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Covalent immobilization of molecular catalysts onto metal oxide surfaces through linker groups is a common strategy for heterogenizing homogeneous catalysts with the expectation that the immobilized catalyst will have properties similar to those of its molecular counterpart. However, the catalytic properties of the immobilized species are often quite different compared to their soluble counterparts in ways that are difficult to predict. This phenomenon is poorly understood and could be due to a variety of factors, including steric shielding of the complex by the surface, changes to the coordination sphere upon immobilization, or a lack of conformational flexibility of the immobilized complexes. Here, we tested the effect of surface immobilization on the catalytic activity and selectivity of atom transfer radical additions and cyclizations. In this study, we varied the proximity of the phosphonate anchoring group to the Cu center by attachment at varying positions of chelating nitrogen ligands such as 1,10-phenanthroline (phen), tris(pyridylmethyl)amine, and 2,9-dimethyl-1,10-phenanthroline as ligand scaffolds. Catalytic testing revealed that in cases where the anchoring group is remote from the catalytic center, as is the case for Cu(phen), the immobilized catalyst functions overall slightly better than its homogeneous counterpart (resulting in higher yields). However, for complexes in which the linker group is close to the active center, the catalytic performance of the immobilized complex was generally worse when immobilized than when in solution (decreased yield upon immobilization). Potential explanations of these observations are discussed. This study very clearly demonstrates the highly complex nature of immobilized catalysts and highlights the need for more in-depth comparisons between immobilized and soluble organometallic catalysts.

AbstractThis study is about the development of an Artificial Neural Network (ANN) based practical rapid assessment method for Reinforced Concrete (RC) buildings by using the minimum possible number of input data. The problem is formulated as a classification problem and evaluated as two sub-problems. Feed Forward Back Propagation (FFBP) and Generalized Regression Neural Networks (GRNNs) are used in each case and eight different ANN models are developed. To develop ANN models, a total of 402 residential building models are generated of three types and up to eight storeys. The earthquake performance of these building models is investigated through the nonlinear incremental mode combination method. By using the building properties as inputs and the results of structural analyses as outputs, the ANN models are trained and tested. Additionally, existing buildings are used for validation. The results show that the earthquake behavior of RC buildings can be predicted successfully using an ANN.

Consensusability of multiagent systems (MASs) certifies the existence of a distributed controller capable of driving the states of each subsystem to a consensus value. We study the consensusability of linear interconnected MASs (LIMASs), where, as in several real-world applications, subsystems are physically coupled. We show that consensusability is related to the simultaneous stabilizability of multiple LTI systems, and present a novel sufficient condition in form of a linear program for verifying this property. We also derive several necessary and sufficient consensusability conditions for LIMASs in terms of parameters of the subsystem matrices and the eigenvalues of the physical and communication graph Laplacians. The results show that weak physical couplings among subsystems and densely connected physical and communication graphs are favorable for consensusability. Finally, we validate our results through simulations of networks of supercapacitors and dc microgrids.

One of the most important structures in urban areas is an efficient sewer system to protect humans and the environment from the detrimental effects of wastewater. Such sewer systems often consist of pipes, manholes, pumping stations, and other complementary units. Strict monitoring of the sewer system is highly essential as any leakage can cause undesirable effects on health and safety. The layout is modeled as a graph which contains all sewer links and satisfies all the restrictions of a sanitary sewer system. In this work, we apply centrality measures on the sewer network system and water distribution system and also analyze the vulnerability of these systems.

Consensusability is an important property for many multi-agent systems (MASs) as it implies the existence of networked controllers driving the states of MAS subsystems to the same value. Consensusability is of interest even when the MAS subsystems are physically coupled, which is the case for real-world systems such as power networks. In this paper, we study necessary and sufficient conditions for the consensusability of linear interconnected MASs. These conditions are given in terms of the parameters of the subsystem matrices, as well as the eigenvalues of the physical and communication graph Laplacians. Our results show that weak coupling between subsystems and fast information diffusion rates in the physical and communication graphs favor consensusability. Technical results are verified through computer simulations.

The problem of replay attacks in the communication network between Distributed Generation Units (DGUs) of a DC microgrid is examined. The DGUs are regulated through a hierarchical control architecture, and are networked to achieve secondary control objectives. Following analysis of the detectability of replay attacks by a distributed monitoring scheme previously proposed, the need for a watermarking signal is identified. Hence, conditions are given on the watermark in order to guarantee detection of replay attacks, and such a signal is designed. Simulations are then presented to demonstrate the effectiveness of the technique.

