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Optical nonlinearity in natural dyes extracted from tea leaves, such as black tea (Bt) and green tea (Gt), in different solvents (dimethyl sulfoxide, methanol, ethylene glycol, and deionized water) was measured with a Z-scan technique using a single CW laser at 532 nm, and a novel all-optical limiter based on nonlinear optical responses in natural dyes was presented. Then, the absorption peaks in the 665 and 675 nm regions were detected by UV-vis spectroscopy, and the nonlinear optical parameter n2 for Bt and Gt were determined in different solvents. Finally, power-absorbing and power-spreading configurations were used in investigating all-limiting behavior for Bt and Gt. Results indicated good all-optical limiting behavior, suggesting that tea leaves are potential materials for fabricating all-optical limiter devices used in sensor protection. [ABSTRACT FROM AUTHOR]

Nonlinear optical (NLO) properties of a pure BCP and BCP doped with MEH- PPV solutions, at different doping concentrations and different laser powers were, were studied by the Z-scan technique with a cw laser at 532 nm wavelength. It was found that they depend on the power of used laser. The measurements have shown also that the BCP/MEH-PPV complex exhibits the self-defocusing nonlinearity with large nonlinear refractive index as well as a significative nonlinear absorption. The BCP/MEH-PPV solutions exhibit also an interesting optical power limiting laser with a low threshold. These studies show that the NLO properties of BCP/MEH-PPV solutions may open new possibilities of using them in all-photonic switching elements and in optical power limiting. [ABSTRACT FROM AUTHOR]

Copyright of Al-Mustansiriyah Journal of Science is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Kufa - Physics is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Linear electro-optic (EO) and thermo-optic (TO) effects are jointly considered on the basis of field-induced and temperature-affected perturbations of the operating point along the optical transmission curve of an EO-modulation system. In this framework, methods of EO measurements based on the frequency doubling appearing at the minimum-transmission point are formulated. Moreover, TO coefficients for various optical quantities, such as the refractive indices, n0 and ne, the spontaneous birefringence Δn(0), the EO coefficient r, the half-wave voltage Vπ, the optical phase retardation Γ, and the intensity modulation (IM) depth, m, are introduced and useful relationships between them are extracted. Also, applications of the above in the experimental field, with determinations of EO parameters and TO coefficients, are presented for the case of a congruent LiTaO3 crystal. A comparison of the so-obtained experimental results with those derived from literature when a LiNbO3 crystal is used demonstrates a number of advantages for the LiTaO3-based system. [ABSTRACT FROM AUTHOR]

Linear electro-optic (EO) and thermo-optic (TO) effects are jointly considered on the basis of field-induced and temperature-affected perturbations of the operating point along the optical transmission curve of an EO-modulation system. In this framework, methods of EO measurements based on the frequency doubling appearing at the minimum-transmission point are formulated. Moreover, TO coefficients for various optical quantities, such as the refractive indices, n0 and ne, the spontaneous birefringence Δn(0), the EO coefficient r, the half-wave voltage Vπ, the optical phase retardation Γ, and the intensity modulation (IM) depth, m, are introduced and useful relationships between them are extracted. Also, applications of the above in the experimental field, with determinations of EO parameters and TO coefficients, are presented for the case of a congruent LiTaO3 crystal. A comparison of the so-obtained experimental results with those derived from literature when a LiNbO3 crystal is used demonstrates a number of advantages for the LiTaO3-based system. [ABSTRACT FROM AUTHOR]

Hospital-acquired urinary tract infections (HAUTI) are common and most cases are related to catheters (CAUTI). HAUTI and CAUTI surveillance is mandatory in many countries as a measure to reduce the incidence of infections and appropriately direct the allocation of preventable resources. The surveillance criteria issued by the Israeli Ministry of Health (IMOH), differ somewhat from that of the U.S. Centers for Disease Control and Prevention (CDC). Our study aims were to query and quantify the impact of these differences. In a retrospective cohort study conducted at Shamir Medical Center, for calendar year 2017, the surveillance criteria of both IMOH and CDC were applied on 644 patient-unique adults with "positive" urine cultures (per similar definitions). The incidence of HAUTI per IMOH was significantly higher compared to CDC (1.24/1000 vs. 1.02/1000 patient-days, p = 0.02), with no impact on hospitalization's outcomes. The agreement rate between methods was high for CAUTI (92%), but much lower for all HAUTI (83%). The major error rate, i.e., patients diagnosed with HAUTI per IMOH but had no UTI per CDC, was 31%. To conclude, in order for surveillance to reflect the relative situation and direct allocation of preventable resources based on scientific literature, the process should be uniform worldwide.

Optical folding and rotation behavior of red blood cells (RBCs) in polarized laser tweezers are considerably important for understanding the biophysical and biomechanical properties using the fast probing method. Here, a dual-mode polarized single-laser tweezers technique with distinct principal axes exhibiting different polarization states is presented and designed to investigate the deformation, optical folding, and rotation of single living cells with one measurement. RBC optical folding and rotation speed are measured in patients with sickle cell disease (SCD), including follow up of patients after hydroxyurea (HU) treatment for at least three months. Folding angle and rotation speed are significantly lower in patients with SCD and do not significantly differ in patients treated by HU compared with the healthy control group. The RBC folding angle and rotation speed in patients treated with HU drug increase linearly at lower laser powers and rapidly at higher powers, and increase much slowly in patients not treated with HU. The difference in the folding angle and rotation speed of RBCs could be useful for drug response in SCD or predicting pain crisis in SCD., Competing Interests: Declaration of competing interest ☒ The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021. Published by Elsevier Inc.)

