bluuebunny/crossref_metadata_2025 huggingface dataset:
Cerebellar Vermis Proteome of Chronic Alcoholic Individuals
Authors: Alexander‐Kaufman Kimberley , Harper Clive , Wilce Peter , Matsumoto Izuru
Published: June 2007

Background: Cerebellar changes are commonly associated with alcoholism and chronic alcohol consumption can produce profound impairments in motor functioning and various aspects of cognition. Although the mechanisms underlying alcohol‐induced changes in the cerebellar vermis are poorly understood, observations in the alcoholic vermis are thought to be consequential to common alcohol‐related factors, particularly thiamine deficiency.

Methods: In the present study, we used a proteomics‐based approach to compare protein expression profiles of the cerebellar vermis from human alcoholic individuals (both neurologically uncomplicated and alcoholic individuals complicated with liver cirrhosis) and healthy control brains. This article complements our recent studies performed on alcoholic prefrontal gray and white matter and splenium of the corpus callosum (CC).

Results: Like the CC study, several liver cirrhosis‐specific proteins were identified in the vermis, perhaps indicating the effects of liver dysfunction in this brain region. Among other protein expression changes observed are disturbances in the levels of thiamine‐dependent enzymes. A derangement in energy metabolism perhaps related to thiamine deficiency seems to be important in both alcoholic groups, even where there are no clinical or pathological findings of Wernicke–Korsakoff syndrome.

Conclusions: These results suggest that clinically and pathologically uncomplicated alcoholic cases may not in fact be “uncomplicated,” as at the proteome level we seem to be isolating the confounding effects of nutritional deficiencies and liver dysfunction and perhaps their role in alcohol‐related vermis damage. Together, these results indicate that the alcohol‐related pathology of the vermis is more multifactorial than other brain regions examined previously (prefrontal region and CC splenium).
Alcohol Consumption and Fatty Acid Intakes in the 2001–2002 National Health and Nutrition Examination Survey
Authors: Kim Soo Yeon , Breslow Rosalind A. , Ahn Jiyoung , Salem Norman
Published: June 2007

Background: Alcohol consumption has the potential to affect dietary intakes of nutrients; however, little is known about fatty acid intakes among alcohol consumers in the U.S. population.

Method: We examined the relation between self‐reported alcohol consumption and dietary fatty acid intake in 4,168 adults in the cross‐sectional National Health and Nutrition Examination Survey 2001–2002. Fatty acid intake was determined from a single, interviewer‐administered 24‐hour recall. The adjusted, weighted mean level of dietary fatty acid intakes, as characterized by nutrient density, was calculated as grams of fatty acid per 1,000 kcal of energy consumed according to average daily alcohol consumption and binge‐drinking episodes.

Results: Energy intake showed a significant increasing trend across alcohol consumption categories in both genders and binge‐drinking categories in men. Women binge drinkers also showed a higher energy intake compared with nonbinge drinkers. Among men, decreased nutrient densities of saturated, monounsaturated, polyunsaturated, linoleic, and α‐linolenic acids were associated with increasing alcohol consumption. Binge‐drinking men but not women had significantly decreased intakes of total saturates, monounsaturates, polyunsaturates and linoleic, α‐linolenic, eicosapentaenoic, and docosahexaenoic acid. When alcohol energy was excluded from calculation of nutrient densities, the results were similar to those with alcohol energy included, except that total saturated and monounsaturated fatty acid differences were no longer significant. In addition, there was an inverse relationship among men between binge‐drinking frequency and total polyunsaturates, linoleic, α‐linolenic, and eicosapentaenoic acids.

Conclusion: Our cross‐sectional results suggest that alcohol consumption may impact the dietary intake of essential fatty acids (EFAs). Given the public health importance of both alcohol consumption and intakes of EFAs, prospective studies of the relation should be considered.
Target‐Density Weighting Interpolation and Uncertainty Evaluation for Temporal Analysis of Census Data
Authors: Schroeder Jonathan P.
Published: June 2007

Conducting temporal analysis of census data often requires applying areal interpolation to integrate data that have been spatially aggregated using incompatible zoning systems. This article introduces a method of areal interpolation, target‐density weighting (TDW), that is useful for long‐term temporal analysis because it requires only readily available historical data and basic geographic information system operations. Then, through regression analysis of a large sample of U.S. census tract data, a model is produced that relates the error in TDW estimates of tract population to four basic properties of tracts. An analysis of model residuals combined with theorized absolute limits on interpolation error yields formulas with which we can compute upper and lower prediction bounds on the population in a tract of one census at the time of a different census. These prediction intervals enable the interpretation of different interpolated estimates with appropriately varying degrees of uncertainty.
Evaluation of Pulmonary Atresia with 64‐Slice Multidetector Computed Tomography (MDCT)
Authors: Faletra Francesco , Giardina Arianna , Petroni Renata , Carraro Chiara , Pasotti Elena , Pedrazzini Giovanni , Moccetti Tiziano
Published: June 2007

Pulmonary atresia with ventricular septal defect is a complex congenital heart disease. We report a case of a 46‐year‐old woman with pulmonary atresia and ventricular septal defect, surgically treated when she was 15 years old with an implant of a conduit between ascending aorta and left pulmonary branch. A 64‐slice computed tomography was performed to assess the conduit patency. The contrast enhanced MDCT study showed the conduit was pervious and correctly connected with an enlarged left pulmonary artery implant of a conduit between ascending aorta and left pulmonary branch.
Nurses' Conflicting Values in Competitively Managed Health Care
Authors: David Beverly Ann
Published: June 2007

