bluuebunny/crossref_metadata_2025 huggingface dataset:
Tissue Specific Variation in Biochemical Compositions of Acorus calamus (L.) Leaves and Rhizomes
Authors: Ganjewala Deepak , Devi S Asha , Srivastava Ashwani Kumar
Published: May 2012

Sweet Flag (Acorus calamus L.) leaf and rhizome tissues were analyzed for biochemical compositions notably of carbohydrates and lipids. The glycolipid content measured in rhizome tissue was 62.3 mg%/FW almost double the glycolipid content (28.8 mg%/FW) in leaf tissues, whereas the sterol content in the leaf tissue (47.9 mg%/FW) was three times of the sterol content in rhizome tissues (15.5 mg%/FW). Carbohydrates content such as total sugar, reducing sugar, sucrose and fructose measured in leaf and rhizome tissues were more or less similar, with slightly higher values of total sugar (18.2 mg%/FW) in the leaf tissues. The study thus revealed variation in biochemical compositions in two different tissues leaf and rhizome of A. calamus.
Effects of Sampling Methods on Starch Granule Size Measurement of Potato Tubers under a Light Microscope
Authors: Li Xiu-Qing , Zhang Jichong , Luo Sainan , Liu Gongshe , Murphy Agnes , Leclerc Yves , Xing Ti
Published: May 2012

Measurement of starch granules by lightmicroscope is the preferred approach in most laboratories because it is simple, rapid and visual and because both size and shape can be investigated. However, juice from potato tubers consists of starch granules of very different sizes and precipitation/movement speeds which can cause artefacts when sampling the juice and recording microscopic images. In the previously described method, a razor blade was used to scrape and transfer juice from potato tubers directly to a drop of water on a slide for microscopic observation. In this study we used chambers made from tape on microscopic slides to reduce the cover-slip-induced shifting of small and medium granules. We improved the starch measurement reproducibility by testing various juice sampling methods. The reproducibility between repeated experiments using 10 cultivars was increased from a correlation coefficient r = 0.815 in the razor-blade-scraping method to r = 0.923 in a squeezing-juice method. The largest starch granule detected was 151 μm in length. Sampling methods (using a razor-blade or a garlic press) strongly influenced the granule length values measured from the same potato tuber. The results indicated that (1) The squeezing- juice approach is more reproducible, and (2) The average length of starch granules is one of the most reproducible scores but varies according to juice-sampling methods.
Occurrence, Distribution and Biological Variability of Zucchini Yellow Mosaic Virus in Cucurbits of Khuzestan Province, South West of Iran
Authors: Safara Somayeh , Hayati Jamshid , Roayaei Ardakani Mohammad , Kohi Habibi Mina
Published: May 2012

ZYMV is one of the most important plant viruses that cause economical damage in cucurbits. The symptoms of ZYMV in different cucurbits include stunting, yellowing, mottling, severe mosaic, leaf and fruit deformation, blistering and shoe string. Investigation on occurrence of this virus, in Khuzestan province was carried out in November 2009, April and May 2010 by collecting cucurbits samples from different cucurbits fields. After DAS-ELISA test, ZYMV was maintained in squash. Then total RNA were extracted and were tested by RT-PCR. Using RT-PCR, fragments belonging to N-terminal of coat protein and C-terminal of nuclear inclusion bodies were replicated. PCR product for investigation of replication was loaded in 1% agarose gel. From seven regions in Khuzestan, 175 leaf samples showing different symptoms (yellowing, mosaic, deformation and blistering) were collected. Seventy one samples out of total samples (175 samples) showed ZYMV infection. Occurrence of Zucchini Yellow Mosaic Virus in Khuzestan province was confirmed, using serological and RT-PCR tests. Infection of ZYMV in Khuzestan province (40.5%) is higher than the average of Iran’s infection (38%). This article is first report of occurrence ZYMV in different regions of Khuzestan province except Dezful.
Cholesteatoma After Lateral Bulla Osteotomy in Two Brachycephalic Dogs
Authors: Schuenemann Riccarda Martina , Oechtering Gerhard
Published: May 2012

This report describes a French bulldog and a pug that presented to the authors’ hospital following total ear canal ablation (TECA) and lateral bulla osteotomy (LBO), with signs of recurring otitis media and difficulty opening their mouths. The bulldog also had unilateral facial paralysis and sensory deficits of the trigeminal nerve on the ipsilateral side. Computed tomography and MRI scans suggested cholesteatoma in the bulldog, but showed only slight enlargement of the bulla in the pug. Histopathologic examination of samples yielded cholesteatoma in both cases. The authors suspect that development of the cholesteatomas was linked to the TECA/LBO surgery in both cases. Cholesteatomas may occur more frequently than currently thought. Even if only slight changes of the bulla wall are detected on CT, early-stage cholesteatoma should be considered. The narrow anatomic conditions in brachycephalic dogs possibly predispose such breeds to develop cholesteatoma after middle ear surgery because complete removal of all inflammatory and epithelial tissue can be more difficult than in other breeds. To the authors’ knowledge, this is the first report of an aural cholesteatoma causing sensory deficits of the trigeminal nerve.
Pharmaceutical Evaluation of Compounded Trilostane Products
Authors: Cook Audrey K. , Nieuwoudt Cornelia D. , Longhofer Susan L.
Published: May 2012

