Raman spectroscopy monitors adverse bone sequelae of cancer radiotherapy

Raman spectroscopy provides information on bone chemical composition and structure via widely used metrics including mineral to matrix ratio, mineral crystallinity and carbonate content, collagen crosslinking ratio and depolarization ratios. These metrics are correlated with bone material properties, such as hardness, plasticity and Young''s modulus. We review application of Raman spectroscopy to two important irradiated animalmodels: the mouse tibia, amodel for damage to cortical bone sites including the rib (breast cancer) and to healthy tissue adjacent to extremity sarcomas, and the rat mandible, a model for radiation damage in head and neck cancer radiotherapy. Longitudinal studies of irradiated mouse tibia demonstrate that radiation-induced matrix abnormalities can persist even 26 weeks postradiation. Polarized Raman spectroscopy shows formation of more ordered orientation of both mineral and collagen. At 8 weeks post-radiation, irradiated rat hemimandible exhibits transient hypermineralization, increased collagen cross-linking and decreased depolarization ratios of mineral and collagen. A standard radioprotectant, amifostine, mitigates rat mandible radiation damage, with none remaining detectable 18 weeks post-radiation. Already a powerful tool to monitor radiation damage, Raman spectroscopy may be important in development of new radiotherapy protocols and radioprotective agents. Further in vivo studies of radiation effects on the rodent models are underway, as are development of methodologies for eventual use in human subjects.     

Sensing behavior of BN nanosheet toward nitrous oxide: A DFT study

In order to develop a sensor for the detection of toxic N₂O molecules, the interaction of pristine and Aldoped BN nanosheets with an N₂O molecule was investigated using density functional theory calculations. It was found that unlike the pristine sheet, the Al-doped sheet can effectively interact with the N₂O molecule so that its electronic properties and conductivity are dramatically changed. Webelieve that replacing a B atom of the BN sheet with an Al atom may be a good strategy for improving the sensitivity of these nanosheets toward N₂O, which cannot be trapped and detected by the pristine sheet.     

Synergetic influence of ex-situ camphoric carbon nano-grafting on lithium titanates for lithium ion capacitors

The present study provides detailed experimental results on the synthesis and characterization of carbonized lithium titanate spinel(LTO) composites as electrode materials for lithium ion capacitor.The LTO particles were grafted with a porous carbon layer obtained from the pyrolysis of camphor.The graphitic nature of the carbon was confirmed through Raman spectroscopy.The relative contributions from the capacitive and diffusion controlled processes underlying these electrodes were mathematically modeled.Electron transport mechanism underlying these electrodes was determined by measuring the work functions(φ) of LTO and carbon grafted LTO using ultraviolet photoelectron spectroscopy.These carbon grafted LTO composites exhibited an energy density of 330 m Wh L-1and a peak power density of 2.8 k W L-1,when employed as electrodes in coin cells with excellent cycling stability at the end of 4000 cycles.     

One pot three component synthesis of spiro [indolo-3,10’-indeno[1,2-b]quinolin]-2,4,11’-triones as a new class of antifungal and antimicrobial agents

A simple and efficient three component procedure has been developed for the synthesis of highly substituted spiro[indolo-3,10'-indeno[1,2-b]quinolin]-2,4,11'-triones by one pot three component condensation of enaminones, isatin and indane-1,3-dione in ethanol:water (1:1) in presence of ceric ammonium nitrate (CAN) as catalyst. This method provides several advantages such as lesser reaction time, high yield of products and operational simplicity. The antimicrobial activity of some of the compounds has been investigated against six microbial strains, some of the tested compounds showed good antimicrobial activity.     

Recovery of Immersions from Their Metric Tensors and Nonlinear Korn Inequalities: A Brief Survey

The authors discuss the existence and uniqueness up to isometries of Enof immersions φ : Ω  R~n→ E~n with prescribed metric tensor field(g ij) : Ω→ S~n, and discuss the continuity of the mapping(gij) →φ defined in this fashion with respect to various topologies. In particular, the case where the function spaces have little regularity is considered. How, in some cases, the continuity of the mapping(gij) →φ can be obtained by means of nonlinear Korn inequalities is shown.     

