bluuebunny/crossref_metadata_2025 huggingface dataset:
Deliberate self‐harm in people aged 60 years and over: characteristics and outcome of a 20‐year cohort
Authors: Hawton Keith , Harriss Louise
Published: April 2006

Background

Little information is available about older deliberate self‐harm (DSH) patients and their outcome.

Methods

This study is a prospective investigation and follow‐up of 730 consecutive patients (459 females and 271 males) aged 60 years and over who presented to a general hospital following DSH over a 20‐year period, 1978–1997. Outcome has been examined in terms of repetition of DSH, and deaths by the end of 2000 identified through official death registers.

Results

DSH involved self‐poisoning in 88.6% of cases, 49.3% of the overdoses including paracetamol (acetaminophen), 24.0% minor tranquillizers, and 15.9% antidepressants. Nearly three‐quarters of episodes involved high suicidal intent. Common problems preceding DSH were physical illness (46.1%), social isolation (33.5%), relationship problems with family (29.4%) or partner (25.9%), and bereavement or loss (16.7%). Repetition of DSH occurred in 15.3% of cases, 8.2% in the first year following DSH. By the end of 2000, 432/661 (65.4%) of traced patients had died. There were 30 suicides and open verdicts, which were 49 times and 33 times more frequent respectively than expected from general population death rates. Prior DSH before initial presentation was the main risk factor for suicide, with some evidence of high suicide intent being another factor. There were also excess deaths due to several types of physical disorder.

Conclusions

DSH in older people is closely related to suicide, both in terms of suicidal intent and risk of eventual suicide, especially when DSH is repeated. The range of problems experienced by older DSH patients requires extensive and multidisciplinary clinical interventions. Copyright © 2006 John Wiley & Sons, Ltd.
High salt diets dose‐dependently promote gastric chemical carcinogenesis in Helicobacter pylori‐infected Mongolian gerbils associated with a shift in mucin production from glandular to surface mucous cells
Authors: Kato Sosuke , Tsukamoto Tetsuya , Mizoshita Tsutomu , Tanaka Harunari , Kumagai Toshiko , Ota Hiroyoshi , Katsuyama Tsutomu , Asaka Masahiro , Tatematsu Masae
Published: April 2006

Intake of salt and salty food is known as a risk factor for gastric carcinogenesis. To examine the dose‐dependence and the mechanisms underlying enhancing effects, Mongolian gerbils were treated with N‐methyl‐N‐nitrosourea (MNU), Helicobacter pylori and food containing various concentrations of salt, and were sacrificed after 50 weeks. Among gerbils treated with MNU and H. pylori, the incidences of glandular stomach cancers were 15% in the normal diet group and 33%, 36% and 63% in the 2.5%, 5% and 10% NaCl diet groups, showing dose‐dependent increase (p < 0.01). Intermittent intragastric injection of saturated NaCl solution, in contrast, did not promote gastric carcinogenesis. In gerbils infected with H. pylori, a high salt diet was associated with elevation of anti‐H. pylori antibody titers, serum gastrin levels and inflammatory cell infiltration in a dose‐dependent fashion. Ten percent NaCl diet upregulated the amount of surface mucous cell mucin (p < 0.05), suitable for H. pylori colonization, despite no increment of MUC5AC mRNA, while H. pylori infection itself had an opposing effect, stimulating transcription of MUC6 and increasing the amount of gland mucous cell mucin (GMCM). High salt diet, in turn, decreased the amount of GMCM, which acts against H. pylori infection. In conclusion, the present study demonstrated dose‐dependent enhancing effects of salt in gastric chemical carcinogenesis in H. pylori‐infected Mongolian gerbils associated with alteration of the mucous microenvironment. Reduction of salt intake could thus be one of the most important chemopreventive methods for human gastric carcinogenesis. © 2006 Wiley‐Liss, Inc.
In vitro and in vivo evaluation of WK‐X‐34, a novel inhibitor of P‐glycoprotein and BCRP, using radio imaging techniques
Authors: Jekerle Veronika , Klinkhammer Werner , Scollard Deborah A. , Breitbach Kerstin , Reilly Raymond M. , Piquette‐Miller Micheline , Wiese Michael
Published: April 2006

