Region Convolutional Neural Network for Brain Tumor Segmentation.

Gliomas are often difficult to find and distinguish using typical manual segmentation approaches because of their vast range of changes in size, shape, and appearance. Furthermore, the manual annotation of cancer tissue segmentation under the close supervision of a human professional is both time-consuming and exhausting to perform. It will be easier and faster in the future to get accurate and quick diagnoses and treatments thanks to automated segmentation and survival rate prediction models that can be used now. In this article, a segmentation model is designed using RCNN that enables automatic prognosis on brain tumors using MRI. The study adopts a U-Net encoder for capturing the features during the training of the model. The feature extraction extracts geometric features for the estimation of tumor size. It is seen that the shape, location, and size of a tumor are significant factors in the estimation of prognosis. The experimental methods are conducted to test the efficacy of the model, and the results of the simulation show that the proposed method achieves a reduced error rate with increased accuracy than other methods.

Roles and responsibilities in newborn care in four African sites.

OBJECTIVES: To explore roles and responsibilities in newborn care in the intra- and postpartum period in Nigeria, Tanzania and Ethiopia. METHODS: Qualitative data were collected using in-depth interviews with mothers, grandmothers, fathers, health workers and birth attendants and were analysed through content and framework analyses. RESULTS: We found that birth attendants were the main decision-makers and care takers in the intrapartum period. Birth attendants varied across sites and included female relatives (Ethiopia and Nigeria), traditional birth attendants (Tanzania and Nigeria), spiritual birth attendants (Nigeria) and health workers (Tanzania and Nigeria). In the early newborn period, when the mother is deemed to be resting, female family members assumed this role. The mothers themselves only took full responsibility for newborn care after a few days or weeks. The early newborn period was protracted for first-time mothers, who were perceived as needing training on caring for the baby. Clear gender roles were described, with newborn care being considered a woman's domain. Fathers had little physical contact with the newborn, but played an important role in financing newborn care, and were considered the ultimate decision-maker in the family. CONCLUSION: Interventions should move beyond a focus on the mother-child dyad, to include other carers who perform and decide on newborn care practices. Given this power dynamic, interventions that involve men have the potential to result in behaviour change.

Distinct phosphorylation sites in the SST2A somatostatin receptor control internalization, desensitization, and arrestin binding.

The somatostatin subtype 2A (sst2A) receptor, a member of the G protein-coupled receptor superfamily, mediates many of the neuroendocrine and neuromodulatory actions of somatostatin, and it represents the primary target for somatostatin analogs used in cancer therapy and tumor localization. Agonist stimulation leads to the rapid phosphorylation, endocytosis, and desensitization of the sst2A receptor; however, little is known about the role of phosphorylation in sst2A regulation. sst2A phosphorylation occurs on serine and threonine residues in the third intracellular loop and carboxyl terminus. Therefore, we generated mutant receptors in which serine (Ser-), threonine (Thr-), or both (Ser-/Thr-) residues in these regions were mutated to alanine. In contrast to the wild-type receptor, somatostatin treatment did not stimulate the phosphorylation of the Ser-/Thr- mutant, and it did not produce desensitization. Furthermore, internalization of the Ser-/Thr- mutant occurred 5 times more slowly than with the wild-type receptor. Mutating only the Ser residues did not inhibit either internalization or desensitization. In contrast, mutating only the Thr residues inhibited receptor endocytosis to the same extent as in the full mutant, but it did not affect receptor desensitization. In both the wild-type and Ser- receptors, agonist binding produced a stable arrestin-receptor complex that was maintained during receptor trafficking, whereas arrestin was not recruited to either the Thr- or the Ser-/Thr- receptors. These results demonstrate that agonist-stimulated receptor phosphorylation is necessary for both desensitization and rapid internalization of the sst2A receptor. However, sst2A receptor internalization and uncoupling can occur independently, involve different receptor phosphorylation sites, and exhibit different requirements for stable arrestin association.

Phenotypic classification of mutants: a tool for understanding ligand binding and activation of muscarinic acetylcholine receptors.

GPCRs (G-protein-coupled receptors) such as the M(1) muscarinic receptor have so far proved recalcitrant to direct structure determination. Nevertheless systematic mutagenesis, particularly alanine scanning, has advanced our understanding of their structure-function relationships. GPCRs exhibit multiple conformational states with different affinities for and abilities to activate their cognate G-proteins. Ligand binding alters these conformational equilibria, thus promoting or inhibiting signalling. Alanine-scanning mutagenesis probes the relative contributions of a particular amino acid side chain to the stability of the ground and activated states of the receptor and its complexes. These determine the phenotype of the mutant receptor. Classification of the phenotypes suggests functional roles for particular amino acid side chains, allowing us to group them accordingly. From a rhodopsin-based homology model of the M(1) mAChR, a coherent view emerges of how these clusters of residues function in ligand anchoring, transduction of binding energy, global structural stabilization and selective stabilization of the ground state or the activated state of the receptor. We can identify differences in ligand-binding modes, and suggest inter- and intra-molecular interactions that are weakened or broken, or formed or intensified during acetylcholine-induced activation. In due course, we may be able to extend these insights to activation by unconventional agonists.

Scanning mutagenesis studies of the M1 muscarinic acetylcholine receptor.

