bluuebunny/crossref_metadata_2025 huggingface dataset:
Knee Meniscus, Biomechanics of
Authors: Pangborn Christine A. , Athanasiou Kyriacos A.
Published: April 2006

To fully understand the function of the knee meniscus, it is important to define the characteristics of its structure and composition, and how they vary spatially within the tissue. The meniscus is an excellent example of how structure can confer function in a mechanical device. The goal of this article is to summarize current findings related to meniscal properties. Cellular, biochemical, ultrastructural, and biomechanical characteristics are compared in the different zones, depths, and topographical regions of the knee meniscus. It is important to note the wide variety of species and testing methods that have been used to evaluate such properties. These variations render difficult direct comparisons of the properties of this anisotropic and inhomogeneous tissue. Understanding the structure‐function relationships within the meniscus will lead to better design of replacements for this tissue.
Magnetic Resonance—Electrical Impedance Tomography
Authors: Eyüboğlu B. Murat
Published: April 2006

Magnetic resonance‐electrical impedance tomography (MR‐EI) is a promising new imaging modality which was magnetic flux density measurements, acquired using magnetic resonance current density imaging (MRCDI) techniques, and surface potential measurements, similar to conventional electrical impedance tomography (EIT) measurements, to reconstruct high resolution images of true conductivity. Utilizing MRCDI techniques, magnetic flux density is measured throughout the field of view at very high resolution, hence significant improvement in spatial resolution and the uniformly of sensitivity can be achieved.
Sutures
Authors: Jones C.W. , Schreuder F.B. , Walsh W.R.
Published: April 2006

Suture materials are probably the most common biomedical materials and are used to repair virtually all known body tissues. The primary role of sutures remains that of wound closure; principally the fixing of tissues in opposition in order to facilitate healing. However, the continual evolution of materials has seen the applications of sutures widen with the development of new surgical techniques necessitating a concurrent development of suturing technologies. In this chapter, we provide a brief history of sutures and examine the role of biomedical engineering in the testing and development of suturing materials and techniques, including mechanical property testing under various conditions, knot holding capacities, suturing pattern optimization, suture fixation, and anchoring techniques. The
in vivo
response of the human body to various sutures may have an important effect on the material or mechanical properties of the suture/tissue complex, including the viscoelasticity, the stress relaxation, and the strain rate. In this context, we consider the body's response to suture materials according to the inflammatory response, the histological characteristics, and the differences between absorbable and nonabsorbable suture materials. Further, we explore the emerging types of angiogenic and thrombogenic sutures in relation to the biomedical engineering practices that are being used to develop the great potential of these devices. Finally, we consider the continuing development of biomedically engineered sutures with associated advances in clinical effectiveness.
Meniscal Replacements
Authors: Haut Donahue Tammy , Maes Jason
Published: April 2006

Menisci are fibrocartilagenous structures in the knee joint that act to distribute the load from the femur to the tibia. Menisci are frequently torn as a result of sporting activity or degenerative tears associated with aging. Approximately 12.5% of annual visits to orthopedic surgeons are related to knee injury, and of those visits, 43% are directly related to meniscal injuries (see review by McBride and Reid, 1988). Some tears do not heal because they either occur in the avascular region of the meniscus or are too complex for repair. Therefore, the common treatment for these types of tears is either complete or partial meniscectomy depending on the severity of the tear. However, meniscectomies have been shown to lead to degenerative arthritis in the knee. Therefore, in an effort to prevent premature arthritis caused by removal of the meniscus or a portion of the meniscus, meniscal replacement strategies are being investigated.

This article will detail the basic structure and function of meniscal tissue and the attachments of the menisci to the surrounding structures. The strengths and weaknesses of various meniscal replacement strategies will be discussed, including autografts, meniscal allografts, synthetic prosthesis, and tissue‐engineered constructs. The success of meniscal replacements likely depends on their ability to restore normal meniscal function both biologically and biomechanically. Previous studies indicate that a number of biomechanical criteria are important for proper meniscal function, such as the material properties and geometry of the replacement tissue as well as the attachment of the replacement to the tibial plateau.
Hypertension: Time‐Frequency Analysis for Early Diagnosis
Authors: Davrath Linda , Pinhas Itzik , Toledo Eran , Akselrod Solange
Published: April 2006

Hypertension is the most common disease in industrialized nations, and it markedly increases both morbidity and mortality from cardiovascular and many other diseases. Yet, appropriate interventions can delay and possibly prevent the development of hypertension and ensuing complications. The risk of cardiovascular death doubles in a near linear fashion for each 20/10 mm Hg increment in blood pressure levels above 115/75 mm Hg. Despite this, no techniques are currently available to identify individuals at increased risk for developing hypertension. Autonomic dysfunction has been quantified at progressive stages of hypertension, providing insight into the malfunctions characteristic of pre‐hypertension, mild, and full‐blown hypertension.

