Testing and modeling of unsaturated interfaces.

A conventional fully automated direct shear test device was modified to achieve the objectives of this study. The newly developed device, called the Unsaturated Interface Direct Shear Apparatus (UIDSA), was equipped for applying and maintaining suction as well as net normal stress. The UIDSA can be used to conduct constant water content and constant suction tests on unsaturated soil and unsaturated interfaces.The performance of the newly developed device was checked and effects of net normal stress, suction, and roughness were investigated. Net normal stresses of 105, 140, and 210 kPa were used and were conducted under constant suction values of 20, 50, and 100 kPa.An existing elastoplastic constitutive model was modified to predict the behavior of interfaces between unsaturated soil and steel. The model is applicable for the constant net normal and constant suction conditions. Model parameters are function of net normal stress, suction, and surface roughness. Predictions made with the modified elastoplastic model agreed well with the experimental results.Results presented in this study suggest that the maximum shear stress of interfaces between unsaturated soil and steel is a function of net normal stress and suction. As net normal stress and suction increased, so did the shear strength. The results of this study indicate that matric suction contributed to the peak shear strength of unsaturated interfaces; however, residual shear strength did not vary with the matric suction. As opposed to the matric suction, variation in net normal stress affected both peak and residual shear stress. The influence of matric suction was more pronounced in soil than interfaces. Similar to soil samples, the rough interface showed increase in dilatancy with increase in suction, whereas the smooth interface did not show dilatancy behavior.Major device modifications included the construction of an air pressure chamber and testing cells for holding soil and counterfaces, addition of high air entry porous stones, addition of a pore water and pore air control system, and other modifications to accommodate the new apparatus. For saturated soil testing, a High Air Entry Porous Disk (HAEPD) was fixed in the bottom half of the shear box, whereas for interface testing the HAEPD was fixed in the top platen and was placed on top of the soil during testing.The extended Mohr-Coulomb failure criterion provided a good model for describing variation in interface shear strength as a function of net normal stress and matric suction. Shear strength parameters for soil and interfaces were determined to define the extended Mohr-Coulomb failure envelope.Research was conducted at the University of Oklahoma to examine the behavior of interfaces in unsaturated soil. The objectives of this research were to: (1) design and construct an apparatus for testing unsaturated interfaces and soil; (2) test unsaturated soil and interfaces in the new device to study the strength and volumetric behavior of unsaturated soil and interfaces; (3) examine application of the Mohr-Coulomb failure criterion to unsaturated interfaces; and (4) develop an elastoplastic model to account for the effect of suction and net normal stress on the behavior of an unsaturated interface

PTTG/securin activates expression of p53 and modulates its function

BACKGROUND: Pituitary tumor transforming gene (PTTG) is a novel oncogene that is expressed abundantly in most tumors. Overexpression of PTTG induces cellular transformation and promotes tumor formation in nude mice. PTTG has been implicated in various cellular processes including sister chromatid separation during cell division as well as induction of apoptosis through p53-dependent and p53-independent mechanisms. The relationship between PTTG and p53 remains unclear, however. RESULTS: Here we report the effects of overexpression of PTTG on the expression and function of p53. Our results indicate that overexpression of PTTG regulates the expression of the p53 gene at both the transcriptional and translational levels and that this ability of PTTG to activate the expression of p53 gene is dependent upon the p53 status of the cell. Deletion analysis of the p53 gene promoter revealed that only a small region of the p53 gene promoter is required for its activation by PTTG and further indicated that the activation of p53 gene by PTTG is an indirect effect that is mediated through the regulation of the expression of c-myc, which then interacts with the p53 gene promoter. Our results also indicate that overexpression of PTTG stimulates expression of the Bax gene, one of the known downstream targets of p53, and induces apoptosis in a human embryonic kidney cell line (HEK293). This stimulation of bax expression by PTTG is indirect and is mediated through modulation of p53 gene expression. CONCLUSIONS: Overexpression of PTTG activates the expression of p53 and modulates its function, with this action of PTTG being mediated through the regulation of c-myc expression. PTTG also up-regulates the activity of the bax promoter and increases the expression of bax through modulation of p53 expression

Conceptos erróneos comunes sobre COVID-19 entre los profesionales de la salud: una encuesta transversal global en línea.

