The residue field as a high syzygy

In this paper, we study commutative local rings whose residue field is a high syzygy. We are able to characterize such rings with embedding dimension at most 3 as those that are Artinian and Gorenstein.     

GRP78‐Targeted HPMA Copolymer‐Photosensitizer Conjugate for Hyperthermia‐Induced Enhanced Uptake and Cytotoxicity in MCF‐7 Breast Cancer Cells

Photodynamic therapy (PDT) is a promising cancer treatment approach. However, the photosensitizers (PS) used for PDT are often limited by their poor solubility and selectivity for tumors. The goal of this study is to improve water solubility and delivery of the photosensitizer 2‐[1‐hexyloxyethyl]‐2‐divinyl pyropheophorbide‐a (HPPH) to breast cancer cells. An N‐(2‐hydroxypropyl)methacrylamide (HPMA) copolymer–HPPH photosensitizer conjugate is synthesized with heat shock receptor glucose‐regulated protein 78 (GRP78), targeting to GRP78 receptors of MCF‐7 cells, which are upregulated under mild hyperthermia. It is found that the uptake of the GRP78 targeted pep‐HPMA‐HPPH copolymer conjugate in MCF‐7 cells is improved through heat induction. Under mild hyperthermia the targeted copolymers are more effective compared to free HPPH. These results show potential for the utility of mild hyperthermia and copolymer delivery vehicles to enhance the efficacy of photodynamic therapy.     

A Comparison Between Full-COLD PCR/HRM and PCR Sequencing for Detection of Mutations in Exon 9 of PIK3CA in Breast Cancer Patients

Applied Biochemistry and Biotechnology - One of the most common somatic mutations in breast cancer is found in PIK3CA with a prevalence rate of 18–45%. Different variants of this gene are...     

Axisymmetric wave propagation of thermoelastic transversely isotropic half-space under buried loading using potential functions

By virtue of a new scalar potential function and Hankel integral transforms, the wave propagation analysis of a thermoelastic transversely isotropic half-space is presented under buried loading and heat flux. The governing equations of the problem are the differential equations of motion and the energy equation of the coupled thermoelasticity theory. Using a scalar potential function, these coupled equations have been uncoupled and a six-order partial differential equation governing the potential function is received. The displacements, temperature, and stress components are obtained in terms of this potential function in cylindrical coordinate system. Applying the Hankel integral transform to suppress the radial variable, the governing equation for potential function is reduced to a six-order ordinary differential equation with respect to z. Solving that equation, the potential function and therefore displacements, temperature, and stresses are derived in the Hankel transformed domain for two regions. Using inversion of Hankel transform, these functions can be obtained in the real domain. The integrals of inversion Hankel transform are calculated numerically via Mathematica software. Our numerical results for displacement and temperature are calculated for surface excitations and compared with the results reported in the literature and a very good agreement is achieved.     

A quantitative study of sodium tungstate protective effect on pancreatic beta cells in streptozotocin-induced diabetic rats

Diabetes is a major public health problem. Development of new therapies that are able to improve glycemia management, cure diabetes, and can even protect from it, are of great interest. This study investigated the protective effect of sodium tungstate against STZ-induced beta-cell damages by means of stereological methods. Sixty rats were divided into six groups: control (C), tungstate-treated control (TC), STZ-induced diabetic (D), STZ-induced diabetic rats were treated by sodium tungstate from 1 week before STZ injection (TDB), food-restricted diabetic (FRD), and diabetic rats treated with sodium tungstate 1 week after STZ administration (TDA). Stereological estimation of pancreas volume, islets volume density, volume-weighted mean islets volume and mass of beta cells, islets, and pancreas and total number of islets were done. Islets volume density, volume-weighted mean islets volume, and mass of beta cells, islets, and pancreas of TDB group was significantly higher than D, FRD and TDA groups (P < 0.001) and was comparable to controls (C and TC groups). Total number of islets, pancreas wet weight and volume did not show any significant changes between these groups (P > 0.05).Results suggested that sodium tungstate preserves pancreatic beta cells from STZ-induced damages and diabetes induction in rats.     

Fabrication of smart cutting tools with embedded optical fiber sensors using combined laser solid freeform fabrication and moulding techniques

To realize the concept of smart tools, embedding of fiber optic sensors in the metallic structure of a cutting tool with combined laser solid freeform fabrication (LSFF) and moulding is presented in this paper. Metallic parts with embedded optical fiber sensors are capable of monitoring physical parameters like force and temperature. These sensors are advantageous relative to other conventional electric and electromagnetic sensors due to their light weight, immunity to external electromagnetic fields, small size, long-term durability, and long-range linearity. In the present work, the optical fibers (e.g., fiber Bragg grating sensor, single-mode fiber optics) are moulded under tensile forces within a mild steel casing filled by Sn–Pb to fabricate a protective layer around them. Afterwards, LSFF is utilized to deposit tungsten carbide reinforced in cobalt (WC–Co) on the surface of the mild steel component. The performance results, in which the sensor exposed to a light bandwidth, show that the maximum light power loss after embedding is about 21% implying that the fiber is not damaged during the embedding process. Also, the sensor output has a linear characteristic under compression loadings indicating that the debonding of the fiber from the protective layer is not probable. The produced samples are examined by scanning electron microscopy and X-ray diffraction to assess the physical properties of the tool. Microstructural images reveal no cracks and porosity around the fiber indicating a good bonding between the fiber and the surrounding media. Material characterizations of the manufactured tool are also discussed.     

