Effects of low-powered RF sweep between 0.01-20 GHz on female Aedes Aegypti mosquitoes: A collective behaviour analysis.

There are many products claiming to be an electronic solution towards repelling mosquitoes. Several reviews were published in debunking these claims. However, there is a lack of a systematic study on effects of electromagnetic (EM) or more specifically, radio frequency (RF) waves against mosquitoes due to the conclusions made in those years. Therefore, we attempt to establish a fundamental study on female Aedes Aegypti (Linnaeus) mosquitoes by quantifying the collective behavior of the mosquitoes against a continuous stream of low-powered RF signals via a broadband horn antenna using image processing methods. By examining the average lateral and vertical positions of the mosquitoes versus frequency and time, the data shows negligible consistency in the reactions of the mosquitoes toward the different frequencies ranging from 10 to 20,000.00 MHz, with a step of 10 MHz. This was done by examining 33 hours of spatiotemporal data, which was divided into three sessions. All three sessions showed totally different convolutions in the positions in arbitrary units based on the raster scan of the image processing output. Several frequencies apparently showed up to 0.2-70% shift in both lateral and vertical components along the spectrum, without repeatability for all three sessions. This study contributes to the following: A pilot study for establishing the collective effects of RF against mosquitoes, open-source use, and finally a low-cost and easily adaptable platform for the study of EM effects against any insects.

Distribution and abundance of black flies (Diptera: Simuliidae) in recreation parks in Selangor State, Peninsular Malaysia.

A preliminary survey of larvae and pupae of black flies (Diptera: Simuliidae) was conducted in three recreation parks [Templer Recreation Park (TRP), Congkak River Forest Reserve (CRFR) and Ampang Forest Reserve (AFR)] located in Selangor State, which is located 18 to 35 km from Kuala Lumpur city center, Malaysia. This study was initiated to determine the distribution and abundance of filarial vectors, Simulium spp. A total of 12 species of black flies belonging to three subgenera (Gomphostilbia, Simulium and Nevermannia) were collected. Simulium (Simulium) nobile was incriminated as the most dominant species in all recreation parks. This study is a first report on the distribution and abundance of black flies obtained from recreation parks in Malaysia.

Distribution and abundance of black flies (Diptera: Simuliidae) in recreation parks in Selangor State, Peninsular Malaysia

A preliminary survey of larvae and pupae of black flies (Diptera: Simuliidae) was conducted in three recreation parks [Templer Recreation Park (TRP), Congkak River Forest Reserve (CRFR) and Ampang Forest Reserve (AFR)] located in Selangor State, which is located 18 to 35 km from Kuala Lumpur city center, Malaysia. This study was initiated to determine the distribution and abundance of filarial vectors, Simulium spp. A total of 12 species of black flies belonging to three subgenera (Gomphostilbia, Simulium and Nevermannia) were collected. Simulium (Simulium) nobile was incriminated as the most dominant species in all recreation parks. This study is a first report on the distribution and abundance of black flies obtained from recreation parks in Malaysia.

First molecular genotyping of A302S mutation in the gamma aminobutyric acid (GABA) receptor in Aedes albopictus from Malaysia.

Given the lack of molecular evidence in altered target-site insecticide resistance mechanism in Aedes albopictus (Skuse) worldwide, the present study aims to detect the presence of A302S mutation in the gene encoding the gamma aminobutyric acid receptor resistant to dieldrin (Rdl) in Ae. albopictus for the first time from its native range of South East Asia, namely Malaysia. World Health Organization (WHO) adult susceptibility bioassay indicated a relatively low level of dieldrin resistance (two-fold) in Ae. albopictus from Petaling Jaya, Selangor. However, PCR-RFLP and direct sequencing methods revealed the presence of the A302S mutation with the predomination of heterozygous genotype (40 out of 82 individuals), followed by the resistant genotype with 11 individuals. This study represents the first field evolved instance of A302S mutation in Malaysian insect species.