Background: The COVID-19 pandemic has taken the world by storm, with cases continuously increasing by the hour and with a shortage of information regarding the virus available to the general public. Despite the availability of trusted online sources, there are still misconceptions relating to the virus floating around. This study aimed to find out the level of misconceptions among healthcare professionals (HCPs) worldwide about the ensuing COVID-19 pandemic. Materials and Methods: A descriptive cross sectional study was conducted through a global online survey. The self-administered questionnaire was designed and registered at an online website (Kwiksurveys). A total of 652 participants from 35 different countries across the world responded. Statistical analysis was performed using SPSS version 23. Socio-demographic and discipline characteristics were compared with the help of the chi-square test and univariate and multivariate logistic regression to find significant relationships. Results: Among all HCPs, general physicians (61.2%) were the most common respondents. The responses from females (63.3%) almost doubled those of men, and nearly half of the participants were working in private institutes (49.2%). Additionally, the major source of information used by HCPs about COVID-19 was social media (55.4%). Regarding misconception assessment, 71.6% of participants had correct concepts regarding COVID-19. However, 28.4% had incorrect information. Female HCPs were 1.49 times more likely to have correct concepts compared to males (OR=1.49, 95% CI=1.04-2.14). Conclusions: The majority of the HCPs were keeping themselves up-to-date with current information concerning the knowledge, prevention, and hygiene practices of COVID-19 infection. However, some misconceptions are deeply rooted in the mindsets of HCPs worldwide and need to be addressed by the continuous professional development of HCPs. The availability of reliable sources of information on the pandemic should be encouraged, with adequate explanations also available to the general public in simple terms.Antecedentes: la pandemia de COVID-19 ha asolado al mundo, con casos que aumentan continuamente  y con una escasez de información sobre el virus disponible para el público en general. A pesar de la disponibilidad de fuentes confiables en línea, todavía hay conceptos erróneos relacionados con el virus. Este estudio tuvo como objetivo dilucidar el nivel de ideas erróneas entre los profesionales de la salud (PS) en todo el mundo sobre la pandemia de COVID-19. Material y Métodos: Se realizó un estudio descriptivo de corte transversal a través de una encuesta global en línea. El cuestionario autoadministrado fue diseñado y registrado en un sitio web en línea (Kwiksurveys). Respondieron un total de 652 participantes de 35 países. El análisis estadístico se realizó con el programa SPSS versión 23. Las características sociodemográficas y disciplinarias se compararon con la ayuda de la la prueba de chi-cuadrado y la regresión logística univariada y multivariada para encontrar relaciones significativas. Resultado: Entre todos los profesionales de la salud, los médicos generales (61,2%) fueron los que más respondieron. Las respuestas de las mujeres (63,3%) casi duplicaron las de los hombres, y casi la mitad de los participantes trabajaban en institutos privados (49,2%). Además, la principal fuente de información utilizada por los profesionales de la salud sobre COVID-19 fueron las redes sociales (55,4%). En cuanto a los conceptos erróneos, el 71,6% de los participantes tenían conceptos correctos con respecto a COVID-19. Sin embargo, el 28.4% poseía información incorrecta. Los profesionales de la salud mujeres tenían 1.49 veces más probabilidades de tener conceptos correctos en comparación con los hombres (OR = 1.49, IC 95% = 1.04-2.14). Conclusion: La mayoría de los profesionales de la salud se mantuvieron actualizados con la información actual sobre el conocimiento, la prevención y las prácticas de higiene de la infección por COVID-19. Sin embargo, algunos conceptos erróneos están profundamente arraigados en la mentalidad de los PS en todo el mundoy deben abordarse mediante el continuo desarrollo profesional de los PS. Se debe alentar la disponibilidad de fuentes confiables de información sobre la pandemia, con explicaciones adecuadas también disponibles para el público en general en términos simples

Ectopic expression of PTTG1/securin promotes tumorigenesis in human embryonic kidney cells

