ConnectViz: Accelerated approach for brain structural connectivity using Delaunay triangulation

Stroke is a cardiovascular disease with high mortality and long-term disability in the world. Normal functioning of the brain is dependent on the adequate supply of oxygen and nutrients to the brain complex network through the blood vessels. Stroke, occasionally a hemorrhagic stroke, ischemia or other blood vessel dysfunctions can affect patients during a cerebrovascular incident. Structurally, the left and the right carotid arteries, and the right and the left vertebral arteries are responsible for supplying blood to the brain, scalp and the face. However, a number of impairment in the function of the frontal lobes may occur as a result of any decrease in the flow of the blood through one of the internal carotid arteries. Such impairment commonly results in numbness, weakness or paralysis. Recently, the concepts of brain's wiring representation, the connectome, was introduced. However, construction and visualization of such brain network requires tremendous computation. Consequently, previously proposed approaches have been identified with common problems of high memory consumption and slow execution. Furthermore, interactivity in the previously proposed frameworks for brain network is also an outstanding issue. This study proposes an accelerated approach for brain connectomic visualization based on graph theory paradigm using Compute Unified Device Architecture (CUDA), extending the previously proposed SurLens Visualization and Computer Aided Hepatocellular Carcinoma (CAHECA) frameworks. The accelerated brain structural connectivity framework was evaluated with stripped brain datasets from the Department of Surgery, University of North Carolina, Chapel Hill, United States. Significantly, our proposed framework is able to generates and extracts points and edges of datasets, displays nodes and edges in the datasets in form of a network and clearly maps data volume to the corresponding brain surface. Moreover, with the framework, surfaces of the dataset were simultaneously displayed with the nodes and the edges. The framework is very efficient in providing greater interactivity as a way of representing the nodes and the edges intuitively, all achieved at a considerably interactive speed for instantaneous mapping of the datasets' features. Uniquely, the connectomic algorithm performed remarkably fast with normal hardware requirement specifications.

A preliminary report on ants (Hymenoptera: Formicidae) recovered from forensic entomological studies conducted in different ecological habitats in Malaysia

This study reported the ant species that were recovered from monkey carcasses in three different ecological habitats in Malaysia. The study was conducted from 9 May - 10 October 2007, 6 May - 6 August 2008 and 26 May - 14 July 2009 in forested area (Gombak, Selangor), coastal area (Tanjong Sepat, Selangor) and highland area (Bukit Cincin, Pahang), respectively. Monkey carcass was used as a model for human decomposition in this study. A total of 4 replicates were used in each of the study sites. Ants were observed to prey on eggs, larvae, pupae and newly emerged flies. This study found that ant species could be found at all stages of decomposition, indicating that ants were not a significant indicator for faunal succession. However, different species of ants were obtained from monkey carcasses placed in different ecological habitats. Cardiocondyla sp. was only found on carcasses placed in the coastal area; while Pheidole longipes, Hypoponera sp. and Pachycondyla sp. were solely found on carcasses placed in the highland area. On the other hand, Pheidologeton diversus and Paratrechina longicornis were found in several ecological habitats. These data suggests that specific ant species can act as geographic indicators for different ecological habitats in forensic entomology cases in Malaysia.

Utility of DNA barcoding for rapid and accurate assessment of bat diversity in Malaysia in the absence of formally described species

Bats are important flagship species for biodiversity research; however, diversity in Southeast Asia is considerably underestimated in the current checklists and field guides. Incorporation of DNA barcoding into surveys has revealed numerous species-level taxa overlooked by conventional methods. Inclusion of these taxa in inventories provides a more informative record of diversity, but is problematic as these species lack formal description. We investigated how frequently documented, but undescribed, bat taxa are encountered in Peninsular Malaysia. We discuss whether a barcode library provides a means of recognizing and recording these taxa across biodiversity inventories. Tissue was sampled from bats trapped at Pasir Raja, Dungun Terengganu, Peninsular Malaysia. The DNA was extracted and the COI barcode region amplified and sequenced. We identified 9 species-level taxa within our samples, based on analysis of the DNA barcodes. Six specimens matched to four previously documented taxa considered candidate species but currently lacking formal taxonomic status. This study confirms the high diversity of bats within Peninsular Malaysia (9 species in 13 samples) and demonstrates how DNA barcoding allows for inventory and documentation of known taxa lacking formal taxonomic status.

