bluuebunny/crossref_metadata_2025 huggingface dataset:
Fatty acid composition and organoleptic quality of four clones of durian (Durio zibethinus, murr.)
Authors: Berry Shiv K.
Published: May 2008

This study was undertaken to determine and relate the lipid content and fatty acid composition of four different durian (Durio zibethinus, Murr.) clones, i.e., D24, D2, D66 and D8, with their respective organoleptic scores. Both lipid content and the fatty acid composition were found to vary among these clones. Clones D24 and D2, which contained a higher proportion of lipids but lower unsaturated fatty acid contents, received high organoleptic scores when compared to clones D66 and D8. It was found that the lower the palmitic: palmitoleic acid ratio in the lipid of a durian clone, the higher its organoleptic quality.
Problems in understanding the interaction of surfactant, oil and water
Authors: Little R. C.
Published: May 2008

The limited partition coefficient data presently available on amphiphilic compounds precludes the serious testing of the HOR concept, especially any correlation that it may have with HLB. The HLB scale, on the other hand, has been evolved for complex amphiphile mixtures rather than pure amphiphiles, further complicating the development of a correlation between HLB and other amphiphile‐system properties. The paucity of reliable data, then, on the partition coefficient, EACN concept and HLB, especially with respect to reasonably well defined amphiphiles, greatly impedes progress in the development of a rational basis relating surfactant function to molecular structure. The effect of oil, however, in the oil‐water‐amphiphile system might be assessed through use of the solubility parameter concept since the original HLB scale was based on the stability of a specific oil‐water emulsion. Thus, while the physico‐chemical methods exist to quantitatively establish surfactant‐wateroil behavior and to test current theories and correlations, progress in this area must await the cataloging of reliable physicochemical data on reasonably well defined amphiphiles.
The Causes and Impact of the African Debt Crisis
Authors: Danso Alex
Published: May 2008

This article examines the African debt crisis. It focuses on factors leading to the accumulation of the debts and their impact on the debtor nations.

The significance of the study lies in the fact that the African debt burden presents a gruesome picture of hopelessness. This is reflected by the continent's massive debt of $230 billion, equivalent to almost three times the continent's annual export earnings. This is expected to jump to $550 billion by the year 2000. Africa's crushing debt burden has become one of the most important factors constraining recovery and development. As the United Nations Children's Fund estimates, one thousand people die each day in Africa because of the debt crisis.

The analysis shows that due to the multifaceted nature of the causes of the debt crisis, both creditors and debtors should agree on the options for dealing with the crisis. It further shows that there is the urgency for Africa to tackle its numerous sociopolitico-economic problems. Africa can make real economic progress only when it begins to get on top of its debt crisis.
Occupation Equity: A Black and White Portrait of Women in the United States Military
Authors: Cheatham Harold E. , Seem Susan R.
Published: May 2008

This study examines U.S. military occupation equity with a special focus on African-American women. The dependent variable was occupation category. A three-way interaction of race by gender by mental group was found, making untenable the contention that mental group solely predicts personnel assignment to occupation category. Women, and particularly African-American women, are underrepresented in the core, technical occupations and overrepresented in the nontechnical, support occupations examined in this study. The opposite is true for white men. Social and psychological factors are postulated regarding women's disproportionate employment in traditionally female and lower status occupations.
Linkages between Minority Business Characteristics and Minority Banks’ Locations
Authors: Cole John A. , Reuben Lucy J.
Published: May 2008

This study presents evidence regarding differences in the financial characteristics of minority business enterprises (MBEs), contingent upon whether or not they are currently located in markets which contain minority banks. We employed Dun and Bradstreet financial data for the period 1975–83. We concluded that, on average, MBES not located in markets with minority banks were larger than the bank-related MBES, laid greater emphasis on fixed assets, and financed their businesses with more equity. The bank-related MBES apparently had greater access to debt financing and operated with greater liquidity.
Minority Business Development: An International Comparison
Authors: Chen Gavin M.
Published: May 2008

The migration of people from the developing nations to the industrialized world has created significant minority population concentrations in those industrialized countries. Invariably, the minority population (generally black, Hispanic, and/or Asian) occupies the lower end of the socioeconomic distribution spectrum because of lower levels of educational achievement and higher unemployment rates. The host countries confronted with these issues of minority inequities are exploring a variety of alternatives to alleviate the socioeconomic problems; one of which is minority business development. This article looks at the industrialized countries of Canada, France, Great Britain, Holland, West Germany, and the United States, and how they are addressing the issue of minority business development. The size and diversity of the minority population, the economic, social, and political conditions under which they migrate, and the host country recognition of their status affects the economic climate and the development success of this business sector, formed outside of their native habitats. Although conditions differ from country to country, minority businesses in general suffer from similar problems of capital access, market restrictions, and general management inadequacies. The developmental path of these business sectors are, however, affected by the host country policy and the official programs designed specifically to address their needs.
Exploitation and Inefficiency in Cameroon Food Marketing Systems–Myth or Reality?: Some Evidence from the West Province
Authors: Boyer Neil A. , Davis Carlton G.
Published: May 2008

