality detection tasks.
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Fotopletismografia , Dispositivos Eletrônicos Vestíveis , Humanos , Frequência Cardíaca/fisiologia , Pressão Sanguínea , Volume Sanguíneo , Processamento de Sinais Assistido por Computador , AlgoritmosRESUMO
In the past, curcumin was the go-to medication for diabetes, but recent studies have shown that tetrahydrocurcumin is more effective. The problem is that it's not very soluble in water or very bioavailable. So, our research aims to increase the bioavailability and anti-diabetic efficacy of tetrahydrocurcumin in streptozotocin-induced diabetic rats by synthesizing tetrahydrocurcumin-loaded solid lipid nanoparticles. Box Behnken Design was employed for the optimization of tetrahydrocurcumin-loaded solid lipid nanoparticles (THC-SLNs). The optimal formulation was determined by doing an ANOVA to examine the relationship between the independent variables (drug-to-lipid ratio, surfactant concentration, and co-surfactant concentration) and the dependent variables (particle size, percent entrapment efficiency, and PDI). Particle size, PDI, and entrapment efficiency all showed statistical significance based on F-values and p-values. The optimized batch was prepared using a drug-to-lipid ratio (1:4.16), 1.21% concentration of surfactant, and 0.4775% co-surfactant (observed with a particle size of 147.1 nm, 83.58 ± 0.838 % entrapment efficiency, and 0.265 PDI, and the values were found very close with the predicted ones. As the THC peak vanishes from the DSC thermogram of the improved formulation, this indicates that the drug has been transformed from its crystalline form into its amorphous state. TEM analysis of optimized formulation demonstrated mono-dispersed particles with an average particle size of 145 nm which are closely related to zetasizer's results. In-vitro release study of optimized formulation demonstrated burst release followed by sustained release up to 71.04% throughout 24 hrs. Increased bioavailability of the adjusted THC-SLN was found in an in vivo pharmacokinetics research with 9.47 folds higher AUC(0-t) compared to plain THC-suspension. Additionally, pharmacodynamic experiments of optimized formulation demonstrated a marked decrease in blood glucose level to 63.7% and increased body weight from 195.8 ± 7.223 to 231.2 ± 7.653 on the 28th day of the study and showed a better anti-diabetic effect than plain drug suspension. Results of stability studies revealed that formulation can be stored for longer periods at room temperature. Tetrahydrocurcumin can be effectively administered by SLN for the treatment of diabetes.
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[This corrects the article DOI: 10.1016/j.jsps.2023.05.002.].
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Uterine fibroids (UF), most prevalent gynecological disorder, require surgery when symptomatic. It is estimated that between 25 and 35 percent of women wait until the symptoms have worsened like extended heavy menstrual bleeding and severe pelvic pain. These UF may be reduced in size through various methods such as medical or surgical intervention. Progesterone (prog) is a crucial hormone that restores the endometrium and controls uterine function. In the current study, 28 plant-based molecules are identified from previous literature and docked onto the prog receptors with 1E3K and 2OVH. Tanshinone-I has shown the best docking score against both proteins. The synthetic prog inhibitor Norethindrone Acetate is used as a standard to evaluate the docking outcomes. The best compound, tanshinone-I, was analyzed using molecular modeling and DFT. The RMSD for the 1E3K protein-ligand complex ranged from 0.10 to 0.42 Å, with an average of 0.21 Å and a standard deviation (SD) of 0.06, while the RMSD for the 2OVH protein-ligand complex ranged from 0.08 to 0.42 Å, with an average of 0.20 Å and a SD of 0.06 showing stable interaction. In principal component analysis, the observed eigen values of HPR-Tanshinone-I fluctuate between -1.11 to 1.48 and -1.07 to 1.25 for PC1 and PC2, respectively (1E3K), and the prog-tanshinone-I complex shows eigen values of -38.88 to -31.32 and -31.32 to 35.87 for PC1 and PC2, respectively (2OVH), which shows Tanshinone-I forms a stable protein-ligand complex with 1E3K in comparison to 2OVH. The Free Energy Landscape (FEL) analysis shows the Gibbs free energy in the range of 0 to 8 kJ/mol for Tanshinone-I with 1E3K and 0 to 14 kJ/mol for Tanshinone-I with the 2OVH complex. The DFT calculation reveals ΔE value of 2.8070 eV shows tanshinone-I as a stable compound. 1E3K modulates the prog pathway, it may have either an agonistic or antagonistic effect on hPRs. Tanshinone-I can cause ROS, apoptosis, autophagy (p62 accumulation), up-regulation of inositol requiring protein-1, enhancer-binding protein homologous protein, p-c-Jun N-terminal kinase (p-JNK), and suppression of MMPs. Bcl-2 expression can change LC3I to LC3II and cause apoptosis through Beclin-1 expression.