Overexpression of the multidrug resistance proteins P‐glycoprotein (Pgp) and breast cancer resistance protein (BCRP) results in treatment failure of many malignancies including ovarian cancer. Dual inhibition of Pgp and BCRP may restore the sensitivity of resistant cells to anticancer drugs. We report the synthesis and characterization of a novel anthranilic‐acid based Pgp and BCRP modulator, WK‐X‐34. In vitro inhibition of Pgp activity was evaluated using 99mTc‐Sestamibi and daunorubicin accumulation in Pgp overexpressing human ovarian cancer cells (A2780/Adr) and its sensitive counterpart (A2780/wt). Interaction with BCRP was examined with a mitoxantrone‐efflux assay in BCRP‐overexpressing MCF7/mx cells, with flow cytometry. Interactions with the multidrug resistance associated proteins (MRP) were evaluated in transfected MRP1, MRP2 and MRP3 cell lines, using a 5‐CFDA efflux assay. In vivo99mTc‐Sestamibi imaging of human ovarian cancer xenografts was used to evaluate the in vivo efficacy of WK‐X‐34 in mice. Daunorubicin accumulation in A2780/Adr cells was inhibited by WK‐X‐34 at nanomolar concentrations (IC50: 82.1 ± 6 nM). WK‐X‐34 inhibited mitoxantrone accumulation in BCRP‐overexpressing cells at micromolar concentrations (IC50 = 26.5 ± 4.6 μM), whereas WK‐X‐34 did not significantly alter 5‐CFDA accumulation in MRP transfected cells. In vivo, uptake of 99mTc‐Sestamibi was significantly increased in A2780/Adr xenograft tumors, brain and intestine (AUCs0‐4h 136%, 147% and 138%; p < 0.05) in mice dosed with WK‐X‐34 (20 mg/kg i.p.). WK‐X‐34 selectively modulates Pgp and BCRP in vitro and in vivo in multidrug resistant ovarian cancer cells, and thus may have potential utility in the treatment of multidrug resistant tumors. © 2006 Wiley‐Liss, Inc.
Clinically tolerable concentrations of arsenic trioxide induce p53‐independent cell death and repress NF‐κB activation in Ewing sarcoma cells
Authors: Mathieu Julie , Besançon Françoise
Published: April 2006

Ewing sarcoma (ES), a highly malignant pediatric tumor, is consistently associated with translocations that fuse the EWS gene with a member of the ETS family gene, most commonly FLI‐1. Despite significant advances with multiagent chemotherapy, surgery and radiotherapy, about 40% of ES patients still die from the disease. It is therefore necessary to explore novel agents for possible treatment of this tumor. Here the authors investigated the sensitivity of ES cells to clinically tolerable concentrations of arsenic trioxide (As2O3), a compound known to induce differentiation and apoptosis of other types of malignant cells. The authors report that As2O3 uniformly induced death of 6 ES‐derived cell lines irrespective of their p53 status. As2O3 resulted in an apoptotic phenotype which was inhibited by the broad‐spectrum caspase inhibitor ZVAD‐fmk. These effects correlated with prolonged c‐jun N‐terminal kinase activation, which is a signal for apoptosis in ES cells. As2O3 also decreased basal and cytokine‐induced NF‐κB activity. Since the authors previously demonstrated that NF‐κB exerts an antiapoptotic action in ES cells, As2O3 treatment may also result in a sensitization of these cells to other drugs used in combination therapy. These effects, combined with its antiangiogenic action, define As2O3 as a good candidate for future protocols to improve treatments of Ewing sarcomas, irrespective of the p53 status of the tumor. © 2006 Wiley‐Liss, Inc.
ARLTS1 variants and melanoma risk
Authors: Frank Bernd , Meyer Peter , Boettger Melanie Barbara , Hemminki Kari , Stapelmann Henrike , Gast Andreas , Schmitt Christina , Kumar Rajiv , Sergi Consolato , Burwinkel Barbara
Published: April 2006

Variants in the tumor suppressor gene ARLTS1 (ADP‐ribosylation factor‐like tumor‐suppressor gene 1) have been shown to influence familial cancer risk. Both Cys148Arg and Trp149Stop were associated with an increased risk of familial or high‐risk familial breast cancer, respectively. We studied the impact of these gene variants on melanoma risk, investigating 351 melanoma patients and 804 control subjects. While ARLTS1 Trp149Stop did not influence melanoma risk (OR = 0.83, 95% CI = 0.37–1.88, p = 0.65), Cys148Arg revealed a statistically significant association with an increased risk for heterozygous carriers (OR = 1.43, 95% CI = 1.05–1.95, p = 0.02). An additional risk enhancement, though statistically non‐significant, was observed in individuals with multiple melanomas (OR = 2.33, 95% CI = 0.87–6.26, p = 0.08). © 2006 Wiley‐Liss, Inc.
Dietary folate is associated with p16INK4A methylation in head and neck squamous cell carcinoma
Authors: Kraunz Kim S. , Hsiung Debra , McClean Michael D. , Liu Mei , Osanyingbemi Joyce , Nelson Heather H. , Kelsey Karl T.
Published: April 2006