The combined effect of the medical model of care and a philosophy of health care as a business is threatening the complex human interactions that are essential to nursing. In the United States, nursing in 1999 is practiced in an environment that restricts understanding of its value and purpose.
Clinical Commentary
Authors: Stevenson David K.
Published: June 2007

Catlin's article describes the results of a naturalistic inquiry into the opinions of physicians who resuscitate extremely low birth weight (ELBW) neonates. Factors such as role expectation, awareness, internal and external forces, burden, and continuing quandaries are discussed, but the theme of “uncertainty” seems to carry considerable weight in the author's conclusion that there is a need to “delineate ethical criteria for resuscitation.”
Ethical Decisions about Neonates in Norway
Authors: Brinchmann Berit Store
Published: June 2007

The aim of the study was to generate knowledge about ethical decision making by nurses and physicians in hospitals' neonatal units. The research question was; What ethical assessments underlie decisions about whether to start, continue, or stop medical treatment of very sick premature babies. The background was the investigator's interest in the relevance of different ethical positions in neonatal units. The theoretical framework was normative ethics; deontologic ethics, utilitarianism, Aristotelian virtue‐ethics theory, and an ethics of proximity (Vetlesen, 1994). This study describes knowledge about how ethical choices are made in practice, and will increase the empiric knowledge about ethical choices in neonatal units.

The study was descriptive. Empiric material was collected through field observations and interviews (Glaser & Strauss, 1967; Glaser 1978); 120 hours of field observations of physicians' and nurses' work with very sick premature babies were made during 10 months in 1995 and 1996 at one university hospital in northern Norway. In addition, 22 in‐depth interviews were conducted with 12 registered nurses and 4 physicians using a semi‐structured interview guide. Each interview was tape recorded and transcribed.
Generating and Testing Pain Management Standards Through Collaborative Research Utilization
Authors: Dufault Marlene A. , Sullivan Mary C.
Published: June 2007

Although major advances in research have given clinicians the tools to provide pain‐free hospitalization, inadequate pain relief continues to diminish patients' quality of care (Dufault, Bielecki, Collins, & Willey, 1995). Barriers to using current research for attaining best practice in pain management have been identified as providers' and patients' attitudes and lack of knowledge (Clarke et al., 1996), systems problems (Barnason, Merboth, Pozehl, & Tietjen, 1998), and regulatory obstacles (Yeager, Miaskowski, Dibble, & Wallhagan, 1997). Recently, inadequate pain management has expanded from an individual clinical problem to a public health policy issue as accreditation and regulatory groups have targeted pain management as an indicator of quality of care.
Adherence Between Molybdenum Sealing Foil and Vitreous Silica
Authors: Leichtfried Gerhard
Published: June 2007

The performance of vitreous silica seals is governed by the interaction between the molybdenum sealing foil and vitreous silica with respect to stress level and adherence. Mechanisms of sealing failures, i.e., oxidation from the outside and interface corrosion by the filling substance, are discussed with respect to affected lamps and requirements for the seal. With respect to wetting and chemical bonding, particular attention has to be directed toward the physical and chemical nature of second‐phase species in the interface, which is discussed for Y2O3 and TiO2. Using MY (Mo‐0.47wt% Y2O3–0.08wt% Ce2O3) foils, yttrium‐rich clusters with a size of a few nm up to 30 nm can be detected within the vitreous silica at a distance of up to 0.6 μm from the molybdenum/vitreous silica interface. In the MY sealing foil/vitreous silica interface, yttrium can be detected only locally, but always in combination with silicon. In the case of Mo‐0.55 wt% TiO2 foils, titanium can be found at each point measured within a distance of 0.58 μm from the interface for a vacuum‐collapse seal and 0.30 μm for a pinch seal. Titanium clusters with a size of 3–15 nm can be detected in the case of vacuum‐collapse‐sealed lamps, whereas in pinch‐sealed lamps, only a few clusters up to 5 μm occur very close to the interface.
Growth of Quasi‐Aligned AlN Nanofibers by Nitriding Combustion Synthesis
Authors: Radwan Mohamed , Miyamoto Yoshinari
Published: June 2007

Quasi‐aligned AlN nanofibers were formed by the nitriding combustion synthesis according to a unique micro‐reactor model. A charge composed of aluminum and aluminum nitride diluent powders (40/60 mol%) with a mixture of yttria and ammonium chloride as additives (5 wt% each) was combusted at low nitrogen gas pressures of 0.25 MPa. The FE‐SEM images of as‐synthesized AlN product showed the formation of ball‐like grains (same shape and size as the original Al reactant) that consisted of a thin surface nitride layer or crust cover quasi‐aligned AlN nanofibers grown in the interior. The cross‐sectional view is sea anemone like. Formation of this novel morphology is believed to occur through a two‐stage process. The first one occurs at the preliminary stage of the combustion outside Al particles. After the ignition, the heat generated causes the sublimation and dissociation of ammonium chloride into various gaseous species. This effectively interrupts the combustion and slows down the increase of reaction temperature. In addition, yttria interacts with the native oxide layer present on the surface of Al particles and forms a stable Al–N–Y–O crust. The second stage begins by the infiltration of various gaseous species such as HCl(g), NH3(g), and N2(g) through the crust into the molten Al cores. The “crust–core” systems function as “micro‐reactors” where both the nitridation and growth processes occur inside. The molten Al cores are spontaneously halogenated to AlCl3 vapors and the nitridation proceeds by the gas–gas reaction of AlCl3 and NH3/N2 vapors. The AlN nanofibers are then grown from the vapor phase quasi‐aligned inside the micro‐reactors by VLS and VS mechanisms.
Passport Examination by Polarized Infrared Spectra
Authors: Sugawara Shigeru
Published: June 2007