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Wearable devices are burgeoning, and applications across numerous verticals are emerging, including human performance monitoring, at-home patient monitoring, and health tracking, to name a few. Off-the-shelf wearables have been developed with focus on portability, usability, and low-cost. As such, when deployed in highly ecological settings, wearable data can be corrupted by artifacts and by missing data, thus severely hampering performance. In this technical note, we overview a signal processing representation called the modulation spectrum. The representation quantifies the rate-of-change of different spectral magnitude components and is shown to separate signal from noise, thus allowing for improved quality measurement, quality enhancement, and noise-robust feature extraction, as well as for disease characterization. We provide an overview of numerous applications developed by the authors over the last decade spanning different wearable modalities and list the results obtained from experimental results alongside comparisons with various state-of-the-art benchmark methods. Open-source software is showcased with the hope that new applications can be developed. We conclude with a discussion on possible future research directions, such as context awareness, signal compression, and improved input representations for deep learning algorithms.
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Dispositivos Eletrônicos Vestíveis , Algoritmos , Artefatos , Humanos , Monitorização Fisiológica , Processamento de Sinais Assistido por ComputadorRESUMO
Osteogenesis imperfecta (OI), also known as "brittle bone disease," is a genetic bone disorder. OI bones experience frequent fractures. Surgical procedures are usually followed by clinicians in the management of OI. It has been observed physical activity is equally beneficial in reducing OI bone fractures in both children and adults as mechanical stimulation improves bone mass and strength. Loading-induced mechanical strain and interstitial fluid flow stimulate bone remodeling activities. Several studies have characterized strain environment in OI bones, whereas very few studies attempted to characterize the interstitial fluid flow. OI significantly affects bone micro-architecture. Thus, this study anticipates that canalicular fluid flow reduces in OI bone in comparison to the healthy bone in response to physiological loading due to altered poromechanical properties. This work attempts to understand the canalicular fluid distribution in single osteon models of OI and healthy bone. A poromechanical model of osteon is developed to compute pore-pressure and interstitial fluid flow as a function of gait loading pattern reported for OI and healthy subjects. Fluid distribution patterns are compared at different time-points of the stance phase of the gait cycle. It is observed that fluid flow significantly reduces in OI bone. Additionally, flow is more static than dynamic in OI osteon in comparison to healthy subjects. This work attempts to identify the plausible explanation behind the diminished mechanotransduction capability of OI bone. This work may further be extended for designing better biomechanical therapies to enhance the fluid flow in order to improve osteogenic activities in OI bone.
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Osteogênese ImperfeitaRESUMO
A thermal analysis of Cu-CuO/ blood nanofluids flow in asymmetric microchannel propagating with wave velocity is presented in this study. For the blood, a micropolar fluid model is considered to investigate the microrotation effects of blood flow. Thermal radiation effects and the influence of nanoparticle shape, electric double layer thickness, and electromagnetic fields on the flow are studied. Three types of nanoparticles shapes namely cylinder, bricks and platelets are taken into account. Governing equations are solved under the approximations of long wavelength, low Reynolds number, and Debye-Hückel linearization. Numerical computations are performed for the axial pressure gradient, axial velocity, spin velocity and temperature distribution. The effects of various physical parameters on flow and thermal characteristics are computed and their physical interpretation is also discussed. The outcomes indicate that the axial velocity of Cu-CuO/blood nanoparticles strongly depends on applied electromagnetic field and microrotation. The model's finding will be applicable in designing the smart electromagnetic micro pumps for the hemodialysis and lungs-on-chip devices for the pumping of the blood.
