Identification and characterisation of short chain rhamnolipid production in a previously uninvestigated, non-pathogenic marine pseudomonad.

This study aimed to identify and characterise biosurfactant compounds produced by bacteria associated with a marine eukaryotic phytoplankton bloom. One strain, designated MCTG214(3b1), was isolated by enrichment with polycyclic aromatic hydrocarbons and based on 16S rDNA, and gyrB sequencing was found to belong to the genus Pseudomonas, however not related to P. aeruginosa. Cell-free supernatant samples of strain MCTG214(3b1) at stationary phase showed significant reductions in surface tension. HPLC-MS and NMR analysis of these samples indicated the presence of five different rhamnolipid (RL) congeners. Di-rhamnolipids accounted for 87% relative abundance and all congeners possessed fatty acid moieties consisting of 8-12 carbons. PCR screening of strain MCTG214(3b1) DNA revealed homologues to the P. aeruginosa RL synthesis genes rhlA and rhlB; however, no rhlC homologue was identified. Using the Galleria mellonella larvae model, strain MCTG214(3b1) was demonstrated to be far less pathogenic than P. aeruginosa. This study identifies for the first time a significantly high level of synthesis of short chain di-rhamnolipids by a non-pathogenic marine Pseudomonas species. We postulate that RL synthesis in Pseudomonas sp. MCTG214(3b1) is carried out by enzymes expressed from rhlA/B homologues similar to those of P. aeruginosa; however, a lack of rhlC potentially indicates the presence of a second novel rhamnosyltransferase responsible for the di-rhamnolipid congeners identified by HPLC-MS.

Imaging molecular adsorption and desorption dynamics on graphene using terahertz emission spectroscopy.

Being an atomically thin material, graphene is known to be extremely susceptible to its environment, including defects and phonons in the substrate on which it is placed as well as gas molecules that surround it. Thus, any device design using graphene has to take into consideration all surrounding components, and device performance needs to be evaluated in terms of environmental influence. However, no methods have been established to date to readily measure the density and distribution of external perturbations in a quantitative and non-destructive manner. Here, we present a rapid and non-contact method for visualizing the distribution of molecular adsorbates on graphene semi-quantitatively using terahertz time-domain spectroscopy and imaging. We found that the waveform of terahertz bursts emitted from graphene-coated InP sensitively changes with the type of atmospheric gas, laser irradiation time, and ultraviolet light illumination. The terahertz waveform change is explained through band structure modifications in the InP surface depletion layer due to the presence of localized electric dipoles induced by adsorbed oxygen. These results demonstrate that terahertz emission serves as a local probe for monitoring adsorption and desorption processes on graphene films and devices, suggesting a novel two-dimensional sensor for detecting local chemical reactions.

Fluctuation of pain by weather change in musculoskeletal disorders.

In order to find out the fluctuation of pain by weather change, a descriptive cross-sectional study was conducted among 138 individuals having musculoskeletal disorders (MSDs) attending the out patient department (OPD) of Physical Medicine and Rehabilitation, Bangabandhu Sheikh Mujib Medical University (BSMMU) Hospital, Dhaka, during March 2004 to June 2004. Data were collected by face to face interview employing a pre-tested interview schedule containing structured questions. Among 138 respondents, male were predominant (52.2%). Mean age of the respondents was 39.42±10.79 years, while the most common age group was found as '31 to 40 years'. By occupation, majority were housewives (40.58%), followed by businessmen (29.71%), service holder (15.22%), laborer (7.97%), and students (6.52%). The primary sites of pain were back and low back (38.4%), knee (24.6%), leg (8.7%), ankle and heel (8.0%), hand and wrist (6.5%), neck (5.8%), shoulder (5.8%), and elbow (2.2%). Highest number (47.8%) patients reported aching pain, while one fifth (20.3%) of them experienced burning pain. About 36.2 percent respondents mentioned 'prolonged standing' as the main cause of pain aggravation, while almost half (48.6%) of the patients perceived that 'application of heat' was the key relieving factor of their pain. About two third (63%) of the respondents were sensitive to weather change; among them 56.3 percent reported that their pain increased during cold weather. Moreover, more than two third (67.4%) study-patients experienced deterioration of pain due to seasonal variation; of them 59.1 percent reported that their pain was exacerbated in winter season. Of all respondents, less than one third (30.4%) experienced aggravation of pain due to lunar change; of them majority (85.7%) experienced increased pain during dark fortnights. Our study concluded that weather change might have an important role in fluctuation of pain among individuals having musculoskeletal disorders.