Child physical abuse: assessment of dental students' attitudes and knowledge in United Arab Emirates

AIM

To investigate dental students' educational experience, attitudes and knowledge with regard to child physical abuse in all dental schools in United Arab Emirates.

METHODS

The data were collected by self-administered structured questionnaire completed by 578 under graduate dental students in four (all) dental schools in United Arab Emirates. Data were analysed using descriptive analyses for responses to each question.

RESULTS

The results indicated that there was lack of knowledge of reporting procedure, signs of physical abuse and social indicators among all respondents. Over 80 % of the students agreed that dentists should be legally mandated to report abuse cases and a high percentage (94.3 %) of the participants believed they had an ethical duty to report child abuse. Most students indicated that their dental school was the main source of information on this topic. The majority of the respondents expressed a need for further training.

CONCLUSIONS

Dental students were not sufficiently prepared to know what to look for when they suspect child abuse and what to actually do when they encounter this problem in a professional setting. To provide better care for these young domestic violence victims, dental schools' curriculum modifications should focus on providing students with concrete educational experiences regarding child abuse cases.

Multimodal 3-D reconstruction of human anatomical structures using SurLens Visualization System

In the medical diagnosis and treatment planning, radiologists and surgeons rely heavily on the slices produced by medical imaging devices. Unfortunately, these image scanners could only present the 3-D human anatomical structure in 2-D. Traditionally, this requires medical professional concerned to study and analyze the 2-D images based on their expert experience. This is tedious, time consuming and prone to error; expecially when certain features are occluding the desired region of interest. Reconstruction procedures was earlier proposed to handle such situation. However, 3-D reconstruction system requires high performance computation and longer processing time. Integrating efficient reconstruction system into clinical procedures involves high resulting cost. Previously, brain's blood vessels reconstruction with MRA was achieved using SurLens Visualization System. However, adapting such system to other image modalities, applicable to the entire human anatomical structures, would be a meaningful contribution towards achieving a resourceful system for medical diagnosis and disease therapy. This paper attempts to adapt SurLens to possible visualisation of abnormalities in human anatomical structures using CT and MR images. The study was evaluated with brain MR images from the department of Surgery, University of North Carolina, United States and CT abdominal pelvic, from the Swedish National Infrastructure for Computing. The MR images contain around 109 datasets each of T1-FLASH, T2-Weighted, DTI and T1-MPRAGE. Significantly, visualization of human anatomical structure was achieved without prior segmentation. SurLens was adapted to visualize and display abnormalities, such as an indication of walderstrom's macroglobulinemia, stroke and penetrating brain injury in the human brain using Magentic Resonance (MR) images. Moreover, possible abnormalities in abdominal pelvic was also visualized using Computed Tomography (CT) slices. The study shows SurLens' functionality as a 3-D Multimodal Visualization System.

Analysis of Surfactants by Thin-Layer Chromatography: A Review

Thin-layer chromatographic analysis of surfactants is presented in this review. Various chromatographic systems useful for the identification, separation and quantification of surfactants are reported. New approaches in thin-layer chromatography enable analysts to separate and determine surfactants in complex mixtures (in various environmental samples). Thin-layer chromatographic methods are mainly used for the separation of surfactants either in the separation of different classes or separation of different groups within the same class.

Polyhydroxyalkanoate biosynthesis and simplified polymer recovery by a novel moderately halophilic bacterium isolated from hypersaline microbial mats

AIMS

Halophilic micro-organisms have received much interest because of their potential biotechnological applications, among which is the capability of some strains to synthesize polyhydroxyalkanoates (PHA). Halomonas sp. SK5, which was isolated from hypersaline microbial mats, accumulated intracellular granules of poly(3-hydroxybutyrate) [P(3HB)] in modified accumulation medium supplemented with 10% (w/v) salinity and 3% (w/v) glucose.

