Most of the continuum robots have flexible backbones that are deformed under the internal and external loads and a considerable amount of potential energy may be stored in the backbone. Hence, the continuum robots are exposed to instability issues such as SNAP-THROUGH. The SNAP-THROUGH instability occurs when, with changes in the applied forces, the robot reaches the boundary of its stable region and then moves toward a stable configuration in an uncontrolled manner. SNAP-THROUGH instability is harmful to the continuum robots and its prediction is important for the design and control of the robot. However, most of the studies focused on design, kinematics, and dynamics of the continuum robots and there are limited studies worked on stability analysis of these robots. In this paper, the stability analysis of the cable-driven continuum robots is investigated. For this, the static equilibrium configurations of the robot are firstly determined under the internal and external loadings. Then, the stiffness matrix of the robot is obtained and the robot stability and SNAP-THROUGH condition are evaluated. The accuracy of the static equations of the robot is verified using the experimental results and the possibility of SNAP-THROUGH occurrence is modeled THROUGH simulations. Besides, the effects of the external loads, robot configuration in space, and cross-section of the backbone on the workspace and SNAP-THROUGH occurrence are studied.

Introduction: More than 30 Acute Kidney Injury (AKI) definitions exist in the published literature and there is no consensus especially in neonatal group. Chevalier and colleagues defined neonatal acute renal failure as serum creatinine values>1.5 mg/dL for at least 24 hours. Acute Renal Failure (ARF) affects approximately 1% to 24% of newborns in the Neonatal Intensive Care Units (NICUs). ARF is a significant factor of morbidity and mortality in critically ill children. The Acute Dialysis Quality Initiative (ADQI) group has recently proposed the RIFLE criteria for AKI in adults. The RIFLE acronym stands for risk, injury, failure, loss of kidney function and end-stage renal disease. This classification system to define AKI in neonatal group has not been performed. We hypothesized that critically ill neonates with ARF based on old definition (serum creatinine more than 1.5 mg/ dL) have decreased survival, independent of demographic characteristics, co-morbidities, clinical parameters, severity of illness and interventions variables known to predict infant survival.According to this hypothesis, we evaluated urine output, serum creatinine, and glomerular filtration rate in critically ill neonates and compared them to RIFLE scoring system.Methods: This cohort study was conducted at the neonatal intensive care units of Mofid and Mahdieh hospitals which are two of the largest referral neonatal hospitals in Tehran. There are about 4400 deliveries annually in the Mahdieh hospital and about 2000 admissions to the both neonatal intensive care units each year. Between March 2006 and May 2009 all neonates transferred to these NICUs were enrolled for the study in a prospective manner. We determined GFR, urine output, mortality, morbidity, and the RIFLE scorefor each neonate. We also evaluated CRIB, CRIB II, SNAP, SNAPII and SNAP-PE score for each neonate and the final scores were then obtained by the arithmetic sum of individual scores of these parameters. The predictive accuracy of these receivers were expressed as area under the receiver operative characteristic (ROC) curve for each score and help to compare the performance of different tests, by plotting sensitivity, specificity, PPV and NPV. All groups were statistically analyzed by the t test and logistic model was used to analyze the prediction of mortality. The ethics committee of the Shahid Beheshti medical university and pediatric infectious research center approved this study.Results: We evaluated 404 neonates of NICUs of Mofid and Mahdieh hospitals during 2007 to 2009. Based upon RIFLE scoring system, 22.5% (91 neonates) of our study group had normal renal function and 77.5% (313 neonates) of them had abnormal renal function at the second day of admission. Therefore 313 neonates (77.5%) developed AKI by RIFLE criteria and among them 43% (135 neonates) met the risk, 51% (161 neonates) the injury and about 6% (17 neonates) the failure criterion. Based on old definition of ARF in neonates the rate of ARF in our study group was 3.2% (13 out of 404 neonates had serum creatinine more than 1.5 mg/dL), P<.001. In this study, we detected an overall in-hospital mortality of 20.5% in critically ill neonates. Of those who died, 81.9% (68 of 83 patients) had AKI. In patients with normal renal function, the rate of mortality was 16.5% and in patients with AKI based on RIFLE scoring system the mortality rate was 21.7% (P<.31). In R (risk) group the mortality rate was 16.3%, in I (injury) group the mortality rate was 24.2% and in F (failure) group the mortality rate was 41.2%.In patients with ARF based on creatinine level definition (serum creatinine more than 1.5 mg/dL) the mortality rate was 61.5% (P<.001, OR=6.741).A progressive and significant elevation in mortality was correlated with increasing RIFLE classification severity among all patients. (OR=1.406, P=.042, CI=0.76 to 2.06). The patients who had any degree of AKI at the time of admission to the NICU as well as those who had normal renal function had statistically significant higher median CRIB, CRIB II, SNAP, SNAP II and SNAP-PE NICU scoring systems, lower levels of apgar score, serum PH, serum bicarbonate and platelet count and wereyounger and smaller. Injury group on admission was associated with higher mortality than Risk group on admission (P<.001) and patients who developed Failure criteria during NICU stay had higher mortality than those who developed Risk group criteria (OR=3.17) or Injury group (OR=1.84).Conclusions: We concluded that a RIFLE criterion is a practical method to define AKI in neonatal group and it will be a good predictive tool for morbidity and mortality in NICUs.