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Cobre/química , Campos Eletromagnéticos , Microcirculação , Técnicas Analíticas Microfluídicas , Microvasos/fisiologia , Modelos Cardiovasculares , Nanopartículas , Temperatura , Animais , Velocidade do Fluxo Sanguíneo , Humanos , Hidrodinâmica , Fluxo Pulsátil , Fluxo Sanguíneo Regional , Rotação , Fatores de TempoRESUMO
INTRODUCTION: Laparoscopic pyloromyotomy (LP) for the treatment of infantile hypertrophic pyloric has advantage of smaller incisions, faster recovery, reduction in wound-related complications and better cosmesis. Various laparoscopic knives and spreaders have been used for LP, but they do not provide the depth and tissue perception as in open surgery. We describe the laparoscopic hybrid pyloromyotomy (LHP) which makes procedure simple and safe without the requirement of any special instrument. MATERIALS AND METHODS: This retrospective and prospective comparative study was conducted over a period of 4.5 years in a tertiary teaching hospital in central India. All patients with infantile hypertrophic pyloric stenosis diagnosed on the basis of clinical history, examination and ultrasonography were included in the study. Retrospective data of three-port conventional LP (CLP) using monopolar diathermy hook for incision was used as control group against prospective data of 25 patients undergoing LHP. After a proper layout, LHP was done using one umbilical optical port, right paraumbilical grasper of holding the pyloric olive and an epigastric incision for hybrid pyloromyotomy using 11 no blade and blunt-tipped mosquito artery forceps. RESULTS: Prospective group of LHP included 25 patients which were compared with a retrospective group of CLP consisting of 25 patients. On comparison of two groups, it was found that LHP reduces operative duration significantly. The outcome in terms of complications and recovery was comparable in two groups. None of the patients developed recurrence and required any redo surgery. CONCLUSION: LHP is a simplified approach which is easy to learn and teach, improves safety and accuracy of the procedure.
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Dynamic loading on the bone is beneficial in prevention and cure of bone loss as it encourages osteogenesis (i.e., new bone formation). Loading parameters such as strain magnitude, frequency, cycles, and strain rate (depending on loading waveform) affect the new bone formation. In-vivo studies suggested an optimal and osteogenic range of strain magnitude, frequency, and cycles to elicit the maximum new bone response. Still, there is no consensus on the selection of loading waveform. Animal studies on bone adaptation considered sinusoidal, and non-sinusoidal (e.g., trapezoidal, sawtooth, and triangular) loading waveforms according to physiological loadings (e.g., walking, running, and jumping etc.) without considering the relative effect of these waveforms on the loading-induced mechanical environment. The present study attempts to bridge this gap. Accordingly, this work hypothesizes that bone being a biphasic material (solid and fluid phases) experiences the same strain distribution for the different loading waves of the same amplitude, however, other components of the mechanical environment such as pore-pressure and interstitial fluid motion regulating the bone adaptation may differ. An in-vivo cantilever bending study is selected to substantiate the hypothesis. A poroelastic model is used to estimate the pore pressure and fluid motion developed in mouse tibia subjected to the: (i) trapezoidal, (ii) sawtooth, and (iii) triangular bending waves. Furthermore, poroelastic response of pore-pressure and fluid motion induced by these loading waveforms are compared and analyzed. This work also investigates how bone loss associated alterations in the microstructural environment of cortical bone affect the canalicular fluid motion induced by these waveforms. Overall results may be useful in designing optimal biomechanical interventions such as physical exercises to improve the bone health.