First molecular genotyping of A302S mutation in the gamma aminobutyric acid (GABA) receptor in Aedes albopictus from Malaysia

Given the lack of molecular evidence in altered target-site insecticide resistance mechanism in Aedes albopictus (Skuse) worldwide, the present study aims to detect the presence of A302S mutation in the gene encoding the gamma aminobutyric acid receptor resistant to dieldrin (Rdl) in Ae. albopictus for the first time from its native range of South East Asia, namely Malaysia. World Health Organization (WHO) adult susceptibility bioassay indicated a relatively low level of dieldrin resistance (two-fold) in Ae. albopictus from Petaling Jaya, Selangor. However, PCR-RFLP and direct sequencing methods revealed the presence of the A302S mutation with the predomination of heterozygous genotype (40 out of 82 individuals), followed by the resistant genotype with 11 individuals. This study represents the first fieldevolved instance of A302S mutation in Malaysian insect species.

Multiple resistance of Culex vishnui Theobald against four major classes of insecticides in an agricultural area in Sekinchan, Selangor, Malaysia.

The resistance status of riceland Culex vishnui against four major groups of insecticides (i.e., organochlorines, carbamates, organophosphates and pyrethroids) was investigated. Biochemical assays (ESTα, ESTß, MFO and GST) were also conducted to detect the resistance levels. Throughout a 12-month study period, multiple insecticide resistance was observed in both larvae and adult Cx vishnui. Culex vishnui larvae exhibited low resistance against malathion, temephos and permethrin with resistance ratio (RR) values < 5. In adult bioassay, Cx. vishnui were highly resistant against all tested adulticides with 24h post-treatment mortality < 70%. Correlations between permethrin and malathion resistance, as well as between deltamethrin and cyfluthrin resistance were found in Cx. vishnui. The results indicated that mixed function oxidases activity of Cx. vishnui was the highest compared to ESTα, ESTß and GST. Spearman rank-order analysis showed that ESTα, ESTß and GST were involved in multiple resistances in Cx. vishnui. The findings of this study established a baseline of insecticide susceptibility and revealed the effects of agricultural insecticide pressure on the vectors of Japanese encephalitis in Malaysia.

Current susceptibility status of Malaysian Culex quinquefasciatus (Diptera: Culicidae) against DDT, propoxur, malathion, and permethrin.

A nationwide investigation was carried out to determine the current susceptibility status of Culex quinquefasciatus Say populations against four active ingredients representing four major insecticide classes: DDT, propoxur, malathion, and permethrin. Across 14 study sites, both larval and adult bioassays exhibited dissimilar trends in susceptibility. A correlation between propoxur and malathion resistance and between propoxur and permethrin resistance in larval bioassays was found. The results obtained from this study provide baseline information for vector control programs conducted by local authorities. The susceptibility status of this mosquito should be monitored from time to time to ensure the effectiveness of current vector control operations in Malaysia.

Surgical complications in parenteral Subutex abusers.

INTRODUCTION: There were anecdotal reports of an increase in the admissions of parenteral Subutex abusers to our hospital over the past five months. This case study aimed to analyse the surgical complications related to parenteral Subutex abuse and describe the demographics of this group of patients. METHODS: We reviewed all admissions to our hospital between July and November 2005. Only parenteral Subutex abusers were included in this case study. RESULTS: A total of 53 parenteral Subutex abusers were admitted during this period. 31 had surgical complications, while 22 presented with medical ones. Of the surgical patients, 12 had cellulitis and thrombophlebitis, six developed abscesses of the limbs, ten were patients with ischaemia and gangrene of the digits and limbs, one had septic arthritis, one had necrotising fasciitis, and one had a pseudoaneurysm of the femoral artery. There were no reported mortalities. Only nine patients needed surgical interventions. Most of the patients are young with a mean age of 34.2 years. There was a male predominance of 92.4 percent (49 out of 53). Malays are more frequently affected (72 percent, n=38), followed by Indians (15 percent, n=8), and Chinese (13 percent, n=7). CONCLUSION: Parenteral Subutex abuse is a rising concern in Singapore. Many patients present to the surgical and orthopaedic departments for limb and vascular complications. Surgery has a limited role in their management, and most are treated conservatively and expectantly. The solution to this emerging trend requires inter-hospital and ministerial collaboration.