Urbanization and the food crisis have contributed to increased allegations of consumer exploitation and inefficiency in African food marketing systems. This article investigates the question of consumer exploitation and inefficiency in the food crop marketing system of the West Province of Cameroon. Exploitation is evaluated in terms of net marketing margin, and efficiency in terms of the provision of foodstuffs at competitive prices, consistent with the cost of moving commodities from producers to consumers, under prevailing conditions. Multiple regression models are employed to evaluate the determinants of gross marketing margins for vendors of four food commodities—plantain, maize, tomato, and potato. Findings suggest that the food marketing system is highly competitive with no formal entry barriers, and that allegations of consumer exploitation are largely unfounded. Given the multiplicity of economic constraints facing food vendors, they appear to carry out their marketing functions with a surprising degree of efficiency.
Acute Management of Hemodynamically Unstable Pelvic Trauma Patients: Time for a Change? Multicenter Review of Recent Practice
Authors: Verbeek Diederik , Sugrue Michael , Balogh Zsolt , Cass Danny , Civil Ian , Harris Ian , Kossmann Thomas , Leibman Steve , Malka Valerie , Pohl Anthony , Rao Sudhakar , Richardson Martin , Schuetz Michael , Ursic Caesar , Wills Vanessa
Published: May 2008

Background

Hemorrhage‐related mortality (HRM) associated with pelvic fractures continues to challenge trauma care. This study describes the management and outcome of hemodynamically unstable patients with a pelvic fracture, with emphasis on primary intervention for hemorrhage control and HRM.

Methods

Blunt trauma patients [Injury Severity Score (ISS) ≥16] with a major pelvic fracture (Abbreviated Injury Score, pelvis ≥3) and hemodynamic instability [admission systolic blood pressure (SBP) ≤90 mmHg or receiving ≥6 units of packed red blood cells (PRBCs)/24 hours) were included into a 48‐month (ending in December 2003) multicenter retrospective study of 11 major trauma centers. Data are presented as the mean ± SD.

Results

A total of 217 patients (mean age 41 ± 19 years, 71% male, ISS 42 ± 16) were studied. The admission SBP was 96 ± 37 mmHg and the Glascow Coma Scale (GCS) 11 ± 5. Patients received 4 ± 2 liters of fluids including 4 ± 4 units of PRBCs in the emergency room (ER). In total, 69 (32%) patients died, among whom the HRM was 19%; 29% of the deaths were due to pelvic bleeding. Altogether, 120 of the 217 (55%) patients underwent focused abdominal sonography for trauma (FAST) or diagnostic peritoneal aspiration (DPA) and diagnostic peritoneal lavage (DPL); 60 of the 217 (28%) patients were found to have pelvic binding in the ER. In all, 53 of 109 (49%) patients had no bleeding noted at laparotomy, 26 of 106 (25%) had no abdominal findings, and 15 of 53 (28%) had had no prior abdominal investigation (FAST/DPL/computed tomography). Angiography was positive in 48 of 58 (83%) patients. The HRM was highest in patients with laparotomy as the primary intervention (29%) followed by the angiography group (18%), the combined laparotomy/pelvic fixation group (16%), and the pelvic fixation‐only group (10%).

Conclusion

HRM associated with major pelvic trauma is unacceptably high especially in the laparotomy group. Hence, nontherapeutic laparotomy must be avoided, concentrating instead on arresting pelvic hemorrhage. Standards of care must be implemented and abided by.
Cytoprotective activity of annphenone against oxidative stress‐induced apoptosis in V79‐4 lung fibroblast cells
Authors: Shin Jung Sook , Kang Kyoung Ah , Kim Eun Sil , Zhang Rui , Piao Mei Jing , Ko Dong Ok , Wang Zhi Hong , Maeng Young Hee , Eun Su Yong , Chae Sungwook , Chung Ha Sook , Hyun Jin Won
Published: May 2008

We have elucidated the cytoprotective effect of annphenone (2,4‐dihyroxy‐6‐methoxy‐acetophenone 4‐O‐β‐d‐glucopyranoside) against oxidative stress‐induced apoptosis. Annphenone scavenged intracellular reactive oxygen species (ROS) and increased antioxidant enzyme activities. It thereby prevented lipid peroxidation and DNA damage, which was demonstrated by the inhibition of the formation of thiobarbituric acid reactive substance (TBARS), inhibition of the comet tail and decreased phospho‐H2A.X expression. Annphenone protected Chinese hamster lung fibroblast (V79‐4) cells from cell death via the inhibition of apoptosis induced by hydrogen peroxide (H2O2), as shown by decreased apoptotic nuclear fragmentation, decreased sub‐G1cell population and inhibited mitochondrial membrane potential (Δ∍) loss. Taken together, these findings suggest that annphenone exhibits antioxidant properties by inhibiting ROS generation and thus protecting cells from H2O2‐induced cell damage.
Legal provisions and practice in the management of violent patients. A case vignette study in 16 European countries
Authors: Steinert Tilman , Lepping Peter
Published: May 2008

Aim

To compare the clinical management of typical scenarios by using three case vignettes in a substantial number of European countries.

Method

Three case vignettes and an associated questionnaire, filled in and finalised by at least two experts from each country.

Results

Legislation and clinical practice varies widely across the 16 included countries. No specific pattern emerged. Certain practices (intravenous medication, mechanical restraint, net beds and forensic transfers, respectively) only exist in few countries. Legislation for involuntary medication is most restrictive in the Netherlands.

