Centrifuge modelling of the initiation of cracks in a clay liner subjected to differential settlement with and without overburden pressure

Compacted clay liners are used in the basal and capping layers of landfills to separate the waste material from the environment. These liners are subjected to differential settlement through degradation of the waste or compression of the subgrade. This differential settlement induces cracking in the liner, and reduces the effectiveness of the clay as an en vironmental protection barrier. P hysical model tests were conducted in the geotechnical centrifuge to study the influence of differential settlement on clay liners and observe the crack mechanism using a consolidated kaolin clay beam to model the clay liner . Differential settlement was imposed on the clay beam by means of a trapdoor. Cracking in the clay was monitored through digital analysis of images taken as the tests were conducted using particle image velocimetry. The test investigate d the orientation and types of cracks formed with varying void dimensions and with and without overburden pressure The unconfined clay over the small trapdoor was able to support itself across the void; a punching shear failure occurred in the case of a wider trapdoor or greater overburden pressure

Pediatric carcinoma of rectum - Varanasi experience

Background : Primary gastrointestinal system malignancies constitute approximately 2% of pediatric neoplasm and of these; colorectal carcinoma is the second most common malignancy. This is one of the rarer diseases in children. Aim : We reviewed our records to study the clinical features, outcome and the follow-up of this condition with evaluation of the prognostic factors. Settings and Design: Tertiary care Pediatric Surgery centre. Retrospective study. Materials and Methods : The data of all patients with diagnosis of colorectal carcinoma from January 1986 to January 2006 were reviewed. The confirmation of the diagnosis was by biopsy from the lesion. The age, sex, family history, clinical features, response to the treatment and follow-up were studied. Results : There were four male patients. All had bleeding per rectum as the presenting complaint. Three patients had advanced disease at presentation. All the patients had signet cell adenocarcinoma. The two patients expired and one was lost to follow-up. One patient is alive after one year of follow up and is receiving treatment. Conclusion : Colorectal cancer in children though rare can be a reality, hence any children presenting with pain in abdomen along with doubtful history of constipation and rectal bleeding should be examined carefully with special emphasis on digital rectal examination

Single-Stage Repair versus Traditional Repair of High Anorectal Malformations, Functional Results’ Correlation with Kelly’s Score and Postoperative Magnetic Resonance Imaging Findings

Introduction: Posterior sagittal anorectoplasty (PSARP) is the standard treatment for anorectal malformations. In the present study, the clinical evaluation of anal continence was carried out using Kelly’s scoring system and the results of primary PSARP or abdomino-PSARP were compared with the traditional three-stage procedure and the functional outcome was correlated with the findings of MRI, which was used as an objective method of evaluation.Patients and methods: A total of 40 patients with intermediate and high anorectal malformations were studied and were divided into two groups on the basis of a random number table. The patients in group A were treated with a single-stage operation, whereas the patients in group B were treated with a standard staged operation (either PSARP or abdominoperineal pull-through). After clinical evaluation using the Kelly score, patients were divided into three clinical groups irrespective of whether they were operated in one stage or in three stages. All patients were subjected to MRI at the age of 3 years and the findings were correlated with the clinical scoring system.Result: Patients were categorized according to their Kelly’s scores as follows: group 1: clinically good (score 5–6); group 2: clinically fair (score 3–4); and group 3: clinically poor (score 0–2). The proportions of good development of the muscles (puborectalis, external sphincter muscle, and levator muscle hammock) were 78.9% in group 1, 40% in group 2, and none in group 3. Development of muscles was found to be a significant factor for anal continence. Other significant factors for anal continence are rectal diameter and anorectal angle.Conclusion: Clinical assessment using the Kelly score was similar for the single-stage operation and the staged procedure, and this was supported by MRI findings. Therefore, we recommend the single-stage procedure to achieve a better outcome in intermediate and high anorectal malformation.Keywords: Anorectal Malformations, MRI, Posterior Sagittal Anorectoplast