Compounded trilostane capsules (15 mg, 45 mg, or 100 mg) were purchased from eight pharmacies and assayed for content and dissolution characteristics. Capsules made in-house containing either inert material or 15 mg of the licensed product and proprietary capsules (30 mg and 60 mg) served as controls. Findings were compared with regulatory specifications for the licensed product. Altogether, 96 batches of compounded trilostane and 16 control batches underwent analysis. In total, 36 of 96 (38%) compounded batches were below the acceptance criteria for content. The average percentage label claim (% LC) for each batch ranged from 39% to 152.6% (mean, 97.0%). The range of average % LC for the controls was 96.1–99.6% (mean, 97.7%). The variance in content of the purchased compounded products was substantially greater than for the controls (234.65 versus 1.27; P<0.0001). All control batches exceeded the acceptance criteria for dissolution, but 19 of 96 batches (20%) of purchased compounded products did not. Mean percent dissolution for the purchased compounded products was lower than for controls (75.96% versus 85.12%; P=0.013). These findings indicate that trilostane content of compounded capsules may vary from the prescribed strength, and dissolution characteristics may not match those of the licensed product. The use of compounded trilostane products may therefore negatively impact the management of dogs with hyperadrenocorticism.
Diagnosis and Treatment of Tracheal Basal Cell Carcinoma in a Maine Coon and Long-Term Outcome
Authors: Green Michael L. , Smith Julie , Fineman Linda , Proulx David
Published: May 2012

A 6 yr old castrated male Maine coon presented with a 2 wk history of progressive dyspnea. Thoracic radiographs revealed a 2 cm diameter intratracheal mass at the level of the fourth rib. The tracheal mass was marginally excised via a combination of resection and anastomosis. Infiltrative basal cell carcinoma (BCC) with nodular osseous metaplasia was diagnosed. The thoracic trachea was then irradiated postoperatively for definitive treatment. The cat remained asymptomatic following surgical excision and radiation therapy for 32 mo when this report was written. The purpose of this report is to describe the treatment and long-term outcome of a Maine coon diagnosed with, and treated for, tracheal BCC.
Towards a Global Interdisciplinary Evidence-Informed Practice: Intimate Partner Violence in the Ethiopian Context
Authors: Guruge Sepali , Bender Amy , Aga Fekadu , Hyman Ilene , Tamiru Melesse , Hailemariam Damen , Kassa Andargachew , Refaie-Shirpak Khosro
Published: May 2012

Background. Intimate partner violence is a global health issue and is associated with a range of health problems for women. Nurses, as the largest health workforce globally, are well positioned to provide care for abused women. Objectives. This nursing-led interdisciplinary project was conducted to understand the current state of knowledge about intimate partner violence in Ethiopia and make recommendations for country-specific activities to improve response to intimate partner violence through practice changes, education, and research. Methods. The project involved two phases: review of relevant literature and an interdisciplinary stakeholder forum and a meeting with nurse educators. Findings. The literature review identified the pervasiveness and complexity of intimate partner violence and its sociocultural determinants in the Ethiopian context. Two significant themes emerged from the forum and the meeting: the value of bringing multiple disciplines together to address the complex issue of intimate partner violence and the need for health care professionals to better understand their roles and responsibilities in actively addressing intimate partner violence. Conclusions. Further research on the topic is needed, including studies of prevention and resilience and “best practices” for education and intervention. Interdisciplinary and international research networks can support local efforts to address and prevent intimate partner violence.
Use of Procalcitonin in Patients on Chronic Hemodialysis: Procalcitonin Is Not Related with Increased Serum Calcitonin
Authors: Mori Ken-Ichi , Noguchi Mitsuru , Sumino Yasuhiro , Sato Fuminori , Mimata Hiromitsu
Published: May 2012

Objectives. To investigate whether procalcitonin (PCT) could be useful for detecting bacterial infections in patients on hemodialysis (HD) and with increased calcitonin (CT). Methods. This prospective study included 42 males and 34 females on HD. The infection group consisted of 15 patients with proven bacterial infections; the other 61 patients were designated as the noninfection group. Serum C-reactive protein (CRP), interleukin (IL)-6, white blood cell (WBC) count, immature and total neutrophil (I/T) ratio, and CT were measured at the beginning of HD, and serum PCT levels at the beginning of HD and after HD. Results. The mean CT level in the both groups was apparently higher than that of nonchronic kidney disease. Significantly higher values between the infection and noninfection groups were seen for CRP, IL-6, WBC, I/T ratio, PCT, and CT. The PCT value of the area under the receiver operating characteristic curve was 0.921, which was significantly higher than the values for CRP (0.853; ), IL-6 (0.739; ), WBC (0.692; ), and I/T ratio (0.584; ). Conclusions. PCT was useful marker of bacterial infection in patients on HD and with increased CT. PCT levels should be determined before HD.
Vaginal Flatus and the Associated Risk Factors in Iranian Women: A Main Research Article
Authors: Veisi Firoozeh , Rezavand Negin , Zangeneh Maryam , Malekkhosravi Shohreh , Rezaei Mansour
Published: May 2012