This paper focuses on determination of the natural frequencies in slenderness pipe flows by considering fluid–structure interaction approach. Rayleigh beam theory is used to model the pipe. The fluid in the pipe is assumed as ideal, steady and uniform. Hamilton’s variation principle is demonstrated to obtain the equation of motion of pipe–fluid system. The dimensionless partial differential equations of motion are converted into matrix equations, and the values of natural frequencies of first three modes are archived with the analytical method. The results are arranged to be a data set for hybrid meta-heuristic artificial neural network (ANN) method. Three different meta-heuristic algorithms are used to train the ANN: particle swarm optimization (PSO) and artificial bee colony (ABC) and grey wolf optimizer (GWO). The comparison is presented to find a suitable algorithm based on accuracy for determining the natural frequency of the Rayleigh pipe conveying fluid. The results show that the PSO algorithm outperforms the other meta-heuristics in terms of performance indicators in prediction analysis. However, all algorithms and models can predict the natural frequencies with rate with satisfactory accuracy.

AbstractBackground/Aims:According to recent studies, the endocannabinoid system plays an important role in both physiological and pathophysiological situations. The purpose of the present study was to investigate the effects of cannabinoid (CB) agonists on isolated sheep sphincter of Oddi (SO)in vitro. Methods:The isolated sheep SO tissues were mounted in organ baths and tested for isometric tension and cyclic GMP levels (cGMP) in response to the non-selective CB receptor agonist WIN 55,212-2 and the potent CB1 receptor agonist methanandamide in the presence and absence of the selective CB1 antagonist SR 141716A, the selective CB2 antagonist SR 144528 and the nonspecific inhibitor of nitric oxide (NO) synthase L-NAME. Results:CB agonists relaxed SO in a concentration-dependent manner. These relaxations did not reduce in the presence of SR 144528 but were significantly reduced by SR 141716A and L-NAME. Carbachol significantly increased the cGMP levels compared with the control group and both of the CB receptor agonists significantly increased the cGMP levels compared with the control and carbachol groups. On the other hand, L-NAME prevented the increase in cGMP levels caused by CB agonists. Conclusion:These results show that the relaxation by the agonists may be through CB1 receptors. The decrease of CB relaxation responses by L-NAME, a nonspecific inhibitor of NO synthase, and the increase of cGMP levels in the SO tissues by CB agonists which decreased by L-NAME show that the relaxation effects of these agonists may also partially be via increasing the NO synthesis or release.Copyright © 2011 S. Karger AG, Basel and IAP

The advantage of partial splenectomy is the preservation of its immunologic function. In this series, 8 patients underwent a spleen preservation procedure with radiofrequency. Four of the partial splenectomy procedures were performed in elective situations, whereas the other 4 cases were performed to control traumatic bleeding in emergency situations. A harrow-like radiofrequency probe with 6 needles was applied to the spleen, and the division of the splenic parenchyma was completed using a surgical scalpel through the midline of the ablated tissue. This safe, fast, and simple technique allows for preservation of splenic function with minimum blood loss.

Background/Aims: According to recent studies, the endocannabinoid system plays an important role in both physiological and pathophysiological situations. The purpose of the present studywas to investigate the effects of cannabinoid (CB) agonists on isolated sheep sphincter of Oddi (SO) in vitro.Methods: The isolated sheep SO tissues were mounted in organ baths and tested for isometric tension and cyclic GMP levels (cGMP) in response to the non-selective CB receptor agonistWIN55,212-2 and the potent C131 receptor agonist methanandamide in the presence and absence of the selective CB1 antagonist SR 141716A, the selective CB2 antagonist SR 144528 and the nonspecific inhibitor of nitric oxide (NO) synthase I-NAME. Results: CB agonists relaxed SO in a concentration-dependent manner. These relaxations did not reduce in the presence of SR 144528 but were significantly reduced by SR 141716Aand I-NAME. Carbachol significantly increased the cGMP levels compared with the control group and both of the CB receptor agonists significantly increased the cGMP levels compared with the control and carbachol groups.On the other hand, I-NAME prevented the increase in cGMP levels caused by CB agonists. Conclusion: These results show that the relaxation by the agonists maybe through CB1 receptors.The decrease of CB relaxation responses by I-NAME, a nonspecific inhibitor of NO synthase, and the increase of cGMP levels in the SO tissues by CB agonists which decreased by I-NAME show that the relaxation effects of these agonists may also partially bevia increasing the NO synthesis or release.

