Engineering Chemo-Mechanical Properties of Zn Surfaces via Alucone Coating

Aqueous zinc (Zn)-ion batteries (AZIB) are promising candidates for the next-generation energy store systems due to their high capacity and low cost. Despite their nominal performance, Zn anodes tend to rapidly develop dendrite and fracture, leading to substantial capacity loss and cycling stability failure. Well-controlled coating using organic-inorganic hybrid molecules is highly promising to substantially improve their chemo-mechanical stability without compromising their performance. We herein present a critical assessment of the chemical and mechanical stability of alucone-coated Zn surfaces using first-principles simulations. Negative adsorption energies indicate strong cohesive strengths between alucone and the selected Zn surfaces. Energetically favorable alucone coatings are further verified by charge transfer at interfaces as seen through Bader charge analysis. Negative surface stress profiles at alucone coated interface are mostly responsible for surface reconstruction. The contributions of surface elastic constants are dependent on the selection of slip planes and the thickness of the thin film. By considering plane stress conditions, we calculate the mechanical properties which indicate the ductility of the alucone-coated basal thin film

Short-ranged ordering for improved mean-field simulation of disordered media: insights from refractory-metal high-entropy alloy carbonitrides

Multi-principal element materials (MPEMs) have been attracting a rapidly growing interest due to their exceptional performance under extreme conditions, from cryogenic conditions to extreme-high temperatures and pressures. Despite the simple conceptual premise behind their formation, computational high-throughput first-principles design of such materials is extremely challenging due to the large number of realizations required for sufficient statistical sampling of their design space. Furthermore, MPEMs are also known to develop short-ranged orderings (SROs) which can play a significant role in their stability and properties. Here, we present an expedient and efficient first-principles computational framework for assessing the compositional and mechanical properties of MPEMs, including SRO effects. This heuristic methodology systematically corrects phase-averaged free-energies of MPEMs to include SRO phases, while imposing constraints for materials design. To illustrate the methodology, we study the stability and mechanical properties of equi-molar refractory-metal high-entropy alloy carbonitrides (RHEA-CNs) such as ZrNbMoHfTaWC3N3. We show that SRO, arising due to preferential neighboring among refractory metals, is necessary for thermodynamic and mechanical stability and to satisfy the imposed design criteria, leading to complex compositions for which their molar fraction and mechanical properties are predicted.Comment: 7 pages, 4 figures, and 1 table. Supplemental Material of 20 pages, 10 figures, and 4 tables. 17M