Objective: Administration of antimicrobials to patients with asymptomatic bacteriuria (ASB) is a common error that can lead to worse outcomes. However, controlled analyses quantifying the commonality and impact of this practice are lacking. We analyzed the independent predictors for antimicrobials misuse in ASB and quantified the impact of this practice on clinical outcomes., Design: Retrospective case-control and cohort analyses for calendar year 2017., Setting: Tertiary-care, university-affiliated medical center., Patients: The study included adult (>18 years) patients with positive urine culture. Pregnant women, renal transplant recipients, and patients who underwent urologic procedures were excluded., Methods: ASB was determined according to US Centers for Disease Control and Prevention (CDC) criteria. Multivariable logistic regression models were constructed to analyze predictors and outcomes associated with antimicrobial use for patients with ASB., Results: The study included 1,530 patient-unique positive urine cultures. Among these patients, 610 patients (40%) were determined to have ASB. Of the 696 isolates, 219 (36%) were multidrug-resistant organisms (MDROs). Also, 178 (29%) patients received antimicrobials specifically due to the ASB. Independent predictors for improper administration of antimicrobials were dependent functional status (adjusted odds ratio [aOR], 2.3; 95% CI, 1.4-3.6) and male sex (aOR, 2; 95% CI, 1.25-2.6). Use of antimicrobials was independently associated with re-hospitalizations (aOR, 1.7; 95% CI, 1.1-2.6) and later, acute Clostridioides difficile infections (CDI) in the following 90 days (aOR, 4.5; 95% CI, 2-10.6)., Conclusions: ASB is a common condition, frequently resulting from an MDRO. Male sex and poor functional status were independent predictors for mistreatment, and this practice was independently associated with rehospitalizations and CDI in the following 90 days.

Background: Many septic patients are receiving empirical antipseudomonal (or Gram-negative non-glucose fermenting [GNNGF]) coverage on admission to acute care hospitals, despite the fact that the indications are not scientifically established. Overuse of antipseudomonals might contribute to the burden of resistance., Materials and Methods: Retrospective observational analyses of the characteristics of septic adult patients who received empirical antipseudomonals, along with its impact on outcomes, were executed at Shamir Medical Center, Zerifin, Israel (08-12/2016). Proper empirical antipseudomonal usage was defined by the following: (1) if the patient received the agents as per Infectious Disease Society of America (IDSA) guidelines; (2) if the patient had a positive multidrug-resistant organism (MDRO) test on his or her admission score (https://assafharofe.azurewebsites.net); or (3) if a GNNGF was the eventual causative pathogen. Risk factors and outcomes were queried by logistic and Cox regression., Results: GNNGF was the causative pathogen in only 57 (3.7%) of 1536 patients with acute sepsis. There were 192 (13%) who received empirical antipseudomonals, of whom 161 (84%) were defined as proper. Patients who received empirical antipseudomonals were significantly older (P < 0.001), with higher indices of chronic and acute conditions, and higher rates of past MDRO carriage; 24 patients received empirical antipseudomonals only because of IDSA guidelines (15%), and that was an independent predictor for later acquisition (up to 90 days) of carbapenem-resistant A. baumannii (CRAB; odds ratio [aOR] = 7.1; P = 0.03)., Conclusions: Improper empirical usage of antipseudomonals in acute care hospitals is common. Instituting empirical antipseudomonals solely due to IDSA guidelines was independently associated with later acquisition of CRAB. Empirical antipseudomonal usage should be based on scientifically established prediction tools and not on IDSA guidelines., (Copyright © 2019 International Society for Antimicrobial Chemotherapy. Published by Elsevier Ltd. All rights reserved.)

Background: Trichloroacetic acid (TCA) is a nontoxic chemical that has been used for more than 20 years in skin rejuvenation treatments for various skin conditions. Currently, there is no single accepted protocol for local burn care following TCA peeling., Objective: This pilot study assesses the efficacy and tolerability of a silver-based gel compared with fusidic acid cream as a complementary topical treatment for burns following TCA peeling., Materials and Methods: The authors conducted a comparative study on healthy female patients in the Department of Plastic and Reconstructive Surgery at Assaf Harofe Medical Center (Zerifin, Israel). Patients were treated with TCA 15% for superficial facial skin peeling, followed by applications of both the silver-based gel and fusidic acid cream on opposite sides of their face. Patient evaluation included high-resolution photographic evaluation pre- and post-peeling; physician assessment for the presence of complications such as infection, edema, and allergic reactions; and a self-completed questionnaire in reference to the outcomes and side effects (eg, burning, itching) experienced., Results: Seventeen women were included in the study. None of the patients experienced an infection or allergic reaction. Photographic analysis found no significant differences in the outcomes between topical treatments, with a trend for better results with the silver-based gel. Pain, edema, and burning sensations were not significantly different between the topical treatments. Itching was less prevalent in the silver-based gel group (P = .046)., Conclusions: Comparing between the groups treated with silver-based gel and fusidic acid cream, the authors found no inferiority in the outcomes or the prevalence of any complaints, and a superior effect on the prevention of wound itch using a silver-based gel.