Reduction of detection volume in total internal reflection fluorescence microscopy using graphene

We show that it is possible to decrease the thickness of the detection volume of total internal reflection fluorescence microscopy (TIRFM) by ~35% using a graphene layer in the interface between glass and water layers of a typical TIRFM structure without sacrificing the fluorescence intensity. The highly mobile surface bound electrons of a graphene mono-layer quenches the fluorophores that are less than ~40 nm away from it. The decreased detection volume using the proposed structure will increase the resolution of' a typical TIRFM technique. We find that the results are qualitatively similar for different incidence angles and polarizations of' the excitation field. So, the proposed structure will also find applications in variants of TIRFM techniques, e.g., where incidence angles and polarizations are varied

Surface plasmon coupled emission enhancement with nanoparticles in the metal layer

We show that it is possible to enhance surface plasmon coupled emission (SPCE) intensity by ∼55% using two dimensional periodic nanoparticle arrays in the glass-metal layer interface of an SPCE structure. The nanoparticles act as coupled nanoantennas. With optimized dimensions and periodicity, the nanoparticle arrays resonate and re-emit intensified SPCE. In this work, two types of nanoparticles such as cuboids and hemispheres are used in the arrays. The optimized dimensions and periodicity of the nanoparticle arrays that lead to enhanced intensity are calculated using the particle swarm algorithm. The increased SPCE intensity will be helpful for using SPCE as a biomolecule detection scheme

Effect of Crystallization Conditions on the Metastable Zone Width and Nucleation Kinetics of p ‐Aminobenzoic Acid in Ethanol

A detailed knowledge of the metastable zone width (MSZW) and nucleation kinetics is vital for the design of batch cooling crystallization processes. Factors such as cooling rate and impeller speed affect the MSZW and nucleation kinetics. Crystallization and dissolution temperatures were measured as a function of cooling rate and impeller speed during the batch cooling crystallization of p ‐aminobenzoic acid (pABA) from ethanol in a 0.5‐L stirred‐tank crystallizer. The polythermal experimental data were analyzed using the Nyvlt and first principles‐based Kashchiev‐Borissova‐Hammond‐Roberts (KBHR) methods. In all experimental cases, the latter model revealed that the nucleation process of pABA in ethanol was dominated by an instantaneous nucleation mechanism. The Nyvlt and KBHR analyses delivered a range of parameter values associated with a power‐law model describing the nucleation rate as well as the concentration of nuclei

MODELLING THE ELECTRON WITH COSSERAT ELASTICITY

Interactions between a finite number of bodies and the surrounding fluid, in a channel for instance, are investigated theoretically. In the planar model here the bodies or modelled grains are thin solid bodies free to move in a nearly parallel formation within a quasi-inviscid fluid. The investigation involves numerical and analytical studies and comparisons. The three main features that appear are a linear instability about a state of uniform motion, a clashing of the bodies (or of a body with a side wall) within a finite scaled time when nonlinear interaction takes effect, and a continuum-limit description of the body–fluid interaction holding for the case of many bodies

Reminder systems for self uterine massage in the prevention of postpartum blood loss

Background: Uterine massage may significantly reduce post partum blood loss and could be patient-driven.Objective: To assess the effectiveness of an alarm reminder system for self uterine massage in the prevention of post partum blood loss.Design: A random controlled trial.Setting: Meru District Hospital, Kenya.Subjects: One hundred and twenty seven (127) women were randomly assigned to a 15 minute alarm reminder system (71) and non-alarm (56) control arm during the fourth stage of labour.Results: Uterine massage compliance was better in the alarm group compared to the non-alarm group ( Average massage of seven and two in two hours respectively P-value <0.0001), however the difference in blood loss was not significant 45.6 ml (95% CI 43-46) vs 47.1 ml (95% CI 43-52)ml p-value 0.892.Conclusion: Uterine massage compliance is remarkably increased by the use of an alarm reminder

Molecular basis of arsenite (As+3)-induced acute cytotoxicity in human cervical epithelial carcinoma cells

Background: Rapid industrialization is discharging toxic heavy metals into the environment, disturbing human health in many ways and causing various neurologic, cardiovascular, and dermatologic abnormalities and certain types of cancer. The presence of arsenic in drinking water from different urban and rural areas of the major cities of Pakistan, for example, Lahore, Faisalabad, and Kasur, was found to be beyond the permissible limit of 10 parts per billion set by the World Health Organization. Therefore the present study was initiated to examine the effects of arsenite (As+3) on DNA biosynthesis and cell death.Methods: After performing cytotoxic assays on a human epithelial carcinoma cell line, expression analysis was done by quantitative polymerase chain reaction, western blotting, and flow cytometry.Results: We show that As+3 ions have a dose- and time-dependent cytotoxic effect through the activation of the caspase-dependent apoptotic pathway. In contrast to previous research, the present study was designed to explore the early cytotoxic effects produced in human cells during exposure to heavy dosage of As+3 (7.5 μg/ml). Even treatment for 1 h significantly increased the mRNA levels of p21 and p27 and caspases 3, 7, and 9. It was interesting that there was no change in the expression levels of p53, which plays an important role in G2/M phase cell cycle arrest.Conclusion: Our results indicate that sudden exposure of cells to arsenite (As+3) resulted in cytotoxicity and mitochondrial-mediated apoptosis resulting from up-regulation of caspases.Keywords: apoptosis; epithelial carcinoma; cytotoxicity; arsenite; caspases; Pakistan Responsible Editor: Amin Bredan, VIB Inflammation Research Center & Ghent University, Belgium