Objective. The aim of the study was to determine the prevalence of vaginal flatus and some related risk factors in Iranian women. Methods. After conducting a pilot study, a sample size of 1000 subjects of 18 to 80 years was determined; of those 58 were unable to cooperate for various reasons. Age, parity, marital status, birth history, body mass index, and the weight of the largest newborn were collected. After a full gynecologic examination looking for pelvic organ prolapse, patients were asked about vaginal flatus and the frequency and time of occurrence. The results were studied using the chi-square test and independent t-test considering an alpha error of less than 0.05. Results. The prevalence of vaginal flatus was mainly 20% in this study, but embarrassment was observed in 5.7% of these women. 4% in the group were with no history of sexual contact (virgin). Vaginal flatus mostly started after vaginal delivery (45%) or spontaneously (34%); however, it was also reported after cesarean section and other pelvic operations. The most common activity leading to vaginal flatus was intercourse (54%); however, the time which had resulted in more inconvenience for the patients was during physical activities (92%). BMI and age were significantly lower in the patients (). The grade of prolapse was lower in the patients (). Conclusion. Low age, low body mass index, and vaginal delivery can affect the incidence of a noisy vagina.
Titrimetric and Spectrophotometric Assay of Ganciclovir in Pharmaceuticals Using Cerium(IV) Sulphate as the Oxidimetric Agent
Authors: Ramesh Pavagada J. , Basavaiah Kanakapura , Xavier Cijo M. , Prashanth Kudige N. , Raghu Madihalli S. , Vinay Kanakapura B.
Published: May 2012

Titrimetric and spectrophotometric assay of ganciclovir (GNC) is described using cerium(IV) sulphate as the oxidimetric reagent. The methods are based on the oxidation of GNC with a measured excess of cerium(IV) sulphate in acid medium followed by determination of the unreacted oxidant by two different reaction schemes. In titrimetry, the unreacted oxidant was determined by back titration with ferrous ammonium sulphate (FAS) in sulphuric acid medium, and spectrophotometry involves the reaction of residual cerium(IV) with p-DMAB to form brownish-coloured p-dimethylamino quinoneimine whose absorbance was measured at 460 nm. In both methods, the amount of cerium(IV) sulphate reacted corresponds to GNC concentration. Titrimetry is applicable over 3–10 mg range where as, in spcetrophotometry, the calibration graph is linear over the range of 2–10 μg mL−1 and the calculated molar absorptivity value is  L mol−1 cm−1. The validity of the proposed methods was tested by analyzing pure and dosage forms containing GNC. Statistical treatment of the results reflects that the proposed procedures are precise, accurate, and easily applicable for the determination of GNC pure form and in pharmaceutical formulations.
On the Order Statistics of Standard Normal-Based Power Method Distributions
Authors: Headrick Todd C. , Pant Mohan D.
Published: May 2012

This paper derives a procedure for determining the expectations of order statistics associated with the standard normal distribution () and its powers of order three and five ( and ). The procedure is demonstrated for sample sizes of . It is shown that and have expectations of order statistics that are functions of the expectations for and can be expressed in terms of explicit elementary functions for sample sizes of . For sample sizes of the expectations of the order statistics for , , and only require a single remainder term.
The Bi-Gamma ROC Curve in a Straightforward Manner
Authors: Ehtesham Hussain
Published: May 2012

In biomedical research, biomarkers (diagnostic tests) are used in distinguishing healthy and diseased populations. The effectiveness and accuracy of a biomarker generally assessed through the use of a Receiver Operating Characteristic (ROC) curve model, and its functional such as area under the curve (AUC). The parametric (smooth) ROC curves are obtained under the specific distributions assumptions. A resulting ROC curve model is the plot of sensitivity versus 1-specificity for all possible threshold values. Most popular and widely used ROC curve model is bi-normal ROC curve model under the assumptions of normality. When the biomarker results are continuous and positively skewed (non-normal). The gamma distribution is supposed to a flexible model for positively skewed measurements. In practice use of bi-gamma ROC curve model is hindered by the fact that ROC function cannot be written in closed-form. The solution of the problem is to use transformed invariance property of ROC curve model. Which assumes that the test results of both diseased and healthy are normally distributed after some monotone transformation [1]. In this paper we propose a simple approximation solution for the problem mentioned in above lines using a normal approximation due to Wilson and Hilfertys [2]. Which is useful to approximate gamma distribution results with classical normal distribution based results.
Sample Preparation For Metallography
Authors: Gokhale Atul B. , Banerjee Sharbari
Published: May 2012

Metallography is a highly evolved scientific field that plays a central role in materials characterization, research and development, process optimization, quality assurance, deformation studies, failure analysis, and reverse engineering. The primary means of metallographic sample preparation is mechanical in nature and consists of three distinct stages—sectioning, mounting, and grinding/polishing. However, products and procedures vary widely for different applications. This article describes how to make the most appropriate choices in performing sample preparation. A general discussion is followed by illustrative examples of four specific materials.
Kinematic Diffraction ofX‐Rays
Authors: Chen Haydn
Published: May 2012

Diffraction by x‐rays, electrons, or neutrons has enjoyed great success in crystal structure determination. For a perfectly ordered crystal, diffraction results in arrays of sharp Bragg reflection spots periodically arranged in reciprocal space. Analysis of the Bragg peak locations and their intensities leads to the identification of crystal lattice type, symmetry group, unit cell dimensions, and atomic configuration within a unit cell. On the other hand, for crystals containing lattice defects such as dislocations, precipitates, local ordered domains, surface, and interfaces, diffuse intensities are produced in addition to Bragg peaks. The distribution and magnitude of diffuse intensities are dependent on the type of imperfection present and the x‐ray energy used in a diffraction experiment.