Newly developed time‐frequency analysis tools provide a promising prospect for simple, noninvasive identification of individuals with a “pre‐hypertensive” profile. Early identification of individuals prone to developing hypertension may allow for aggressive early intervention to slow down, or even halt, disease progression.
Thyroid anomalies in Williams syndrome: Investigation of 95 patients
Authors: Selicorni A. , Fratoni A. , Pavesi M.A. , Bottigelli M. , Arnaboldi E. , Milani D.
Published: April 2006

Thyroid involvement in Williams syndrome (WS) was recently reported in two small groups of patients, both showing an increased prevalence of elevation of TSH serum concentration; in one of the two reports, 70% of the patients demonstrated a hypoplasia of thyroid gland as well. In our institution, we currently follow a large population of WS patients who periodically undergo a multispecialist clinical evaluation that includes ultrasound evaluation of the thyroid gland, and levels of FT3, FT4, TSH, and anti‐thyroid antibodies. Here, we report on the prevalence of thyroid structural and functional anomalies, in a population of 95 WS patients, half of them followed for more than 5 years. Our study confirms the increased incidence of both elevated TSH serum values (37.9% in our sample) and thyroid gland hypoplasia (74.7%). Moreover, we demonstrated that TSH elevation declines with age. For this reason, we suggest that a complete thyroid evaluation be performed in every patient with WS, and that this medical complication should be periodically searched for in follow‐up visits. © 2006 Wiley‐Liss, Inc.
Linkage analysis of genetic loci for kyphoscoliosis on chromosomes 5p13, 13q13.3, and 13q32
Authors: Miller Nancy H. , Marosy Beth , Justice Cristina M. , Novak Steven M. , Tang Edward Y. , Boyce Paul , Pettengil James , Doheny Kimberly F. , Pugh Elizabeth W. , Wilson Alexander F.
Published: April 2006

Kyphoscoliosis, a three‐dimensional deformity of spinal growth, is characterized by a curvature in the coronal plane (scoliosis) in conjunction with thoracic kyphosis in excess of the normal range in the sagittal plane. We identified kyphoscoliosis within members of seven families (53 individuals) originally ascertained as part of a large collaborative study of familial idiopathic scoliosis. Model‐independent linkage analysis of a genome‐wide microsatellite screen identified areas suggestive of linkage on chromosomes 2q22, 5p13, 13q, and 17q11. Single‐point and multipoint analyses of an additional 25 flanking microsatellite markers corroborated linkage to these regions, with areas on chromosomes 5p13, 13q13, and 13q32 being the most significant (P < 0.005). Analyses of single nucleotide polymorphism (SNP) markers in the candidate region on chromosome 5 narrowed the region to approximately 3.5 Mb (P < 0.05), with the most significant P values (P < 0.01) occurring in approximately a 1.3‐Mb region. Candidate loci in this region include IRX1, IRX2, and IRX4 of the Iroquois Homeobox protein family. On chromosome 13, single‐point and multipoint analyses resulted in multiple SNPs having P values < 0.05 within five candidate genes: Osteoblast‐specific factor 2 or periostin, forkhead box O1A, A‐kinase anchor protein 11, TBC1 domain family member 4, and glypican 5, thus supporting the potential relevance of this region in the pathogenesis of kyphoscoliosis. © 2006 Wiley‐Liss, Inc.
Meiotic segregation analysis of reciprocal translocations both in sperms and blastomeres
Authors: Yakut Tahsin , Ercelen Nesrin , Acar Hasan , Kimya Yalçın , Egeli Unal
Published: April 2006

Balanced chromosomal rearrangements could lead to unbalanced segregation gametes during meiosis. In this study, sperm flourescence in situ hybridization (FISH) analysis of meiotic segregation products of four reciprocal translocations; 46,XY,t(7;10)(q21;q22), 46,XY,t(15;17)(q11;p12), 46,XY,t(6;13)(p21.1;q32), and 46,XY,t(1;13)(q24;q10) are presented. In three out of these four cases with t(15;17), t(6;13), and t(1;13) additional blastomere FISH analyses are also provided. Multi‐color FISH analysis was applied using diverse probe combinations specific for translocated chromosome segments. The average frequency of sperm nuclei bearing unbalanced products for t(7;10), t(15;17), t(6;13), and t(1;13) were 48.7%, 59.5%, 60.5%, and 62.9%, respectively. Frequencies of blastomeres comprising unbalanced products in cases with t(15;17), t(6;13), and t(1;13) were 80% (12 of 15), 60% (3 of 5), and 50% (2 of 4), respectively. Chi‐square test analysis showed significant differences in the meiotic segregation patterns due to the distribution and numbers of the chiasmatas that could depend on the size of the translocated segments (P < 0.001). In conclusion, FISH analysis of sperm and blastomere for reciprocal translocation carriers effectively estimates the approximate risk of unbalanced products and this result might ensure valuable genetic counseling. © 2006 Wiley‐Liss, Inc.
Altering lipase activity and enantioselectivity in organic media using organo‐soluble bases: Implication for rate‐limiting proton transfer in acylation step
Authors: Chen Chun‐Chi , Chen Teh‐Liang , Tsai Shau‐Wei
Published: April 2006

With the hydrolytic resolution of (R,S)‐naproxen 2,2,2‐trifluoroethyl esters via a partially purified papaya lipase (PCPL) in water‐saturated isooctane as the model system, the enzyme activity, and enantioselectivty is altered by adding a variety of organo‐soluble bases that act as either enzyme activators (i.e., TEA, MP, TOA, DPA, PY, and DMA) or enzyme inhibitors (i.e., PDP, DMAP, and PP). Triethylamine (TEA) is selected as the best enzyme activator as 2.24‐fold increase of the initial rate for the (S)‐ester is obtained when adding 120 mM of the base. By using an expanded Michaelis–Menten mechanism for the acylation step, the kinetic analysis indicates that the proton transfer for the breakdown of tetrahedral intermediates to acyl‐enzyme intermediates is the rate‐limiting step, or more sensitive than that for the formation of tetrahedral intermediates when the enzyme activators of different pKa are added. However, no correlation for the proton transfers in the acylation step is found when adding the bases acting as enzyme deactivators. © 2006 Wiley Periodicals, Inc.
Selective separation of cationic peptides from a tryptic hydrolysate of β‐lactoglobulin by electrofiltration
Authors: Lapointe Jean‐François , Gauthier Sylvie F. , Pouliot Yves , Bouchard Christian
Published: April 2006

