Estimation of the conformational characteristics of polyurethane chains

Linear polyurethanes (PUR-D_k) were prepared by reacting 4,4′-methylenediphenyl diisocyanate (MDI) with low-molecular-weight diols HO (CH₂)_k OH (k = 2, 3, 4, and 6) and fractionated by precipitation or extraction with mixtures of N,N-dimethylformamide (DMF) and dibutyl ether (DBE). The fractions were characterized by their weight-average molecular weights M _w (light scattering) and intrinsic viscosities [η] in DMF (good solvent) and mixtures of DMF with DBE (poor solvents). The Kuhn statistical segment length l_K was evaluated from the intrinsic viscosities in poor solvents. Low values of l_K, (12 to 14) × 10⁻⁸ cm, indicate that benzene rings and virtual double bonds (urethane groups) confine neighbour interactions to bonds within the repeating units and assure independent rotations at the bonds adjoining them.     

Impact of Surfactant and Calcium Sulfate Type on Air-Entraining Effectiveness in Concrete

The paper presents the evaluation of the influence of calcium sulfate on the air void microstructure in concrete and its action mechanism depending on the character of the air-entraining agent. Gypsum dehydration has been previously proven to negatively influence the air void structure of air-entrained concrete. Ettringite, nucleating from tricalcium aluminate and calcium sulfate, influences the adsorption and mode of action of anionic-based polycarboxylate ether admixtures. The authors suspected the admixture’s air-entraining mechanism was also affected by these characteristics. Gypsum dehydration was confirmed to influence the air void structure. In the case of the anionic surfactant, the content of air bubbles smaller than 300 µm was lower compared to cement with gypsum and hemihydrate. On the other hand, the content of air voids with a diameter up to 60 µm, which are the most favorable, was higher. The results obtained led to the conclusion that the mechanism of air entrainment was twofold, and in most cases occurred through the lowering of surface tension and/or through the adsorption of surfactant on cement grains. The adsorptive mechanism was proved to be more effective in terms of the total air content and the structure of the air void system. The results and conclusions of the study provide guidelines to determine the proper surfactant type to reduce the risk of improper air entrainment of concrete, and emphasize the importance of gypsum dehydration of cement in the process of air entrainment.     

Knowledge,Practices and Use of Contact Lenses Among University Students in Turkey

AimThis study was conducted to determine the prevalence of contact lens (CL) use among university students, their awareness on CL, and CL users'' practices for the cleaning and care of CLs.MethodsThe data of this cross-sectional study were collected between April 2019 and July 2019. The sample consisted of university students who volunteered to participate in the study. The data obtained from the study were evaluated by Statistical Package for the Social Science (SPSS) 22.0 package program in computer environment.Results929 students participated in the study and the average age of them was 21.99±1.85 years (Min. 18 – Max. 24), and it was determined that 36.6% (n=340) of the participants were male, 10.2% (n=95) of the total were using CL, 91.6% (n=87) of them used CL due to visual impairment. When students'' levels of knowledge about the hygiene and care in CL use were examined 85.4% (n=82) washed their hands before wearing/removing CL, 85.3% (n=81) cleaned the lens container and filled it with new solution when the solution in the container was reduced, 18.5% (n=17) continued wearing CL while sleeping, 6.5% (n=6) washed CL with tap water, and 28.3% (n=26) of them stated that they swam in the sea with CL. It was determined that the prevalence of CL use was higher (p= .045) among smoking students.ConclusionHealth professionals are important in the trainings to be given to increase the students'' knowledge of hygiene and care regarding the use of CL. More studies are needed on the effect of smoking status on CL use.     

Immune profiling after minimally invasive lobectomy

ref="/pmc/articles/PMC8906716/figure/ivaa296-F6/" target="figure" rid-figpopup="ivaa296-F6" rid-ob="ob-ivaa296-F6">ref="/core/lw/2.0/html/tileshop_pmc/tileshop_pmc_inline.html?title=Click%20on%20image%20to%20zoom&p=PMC3&id=8906716_ivaa296f6.jpg" target="tileshopwindow" rel="noopener">rget="object" rel="noopener" href="/pmc/articles/PMC8906716/figure/ivaa296-F6/?report=objectonly">Open in a separate window OBJECTIVESWhether acute phase and immune responses are minimally affected following minimally invasive lung surgery needs further investigation. We performed a pilot study to evaluate the immune profile of patients who underwent video-assisted thoracoscopic surgery or robot-assisted thoracic surgery lobectomies for the treatment of suspicious or known stage I non-small-cell lung cancer.METHODSBlood samples were taken preoperatively and 3 and 24 h postoperatively were analysed for C-reactive protein, glucose, cortisol, tumour necrosis factor alpha (TNF-α), interleukin 8 (IL-8) and interleukin 10 (IL-10) levels. TNF-α, IL-8 and IL-10 were also measured in lung tissues. T (CD4, CD8), B (CD19) and natural killer (CD56, CD16) cell counts and natural killer cell functions were analysed using a flow cytometry-based assay before and after surgery.RESULTSMinimally invasive surgery (robot-assisted thoracic surgery + video-assisted thoracoscopic surgery) significantly decreased IL-10 (P = 0.016) levels after surgery. No significant differences were detected in TNF-α (P = 0.48) and IL-8 (P = 0.15) levels before and after surgery. C-reactive protein (P < 0.001), cortisol (P < 0.001) and glucose levels (P < 0.001) increased significantly after surgery. Lymphocyte, total T cell, CD3⁺CD4⁺ and CD3⁺CD8⁺ CD16⁺CD56⁺ cell counts were significantly lower on postoperative day 1.CONCLUSIONThere seems to be a dynamic balance between pro- and anti-inflammatory cytokines and immune cells following minimally invasive lobectomy.     