Yüksek çözünürlüklü uydu görüntülerinin geometrik doğruluk yönünden incelenmesi

The high quality level that high resolution satellite images have reached in the last years has proved that these images could be a useful data source for the production of orthophoto images and different mapping products. Specifically, it is very important in areas where aerial photogrammetry is not possible or feasible due to political reasons / restrictions and mapping frequency constrained by the limits of flight planning. Research activities about high resolution satellite images have been mainly focusing on the geometric accuracy aspects in ortho-image generation and Digital Elevation Model (DEM) extraction. In addition to these activities, some researches are increasingly concentrating on feature detection, recognition and reconstruction studies like automated mapping of roads, extraction of 3D buildings and cadastral mapping. There are two important criteria for quality assessment of the images; geometric accuracy and object definition. When we take the mapping processes into consideration, these criteria are basically dependent on the relation between pixel size and the map scale, contrast information (spectral range and colour), atmosphere and the sun elevation, the printing technology and the resolution of the human eye in a usual reading distance. A study has been implemented in Gölbaşı near Ankara, which has 10 km X 10 km area and a height difference about 440 m, for geometric accuracy assessment of high resolution satellite images. 12 ground control points were revised and signalized before the recording of images. Stereo-pair Ikonos (dated August 4th, 2002) and mono Quickbird (dated May 26th, 2002) images and 1/16000 scaled aerial photographs (dated August 29th, 2002) have been provided by Inta (Turkey), Eurimage (Italy) and General Command of Mapping (Turkey) free of charge. For geometric accuracy assessment; different digital elevation models (DEM’s) have been created using photogrammetric and cartographic methods. Photogrammetric DEM has been produced using 1/16000 scaled stereo aerial photographs and has accuracy about 1 m. From the other side, cartographic DEM has been produced digitizing map contours and has accuracy about 5 m. And lastly, Ikonos DEM has been produced from stereo-pair Ikonos images automatically and has accuracy about 2 m. With these models, various orthophoto and mosaic images have been produced using ground control points. Used ground control points have had different distributions and number of points between 0 and 11. Well-recognized 27 checkpoints such as road junctions and field corners have been selected and measured with GPS. Planimetric coordinates of the checkpoints were measured on all orthophoto, mosaic and stereo images. These coordinates have been compared with GPS coordinates. From the comparison of these measurements, the differences and also the errors have been obtained. Afterwards the gross error positions have been evaluated according to ground control points’ network. The geometric accuracy results show that IKONOS - DEM can be used instead of photogrammetric DEM, the quality of GCP’s is as important as the number of GCP’s, systematic errors have occured in the easting / north easting (across track) direction and IKONOS images have better accuracy than Quickbird images when using direct sensor orientation parameters. Also we can say that the high resolution satellite images can be used in mid / large also from 1/6000 to 1/10000 scale map productions and these results are harmonious with the examples given in the literature. Actually there is nearly a consensus among photogrammetry and remote sensing society that some mapping applications from high resolution space imagery can be realized in mid / large scale. In addition, in spite of increasingly concentrating by some researches on feature detection, recognition and reconstruction studies in high resolution satellite images, it can not be said that these images couldn’t reach to the level of aerial images in determining and identifying of small features in big scale maps (e.g. 1/5000) yet. Therefore the discussions about usage of high resolution space imagery in big scaled map production are still lasting.  Keywords: High resolution, satellite images, orthophoto, control point, Digital Elevation Model (DEM).Yüksek çözünürlüklü uydu görüntülerinin son yıllarda eriştiği üstün kalite düzeyi, bu verilerin ortofoto görüntüler ve farklı haritacılık üretimleri konusunda iyi bir veri kaynağı olabileceğini kanıtlamıştır. Ancak günümüzde halen, yüksek çözünürlüklü uydu görüntülerinin büyük ölçekli harita üretim çalışmalarında kullanılabilmesine ilişkin tartışmalar sürmektedir. Bu nedenle, yüksek çözünürlüklü uydu görüntülerinin geometrik doğruluk yönünden incelenmesi amacıyla, 10 km x 10 km boyutlarında bir alana ve 440 m yükseklik farkına sahip olan Ankara yakınlarındaki Gölbaşı bölgesinde bir çalışma gerçekleştirilmiştir. Bu çalışma için 12 adet Yer Kontrol Noktası (YKN) tespit edilmiş ve görüntü alımından önce bu noktalar işaretlenmiştir. Daha sonra stereo Ikonos (4 Ağustos 2002 tarihli) ve mono Quickbird görüntüleri ile 1/16000 ölçekli stereo hava fotoğrafları (29 Ağustos 2002 tarihli)  temin edilmiştir. Geometrik doğruluk çalışması için öncelikle fotogrametrik ve kartografik yöntemler ile Ikonos uydu görüntülerinden Sayısal Yükseklik Modelleri (SYM) elde edilmiş ve farklı sayı ve dağılımda bulunan YKN kullanılarak değişik özelliklere sahip ortofotolar üretilmiştir. Arazide belirgin olarak tespit edilebilen 27 adet bağımsız kontrol noktası (test noktası) seçilmiş ve bunların koordinatları GPS ile arazide ölçülmüştür. Bağımsız kontrol noktalarının GPS koordinatları, aynı noktaların tüm ortofoto görüntüler üzerinde okunan koordinatları ile karşılaştırılmış ve aradaki farklar belirlenmiştir. Geometrik doğruluk araştırmaları sonucunda yapılan değerlendirmeler, yüksek çözünürlüklü uydu görüntülerinin orta/büyük ölçekli (1/6000–1/10000) harita üretim çalışmalarında kullanılabileceğini göstermektedir. Anahtar Kelimeler: Yüksek çözünürlük, ortofoto, kontrol noktası, Sayısal Yükseklik Modeli (SYM)

Prealbumin is a more sensitive marker than albumin to assess the nutritional status in patients undergoing radiotherapy for head and neck cancer

AIM OF THE STUDY: The aim of this prospective study was to determine the prevalence of malnutrition and to evaluate a more sensitive marker to assess the nutritional status in patients undergoing RT for head and neck cancer. MATERIAL AND METHODS: The prospective study included 51 (mean age of 57.6 ±11.2 years) patients undergoing RT for head and neck cancer. Malnutrition was defined as weight loss > 5% of baseline. RESULTS: Forty-six (90.2%) of 51 patients were male. Malnutrition developed in 33 (64.7%) patients during RT. Mean prealbumin level was significantly lower in patients with malnutrition than in those without malnutrition (17 ±5 g/dl vs. 22 ±5 g/dl, respectively, p = 0.004). On the other hand, there was no significant difference between the two groups in terms of other nutrition parameters including total protein, albumin, total cholesterol, triglyceride, and glucose (p > 0.05). The percentage of weight loss negatively correlated with prealbumin (r = –0.430, p = 0.002), but not with other nutrition parameters including total protein, albumin, triglyceride, total cholesterol, HDL cholesterol, LDL cholesterol, and glucose (p > 0.05). CONCLUSIONS: The prevalence of malnutrition was high in patients with head and neck cancer. Prealbumin was a more sensitive marker than albumin to assess the nutritional status in these patients