CR Geometry in 3-D

CR geometry studies the boundary of pseudo-convex manifolds.By concentrating on a choice of a contact form,the local geometry bears strong resemblence to conformal geometry.This paper deals with the role conformally invariant operators such as the Paneitz operator plays in the CR geometry in dimension three.While the sign of this operator is important in the embedding problem,the kernel of this operator is also closely connected with the stability of CR structures.The positivity of the CR-mass under the natural sign conditions of the Paneitz operator and the CR Yamabe operator is discussed.The CR positive mass theorem has a consequence for the existence of minimizer of the CR Yamabe problem.The pseudo-Einstein condition studied by Lee has a natural analogue in this dimension,and it is closely connected with the pluriharmonic functions.The author discusses the introduction of new conformally covariant operator P-prime and its associated Q-prime curvature and gives another natural way to find a canonical contact form among the class of pseudo-Einstein contact forms.Finally,an isoperimetric constant determined by the Q-prime curvature integral is discussed.     

平面应变状态下不可压缩幂硬化蠕变材料中刚性片状夹杂的奇异场和局部解

本文采用Williams特征展开方法结合Lee伪应力函数方法得到了平面应变状态下不可压缩幂硬化蠕变材料中刚性片状夹杂物的奇异场和局部解.研究发现,夹杂物尖端的应力奇性为r~(-m/2),与幂硬化指数m有关;而应变奇性为r~(-1/2),与幂硬化指数无关.本文通过选择积分路径给出了近尖的局部解,并用显函数的形式给出了近尖应力和位移的角变化.     

七十年代的传热学(续)

下面根据传热的机理将传热研究课题进行分类。当然,每种分类法都具有一定的任意性,并且有些是重复的。下面所提的各个项目都尽可能构成严格的研究课题。为便于查阅,大部分项目都注明应用分类的原编号(A,B,C,……)。这种按传热机理分类法可能给人们一种错觉,以为各种类型的传热方式都是独立存在的。事实上,在一个实际的传热问题里,往往有多种类型的传热过程同时存在。所以,希望读者不致在这方面产生误会。下面的排列次序先后并不表示课题的重要与否。     

A REVIEW OF POLAR STRATOSPHERIC CLOUD FORMATION

Liquid and solid particles in polar stratospheric clouds （PSCs） have been known to play a crucial role in the chemical loss of stratospheric ozone over the Antarctic and Arctic regions in late winter and early spring. The stratospheric aerosol and cloud particles provide the sites where fast heterogeneous chemical reactions convert inactive halogen reservoir species into potential ozone destroying radicals. The sedimentation of nitric acid-containing PSC particles irreversibly removes HNO3 gas （denitrification） from the lower stratosphere, which slows the return of chlorine to its inactive forms, resulting in more severe stratospheric ozone destruction. Although these clouds have been investigated extensively during the past decade using in situ field observation, laboratory experiment and modeling studies, the detailed microphysics processes under cold stratospheric conditions are still uncertain. This paper reviews the recent advances in our understanding of PSCs.     

FLOW STRUCTURE FORMATION AND EVOLUTION IN CIRCULATING GAS-FLUIDIZED BEDS

The occurrence of heterogeneous flow structures in gas-particle flows seriously affects the gas-solid contacting and transport processes in high-velocity gas-fluidized beds. Particles do not disperse uniformly in the flow but pass through the bed in a swarm of clusters. The so-called “core-annulus“ structure in the radial direction and “S“ shaped axial distribution of solids concentration characterize the typical flow structure in the system. A computational study, using the discrete particle approach based on molecular dynamics techniques, has been carried out to explore the mechanisms underlying formation of the clusters and the core-annulus structure. Based on energybudget analysis including work done by the drag force, kinetic energy, rotational energy, potential energy, and energy dissipation due to particle-particle and particle-wall collisions, the role of gas-solid interaction and inelastic collisions between the particles are elucidated. It is concluded that the competition between gas-solid interaction and particle-particle interaction determines the pattern formation in high-velocity gas-solid flows: if the gas-solid interaction (under elevated pressure) dominates, most of particle energy obtained by drag from the gas phase is partitioned such that particle potential energy is raised, leading to a uniform flow structure. Otherwise, a heterogeneous pattern exists, which could be induced by both particle -particle collisions and gas-solid interaction. Although both factors could cause the flow instability, the non-linear drag force is demonstrated to be the necessary condition to trigger heterogeneous flow structure formation. As gas velocity increases and goes beyond a critical value, the fluid-particle interaction suppresses particle collisional dissipation, and as a consequence a more homogeneous flow regime is formed.