Pediatric carcinoma of rectum - Varanasi experience

Background : Primary gastrointestinal system malignancies constitute approximately 2% of pediatric neoplasm and of these; colorectal carcinoma is the second most common malignancy. This is one of the rarer diseases in children. Aim : We reviewed our records to study the clinical features, outcome and the follow-up of this condition with evaluation of the prognostic factors. Settings and Design: Tertiary care Pediatric Surgery centre. Retrospective study. Materials and Methods : The data of all patients with diagnosis of colorectal carcinoma from January 1986 to January 2006 were reviewed. The confirmation of the diagnosis was by biopsy from the lesion. The age, sex, family history, clinical features, response to the treatment and follow-up were studied. Results : There were four male patients. All had bleeding per rectum as the presenting complaint. Three patients had advanced disease at presentation. All the patients had signet cell adenocarcinoma. The two patients expired and one was lost to follow-up. One patient is alive after one year of follow up and is receiving treatment. Conclusion : Colorectal cancer in children though rare can be a reality, hence any children presenting with pain in abdomen along with doubtful history of constipation and rectal bleeding should be examined carefully with special emphasis on digital rectal examination

Regulation of Mouse Small Heat Shock Protein αb-Crystallin Gene by Aryl Hydrocarbon Receptor

The stress-inducible small heat shock protein (shsp)/αB-crystallin gene is expressed highly in the lens and moderately in other tissues. Here we provide evidence that it is a target gene of the aryl hydrocarbon receptor (AhR) transcription factor. A sequence (−329/−323, CATGCGA) similar to the consensus xenobiotic responsive element (XRE), called here XRE-like, is present in the αBE2 region of αB-crystallin enhancer and can bind AhR in vitro and in vivo. αB-crystallin protein levels were reduced in retina, lens, cornea, heart, skeletal muscle and cultured muscle fibroblasts of AhR−/− mice; αB-crystallin mRNA levels were reduced in the eye, heart and skeletal muscle of AhR−/− mice. Increased AhR stimulated αB-crystallin expression in transfection experiments conducted in conjunction with the aryl hydrocarbon receptor nuclear translocator (ARNT) and decreased AhR reduced αB-crystallin expression. AhR effect on aB-crystallin promoter activity was cell-dependent in transfection experiments. AhR up-regulated αB-crystallin promoter activity in transfected HeLa, NIH3T3 and COS-7 cells in the absence of exogenously added ligand (TCDD), but had no effect on the αB-crystallin promoter in C2C12, CV-1 or Hepa-1 cells with or without TCDD. TCDD enhanced AhR-stimulated αB-crystallin promoter activity in transfected αTN4 cells. AhR could bind to an XRE-like site in the αB-crystallin enhancer in vitro and in vivo. Finally, site-specific mutagenesis experiments showed that the XRE-like motif was necessary for both basal and maximal AhR-induction of αB-crystallin promoter activity. Our data strongly suggest that AhR is a regulator of αB-crystallin gene expression and provide new avenues of research for the mechanism of tissue-specific αB-crystallin gene regulation under normal and physiologically stressed conditions

Artificial Neural Network Inference (ANNI): A Study on Gene-Gene Interaction for Biomarkers in Childhood Sarcomas

Objective: To model the potential interaction between previously identified biomarkers in children sarcomas using artificial neural network inference (ANNI). Method: To concisely demonstrate the biological interactions between correlated genes in an interaction network map, only 2 types of sarcomas in the children small round blue cell tumors (SRBCTs) dataset are discussed in this paper. A backpropagation neural network was used to model the potential interaction between genes. The prediction weights and signal directions were used to model the strengths of the interaction signals and the direction of the interaction link between genes. The ANN model was validated using Monte Carlo cross-validation to minimize the risk of over-fitting and to optimize generalization ability of the model. Results: Strong connection links on certain genes (TNNT1 and FNDC5 in rhabdomyosarcoma (RMS); FCGRT and OLFM1 in Ewing’s sarcoma (EWS)) suggested their potency as central hubs in the interconnection of genes with different functionalities. The results showed that the RMS patients in this dataset are likely to be congenital and at low risk of cardiomyopathy development. The EWS patients are likely to be complicated by EWS-FLI fusion and deficiency in various signaling pathways, including Wnt, Fas/Rho and intracellular oxygen. Conclusions: The ANN network inference approach and the examination of identified genes in the published literature within the context of the disease highlights the substantial influence of certain genes in sarcomas

