Remodeling of Fibrous Extracellular Matrices by Contractile Cells: Predictions from Discrete Fiber Network Simulations

Contractile forces exerted on the surrounding extracellular matrix (ECM) lead to the alignment and stretching of constituent fibers within the vicinity of cells. As a consequence, the matrix reorganizes to form thick bundles of aligned fibers that enable force transmission over distances larger than the size of the cells. Contractile force-mediated remodeling of ECM fibers has bearing on a number of physiologic and pathophysiologic phenomena. In this work, we present a computational model to capture cell-mediated remodeling within fibrous matrices using finite element based discrete fiber network simulations. The model is shown to accurately capture collagen alignment, heterogeneous deformations, and long-range force transmission observed experimentally. The zone of mechanical influence surrounding a single contractile cell and the interaction between two cells are predicted from the strain-induced alignment of fibers. Through parametric studies, the effect of cell contractility and cell shape anisotropy on matrix remodeling and force transmission are quantified and summarized in a phase diagram. For highly contractile and elongated cells, we find a sensing distance that is ten times the cell size, in agreement with experimental observations.Comment: Accepted for publication in the Biophysical Journa

Detection of DNA and Poly-L-Lysine using CVD Graphene-channel FET Biosensors

A graphene channel field-effect biosensor is demonstrated for detecting the binding of double-stranded DNA and poly-l-lysine. Sensors consist of CVD graphene transferred using a clean, etchant-free transfer method. The presence of DNA and poly-l-lysine are detected by the conductance change of the graphene transistor. A readily measured shift in the Dirac Voltage (the voltage at which the graphenes resistance peaks) is observed after the graphene channel is exposed to solutions containing DNA or poly-l-lysine. The Dirac voltage shift is attributed to the binding/unbinding of charged molecules on the graphene surface. The polarity of the response changes to positive direction with poly-l-lysine and negative direction with DNA. This response results in detection limits of 8 pM for 48.5 kbp DNA and 11 pM for poly-l-lysine. The biosensors are easy to fabricate, reusable and are promising as sensors of a wide variety of charged biomolecule

Low-power photothermal self-oscillation of bimetallic nanowires

We investigate the nonlinear mechanics of a bimetallic, optically absorbing SiN-Nb nanowire in the presence of incident laser light and a reflecting Si mirror. Situated in a standing wave of optical intensity and subject to photothermal forces, the nanowire undergoes self-induced oscillations at low incident light thresholds of $<1\, \rm{\mu W}$ due to engineered strong temperature-position ($T$-$z$) coupling. Along with inducing self-oscillation, laser light causes large changes to the mechanical resonant frequency $\omega_0$ and equilibrium position $z_0$ that cannot be neglected. We present experimental results and a theoretical model for the motion under laser illumination. In the model, we solve the governing nonlinear differential equations by perturbative means to show that self-oscillation amplitude is set by the competing effects of direct $T$-$z$ coupling and $2\omega_0$ parametric excitation due to $T$-$\omega_0$ coupling. We then study the linearized equations of motion to show that the optimal thermal time constant $\tau$ for photothermal feedback is $\tau \to \infty$ rather than the widely reported $\omega_0 \tau = 1$. Lastly, we demonstrate photothermal quality factor ($Q$) enhancement of driven motion as a means to counteract air damping. Understanding photothermal effects on micromechanical devices, as well as nonlinear aspects of optics-based motion detection, can enable new device applications as oscillators or other electronic elements with smaller device footprints and less stringent ambient vacuum requirements.Comment: New references adde