Diffuse scattering is usually weak, and thus more difficult to measure, but it is rich in structure information that often cannot be obtained by other experimental means. Since real crystals are generally far from perfect, many properties exhibited by them are therefore determined by the lattice imperfections present. Consequently, understanding of the atomic structures of these lattice imperfections and of the roles these imperfections play is of paramount importance if these materials properties are to be exploited for optimal use.

This article addresses the fundamental principles of diffraction based upon the kinematic diffraction theory for x‐rays. Nevertheless, the diffraction principles described here may be extended to kinematic diffraction events involving thermal neutrons or electrons. In practice, most x‐ray diffraction experiments are carried out on crystals containing a sufficiently large number of defects that kinematic theory is generally applicable.

This article is divided into two major sections. In the first section, the fundamental principles of kinematic diffraction of x‐rays are discussed and a systematic treatment of theory is given. In the second section, the practical aspects of the method are discussed; specific expressions for kinematically diffracted x‐ray intensities are described and used to interpret diffraction behavior from real crystals containing lattice defects. Neither specific diffraction techniques and analysis nor sample preparation methods are described in this article.
Fracture Toughness Testing Methods
Authors: Landes John
Published: May 2012

Fracture mechanics is a technology that deals with the effects of a sharp crack on the load‐bearing capacity of materials and structures. It is a tool used to translate the results of laboratory fracture toughness testing into an analysis of structural safety and integrity of structural components. In this unit, the load–displacement behaviors of notched specimens are discussed and a brief description ofG,K,J, and δ is presented.
Deep Level Transient Spectroscopy
Authors: Tin Chin‐Che
Published: May 2012

Electrically active localized states, which give rise to defect levels, affect the electronic properties of semiconductor materials and devices. Defects can be beneficial or detrimental depending on their roles in controlling the dynamics of charge carriers in the materials. For instance, defects that give rise to deep levels help to produce semi‐insulating materials. Yet, defects have also been known to produce undesirable recombination centers detrimental to the performance of optoelectronic devices. The identification and control of defect levels are crucial in materials and electronic device development. Deep level transient spectroscopy (DLTS) is a powerful technique to characterize the defect structure of semiconductors. It has contributed much to the development of new materials and devices. Several variations of this technique have appeared since its invention, providing major improvements in both sensitivity and resolution as well as a wide range of applications. This technique can be used to characterize defects in both bulk and thin film materials, interface states of metal–insulator structures, as well as interfacial defects in devices such as field‐effect transistors and high electron mobility transistors. This paper introduces the concept underlying the DLTS technique by first describing the classical and conventional rate window method. Two major developments in data analysis using Fourier transform and Laplace transform are also presented to provide a view of the state‐of‐the‐art in DLTS.
Magnetic Moment and Magnetization
Authors: McHenry Michael E. , Laughlin David E.
Published: May 2012

This article explores theories describing magnetic dipole moments and magnetization, including the origin and coupling of magnetic dipole moments and their addition to yield a magnetization. In particular, we define field quantities and magnetic dipole moments. This is followed by discussion of the atomic origins of dipole moments, magnetization and dipolar interactions, and magnetization in superconductors. The coupling of magnetic dipole moments is discussed in the context of mean field and exchange theories. This allows for the definition of ferromagnetism, antiferromagnetism, and ferrimagnetism. The microscopic magnetization and domains are finally discussed.
Thermomagnetic Analysis
Authors: McHenry Michael E. , Lucas Matthew S.
Published: May 2012

This article reviews some techniques to measure magnetic ordering and to probe phase transitions and structural order in magnetic alloys. These impact on the classification and identification of magnetic phase transitions. The techniques include calorimetric probes of magnetic phase transitions, thermomagnetic measurements, and ancillary structural probes of magnetic order.
Magnetotransport in Metals and Alloys
Authors: Bass Jack
Published: May 2012

Electronic transport properties are fundamental to the classification of materials. The behaviors of the electrical resistivity ρ, the thermal conductivity κ, and the thermopowerSare used to define whether a material is a metal, a semiconductor, or an insulator. Studies of how ρ, κ, andSvary with impurity content (alloying), magnetic fieldB, sample size, deformation, and so on, provide insight into the nature of current carriers and how they are scattered. Studies of magnetoresistance, the variation of ρ withB, can yield additional information about electronic structure, the current carriers, and their scattering. In systems involving magnetic metals, ρ(B) has technical applications to magnetic sensing and memory. The Hall effect and the thermopowerScan often be used to infer the sign of the charge of the majority current carriers, and the thermal conductivity κ, while closely related to ρ, can manifest differences that contain significant information. The Hall effect in semiconductors also finds use in sensors, but in metals it is smaller and usually of more interest for the physical insight it can provide into both nonmagnetic and magnetic metals. Changes with magnetic field in the thermal conductivity and thermoelectric coefficients of metals are usually small and difficult to measure. They have provided useful information about physical phenomena such as many‐body contributions to thermoelectricity and giant magnetoresistance in granular alloys and magnetic multilayers but are much less studied than the resistivity and Hall effect. Transport and magnetotransport measurements of metals and alloys are made over a wide range of temperatures extending from the lowest achievable temperature to the liquid state.

