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Identification and minimization of error sources an important issues in experimental investigations. Mainly in micro-scale problems, precise settings should be applied to high-tech test beds to reduce disturbance and induced motion. An experimental study is conducted to assess the role of induced forces and velocity fields in a particulate system used for particle identification and separation. Two main effects caused by disturbances are sampling errors and induced motion in the channel, either on fluid or dispersed phases. Different disturbance scenarios are implemented on the test bed and then the system response is reported. In order to assess induced motion as a result of applied forces, microscopic imaging of particle movement in the channel and image processing of the results, are performed. Results of particle sampling indicate that optimized pneumatic settings should be implemented to secure a safe level of sampling error. Results for induced flow show that the velocity field can affect the operation of the manipulation mechanism. Methods for capturing the induced force and velocity fields can be implemented in the arelevant applications, such as micro-particle systems and cellular studies. [ABSTRACT FROM AUTHOR]

Quorum sensing enables cell-cell communication in bacteria and regulates biofilm formation. Biofilm production promotes pathogenicity of Escherichia coli and causes infections. However, antibiotic resistance limits conventional treatment efficacy against biofilm infections. Quorum quenching offers an alternative by disrupting quorum sensing signals. Allicin, extracted from garlic, possesses antimicrobial and anti-quorum sensing properties. This study employed molecular docking and dynamics simulations to investigate allicin's interaction with the E. coli quorum sensing system, specifically targeting the cytoplasmic SidA receptor protein. SidA binds to N-acyl-homoserine lactone ligands and regulates quorum sensing in E. coli . The crystal structure of SidA was obtained from the PDB. Molecular docking revealed that allicin competitively binds to the ligand-binding pocket of SidA. Simulations analyzed the effects of allicin binding on SidA stability and affinity for N-acyl-homoserine lactones over 200 ns. Parameters like RMSD, RMSF, and hydrogen bonding indicated SidA was more stable when bound to allicin compared to unbound. Binding free energies suggested allicin reduced SidA's affinity for native ligands. Therefore, allicin binding to SidA alters its conformation and inhibits interaction with N-acyl-homoserine lactones, disrupting quorum sensing signaling and biofilm production in E. coli .Communicated by Ramaswamy H. Sarma.

Optical separation, which is a contactless and accurate technique, has been mostly used to manipulate single particles. This work mainly aims to present an effective technique for optical propulsion and separation of a group of microscopic particles that are suspended in liquids. An experimental study is conducted to assess the effect of radiation pressure of a high-power laser on a dilute dispersion of microparticles in water using microscopic image analysis. Results of separation experiments indicate that the manipulation mechanism is capable of sorting the microscopic particles in two size classes. Compared to common optical separators, this configuration has a benefit of separating many particles simultaneously.

Background: Tuberculosis (TB) is one of the main causes of morbidity and mortality in different societies. Understanding factors leading to death following diagnosis of TB is important to predict prognosis in TB patients. The aim of this study was to identify common risk factors associated with death in patients with an in-hospital diagnosis of TB, in a city in Iran with the highest prevalence and incidence of TB in the country., Materials and Methods: A retrospective study was conducted at a university-affiliated hospital, Zahedan, in the south-east of Iran, which is a referral center for TB. To identify factors leading to death, medical records of 715 patients ≥15 years old with pulmonary TB from February 2002 to February 2011 have been evaluated. Registered factors included smoking, human immune deficiency virus (HIV) infection, using drugs, lung cancer, drug hepatitis following anti-TB medications, diabetes mellitus, previous TB treatment, anemia; and results of sputum smears. Univariate comparison and multiple logistic regression were performed to identify factors associated with mortality in TB patients., Results: Among 715 registered TB patients, 375 (52.5%) patients were male; among those, 334 (53%) were in the alive group and 41 (54%) in the death group. Seventy-five (10.5%) of the total number of TB patients died during TB treatment. The multivariate model showed that anemia (AOR: 19.8, 95% CI: 5.6-35.5), positive sputum smear (AOR: 13.4, 95% CI: 6.8-33.6), smoking (AOR: 12.9, 95% CI: 3.9-27.3), drug hepatitis (AOR: 12.3, 95% CI: 6.7-24.7), diabetes mellitus (AOR: 9.7, 95% CI: 2.9-32.0), drug use (AOR: 7.8, 95% CI: 2.4-25.5), and history of previous TB (AOR: 6.8, 95% CI: 2.2-21.3) were major risk factors for death in TB patients., Conclusion: Monitoring co-morbid conditions like diabetes mellitus and anemia are important to reduce death rate in TB patients. Preventive measures for smoking and drug addiction also play an important role to decrease mortality. Follow-up of patients with previous TB treatment is recommended.