A pilot-scale submerged membrane bioreactor (SMBR) with anoxic and oxic tanks was operated in an attempt to reduce the problems concerning effective removal of organic matter and nutrients from municipal wastewater. A fl at type membrane with a pore size of 0.038 μm and having a total surface area of 3.60 m2was used in the experiments. During the operation, MLSS concentration in aeration (oxic) tank of SMBR was maintained at about 5–7 g/l. Influent and effluent pH in the SMBR also changed between 7.3–8.4. Raw wastewater with average chemical oxygen demand (COD): total nitrogen (TN) ratio of 12:2 was treated at various temperatures (10–30 °C) over an interval of about 160 d. When average influent nutrient mass ratio (COD:TN:TP) was 100:8.2:1.2 and BOD5:COD ratio was 0.5, removal efficiencies of COD, BOD5, TSS, TN and TP were 99.1%, 99.3%, 99.4%, 43.4% and 68.2%, respectively. Nitrification occurred in the aerobic reactor with NH4+–N removal efficiency ranging from 88.7 to 99.7% averaging at 97.8%. Nitrogen removal in the SMBR was limited not by nitrification but by denitrification. Increase in the concentration of TN in the treated water can be explained by increases in the concentration of NO3-–N.

A pilot-scale submerged membrane bioreactor (SMBR) with anoxic and oxic tanks was operated in an attempt to reduce the problems concerning effective removal of organic matter and nutrients from municipal wastewater. A fl at type membrane with a pore size of 0.038μm and having a total surface area of 3.60 m2was used in the experiments. During the operation, MLSS concentration in aeration (oxic) tank of SMBR was maintained at about 5–7 g/l. Influent and effluent pH in the SMBR also changed between 7.3–8.4. Raw wastewater with average chemical oxygen demand (COD): total nitrogen (TN) ratio of 12:2 was treated at various temperatures (10–30 °C) over an interval of about 160 d. When average influent nutrient mass ratio (COD:TN:TP) was 100:8.2:1.2 and BOD5:COD ratio was 0.5, removal efficiencies of COD, BOD5, TSS, TN and TP were 99.1%, 99.3%, 99.4%, 43.4% and 68.2%, respectively. Nitrification occurred in the aerobic reactor with NH4+–N removal efficiency ranging from 88.7 to 99.7% averaging at 97.8%. Nitrogen removal in the SMBR was limited not by nitrification but by denitrification. Increase in the concentration of TN in the treated water can be explained by increases in the concentration of NO3-–N.

Nitric oxide (NO) is a potent nonadrenergic, noncholinergic mediator of gastrointestinal smooth muscle. We aimed to investigate the effects of new NO/cyclic guanosine monophosphate (cGMP) pathway-affecting agents at the sheep sphincter of Oddi (SO) in vitro.

AbstractBackground/Aims:Intravenous anesthetics are often used for conscious sedation in endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic sphincter of Oddi (SO) manometry. This study was designed to investigate the effects of propofol on sheep SO. Methods:SO rings were mounted in a tissue bath and tested for changes in isometric tension in response to propofol (10–8–10–4M) in the presence or absence of L-NAME (3 × 10–5M), a non-specific inhibitor of nitric oxide (NO) synthase; indomethacin (10–5M), an inhibitor of cyclooxygenase; glibenclamide (10–5M), an inhibitor of ATP-sensitive potassium channels; tetraethylammonium (3 × 10–4M), inhibitors of calcium-activated potassium channels; 4-aminopyridine (10–3M), a voltage-dependent potassium channel blocker. Furthermore, we investigated the Ca2+antagonist feature of propofol in precontracted SO rings by CaCl2. Results: Carbachol (10–9–10–5M) induced concentration-dependent contraction responses in the SO rings.Propofol (10–8–10–4M) produced concentration-dependent relaxation on isolated SO rings precontracted by carbachol (10–6M). Preincubation of SO rings by L-NAME (3 × 10–5M), indomethacin (10–5M), glibenclamide (10–5M), and 4-aminopyridine (10–3M) did not produce a significant alteration on propofol-induced relaxation responses (p > 0.05), while preincubation by tetraethylammonium (3 × 10–4M) significantly decreased the propofol-induced relaxation responses (p < 0.05). Propofol (10–8–10–4M) induced concentration-dependently relaxations in precontracted isolated SO rings by CaCl2. Conclusion:The results suggest that propofol induced concentration-dependent relaxations in precontracted isolated SO rings. These relaxations are independent from NO, cyclooxygenase metabolites, and opened ATP-sensitive and voltage-dependent potassium channels. Opened Ca2+-sensitive K+channels and inhibited L-type Ca2+channels existing in smooth muscle by propofol can contribute to these relaxations. Propofol can be beneficial as alternative drugs for obtaining selective relaxation during SO manometry after controlled clinical studies.Copyright © 2007 S. Karger AG, Basel and IAP