Abstract:  In this study, a new nondestructive technique for passport examination is proposed. In this technique, linearly polarized light is used to measure Fourier transform infrared (FT‐IR) reflectance spectra of films on the biographical data page. Thirty genuine and thirty‐five counterfeit Japanese passports and five marketed films pasted on name cards were examined. The measured spectra were analyzed as follows. The absorption spectra were obtained by the Kramers–Kronig transformations of reflectance spectra. The peak ratios were then calculated from the absorption spectra by adding the peak areas at 1126 and 1263 cm−1 and dividing the result by the peak area at 1727 cm−1. When nonpolarized light was used, the samples could not be distinguished by comparing the peak ratios. However, when polarized light was used, they were successfully distinguished by the comparison. Therefore, polarized light is useful for the forensic discrimination of passport films by the measurement of FT‐IR spectra.
The Use of a Tunable Light Source (Mini‐Crimescope MCS‐400, SPEX Forensics) in Dissecting Microscopic Detection of Cryptic Epithelial Particles
Authors: Schulz Martin M. , Wehner Frank , Wehner Heinz‐D.
Published: June 2007

Abstract: As skin particles are often deposited by even a single skin contact, the detection of skin debris is important for evidence collection and DNA testing. Unfortunately, even when a dissecting microscope is used by an experienced examiner, epidermal particles are often hard to find and these traces of evidence might escape DNA analysis. Fluorescence is defined as the property of absorbing short‐wavelength light and emitting longer‐wavelength light. By virtue of the fluorescence characteristics of many target materials, tunable light sources assist in the macroscopic search of crime scenes and items. We combined the dissecting microscope and an alternate light source to examine the fluorescence characteristics of skin and skin particles. In a comparative study, small skin scales were hidden between sand, fibers, and soil probes, and it proved possible to search more successfully with less time and effort. On staged casework exhibits, the efficiency of the screening aid was again tested and the usability of the new procedure shown.
Development of a Quantitative LC‐MS/MS Method for the Analysis of Common Propellant Powder Stabilizers in Gunshot Residue*
Authors: Laza Désiré , Nys Bart , Kinder Jan De , Kirsch‐De Mesmaeker Andrée , Moucheron Cécile
Published: June 2007

Abstract: In traditional scanning electron microscopy/energy dispersive X‐ray analysis of gunshot residue (GSR), one has to cope more and more frequently with limitations of this technique due to the use of lead‐free ammunition or ammunition lacking heavy metals. New methods for the analysis of the organic components of common propellant powder stabilizers were developed based on liquid chromatography coupled to tandem mass spectrometry (LC‐MS/MS). A multiple reactions monitoring scanning method was created for the screening of akardite II, ethylcentralite, diphenylamine, methylcentralite, N‐nitrosodiphenylamine, 2‐nitrodiphenylamine, and 4‐nitrodiphenylamine, present in standards mixtures. Five out of seven of these target compounds can be selectively identified and distinguished from the two others with a high accuracy. Samples from the hands of a shooter were collected by swabbing and underwent solid phase extraction prior to analysis. Detection limits ranging from 5 to 115 μg injected were achieved. Results from several firing trials show that the LC‐MS/MS method is suitable for the detection of stabilizers in samples collected following the firing of 9 mm Para ammunitions.
Chinese Population Data in Luoyang at Two Short Tandem Repeat Loci
Authors: Xu Jiejie , Zhang Weijuan
Published: June 2007

Population:  Chinese population in Luoyang (N = 116).
Genetic Diversity of Five STR Loci in Southeastern China
Authors: Wei Yonggang , Liu Tingting , Li Jingdong , Zhang Lin , Ying Binwu , Li Bo
Published: June 2007

Population:  Chinese
Complex Autoerotic Death with Full Body Wrapping in a Plastic Body Bag
Authors: Schellenberg Morgan , Racette Stéphanie , Sauvageau Anny
Published: June 2007

Abstract:  Autoerotic deaths are normally classified as accidental deaths occurring during individual, and usually solitary, sexual activity in which a device, apparatus, or prop used to enhance sexual stimulation of the deceased somehow causes unintended death. The most common methods of autoerotic practices are asphyxia by hanging, ligature, plastic bag, chemical substances, or a mixture of these. However, atypical methods such as overdressing/body wrapping have also been reported. In fact, overdressing/body wrapping is so rare that it is implicated in only 1.5% of published cases. Although plastic bags are often implicated in autoerotic deaths, there has been only one previous case that involved a plastic covering the victim’s body from head to toe. We here report the case of a 34‐year‐old man who died due to asphyxia, secondary to body wrapping in the largest and most complex plastic bag ever involved in a published case of autoerotic death.
Population Genetics of Two STR Loci D2S1322 and D2S1356 in a Chinese Han Population in Hohhot
Authors: Cai Ji Feng , Lan Ling Mei , Sun Xiao Ming , Wang Zhen Xia , Liang Wei Bo , Chang Yun Feng , Deng Ren Li
Published: June 2007

Population:  Chinese
Negative evidence of parthenogenesis induction byWolbachiain a gallwasp species,Dryocosmus kuriphilus
Authors: Zhu Dao‐Hong , He Yi‐Yuan , Fan Yong‐Sheng , Ma Ming‐Yong , Peng De‐Liang
Published: June 2007