METHODS AND RESULTS

A cell density of approximately 3.0 g l(-1) was attained in this culture which yielded 48 wt% P(3HB). The bacterial strain was also capable of synthesizing poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] when cofed with relevant precursors. Feeding with sodium valerate (0.7 mol l(-1) carbon) at various time intervals within 36 h resulted in 3HV molar fractions ranging from 6 up to 54 mol%. Oil palm trunk sap (OPTS) and seawater as the carbon source and culture medium respectively facilitated a significant accumulation of P(3HB). Simplified downstream processing based on osmotic lysis in the presence of alkali/detergent for both dry and wet biomass resulted in approximately 90-100% recovery of polymers with purity as high as 90%. Weight-average molecular weight (M(w) ) of the polymers recovered was in the range of 1-2 × 10(6) .

CONCLUSIONS

Halomonas sp. SK5 was able to synthesize P(3HB) homopolymer as well as P(3HB-co-3HV) copolymer from various carbon sources.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first time a comprehensive study of both production and downstream processing is reported for Halomonas spp.

Oral hygiene and dental caries in 5- to 6-year-old children in Ajman, United Arab Emirates

OBJECTIVE

To investigate the association between oral hygiene and dental caries in young children in the Emirate of Ajman, United Arab Emirates.

METHODS

A one-stage cluster sample was used to randomly select children. Clinical examinations were conducted by a single examiner. Parents completed questionnaires seeking information on child and family characteristics, dietary habits and oral hygiene practices.

RESULTS

The total number of children sampled was 1297. Dental examination and questionnaire data were obtained for 1036 (79.9%). Frequency of eating per day and snack consumption level were both significantly associated with plaque score. Children who brushed their teeth more often had lower plaque scores. The observed association between mean plaque score and mean decayed, missing, filled teeth suggests that children with high plaque scores are more likely to experience caries.

CONCLUSIONS

Brushing with fluoride toothpaste was under-utilized in Ajman. Tooth brushing therefore needs better promotion and reinforcement.

Optimisation of glycaemic control during episodes of severe/acute hyperglycaemia in patients with type 2 diabetes mellitus

BACKGROUND

Patients with type 2 diabetes mellitus (T2DM) are frequently admitted to the hospital with severe or acute hyperglycaemia secondary to an acute illness or disease. Uncontrolled glycaemia is a significant problem during severe or acute hyperglycaemia.

OBJECTIVE

This study sought to identify demographic, clinical, and genetic factors that may contribute to increased insulin resistance or worsening of glycaemic control in patients with T2DM.

SETTING

This prospective cohort study included 156 patients with T2DM and severe or acute hyperglycaemia who were treated with insulin at any medical ward of the National University of Malaysia Medical Centre.

METHOD

Insulin resistance was determined using the homeostatic model assessment-insulin resistance index. Glycaemic control during the episode of hyperglycaemia was assessed as the degree to which the patient achieved the target glucose levels. The polymerase chain reaction-restriction fragment length polymorphism method was used to identify polymorphisms in insulin receptor substrate (IRS) genes.

MAIN OUTCOME MEASURE

Identification of possible predictors (demographic, clinical, or genetic) for insulin resistance and glycaemic control during severe/acute hyperglycaemia.

RESULTS

A polymorphism in IRS1, r.2963 G>A (p.Gly972Arg), was a significant predictor of both insulin resistance [odds ratios (OR) 4.48; 95 % confidence interval (CI) 1.2-16.7; P = 0.03) and worsening of glycaemic control (OR 6.04; 95 % CI 0.6-64.6; P = 0.02). The use of loop diuretics (P < 0.05) and antibiotics (P < 0.05) may indirectly predict worsening of insulin resistance or glycaemic control in patients with severe/acute hyperglycaemia.