Survey reactivity of 2-aminopyridine and Meldrum’s acid in the presence of aryl glyoxals or aryl aldehydes; ethyl 2-(3-aryl imidazo[1,2-a]pyridin-2-yl)acetates versus ethyl 3-aryl-3-(pyridin-2-ylamino)propanoates

Research on Chemical Intermediates - The aim of present investigation is survey reactivity of 2-aminopyridine and Meldrum’s acid in the presence of aryl glyoxals or aryl aldehydes. The ethyl...     

Exceedingly Facile Ph?X Activation (X=Cl,Br, I) with Ruthenium(II): Arresting Kinetics,Autocatalysis, and Mechanisms

[(Ph₃P)₃Ru(L)(H)₂] (where L=H₂ ( 1 ) in the presence of styrene, Ph₃P ( 3 ), and N₂ ( 4 )) cleave the Ph X bond (X=Cl, Br, I) at RT to give [(Ph₃P)₃RuH(X)] ( 2 ) and PhH. A combined experimental and DFT study points to [(Ph₃P)₃Ru(H)₂] as the reactive species generated upon spontaneous loss of L from 3 and 4 . The reaction of 3 with excess PhI displays striking kinetics which initially appears zeroth order in Ru. However mechanistic studies reveal that this is due to autocatalysis comprising two factors: 1) complex 2 , originating from the initial PhI activation with 3 , is roughly as reactive toward PhI as 3 itself; and 2) the Ph I bond cleavage with the just‐produced 2 gives rise to [(Ph₃P)₂RuI₂], which quickly comproportionates with the still‐present 3 to recover 2 . Both the initial and onward activation reactions involve PPh₃ dissociation, PhI coordination to Ru through I, rearrangement to a η²‐PhI intermediate, and Ph I oxidative addition.     

Large Tolerance of Lasing Properties to Impurity Defects in GaAs(Sb)-AlGaAs Core-Shell Nanowire Lasers

GaAs-AlGaAs based nanowire (NW) lasers hold great potential for on-chip photonic applications, where lasing metrics have steadily improved over the years by optimizing resonator design and surface passivation methods. The factor that will ultimately limit the performance will depend on material properties, such as native- or impurity-induced point defects and their impact on non-radiative recombination. Here, the role of impurity-induced point defects on the lasing performance of low-threshold GaAs(Sb)-AlGaAs NW-lasers is evaluated, particularly by exploring Si-dopants and their associated vacancy complexes. Si-induced point defects and their self-compensating nature are identified using correlated atom probe tomography, resonant Raman scattering, and photoluminescence experiments. Under pulsed optical excitation the lasing threshold is remarkably low (<10 µJ cm⁻²) and insensitive to impurity defects over a wide range of Si doping densities, while excess doping ([Si]>10¹⁹ cm⁻³) imposes increased threshold at low temperature. These characteristics coincide with increased Shockley-Read-Hall recombination, reflected by shorter carrier lifetimes, and reduced internal quantum efficiencies (IQE) . Remarkably, despite the lower IQE the presence of self-compensating Si-vacancy defects provides an improved temperature stability in lasing threshold with higher characteristic temperature and room-temperature lasing. These findings highlight an overall large tolerance of lasing metrics to impurity defects in GaAs-AlGaAs based NW-lasers.     

Single Peptide Backbone Surrogate Mutations to Regulate Angiotensin GPCR Subtype Selectivity

Mutating the side-chains of amino acids in a peptide ligand, with unnatural amino acids, aiming to mitigate its short half-life is an established approach. However, it is hypothesized that mutating specific backbone peptide bonds with bioisosters can be exploited not only to enhance the proteolytic stability of parent peptides, but also to tune its receptor subtype selectivity. Towards this end, four [Y]⁶-Angiotensin II analogues are synthesized where amide bonds have been replaced by 1,4-disubstituted 1,2,3-triazole isosteres in four different backbone locations. All the analogues possessed enhanced stability in human plasma in comparison with the parent peptide, whereas only two of them achieved enhanced AT₂R/AT₁R subtype selectivity. This diversification has been studied through 2D NMR spectroscopy and unveiled a putative more structured microenvironment for the two selective ligands accompanied with increased number of NOE cross-peaks. The most potent analogue, compound 2 , has been explored regarding its neurotrophic potential and resulted in an enhanced neurite growth with respect to the established agent C21.