The alpha‐proteobacteria of the genusWolbachiais a widespread group of maternally inherited endosymbionts of arthropod and nematode hosts.Wolbachiainfection induces a range of host phenotypes, including cytoplasmic incompatibility, male killing, feminization, and induction of thelytokous parthenogenesis. Heterogony (cyclical parthenogenesis) is a remarkable characteristic of oak gallwasps, Cynipini, the largest tribe of the Cynipidae. A few species of Cynipini are exceptional in that they are univoltine and exhibit thelytokous parthenogenesis, probably because they lost the arrhenotokous generation of their heterogonic ancestor species due toWolbachiainfection. In this study, the presence ofWolbachiawas detected using polymerase chain reaction primers for thewspgenes in a thelytokous parthenogenetic species [Dryocosmus kuriphilus(Yasumatsu)] (Hymenoptera: Cynipidae: Cynipini). Approximately 29.8 and 87.1% of adults of the Zhuzhou and Fuzhou strains, respectively, were infected withWolbachiawhile all females of the remaining four strains collected from other localities in China wereWolbachiafree. The length of thewspfragment of Zhuzhou and Fuzhou strains was found to be 573 and 561 bp, respectively. The nucleotide sequence of the bacterialwspfragment indicated that the endosymbiotic bacteria of the Zhuzhou and Fuzhou strains are members of supergroup A, but belong to different clades; they probably originated from two independent infection events. In conclusion, thelytokous parthenogenesis ofD. kuriphilusis not caused byWolbachiainfection and the deletion of the arrhenotokous generation is thus not associated with such an infection.
The Relationship Between Adolescent and Young Fathers’ Capital and Marital Plans of Couples Expecting a Baby*
Authors: Fagan Jay , Schmitz Mark F. , Lloyd Jacqueline J.
Published: June 2007

Abstract:We examined the relationship between fathers’ human, social, and financial capital and future marital plans among 176 pregnant adolescent mothers and the fathers of their babies. Fathers’ social capital proved to be the most significant resource in relation to marital plans. Mothers and fathers were significantly more likely to plan to marry when the father was involved in the pregnancy and when there was less couple conflict. Couples were more likely to agree about marriage when the mother and father agree that the father was involved in these aspects of parenting and when the couple agrees about high level of parenting alliance. Healthy Marriage initiatives should target young fathers’ social capital as well as plans for marriage.
Factors Associated With Involvement in Marriage Preparation Programs
Authors: Duncan Stephen F. , Holman Thomas B. , Yang Chongming
Published: June 2007

Abstract: Little is known empirically about the characteristics of couples who do and do not participate in marriage preparation. This study assessed the individual, couple, family, and sociocultural context variables that distinguish couples who become involved in marriage preparation from those who do not, using a sample of 7,331 couples. The results showed that the individual characteristics of valuing marriage, being kind and considerate, and being mature, and the couple context factor of perceived relationship problems, predicted involvement. Implications for increasing attendance in marriage preparation interventions include maximizing efforts to reach the “likely‐to‐attend group,” as identified in our findings. With this base of support for the value of interventions, we can then look to the less‐likely‐to‐attend group, who will take more resources of time, energy, and money to get to attend.
Self‐Directed, Therapist‐Directed, and Assessment‐Based Interventions for Premarital Couples*
Authors: Busby Dean M. , Ivey David C. , Harris Steven M. , Ates Chance
Published: June 2007

Abstract: In this study, we present the findings of an investigation of the effectiveness of 3 models of premarital education. The study compares the outcomes between a workbook‐only self‐directed program, a therapist‐directed (unstructured) program, and an assessment‐based (RELATE) relationship enhancement program. Results revealed significant differences in effectiveness between the 3 approaches at the 6‐month follow‐up. The assessment‐based program had more influence than the therapist‐directed and self‐directed programs on problem areas and was better than the therapist‐directed program at improving communication and relationship satisfaction. Participants indicated that the most helpful aspects of these programs were the opportunity to discuss previously undiscussed issues, improvements in communication, and the perspectives provided by the facilitator.
CREB and cAMP response element‐mediated gene expression in the ischemic brain
Authors: Kitagawa Kazuo
Published: June 2007

Cerebral ischemia triggers robust phosphorylation of cAMP response element‐binding protein (CREB) and CRE‐mediated gene expression in neurons. Glutamate receptor activation and subsequent calcium influx may activate CREB shortly after ischemia. CREB activation leads to expression of genes encoding neuroprotective molecules, such as the antiapoptotic protein Bcl‐2, and contributes to survival of neurons after ischemic insult. Recent studies have suggested that CREB may be involved in acquisition of ischemic tolerance, a phenomenon that occurs after sublethal ischemic stress. CREB activation is also involved in the survival of newborn neurons in the dentate gyrus of the hippocampus after ischemia. Therefore, CREB‐related therapeutics may be promising for brain protection and endogenous neurogenesis and could promote functional recovery in ischemic stroke patients. This minireview summarizes our current understanding for the role of CREB in regulating CRE‐mediated gene expression during cerebral ischemia.
Child Care Health Consultation: An Ecological Model
Authors: Crowley Angela A.
Published: June 2007

ISSUES AND PURPOSE.To present an ecological model of child care health consultation that defines the role of the health consultant as a resource and advocate within child care programs, as well as a supportive link among families, child care providers, and the healthcare system.