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Adaptação Fisiológica , Líquido Extracelular/metabolismo , Modelos Biológicos , Osteogênese/fisiologia , Estresse Mecânico , Tíbia/crescimento & desenvolvimento , Animais , Camundongos , Suporte de CargaRESUMO
Mental workload assessment is crucial in many real life applications which require constant attention and where imbalance of mental workload resources may cause safety hazards. As such, mental workload and its relationship with heart rate variability (HRV) have been well studied in the literature. However, the majority of the developed models have assumed individuals are not ambulant, thus bypassing the issue of movement-related electrocardiography (ECG) artifacts and changing heart beat dynamics due to physical activity. In this work, multi-scale features for mental workload assessment of ambulatory users is explored. ECG data was sampled from users while they performed different types and levels of physical activity while performing the multi-attribute test battery (MATB-II) task at varying difficulty levels. Proposed features are shown to outperform benchmark ones and further exhibit complementarity when used in combination. Indeed, results show gains over the benchmark HRV measures of 24.41 % in accuracy and of 27.97 % in F1 score can be achieved even at high activity levels.
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INTRODUCTION: Since the first description by William Ladd, the Ladd's procedure has been the surgery of choice for the correction of malrotation. The laparoscopic Ladd's procedure is becoming popular with the advent of minimal access surgery and is described in the literature. Various techniques of the Ladd's procedure have been described but none of them describes the stepwise technique for derotation of volvulus which is the most difficult and confusing part of the surgery. We describe 'steering wheel' technique for easy derotation of volvulus associated with malrotation. METHOD: A total of 62 patients were diagnosed to have an intestinal malrotation between 2010 and 2017. All cases which had complete non-rotation with a midgut volvulus were reviewed. Out of these, 48 patients were operated with open technique and 14 patients were subjected to the laparoscopic correction. TECHNIQUE: Using three-port technique, stepwise derotation of volvulus is done which simulates the rotation of steering of car at an acute turn and has been described in four simple steps. This technique also stresses the importance of the release of Ladd's band before derotation. RESULTS: Of 62 patients diagnosed with malrotation, 14 (22.6%) patients underwent the laparoscopic Ladd's procedure. The mean age was 26 + 8 months, mean weight was 10 + 2 kg and included eight males (57%) and six females (43%). There was only one (7.14%) conversion to open technique, due to a huge dilatation of duodenum causing difficulty in dissection in a patient with malrotation without volvulus. The laparoscopic Ladd's procedure took an average time of 70 ± 15 min. CONCLUSION: The laparoscopic 'steering wheel' derotation technique is easy and provides a stepwise description of the laparoscopic derotation of volvulus associated with malrotation in children.
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In vivo studies suggest that cyclic and low-magnitude loading can be useful over pharmaceutical drugs in normalizing bone loss as it encourages osteogenesis (i.e. new bone formation) at the sites of elevated strain magnitude. In silico models assumed normal strain or strain energy density (SED) as the stimulus to predict loading-induced osteogenesis, however, these models may have limited success in fitting the in vivo new bone formation at several instances. For example, rest-inserted cyclic loading amplifies the new bone formation as compared to continuous-cyclic loading even though similar strain magnitude were induced in both the cases. It is also believed that loading-induced interstitial fluid flow can also be a potential stimulus of osteogenesis. The present study hypothesizes that fluid motion as osteogenic stimulus may explain the afore-mentioned anomalies. Accordingly, this work studies osteogenesis as functions of SED and canalicular fluid motion using an in silico model. Therefore, the new bone formation is considered roughly proportional to stimuli above their osteogenic thresholds. This model attempts to simulate in vivo new bone formation noticed in rest-inserted cantilever loading studies. The model's prediction of site-specific new bone formation improves when fluid flow is considered as the stimulus. It is also noticed that fluid motion as the stimulus closely fits the new bone formation for another in vivo study where the effects of aging on osteogenesis were examined. These attempts to establish fluid flow as a potential osteogenic stimulus can be useful in the prediction of site-specific new bone formation. The findings will ultimately be useful in designing biomechanical interventions such as prophylactic exercises to cure bone loss.
