Snow metamorphism: a fractal approach

Snow is a porous disordered medium consisting of air and three water phases: ice, vapour and liquid. The ice phase consists of an assemblage of grains, ice matrix, initially arranged over a random load bearing skeleton. The quantitative relationship between density and morphological characteristics of different snow microstructures is still an open issue. In this work, a three-dimensional fractal description of density corresponding to different snow microstructure is put forward. First, snow density is simulated in terms of a generalized Menger sponge model. Then, a fully three-dimensional compact stochastic fractal model is adopted. The latter approach yields a quantitative map of the randomness of the snow texture, which is described as a three-dimensional fractional Brownian field with the Hurst exponent H varying as continuous parameter. The Hurst exponent is found to be strongly dependent on snow morphology and density. The approach might be applied to all those cases where the morphological evolution of snow cover or ice sheets should be conveniently described at a quantitative level

Assessing Deep Generative Models in Chemical Composition Space

The computational discovery of novel materials has been one of the main motivations behind research in theoretical chemistry for several decades. Despite much effort, this is far from a solved problem, however. Among other reasons, this is due to the enormous space of possible structures and compositions that could potentially be of interest. In the case of inorganic materials, this is exacerbated by the combinatorics of the periodic table since even a single-crystal structure can in principle display millions of compositions. Consequently, there is a need for tools that enable a more guided exploration of the materials design space. Here, generative machine learning models have recently emerged as a promising technology. In this work, we assess the performance of a range of deep generative models based on reinforcement learning, variational autoencoders, and generative adversarial networks for the prototypical case of designing Elpasolite compositions with low formation energies. By relying on the fully enumerated space of 2 million main-group Elpasolites, the precision, coverage, and diversity of the generated materials are rigorously assessed. Additionally, a hyperparameter selection scheme for generative models in chemical composition space is developed

Transversity and Collins functions from SIDIS and e+e- data

A global analysis of the experimental data on azimuthal asymmetries in semi-inclusive deep inelastic scattering (SIDIS), from the HERMES and COMPASS Collaborations, and in e+e- --> h1 h2 X processes, from the BELLE Collaboration, is performed. It results in the extraction of the Collins fragmentation function and, for the first time, of the transversity distribution function for u and d quarks. These turn out to have opposite signs and to be sizably smaller than their positivity bounds. Predictions for the azimuthal asymmetry A_{UT}^{sin(phi_h + phi_S)}, as will soon be measured at JLab and COMPASS operating on a transversely polarized proton target, are then presented

Semi-Inclusive Deep Inelastic Scattering processes from small to large P_T

We consider the azimuthal and $P_T$ dependence of hadrons produced in unpolarized Semi-Inclusive Deep Inelastic Scattering (SIDIS) processes, within the factorized QCD parton model. It is shown that at small $P_T$ values, P_T \lsim 1 GeV/c, lowest order contributions, coupled to unintegrated (Transverse Momentum Dependent) quark distribution and fragmentation functions, describe all data. At larger $P_T$ values, P_T \gsim 1 GeV/c, the usual pQCD higher order collinear contributions dominate. Having explained the full $P_T$ range of available data, we give new detailed predictions concerning the azimuthal and $P_T$ dependence of hadrons which could be measured in ongoing or planned experiments by HERMES, COMPASS and JLab collaborations.Comment: 14 pages, 17 figures, uses revtex

Erkek köpeklerde intratestiküler gliserol ve etanol uygulamalarının kısırlaştırma üzerine etkilerinin karşılaştırılması (Comporation of the Effects of Intratesticular Glycerol and Ethanol Injections on Sterilization of Male Dogs)

This study was conducted to investigate the effects of intratesticular glycerol and ethanol injection on sterilization. Twelve mature male dogs were used. They were allocated randomly to two equal groups called glycerol and ethanol and one ml glycerol (70%) and ethanol (95%) was injected intratesticularly. The animals were observed during two months. The blood and sperm samples obtained once a week in all groups were examined regarding to serum testosterone level and spermatozoon concentration and motility rate. There was a fistula formation and scrotal wounds resulting from orchitis in all glycerol and two ethanol group dogs after the 5th day of injection. The fistular openings closed spontaneously in all cases in due course. After the 2nd month, testicular atrophy was seen to occur. It was determined the presence of marked decreases (p<0.01) in both groups spermatozoon concentration and motility as well as in the level of serum testosterone two weeks after drug injection. The histopathologic examination conducted after the 2nd month revealed degeneration, necrosis and diffuse connective tissue proliferation in the seminiferus contortus tubulus of both groups. It has been concluded that glycerol and ethanol can be effective for sterilization in male dogs

Emergent versus delayed lithotripsy for obstructing ureteral stones: a cumulative analysis of comparative studies