The AFLOW Fleet for Materials Discovery

The traditional paradigm for materials discovery has been recently expanded to incorporate substantial data driven research. With the intent to accelerate the development and the deployment of new technologies, the AFLOW Fleet for computational materials design automates high-throughput first principles calculations, and provides tools for data verification and dissemination for a broad community of users. AFLOW incorporates different computational modules to robustly determine thermodynamic stability, electronic band structures, vibrational dispersions, thermo-mechanical properties and more. The AFLOW data repository is publicly accessible online at aflow.org, with more than 1.7 million materials entries and a panoply of queryable computed properties. Tools to programmatically search and process the data, as well as to perform online machine learning predictions, are also available.Comment: 14 pages, 8 figure

Parameters influencing the size of chitosan-TPP nano- and microparticles

Chitosan nanoparticles, produced by ionic gelation, are among the most intensely studied nanosystems for drug delivery. However, a lack of inter-laboratory reproducibility and a poor physicochemical understanding of the process of particle formation have been slowing their potential market applications. To address these shortcomings, the current study presents a systematic analysis of the main polymer factors affecting the nanoparticle formation driven by an initial screening using systematic statistical Design of Experiments (DoE). In summary, we found that for a given chitosan to TPP molar ratio, the average hydrodynamic diameter of the particles formed is strongly dependent on the initial chitosan concentration. The degree of acetylation of the chitosan was found to be the second most important factor involved in the system's ability to form particles. Interestingly, viscosimetry studies indicated that the particle formation and the average hydrodynamic diameter of the particles formed were highly dependent on the presence or absence of salts in the medium. In conclusion, we found that by controlling two simple factors of the polymer solution, namely its initial concentration and its solvent environment, it is feasible to control in a reproducible manner the production and characteristics of chitosan particles ranging in size from nano- to micrometres

Cerebral activations related to ballistic, stepwise interrupted and gradually modulated movements in parkinson patients

Patients with Parkinson's disease (PD) experience impaired initiation and inhibition of movements such as difficulty to start/stop walking. At single-joint level this is accompanied by reduced inhibition of antagonist muscle activity. While normal basal ganglia (BG) contributions to motor control include selecting appropriate muscles by inhibiting others, it is unclear how PD-related changes in BG function cause impaired movement initiation and inhibition at single-joint level. To further elucidate these changes we studied 4 right-hand movement tasks with fMRI, by dissociating activations related to abrupt movement initiation, inhibition and gradual movement modulation. Initiation and inhibition were inferred from ballistic and stepwise interrupted movement, respectively, while smooth wrist circumduction enabled the assessment of gradually modulated movement. Task-related activations were compared between PD patients (N = 12) and healthy subjects (N = 18). In healthy subjects, movement initiation was characterized by antero-ventral striatum, substantia nigra (SN) and premotor activations while inhibition was dominated by subthalamic nucleus (STN) and pallidal activations, in line with the known role of these areas in simple movement. Gradual movement mainly involved antero-dorsal putamen and pallidum. Compared to healthy subjects, patients showed reduced striatal/SN and increased pallidal activation for initiation, whereas for inhibition STN activation was reduced and striatal-thalamo-cortical activation increased. For gradual movement patients showed reduced pallidal and increased thalamo-cortical activation. We conclude that PD-related changes during movement initiation fit the (rather static) model of alterations in direct and indirect BG pathways. Reduced STN activation and regional cortical increased activation in PD during inhibition and gradual movement modulation are better explained by a dynamic model that also takes into account enhanced responsiveness to external stimuli in this disease and the effects of hyper-fluctuating cortical inputs to the striatum and STN in particular