This article focuses on four measured quantities in solid metals and alloys in the presence of a temporally constant and spatially uniform magnetic fieldB—the electrical resistanceR, the Hall resistanceRH, the thermal conductanceK, and the thermopowerS. The basic theory underlying these quantities applies also to liquid metals and alloys. The discussion begins with definitions and general information, including how to relate the measured quantities to the fundamental properties ρ, the Hall coefficientR0, κ, andS. These are followed by a brief description of the behaviors of ρ, κ, andSin zero magnetic field. Many more quantities than these four can be defined and measured, some of which have provided important information about metals. A few are briefly discussed.
Techniques for Corrosion Quantification
Authors: Frankel Gerald S.
Published: May 2012

Corrosion, the environmental degradation of materials, is a problem for many applications of materials, particularly for metals. Accurate evaluation of the susceptibility of a material to corrosion in a given environment and improvements made through, for instance, protective coatings or the addition of corrosion inhibitors to the environment are critical for successful utilization of materials in aggressive conditions. A number of techniques, both electrochemical and nonelectrochemical, have been developed to allow detailed characterization of the corrosion response and accurate prediction of component degradation. In this chapter several techniques are described, with an emphasis on electrochemical methods. These techniques use a fundamental understanding of corrosion kinetics as well as sensitive instrumentation to allow quick and informative assessments of corrosion rates. The Tafel technique using potentiodynamic polarization data also provides information about the rate‐limiting processes, the tendency toward passivity, and the likelihood for passivity breakdown by localized corrosion. However, it is not suitable for field monitoring. Linear polarization is simple, rapid, and very well suited for field monitoring of corrosion rates. The Tafel slopes must be known for accurate determination of corrosion rate, or they can be estimated with little resulting error. Electrochemical impedance spectroscopy is a powerful laboratory tool, particularly for resistive environments and coated metals. This chapter provides the principles, practical aspects, and problems associated with each technique. Some common nonelectrochemical methods are also discussed.
Ultraviolet Photoelectron Spectroscopy
Authors: Himpsel F. J.
Published: May 2012

A brief overview of ultraviolet photoelectron spectroscopy (UPS) and related techniques is given. This technique measures the occupied electronic states in solids and at surfaces. In its angle‐resolved version, it provides the complete information about electrons in solids. After discussing the underlying physics, a variety of applications in materials science are illustrated. Practical questions are addressed as well.
Ellipsometry
Authors: Arsov Lj. , Ramasubramanian M. , Popov B. N.
Published: May 2012

Ellipsometry, also known as reflection polarimetry or polarimetric spectroscopy, is a classical and precise method for determining the optical constants, thickness, and nature of reflecting surfaces or films formed on them. Ellipsometry derives its name from the measurement and tracking of elliptically polarized light that results from optical reflection. Typical experiments undertaken with this technique consist of measuring the changes in the state of polarization of light on reflection from the investigated surfaces. Hence, ellipsometry finds applicability in a wide variety of fields such as physical and chemical adsorption, corrosion, electrochemical and chemical formation of passive layers on metals, oxides, polymer films, semiconductor growth and microelectronics, biology, medicine, and immunological reactions. The main strength of this technique lies in its capability not only to allow
in situ
measurements and provide information about the growth kinetics of thin films but also simultaneously to allow the determination of many or all of the optical parameters necessary to quantify the system. Spectroscopic ellipsometry allows the accurate and swift characterization of optical constants and reflectivity for single and multilayer coatings with film thicknesses of from 0.1 nm to 30 μm. Phase‐modulated ellipsometry is more sophisticated and was developed in recent years thanks to the advent of computer control and multichannel detectors. Other configurations of ellipsometers for special purposes are tailored for qualification and online production control, photovoltaic applications and testing of solar cells, single or multiwavelength monitoring, and
in situ
film growth allowing the precise control of film deposition processes.
Impulsive Stimulated Thermal Scattering
Authors: Rogers John A. , Maznev Alex , Nelson Keith A.
Published: May 2012

Impulsive stimulated thermal scattering (ISTS) is a purely optical, noncontact method for characterizing the acoustic behavior of surfaces, thin membranes, coatings, and multilayer assemblies, as well as bulk materials. The method has emerged as a useful tool for materials research in part because (1) it enables accurate, fast, and nondestructive measurement of important acoustic (direct) and elastic (derived) properties that can be difficult or impossible to evaluate in thin films using other techniques; (2) it can be applied to a wide range of materials that occur in microelectronics, biotechnology, optics, and other areas of technology; and (3) it does not require specialized test structures or impedance‐matching fluids which are commonly needed for conventional mechanical and acoustic tests. Further, recent advances in experimental design have simplified the ISTS measurement dramatically, resulting in straightforward, low‐cost setups, and even in the development of a commercial ISTS photoacoustic instrument that requires no user adjustments of lasers or optics. With this tool, automated single‐point measurements, as well as scanning‐mode acquisition of images of acoustic and other physical properties, are routine.