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Adaptação Fisiológica/fisiologia , Osso e Ossos/metabolismo , Modelos Biológicos , Osteogênese/fisiologia , Animais , Simulação por Computador , Suporte de Carga/fisiologiaRESUMO
INTRODUCTION: Laparoscopic management of giant hydatid cyst has limitations such as spillage, poor control, difficulties in suctioning the contents through special ports which are not easily available, difficulty in the obliteration of residual cavity and recurrence. We describe single-incision trocar-less endoscopic (SITE) technique which simplifies enucleation and management of residual cavity. METHOD: Inclusion criteria for these cases were patients having single uncomplicated giant hydatid cyst >5 cm present at the surface of the liver and palpable on clinical examination. The cysts which were <5 cm, multiple, deep-seated and impalpable were excluded from the study. TECHNIQUE: An incision of 1 cm is marked over the site of the maximum bulge and deepened to open peritoneum, cyst is held with two stay sutures, injection of scolicidal agent and aspiration is done and suction of the cyst content is done. After suction of the contents, 5 mm telescope is inserted, and the cyst cavity is inspected, clearance and cyst procedure is done. RESULTS: In 6 years, 62 cases of giant hydatid cyst fulfilling the inclusion criteria and were taken for SITE technique. SITE was successful in all patients and none needed a conversion. Twenty-nine (46.77%) underwent omentopexy and three (4.83%) underwent SITE capitonnage. There was post-operative biliary leak in one (0.016%) patient who underwent capitonnage, which was managed by prolonged drainage which resolved in 10 days. Mean operative duration was 52 min (30 min to 85 min). Mean follow-up was for 18 months (12-36 months). One (0.016%) patient had cyst recurrence. DISCUSSION: SITE has advantages of endoscopic clearance and does not require special ports which are expensive, technically difficult to use and often unavailable. It allows controlled handling, effective suction and easier management of bile communication. SITE can be a preferred procedure for endoscopic management of giant liver hydatid cysts. CONCLUSION: SITE management of giant liver hydatid cyst seems to be a reliable treatment modality as it is minimally invasive, efficient, easy to perform and effective.
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A theoretical study is presented here for the electro-osmosis modulated peristaltic three-layered capillary flow of viscous fluids with different viscosities in the layers. The layers considered here are the core layer, the intermediate layer and the peripheral layer. The analysis has been carried out under a number of physical restrictions viz. Debye-Hückel linearization (i.e. wall zeta potential ≤25mV) is assumed sufficiently small, thin electric double layer limit (i.e. the peripheral layer is much thicker than the electric double layer thickness), low Reynolds number and large wavelength approximations. A non-dimensional analysis is used to linearize the boundary value problem. Fluid-fluid interfaces, peristaltic pumping characteristics, and trapping phenomenon are simulated. Present study also evaluates the responses of interface, pressure rise, time-averaged volume flow rate, maximum pressure rise, and the influence of Helmholtz-Smoluchowski velocity on the mechanical efficiency (with two different cases of the viscosity of fluids between the intermediate and the peripheral layer). Trapping phenomenon along with bolus dynamics evolution with thin EDL effects are analyzed. The findings of this study may ultimately be useful to control the microvascular flow during the fractionation of blood into plasma (in the peripheral layer), buffy coat (intermediate layer) and erythrocytes (core layer). This work may also contributes in electrophoresis, hematology, electrohydrodynamic therapy and, design and development of biomimetic electro-osmotic pumps.
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Simulação por Computador , Eletro-Osmose , Microcirculação , Microvasos/fisiologia , Modelos Cardiovasculares , Fluxo Pulsátil , Animais , Biomimética/métodos , Viscosidade Sanguínea , Humanos , Microvasos/anatomia & histologia , Fatores de TempoRESUMO
The present work reports an inverse electron demand Diels-Alder (iEDDA)-type reaction to synthesize 1,3,5-trizines from acetophenones and amidines. The use of molecular iodine in a catalytic amount facilitates the functionalization of the sp3 C-H bond of acetophenones. This is a simple and efficient methodology for the synthesis of 1,3,5-triazines in good to excellent yields under transition-metal-free and peroxide-free conditions. The reaction is believed to take place via an in situ iodination-based oxidative elimination of formaldehyde. DFT calculations at the M062X/6-31+G(d,p) level were employed to investigate the reaction mechanism. Reaction barriers for the cycloaddition as well as a formaldehyde expulsion steps were computed, and a multistep mechanism starting with the nucleophilic attack by benzamidine on an in situ generated imine intermediate has been proposed. Both local and global reactivity descriptors were used to study the regioselectivity of the addition steps.