Electrofiltration (EF) was used to selectively separate cationic (basic) peptides contained in a tryptic β‐lactoglobulin (β‐LG) hydrolysate, with particular emphasis on the isolation of basic sequence β‐LG 142–148, which is a potential antihypertensive peptide. Both the influence of feed solution pH and operating parameters (transmembrane pressure, feed velocity) were assessed to find optimum conditions enabling the fractionation between peptides during EF. The cathode (−) was inserted in the permeate side to increase the separation of basic peptides contained in the tryptic β‐LG hydrolysate as compared to conventional NF. The highest separation factor between basic and neutral peptides was obtained at pH 9 using G‐10 membrane with a molecular weight cut‐off (MWCO) of 2,500 g/mol, at 5 V with the lowest transmembrane pressure (0.344 MPa) and feed velocity (0.047 m/s). The transmission behavior of the peptides during EF was better explained when taking into account the positive/negative charge ratio. Because of its 3+/1− charge ratio, β‐LG 142–148 had the highest transmission during EF. Consequently, its relative concentration was raised from 3.5% in the initial tryptic β‐LG hydrolysate up to 38% in the permeate. The electric field seemed more effective when the convective/shearing forces were minimized. © 2006 Wiley Periodicals, Inc.
Kinetics and Mechanism of Oxidation of Some Diols by Dihydroxydiperiodatoargentate(III) in Alkaline Medium
Authors: Shan Jin‐Huan , Li Sheng‐Min , Huo Shu‐Ying , Shen Shi‐Gang , Sun Han‐Wen
Published: April 2006

The kinetics of oxidation of ethylene glycol and 1,3‐butylene glycol by dihydroxydiperiodatoargentate(III) in alkaline medium have been studied by spectrophotometry in the range of 298.2–318.2 K. It is shown that the reaction was first order with respect to each reductant and Ag(III), and kobs increased with an increase of [OH−]. A plausible mechanism of reaction involving a pre‐equilibrium of adduct formation between complex and reductants was proposed, which could be applied to explain all experimental phenomena, and the activation parameters of the rate‐determining step have been also calculated.
Charge Migration in DNA: A Double Stranded Model
Authors: Bao Han , Lu Jing , Fan Kang‐Nian
Published: April 2006

In particular, charge migration phenomena in DNA have attracted much interest because of relevance to the generation of damage and mutations which play important roles in most of life processes. In this paper a theory method was presented in which the DNA chain was treated as a double‐stranded system, and the charge migration in DNA based on the donor‐bridge‐acceptor system was investigated by this model. After having obtained the Hamiltonian, the effects of the surrounding were explained and calculated. The double‐strand calculation could lead to good exponential decay curves and this time two different falloff parameters were found respectively before and after 3 or 4 AT base pair bridge lengths as prediction. Lately theoretical study showed this result by addition of more parameter, and sequence effect was then concentrated on. The difference of transfer integral caused the different decay rate of unlike sequences, but bridge length was still proved to be the main factor on the decay rates.
Cation Guided Assembly: Crystal Structures of Two Ag(I) Complexes in Versatile Dimensionalities with Different Counter Cations
Authors: Wang Jiang‐Yun , Gu Wen , Wang Wen‐Zhen , Liu Xin , Liao Dai‐Zheng
Published: April 2006

Assembly of [Ag(CN)2]− units with M(II)‐diamine complex cations [Cu(LN‐N)2]2+, where LN‐N represents 1,2‐diaminopropane (pn) and ethylenediamine (en), afforded two complexes, [Cu(pn)2][Ag2(CN)4] (1) and [Cu(en)2][Ag3(CN)5] (2), which were characterized by elemental analysis, IR, UV‐Vis and ESR spectra. Single crystal X‐ray analyses show that these complexes have 2D and 3D architectures through silver‐silver interactions and other weak interactions. The luminescence behaviors of the two complexes were also studied by means of emission spectra.
Kinetics of Thermal Decomposition of Zn1–xMnxC2O4·2H2O in Air
Authors: Cong Chang‐Jie , Hong Jian‐He , Luo Shi‐Ting , Tao Hai‐Bo , Zhang Ke‐Li
Published: April 2006

Thermal decomposition processes taking place in solid state complex of Zn1−xMnxC2O4·2H2O have been investigated in air using TG‐DTG/DTA, XRD and TEM techniques. TG‐DTG/DTA curves showed that the decomposition proceeded through two well‐defined steps with DTA peaks closely to correspond to the weight loss. XRD and TEM showed that the final decomposition product of Zn1–xMnxC2O4·2H2O was Zn1–xMnxO and most of the individual particles were of size 10–13 nm. Kinetics analysis of Zn1–xMnxC2O4·2H2O decomposition steps was performed under nonisothermal conditions, the activation energies were estimated by Friedman and Flynn‐Wall‐Ozawa (FWO) methods, and the most probable kinetic model has been estimated with multiple linear regression method. The activation energies for the two decomposition steps of Zn1–xMnxC2O4·2H2O were 155.7513 and 215.9397 kJ/mol, respectively.
Synthesis of Two Natural Oleanolic Acid Saponins
Authors: Li Chun‐Xia , Zang Jing , Wang Peng , Zhang Xiu‐Li , Guan Hua‐Shi , Li Ying‐Xia
Published: April 2006