Objective To analyze the current evidence on the use of ureteroscopy (URS) and extracorporeal shock wave lithotripsy (ESWL) for the management of obstructing ureteral stones in emergent setting. Methods A systematic literature review was performed up to June 2016 using Pubmed and Ovid databases to identify pertinent studies. The PRISMA criteria were followed for article selection. Separate searches were done using a combinations of several search terms: "laser lithotripsy", "ureteroscopy", "extracorporeal shock wave lithotripsy", "ESWL", "rapid", "immediate", "early", "delayed", "late", "ureteral stones", "kidney stones", "renal stones". Only titles related to emergent/rapid/immediate/early (as viably defined in each study) versus delayed/late treatment of ureteral stones with either URS and/or ESWL were considered for screening. Demographics and operative outcomes were compared between emergent and delayed lithotripsy. RevMan review manager software was used to perform data analysis. Results Four studies comparing emergent (n = 526) versus delayed (n = 987) URS and six studies comparing emergent (n = 356) versus delayed (n = 355) SWL were included in the analysis. Emergent URS did not show any significant difference in terms of stone-free rate (91.2 versus 90.9%; OR 1.04; CI 0.71, 1.52; p = 0.84), complication rate (8.7% for emergent versus 11.5% for delayed; OR 0.94; CI 0.65, 1.36; p = 0.74) and need for auxiliary procedures (OR 0.85; CI 0.42, 1.7; p = 0.85) when compared to delayed URS. Emergent ESWL was associated with a higher likelihood of stone free status (OR 2.2; CI 1.55, 3.17; p < 0.001) and a lower likelihood of need for auxiliary maneuvers (OR 0.49; CI 0.33, 0.72; p < 0.001) than the delayed procedure. No differences in complication rates were noticed between the emergent and delayed ESWL (p = 0.37). Conclusions Emergent lithotripsy, either ureteroscopic or extracorporeal, can be offered as an effective and safe treatment for patients with symptomatic ureteral stone. If amenable to ESWL, based on stone and patient characteristics, an emergent approach should be strongly considered. Ureteroscopy in the emergent setting is mostly reserved for distally located stones. The implementation of these therapeutic approaches is likely to be dictated by their availability.info:eu-repo/semantics/publishedVersio

Organometallic iridium(III) anticancer complexes with new mechanisms of action: NCI-60 screening, mitochondrial targeting, and apoptosis

Platinum complexes related to cisplatin, cis-[PtCl2(NH3)2], are successful anticancer drugs; however, other transition metal complexes offer potential for combating cisplatin resistance, decreasing side effects, and widening the spectrum of activity. Organometallic half-sandwich iridium (IrIII) complexes [Ir(Cpx)(XY)Cl]+/0 (Cpx = biphenyltetramethylcyclopentadienyl and XY = phenanthroline (1), bipyridine (2), or phenylpyridine (3)) all hydrolyze rapidly, forming monofunctional G adducts on DNA with additional intercalation of the phenyl substituents on the Cpx ring. In comparison, highly potent complex 4 (Cpx = phenyltetramethylcyclopentadienyl and XY = N,N-dimethylphenylazopyridine) does not hydrolyze. All show higher potency toward A2780 human ovarian cancer cells compared to cisplatin, with 1, 3, and 4 also demonstrating higher potency in the National Cancer Institute (NCI) NCI-60 cell-line screen. Use of the NCI COMPARE algorithm (which predicts mechanisms of action (MoAs) for emerging anticancer compounds by correlating NCI-60 patterns of sensitivity) shows that the MoA of these IrIII complexes has no correlation to cisplatin (or oxaliplatin), with 3 and 4 emerging as particularly novel compounds. Those findings by COMPARE were experimentally probed by transmission electron microscopy (TEM) of A2780 cells exposed to 1, showing mitochondrial swelling and activation of apoptosis after 24 h. Significant changes in mitochondrial membrane polarization were detected by flow cytometry, and the potency of the complexes was enhanced ca. 5× by co-administration with a low concentration (5 μM) of the γ-glutamyl cysteine synthetase inhibitor L-buthionine sulfoximine (L-BSO). These studies reveal potential polypharmacology of organometallic IrIII complexes, with MoA and cell selectivity governed by structural changes in the chelating ligands

A dietary carbohydrate–gut Parasutterella–human fatty acid biosynthesis metabolic axis in obesity and type 2 diabetes

Recent rodent microbiome experiments suggest that besides Akkermansia, Parasutterella sp. are important in type 2 diabetes and obesity development. In the present translational human study, we aimed to characterize Parasutterella in our European cross-sectional FoCus cohort (n = 1,544) followed by validation of the major results in an independent Canadian cohort (n = 438). In addition, we examined Parasutterella abundance in response to a weight loss intervention (n = 55). Parasutterella was positively associated with BMI and type 2 diabetes independently of the reduced microbiome α/β diversity and low-grade inflammation commonly found in obesity. Nutritional analysis revealed a positive association with the dietary intake of carbohydrates but not with fat or protein consumption. Out of 126 serum metabolites differentially detectable by untargeted HPLC-based MS-metabolomics, L-cysteine showed the strongest reduction in subjects with high Parasutterella abundance. This is of interest, since Parasutterella is a known high L-cysteine consumer and L-cysteine is known to improve blood glucose levels in rodents. Furthermore, metabolic network enrichment analysis identified an association of high Parasutterella abundance with the activation of the human fatty acid biosynthesis pathway suggesting a mechanism for body weight gain. This is supported by a significant reduction of the Parasutterella abundance during our weight loss intervention. Together, these data indicate a role for Parasutterella in human type 2 diabetes and obesity, whereby the link to L-cysteine might be relevant in type 2 diabetes development and the link to the fatty acid biosynthesis pathway for body weight gain in response to a carbohydrate-rich diet in obesity development