Comparison between ultrasound and plain X-ray in evaluating the cause of shoulder pain.

Painful shoulder is a common painful condition among patients. Apart from acute traumatic lesions such as fractures, dislocations, contusions, sprains and ruptured tendons, 85 to 90% of painful shoulders are due to adhesive capsulitis, acute or chronic calcific tendinitis, bursitis, bicipital tendinitis and lesions of the musculotendinous cuff. Arthritis is the cause of less than 5% of painful shoulders. For evaluating conditions of shoulder joint, X-ray has been regarded as only method of choice for long time. Magnetic resonance imaging (MRI) is an alternative procedure but the cost limits its utilization especially in Bangladesh. Ultrasonography is an effective imaging modality in the evaluation of both rotator and non-rotator cuff disorders. Because of low cost and availability, it can be an alternative procedure for the diagnosis of painful shoulder. The present study was conducted to assess ultrasonography as a useful modality in evaluating cases of shoulder pain and to compare the findings with X-ray findings. Thirty two patients with shoulder pain were evaluated by X-ray and Ultrasonography (USG). Clinical diagnosis was done for correlation. To identify the cause of shoulder pain, 100% patients were found normal in plain X-ray. On Ultrasonography (USG) 12.5% patients had displaced long head of biceps, 21.9% had biceps tendinitis, and 3.1% had bursitis. In the assessment of shoulder pathology, USG had a sensitivity of 73.3%, specificity of 88.2%, Positive predictive value (PPV) of 84.6%, Negative predictive value (NPV) of 78.9% and an accuracy of 81.3%. USG is a useful modality for evaluation the shoulder joint in case of painful shoulder even plain X-ray is non conclusive.

Evaluation of surgical management of primary spinal tumours.

Spinal tumours, which are 5-10% of skeletal tumours, cause considerable morbidity and present challenging situations in their management. Surgery is often used in the treatment of spinal tumours. Now a day only few specialized spinal care centers have developed in Bangladesh. The prospective study regarding surgical management of primary spinal tumour might be beneficial for proper planning and patient management. All patients who underwent surgical resection of a primary tumor of the spine between July 2006 and May 2008, at the Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh. Patients were uniformly staged before surgery and baseline demographic and surgical variables were recorded, as well as an evaluation of general health related quality of life were done. Thirty-two patients (16 males and 16 females) were eligible for the study. Average age was 43.25 (range 15 to 85). There were 8(25%) vertebral body and pedicle tumors and 3(9.37%) extradural, 16(50%) intradural-extramedullary and 05(15.67%) intradural intramedullary. Only 5(15.63%) developed complication. In this series out of 32 patients, 15(46.88%) achieved excellent result and 10(31.25%) got good result and 5(15.5%) achieved fair and remaining 2(6.25%) patients achieved poor results after the management. Complete neurological involvement of patient did not show complete recovery. In addition to surgery, radiotherapy and chemotherapy are needed to sterilize the tumour bed. Early detection and surgery of primary spinal tumour give satisfactory results and patient can return to their normal life.

Effects of therapeutic modalities on patients with post stroke shoulder pain.

A randomized clinical trial was conducted to find out the effects of physical modalities transcutaneous electrical nerve stimulation (TENS) and ultrasonic therapy (UST) on the patients with post stroke shoulder pain in the Department of Physical Medicine & Rehabilitation & Department of Neurology, Bangabandhu Sheikh Mujib Medical University (BSMMU) from 1st July 2006 to 31st December 2006. In that period a total of 750 stroke patients attended the stroke clinic of the Department of Neurology, BSMMU, of which 150(20%) patients presented with post stroke shoulder pain. Among the patients with post stroke shoulder pain, 45(6%) patients were included in the study. The aim of the study was to find out the improvement with proper and timely physical therapy and to study the comparative efficacy of TENS or UST therapy on shoulder pain in stroke patients. Results of this study showed that most of the patients were elderly and maximum number of patients (86.66%) was diagnosed as adhesive capsulitis. In each group, pain reduction and increase of muscle strength was same, TENS showed better improvement of muscle strength. There was complete recovery of tenderness by both TENS and UST. Significant improvement was observed after treatment in each group except in active internal rotation in UST group. But in comparison between two groups, Group A (TENS) showed statistically significant better improvement in all planes of pain free range of motion than Group B except active abduction which was better improved in group B (UST) and in case of passive abduction, passive external rotation and passive extension, TENS had better effect than UST. It may be concluded that TENS and UST both are effective but TENS may be safer and superior to ultrasonic therapy (UST) in the treatment of the patients with post stroke shoulder pain.