BACKGROUND: Pituitary tumor transforming gene1 (PTTG1) is a novel oncogene that is expressed in most tumors. It encodes a protein that is primarily involved in the regulation of sister chromatid separation during cell division. The oncogenic potential of PTTG1 has been well characterized in the mouse, particularly mouse fibroblast (NIH3T3) cells, in which it induces cell proliferation, promotes tumor formation and angiogenesis. Human tumorigenesis is a complex and a multistep process often requiring concordant expression of a number of genes. Also due to differences between rodent and human cell biology it is difficult to extrapolate results from mouse models to humans. To determine if PTTG1 functions similarly as an oncogene in humans, we have characterized its effects on human embryonic kidney (HEK293) cells. RESULTS: We report that introduction of human PTTG1 into HEK293 cells through transfection with PTTG1 cDNA resulted in increased cell proliferation, anchorage-independent growth in soft agar, and formation of tumors after subcutaneous injection of nu/nu mice. Pathologic analysis revealed that these tumors were poorly differentiated. Both analysis of HEK293 cells transiently transfected with PTTG1 cDNA and analysis of tumors developed on injection of HEK293 cells that had been stably transfected with PTTG1 cDNA indicated significantly higher levels of secretion and expression of bFGF, VEGF and IL-8 compared to HEK293 cells transfected with pcDNA3.1 vector or uninvolved tissues collected from the mice. Mutation of the proline-rich motifs at the C-terminal of PTTG1 abolished its oncogenic properties. Mice injected with this mutated PTTG1 either did not form tumors or formed very small tumors. Taken together our results suggest that PTTG1 is a human oncogene that possesses the ability to promote tumorigenesis in human cells at least in part through the regulation of expression or secretion of bFGF, VEGF and IL-8. CONCLUSIONS: Our results demonstrate that PTTG1 is a potent human oncogene and has the ability to induce cellular transformation of human cells. Overexpression of PTTG1 in HEK293 cells leads to an increase in the secretion and expression of bFGF, VEGF and IL-8. Mutation of C-terminal proline-rich motifs abrogates the oncogenic function of PTTG1. To our knowledge, this is the first study demonstrating the importance of PTTG1 in human tumorigenesis

Prevalence of cervical ribs and elongated transverse processes in Kashmiri population

Background: The aim of this study was to describe the prevalence of cervical ribs and elongated transverse process in the Kashmiri population.Methods: We reviewed 2000 chest x rays of adult patients which were done in a period of 4 months in the department of Radiology, Govt Medical College Hospital, Srinagar, J& K.Results: The diagnosis of cervical rib was made in a total of 50 radiographs with a prevalence of 2.67%. The prevalence of cervical rib was higher in females (3.1%) as compared to males (2.1%). A total of 67 cervical ribs were seen in 50 patients. Unilateral cervical rib was seen in 33(66.0%) patients, right sided in 20(40.0%) and left sided in 13(26.0%). Bilateral cervical ribs were seen in 17(34.0%) patients. Elongated transverse process was seen in 280 patients constituting a prevalence of 14.96%. The prevalence in females (17.95%) was higher than males (12.15%).Conclusions: Prevalence of cervical rib and C7 transversomegaly is high in Kashmiri population. Similar results have been noted in Saudi population. Thus it is concluded that in the populations with higher rates of consanguinity, there is high probability of occurrence of cervical ribs because of HOX gene mutations. There is need for many more well designed studies to prove this association. Keeping in mind the high prevalence of cervical rib, patients with unexplained cervical pain need to be evaluated for this entity.

Does surgeon experience influence the amount of radiation exposure during orthopedic procedures?: A systematic review

With an increasing use of intraoperative fluoroscopy in operating rooms worldwide, the topic of radiation exposure has become a major concern among hospital staff, doctors and patients alike. Since fluoroscopy has become an integral part in orthopedic intraoperative management, we sought to identify whether surgeon grade or experience plays a role in the amount of radiation used and consequently exposed. We performed a systematic review examining the association between surgeon experience and radiation exposure using primary outcome measures (radiation dose and total screening time/fluoroscopy time). To be included in the review, the study population had to compare varying surgeon experience levels and their effect on the primary outcomes. A total of eighteen studies were included in the review. The studies were a mix of prospective and retrospective studies with low to moderate quality as evaluated by the MINORs criteria. Studies were variable in defining surgeon experience levels and in the type of operations being performed. Majority of the studies showed that inexperienced surgeons/trainees had a higher total fluoroscopy time and a higher mean radiation exposure as compared to experienced surgeons. We conclude that higher surgeon experience significantly reduces usage of fluoroscopy and the consequent radiation exposure in orthopedic procedures. Introduction of strict radiation guidelines involving limited usage of fluoroscopy and supervision of trainees may be beneficial in controlling radiation exposure in the future