Characterization of breast lesion morphology with delayed 3DSSMT: an adjunct to dynamic breast MRI.

The purpose of the study was to determine the sensitivity and specificity of various morphologic criteria in distinguishing malignant from benign breast lesions using a new sequence (3DSSMT) performed immediately after dynamic breast MRI. 3DSSMT combines a water-selective spectral-spatial excitation and an on-resonance magnetization transfer pulse with three-dimensional spoiled gradient-echo imaging. Morphologic features of 87 pathologically confirmed lesions were analyzed. The presence of either skin thickening, or a combination of a spiculated or microlobulated border, with a rim, ductal, linear, or clumped enhancement pattern was 94% specific and 54% sensitive for malignancy. Conversely, the presence of either a perfectly smooth border, a well-defined margin, non-enhancing internal septations, or a macrolobulated border was 97% specific and 35% sensitive for a benign diagnosis. In conclusion, delayed 3DSSMT discriminates a significant number of benign and malignant breast lesions; it has the potential to improve the diagnostic accuracy of dynamic breast MRI.

Bedside chest radiography as part of a postcardiac surgery critical care pathway: a means of decreasing utilization without adverse clinical impact.

OBJECTIVE: To evaluate the use of bedside chest radiography and patient outcome before and after implementation of a cardiac surgery critical care pathway that included guidelines for bedside radiography. DESIGN: A cohort observational study. SETTING: A university hospital in the midwest. PATIENTS: Three groups, of 100 patients each, undergoing cardiac surgery in 1990, 1991, and 1995. INTERVENTION: Introduction of a critical care pathway. MEASUREMENTS: Medical records were retrospectively reviewed in three groups of 100 patients each: before the introduction of the critical care pathway; 2 months after introduction of the pathway in 1991; and 4 yrs after introduction in 1995. Data were analyzed to determine operative risk for each group. Subsequent analyses determined bedside radiography use, total length of hospital stay, and patient outcome (mortality rate, complications requiring intervention, and reoperation) during hospitalization and at outpatient follow-up 15-30 days postdischarge. RESULTS: Total length of hospital stay was shorter for the 1995 group (7.6+/-6.6 days) compared with other groups (prepathway, 11.1+/-10.3 days; 1991 postpathway, 10.2+/-9.6 days; p<.05). The mean numbers of radiographs per patient were as follows: prepathway, 5.1; 1991 postpathway, 5.2; and 1995 postpathway, 3.3. The mean number of radiographs in the 1995 group was significantly lower (p = .02). More patients had the proposed number of two bedside radiographs described in the pathway in the 1995 group compared with the other groups (prepathway, p<.0001; the two-month postpathway group, p = .01). Twenty-three malpositioned catheters/tubes were found in the prepathway and 1991 groups compared with 11 in the 1995 group (p = .02). No statistically significant difference was found in inpatient complications (mediastinal bleeding, pneumothoraces, and pleural effusions), postdischarge complications, reoperations, or mortality rate. CONCLUSION: Introduction of a critical care pathway can decrease the use of bedside radiography without adversely affecting near-term patient outcomes.

Thoracic manifestations of sickle cell disease.

Sickle cell disease is the most common inherited disease in the African American population. Multiorgan pathologic features with a predilection for thoracic organs predominate. Acute cardiopulmonary diseases include acute chest syndrome, pneumonia, and left ventricular failure. Cardiomegaly, pleural effusions, pulmonary consolidation, pulmonary edema on chest radiographs, and ground-glass opacities on computed tomographs are characteristic. Chronic changes include sickle cell lung disease with lung fibrosis, pulmonary arterial hypertension, hyperkinetic circulation related to severe anemia, and thoracic skeletal abnormalities; the latter are H-shaped vertebrae, rib infarction, and extramedullary hematopoesis.