3‐O‐[β‐D‐Glucopyranosyl‐(1→3)‐α‐L‐arabinopyranosyl]‐oleanolic acid‐28‐O‐[β‐D‐glucopyranosyl] ester 1 was synthesized concisely by a convergent strategy. Using stepwise fashion for the synthesis of saponin 2, 3‐O‐{[β‐D‐glucopyranosyl‐(1→2)]‐[α‐L‐arabinopyranosyl‐(1→3)]‐α‐L‐arabinopyranosyl}‐oleanolic acid‐28‐O‐(β‐ D‐glucopyranosyl) ester, an abnormal phenomenon, that the terminal arabinosyl residue took the 1C4 conformation instead of typical 4C1 form, was observed. Deprotection or heating could not resume the normal conformation, which resulted in the product of 2′ not 2.
Synthesis and Crystal Structure of a Tetranuclear Cubane‐like Nickel(II) Complex with 2‐Hydroxymethyl‐N‐salicylideneaniline
Authors: Liu Hui‐Yan , Wang Hai‐Ying , Shi Da‐Qing , Tian Jin‐Lei
Published: April 2006

The tetranuclear cubane‐like complex, [NiL(EtOH)]4·0.5EtOH (1) with tridentate Schiff base ligand (H2L=2‐Hydroxymethyl‐N‐salicylideneaniline) has been synthesized and its crystal structure and spectroscopic properties have been studied. The complex consists of a tetranuclear (NiO)4 cubane core, of which four nickel(II) ions are bridged by μ3‐alkoxide group and each nickel(II) ion is coordinated to three μ3‐alkoxide oxygen atoms, one imino nitrogen atom and one phenoxide oxygen atom from Schiff base ligand, and further ligated by one EtOH molecule, completing a distorted octahedral geometry.
Investigation on Voltammetric Behavior of Camptothecin and Its Analytical Application
Authors: Zheng Jian‐Bin , Meng Zu‐Chao , Liu Bo , Zhang Hong‐Fang
Published: April 2006

The voltammetric behavior of camptothecin (CPT) in Britton‐Robinson (B‐R) buffer solutions (pH 2.09–9.07) was studied by the means of linear sweep voltammetry (LSV), cyclic voltammetry (CV) and normal pulse voltammetry (NPV) at a hanging mercury drop electrode. In different pH range of B‐R buffer solutions, CPT could cause three reduction waves. In B‐R buffer solutions (pH 2.09–5.46), wave P1 yielded by CPT was a two‐electron wave. Between pH 6.01 and 9.07, CPT could yield two reduction waves P2 and P3. In addition, the pure CPT obtained from camptotheca acumina grown only in China was determined by NPV, and a linear response was observed in the range of 2.0×10−3–4.0×10−2 mmol·L−1 with a 0.9991 correlation coefficient and a 8.0×10−4 mmol·L−1 detection limit for CPT.
Covalent Functionalization of Multiwalled Carbon Nanotubes with Poly(acrylic acid)
Authors: Liu Yan‐Xin , Du Zhong‐Jie , Li Yan , Zhang Chen , Li Hang‐Quan
Published: April 2006

Covalent functionalization of multiwalled carbon nanotubes (MWNT) with poly(acrylic acid) has been successfully achieved via grafting of poly(acryloyl chloride) on nanotube surface by esterification reaction of acyl chloride‐bound polymer with hydroxyl functional groups present on acid‐oxidized MWNT and hydrolysis of polymer attached to nanotubes. Polymer‐functionalized MWNT could possess remarkably high solubility in water, and their aqueous solution was very stable without any observable black deposit for a long time. Characterizations of such functionalized MWNT samples using Fourier transform infrared spectrometer, transmission electron microscopy and nuclear magnetic resonance techniques indicated that poly(acrylic acid) was covalently attached to the surface of MWNT.
Crystal Structure and Photochromism of a Novel Organic Compound Condensed by Pyrazolone with Thiosemicarbazide
Authors: Liu Guang‐Fei , Liu Lang , Jia Dian‐Zeng , Zhang Li
Published: April 2006

A new photochromic organic compound of thiosemicarbazone, 4‐(p‐bromo‐α‐methylaminothiocarbonyl hydrazonobenzal)‐2,5‐dihydro‐3‐methyl‐5‐oxo‐1‐phenyl pyrazole, was synthesized and characterized by elemental analyses, IR, 1H NMR spectra, and X‐ray single‐crystal diffraction analysis. The compound exhibited an interesting photochromism in the solid state when irradiated by ultraviolet light at 365 nm. The photochromic kinetics was studied by the time‐dependent powder UV‐Vis reflectance spectra. The intermolecular and intramolecular hydrogen‐bonding interactions may be responsible for the photochromic phenomenon.
Improving the Enzyme Catalytic Efficiency Using Ionic Liquids with Kosmotropic Anions
Authors: Zhao Hua , Campbell Sophia , Solomon Jonathan , Song Zhi‐Yan , Olubajo Olarongbe
Published: April 2006

The kosmotropicity of cations and anions in ionic liquids has a strong influence on the enzyme catalytic efficiency in aqueous environments. The kosmotropic anion CF3COO− seemed to activate the protease, and the chaotropic anions tended to destabilize the enzyme.
Synthesis and Investigation of Soluble Polymer‐supported Dendrimers
Authors: Xie Cheng , Lu Cui‐Fen , Chen Zu‐Xing , Yang Gui‐Chun
Published: April 2006