ISTS, which is based on transient grating (TG) methods, is a spectroscopic technique that measures the acoustic properties of thin films over a range of acoustic wavelengths. This article focuses only on ISTS measurement of acoustic motions in thin films. It begins with an overview of other related measurement techniques. It then describes the ISTS acoustic data and demonstrates how it can be used to determine (1) the stress and flexural rigidity in thin membranes; (2) the elastic constants of membranes and supported films; and (3) the thicknesses of single or multiple films in multilayer stacks.
Electron Paramagnetic Resonance
Authors: Eaton Gareth R. , Eaton Sandra S.
Published: May 2012

Electron paramagnetic resonance (EPR), also known as electron spin resonance (ESR) or electron magnetic resonance (EMR), is the method of choice for characterizing unpaired electrons in materials. With proper attention to experimental methods, EPR can provide quantitation of the concentrations of unpaired electrons and characterize the chemical environment of the spin. It is routinely applied to solid or liquid samples. Cryogenic temperatures may be needed to observe transition metal ions with rapid electron spin relaxation.
Extrusion Foaming of a Preceramic Silicone Resin with a Variety of Profiles and Morphologies
Authors: Wolff Friedrich , Ceron Nicolat Bruno , Fey Tobias , Greil Peter , Münstedt Helmut
Published: May 2012

Preceramic foams with a variety of profiles and morphologies were fabricated by a continuous foam extrusion process based on a single‐screw extruder. A methyl silicone resin was used as the preceramic polymer and carbon dioxide as the foaming agent. Variations of the foam morphology were achieved by changing the key process parameters carbon dioxide content, foaming pressure, and foaming temperature. Samples of different porosities, cell densities, pore sizes, and pore size gradients were obtained. From these results, conditions for the fabrication of particular foam structures can be derived. Various foam profiles as rods, tapes, and tubes were extruded and pyrolysed into ceramic foams.
Plasticity Mechanisms in Sub‐Micron Al Fiber Investigated by In Situ TEM
Authors: Mompiou Frédéric , Legros Marc
Published: May 2012

Sub‐micron Al fibers have been tested mechanically in situ in a transmission electron microscope. Their plastic behavior appears to be strongly sensitive to their initial dislocation content. We report here observations on fibers that were obtained by a chemical etching of a eutectic alloy where isolated and stable sources operate. The strength of sources in fibers of different size has been directly measured. We show that the increase of the yield stress with decreasing fiber size can be directly attributed to the increase of the source strength.
Reversible Lithium Storage with High Mobility at Structural Defects in Amorphous Molybdenum Dioxide Electrode
Authors: Ku Jun H. , Ryu Ji Heon , Kim Sun Ha , Han Oc Hee , Oh Seung M.
Published: May 2012

This work demonstrates that structural defects in amorphous metal oxide electrodes can serve as a reversible Li+ storage site for lithium secondary batteries. For instance, molybdenum dioxide electrode in amorphous form (a‐MoO2) exhibits an unexpectedly high Li+ storage capacity (up to four Li per MoO2 unit), which is larger by a factor of four than that for the crystalline counterpart. The conversion‐type lithiation is discarded for this electrode from the absence of Mo metal and lithium oxide (Li2O) in the lithiated a‐MoO2 electrode and the retention of local structural framework. The sloping voltage profile in a wide potential range suggests that Li+ ions are inserted into the structural defects that are electrochemically nonequivalent. This electrode also shows an excellent cycle stability and rate capability. The latter feature is seemingly due to a rather opened Li+ diffusion pathway provided by the structural defects. A high Li+ mobility is confirmed from nuclear magnetic resonance study.
Nitroxide Radicals@US‐Tubes: New Spin Labels for Biomedical Applications
Authors: Rivera Eladio J. , Sethi Richa , Qu Feifei , Krishnamurthy Ramkumar , Muthupillai Raja , Alford Michael , Swanson Michael A. , Eaton Sandra S. , Eaton Gareth R. , Wilson Lon J.
Published: May 2012

The encapsulation of nitroxide radicals within ultrashort (ca. 50 nm) single‐walled carbon nanotubes (US‐tubes) is achieved. Tempo‐ and Iodo‐Tempo@US‐tubes are characterized by thermogravimetric analysis (TGA), X‐ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Electron paramagnetic resonance (EPR) spectra display characteristic signals due to the detection of the spin probes within the US‐tubes. Longitudinal proton relaxivities (r1) of both nitroxide@US‐tubes samples are 7 to 13 times greater than the free nitroxide radicals in solution, giving relaxivities comparable to the clinical contrast agent (CA) Magnevist. In addition, transverse proton relaxivities (r2) show unprecedented proton relaxation enhancement in comparison to any other reported nitroxide radical‐based system or the clinically approved T2 CA, Resovist, under the same conditions. T2‐weighted magnetic resonance imaging (MRI) phantom images show that the encapsulation of nitroxide radicals within the US‐tubes produces good contrast enhancement due to their high r2 relaxivities. The nitroxide radicals@US‐tube agents are a new promising class of spin probes for MRI and electronic paramagnetic resonance imaging (EPRI) labeling, tracking, and diagnosis.
Charge Density Dependent Nongeminate Recombination in Organic Bulk Heterojunction Solar Cells
Authors: Rauh Daniel , Deibel Carsten , Dyakonov Vladimir
Published: May 2012