Synthesis and antibacterial study of some s-substituted aliphatic analogues of 2-mercapto-5-(1-(4-toluenesulfonyl) piperidin-4-yl)-1,3,4-oxadiazole

Purpose: To synthesize a series of analogues of 1,3,4-oxadiazole and to evaluate their antibacterial activity.Methods: Ethyl piperidin-4-carboxylate (1) was mixed with 4-toluenesulfonyl chloride (2) in benignant conditions to yield ethyl 1-(4-toluenesulfonyl)piperidin-4-carboxylate (3) and then 1-(4- toluenesulfonyl)piperidin-4-carbohydrazide (4). Intermolecular cyclization of 4 into 2-mercapto-5-(1-(4- toluenesulfonyl) piperidin-4-yl)-1,3,4-oxadiazole (5) was obtained on reflux with CS2 in the presence of KOH. Molecule 5 was stirred with alkyl halides, 6a-i, in DMF in the presence of LiH to synthesize the final compounds, 7a-i. The structures of these molecules were elucidated by Fourier transform infra-red (FTIR) spectroscopy, proton nuclear magnetic resonance (1H-NMR) and electron impact mass spectrometry (EI-MS). Antibacterial activity was evaluated against five bacterial strains, namely, Salmonella typhi, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis, with ciprofloxacin used as standard antibacterial agent.Results: Out of nine synthesized derivatives, compound 7a was the most active against three bacterial strains, S. typhi, E. coli and P. aeruginosa, with minimum inhibitory concentration (MIC) of 9.11 ± 0.40, 9.89 ± 0.45 and 9.14 ± 0.72 μM, respectively, compared with 7.45 ± 0.58, 7.16 ± 0.58 and 7.14 ± 0.18 μM, respectively, for the reference standard (ciprofloxacin). Similarly, compounds 7a - 7c showed relatively good antibacterial activity against B. subtilis strain while compound 7e - 7g revealed good results against S. typhi bacterial strain.Conclusion: The results indicate that S-substituted derivatives of the parent compound are more effective antibacterial agents than the parent compound, even with minor differences in substituents.Keywords: 1,3,4-Oxadiazole, Antibacterial activity, Ethyl piperidin-4-carboxylate, Sulfonamid

Graphitic Carbon Nitride Nanosheet-Carbon Nanotube Three-Dimensional Porous Composites as High-Performance Oxygen Evolution Electrocatalysts

Australian Research Council (ARC). Grant Numbers: DP140104062, DP13010445

IL-22 mediates goblet cell hyperplasia and worm expulsion in intestinal helminth infection.

Type 2 immune responses are essential in protection against intestinal helminth infections. In this study we show that IL-22, a cytokine important in defence against bacterial infections in the intestinal tract, is also a critical mediator of anti-helminth immunity. After infection with Nippostrongylus brasiliensis, a rodent hookworm, IL-22-deficient mice showed impaired worm expulsion despite normal levels of type 2 cytokine production. The impaired worm expulsion correlated with reduced goblet cell hyperplasia and reduced expression of goblet cell markers. We further confirmed our findings in a second nematode model, the murine whipworm Trichuris muris. T.muris infected IL-22-deficient mice had a similar phenotype to that seen in N.brasiliensis infection, with impaired worm expulsion and reduced goblet cell hyperplasia. Ex vivo and in vitro analysis demonstrated that IL-22 is able to directly induce the expression of several goblet cell markers, including mucins. Taken together, our findings reveal that IL-22 plays an important role in goblet cell activation, and thus, a key role in anti-helminth immunity

Sample entropy analysis for the estimating depth of anaesthesia through human EEG signal at different levels of unconsciousness during surgeries

Estimating the depth of anaesthesia (DoA) in operations has always been a challenging issue due to the underlying complexity of the brain mechanisms. Electroencephalogram (EEG) signals are undoubtedly the most widely used signals for measuring DoA. In this paper, a novel EEG-based index is proposed to evaluate DoA for 24 patients receiving general anaesthesia with different levels of unconsciousness. Sample Entropy (SampEn) algorithm was utilised in order to acquire the chaotic features of the signals. After calculating the SampEn from the EEG signals, Random Forest was utilised for developing learning regression models with Bispectral index (BIS) as the target. Correlation coefficient, mean absolute error, and area under the curve (AUC) were used to verify the perioperative performance of the p roposed method. Validation comparisons with typical nonstationary signal analysis methods (i.e., recurrence analysis and permutation entropy) and regression methods (i.e., neural network and support vector machine) were conducted. To further verify the accuracy and validity of the proposed methodology, the data is divided into four unconsciousness-level groups on the basis of BIS levels. Subsequently, analysis of variance (ANOVA) was applied to the corresponding index (i.e., regression output). Results indicate that the correlation coefficient improved to 0.72 ± 0.09 after filtering and to 0.90 ± 0.05 after regression from the initial values of 0.51 ± 0.17. Similarly, the final mean absolute error dramatically declined to 5.22 ± 2.12. In addition, the ultimate AUC increased to 0.98 ± 0.02, and the ANOVA analysis indicates that each of the four groups of different anaesthetic levels demonstrated significant difference from the nearest levels. Furthermore, the Random Forest output was extensively linear in relation to BIS, thus with better DoA prediction accuracy. In conclusion, the proposed method provides a concrete basis for monitoring patients' anaesthetic level during surgeries.variou