ASSESSMENT OF PRESCRIBING PATTERN AMONG ORTHOPEDIC IN-PATIENTS USING WHO PRESCRIBING INDICATORS

Objective: Evaluating the prescribing indicators regularly help to monitor the prescriptions to reduce indiscriminate use of drugs. The present study was conducted to explore the prescribing pattern in orthopedic in-patients using the WHO prescribing indicators in a tertiary care teaching hospital, Mangalore.Methods: Data was collected from case records of orthopedic in-patients regarding patient demographics, diagnosis, and details of drugs in a structured pro forma and analyzed for the WHO prescribing indicators using descriptive statistics. Values are expressed as mean ± standard deviation, percentages as applicable.Results: A total of 379 patient prescriptions were included in the study which consisted of 2195 drugs. Of the 379 patients, 221 (58.3%) were male and 158 (41.7%) were female. The mean age group of the patients was 44 years. Acute trauma such as fractures, tendon damage, and disc prolapse (57.8%) were the most common indications for admission. Analgesics were the most commonly prescribed group of drugs comprising 27.28% of the prescriptions followed by multivitamins (20.68%) and proton-pump inhibitors (17.12%). The most commonly prescribed analgesic was nonsteroidal anti-inflammatory drugs (86.81%). Most of the drugs (65.80%) were administered through the oral route and 40.31% of drugs were fixed-dose combinations. The mean number of drugs per prescription was 5.79± 2.59. Antibiotics were prescribed in 60.4% of the prescriptions. 76.3% of prescriptions were with injectables. Use of drugs by generic name was 7.7% and only 44% of drugs were from the national list of essential medicines 2015.Conclusion: The study provides an insight into the prescribing pattern in orthopedic in-patients. It highlights the importance of emphasizing rational drug prescribing and toward improving awareness of the physicians and medical students to the WHO recommended standards on prescribing indicators

Multiple-Dose activated Charcoal for treatment of Yellow Oleander Poisoning: A Single-blind, Randomised, Placebo - Controlled Trial

INTRODUCTION: Yellow oleander poisoning is the most common plant poisoning in South India. It being a cardiac glycoside has significant cardiac toxicity and a mortality rate of about 10%1. In Madras Medical College, Chennai, Poison Centre alone, there were 210 persons admitted with oleander poisoning during the period September 1, 2001 to May 31, 2004 with a mortality rate of 11.43%2. Specialized treatment with antidigoxin fab fragments and cardiac pacing is expensive and not widely available. Multiple dose activated charcoal binds cardiac glycosides in the gut lumen and promotes their elimination. Aim of the study was to assess the efficacy of multiple dose activated charcoal in the treatment of patients with yellow oleander poisoning. During the period June 1, 2004 to May 31, 2005 there were 63 cases of yellow oleander poisoning at the IMCU / Poison Centre of Madras Medical College, Chennai and the study included 47 patients who met the inclusion criteria. OBJECTIVES: Aim of the study was to assess between the two arms of the trial whether: a) Any significant reduction in mortality. b) Any reduction in occurrence of major or life threatening cardiac arrhythmias. c) Any reduction in the doses of other drugs-atropine- needed. d) Any significant reduction in the number of days of stay in the hospital. MATERIALS AND METHODS: Patients admitted during the period, June 1, 2004 to May 31, 2005 to the poison centre of Madras Medical College, Chennai, were included for the trial. Patients aged 12 – 70 years who were admitted within 24 hours of ingestion of yellow oleander seeds were eligible for inclusion. Patients who had taken another drug such as alcohol, organophosphates, paracetamol or sedatives, had other debilitating diseases like diabetes mellitus, hepatic or renal disease, heart failure or malignant disease, had abdominal surgery within the past 1 year were excluded from the trial. Patients with known hypersensitivity to activated charcoal, those with severe infections and pregnant and lactating women also excluded. Patients who received corticosteroids as part of treatment, as suggested by cardiologist, were also excluded from the study, to avoid confounding. Patients were informed about the nature, objectives, importance, expected benefits and possible adverse effects of the treatment. If the patient did not give the consent, permission from a parent, spouse or guardian was sought. Patients were told they were free to withdraw from the trial at any time if they wished to do so, without any prejudice to subsequent management. STATISTICAL ANALYSIS: Statistical analysis was carried out for 47 subjects- 23 persons in the single dose activated charcoal and placebo group and 24 persons in the multiple dose charcoal group-after categorizing each variable. Patient’s age, sex, weight, no of seeds, seeds crushed or not, time taken after ingestion was matched. Other base line parameters like pulse rate, blood pressure, serum potassium level, serum sodium level, B. Urea, & S. Creatinine were analysed. Occurrence of cardiac arrhythmias at presentation and at 24 hours after presentation, dose of atropine required, no of days for normalisation of ECG and duration of stay in hospital were evaluated& compared. Microsoft excel and SPSS (Statistical package for social sciences) were used for analysis and Z tests were done to assess differences between percentages and difference between means. Analysis was by intention to treat. Statistical significance was taken when P<0.05. CONCLUSION: The following are conclusions from the study: 1. Multiple dose activated charcoal is safe and effective in the treatment of oleander seed poisoning and it reduced the atropine requirement significantly. 2. It is effective in reducing death and life threatening cardiac arrhythmias in oleander seed poisoning. But this reduction is not statistically significant. This impression in this study may be due to smaller sample size. 3. There was no reduction in the number of days of stay in the hospital or in the number of days taken for normalisation of ECG