In the present paper, the dynamical SNAP-THROUGH of a preloaded micro-sensor is analyzed. This behavior is linked to analyzing bifurcation behavior of the micro structure in a suitable framework. Effects of the axial pre-stress and the excitation amplitude on the stability and sensitivity of the sensor are also discussed. In order to capture the size effects, the modified strain gradient theory is employed on an Euler-Bernoulli beam. Applying the Hamilton’ s principle and utilizing the Galerkin’ s method, the nonlinear governing equation for the vibration is obtained. The method of multiple scales (MMS) is then used to obtain the frequency-response equation and by using a mathematical approach, the bifurcation points and the jump heights of the micro-resonator are analyzed. The calculated analytic equation for frequency response, provides the conditions for obtaining the range of SNAP-THROUGH and studying the effects of different designing parameters on the multivaluedness range. The jump height of the micro-resonator is proposed to use as a criterion for sensing purposes. The simulations are illustrated and the results are verified with similar works.

Background & Objectives: Clostridial neurotoxin inhibits neurotransmitter release by selective and specific intracellular proteolysis of synaptosomal associated protein of 25KDa (SNAP-25), synaptobrevin/VAMP-2 and syntaxin. SNAP-25 is one of the components that forms docking complex in synaptic ends. This protein is subtrate for botulinum neurotoxins types A, C, and E. Each of these toxin serotypes specifically cleaves SNAP-25 in a particular position and thereby blocks docking and synaptic vesicle membrane fusion and finally prevents neurotransmitter exocytosis and transition of neurotic signals. Recombinant production of SNAP-25 in the laboratory can be used as a subtrate for the detection of clostridium botulinum types A, and E neurotoxins.Materials & Methods: In order to use the protein as a subtrate for detection of different types of clostridium neurotoxins in-vitro the protein was produced by recombinant technique. The cDNA from SNAP-25 was synthesized from total RNA purified from frozen Rattus norvegicus brain and amplified by RT-PCR the amplified fragment was cloned into pET32a expression vector. The identity of recombinant protein was confirmed by Western blot using specific antibody and finally the recombinant protein was purified THROUGH an affinity column chromatography (Ni-NTA).Results: The optimum conditions of expression of SNAP-25 were found to be IPTG (1mM) and incubation at 37oc for 5 hours. The recombinant protein was isolated and purified using Ni-NTA column with imidazole at a concentration of 25OmM. Using enterokinase to cut the fision at 37oC comparatively yielded better results than room temperature.Conclusion: The protein retained its structure during the purification process being suitable for cutting and further tests. The purified protein we obtained can be used as substrate for detection of clostridium botulinum types A, and E toxins.