Conclusions

There is little harmonisation and a lack of consistent standards within and across European countries regarding treatment and management of violent patients.
High molecular weight adiponectin activates AMPK and suppresses cytokine‐induced NF‐κB activation in vascular endothelial cells
Authors: Hattori Yoshiyuki , Nakano Yasuko , Hattori Sachiko , Tomizawa Atsuko , Inukai Kouichi , Kasai Kiuo
Published: May 2008

Various isoforms of adiponectin circulate in the plasma. We purified high molecular weight (HMW) adiponectin from human plasma. HMW adiponectin was observed to activate AMP‐activated protein kinase (AMPK), thereby increasing the phosphorylation of eNOS and NO production in endothelial cells. On the other hand, cells preincubated with HMW adiponectin had reduced TNFα‐induced NF‐κB activation. HMW adiponectin by itself was found to modestly activate NF‐κB, which was significantly enhanced by inhibition of AMPK/eNOS activation. Thus, HMW adiponectin might have dual action, both pro and anti‐inflammatory. An initial period of NF‐κB activation by HMW adiponectin might be proinflammatory, but it could be counteracted by activation of AMPK/eNOS, which lead to a potential reduction in a second activation of NF‐κB against inflammatory stimuli.
Multiple red cell transfusions in 27 cats (2003–2006): Indications, complications and outcomes
Authors: Roux Françoise A. , Deschamps Jack-Yves , Blais Marie-Claude , Welsh Diane M. , Delaforcade-Buress Armelle M. , Rozanski Elizabeth A.
Published: May 2008

The objectives of this study were (1) to evaluate the indications, complications and outcomes of multiple red cell transfusions (MrcTs) in cats; of these cats (2) to describe those that received massive transfusion and (3) compare them with those who received MrcTs over a longer time course. Twenty-seven cats were identified which received a total of 110 transfusions, with a median of three transfusions (range 3–15) per cat. The transfusions consisted of 47 units of whole blood and 63 units of packed red blood cells. The median age of cats was 6 years (range 6 months to 15 years). Cats were hospitalized for a median of 6 days, with a range of 1–38 days. No acute transfusion reactions were documented, although due to the critical nature of the cats, they may not have been appreciated. Sixteen cats survived to discharge and 11 died or were euthanased. Indications (and % survival) for transfusions included bone marrow failure ( n=8; 50%); surgical loss ( n=4; 100%), sepsis ( n=3; 0%), neoplasia ( n=3; 33%), acute renal failure ( n=3; 66%), trauma ( n=2; 100%), gastrointestinal bleeding ( n=1; 100%), and cats with multiple disease processes ( n=3; 33%). MrcTs are well-tolerated in cats and may be associated with a favorable outcome.
Combined administration in a single injection of a feline multivalent modified live vaccine against FHV, FCV, and FPLV together with a recombinant FeLV vaccine is both safe and efficacious for all four major feline viral pathogens
Authors: Kanellos Theo , Sutton David J. , Salisbury Claire F. , Chalmers William Stuart K.
Published: May 2008

Nobivac Tricat, a lyophilised trivalent modified live attenuated vaccine is routinely used to protect cats against three commonly diagnosed feline viral pathogens namely herpesvirus, calicivirus and panleukopenia virus. The recognition of feline leukaemia virus (FeLV) as an important viral pathogen has prompted the development of an efficacious liquid recombinant subunit FeLV vaccine (p45 envelope protein). Lyophilised Tricat vaccine was dissolved in the liquid FeLV vaccine and no detectable deleterious effect on the titre of any of the live virus components was observed after 2h incubation. In vivo studies where the vaccines were mixed in the same syringe prior to inoculation showed no alteration to the safety profile assessed by repeat and overdose studies. Serological comparisons of the modified live viral antibody titres showed no evidence of reduced responses following administration of the mixed products. Challenge studies using pathogenic herpesvirus and FeLV revealed no difference in the degree of clinical protection. This paper shows that neither safety nor efficacy is adversely affected as a result of mixing the two vaccines.
Performance differences in property‐type diversified versus specialized real estate investment trusts (REITs)
Authors: Benefield Justin D. , Anderson Randy I. , Zumpano Leonard V.
Published: May 2008

Evidence from the corporate finance literature indicates that diversified firms trade at a discount to otherwise comparable specialized firms. However, very little research has addressed whether a similar diversification discount might exist in equity REITs that diversify across property types relative to those specializing in one property type. Using a sample of 75 equity REITs, the existence of a property‐type diversification discount is tested using standard Jensen's Alpha, Treynor Index, and Sharpe Ratio performance ranking methodologies over four commonly employed market proxies. Several variations of these standard tests are also utilized as robustness checks.
Late Quaternary sedimentology and geochronology of small playas on the Southern High Plains, Texas and New Mexico, U.S.A.
Authors: Holliday Vance T. , Mayer James H. , Fredlund Glen G.
Published: May 2008

Playas are small, circular basins forming a ubiquitous component of the southern High Plains landscape. They are filled with carbonaceous mud deposited since the terminal Pleistocene. The stratigraphy and geochronology of 30 playas was investigated to better understand the paleoenvironmental record of basin filling. At the base of the fill in some playas is a well sorted eolian sand dated between ~ 13,000 and ~ 11,00014C yr BP. The beginning of mud deposition, representing aggradation of eolian dust on a moist, vegetated playa floor was largely between ~ 12,000 and ~ 10,50014C yr BP. Playa filling slowed ~ 9000 to ~ 400014C yr BP, probably due to dry conditions, increased ~ 4000 to ~ 200014C yr BP, then slowed again. Eolian sand and loam, likely representing regional aridity, accumulated in some basins episodically just prior to ~ 10,70014C yr BP, between ~ 8600 and ~ 470014C yr BP, and at ~ 130014C yr BP. Stable C isotopes from one basin indicate that the playa was inundated only seasonally throughout the record beginning ~ 11,50014C yr BP. The phytolith record in that basin indicates an abrupt shift toward cooling ~ 11,400 to ~ 11,20014C yr BP and then increasing importance of xeric-adapted C4grasses through the Holocene.
The Politics of Memory: Rededicating Two Historical Monuments in Postwar Germany
Authors: Mustafa Sam A.
Published: May 2008

