Autonomous transport and splitting of a droplet on an open surface

Pumpless transport of droplets on open surfaces has gained significant attention because of its applications starting from vapor condensation to Lab-on-a-Chip systems. Mixing two droplets on open surfaces can be carried out quickly by using wettability patterning. However, it is quite challenging to split a droplet in the absence of external stimuli because of the interfacial energy of the droplet. Here, we demonstrate a standalone power-free technique for transport and splitting of droplets on open surfaces using continuous wettability gradients. A droplet moves continuously from a low to a high wettability region on the wettability-gradient surface. A Y-shaped wettability-gradient track – laid on a superhydrophobic background – is used to investigate the dynamics of the splitting process. A three-dimensional phase-field Cahn-Hilliard model for interfaces and the Navier-Stokes equations for transport are employed and solved numerically using the finite element method. Numerical results are used to decipher the motion and splitting of droplet at the Y junction using the principle of energy conservation. It is observed that droplet splitting depends on the configuration of the Y junction; droplets split faster for the superhydrophobic wedge angle of 90∘ and the splitting ratio (ratio of the sizes of daughter droplets) depends on the widths of the Y branches. A critical branch-width ratio (w2w1=0.79) is identified below which the droplet does not split and moves towards the branch of higher width and settles there. The present study provides the required theoretical underpinnings to achieve autonomous transport and splitting of droplets on open surfaces, which has clear potential for applications in Lab-on-a-Chip devices

Studies on genetic variability and interrelationship in bottle gourd [Lagenaria siceraria (Mol.) Standl]

The genetic parameters were studied to elucidate the genetic variability, correlation and path co-efficient analysis in thirty-nine genotypes of bottle gourd [Lagenaria siceraria (Mol.) Standl] in randomized complete block design with three replications. Observations were recorded for eleven quantitative characters viz., days to first male flower open, days to first female flower open, node number of first female flower, braches plant-1, days to harvest, number of fruits plant-1, fruit weight, fruit length, fruit girth, 100 seed weight and yield ton ha-1. The analysis of variance showed highly significant differences for all the characters studied indicating considerable variability among the genotypes. The highest GCV (35.57%) and PCV (35.62%) were observed for fruit length. The differences between GCV and PCV were high for fruit number plant-1 and days to first male flower open indicating environmental influences. High heritability associates with high estimates of genetic advance in percent of mean were noted for length of fruit, yield, girth of fruit and number of fruits plant-1. It indicated presence of additive gene effect and selection for these traits would be effective. Yield were positively and significantly correlated with fruit weight, 100 seed weight, branch plant-1 and number of fruits plant-1 .Negative associations of yield were noted with days to first male and female flower open, days to harvest and length of fruit. Path analysis revealed that fruits plant-1 (0.93) and weight of fruit (0.467) had very high positive effect on fruit yield ton ha-1 .Int. J. Agril. Res. Innov. & Tech. 8 (1): 14-17, June, 201

Christmas Disease (Hemophilia B) A Case Report

We report a 25 years old man developed Haemarthrosis of left hip joint with a history of recurrent swelling and pain in multiple joints and prolonged bleeding following minor trauma since childhood. Subsequent investigations revealed Christmas disease (Haemophilia B). Hemophilia B is an X-linked bleeding disorder. This case emphasises the importance of considering a diagnosis of haemophilia in a man with unexplained bleeding, even in the absence of a positive family history. DOI: 10.3329/bsmmuj.v2i2.4766 BSMMU J 2009; 2(2): 90-9

Using an Indoor Localization System for Activity Recognition

Recognizing the activity performed by users is importantin many application domains, from e-health to home automation. Thispaper explores the use of a fine-grained indoor localization system, basedon ultra-wideband, for activity recognition. The user is supposed to weara number of active tags. The position of active tags is first determinedwith respect to the space where the user is moving, then some position-independent metrics are estimated and given as input to a previouslytrained system. Experimental results show that accuracy values as highas∼95% can be obtained when using a personalized model

Frequency Shift of Carbon-Nanotube-Based Mass Sensor Using Nonlocal Elasticity Theory

The frequency equation of carbon-nanotube-based cantilever sensor with an attached mass is derived analytically using nonlocal elasticity theory. According to the equation, the relationship between the frequency shift of the sensor and the attached mass can be obtained. When the nonlocal effect is not taken into account, the variation of frequency shift with the attached mass on the sensor is compared with the previous study. According to this study, the result shows that the frequency shift of the sensor increases with increasing the attached mass. When the attached mass is small compared with that of the sensor, the nonlocal effect is obvious and increasing nonlocal parameter decreases the frequency shift of the sensor. In addition, when the location of the attached mass is closer to the free end, the frequency shift is more significant and that makes the sensor reveal more sensitive. When the attached mass is small, a high sensitivity is obtained

A comprehensive situation assessment of injection practices in primary health care hospitals in Bangladesh