Poly(ethylene glycol) (PEG)‐supported dendrimers have been synthesized using 2,4,6‐trichloro‐1,3,5‐triazine (TCT) as dendrons and tris(hydroxymethyl)aminomethane as linkers with high loading capacity, excellent solubility and thermal stability by divergent method. The new synthesized PEG‐supported G2.0 dendrimer has 10 times as large functional group loading capacity as commercial PEG3400 with overall yield 44.0%.
Preoperative steroid pulse therapy for invasive thymoma
Authors: Kobayashi Yoshihiro , Fujii Yoshitaka , Yano Motoki , Sasaki Hidefumi , Yukiue Haruhiro , Haneda Hiroshi , Suzuki Eriko , Endo Katsuhiko , Kawano Osamu
Published: April 2006

BACKGROUND

Glucocorticoid was used in thymomas. The purpose of the study was to evaluate the efficacy of intravenous high‐dose glucocorticoid (steroid pulse) therapy in patients with previously untreated advanced thymoma. Causes were also sought for a possible underlying mechanism of the effect of steroid on thymoma.

METHODS

Seventeen patients with invasive thymoma who had not received previous chemotherapy or radiation therapy were enrolled in the study. All cases were treated with 2 courses of glucocorticoid therapy before surgery. Tumor response was assessed by computed tomography (CT) scan 1 week after the steroid pulse therapy. Lymphocytes associated with thymoma were analyzed for their CD4/CD8 phenotype and glucocorticoid receptor (GR). TdT‐mediated dUTP‐biotin nick‐end labeling (TUNEL) staining was used to analyze the apoptotic lymphocytes and epithelial cells.

RESULTS

The overall response rate to the steroid pulse therapy was 47.1% (8 of 17). The reduction in tumor size was most prominent in type B1 thymomas; there were significant differences between type AB and type B1 thymomas (P = .0234) and type B1 and type B3 thymomas (P = .0068). The reduction in tumor size was accompanied with a marked reduction in the CD4+8+ double‐positive immature thymocytes that expressed higher levels of glucocorticoid receptor. Apoptotic changes were observed in both neoplastic epithelial cell and lymphocyte components after glucocorticoid therapy.

CONCLUSIONS

The efficiency of preoperative steroid pulse therapy in type B1 thymoma was most prominent, which is probably related to the specific effect on GR‐rich CD4+8+ double‐positive immature lymphocytes, which are abundant in this type of thymoma. Cancer 2006. © 2006 American Cancer Society.
Water Formation on Pt and Pt‐based Alloys: A Theoretical Description of a Catalytic Reaction
Authors: Jacob Timo , Goddard William A.
Published: April 2006

In the past, the modeling of catalytic processes was limited by the size and complexity of the systems involved. However, the enormous progress in both computer power and theoretical methods has made computational modeling a valuable tool in increasing our knowledge of catalytic reactions on the atomic scale. While complex reactions can be studied by dividing the overall reaction into a series of steps calculable by quantum mechanics, the combination with methods appropriate for larger time and length scales enables the gap between these regimes to be bridged. This provides a more realistic modeling of the experimental system and allows important environmental effects such as solvation to be taken into account. In this Minireview we describe some of the main theoretical methodologies that are used to study catalytic properties and reactions on surfaces. Using these methods, we study the seemingly simple reaction of water formation out of hydrogen and oxygen on Pt and Pt/Ni alloy catalysts. To provide a more realistic description we also discuss the interesting effects determined by hydrating the system or using alloy nanoparticles rather than extended surfaces.
Hypomagnesemia, oxidative stress, inflammation, and metabolic syndrome
Authors: Guerrero‐Romero Fernando , Rodríguez‐Morán Martha
Published: April 2006

Background

Although hypomagnesemia, oxidative stress, and inflammation are involved in the pathogenesis of cardiovascular diseases, there is not a previous description concerning their potential interaction; thus, the aim of this study was to examine the relationship between metabolic syndrome (MetS), hypomagnesemia, inflammation, and oxidative stress.

Methods

Case‐control design study. Incident cases of MetS (84 women and 63 men) were compared with healthy control subjects (163 women and 131 men) matched by age and gender. MetS was diagnosed according to the Adult Treatment Panel III (ATP III) criterion. Oxidative stress was defined by serum malondialdehyde concentration (MDA) ≥50 mg/dL, low‐grade chronic inflammation by C‐reactive protein (CRP) serum levels ≥3 mg/L, and hypomagnesemia by serum magnesium concentrations ≤1.8 mg/dL.

Results

Multivariate analysis adjusted by age, sex, body mass index, waist‐to‐hip ratio, and total adiposity showed a strong association between MetS and hypomagnesemia (OR 1.9; 95% CI 1.3–7.1), inflammation (OR 1.7; 95% CI 1.4–8.4), and oxidative stress (OR 1.4; 95% CI 0.9–12.6). Additional adjustment by CRP levels showed that MetS remained associated to hypomagnesemia (OR 1.4; 95% CI 1.1–5.9) but not to oxidative stress (OR 1.1; 95% CI 0.9–5.9), and adjusted by MDA levels, MetS remained strongly associated to hypomagnesemia (1.6; CI 95% 1.1–7.4), but not to inflammation (OR 1.05; 95% CI 0.97–14.2). Adjusted by serum magnesium levels, inflammation (OR 1.2; 95% CI 1.1–9.1) and oxidative stress (OR 1.1; 95% CI 1.1–9.7) were slightly associated to MetS.