For much of the past two centuries German governments encouraged or even sponsored the construction of war monuments. By the turn of the twentieth century Germany was covered in more than a thousand such shrines, most of which had local or regional significance as places of annual celebration or commemoration. Government, media, and business all contributed to an elaborate hagiography of Germany's battles, war heroes, and martyrs, with monuments usually serving as the centerpieces. Millions of middle-class Germans attended or participated in commemoration ceremonies at war monuments all over the country, and/or filled their homes with souvenir trinkets, tableware, wall decorations, coffee-table books, and other quotidian items that reproduced images of the monuments or scenes from the events they memorialized.
Evolution of the glacial landscape of the Southern Alps of New Zealand: Insights from a glacial erosion model
Authors: Herman Frédéric , Braun Jean
Published: May 2008

A new version of a landscape evolution model that includes the evolution of an ice cap at a 103 to 105 year timescale and its associated erosion patterns is presented and applied to the Southern Alps of New Zealand. Modeling of the ice cap evolution is performed on a higher‐resolution grid (i.e., ∼100 m) than previously (Braun et al., 1998). It predicts which parts of the landscape are, and have been, affected by glacial erosion. The model results highlight the complexity of the erosion patterns induced by ice caps and glaciers. Glacial erosion in a tectonically active area is, as suggested by the model, not uniform across the mountain range. Furthermore, high rock uplift rates, heavy precipitation, and climatic oscillations constantly interact. The feedback mechanisms are such that they render the landform very dynamic and transient. However, under conditions of reduced rock uplift rate and precipitation, the landform becomes more stable at the timescale of the glacial cycle. Finally, the modeling results favor a tectonic model in the Southern Alps in which the maximum rock uplift is offset from the Alpine Fault.
An improved neighborhood algorithm: Parameter conditions and dynamic scaling
Authors: Wathelet M.
Published: May 2008

The Neighborhood Algorithm (NA) is a popular direct search inversion technique. For dispersion curve inversion, physical conditions between parameters Vs and Vp (linked by Poisson's ratio) may limit the parameter space with complex boundaries. Other conditions may come from prior information about the geological structure. Irregular limits are not natively handled by classical search algorithms. In this paper, we extend the NA formulation to such parameter spaces. For problems affected by non‐uniqueness, the ideal solution is made of the ensemble of all models that equally fits the data and prior information. Hence, a powerful exploration tool is required. Exploiting the properties of the Voronoi cells, we show that a dynamic scaling of the parameters during the convergence to the solutions drastically improves the exploration.
Reduction of the hyporheic zone volume due to the stream‐aquifer interaction
Authors: Boano Fulvio , Revelli Roberto , Ridolfi Luca
Published: May 2008

Pore water in stream sediments is continuously exchanged with the surface water from the overlying stream. This exchange of water and solutes that occurs across the stream‐sediment interface plays an important role for fluvial ecology because of the unique biochemical conditions, rich biodiversity, and high rates of metabolism. While many studies have observed the extent of the hyporheic zone to be modified by changes in the level of the groundwater table, the actual importance of this interaction is still difficult to quantify. Here, we focus on the case of bedform induced hyporheic exchange to show how the the volume of hyporheic sediments that receive water from the stream is significantly reduced by the upwelling of subsurface water. A simple scaling relationship for the assessment of maximum depth of the hyporheic zone is proposed by relating hyporheic flow to the groundwater discharge in an aquifer with given hydraulic properties and head difference between the stream and the aquifer.
Retracted: Switching of chromatin‐remodelling complexes for oestrogen receptor‐α
Authors: Okada Maiko , Takezawa Shin‐ichiro , Mezaki Yoshihiro , Yamaoka Ikuko , Takada Ichiro , Kitagawa Hirochika , Kato Shigeaki
Published: May 2008

The female sex steroid hormone oestrogen stimulates both cell proliferation and cell differentiation in target tissues. These biological actions are mediated primarily through nuclear oestrogen receptors (ERs). The ligand‐dependent transactivation of ERs requires several nuclear co‐regulator complexes; however, the cell‐cycle‐dependent associations of these complexes are poorly understood. By using a synchronization system, we found that the transactivation function of ERα at G2/M was lowered. Biochemical approaches showed that ERα associated with two discrete classes of ATP‐dependent chromatin‐remodelling complex in a cell‐cycle‐dependent manner. The components of the NuRD‐type complex were identified as G2/M‐phase‐specific ERα co‐repressors. Thus, our results indicate that the transactivation function of ERα is cell‐cycle dependent and is coupled with a cell‐cycle‐dependent association of chromatin‐remodelling complexes.
Atrophin recruits HDAC1/2 and G9a to modify histone H3K9 and to determine cell fates
Authors: Wang Lei , Charroux Bernard , Kerridge Stephen , Tsai Chih‐Cheng
Published: May 2008