Background and purpose: There is growing interest in employing screening procedures to identify critical infants at the beginning of hospitalization at NICU and adjusting death rate with severity of early disease. Most of studies were carried out on preterm infants born in the same center. The aim of this study was to compare the diagnostic power of SNAP-PE, SNAP, and CRIB indices in determining the severity of disease and predict the mortality of neonates referred from other centers to NICU of Bou-Ali Sina Hospital, Sari, and compare them regardless of age at birth.Materials and methods: All newborns admitted the NICU with whatever age and birth weight less than 1500 grams compared with infants weighing 1500 grams or more during the first 24 hours of hospitalization by disease severity were evaluated by questionnaires SNAP-PE, SNAP, CRIB from January 2005 to April 2007. Patients due to death or early discharge in less than 24 hours or with lethal congenital anomalies were excluded from the study. The median score obtained in discharged or expired patients compared by Mann-Whitney U Test and the diagnostic power and differentiation of the three tools were compared using ROC curves. Cut point (cut off) of each tool was calculated and sensitivity, specificity, NPV, PPV was obtained respectively.Results: Out of 200 studied neonates, 60 patients (30%) expired. Median SNAP-PE, SNAP, CRIB was higher in the diet patients. Appropriate cut-off point based on the ROC curve for the CRIB was 6 and 10 for SNAP and was 12 for SNAP-PE. The area under the curve was 0.918 for the CRIB, 0.886 for SNAP, and 0.89 for SNAP-PE and all three tools were statistically significant (P<0.000). Sensitivity and specificity SNAP-PE, SNAP, CRIB for predicting neonatal death in infants weighing less than 1500 grams was lower than infants weighing 1500 grams and more.Conclusion: SNAP-PE, SNAP, and CRIB are suitable methods for predicting death and determine the severity of the disease in neonates. Therefore using these methods is recommended even for patients who referred to the NICU.

The behavior of compression members within a double-layer space truss has a commanding influence on the overall behavior of the structure. Using finite element method, a bar element with a piecewise linearized axial stress-strain relationship has been used to represent the ideal behavior of each member in collapse analysis of the double layer space trusses. According to static collapse analysis of double-layer space trusses, three different collapse mechanisms will be possible, namely: overall collapse of the structure, local collapse of the structure with dynamic SNAP-THROUGH, and local collapse of the structure without SNAP-THROUGH. In the case of local collapse with a SNAPTHROUGH, it has been indicated that to evaluate realistic response of the structure, the static collapse analysis is not adequate by itself, and a dynamic SNAP-THROUGH analysis must be performed, as well. In this paper, a methodology based on energy methods is presented to determine dynamic SNAP-THROUGH response of truss type structures. Finally a typical double-layer grid structure has been used to describe the approach and show three different possible collapse mechanisms.

The present article deals with introducing and critically studying the book Descartes Embodied: Reading Cartesian Philosophy THROUGH Cartesian Science by Daniel Garber. Garber, one of the most prominent researchers of modern philosophy and contemporary Descartes-scholar, wrote the book in 1980, and it was published by Cambridge University Press. This work has been released in French, yet there is no Persian translation available. It is a collection of articles written separately by author and published in credible philosophical journals. The unifying subject of the articles is the relationship between Descartes’ philosophical and scientific areas of interest. This article intends to introduce the author and covers the literary style of the book in English in brief. The article mainly addresses the introduction and critical analysis of the book itself, in two parts successively: form and content. This article intends to introduce the author and covers the literary style of the book in English in brief. The article mainly addresses the introduction and critical analysis of the book itself, in two parts successively: form and content.

One of the remarkable concerns in Shallow arches’ behavior under lateral loading is SNAP-THROUGH, aphenomenon which can make the structure collapse or displace to another stable configuration.Introducing functionally graded materials in recent years has led to some interesting results, forinstance, using functionally graded materials in shallow arches can produce structures with favorablestability properties. In this work, we investigate dynamic stability of the pined-pined functionallygraded sinusoidal shallow arch under impulsive loading. Material properties vary THROUGH the thicknessby power law function. Nonlinear governing equations are derived using Euler-Bernoulli beamassumption and equations of motion are expressed by a nonlinear differential-integral equation. Thesolution utilizes a Fourier form of response. The procedure to analyze dynamic stability followed hereuses total energy of the system and Lyapunov function in the phase space. We find the stable regionagainst dynamical SNAP-THROUGH under material properties’ variation in the thickness direction ofshallow arch. We also proceed to find the sufficient critical load in order to make the dynamical SNAPTHROUGH occur. The results are analyzed in detail and illustrated in some diagrams.