Conclusions

The interaction of inflammation and oxidative stress is related and increases the risk for MetS, whereas serum magnesium levels and MetS are independently associated. Copyright © 2006 John Wiley & Sons, Ltd.
Ti/TiO2 Electrode Preparation Using Laser Anneal and Its Application to Determination of Chemical Oxygen Demand
Authors: Li Jiaqing , Zheng Lei , Li Luoping , Shi Guoyue , Xian Yuezhong , Jin Litong
Published: April 2006

A method for Ti/TiO2 photoelectrode preparation using laser calcination instead of oven calcination process was introduced. The prepared TiO2 film was investigated by X‐ray diffraction (XRD), electrochemical impedance spectroscopy (EIS) and amperometry, and it was found that the prepared electrode mainly consisted of anatase TiO2 nanoparticles on its surface and exhibited a superior photocatalytic activity. The electrode was employed as a sensor to measure chemical oxygen demand (COD) of the wastewater. The measuring principle was based on the photocurrent responses of the electrode which were proportional to the COD values. Under the optimized experimental conditions, the linear range was 50–2000 mg L−1, and the detection limit was 16 mg L−1 (S/N=3). This method was characterized by short analysis time, simplicity, low environmental impact and long lifetime of the sensor. Additionally, the COD values obtained from the proposed and conventional methods agreed well as demonstrated by the high significant correlation between the two sets of COD values (R=0.9895, n=25).
Variability in sediment supply, transfer and deposition in an upland torrent system: Iron Crag, northern England
Authors: Johnson R. M. , Warburton J.
Published: April 2006

Research into torrent erosion has focused on bedload transport dynamics, debris flow propagation during flood events, and fan sedimentation. Studies have frequently been biased towards specific events and have not considered sediment delivery in the catchment as a whole. The aim of this study is to examine spatial variations and process controls on sediment transfer in an upland torrent system (hillslopes, channel and fan).

The study site is Iron Crag, a small torrent system (catchment area 2·4 ha) situated in the northern Lake District, UK. Particle size analysis of hillslope sediments trapped during transport suggests sediment calibre is controlled primarily by sediment source. Freeze–thaw and rainfall processes impart a weak but recognizable size sorting signature on the trapped sediments. However, these variations are less significant in determining sediment supply to the basal fan, than those operating in the channel system. Channel sediment movement is strongly influenced by storm events, the type of flow process (debris flow or fluvial flow), the sediment characteristics, and the local channel topography. The importance of the channel–fan coupling is clearly demonstrated in that more than 90 per cent of fan sedimentation is derived from channel sediment sources. Copyright © 2006 John Wiley & Sons, Ltd.
Cirque development in a steadily uplifting range: rates of erosion and long‐term morphometric change in alpine cirques in the Ben Ohau Range, New Zealand
Authors: Brook Martin S. , Kirkbride Martin P. , Brock Ben W.
Published: April 2006

The intractable obstacle to understanding cirque evolution has been the lack of an independent timescale against which to measure morphometric change. By using known rates of transport and uplift of the Southern Alps, combined with the oxygen isotope record contained in marine sediments, it is possible to estimate the duration of glacial occupancy of cirques in the Ben Ohau Range. The pattern is one of very limited glaciation of the southern range, with glacial occupancy increasing northwards. Map‐based measurement of 18 morphometric properties in each of 92 cirques reveals systematic northward trends in cirque size, form and altitude, which are explained as reflections of increasing cirque ‘age’ (i.e. length of glacial occupancy). Thus, the validity of space–time substitution is demonstrated rather than assumed, and morphometric trends define evolutionary stages of cirque development. For cirques with up to c. 750 ka occupancy, rates of downcutting average 0·29 mma−1 and headwall retreat 0·44 mm a−1. There is no indication of attainment of an equilibrium form within this time: both cirque size and form continue to evolve throughout, with few parameters showing a convergence of value with cirque ‘age’. Some morphometric parameters perform much better than others: the k coefficient of the long‐profile descriptor is the most powerful predictor of cirque ‘age’, and simple measures correlate better than derived measures (e.g. ratios of dimensions). The trends identified concur with some previously published ideas, but for the first time provide empirically quantified rates of change at an appropriate timescale. Copyright © 2006 John Wiley & Sons, Ltd.
Scale relationships in hillslope runoff and erosion
Authors: Parsons Anthony J. , Brazier Richard E. , Wainwright John , Powell D. Mark
Published: April 2006

Eight runoff plots, located within a small catchment within the Walnut Gulch Experimental Watershed, southern Arizona, were constructed to test the argument that sediment yield (kg m−2) decreases as plot length increases. The plots ranged in length from 2 m to 27·78 m. Runoff and sediment loss from these plots were obtained for ten natural storm events. The pattern of sediment yield from these plots conforms to the case in which sediment yield first increases as plot length increases, but then subsequently decreases. Data from the present experiment indicate that maximum sediment yield would occur from a plot 7 m long. Analysis of both runoff and sediment yield from the plots indicates that the relationship of sediment yield to plot length derives both from the limited travel distance of individual entrained particles and from a decline in runoff coefficient as plot length increases. Particle‐size analysis of eroded sediment confirms the role of travel distance in controlling sediment yield. Whether in response to the finite travel distance of entrained particles or the relationship of runoff coefficient to plot length, the experiment clearly demonstrates that the erosion rates for hillslopes and catchments cannot be simply extrapolated from plot measurements, and that alternative methods for estimating large‐area erosion rates are required. Copyright © 2006 John Wiley & Sons, Ltd.
The influence of grazing on vegetation, soil properties and stream discharge in a small Dartmoor catchment, southwest England, UK
Authors: Meyles E. W. , Williams A. G. , Ternan J. L. , Anderson J. M. , Dowd J. F.
Published: April 2006