Background/Aims:Intravenous anesthetics are often used for conscious sedation in endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic sphincter of Oddi (SO) manometry. This study was designed to investigate the effects of propofol on sheep SO. Methods:SO rings were mounted in a tissue bath and tested for changes in isometric tension in response to propofol (10-8-10-4M) in the presence or absence of L-NAME (3 × 10-5M), a non-specific inhibitor of nitric oxide (NO) synthase; indomethacin (10-5M), an inhibitor of cyclooxygenase; glibenclamide (10-5M), an inhibitor of ATP-sensitive potassium channels; tetraethylammonium (3 × 10-4M), inhibitors of calcium-activated potassium channels; 4-aminopyridine (10-3M), a voltage-dependent potassium channel blocker. Furthermore, we investigated the Ca2+antagonist feature of propofol in precontracted SO rings by CaCl2. Results:Carbachol (10-9-10-5M) induced concentration-dependent contraction responses in the SO rings. Propofol (10-8-10-4M) produced concentration-dependent relaxation on isolated SO rings precontracted by carbachol (10-6M). Preincubation of SO rings by L-NAME (3 × 10-5M), indomethacin (10-5M), glibenclamide (10-5M), and 4-amino-pyridine (10-3M) did not produce a significant alteration on propofol-induced relaxation responses (p0.05), while preincubation by tetraethylammonium (3 × 10-4M) significantly decreased the propofol-induced relaxation responses (p < 0.05). Propofol (10-8-10-4M) induced concentration-dependently relaxations in precontracted isolated SO rings by CaCl2. Conclusion:The results suggest that propofol induced concentration-dependent relaxations in precontracted isolated SO rings. These relaxations are independent from NO, cyclooxygenase metabolites, and opened ATP-sensitive and voltage-dependent potassium channels. Opened Ca2+-sensitive K+channels and inhibited L-type Ca2+channels existing in smooth muscle by propofol can contribute to these relaxations. Propofol can be beneficial as alternative drugs for obtaining selective relaxation during SO manometry after controlled clinical studies.

Background/Aims: ATP-sensitive K+(KATP) channels play an important role in the regulation of smooth muscle membrane potential. This study was designed to investigate the effects of pinacidil and cromakalim, KATPsensitive channel activators, on sheep sphincters of Oddi (SO). Methods: SO rings were mounted in a tissue bath and tested for changes in isometric tension in response to pinacidil (10-9-10-4M) and cromakalim (10-9-10-4M) in the presence or absence of glibenclamide (10-6M), a blocker of KATP channels. Furthermore, concentrationdependent contraction responses of carbachol were obtained. Results: Carbachol (10-9-10-5M) induced concentration-dependent contraction responses in the SO rings. Pinacidil (10-9-10-4M) and cromakalim (10-9-10-4M) induced concentration-dependent relaxation in isolated SO rings precontracted with carbachol (10-6M). At their maximum effects, both pinacidil and cromakalim produced nearly full relaxation. In the presence of glibenclamide, concentration-relaxation curves for pinacidil and cromakalim underwent rightward parallel shifts. There were no significant differences between p EC50and Emaxvalues of pinacidil and cromakalim in the absence of glibenclamide (10-6M) (p 0.05), but p EC50values of pinacidil and cromakalim in the presence of glibenclamide (10-6M) were significantly reduced (p < 0.05). Conclusion: These results suggest that the relaxation caused in sheep SO by pinacidil and cromakalim is mediated through the same glibenclamide-sensitive KATP channel. Pinacidil and cromakalim have an equipotent relaxing effect in isolated sheep SO and they can be beneficial as alternative drugs for obtaining selective relaxation during SO manometry after controlled clinical studies.