Apparent recombination orders exceeding the value of two expected for bimolecular recombination have been reported for organic solar cells in various publications. Two prominent explanations are bimolecular losses with a carrier concentration dependent prefactor due to a trapping limited mobility and protection of trapped charge carriers from recombination by a donor–acceptor phase separation until re‐emission from these deep states. In order to clarify which mechanism is dominant temperature‐ and illumination‐dependent charge extraction measurements are performed under open circuit and short circuit conditions at poly(3‐hexylthiophene‐2,5‐diyl):[6,6]‐phenyl‐C61 butyric acid methyl ester (P3HT:PC61BM) and PTB7:PC71BM (poly[[4,8‐bis[(2‐ethylhexyl)oxy]benzo[1,2‐b:4,5‐b′]dithiophene‐2,6‐diyl][3‐fluoro‐2‐[(2‐ethylhexyl)carbonyl]thieno[3,4‐b]thiophenediyl]]) solar cells in combination with current–voltage characteristics. It is shown that the charge carrier density n dependence of the mobility μ and the recombination prefactor are different for P3HT:PC61BM at temperatures below 300 K and PTB7:PC71BM at room temperature. Therefore, in addition to μ(n), a detrapping limited recombination in systems with at least partial donor–acceptor phase separation is required to explain the high recombination orders.
Preparation of Highly Ordered Nitrogen‐Containing Mesoporous Carbon from a Gelatin Biomolecule and its Excellent Sensing of Acetic Acid
Authors: Mane Gurudas P. , Talapaneni Siddulu N. , Anand Chokkalingam , Varghese Shaji , Iwai Hideo , Ji Qingmin , Ariga Katsuhiko , Mori Toshiyuki , Vinu Ajayan
Published: May 2012

Novel nitrogen‐containing mesoporous carbon with well‐ordered pores (NMC‐G) and high basicity is synthesized using a low‐cost single‐molecule precursor, gelatin biomolecule, and SBA‐15 as a template via nanocasting method. The obtained materials are thoroughly characterized. It is found that the prepared materials have excellent textural properties such as high specific surface areas, huge pore volumes, and large pore diameters. The pore diameter of the materials can also be controlled with a simple adjustment of the pore diameter of the hard templates. The C/N ratio of the samples is calculated to be ≈6.01, which is slightly higher than that observed for mesoporous carbon nitride samples. X‐ray photoelectron spectroscopy (XPS) reveals the presence of sp2 hybridized carbon in aromatic ring structure attached to amino groups. The materials could adsorb a huge quantity of CO2. The sensing capability of the materials with different pore diameters for different adsorbates including ethanol, acetic acid, aniline, toluene, and ammonia is also investigated. Among the materials with different pore diameters studied, the material with the highest basicity and the largest pore diameter (NMC‐G‐150) showed excellent sensing performance with a high selectivity of adsorption for acetic acid molecule.
Nickel Silicide Nanowire Arrays for Anti‐Reflective Electrodes in Photovoltaics
Authors: Dasgupta Neil P. , Xu Shicheng , Jung Hee Joon , Iancu Andrei , Fasching Rainer , Sinclair Robert , Prinz Fritz B.
Published: May 2012

Conductive nanowires (NWs) provide several advantages as a template and electrode material for solar cells due to their favorable light scattering properties. While the majority of NW solar cell architectures studied are based on semiconductor materials, metallic NWs could provide equivalent anti‐reflection properties, while acting as a low‐resistance back contact for charge transport, and facilitate light scattering in thin layers of semiconductors coated on the surface. However, fabrication of single‐crystalline highly anti‐reflective NWs on low‐cost, flexible substrates remains a challenge to drive down the cost of NW solar cells. In this study, metallic NixSi NW arrays are fabricated by a simple, bottom‐up, and low‐cost method based on the thermal decomposition of silane on the surface of flexible Ni foil substrates without the need for lithography, etching or catalysts. The optical properties of these NW arrays demonstrate broadband suppression of reflection to levels below 1% from 350 nm to 1100 nm, which is among the highest values reported for NWs. A simple route to control the diameter and density of the NWs is introduced based on variations in a carrier gas flow rate. A high‐resolution TEM, XRD and TEM‐EDS study of the NWs reveals that they are single crystalline, with the phase and composition varying between Ni2Si and NiSi. The nanowire resistivity is measured to be 10−4 Ω‐cm, suggesting their use as an efficient back electrode material for nanostructured solar cells with favorable light scattering properties.
Graphene Oxide Gel‐Derived, Free‐Standing, Hierarchically Porous Carbon for High‐Capacity and High‐Rate Rechargeable Li‐O2 Batteries
Authors: Wang Zhong‐Li , Xu Dan , Xu Ji‐Jing , Zhang Lei‐Lei , Zhang Xin‐Bo
Published: May 2012

Lithium‐oxygen (Li‐O2) batteries are one of the most promising candidates for high‐energy‐density storage systems. However, the low utilization of porous carbon and the inefficient transport of reactants in the cathode limit terribly the practical capacity and, in particular, the rate capability of state‐of‐the‐art Li‐O2 batteries. Here, free‐standing, hierarchically porous carbon (FHPC) derived from graphene oxide (GO) gel in nickel foam without any additional binder is synthesized by a facile and effective in situ sol‐gel method, wherein the GO not only acts as a special carbon source, but also provides the framework of a 3D gel; more importantly, the proper acidity via its intrinsic COOH groups guarantees the formation of the whole structure. Interestingly, when employed as a cathode for Li‐O2 batteries, the capacity reaches 11 060 mA h g−1 at a current density of 0.2 mA cm−2 (280 mA g−1); and, unexpectedly, a high capacity of 2020 mA h g−1 can be obtained even the current density increases ten times, up to 2 mA cm−2 (2.8 A g−1), which is the best rate performance for Li‐O2 batteries reported to date. This excellent performance is attributed to the synergistic effect of the loose packing of the carbon, the hierarchical porous structure, and the high electronic conductivity of the Ni foam.
Re‐ordering Chaotic Carbon: Origins and Application of Textured Carbon
Authors: Shakerzadeh M. , Loh G. C. , Xu N. , Chow W. L. , Tan C. W. , Lu C. , Yap R. C. C. , Tan D. , Tsang S. H. , Teo E. H. T. , Tay B. K.
Published: May 2012