Atrophin family proteins, including the vertebrate arginine–glutamic acid dipeptide repeats protein (RERE) and Drosophila Atrophin (Atro), constitute a new class of nuclear receptor corepressors. Both RERE and Atro share the ELM2 (EGL‐27 and MTA1 homology 2) and SANT (SWI3/ADA2/N‐CoR/TFIII‐B) domains, which are also present in other important transcriptional cofactors. Here, we report that the SANT domain in RERE binds to the histone methyltransferase G9a, and that both the ELM2 and SANT domains orchestrate molecular events that lead to a stable methylation of histone H3‐lysine 9. We establish the physiological relevance of these interactions among Atrophin, G9a, and histone deacetylases 1 and 2 in Drosophila by showing that these proteins localize to overlapping chromosomal loci, and act together to suppress wing vein and melanotic‐mass formation. This study not only shows a new function of the SANT domain and establishes its connection with the ELM2 domain, but also implies that a similar strategy is used by other ELM2–SANT proteins to repress gene transcription and to exert biological effects.
A transcription cofactor required for the heat‐shock response
Authors: Xu Danmei , Zalmas L Panagiotis , La Thangue Nicholas B
Published: May 2008

The Stress‐responsive activator of p300 (Strap) is a transcription cofactor that has an important role in the control of DNA damage response through its ability to regulate p53 activity. Here, we report that Strap is inducible by heat shock and stimulates the transcription of heat‐shock genes. A chromatin‐associated complex involving heat‐shock factor 1 (HSF1), Strap and the p300 coactivator assembles on the heat‐shock protein 70 (hsp70) promoter, and Strap augments HSF1 binding and chromatin acetylation in Hsp genes, most probably through the p300 histone acetyltransferase. Cells depleted of Strap do not survive under heat‐shock conditions. These results indicate that Strap is an essential cofactor that acts at the level of chromatin control to regulate heat‐shock‐responsive transcription.
Relationships of body mass index with serum carotenoids, tocopherols and retinol at steady-state and in response to a carotenoid-rich vegetable diet intervention in Filipino schoolchildren
Authors: Ribaya-Mercado Judy D. , Maramag Cherry C. , Tengco Lorena W. , Blumberg Jeffrey B. , Solon Florentino S.
Published: May 2008

In marginally nourished children, information is scarce regarding the circulating concentrations of carotenoids and tocopherols, and physiological factors influencing their circulating levels. We determined the serum concentrations of carotenoids, tocopherols and retinol at steady state and in response to a 9-week vegetable diet intervention in 9–12-year-old girls (n=54) and boys (n=65) in rural Philippines. We determined cross-sectional relationships of BMI (body mass index) with serum micronutrient levels, and whether BMI is a determinant of serum carotenoid responses to the ingestion of carotenoid-rich vegetables. We measured dietary nutrient intakes and assessed inflammation by measurement of serum C-reactive protein levels. The children had low serum concentrations of carotenoids, tocopherols and retinol as compared with published values for similar-aged children in the U.S.A. The low serum retinol levels can be ascribed to inadequate diets and were not the result of confounding due to inflammation. Significant inverse correlations of BMI and serum all-trans-β-carotene, 13-cis-β-carotene, α-carotene, lutein, zeaxanthin and α-tocopherol (but not β-cryptoxanthin, lycopene and retinol) were observed among girls at baseline. The dietary intervention markedly enhanced the serum concentrations of all carotenoids. Changes in serum all-trans-β-carotene and α-carotene (but not changes in lutein, zeaxanthin and β-cryptoxanthin) in response to the dietary intervention were inversely associated with BMI in girls and boys. Thus, in Filipino school-aged children, BMI is inversely related to the steady-state serum concentrations of certain carotenoids and vitamin E, but not vitamin A, and is a determinant of serum β- and α-carotene responses, but not xanthophyll responses, to the ingestion of carotenoid-rich vegetable meals.
Enhanced expression and activation of pro-inflammatory transcription factors distinguish aneurysmal from atherosclerotic aorta: IL-6- and IL-8-dominated inflammatory responses prevail in the human aneurysm
Authors: Lindeman Jan H. N. , Abdul-Hussien Hazem , Schaapherder Alexander F. M. , VAN Bockel J. Hajo , VON DER Thüsen Jan H. , Roelen Dave L. , Kleemann Robert
Published: May 2008