Paragangliomas are uncommon tumors arising from the neuroendocrine elements of the paraganglia. Their successful management is associated with many problems. We herein present the findings of a 22-year-old man in whom a paraganglioma was incidentally found and in which the clinical and previous operative behavior was functioning desensitization. As a result, preoperative medication was not performed; however, during the tumor resection the patient demonstrated hemodynamic instability.

Purpose Ca 2+ channel blockers inhibit collagenase production and have a vasodilatatory effect. They also restrict the formation of ischemia-reperfusion induced free oxygen radicals. The aim of this study was to assess the effect of nifedipine on the healing of colonic anastomoses in a rat model. Methods Sixty Wistar rats weighing 240–290?g were divided into four groups of 15 rats each: a 3rd day control group (group A), a 3rd day treatment group (group B), a 7th day control group (group C), and a 7th day treatment group (group D). The treatment groups were given Nifedipine 3?mg/kg per day orally as three divided doses. Results The bursting pressure values of the anastomoses in the treatment groups were significantly higher than those in the control groups ( P « 0.05). The hydroxyproline content was also significantly higher in the treatment groups than in the control groups ( P « 0.05). Histologic examination confirmed that nifedipine treatment significantly increased collagen deposition and fibroblast ingrowth compared with controls ( P « 0.05). Conclusions These results clearly showed that nifedipine enhanced the stability of colonic anastomoses during the first postoperative week.

Abstract.: A 47-year-old man with long-standing Behçet's syndrome presented with an acute abdomen, and was found to have perforation of the sigmoid colon. Laparotomy revealed gangrenous changes in the sigmoid colon and perforation in the center of the affected segment. This is a very rare complication of Behçet's disease, and we report this case to stress the importance of performing careful abdominal examination while evaluating patients with Behçet's disease.

Abstract.: Purpose: The levels of thyroid hormones decrease in septic, critically ill, and major trauma patients who show a bad prognosis. The aim of this study was to investigate the effects of thyroid hormone supplementation on the sepsis criteria and mortality in an experimental sepsis model. Methods: Forty-eight Wistar-Albino rats were divided into four experimental groups. A cecum ligation and puncture was used as a sepsis model. Group I: sham; group II: a cecum ligation and puncture (control); group III: a cecum ligation and puncture +T3 (0.4 μg/100 g body weight/day) intraperitoneally; group IV: a cecum ligation and puncture +T4 (1 500 ng/100 g body weight/day) intramuscularly. The PCO2, leukocyte count, peritoneal bacterial content, neutropenia, and mortality rates were assessed in all groups. Results: The PCO2 levels decreased only in the control group (P < 0.05). The leukocyte counts were lower in the therapy groups (P < 0.05). The rate of neutropenia was seen much more in the control group (P < 0.05). The peritoneal bacteria content decreased in the therapy groups (P < 0.05). The mortality rate significantly decreased in the thyroid hormone-treated animals (P < 0.05). Conclusions: Thyroid hormone supplementation in septic rats had a beneficial effect on the sepsis criteria and also resulted in a lower rate of mortality.

Abstract.: Purpose: The operative strategy for left-sided large bowel obstruction remains controversial. Because a safe and definitive single-staged operation that avoided a colostomy would clearly be in the patients' best interest, we conducted a prospective study to compare the efficacy of single-staged surgery (SSS) supplemented by the milking and swabbing technique (MST), with the conventional Hartmann's procedure (HP). Methods: In group 1 (n = 37) we performed traditional HP by resecting the site of obstruction and constructing an end colostomy. In group 2 (n = 33), after resecting the site of obstruction, instead of on-table lavage, we cleaned out the fecal content from the proximal and distal parts of the obstruction by milking the colon with the fingers, then swabbing the proximal and distal 10 cm of lumen of the colonic anastomosis with povidone iodinized stick sponges. Finally, we performed a primary one-layer anastomosis without fecal diversion. Results: The mortality, morbidity, and postoperative hospital stay after emergency left-side colonic resection and primary anastomosis by MST was comparable with those after HP (P > 0.05). Conclusions: We believe that SSS with MST is a viable choice in the surgical management of selected patients with obstructing lesions of the left colon. The advantages of SSS with MST lie in its good long-term results, and short-term reduced surgical intervention and hospital stay.

Nephrotoxicity is one of the most frequent dose-limiting factors of high-dose chemotherapy to create tolerance of autologous peripheral blood stem-cell transplantation (PBSCT) for the treatment of malignant diseases. The relative importance of factors that may be responsible for the development of nephrotoxicity varied in different trials.