Following the solution of the structure of bovine rhodopsin by X-ray crystallography, it has been possible to build an improved homology model of the M(1) muscarinic acetylcholine receptor. This has been used to interpret the outcome of an extensive series of scanning and point mutagenesis studies on the transmembrane domain of the receptor. Potential intramolecular interactions enhancing the stability of the protein fold have been identified. The residues contributing to the binding site for the antagonist, N-methylscopolamine, and the agonist, acetylcholine have been mapped. The positively charged headgroups of these ligands appear to bind in a charge-stabilized aromatic cage formed by amino acid side chains in transmembrane (TM) helices 3, 6, and 7, while residues in TM 4 may participate in a peripheral docking site. Closure of the cage around the headgroup of acetylcholine may help to transduce binding energy into receptor activation, possibly disrupting a set of Van der Waals interactions between a set of residues underlying the binding site which help to constrain the receptor to the inactive state, in the absence of agonist. This may trigger the reorganization of a hydrogen bonding network between highly conserved residues in the core of the receptor, whose integrity is crucial for activation.

Structure and activation of muscarinic acetylcholine receptors.

A homology model of the M(1) muscarinic acetylcholine receptor, based on the X-ray structure of bovine rhodopsin, has been used to interpret the results of scanning and point mutagenesis studies on the receptor's transmembrane (TM) domain. Potential intramolecular interactions that are important for the stability of the protein fold have been identified. The residues contributing to the binding site for the antagonist, N -methyl scopolamine, and the agonist, acetylcholine, have been mapped. The positively charged headgroups of these ligands probably bind in a charge-stabilized aromatic cage formed by amino acid side chains in TM helices TM3, TM6 and TM7, while residues in TM4 may participate as part of a peripheral docking site. Closure of the cage around the headgroup of acetylcholine may be part of the mechanism for transducing binding energy into receptor activation, probably by disrupting a set of Van der Waals interactions between residues lying beneath the binding site that help to constrain the receptor to the inactive state, in the absence of agonist. This may trigger the reorganization of a hydrogen-bonding network between highly conserved residues in the core of the receptor, whose integrity is crucial for achievement of the activated state.

Habituation and sensitization of aggression in bullfrogs (Rana catesbeiana): testing the dual-process theory of habituation.

The aggressive response of male bullfrogs (Rana catesbeiana) habituates with repeated broadcasts of acoustic stimuli simulating a new territorial neighbor. The effects of stimulus repetition rate and stimulus intensity on bullfrog aggressive responses were tested in a field experiment designed to test the assumptions of a dual-process theory of habituation. Synthetic advertisement calls were broadcast at 2 repetition rates and 2 intensities in a factorial design. Bullfrogs were more aggressive at the higher stimulus intensity at both repetition rates. Aggressive responses habituated more slowly at the higher stimulus intensity and slower repetition rate compared with other treatments. Several biotic and abiotic factors had small or negligible effects on aggressive responses. Although consistent with the operation of 2 opposing processes, habituation and sensitization, the data provide only partial support for the assumptions of dual-process theory.

The conformational switch in muscarinic acetylcholine receptors.

The recently-determined structure of rhodopsin has provided a suitable basis for modeling the three-dimensional structure of the M1 muscarinic acetylcholine receptor. Using this as a framework for interpreting mutagenesis studies, we have been able to suggest most of the contacts which the receptor makes with acetylcholine and many of the intramolecular contacts which are important for the ground-state structure of the receptor. It is possible to outline a mechanism of G-protein interaction.

Habituation as a mechanism of reduced aggression between neighboring territorial male bullfrogs (Rana catesbeiana).

Territorial animals often exhibit relatively lower levels of aggression toward familiar territorial neighbors than toward strangers. Habituation to a neighbor or its communication signals has been proposed to account for this reduced aggression between adjacent territorial neighbors. The authors asked whether discrimination between neighbors and strangers by territorial male bullfrogs (Rana catesbeiana) could result from habituation of the aggressive response to repeated presentations of the acoustic communication signals of a simulated new neighbor calling from an adjacent territory. In 3 field playback experiments, the authors found evidence for 5 response characteristics that operationally define habituation. Moreover, aggressive response decrements persisted between nights of chorusing and were specific to an individually distinct property of male advertisement calls. The authors suggest that reduced aggression between neighboring territorial male bullfrogs could result from long-term, stimulus-specific habituation to the advertisement calls of a new neighbor.

Molecular approach to the interpretation of the dielectric relaxation spectrum of a molecular glass former

The frequency-dependent dielectric function of ethanol at temperatures within the normal liquid range is evaluated by means of computer molecular dynamics simulations and compared with recent experimental data. The calculated spectra show a similar structure to those reported from experimental measurements and the temperature dependence of its most prominent bands also follows the experimental estimates. An attempt is also made to assign the most intense bands to specific molecular reorientations.

Prevalence of overweight and obese school children aged between 7 to 16 years amongst the major 3 ethnic groups in Kuala Lumpur, Malaysia.

6239 children aged 7 to 16 years, attending 22 primary and secondary schools in Kuala Lumpur, Malaysia, were screened using a self report questionnaire, with their heights and weights measured using a digital electronic SECA beam balance. The selection was done by a two staged stratified random sampling from a total of 226 schools in Kuala Lumpur. The racial distribution was 56.7% Malays, 33.8% Chinese and 8.1% Indians; 3.6% (n:222) of the children were identified as obese and 6% (n:373) identified as overweight. The definitions of obese and overweight were computed using growth charts of the National Centre for Health Statistics (NCHS) from the median of the reference population. There were no significant differences amongst the 3 major ethnic groups in the obese group. The differences were significant in the overweight group with the Indians most overweight, followed by the Chinese and the Malays.

Fish stings and other marine envenomations.

West Virginia, it would seem, is an unlikely place for physicians to encounter patients with poisonous marine envenomations. To the contrary, West Virginias who vacation at the beach may be envenomated and require further evaluation and treatment when they return home. Likewise, certain aquarium pets or even freshwater fish may envenomate those who have contact with them. Such underwater sea creatures can cause local and systemic toxic or allergic reactions which potentially can be serious. This article describes these possible toxic encounters as well as first aid and medical management.