Intensive grazing has been responsible for environmental degradation of moorland landscapes over the last 50 years. Anecdotal evidence on Dartmoor, UK, for example, has suggested that it is particularly associated with a greater frequency of large floods, lower baseflow and a greater occurrence of erosion. A study was therefore conducted at Holne Moor, a small catchment on east Dartmoor, to investigate the impacts of grazing animals on hillslope hydrology and stream discharge. The vegetation in the study area ranged from heather (Calluna vulgaris), in areas with low grazing intensity, to short grass with occasional erosion scars visible associated with larger sheep numbers. The physical characteristics of the topsoil beneath heather species were very different compared with short grass. This was not due so much to the direct physical impact of grazing animals, but indirectly to the chemical and biological differences brought about by changes in vegetation response and soil structure. The experiment at Holne Moor indicated that soil water content on the hillslope was linked directly to the stream's rainfall–runoff response via the soil water pathways. In relatively dry conditions, the soil water content is mainly determined by local factors such as vegetation. In wet periods, non‐local influences such as slope and contributing area are more important. A soil water content threshold of around field capacity separated the two conditions. A comparison between soil physical properties and soil moisture under different vegetation types indicated that this ‘runoff’ threshold between dry and wet states is lower in heavily grazed areas. It is argued that more intense grazing causes conditions suited to the increased delivery of soil water to rapid flowpaths such as sheep tracks and other rapid routes which connect the source of this hillslope water to the contributing areas during large floods. Any alteration of vegetation and soil properties due to management causes a substantial increase in ‘active’ source areas and therefore discharge during large storm events even before any erosion occurs. Copyright © 2006 John Wiley & Sons, Ltd.
Gallager bounds on the performance of maximum‐likelihood decoded linear binary block codes in AWGN interference
Authors: Yousefi Shahram
Published: April 2006

Performance evaluation of maximum‐likelihood (ML) soft‐decision‐decoded binary block codes is usually carried out using bounding techniques. Many tight upper bounds on the error probability of binary codes are based on the so‐called Gallager's first bounding technique (GFBT). In this method, Gallager bisects the error probability to the joint probability of error and noise residing in a region ℜ (here referred to as the Gallager region) plus joint probability of error and noise residing in the complement of ℜ (also referred to as regions of many and few errors, respectively); where ℜ is a volume around the transmitted codeword. In this tutorial review, a comprehensive study of a number of upper bounds on the error probability of ML decoding of binary codes based on GFBT is provided. For some bounds, their applicability to other schemes is also pointed out and argued. We also provide an overview of bounds based on Gallager's second bounding technique (GSBT) and discuss some of their relations and interconnections. Copyright © 2006 AEIT
Comparative examination of the essential oils of Anthemis ruthenica and A. arvensis wild‐growing in Serbia
Authors: Vujisić Lj. , Vučković I. , Tešević V. , Đoković D. , Ristić M. S. , Janaćković P. , Milosavljević S.
Published: April 2006

The essential oils from the aerial parts of Anthemis ruthenica and Anthemis arvensis, wild‐growing in Serbia, obtained by hydrodistillation were analyzed using GC and GC/MS. A total of 75 and 81 components were identified in A. ruthenica and A. arvensis, respectively. The major constituents of A. ruthenica oil were β‐pinene (3.6%), 1,8‐cineol (6.8%), 4‐terpineol (6.2%), α‐terpineol (3.6%), isophyllocladene (5.4%) and palmitic acid (9.9%). The oil of A. arvensis showed a high content of non‐terpenic compounds. The main components were palmitic acid (21.2%) and linoleic acid (6.5%). The most abundant terpenic compounds in the oil of A. arvensis were pinocarvone (5.4%) and isospathulenol (4.6%). Copyright © 2006 John Wiley & Sons, Ltd.
Diminishing the social network in organizations: does there need to be such a phenomenon as ‘survivor syndrome’ after downsizing?
Authors: Travaglione Anthony , Cross Bernadette
Published: April 2006

Many management fads have been shown to be detrimental to the well‐being of employees as well as to the long‐term competitiveness of organizations. Downsizing has been recognized as belonging to this category and research has begun to clarify what is now commonly known as ‘survivor syndrome’, the negative attitudes and behaviours of those that survive retrenchment. However, recent evidence shows that ‘survivor syndrome’ does not actually exist in all downsizing situations.

By closely examining the specific conditions under which the effects of downsizing are lessened, this study contributes to the development of effective interventions for dealing with organizational change. Using the data from a longitudinal survey, this paper investigates the impact of downsizing on survivor attitudes of affective and continuance commitment, general and specific job satisfaction, perceived organizational support, and the behaviours of performance, effort, turnover intention and absenteeism.

While analyses reveal evidence of decline in some of the variables after the downsizing, a more important finding was support for the counter‐argument that a syndrome does not actually exist. Four of the variables were not significantly affected by downsizing. The implication for management is that effective management of a downsizing programme can decrease the likelihood of a syndrome permeating an organization.