Management of single double-J stent failure in malignant ureteral obstruction: tandem ureteral stenting with less frequent stent exchange

PURPOSETo evaluate the safety and efficacy of the placement and exchange of tandem ureteral stents (TUS) under fluoroscopic guidance in the management of indwelling single double-J stent (DJS) failure in patients with malignant ureteral obstruction. We also aimed to investigate whether the generally accepted exchange period of DJSs could be extended using TUS.METHODSThis retrospective study involved 11 patients (10 female) with an age range of 27–64 years, median of 49 years, who underwent TUS (ipsilateral two 8F DJSs) placement due to indwelling single DJS failure occurring in less than 3 months. TUS exchanges were performed initially at 6-month intervals, and subsequent exchange intervals were extended to 9 and 12 months for seven patients. The interval from initial TUS placement to percutaneous nephrostomy, repeat exchange, or death was defined as the duration of stent patency.RESULTSIndwelling single DJS failure occurred during a median follow-up of 45 days (range, 35–60 days) in 14 ureters of 11 patients. TUS were successfully placed and exchanged with a technical success rate of 100% without any early major complications. Thirty-nine procedures (11 placement and 28 exchange procedures) in 55 ureters were performed. The median duration of urinary patency was significantly higher with TUS [300 days (range, 60–440 days)] compared with single DJSs [45 days (range, 35–60 days)] (P < 0.001).CONCLUSIONThe placement and exchange of TUS can be safely and effectively performed under fluoroscopic guidance. The need for frequent DJS exchange could be reduced with increased duration of stent patency using TUS

Diaqua­bis(1,3-propane­diamine)nickel(II) squarate tetrahydrate

The asymmetric unit of the title compound, [Ni(C3H10N2)2(H2O)2](C4O4)·4H2O, contains one-half of the diaqua­bis(1,3-propane­diamine)nickel(II) cation, one-half of the centrosymmetric squarate anion and two uncoordinated water mol­ecules. In the cation, the NiII atom is located on a crystallographic inversion centre and has a slightly distorted octa­hedral coordination geometry. The six-membered chelate ring adopts a chair conformation. O—H⋯O hydrogen bonds link the cation and anion through the water mol­ecule, while N—H⋯O hydrogen bonds link the cation and anion and cation and water mol­ecules. In the crystal structure, inter­molecular O—H⋯O and N—H⋯O hydrogen bonds link the mol­ecules into a three-dimensional network structure

Electric Field Tunability of Photoluminescence from a Hybrid Peptide-Plasmonic Metal Microfabricated Chip

Enhancement of fluorescence through the application of plasmonic metal nanostructures has gained substantial research attention due to the widespread use of fluorescence-based measurements and devices. Using a microfabricated plasmonic silver nanoparticle-organic semiconductor platform, we show experimentally the enhancement of fluorescence intensity achieved through electro-optical synergy. Fluorophores located sufficiently near silver nanoparticles are combined with diphenylalanine nanotubes (FFNTs) and subjected to a DC electric field. It is proposed that the enhancement of the fluorescence signal arises from the application of the electric field along the length of the FFNTs, which stimulates the pairing of low-energy electrons in the FFNTs with the silver nanoparticles, enabling charge transport across the metal-semiconductor template that enhances the electromagnetic field of the plasmonic nanoparticles. Many-body perturbation theory calculations indicate that, furthermore, the charging of silver may enhance its plasmonic performance intrinsically at particular wavelengths, through band-structure effects. These studies demonstrate for the first time that field-activated plasmonic hybrid platforms can improve fluorescence-based detection beyond using plasmonic nanoparticles alone. In order to widen the use of this hybrid platform, we have applied it to enhance fluorescence from bovine serum albumin and Pseudomonas fluorescens. Significant enhancement in fluorescence intensity was observed from both. The results obtained can provide a reference to be used in the development of biochemical sensors based on surface-enhanced fluorescence.Science Foundation IrelandEuropean Regional Development Fund (ERDF)Sustainable Energy Authority of Ireland (SEAI