CONCLUSION

Clinical and genetic factors contribute to worsening of insulin resistance and glycaemic control during severe/acute hyperglycaemia in patients with T2DM. Early identification of factors that may influence insulin resistance and glycaemic control may help to achieve optimal glycaemic control during severe/acute hyperglycaemia.

Investigation of mothers' knowledge of dental trauma management in United Arab Emirates

AIM

To assess, by means of a structured questionnaire, mothers' level of knowledge with regards to the immediate emergency management of dental trauma in the Emirate of Ajman, United Arab Emirates (UAE).

METHODS

A cross-sectional study using anonymous structured questionnaires was employed for mothers chosen at random from child care centres. The questionnaire surveyed mothers' background, knowledge and management of tooth fracture, avulsion, and also investigated mothers' self-assessed knowledge of the availability and priority of emergency services of trauma in UAE.

RESULTS

The sample consisted of 676 mothers (response rate 96.6%) who attended mother and child care centres in Ajman over a period of two months (January-February 2011). More than half of the mothers participated in this study were in their twenties and 69.4% had university qualifications. Around 61.5% of the mothers had previous direct or indirect experience of dental trauma. Mother's knowledge of dental trauma seemed to be inadequate. Chi-square test indicated that there was no significant difference in the number of correct responses in relation to age, level of education, or number of observed trauma cases. Most mothers were unaware of the availability of after working hours emergency services. They were dissatisfied with their level of knowledge of dental trauma and the majority were interested in having further education on the topic.

CONCLUSIONS

The level of knowledge of dental trauma management (especially tooth avulsion) among mothers in Ajman was inadequate and education campaigns are necessary to improve the emergency management of dental injuries. Therefore it is important to educate the public of the availability of after hours dental emergency services to overcome any delay in seeking professional help in cases of dental trauma.

Neuronal correlates of a preference for leading signals in the synchronizing bushcricket Mecopoda elongata (Orthoptera, Tettigoniidae)

Acoustically interacting males of the tropical katydid Mecopoda elongata synchronize their chirps imperfectly, so that one male calls consistently earlier in time than the other. In choice situations, females prefer the leader signal, and it has been suggested that a neuronal mechanism based on directional hearing may be responsible for the asymmetric, stronger representation of the leader signal in receivers. Here, we investigated the potential mechanism in a pair of interneurons (TN1 neuron) of the afferent auditory pathway, known for its contralateral inhibitory input in directional hearing. In this interneuron, conspecific signals are reliably encoded under natural conditions, despite high background noise levels. Unilateral presentations of a conspecific chirp elicited a TN1 response where each suprathreshold syllable in the chirp was reliably copied in a phase-locked fashion. Two identical chirps broadcast with a 180 deg spatial separation resulted in a strong suppression of the response to the follower signal, when the time delay was 20 ms or more. Muting the ear on the leader side fully restored the response to the follower signal compared with unilateral controls. Time-intensity trading experiments, in which the disadvantage of the follower signal was traded against higher sound pressure levels, demonstrated the dominating influence of signal timing on the TN1 response, and this was especially pronounced at higher sound levels of the leader. These results support the hypothesis that the female preference for leader signals in M. elongata is the outcome of a sensory mechanism that originally evolved for directional hearing.

Simulium (Gomphostilbia) sofiani, a new species of black fly (Diptera: Simuliidae) from peninsular Malaysia

Simulium (Gomphostilbia) sofiani sp. nov. is described on the basis of reared adult female, male, pupal and larval specimens collected from Cameron Highlands, Pahang state, Malaysia. This new species is placed in the ceylonicum species-group within the subgenus Gomphostilbia and is easily distinguished from all the related known species by the combination of the following characteristics: an elongate sensory vesicle and yellow hair tuft on the stem vein of the wing in the female, the greater number of large upper-eye facets (15 or 16 vertical columns and 15 or 16 horizontal rows) and almost entirely darkened hind basitarsus in the male, and the gill bearing a long common basal stalk and 8 filaments arranged as [(1+2)+(1+2)] +2 filaments from dorsal to ventral in the pupa.