CONCLUSIONS.Nurses have provided health consultation to child care programs for more than 30 years and represent the majority of health consultants nationally. Pediatric nurses and advanced practice nurses are well prepared to shape and lead the development of this emerging role.

PRACTICE IMPLICATIONS.With expertise in caring for children, understanding families, and care across systems, pediatric nurses and advanced practice nurses should engage in current state and national efforts to develop child care health consultatits.
The Use of Dexamethasone in the Prevention of Postextubation Stridor in Pediatric Patients in PICU/NICU Settings: An Analytical Review
Authors: Jansaithong Jarassri
Published: June 2007

ISSUES AND PURPOSE. Dexamethasone has been used to prevent postextubation stridor in children, but its use is controversial. Five randomized, controlled clinical trials were reviewed to analyze the effectiveness of prophylactic dexamethasone on postextubation stridor in pediatric patients.

CONCLUSIONS. Previous studies had inconsistent results. Several factors may contribute to postextubation stridor in pediatric patients. Postextubation stridor and extubation failure do not always result from airway edema.

PRACTICE IMPLICATIONS. In addition to prophylactic dexamethasone, other approaches should be used to prevent postextubation stridor, such as preparing the patient, following established guidelines, and providing appropriate postextubation care.
Taking a Temperature: Which Way Is Best?
Authors: Kiernan Barbara S.
Published: June 2007

Ask the Expert provides research‐based answers to practice questions submitted by JSPN readers.
News From the Society
Authors: Nicholson Dana
Published: June 2007

News From the Society showcases SPN activities of interest to JSPN readers.
Liability and Just Cause
Authors: Hurka Thomas
Published: June 2007

This paper is a response to Jeff McMahan‘s “Just Cause for War” (Ethics & International Affairs 19, 2005). McMahan holds, as many have, that there is a just cause for war against group X only if X have made themselves liable to military force by being responsible for some serious wrong. But he interprets this liability requirement in a very strict way. He insists (1) that one may use force against X for purpose Y only if they are responsible for a wrong specifically connected to Y; and (2) that one may use force against an individual member of X only if he himself shares in the responsibility for the wrong. This paper defends a more permissive, and more traditional, view of just war liability against McMahan's claims. Against McMahan‘s first claim it argues that certain “conditional just causes,” such as disarming an aggressor, deterring future aggression, and preventing lesser humanitarian crimes, can be legitimate goals of war against X even if X have no specific liability connected to them. Against McMahan's second claim it argues that soldiers who have no responsibility for X‘s wrong may nonetheless be legitimately attacked because in becoming soldiers they freely surrendered their right not to be killed by enemy combatants in a war between their and another state, so killing them in such a war is not unjust. Though initially a criticism of McMahan, the paper makes positive proposals about conditional just causes and the moral justification for directing force at soldiers.
Crime and Punishment: Holding States Accountable
Authors: Lang Anthony F.
Published: June 2007

Should states be held responsible and punished for violations of international law? The recent ruling by the International Court of Justice that Serbia cannot be held responsible for genocide in Bosnia reflects the predominant international legal position. But such a position leaves open the possibility that states or nonstate agents can never be held responsible for international crimes. This article argues that they can and should be. While most international ethicists and legal theorists reject the punishment of corporate entities such as states, this article argues that certain types of international violations can only be undertaken by states, and, as a result, states must bear the responsibility for them. Drawing on some neglected strands in international law and political theory, the article sketches a potential institutional framework for the punishment of state crimes, particularly genocide and aggression.
Activation of Ca2+‐dependent protein kinase II during repeated contractions in single muscle fibres from mouse is dependent on the frequency of sarcoplasmic reticulum Ca2+ release
Authors: Aydin J. , Korhonen T. , Tavi P. , Allen D. G. , Westerblad H. , Bruton J. D.
Published: June 2007

Aim:  To investigate the importance and contribution of calmodulin‐dependent protein kinase II (CaMKII) activity on sarcoplasmic reticulum (SR) Ca2+‐release in response to different work intensities in single, intact muscle fibres.

Methods:  CaMKII activity was blocked in single muscle fibres using either the inhibitory peptide AC3‐I or the pharmacological inhibitor KN‐93. The effect on tetanic force production and [Ca2+]i was determined during work of different intensities. The activity of CaMKII was assessed by mathematical modelling.

Results:  Using a standard protocol to induce fatigue (50× 70 Hz, 350 ms duration, every 2 s) the number of stimuli needed to induce fatigue was decreased from 47 ± 3 contractions in control to 33 ± 3 with AC3‐I. KN‐93 was a more potent inhibitor, decreasing the number of contractions needed to induce fatigue to 15 ± 3. Tetanic [Ca2+]i was 100 ± 11%, 97 ± 11% and 67 ± 11% at the end of stimulation in control, AC3‐I and KN‐93 respectively. A similar inhibition was obtained using a high intensity protocol (20× 70 Hz, 200 ms duration, every 300 ms). However, using a long interval protocol (25× 70 Hz, 350 ms duration, every 5 s) no change was observed in either tetanic [Ca2+]i or force when inhibiting CaMKII. A mathematical model used to investigate the activation pattern of CaMKII suggests that there is a threshold of active CaMKII that has to be surpassed in order for CaMKII to affect SR Ca2+ release.