Inflammation plays a key role in the pathogenesis of an AAA (abdominal aortic aneurysm); however, the nature of the inflammatory factors and cellular response(s) involved in AAA growth is controversial. In the present study, we set out to determine the aortic levels of inflammatory cytokines in relation to downstream inflammatory transcription factors and cellular responses. A comparison of AAA wall samples with atherosclerotic wall samples taken from the same aortic region allowed AAA-specific inflammatory parameters to be identified that distinguish AAAs from ASD (aortic atherosclerotic disease). RT-PCR (real-time PCR), ELISA, Western blotting and immunohistochemistry were combined to assess cytokines and transcription factors at the mRNA and protein level, and their activation status. Compared with ASD, inflammatory parameters associated with Th1-type [T-bet, IL (interleukin)-2, IFN-γ (interferon-γ), TNF-α (tumour necrosis factor-α), IL-1α and cytotoxic T-cells] and Th2-type [GATA3, IL-4, IL-10, IL-13 and B-cells] responses were all increased in AAA samples. Evaluation of major downstream inflammatory transcription factors revealed higher baseline levels of C/EBP (CCAAT/enhancer-binding protein) α, β and δ in the AAA samples. Baseline p65 NF-κB (nuclear factor κB) and c-Jun [AP-1 (activator protein-1)] levels were comparable, but their activated forms were strongly increased in the AAA samples. Downstream target genes of p65 NF-κB, c-Jun, IL-6 and IL-8 were hyperexpressed. Molecular and cellular processes associated with IL-6 and IL-8 hyperactivation were enhanced in the AAA samples, i.e. the expression of phospho-STAT-3 (signal transducer and activator of transcription-3) and perforin were elevated, and the content of plasma cells, neutrophils and vasa vasorum was increased. In conclusion, our findings demonstrate that an AAA is a general inflammatory condition which is characterized by enhanced expression and activation of pro-inflammatory transcription factors, accompanied by IL-6 and IL-8 hyperexpression and exaggerated downstream cellular responses, which together clearly distinguish an AAA from ASD.
Investigation of the origin of deep levels in CdTe doped with Bi
Authors: Saucedo E. , Franc J. , Elhadidy H. , Horodysky P. , Ruiz C. M. , Bermúdez V. , Sochinskii N. V.
Published: May 2008

Combining optical (low temperature photoluminescence), electrical (thermoelectric effect spectroscopy), and structural (synchrotron X-ray powder diffraction) methods, the defect structure of CdTe doped with Bi was studied in crystals with dopant concentration in the range of 1017–1019at.∕cm3. The semi-insulating state observed in crystals with low Bi concentration is assigned to the formation of a shallow donor level and a deep donor recombination center. Studying the evolution of lattice parameter with temperature, we postulate that the deep center is formed by a Te–Te dimer and their formation is explained by a tetrahedral to octahedral distortion, due to the introduction of Bi in the CdTe lattice. We also shows that this model agrees with the electrical, optical, and transport charge properties of the samples.
Field dependence of the carrier injection mechanisms in InGaN Quantum wells: Its effect on the luminescence properties of blue light emitting diodes
Authors: Rossi F. , Salviati G. , Pavesi M. , Manfredi M. , Meneghini M. , Zanoni E. , Zehnder U.
Published: May 2008

Carrier injection and radiative recombination processes in InGaN∕GaN blue light emitting diodes are investigated by bias-dependent cathodoluminescence. The samples are designed with a single-quantum-well (SQW) light emitter and an adjacent multi-quantum-well (MQW) carrier injector of lower In content. In unbiased samples, the MQW emission dominates over the SQW at high temperatures (T>160K) or low beam currents (IB<5nA). This is ascribed to changes in the device energy band diagram, dependent on the field in the p-n junction and on the level of electron beam induced excitation of excess carriers. A field screening, resulting in a forward biasing of the devices, is highlighted. A maximum value of +2.65V is reached at T=100K for a carrier generation rate G0∼5.4×1013s−1. At a fixed electron beam power, the effects of an external applied field on the emitter efficiency are considered. The SQW emission is promoted in the forward-current regime, while in the reverse-current regime (−1⩽V<2.65 at T=100K) it undergoes a quenching of at least one order of magnitude and a blueshift (60meV at T=100K) due to a partial compensation between the junction field and the internal piezoelectric field (minimum residual field of about 1.9MV∕cm at T=100K). The observed blueshift is in a fairly good agreement with the voltage dependence predicted by calculating the energy band profiles and SQW confined states with a self-consistent Schrödinger–Poisson solver.
Thermal resistance between low-dimensional nanostructures and semi-infinite media
Authors: Panzer Matthew A. , Goodson Ken E.
Published: May 2008

Nanostructured electronic and photonic devices include a high density of material interfaces, which can strongly impede heat conduction and influence performance and reliability. Thermal conduction through interfaces is a very mature discipline for the traditional geometry, in which the lateral interface dimensions are large compared to the phonon wavelength. In nanostructures, however, the localization of phonons in the directions parallel to the interface may strongly influence the effective thermal resistance. The present work investigates model problems of abrupt junctions between a harmonic one-dimensional (1D) and a three-dimensional (3D) fcc lattice and between a 1D and a two-dimensional square lattice. The abrupt change in geometry modifies the phonon modes participating in energy transmission and creates an additional thermal resistance that is comparable with that occurring due to the acoustic mismatch at the interface of bulk media. For both cases, varying the impedance mismatch at the junction suggests that engineering an intentional impedance mismatch at a nanostructured interface may enhance the transmission of energy. The lattice dynamics calculations are used to develop qualitative arguments for the interface resistances in the practical geometries involving carbon nanotubes, silicon nanopillars, and graphene. This research provides foundations for detailed investigations of the impact of localized phonon modes on the acoustic mismatch resistance.
Epitaxial growth of La0.7Ba0.3MnO3 thin films on MgO substrates: Structural, magnetic, and transport properties
Authors: Orgiani P. , Adamo C. , Barone C. , Galdi A. , Pagano S. , Petrov A. Yu. , Quaranta O. , Aruta C. , Ciancio R. , Polichetti M. , Zola D. , Maritato L.
Published: May 2008