Copyright © 2006 John Wiley & Sons, Ltd.
Hot air treatment decreases chlorophyll catabolism during postharvest senescence of broccoli (Brassica oleracea L. var. italica) heads
Authors: Costa Maria L , Civello Pedro M , Chaves Alicia R , Martínez Gustavo A
Published: April 2006

A hot air treatment was applied to broccoli (Brassica oleracea L. var. italica) florets and its effect on chlorophyll catabolism during postharvest senescence was analyzed. Florets were treated at 48 °C for 3 h and then placed in darkness at 20 °C. During storage, the yellowing of florets occurred simultaneously with a decrease in chlorophylls and an increase in pheophytins. Heat treatment delayed the appearance of yellowing by 2–3 days and a similar extension of shelf‐life could be inferred. Also, the treatment delayed the onset of chlorophyll catabolism and slowed both the rate of chlorophyll a degradation and pheophytin accumulation. No effect on chlorophyll b degradation was found. Chlorophyllase and Mg‐dechelatase activities increased from the first day of storage in untreated florets, whereas peroxidase‐linked chlorophyll bleaching activity increased from day 3. In heat‐treated florets, chlorophyllase activity did not increase until day 2 and then increased at lower rate than in controls. Mg‐dechelatase and peroxidase‐linked chlorophyll bleaching activities were similar in treated and control florets during the first 2 days of storage, but thereafter the activity of both enzymes was lower in heat‐treated samples. In conclusion, a treatment at 48 °C for 3 h delayed chlorophyll a catabolism in broccoli during postharvest senescence and decreased the activities of chlorophyllase, Mg‐dechelatase and peroxidase, three of the enzymes probably involved in chlorophyll degradation in plants. Copyright © 2006 Society of Chemical Industry
Total and ileal digestible tryptophan contents of feedstuffs for broiler chickens
Authors: Ravindran Ganesharanee , Ravindran Velmurugu , Bryden Wayne L
Published: April 2006

Reliable values of total and digestible tryptophan in components of feed formulation matrices are needed because tryptophan is often the third limiting amino acid in practical poultry diets. However, tryptophan is oxidatively destroyed during acid hydrolysis in routine amino acid analysis and its determination requires a separate analytical procedure. The variability in contents and apparent ileal digestibility for 6‐week‐old broiler chickens of tryptophan in 74 samples representing 24 feedstuffs are presented in this paper. The average ileal tryptophan digestibility coefficient in wheat was 0.83, in sorghum and triticale 0.75, maize 0.71, soybean meal 0.84, sunflower meal 0.81, canola meal 0.78 and cottonseed meal 0.75. Among the grain legumes, tryptophan in lupins was better digested than that in chickpeas, fababeans and field peas. Among the animal protein meals, the tryptophan digestibility coefficients in fish meal (0.77) and blood meal (0.84) were substantially higher than those in meat meal (0.62), meat‐and‐bone meal (0.63) and feather meal (0.52). Marked variations in tryptophan digestibility were also observed among samples of fish meal, meat‐and‐bone meal and meat meal, highlighting significant batch‐to‐batch differences. For most feedstuffs, considerable variability was observed in the tryptophan concentrations, but such variations were not reflected in digestibility coefficients. Copyright © 2006 Society of Chemical Industry
Modelling and parameter comparison of equivalent circuits on the basis of impedance measurements of stainless steels
Authors: Slemnik M.
Published: April 2006

In our former work [1] we have discussed the impedance of differently heat treated steels X20Cr13 in 0.1 M H2SO4, undergoing an active passive transition. Impedance spectra were interpreted in terms of a model by Armstrong [2, 3], describing the electrochemical reaction at interfaces with adsorbed intermediates. The present work was performed in order to study this phenomenon in more detail, with computer simulations of a new created and more convenient equivalent circuit in comparison with the former model. Computer simulations of equivalent circuits were also made in the region of passivity which was also continuation of our earlier work [4]. In this sense the entire study for these steels was completed by collating distinctive parameter values, demonstrating electrochemical characteristics of steel X20Cr13, undergoing different heat treatments in the active‐passive and passive region.
Study of the behavior of an organic coating applied on the storage reservoirs of oil in a medium of 3% NaCl solution and in marine environment
Authors: Hammouda N. , Boudinar Y. , Touiker M. , Belmokre K.
Published: April 2006

The paints are used extensively in various fields, especially for the protection of the oil installations such as the storage reservoirs of crude oil. Reducing possession cost and applying the new hygiene and security standards imply the necessity to deepen the knowledge of the physico‐chemical processes of ageing coatings in the first stage and their impact on the corrosion of the substrate. The tests have been carried out on a primer, and on painted steel plates completely immersed in a 3% NaCl solution. The survey of the water absorption and the kinetics deterioration of the paints have been achieved especially by means of electrochemical impedance spectroscopy under the test of salt spray. The barrier weakness of the primer paint, due to the existence of two capacitive loops observed on the Nyquist's diagrams has been put in evidence. While the study of the resistance of the complete system by the test accelerated in the salt spray shows that the system of painting presents a good resistance up to 196 hours, which is equivalent to 8 years of exposure.
Effect of Al2O3 and TiO2 nanoparticles and APP on thermal stability and flame retardance of PMMA
Authors: Laachachi A. , Cochez M. , Leroy E. , Gaudon P. , Ferriol M. , Lopez Cuesta J. M.
Published: April 2006

Ammonium polyphosphate (APP)‐based additives and Al2O3 and TiO2 nanoparticles have been incorporated separately or combined at a 15 wt% global percentage in poly(methyl methacrylate) (PMMA). APP–based additive containing melamine phosphate has led to an intumescent behavior during cone calorimeter tests, whereas thermal stability was particularly improved by the use of the oxide nanoparticles. APP with melamine phosphate and Al2O3 combination allowed significant synergism on flame retardance to be achieved, owing to the catalytic action of alumina well‐dispersed nanoparticles, which modified the decomposition pathway of PMMA and the formation of a charred and ceramized structure. Aggregation processes in the case of TiO2 seemed to limit the catalytic action of the surface and did not allow synergism for flame retardance to be observed. Copyright © 2006 John Wiley & Sons, Ltd.