Conclusion:  Our results show that CaMKII is crucial for maintaining proper SR Ca2+ release and that this is regulated in a work intensity manner.
D
X
-like centers in InAs∕GaAs QDIPs observed by polarization-dependent Fourier transform infrared spectroscopy
Authors: Zhao Z. Y. , Yi C. , Stiff-Roberts A. D. , Hoffman A. J. , Wasserman D. , Gmachl C.
Published: June 2007

In order to decrease dark current density and improve spectral response tunability of quantum dot infrared photodetectors (QDIPs), it is critical to understand how dopants are incorporated into quantum dot active regions. In this article, polarization-dependent Fourier transform infrared absorbance spectroscopy is used to measure intraband absorption in InAs∕GaAs QDIP heterostructures featuring different molecular beam epitaxy remote doping schemes. In addition to a QD absorbance peak near 90meV, a peak at 405meV is observed. This peak at 405meV demonstrates signature characteristics of DX centers in III-V semiconductors, such as spherical symmetry, thermal activation of trapped carriers with increasing temperature, and dependence of absorbance peak magnitude (and thereby DX center concentration) on doping concentration and doping scheme. A conduction band energy diagram for the observed DX-like center and the corresponding optical ionization process is proposed. In addition, the effect of these DX-like centers on measured dark current density at T=50K of the corresponding fabricated QDIPs is discussed.
Promising new valved source for Ga or In evaporation
Authors: Sacks R. N. , Bichrt Craig
Published: June 2007

A new valved source for evaporation of Ga or In has been demonstrated. Its performance in terms of controlling the group III flux has been shown to be very good to excellent in terms of response time (2–3s), reproducibility (∼1%), stability (∼0.1%), and shut-off ratio (at least 30:1). In addition, this cell has produced GaAs, InGaAs, and InAlAs layers with material quality comparable to other state-of-the-art sources in terms of uniformity, surface morphology, background doping, carrier mobility, and p-i-n device performance. Finally, it has been demonstrated that the graphite-based material used for the crucible and valve in this source does not generate any extra carbon doping compared to the usual pyrolytic boron nitride-based crucibles.
rf oxygen plasma assisted molecular beam epitaxy growth of BiFeO3 thin films on SrTiO3 (001)
Authors: Kabelac J. , Ghosh S. , Dobal P. , Katiyar R.
Published: June 2007

Bi Fe O 3 (BFO) thin films were grown epitaxially by rf oxygen plasma assisted molecular beam epitaxy on SrTiO3 (001) substrates with and without SrRuO3 (SRO) thin film electrodes. BFO thin films show excellent crystalline quality and x-ray diffraction studies show the presence of only one phase. Polarized Raman spectroscopy also confirmed high crystalline quality of the films. BFO thin films show presence of ferroelectricity on conducting Nb:STO substrates and SRO-STO. Films on Nb:STO have leakage currents ∼0.1μA∕cm2 and remnant polarization ∼28μC∕cm2. Films on SRO-STO have leakage currents ∼8nA∕cm2 and remnant polarization ∼56μC∕cm2. Nb diffusion and poor surface quality of Nb:STO can be attributed to the difference in ferroelectric and leakage properties of the BFO thin films grown on Nb:STO and SRO-STO.
Thermodynamic analysis of cation incorporation during molecular beam epitaxy of nitride films using metal-rich growth conditions
Authors: Hoke W. E. , Torabi A. , Mosca J. J. , Kennedy T. D.
Published: June 2007

The conventional approach to growth of the nitride films GaN, AlN, InN, and their alloys by rf plasma molecular beam epitaxy uses metal-rich surface conditions due to improved material quality compared to nitrogen-rich conditions. The surface metal may incorporate into the growing film, act as a surfactant, and/or react with the underlying film or substrate. Using a simple chemical exchange reaction model and tabulated thermodynamic data at molecular beam epitaxy growth temperatures the predicted preferential incorporation series on the column III site under metal-rich conditions is found to be Al>B,Be,Si, Mg>Ga>In,Fe. This series is consistent with the observed ternary growth behavior and surfactant order. The series is also consistent with silicon migration in AlN but not GaN, sharper beryllium transitions in GaN than AlN, the significant migration of iron in GaN, and the reactivity of AlN nucleation layers with SiC surfaces. The model is used to predict boron incorporation under metal-rich conditions in BGaN and BAlN and should prove useful as a tool in predicting the incorporation behavior of other cations during metal-rich epitaxial growth of nitride films and possibly other materials.
Unintentional calcium incorporation in Ga(Al, In, N)As
Authors: Hurst J. B. , Lewis Shannon D. , Oye Michael M. , Holmes Archie L. , Ptak A. J. , Reedy R. C.
Published: June 2007

Unintentional calcium incorporation into GaInNAs causes an acceptor-type impurity, which limits the ability of ∼1eV GaInNAs-based solar cells to collect photogenerated current. Here, the authors focus on better understanding the conditions by which Ca is incorporated into GaInNAs. Various material combinations were grown including GaAs, InGaAs, GaInNAs, and Al(Ga)As. The materials were primarily grown by solid-source molecular-beam epitaxy (MBE) at ∼400 and 580–620°C, with comparisons made to metal-organic chemical vapor deposition (MOCVD)-grown materials where appropriate. Calcium incorporation was measured through secondary ion mass spectrometry. There was no measurable Ca incorporation into MBE-grown GaAs at 580°C, but Ca incorporates into GaAs at low MBE growth temperatures (∼400°C) that are comparable to those typically used for GaInNAs. This suggests that the N species is not solely responsible for the observed Ca incorporation into MBE-grown GaInNAs; but rather, defects associated with the low temperature growth may also be a factor. The effects of defect-related Ca incorporation were further studied at interfaces between Al(Ga)As and GaAs, and substrates pretreated with an O2 plasma and NH4OH etch. Ca incorporation was observed at the interface between Al0.3Ga0.7As∕GaAs, AlAs∕GaAs, and at the epilayer/substrate interface for the pretreated samples. No Ca was observed in InGaAs samples grown by either MBE or MOCVD, suggesting the Ca incorporation into GaInNAs has something to do with the addition of nitrogen. Therefore, the authors propose that the likely causes of Ca incorporation into GaInNAs are a Ca–N affinity, defects generated by low temperature growth, defects generated by the incorporation of N into GaAs, or some combination thereof.
Impact of arsenic species (As2∕As4) on the relaxation and morphology of step-graded InAsxP1−x on InP substrates
Authors: Zhang Wanming , Yi Changhyun , Brown April
Published: June 2007