Formation of nanocrystals with preferred orientation within the amorphous carbon matrix has attracted lots of theoretical and experimental attentions recently. Interesting properties of this films, easy fabrication methods and practical problems associated with the growth of other carbon nanomaterials such as carbon nanotubes (CNTs) and graphene gives this new class of carbon nanostructure a potential to be considered as a replacement for some applications such as thermal management at nanoscale and interconnects. In this short review paper, the fabrication techniques and associated formation mechanisms of these nanostructured films have been discussed. Besides, electrical and thermal properties of these nanostructured films have been compared with CNTs and graphene.
The Current Move of Lithium Ion Batteries Towards the Next Phase
Authors: Kim Tae‐Hee , Park Jeong‐Seok , Chang Sung Kyun , Choi Seungdon , Ryu Ji Heon , Song Hyun‐Kon
Published: May 2012

Application targets of lithium ion batteries (LIBs) are moving from small‐sized mobile devices of information technology to large‐scale electric vehicles (xEVs) and energy storage systems (ESSs). Environmental issues and abruptly increasing power demands are pushing high performance energy storage devices or systems onto markets. LIBs are one of the most potential candidates as the energy storage devices mainly due to their high energy densities with fairly good rate capabilities and a fairly long cycle life. As battery systems become larger in terms of stored energy as well as physical size, the safety concerns should be more seriously cared. Each application target has its own specification so that electrode materials should be chosen to meet requirements of the corresponding application. This report diagnoses the current market trends of LIBs as a primary topic, followed by giving an overview of anode and cathode material candidates of LIBs for xEVs and ESSs based on their electrochemical properties.
A Highly Reversible Nano‐Si Anode Enabled by Mechanical Confinement in an Electrochemically Activated LixTi4Ni4Si7 Matrix
Authors: Son Seoung‐Bum , Kim Seul Cham , Kang Chan Soon , Yersak Thomas A. , Kim Yoon‐Chang , Lee Chun‐Gyoo , Moon Sung‐Hwan , Cho Jong Soo , Moon Jeong‐Tak , Oh Kyu Hwan , Lee Se‐Hee
Published: May 2012

This paper reports a Si‐Ti‐Ni ternary alloy developed for commercial application as an anode material for lithium ion batteries. Our alloy exhibits a stable capacity above 900 mAh g−1 after 50 cycles and a high coulombic efficiency of up to 99.7% during cycling. To enable a highly reversible nano‐Si anode, melt spinning is employed to embed nano‐Si particles in a Ti4Ni4Si7 matrix. The Ti4Ni4Si7 matrix fulfills two important purposes. First, it reduces the maximum stress evolved in the nano‐Si particles by applying a compressive stress to mechanically confine Si expansion during lithiation. And second, the Ti4Ni4Si7 matrix is a good mixed conductor that isolates nano‐Si from the liquid electrolyte, thus preventing parasitic reactions responsible for the formation of a solid electrolyte interphase. Given that a coulombic efficiency above 99.5% is rarely reported for Si based anode materials, this alloy's performance suggests a promising new approach to engineering Si anode materials.
Role of microwave heating strategies in enhancing the progress of a first‐order endothermic reaction
Authors: Bhattacharya Madhuchhanda , Venkata Sandeep KR , Basak Tanmay
Published: May 2012

A detailed analysis has been carried out by solving coupled energy and mass balance equations along with Helmholtz equation of microwave propagation to investigate the role of microwave heating strategies in enhancing the progress of a first‐order endothermic reaction in “thin,” “intermediate,” and “thick” regimes of microwave heating. It has been shown that heating strategy plays a critical role in maximizing the efficiency of microwave heated reactors, where progress of reactor can be greatly accelerated at a given input power by either configuring microwave sources at both sides of the reactor or preferentially focusing them on one side. A series of master curves have been provided showing percentage saving of reaction time in various configurations of microwave heated reactors compared to their conventional counterparts, which can be efficiently used to select appropriate heating strategy for different dimension and dielectric properties of the reacting medium. © 2012 American Institute of Chemical Engineers AIChE J, 59: 656–670, 2013
Effect of partial delignification of kenaf bast fibers for radiation graft copolymerization
Authors: Mohamed Nor Hasimah , Tamada Masao , Ueki Yuji , Seko Noriaki
Published: May 2012

Malaysian kenaf bast fiber was treated by acidic chlorite to be applied for a trunk polymer radiation‐induced graft copolymerization. The delignification conditions such as temperature, reaction time, and sodium chlorite (NaClO2) loading were optimized from the viewpoints of density, tensile strength, and reactivity of grafting. It was found that delignification condition at 80°C for 6 h with 0.5% NaClO2 gave 91% of lignin removal from the kenaf bast fibers. In this case, the density, fineness, and tensile strength of the kenaf fiber decreased about 46, 44, and 87%, respectively. Reactivity of grafting was evaluated using 4‐chloromethyl styrene to obtain widely available precursor materials. The partial delignified kenaf with residual lignin less than 2% resulted in degree of grafting of 134%, which is enough for precursor materials. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013