Mechanical regulation of cardiac development

Mechanical forces are essential contributors to and unavoidable components of cardiac formation, both inducing and orchestrating local and global molecular and cellular changes. Experimental animal studies have contributed substantially to understanding the mechanobiology of heart development. More recent integration of high-resolution imaging modalities with computational modeling has greatly improved our quantitative understanding of hemodynamic flow in heart development. Merging these latest experimental technologies with molecular and genetic signaling analysis will accelerate our understanding of the relationships integrating mechanical and biological signaling for proper cardiac formation. These advances will likely be essential for clinically translatable guidance for targeted interventions to rescue malforming hearts and/or reconfigure malformed circulations for optimal performance. This review summarizes our current understanding on the levels of mechanical signaling in the heart and their roles in orchestrating cardiac development

Changes in Summer Irrigated Crop Area and Water Use in Southeastern Turkey from 1993 to 2002: Implications for Current and Future Water Resources

Changes in summer irrigated cropland acreage and related water use are estimated from satellite remote sensing and ancillary data in semi-arid Southeastern Turkey where traditionally dry agricultural lands are being rapidly transformed into irrigated fields with the help of water from the Euphrates-Tigris Rivers. An image classification methodology based on thresholding of Landsat NDVI images from the peak summer period reveals that the total area of summer irrigated crops has increased three-fold (from 35,000 ha to over 100,000) in the Harran Plain between 1993 and 2002. Coupled analysis of annual irrigated crop area from remote sensing and potential evapotranspiration based estimates of irrigation water requirements for cotton indicate a corresponding increase in agricultural water use from about 370 million cubic meters to over one billion cubic meters, a volume in accordance with the state estimates. These estimates have important implications for understanding the rapid changes in current agricultural withdrawals in Southeastern Turkey and form a quantitative basis for exploring the changes in future water demands in the region. For example, expansion of irrigated lands have led to a steady decrease in potential evaporation due to increased roughness and decreased humidity deficit in the Harran Plain. Assuming that the changes in future evaporation conditions will be of similar nature, water use for irrigation is expected to decrease over 40 percent in future irrigation sites. Incorporating this decrease in overall planning of the irrigation projects currently under construction should lead to improved management, and by extension, sustainability of water resources in the region

The healing effects of the topical mesenchymal stem cells application on colonic anastomosis subjected to ischemia reperfusion injury

Intestinal ischemia reperfusion injury (IRI) is a challenging problem and it adversely affects the healing of colonic anastomosis. Our experimental study aimed to investigate the role of mesenchymal stem cells (MSC) administration in the healing of colonic anastomosis. A total of 33 rats were grouped as Control, IRI and MSC treatment groups. Three rats were reserved for obtaining MSCs. Colonic resection and anastomosis procedure was performed in all groups. Anastomotic line was wrapped with MSCs impregnated spongostan after colonic anastomosis in the rats of the MSC treatment group. All rats were sacrificed and anastomotic line were sampled for examination on the post operative seventh day. Tissue hydroxyproline (HP) levels and anastomotic bursting pressures were statistically compared. Anastomotic bursting pressures were found to be significantly high in MSC treatment group rats. The lowest anastomotic bursting pressure was detected in IRI group rats. Hydroxyproline content of the anastomotic sites were also found to be significantly higher in the rats of the MSC treatment group when compared with the IRI group rats. Our study showed that the detrimental effects of IRI on the healing process of colonic anastomosis in an experimental model may be alleviated with the treatment of MSCs. © 2021, Veteriner Fakultesi Dergisi. All rights reserved

Origins of Chevron Rollovers in Non-Two-State Protein Folding Kinetics

Chevron rollovers of some proteins imply that their logarithmic folding rates are nonlinear in native stability. This is predicted by lattice and continuum G\=o models to arise from diminished accessibilities of the ground state from transiently populated compact conformations under strongly native conditions. Despite these models' native-centric interactions, the slowdown is due partly to kinetic trapping caused by some of the folding intermediates' nonnative topologies. Notably, simple two-state folding kinetics of small single-domain proteins are not reproduced by common G\=o-like schemes.Comment: 10 pages, 4 Postscript figures (will appear on PRL

Two new records of leaf pathogenic fungi in Turkey

Abstract Rhytisma salicinum, a parasitic species on Salix caprea and Salix cinerea, and Septogloeum thomasianum, a parasitic species on Euonymus latifolius subsp. cauconis, are recorded for the first time from Turkey