The influence of arsenic species (As2 or As4) on compositionally graded InAsxP1−x buffer layers (x=0.15–0.8) grown by molecular beam epitaxy on InP is investigated. It was found that As2 has a higher incorporation rate than As4. Anisotropic strain relaxation occurs for samples grown with As4, with higher relaxation along [110] and lower relaxation along [1–10]. Relatively high and isotropic strain relaxation occurs for buffers grown with As2. The observed mosaic broadening is much greater when using As2. Atomic force microscopy morphological features are consistent with the strain relaxation results. Strong corrugations along [1–10] dominate the surface of films grown with As4, while grainy surfaces occur with As2. The use of As4 increased the overall surface roughness. The authors interpret these results with a simple model: the higher incorporation rate of As2 enables In to incorporate more uniformly in the two perpendicular ⟨110⟩ directions, while the lower incorporation rate of As4 decreases this uniformity. The different incorporation rates of In in the [110] and [1–10] directions may result in diverse morphologies and strain relaxation induced by arsenic spices.
High quality of 830nm material grown by solid source molecular beam epitaxy for laser device printing applications
Authors: Hernandez I. C. , McElhinney M. , Zeng L. , Mishournyi V. A.
Published: June 2007

Molecular beam epitaxy (MBE) has been employed almost entirely for the growth of arsenic compounds due to the lack of a suitable suitable solid phosphorous source. Advanced phosphide epitaxy has only been performed by metal organic chemical vapor deposition and phosphide based gas-source MBE. Solid source MBE (SSMBE), however, is capable of growing GaInAsP and AlGaInP layer structures without using toxic gases as source material. The key of SSMBE in producing high quality phosphides is a valved cracker cell for elemental phosphorus and arsenic, as well as the optimization of growth conditions such as growth temperature, P cracking zone temperature, P∕As ratio, ΔT between inner and outer heaters, and doping profiles. The 830nm material was grown in GEN III reactor on 2in. GaAs wafers doped with Si. Substrate growth temperature by a pyrometer was 500°C, the cracker temperature was kept at 850°C, and ΔT at 12°C. To verify the material quality, wafers were processed to make lasers with different cavity lengths and 56μm emitter widths. Internal quantum efficiency (ηi) of 95.5% and internal optical losses (αi) of 0.47cm−1 at 25°C were obtained. Devices were burn in for more than 5000h at cw mode, indicating high reliability.
Manufacturing method for the fabrication of sub-50nm current-perpendicular-to-plane spin valve sensors
Authors: Han G. C. , Li K. B. , Zheng Y. K. , Qiu J. J. , Luo P. , An L. H. , Guo Z. B. , Liu Z. Y. , Wu Y. H.
Published: June 2007

A manufacturing method is developed for the fabrication of sub-50nm current-perpendicular-to-plane (CPP) spin valve sensors. A feature size reduction process is used to reduce the feature size from above 100nm, which is determined by lithography process, to sub-50nm. The approach is to use the isotropic wet etch of a hard mask to reduce its transverse dimension and transfer the reduced dimension to CPP sensors by a subsequent etch process. In this approach, the sensor size is controlled by the wet etch, which can, in principle, be reduced to several nanometers. For CPP sensor fabrication, resist flattening and etch back processes are developed to avoid the alignment issues for the opening of sensor contacts. Using this approach, CPP sensors with sub-50nm track width have been fabricated. Magnetoresistance measurement shows that the sensor has a reasonable performance.
Fabrication of local microvacuum package incorporating Si field emitter array and Ti getter
Authors: Noda Daiji , Hatakeyama Masanori , Nishijyou Kichinosuke , Sawada Kazuaki , Ishida Makoto
Published: June 2007

Field emitters have high-speed response characteristics at over 100GHz because they utilize electron emission in a vacuum. Therefore, field emission devices are very suitable for use as high-speed switching elements. Practical field emitters can be fabricated by using the Si process. Consequently, the authors have fabricated a local vacuum package on a Si substrate that is adapted to the integrated circuit process for on-chip integrated devices. The technique was then used to fabricate Si field emitter arrays with integrated circuits on Si substrates. This has the great advantage that devices can be aligned on a micrometer size. This technique is very useful for many applications involving high performance on-chip integrated devices.
Anomalous x-ray diffraction study of disorders in epitaxial films of the Heusler alloy Co2MnGe
Authors: Collins Brian A. , Zhong Yuncheng , Chu Yong S. , He Liang , Tsui Frank
Published: June 2007