<p>Abstract</p> <p>Background</p> <p>Understanding injection practices is crucial for evidence-based development of intervention initiatives. This study explored the extent of injection use and injection safety practices in primary care hospitals in Bangladesh.</p> <p>Methods</p> <p>The study employed both quantitative and qualitative research methods. The methods used were - a retrospective audit of prescriptions (n = 4320), focus group discussions (six with 43 participants), in-depth interviews (n = 38) with a range service providers, and systematic observation of the activities of injection providers (n = 120), waste handlers (n = 48) and hospital facilities (n = 24). Quantitative and qualitative data were assessed with statistical and thematic analysis, respectively, and then combined.</p> <p>Results</p> <p>As many as 78% of our study sample (n = 4230) received an injection. The most commonly prescribed injections (n = 3354) including antibiotics (78.3%), IV fluids (38.6%), analgesics/pain killers (29.4%), vitamins (26.7%), and anti-histamines (18.5%). Further, 43.7% (n = 1145) of the prescribed antibiotics (n = 2626) were given to treat diarrhea and 42.3% (n = 600) of IV fluids (n = 1295) were used to manage general weakness conditions. Nearly one-third (29.8%; n = 36/120) of injection providers reported needle-stick injuries in the last 6 months with highest incidences in Rajshahi division followed by Dhaka division. Disposal of injection needles, syringes and other materials was not done properly in 83.5% (n = 20/24) of the facilities. Health providers' safety concerns were not addressed properly; only 23% (n = 28/120) of the health providers and 4.2% (n = 2/48) of the waste handlers were fully immunized against Hepatitis B virus. Moreover, 73% (n = 87/120) of the injection providers and 90% (n = 43/48) of the waste handlers were not trained in injection safety practices and infection prevention. Qualitative data further confirmed that both providers and patients preferred injections, believing that they provide quick relief. The doctors' perceived injection use as their prescribing norm that enabled them to prove their professional credibility and to remain popular in a competitive health care market. Additionally, persistent pressure from hospital administration to use up injections before their expiry dates also influenced doctors to prescribe injections regardless of actual indications.</p> <p>Conclusions</p> <p>As far as the patients and providers' safety is concerned, this study demonstrated a need for further research exploring the dynamics of injection use and safety in Bangladesh. In a context where a high level of injection use and unsafe practices were reported, immediate prevention initiatives need to be operated through continued intervention efforts and health providers' training in primary care hospitals in Bangladesh.</p

Dynamics of mechanical waves in periodic grapheme nanoribbon assemblies

We simulate the natural frequencies and the acoustic wave propagation characteristics of graphene nanoribbons (GNRs) of the type (8,0) and (0,8) using an equivalent atomistic-continuum FE model previously developed by some of the authors, where the C-C bonds thickness and average equilibrium lengths during the dynamic loading are identified through the minimisation of the system Hamiltonian. A molecular mechanics model based on the UFF potential is used to benchmark the hybrid FE models developed. The acoustic wave dispersion characteristics of the GNRs are simulated using a Floquet-based wave technique used to predict the pass-stop bands of periodic mechanical structures. We show that the thickness and equilibrium lengths do depend on the specific vibration and dispersion mode considered, and that they are in general different from the classical constant values used in open literature (0.34 nm for thickness and 0.142 nm for equilibrium length). We also show the dependence of the wave dispersion characteristics versus the aspect ratio and edge configurations of the nanoribbons, with widening band-gaps that depend on the chirality of the configurations. The thickness, average equilibrium length and edge type have to be taken into account when nanoribbons are used to design nano-oscillators and novel types of mass sensors based on periodic arrangements of nanostructures

New insights into the classification and nomenclature of cortical GABAergic interneurons.

A systematic classification and accepted nomenclature of neuron types is much needed but is currently lacking. This article describes a possible taxonomical solution for classifying GABAergic interneurons of the cerebral cortex based on a novel, web-based interactive system that allows experts to classify neurons with pre-determined criteria. Using Bayesian analysis and clustering algorithms on the resulting data, we investigated the suitability of several anatomical terms and neuron names for cortical GABAergic interneurons. Moreover, we show that supervised classification models could automatically categorize interneurons in agreement with experts' assignments. These results demonstrate a practical and objective approach to the naming, characterization and classification of neurons based on community consensus

Gastric Outlet Obstruction at Bugando Medical Centre in Northwestern Tanzania: A Prospective Review of 184 Cases.

Gastric outlet obstruction poses diagnostic and therapeutic challenges to general surgeons practicing in resource-limited countries. There is a paucity of published data on this subject in our setting. This study was undertaken to highlight the etiological spectrum and treatment outcome of gastric outlet obstruction in our setting and to identify prognostic factors for morbidity and mortality. This was a descriptive prospective study which was conducted at Bugando Medical Centre between March 2009 and February 2013. All patients with a clinical diagnosis of gastric outlet obstruction were, after informed consent for the study, consecutively enrolled into the study. Statistical data analysis was done using SPSS computer software version 17.0. A total of 184 patients were studied. More than two-third of patients were males. Patients with malignant gastric outlet obstruction were older than those of benign type. This difference was statistically significant (p < 0.001). Gastric cancer was the commonest malignant cause of gastric outlet obstruction where as peptic ulcer disease was the commonest benign cause. In children, the commonest cause of gastric outlet obstruction was congenital pyloric stenosis (13.0%). Non-bilious vomiting (100%) and weight loss (93.5%) were the most frequent symptoms. Eighteen (9.8%) patients were HIV positive with the median CD 4+ count of 282 cells/μl. A total of 168 (91.3%) patients underwent surgery. Of these, gastro-jejunostomy (61.9%) was the most common surgical procedure performed. The complication rate was 32.1 % mainly surgical site infections (38.2%). The median hospital stay and mortality rate were 14 days and 18.5% respectively. The presence of postoperative complication was the main predictor of hospital stay (p = 0.002), whereas the age > 60 years, co-existing medical illness, malignant cause, HIV positivity, low CD 4 count (<200 cells/μl), high ASA class and presence of surgical site infection significantly predicted mortality ( p< 0.001). The follow up of patients was generally poor as more than 60% of patients were lost to follow up. Gastric outlet obstruction in our setting is more prevalent in males and the cause is mostly malignant. The majority of patients present late with poor general condition. Early recognition of the diagnosis, aggressive resuscitation and early institution of surgical management is of paramount importance if morbidity and mortality associated with gastric outlet obstruction are to be avoided