AbstractPeripancreatic tuberculous lymphadenitis is a very rare and difficult diagnosis. We report herein a patient with a clinically solitary abdominal tuberculoma. A 68-year-old woman was admitted to our hospital with moderate-level obstructive jaundice due to a mass located between pylorus and head of the pancreas. There were no clinical signs or symptoms of tuberculosis in lungs or abdomen. After the diagnosis of a neoplasm of the pancreas was made, exploratory laparotomy was performed which revealed a conglomerated mass penetrating into the pancreas. Since an exact diagnosis could not be reached on the basis of frozen sections prepared during the operation, a standard Whipple procedure was performed. After the histopathological examination of the resected specimen revealed tuberculous lympadenitis, the patient was given antituberculous medication. The patient recovered well. An abdominal tuberculoma is often mistaken for a malignant neoplasm, and nonsurgical diagnosis and treatment of this entity continues to be a challenge.Copyright © 2002 S. Karger AG, Basel and IAP

Peripancreatic tuberculous lymphadenitis is a very rare and difficult diagnosis. We report herein a patient with a clinically solitary abdominal tuberculoma. A 68-year-old woman was admitted to our hospital with moderate-level obstructive jaundice due to a mass located between pylorus and head of the pancreas. There were no clinical signs or symptoms of tuberculosis in lungs or abdomen. After the diagnosis of a neoplasm of the pancreas was made, exploratory laparotomy was performed which revealed a conglomerated mass penetrating into the pancreas. Since an exact diagnosis could not be reached on the basis of frozen sections prepared during the operation, a standard Whipple procedure was performed. After the histopathological examination of the resected specimen revealed tuberculous lympadenitis, the patient was given antituberculous medication. The patient recovered well. An abdominal tuberculoma is often mistaken for a malignant neoplasm, and nonsurgical diagnosis and treatment of this entity continues to be a challenge.

Selenium (Se), zinc (Zn), copper (Cu), and antioxidant enzyme (superoxide dismutase [SOD] and glutathione peroxidase [GSH-Px]) levels in sera were detected in Behçet patients. Age and sex matched controls were used to find out if oxidative stress takes place in the etiopathogenesis of Behçet’s disease. Superoxide dismutase levels were found to be lower in the whole patients group when compared to controls. In whole patients and inactive patients’ group Zn and Se levels were found to be higher, but not different in the active patients group when compared to controls. No significant difference was found between the groups as Cu and glutathione peroxidase levels were taken into consideration. According to the results of the present study, SOD level is low in Behçet’s disease patients’ sera independent from the phase of the disease, and as a result of decreased SOD activity, increased production of free oxygen radicals may play a role in the etiopathogenesis of the disease.

Backwashing of deep bed filters is achieved by fluidizing the filter media. A mathematical model for velocity gradient in two‐dimensional turbulent flow that can also be applied to flow in fluidized beds in the transitional state was developed. The theory of fluidization in a circular cross‐section column was presented. The existence of a viscous sublayer around each fluidized solid particle and the laminar sublayer thickness at the wall were neglected. To evaluate the theoretical expressions, numerical applications are carried out for filter‐bed materials of two different types of sands and anthracite coal. An indirect verification of the existence of an optimum porosity around 0.70‐0.75 during filter backwashing was observed in the laboratory experiments. The velocity gradient in backwashing of granular filters was found to be a function of power dissipation in a unit volume and coefficient C that indicates the effect of turbulence in total power dissipation. It was also found that turbulence intensity decreases with an increase of porosity, and the arithmetic mean shear stress has a maximum value between porosity values of 0.70 and 0.75.

Reduced lumbar lordosis may make the process of identifying the intervertebral distance easier. The primary aim of this study was to measure the L3–L4 intervertebral space in the same patients undergoing spinal anesthesia in three different sitting positions, including the classic sitting position (CSP), hamstring stretch position (HSP) and rider sitting position (RSP). The secondary aim was to compare ultrasonographic measurements of the depth of the ligamentum flavum and intrathecal space in these three defined positions.

Abstract.: We report the case of an 18-year-old, mentally retarded boy who suffered acute abdominal symptoms and signs after eating a heavy meal. Laparotomy showed massive gastric dilatation with near-total infarction and perforation. Total gastrectomy and esophagojejunostomy were performed, but the patient died a few hours after the operation.