The effect of RRA treatment on the mechanical properties of 7075 alloy

Bu çalışmada 0.85 mm kalınlığındaki 7075 kalite aluminyum alaşımı sacın, sertlik, mukavemet ve darbe direnci gibi mekanik özelliklerine, retrogresyon ve yeniden yaşlandırma ısıl işleminin etkisi incelenmiştir. Başlangıçta T6 temper durumunda olan alaşıma, 220°C’de 15 saniye – 60 dakika arasında retrogresyon uygulanmış, yeniden yaşlandırma 120°C’de 24 saat süreyle yapılmıştır. Retrogresyon ve yeniden yaşlandırma işlemi sonunda, sertlik önce artarak en yüksek değerine ulaşmış, daha uzun retrogresyon sürelerinde ise azalmıştır. Akma ve çekme mukavemeti ise retrogresyon süresine bağlı olarak azalırken, kopma uzaması ve darbe direncinde, retrogresyon süresine bağlı olarak sürekli bir artış görülmüştür. Sonuç olarak, retrogresyon ve yeniden yaşlandırma ısıl işlemiyle, belirli retrogresyon sürelerinde, T6 temper durumu seviyesine eşit ya da daha yüksek sertlik, mukavemet, süneklik ve tokluk elde edilmiştir.Anahtar Kelimeler: Aluminyum, retrogresyon ve yeniden yaşlandırma, çökelme sertleşmesi.In this study, the effect of retrogression and reageing heat treatment on mechanical properties such as hardness, strength and impact resistance of 0.85 mm thick 7075 quality aluminium alloy sheet has been investigated. The alloy, which was initially in T6 temper condition, was retrogressed at 220°C for various times between 15 seconds and 60 minutes, prior to reageing at 120°C for 24 hours. Hardness and electrical conductivity were monitored as an indicator of the microstructural changes during retrogression or reageing stages. Hardness was initially decreased giving a minimum as the retrogression time increases. Further retrogression times beyond increment in hardness resulted in a decrement of hardness again. Electrical conductivity was progressively increased as the retrogression time increased. Hardness of retrogressed and reaged samples initially increased as the retrogression time increased, exhibiting their maximum values, then finally decreased. Yield and tensile strength progressively decreased while elongation at fracture and impact resistance increased with increasing retrogression time. It is concluded that, equal or higher values of hardness, strength, ductility and toughness than those of T6 temper can be obtained with retrogression and reageing heat treatment. Improvement in hardness can be attributed to the increased number of precipitates in retrogressed and reaged microstructure. On the other hand, higher values of impact resistance are accompanied with overageing, which commences in longer retrogression time.Keywords: Aluminium, retrogression and reageing, precipitation hardening

Effect of Hf addition on reciprocating wear performance of ZrN coatings

Bu çalışmada, ZrN ve (Zr, %12 Hf)N kaplamaların aşınma davranışları incelenmiştir. Kaplamalar Zr ve %21Hf alaşımlı Zr katotların kombinasyonu ile üretilmiştir. Üretilen kaplamaların aşınma deneyleri, karşılıklı kazımalı aşınma deney cihazında, 1.5 N sabit yük altında ve 0.02 mm/s deney hızında 10 mm çapındaki Al2O3 bilyenin numune yüzeylerine sürtünmesi ile gerçekleştirilmiştir. Deney sonrası numune yüzeyinde oluşan aşınma izleri, yüzey profilometresi yardımı ile incelenmiş ve deney sonuçları aşınma iz alanları ölçülerek mm2 cinsinden alan kaybına göre değerlendirilmiştir. Deney sonuçları, (Zr, %12 Hf)N kaplamanın ZrN kaplamaya göre daha az aşındığını ve Hf ilavesinin aşınmaya karşı direnci artırdığını  göstermiştir.Anahtar Kelimler: Kaplama, FBB, ZrN, Hf, aşınma.In this study, a commercial ZrN and new (Zr, Hf)N coatings by alloying ZrN with Hf were deposited on hardened AISI D2 quality cold work tool steel plates by arc PVD technique. The coatings were prepared using combination of two cathodes under the equvalent PVD process conditions. ZrN and (Zr, %12 Hf)N coatings were obtained by utilising two Zr cathodes and one Zr and one Zr+21% Hf cothodes, respectively. The characterisation of the coatings were made by Scanning Electron Microscopic (SEM) examinations, X-ray diffraction analyses (XRD), hardness and adhesion tests as well as roughness and thickness measurements. Hardness measurements were carried out ultramicrohardness tester with a Vickers pyramid indenter. The indentation procedure consisted of 60 steps, with a waiting period between consecutive steps of 1 s. During the tests, load (P)-indentation depth (h)-time (t) data were recorded. Hardness measurements were performed under constant load of 25 mN. In order to investigate adhesion properties of the ZrN and the (Zr, 12% Hf)N coatings, scratch tests were used. The coatings were scratched up to 100 N normal load by using 10 mm/min scratching speed and 100 N/min loading speed. The dry sliding wear behaviour of ZrN and (Zr,12%Hf)N were examined by a reciprocating wear tester in ambient atmoshper. Alloying of ZrN coating with 12% Hf did not change the hardness significantly, but achieved an improvement on adhesion strength and wear resistance.Keywords: Coating, PVD, ZrN, Hf, wear