The Assessment of the Quality of Life in Children with Chronic Liver Disease

Background: Improvement in the quality of life (QoL) of patients with chronic diseases is as important as medical care. This study aimed to evaluate the QoL of children with chronic liver diseases and to determine related factors.Methods: For this study, 101 children with chronic liver disease, 100 healthy controls, and their parents were included. The Pediatric Quality of Life Scale (PedsQL) was used to evaluate health-related QoL; higher scores indicate better QoL. Patients were evaluated before and after initiation of treatment and being educated about their illness.Results: The mean patient age was 12.9 ± 3.9 years. Total PedsQL scores of the patients and the healthy control group were 38.6 ± 18.9 and 55.4 ± 14.3, respectively (P = .01). The scores of the parents of the patient and control groups were 35.4 ± 14.2 and 54.0 ± 16.9, respectively (P = .02). Patient and parent scores were positively correlated. Significantly higher scores were found in the 5-10 age group compared to the 10-15 and 15-18 age groups in the psychosocial score category. An increase in the QoL scores of patients who were started on medication other than steroid treatment was observed in the sixth month of treatment (35.8 ± 13.4 vs. 33.6 ± 8.9, P = .01, respectively).Conclusion: Both children with chronic liver diseases and their parents have a perceived lower QoL than healthy peers. The effect of chronic liver disease on psychosocial health is more pronounced in children older than 10 years. The quality of life is inversely proportional to the severity of the disease. It was observed that primary or symptomatic treatments have a positive impact on the perception of QoL, with the exception of steroid treatment.     

The effects of isotretinoin therapy on the biliary system

The aim of the present study was to investigate the potential effects of isotretinoin on the biliary system in patients with acne vulgaris receiving isotretinoin therapy. This was a preliminary retrospective study involving 40 patients with severe acne vulgaris who attended the dermatology clinic and were administered different doses (20 or 30 mg/day) of isotretinoin. Serum levels of AST, ALT, ALP, GGT, total bilirubin, direct bilirubin, and indirect bilirubin at the beginning and at the first month of therapy were scanned, recorded, and statistically analyzed. Total and indirect bilirubin levels at the first month of treatment in 30 patients, receiving isotretinoin at a dose of 20 mg/day, were significantly lower compared to the baseline values (p = .02 and p = .03, respectively), whereas AST and GGT serum levels were significantly higher (p = .003 and p = .006 respectively). No significant reduction in total and indirect bilirubin levels was detectable at the first month of treatment in 10 patients receiving isotretinoin at a dose of 30 mg/day; however, AST, ALP, and GGT levels were significantly elevated in these patients (p = .023; p = .004; and p = .001, respectively). To our knowledge, there is no previous study investigating the effects of isotretinoin on the biliary system, and, therefore, the present study is a preliminary one. Our findings implicate that low dose (20 mg/day) isotretinoin therapy can potentially reduce total and indirect bilirubin levels. Long‐term, large‐scale, prospective studies with patients receiving different doses of isotretinoin may provide more reliable information regarding the bilirubin lowering effects of isotretinoin and optimum dosing for achieving this clinical effect.     

Schwann cells as underestimated,major players in human skin physiology and pathology

Schwann cells (SCs) have long been recognized for their ability to support repair and promote axon regeneration following injury to the peripheral nervous system. In response to nerve injury, they rapidly dedifferentiate into a precursor-like state, secrete an array of inflammatory mediators and growth factors, proliferate, undergo epithelial-to-mesenchymal-like transformation to facilitate migration, phagocytose cellular debris and remodel the extracellular environment to promote regeneration of axons through the site of injury. However, even though a cutaneous role for SCs is becoming increasingly recognized, we argue in this Viewpoint essay that the likely complex functions of SCs in skin physiology and pathology beyond skin sensation and nerve repair deserve more attention and systemic research than they have received so far. For example, SCs promote wound healing, disseminate infection in leprosy, support the growth of neurofibromas/schwannomas and facilitate/accelerate the growth and invasion of melanoma. Despite representing a major dermal cell population, comparatively little is still known about the role of SCs in other dermatoses. To quintessentially illustrate the opportunities that promise to arise from a new skin research focus on SCs, we focus on two dermatoses that are not traditionally associated with SCs, that is, psoriasis and atopic dermatitis (AD), since both show distinct SC changes along with continuous nerve fibre degeneration and regeneration, and an impact of denervation on skin lesions. Specifically, we critically discuss the hypothesis that repeated activation of the SC repair programme occurs in and contributes to psoriasis and AD and delineate experimental approaches how to probe this clinically relevant hypothesis.