Wound Healing Attributes of Polyelectrolyte Multilayers Prepared with Multi‐l‐arginyl‐poly‐l‐aspartate Pairing with Hyaluronic Acid and γ‐Polyglutamic Acid

Biodegradable multi‐l ‐arginyl‐poly‐l ‐aspartate (MAPA), more commonly cyanophycin, prepared with recombinant Escherichia coli contains a polyaspartate backbone with lysine and arginine as side chains. Two assemblies of polyelectrolyte multilayers (PEMs) are fabricated at three different concentration ratios of insoluble MAPA (iMAPA) with hyaluronic acid (iMAPA/HA) and with γ‐polyglutamic acid (iMAPA/γ‐PGA), respectively, utilizing a layer‐by‐layer approach. Both films with iMAPA and its counterpart, HA or γ‐PGA, as the terminal layer are prepared to assess the effect on film roughness, cell growth, and cell migration. iMAPA incorporation is higher for a higher concentration of the anionic polymer due to better charge interaction. The iMAPA/HA films when compared to iMAPA/γ‐PGA multilayers show least roughness. The growth rates of L929 fibroblast cells on the PEMs are similar to those on glass substrate, with no supplementary effect of the terminal layer. However, the migration rates of L929 cells increase for all PEMs. γ‐PGA incorporated films impart 50% enhancement to the cell migration after 12 h of culture as compared to the untreated glass, and the smooth films containing HA display a maximum 82% improvement. The results present the use of iMAPA to construct a new layer‐by‐layer system of polyelectrolyte biopolymers with a potential application in wound dressing.     

A new arithmetic criterion for graphs being determined by their generalized Q-spectrum

“Which graphs are determined by their spectrum (DS for short)?” is a fundamental question in spectral graph theory. It is generally very hard to show a given graph to be DS and few results about DS graphs are known in literature. In this paper, we consider the above problem in the context of the generalized $Q$-spectrum. A graph $G$ is said to be determined by the generalized $Q$-spectrum (DGQS for short) if, for any graph $H$, $H$ and $G$ have the same $Q$-spectrum and so do their complements imply that $H$ is isomorphic to $G$. We give a simple arithmetic condition for a graph being DGQS. More precisely, let $G$ be a graph with adjacency matrix $A$ and degree diagonal matrix $D$. Let $Q=A+D$ be the signless Laplacian matrix of $G$, and $W_Q\left(G\right)=[e,Qe,\dots ,Q^{n-1}e]$ ($e$ is the all-ones vector) be the $Q$-walk matrix. We show that if $\frac{det{W}_Q\left(G\right)}{2^{\lfloor \frac{3n-2}{2}\rfloor }}$ (which is always an integer) is odd and square-free, then $G$ is DGQS.     

On a sufficient condition for a Fano manifold to be covered by rational N-folds

In this paper, we prove a conjecture by T. Suzuki, which says if a smooth Fano manifold satisfies some positivity condition on its Chern characters, then it can be covered by rational N-folds. We prove this conjecture by using purely combinatorial properties of Bernoulli numbers.     

地下水脆弱性风险预警和评估的区间三角模糊多属性决策模型

应用基于逼近理想解排序法的区间三角模糊多属性决策模型,对三江平原六大分区地下水脆弱性进行了风险预警和评估.评估结果与前人吻合,可为有关决策部门采取相应降低环境风险的措施提供参考.实例验证表明,模型具有更高的计算精度和更好的评价效果,为有关环境风险决策部门对地下水风险预警和评估提供了新的思路和方法.     

Hydrogen‐Bonded Films for Zero‐Order Release of Leuprolide

Leuprolide has been widely used in androgen deprivation therapy for the treatment of advanced prostate cancer, but its use is still limited due to its short half‐life. Herein, hydrogen‐bonded layer‐by‐layer films are fabricated from PEGylated leuprolide (PEG‐LEU) and tannic acid (TA). Because of its dynamic nature, the film disintegrates gradually in water and releases PEG‐LEU and TA. The in vitro release profile indicated perfect zero‐order kinetics, which is explained by the unique release mechanism. When implanted subcutaneously in male rats, the films maintain a constant serum drug level. For a 60‐bilayer film, the serum drug level is maintained constant for ≈24 days. No initial burst release is observed, suggesting that the in vivo release also follows zero‐order kinetics. Initially, an increase in the level of serum testosterone is induced by the released drug, followed by testosterone suppression to a constant level below the castrate level, which could be maintained as long as a constant serum drug level is maintained. Since the new drug carriers avoid an initial burst release of the drug and maintain a constant serum drug level and hence a constant serum testosterone level below the castrate level, these carriers are highly promising for androgen deprivation therapy.     

From Molecular Conformation to Phospholipid Bilayer Organization

Abstract

The structure and the dynamics of D-erythrostearoyl sphingomyelin has been studied by the variable temperature wide-line ³¹P and high-resolution ¹C CP MAS NMR apectroscopy. The results indicate the formation of the highly ordered, relaxed gelphase, and are interpreted based on the conformation of D-erytgrosphingomylin in the unaggregated state.     

RADIATION CHEMISTRY OF AMINOALKYITHIOIS

Abstract

Radiation chemistry of aminoalkylthiols and some derivatives (aminoalkyl-S-thiophosphates and aminoalkyl-S-thiosulfates among which are most effective radioprotectors) in aqueous solutions has been studied in order to establish the relation between the structure of these compounds and their radiation-chemical properties. Increase in the number of methylene groups between the sulfur atom and nitrogen atom in the aminothiol molecule from 2 to 4 and substitution of the amino group hydrogene by an alkyl radical has been found to be without appreciable effect both on the “spectra” of radiolisis products and rate constants for interaction of H, e^? _aq and OH with aminothiols     

微水导激光切割玻璃的耦合装置设计

为了解决激光切割钢化玻璃过程中由于热应力导致产生裂纹并发生破裂的技术难题，建立了光液耦合模型，采用FLUENT软件进行了耦合腔内多场分析，获得了微水导激光切割钢化玻璃的工艺参量。结果表明，在喷口口径为0.4mm、水束压力为20MPa、激光功率为48W、切割速率为20mm/s的工艺条件下，厚度为0.5mm及1.0mm的玻璃试样的切割表面均比较光滑、基体内无微裂纹存在，切缝宽度约为100μm。该双注水口耦合装置的设计是合理的，能够满足钢化玻璃切割工艺的要求。