Diagnostic value of combined serum biomarkers for the evaluation of liver fibrosis in chronic hepatitis C infection: A multicenter, noninterventional, observational study

Background/Aims: The hepatitis C virus (HCV) infection is important cause of chronic hepatitis. Liver biopsy is considered the gold standard for assessment of fibrosis but this procedure is an invasive procedure. We aimed to evaluate the diagnostic efficiency of non-invasive serum biomarkers, separately and in combinations, on liver fibrosis in treatment-naive chronic hepatitis C (CHC) patients. Materials and Methods: Two hundred and sixteen treatment-naive CHC patients were enrolled from 32 locations across Turkey in this open-labelled, non-interventional prospective observational study. FibroTest®, aspartate aminotransferase-to-platelet ratio index(APRI), aspartate aminotransferase and alanine aminotransferase ratio (AAR), fibrosis index based on four factors (FIB-4), Age-platelet(AP) index and Forns index were measured and compared with Metavir scores got from liver biopsies. Results: Data from 182 patients with baseline liver biopsy were suitable for analysis. One hundred and twenty patients (65.9%) had F0-F1 fibrosis and 62 patients (34.1%) had F2-F4 fibrosis. APRI 0.732 area under the curve(AUC) indicated advanced fibrosis with 69% sensitivity and 77% specificity. FIB-4 0.732 AUC and FibroTest 0.715 AUC indicated advanced fibrosis with 69% and 78.4% sensitivity, and 75% and 71.4% specificity, respectively. The combined use of tests also led to an increase in AUC and specificity. Combinations of FibroTest with APRI and/or FIB-4, and FIB-4 with APRI were optimal for the evaluation of liver fibrosis. Conclusion: Fibrotest, FIB-4, APRI, AP index and Forns index exhibit good diagnostic performance for determining liver fibrosis in CHC patients, and the use of at least two tests together will increase their diagnostic value still further. © Copyright 2018 by The Turkish Society of Gastroenterology

mmWave polarization diversity wideband multiple-input/multiple-output antenna system with symmetrical geometry for future compact devices

The fifth generation (5G) of mobile networks is a significant technological advancement in telecommunications that provides faster data speeds, lower latency, and greater network capacity. One of the key technologies that enables 5G is multiple-input/multiple-output (MIMO) antenna systems, which allow for the transmission and reception of multiple data streams simultaneously, improving network performance and efficiency. MIMO is essential to meeting the demand for higher data rates and improved network performance in 5G networks. This work presents a four-element MIMO antenna system dedicated to the upper 5G millimeter-wave (mmWave) spectrum. The suggested antenna system is designed using an ultra-thin RO5880 substrate having total dimensions of 20 x 20 x 0.254 mm(3) with symmetrical geometry. The proposed antenna covers a fractional bandwidth of 46.875% (25-38 GHz), covering potential 5G bands of 26, 28, and 32 GHz, and offers isolation of >18 dB. The proposed MIMO system is fabricated and tested in-house. The antenna showed efficiency >88% at the potential band of interest and a peak gain of 3.5 dBi. The orthogonal arrangement of the resonating elements provides polarization diversity. Also, the MIMO parameters obtained, such as mean effective gain (MEG), envelope correlation coefficient (ECC), diversity gain (DG), channel capacity loss (CCL), and total active reflection coefficient (TARC), are found to have good performance. The measured results obtained are found to be in good agreement with simulations, hence making the proposed MIMO antenna suitable for handheld mmWave 5G devices.Prince Sultan University, Riyadh, Saudi Arabi

Energetic Components of Cooperative Protein Folding

A new lattice protein model with a four-helix bundle ground state is analyzed by a parameter-space Monte Carlo histogram technique to evaluate the effects of an extensive variety of model potentials on folding thermodynamics. Cooperative helical formation and contact energies based on a 5-letter alphabet are found to be insufficient to satisfy calorimetric and other experimental criteria for two-state folding. Such proteinlike behaviors are predicted, however, by models with polypeptide-like local conformational restrictions and environment-dependent hydrogen bonding-like interactions.Comment: 11 pages, 4 postscripts figures, Phys. Rev. Lett. (in press