We report on structural, magnetic, and transport properties of La0.7Ba0.3MnO3 thin films, epitaxially grown on MgO substrates. Despite the quite similar structural features if compared to crystalline manganite films, our samples show a metal-insulator transition temperature of about 200K, sizeably lower than the bulk-value (TMI≃345K). Moreover, the magnetotransport properties show the absence of saturation in the magnetoresistance and localization phenomena at low temperatures (T<30K). The temperature behavior of the magnetization shows a Curie temperature Tc value above room temperature, ruling out effects due to oxygen deficiency. All these findings are analyzed in terms of possible physical mechanisms related to the growth in the presence of large mismatch between film and substrate lattice parameters.
Insight into electronic mechanisms of nanosecond-laser ablation of silicon
Authors: Marine Wladimir , Bulgakova Nadezhda M. , Patrone Lionel , Ozerov Igor
Published: May 2008

We present experimental and theoretical studies of nanosecond ArF excimer laser desorption and ablation of silicon with insight into material removal mechanisms. The experimental studies involve a comprehensive analysis of the laser-induced plume dynamics and measurements of the charge gained by the target during irradiation time. At low laser fluences, well below the melting threshold, high-energy ions with a narrow energy distribution are observed. When the fluence is increased, a thermal component of the plume is formed superimposing on the nonthermal ions, which are still abundant. The origin of these ions is discussed on the basis of two modeling approaches, thermal and electronic, and we analyze the dynamics of silicon target excitation, heating, melting, and ablation. An electronic model is developed that provides insight into the charge-carrier transport in the target. We demonstrate that, contrary to a commonly accepted opinion, a complete thermalization between the electron and lattice subsystems is not reached during the nanosecond-laser pulse action. Moreover, the charging effects can retard the melting process and have an effect on the overall target behavior and laser-induced plume dynamics.
Ruthenium nano-oxide layer in CoFe-Ru-CoFe trilayer system: An x-ray reflectivity study
Authors: Asgharizadeh S. , Sutton M. , Altounian Z. , Mao M. , Lee C. L.
Published: May 2008

A grazing incidence x-ray reflectivity technique is used to determine the electron density profile as a function of depth in CoFe-Ru-CoFe and CoFe-Ru nano-oxide layer (NOL)–CoFe trilayers. Four trilayers with ruthenium thicknesses of 8, 8.5, and 9Å and one with Ru 8.5Å NOL, prepared by a dc planetary sputtering system, were investigated. For all samples, the electron density profile (EDP) shows a central peak that is related to the Ru layer. Natural oxidation in all of the samples introduces a graded EDP of the top CoFe layers, which decreases gradually to zero. The large surface resistivity of Ru 8.5Å NOL as compared to Ru 8.5Å is related to the remarkable difference between their EDPs. EDP changes have also been investigated in Ru NOL trilayers after annealing at 280°C. The Ru phase in the EDP was observed to confirm the thermal stability of the spacer layer after annealing.
Excitonic properties of polar, semipolar, and nonpolar InGaN∕GaN strained quantum wells with potential fluctuations
Authors: Funato M. , Kawakami Y.
Published: May 2008

Excitonic properties of polar, semipolar, and nonpolar InGaN∕GaN strained quantum wells (QWs) were investigated in terms of exciton localization and polarization-induced electric fields. The spontaneous emission lifetimes measured at ∼10K for the (0001) polar QWs were 1.4ns at an emission wavelength of 400nm, but increased monotonically to 85ns at 520nm. On the other hand, those for {112¯2} and {11¯01} semipolar QWs and {112¯0} and {11¯00} nonpolar QWs were on the order of a few hundred picoseconds and independent of the emission wavelength. To quantitatively discuss these results, the crystalline orientation dependence of the spontaneous emission lifetime of 1s heavy hole excitons in InGaN∕GaN QWs at 0K was calculated, when lateral confinements were considered to express well-reported potential fluctuations. It is revealed that both the crystalline orientation and lateral confinement vary the spontaneous emission lifetime by orders of magnitude. Analyses of the experimental results suggest that excitons in the (0001) polar QWs are more strongly localized as the In composition increases, but the semipolar and nonpolar QWs exhibit the opposite tendency. These tendencies are attributed to differences in the growth characteristics.
Explicitly correlated coupled cluster F12 theory with single and double excitations
Authors: Noga Jozef , Kedžuch Stanislav , Šimunek Ján , Ten-no Seiichiro
Published: May 2008

Full explicitly correlated F12 coupled cluster theory with single and double excitations and with Slater-type geminal as a correlation factor is introduced and implemented within the standard approximation. The variant “C” that does not require integrals over the commutator between the kinetic operator and the correlation factor has been used. All the necessary integrals are analytically calculated. With variant C also, first results are reported for the correlation factor being the interelectronic distance coordinate, i.e., for original R12 method. Calculations have been performed for a set of eight molecules including CH2(A11), CH4, NH3, H2O, HF, CO, N2, and F2, as well as for the constituting atoms. Atomization energies are reported too.
Nonequilibrium dynamics of laser-generated plasma channels
Authors: Petrova Tz. B. , Ladouceur H. D. , Baronavski A. P.
Published: May 2008