Antibacterial Activity of Carvacrol against Different Types of Bacteria

In the present study, antibacterial efficiency of Carvacrol was studied on nine types of pathogenic bacteria isolated from different clinical samples, S. aureus, S. epidermidis, St. pneumonia? , E. coli, Klebsiella pneumonia, Proteus mirabilis, Pseudomonas aeroginosa,  Enterobacter spp. and Serratia spp. the inhibitory effects of this oil were compared with standard antibiotics, ciprofloxacin. The inhibition effect of Carvacrol in different concentration of bacterial growth were studied, the results showed that there is a great inhibition growth on all studied bacterial isolates except Pseudomonas aeroginosa. Keywords: Carvacrol, Antibacterial, Thymus, Vulgaris, Ciprofloxacin

Analysis of Unsteady Axisymmetric Squeezing Fluid Flow with Slip and No-Slip Boundaries Using OHAM

In this manuscript, An unsteady axisymmetric flow of nonconducting, Newtonian fluid squeezed between two circular plates is studied with slip and no-slip boundaries. Using similarity transformation, the system of nonlinear partial differential equations is reduced to a single fourth order ordinary differential equation. The resulting boundary value problems are solved by optimal homotopy asymptotic method (OHAM) and fourth order explicit Runge-Kutta method (RK4). It is observed that the results obtained from OHAM are in good agreement with numerical results by means of residuals. Furthermore, the effects of various dimensionless parameters on the velocity profiles are investigated graphically

A Methodology to Measure СP / CV Ratio Using U-shape Acoustic Resonance Tube

The specific heat ratio of gases can be determined using several measuring instruments. Recently acoustic resonance instruments have shown great versatility and are used in various branches of industrial applications. This article proposes a simple measurement methodology to measure the specific heat ratio i.e., Сp / Cv using a free mode of acoustic resonance within a U-shape resonator. The specific heat ratio is calculated by measuring the speed of sound in a tube filled by the sample of the gas under test. For this purpose, the signal of standing wave is acquired using a sound card of Personal Computer. The received signal is rocessed by LabVIEW software. The experimental results show that the measured value of the specific heat ratio of several types of gases can be calculated using the proposed methodology and the relative error is about 2%

Contegra valved conduit in the paediatric population: an exciting prospect for right ventricle to pulmonary artery reconstruction; experience and outcomes at Aga Khan University

Objective: The focus of this study is to share the experience and outcomes of Contegra graft implantation in the paediatric and adult population in Pakistan. Methods: Between May 2007 and July 2011, 16 patients, underwent implantation of a Contegra valved conduit. All operations were performed through a median sternotomy with cardiopulmonary bypass. Indications included: Pulmonary atresia with ventricular septal defect (n=11), Tetralogy of Fallot with absent Pulmonary Valve (PV) syndrome (n=2), double outlet right ventricle, transposition of great arteries and pulmonary stenosis (n=1), isolated aortic valve disease (n=1) and a pseudo-aneurysm with infective endocarditis (n=1).Conduit sizes varied between 16-22 mm. Results: The three in hospital deaths were unrelated to the Contegra valved conduit. One patient was lost to follow up. Of the 12 survivors, 10 are currently free from re-operation or complications related to the conduit while one needed distal pulmonary artery dilatation owing to critical stenosis and another had severe Valvular regurgitation. Echocardiographic evaluation of the Contegra valved conduit demonstrated no haemodynamically significant valve regurgitation in 10 patients. Conclusion: In this small review of 16 operations using the Contegra valved conduit for Right Venticular Outflow Tract (RVOT) reconstruction in the paediatric population, we observed good post operative results concerning conduit function. The Contegra conduit provides an excellent substitute to the homograft with satisfactory early and mid-term results though long term results are awaited in Pakista