Smart Farming Solution Using Embedded System

Agricultural sector is going to face enormous difficulties since it has to feed 9.6 billion people by 2050, Therefore food production must increase by 70% by 2050. One way to address this issue and increase the quality and quantity of agricultural production is using sensing technology to make farming simple and it is called as smart farming. Smart farming has a potential to deliver a more productive and sustainable production and uses more precise and resource-efficient approach

Diagnostic accuracy of HE4 and risk of ovarian malignancy algorithm in prediction of ovarian cancer in patients with pelvic mass: a regional cancer centre experience

Background: The current study was performed with an objective to evaluate the diagnostic accuracy of HE4 (human epididymis protein) and ROMA in prediction of ovarian cancer in patients with pelvic mass and to compare HE4 and ROMA with CA-125, and RMI (risk of malignancy index) for ovarian cancer prediction in women with pelvic mass.Methods: This was a diagnostic study enrolling 200 patients with pelvic mass who had been scheduled for Primary surgery. Serum HE4 and CA 125 levels were measured. HE4, CA 125 and ROMA, RMI were evaluated for sensitivity, specificity, positive predictive value and negative predictive value. The receiver operating characteristic (ROC) plots were graphed and area under the curve (AUC) values was calculated to investigate the accuracy of each marker for predicting ovarian malignancy.Results: Overall, ROMA showed the highest accuracy as it correctly classified 139/200 (69.5%) patients compared with 133/200 (66.5%) in HE4 and 109/200 (54.5%) in CA 125 and RMI. There were more patients with benign tumors being correctly identified by HE4 (89/119, 74.7%) and ROMA (74/119, 62.1%), than CA 125 which identified 39/119 (32.7%) patients. In our study in premenopausal women ROMA and HE4 have comparable sensitivity (80%and 75%) but higher specificity (64% and 65%) and NPV (86% and 83%) as compared to CA125 which has sensitivity of (83%) but very low specificity (46%) in differentiating benign from malignant masses. In postmenopausal women, HE4 had highest specificity (88%) and, CA125 has highest sensitivity (86%) in detecting ovarian malignancy.Conclusions: HE4 and ROMA showed a high specificity, but were less sensitivity than CA-125 and RMI in premenopausal women. However, ROMA is of comparable sensitivity and HE4 has highest specificity as compared to CA125 in postmenopausal women

Amine impregnated porous silica gel sorbents synthesized from water-glass precursors for CO2 capturing

In this work, porous silica gel-solid beads have been made from economically affordable water-glass precursors via sol-gel nano casting technique. A stable nanometric silica sol was prepared first from water glass and studied for surface potential and sol to gel transition. A free-flow, injectable gel was obtained upon aging the sol which was then assembled into spherical silica beads in a chemical bath. A surface area of 304.7m2g-1 was obtained for water glass derived silica gel beads. These gel beads were impregnated with 3-aminopropyltrimethoxysilane (APTMS) and polyethylenimine (PEI) active functional groups at different percentages for turning the gel beads as sorbents for CO2 gas adsorption. The effect of amine loading on the thermal stability, morphology as well as porosity was studied and was correlated with CO2 adsorption values. Depending upon the amount of amine loaded in the gel support CO2 uptake was found varied. These amine modified silica gel porous adsorbents showed CO2 adsorption capacity at temperatures as low as 100°C; samples modified with 15wt% PEI had CO2 adsorption capacity of 1.16mmolg-1 at 50°C. © 2015 Elsevier B.V

Is the Scyphozoan jellyfish Lychnorhiza malayensis symbiotically associated with the crucifix crab Charybdis feriatus?

Scyphozoan jellyfish (Medusae), the gelatinous invertebrate group, plays a vital role in the global oceanic and coastal ecosystems. By virtue of their floating nature, and horizontal and vertical spread in the water column, they are known to have varied associations with other invertebrates and teleosts, which make them an integral part of the marine ecosystem