A time-dependent nonequilibrium kinetics model based upon the time-dependent electron Boltzmann equation coupled with an extensive air chemistry model accounting for gas heating and vibrational kinetics is developed. The model is applied to the temporal evolution of femtosecond laser-generated air plasma channels at atmospheric pressure in an external electric field. The plasma channel dynamics depend upon the initial free electron density, the initial electron energy of the plasma, and upon the externally applied electric field strength. The model predicts an electric breakdown field strength of 5–10kV∕cm with a delay time of hundreds of nanoseconds when the electron density drops to the optimum value of ∼1012–1013cm−3. The experimentally observed breakdown field is ∼5.7kV∕cm with a statistical breakdown delay time of ∼200ns. The reduction in the breakdown field strength in natural air from ∼30to5kV∕cm is attributed to a combination of processes such as enhanced ionization due to relaxation of the initial electron energy distribution function toward a Maxwellian distribution, strong electron detachment, and gas heating. The calculated electron density decay of the laser-generated plasma channel in both pure nitrogen and dry air is in good agreement with the NRL experiments. The derived rate constant for recombination in dry air is bBair=3.9×10−8cm3s−1 and in pure nitrogen it is bBN2=4.4×10−8cm3s−1. The attachment rate coefficient in dry air is ηBair=7.5×106s−1.
Nonaxisymmetric magnetorotational instability in ideal and viscous plasmas
Authors: Mikhailovskii A. B. , Lominadze J. G. , Galvão R. M. O. , Churikov A. P. , Erokhin N. N. , Smolyakov A. I. , Tsypin V. S.
Published: May 2008

The excitation of magnetorotational instability (MRI) in rotating laboratory plasmas is investigated. In contrast to astrophysical plasmas, in which gravitation plays an important role, in laboratory plasmas it can be neglected and the plasma rotation is equilibrated by the pressure gradient. The analysis is restricted to the simple model of a magnetic confinement configuration with cylindrical symmetry, in which nonaxisymmetric perturbations are investigated using the local approximation. Starting from the simplest case of an ideal plasma, the corresponding dispersion relations are derived for more complicated models including the physical effects of parallel and perpendicular viscosities. The Friemann–Rotenberg approach used for ideal plasmas is generalized for the viscous model and an analytical expression for the instability boundary is obtained. It is shown that, in addition to the standard effect of radial derivative of the rotation frequency (the Velikhov effect), which can be destabilizing or stabilizing depending on the sign of this derivative in the ideal plasma, there is a destabilizing effect proportional to the fourth power of the rotation frequency, or, what is the same, to the square of the plasma pressure gradient, and to the square of the azimuthal mode number of the perturbations. It is shown that the instability boundary also depends on the product of the plasma pressure and density gradients, which has a destabilizing effect when it is negative. In the case of parallel viscosity, the MRI looks like an ideal instability independent of viscosity, while, in the case of strong perpendicular viscosity, it is a dissipative instability with the growth rate inversely proportional to the characteristic viscous decay rate. We point out, however, that the modes of the continuous range of the magnetohydrodynamics spectrum are not taken into account in this paper, and they can be more dangerous than those that are considered.
Theory of small-signal ac response of a dielectric liquid containing two groups of ions
Authors: Barbero G. , Batalioto F. , Figueiredo Neto A. M.
Published: May 2008

The analysis of Macdonald for electrolytes is generalized to the case in which two groups of ions are present. We assume that the electrolyte can be considered as a dispersion of ions in a dielectric liquid, and that the ionic recombination can be neglected. We present the differential equations governing the ionic redistribution when the liquid is subjected to an external electric field, describing the simultaneous diffusion of the two groups of ions in the presence of their own space charge fields. We investigate the influence of the ions on the impedance spectroscopy of an electrolytic cell. In the analysis, we assume that each group of ions have equal mobility, the electrodes perfectly block and that the adsorption phenomena can be neglected. In this framework, it is shown that the real part of the electrical impedance of the cell has a frequency dependence presenting two plateaux, related to a type of ambipolar and free diffusion coefficients. The importance of the considered problem on the ionic characterization performed by means of the impedance spectroscopy technique was discussed.
Growth and spectral analysis of ZnO nanotubes
Authors: Xu C. X. , Zhu G. P. , Li X. , Yang Y. , Tan S. T. , Sun X. W. , Lincoln C. , Smith T. A.
Published: May 2008

ZnO nanotubes were fabricated by vapor-phase transport using the mixture of ZnO and graphite powders in air. A self-catalyzed growth mechanism was proposed based on microstructure analysis by scanning electron microscopy, transmission electron microscopy, and x-ray diffraction. Raman scattering, integrated photoluminescence, and time-resolved photoluminescence were employed to explore the optical properties and the dynamic process. Combing with crystal structure and the spectral characteristics of the ZnO nanotubes, the charge carrier transport process was discussed.
Influence of microstructure on permeability dispersion and power loss of NiZn ferrite
Authors: Su Hua , Zhang Huaiwu , Tang Xiaoli , Jing Yulan
Published: May 2008

Permeability spectra of NiZn ferrite with different microstructures had been resolved into contributions of domain wall resonance and spin rotation relaxation. The fitting results of permeability dispersion revealed the relationships among domain wall resonance, spin rotation relaxation mechanisms, and microstructures. Pcv (power loss) was analyzed by dividing Pcv into Ph (hysteresis loss) and Pe+Pr (eddy current loss and residual loss) from the frequency dependence of the power loss. When excited under large flux density, sample with larger average grain size and closed pores could obtain lower Pcv. This could be attributed to the fact that closed pores were not easy to block domain wall movement and grain boundaries became the predominant domain wall pinning factor. However, for the low induction condition, sample with small grain size had better performance on Pcv due to the fact that influence of the closed pores was more significant. With increasing frequency, Pe+Pr gradually became the predominant factors in Pcv, so the sample with small grain size was more suitable for high-frequency use.