The authors report a study of structural and chemical disorders in a ternary combinatorial epitaxial film of CoxMnyGe1−x−y in the composition range that includes the Heusler alloy Co2MnGe, using microbeam anomalous x-ray diffraction techniques. The structural and chemical ordering of the alloy has been found to be extremely stable over a large composition range, while elemental site swapping and sublattice vacancies have been identified. A model of anomalous diffraction around the Co and Ge edges is presented and shown to make possible the identification and quantification of these disorders in an epitaxial film.
Integration of functional epitaxial oxides into silicon: From high-K application to nanostructures
Authors: Osten H. J. , Kühne D. , Laha A. , Czernohorsky M. , Bugiel E. , Fissel A.
Published: June 2007

The authors will present results for crystalline lanthanide oxides on silicon with the Ln2O3 composition (Ln=Pr, Nd, and Gd) in the cubic bixbyite structure grown by solid state molecular beam epitaxy. On Si(100) oriented surfaces, crystalline Ln2O3 grows as (110)-oriented domains, with two orthogonal in-plane orientations. Layers grown under best vacuum conditions often exhibit poor dielectric properties due to the formation of crystalline interfacial silicide inclusions. Additional oxygen supply during growth improves the dielectric properties significantly. Experimental results for Ln2O3-based metal-oxide-semiconductor (MOS) capacitors grown under optimized conditions show that these layers are excellent candidates for application as very thin high-K materials replacing SiO2 in future MOS devices. In addition, they will present a new approach for nanostructure formation which is based on solid-phase epitaxy of the Si quantum well combined with simultaneous vapor-phase epitaxy of the insulator on top of the quantum well. Ultrathin single-crystalline Si buried in a single-crystalline insulator matrix with sharp interfaces was obtained by this approach on Si(111). Finally, the incorporation of crystalline Si islands into single-crystalline oxide layers will be demonstrated.
Optical studies of molecular beam epitaxy grown GaAsSbN∕GaAs single quantum well structures
Authors: Nunna Kalyan , Iyer S. , Wu L. , Bharatan S. , Li Jia , Bajaj K. K. , Wei X. , Senger R. T.
Published: June 2007

In this work, the authors present a systematic study on the variation of the structural and the optical properties of GaAsSbN∕GaAs single quantum wells (SQWs) as a function of nitrogen concentration. These SQW layers were grown by the solid source molecular beam epitaxial technique. A maximum reduction of 328meV in the photoluminescence (PL) peak energy of GaAsSbN was observed with respect to the reference GaAsSb QW. 8K and RT PL peak energies of 0.774eV (FWHM of ∼25meV) and 0.729eV (FWHM of ∼67meV) (FWHM denotes full width at half maximum) corresponding to the emission wavelengths of 1.6 and 1.7μm, respectively, have been achieved for a GaAsSbN SQW of N∼1.4%. The pronounced S-curve behavior of the PL spectra at low temperatures is a signature of exciton localization, which is found to decrease from 16to9meV with increasing N concentration of 0.9%–2.5%. The diamagnetic shift of 13meV observed in the magnetophotoluminescence spectra of the nitride sample with N∼1.4% is smaller in comparison to the value of 28meV in the non-nitride sample, indicative of an enhancement in the electron effective mass in the nitride QWs. Electron effective mass of 0.065mo has been estimated for a SQW with N∼1.4% using the band anticrossing model.
Process for scanning near-field microwave microscope probes with integrated ultratall coaxial tips
Authors: Wang Yaqiang , Bettermann Alan D. , van der Weide Daniel W.
Published: June 2007

The authors report a process for constructing a scanning near-field microwave microscope (SNMM) probe based on microelectromechanical systems technology. The SNMM probe is capable of performing as a multifunctional scanning probe microscope. Mechanically, it consists of a diving-board-like cantilever with an integrated, ultratall (>50μm) silicon tip and is interchangeable with typical commercial atomic force microscope probes. Electrically, it employs a coplanar waveguide running from the contact pads on a high-resistivity silicon chip body onto the cantilever and out to the ultratall coaxial tip at the free end of the cantilever. The ultratall coaxial tip functions as an electrically small antenna for scanning microwave microscopy applications, as well as simultaneously permitting atomic force microscopy to be carried out. The fabrication procedure and results are described, along with preliminary microwave measurements.
Crystallographic wing tilt and thermal-stress distribution of GaN laterally overgrown on maskless V-grooved sapphire substrate by metal-organic chemical vapor deposition
Authors: Xing Zhigang , Wang J. , Wang Y. , Wang X. H. , Zhou Z. T. , Chen H. , Zhou J. M.
Published: June 2007

The crystallographic wing tilt, commonly observed for laterally overgrown GaN films, has been essentially overcome by the authors’ newly developed GaN lateral-epitaxial overgrowth (LEO) method or the so-called cantibridge epitaxy (CBE), which employs a maskless V-grooved c-plane sapphire as the substrate. The absence of the void between the coalesced wings in the CBE GaN films is found to be a key factor for the elimination of the wing tilt in the absence of any mask material. Finite element analysis is performed for voided and nonvoided CBE GaN samples. This analysis verified the correlation between the coalescence void and the crystallographic wing tilt. Thermal-stress distribution in the GaN film is presented as well. The agreement between the measured and simulated tilt angles denotes that the essence of the crystallographic wing tilt in the maskless LEO GaN films is not the same as that of the conventional LEO GaN film with a mask, which did not develop during the epitaxy process, but instead in the cooldown after growth. The crystallographic tilt angle and the stress fluctuation have been drastically suppressed, even in the voided CBE GaN film. Additional micro-Raman mapping measurements also give results in agreement with the simulated thermal-stress distribution.