Inactivation of the p16INK4A (CDKN2A) gene in the Rb pathway is among the most common somatic alterations observed in tobacco‐related solid tumors, including head and neck squamous cell carcinoma (HNSCC). In addition, a low folate diet is an important risk factor for HNSCC. Decreased dietary folate in an animal model of hepatocellular carcinoma has been associated with the induction of epigenetic silencing of the p16INK4A gene. In an ongoing population‐based study of HNSCC, we sought to extend this observation to human disease testing the hypothesis that p16INK4A methylation is associated with decreased dietary folate. We also investigated the association of methylation silencing with functional polymorphisms in the folate metabolism enzyme methylene tetrahydrofolate reductase (MTHFR). In 169 HNSCCs, the odds ratio for p16INK4A methylation among those with low dietary folate intake was 2.3 (95% CI = 1.1–4.8) when compared with those with high folate intake. Furthermore, this increased risk for epigenetic silencing at p16INK4A was modified by the MTHFR alleles previously associated with diminished serum folate levels. Hence, in HNSCC low dietary intake of folate is associated with p16INK4A methylation, and this relationship is modified by the MTHFR genotype. Our data provides important evidence for a mechanism of action of folate deficiency in cancer. © 2006 Wiley‐Liss, Inc.
2‐Deoxy‐L‐ribose inhibits the invasion of thymidine phosphorylase‐overexpressing tumors by suppressing matrix metalloproteinase‐9
Authors: Nakajima Yuichi , Haraguchi Misako , Furukawa Tatsuhiko , Yamamoto Masatatsu , Nakanishi Hayao , Tatematsu Masae , Akiyama Shin‐ichi
Published: April 2006

Thymidine phosphorylase (TP), an enzyme involved in pyrimidine metabolism, is identical with an angiogenic factor, platelet‐derived endothelial cell growth factor. 2‐Deoxy‐D‐ribose (D‐dRib), the degradation product of thymidine generated by TP activity, has been suggested to be a downstream mediator of TP function. 2‐Deoxy‐L‐ribose (L‐dRib), a stereoisomer of D‐dRib, inhibited the promotion of angiogenesis, tumor growth and metastasis by TP. In our study, we have shown that nude mice inoculated with TP‐overexpressing KB/TP cells had shorter survival times than those injected with control KB/CV cells. KB/TP tumors were also more highly invasive than KB/CV tumors in mice. The expression levels of matrix metalloproteinase (MMP)‐9 in KB/TP tumors were significantly higher than those in KB/CV tumors. L‐dRib and a TP inhibitior, TPI, extended the survival period of KB/TP tumor‐bearing mice. L‐dRib also reduced MMP‐9 mRNA levels in KB/TP tumors. Furthermore, L‐dRib suppressed the mRNA level of MMP‐9 in cultured KB/TP cells, and the invasive activity of the cells. L‐dRib may be useful for the suppression of invasion of TP‐expressing tumor cells. © 2006 Wiley‐Liss, Inc.
Body weight and postmenopausal breast cancer risk defined by estrogen and progesterone receptor status among Swedish women: A prospective cohort study
Authors: Suzuki Reiko , Rylander‐Rudqvist Tove , Ye Weimin , Saji Shigehira , Wolk Alicja
Published: April 2006

Although obesity is one of the established risk factors for postmenopausal breast cancer, it is not clear whether this positive association differs across estrogen receptor (ER) and progesterone receptor (PR) status of breast tumors. We evaluated the association between body weight and ER/PR defined breast cancer risk stratified by postmenopausal hormone (PMH) use and a family history of breast cancer in the population‐based Swedish Mammography Screening Cohort comprising 51,823 postmenopausal women. Relative body weight was measured by body mass index (kg/m2) based on self‐reported weight and height collected in 1987 and 1997. Relative risks (RRs) were estimated by hazard ratios derived from Cox proportional hazards regression models. During an average of 8.3‐year follow‐up, 1,188 invasive breast cancer cases with known ER and PR status were diagnosed. When comparing to normal weight group, we observed a positive association between obesity and risk for the development of ER+ PR+ tumors (RR = 1.67, 95% CI = 1.34–2.07) and an inverse association for the development of all PR− tumors (RR = 0.68, 95% CI = 0.47–0.98). Statistically significant heterogeneity was observed in the RRs between ER+ PR+ tumors and all PR− tumors (pheterogeneity < 0.0001). The positive association of obesity with the development of ER+ PR+ tumors was confined to never‐users of PMHs (RR = 1.90 (CI 95%:1.38–2.61)) and to those without a family history of breast cancer (RR = 1.82 (CI 95%:1.45–2.29)). Our results support the hypothesis that excess endogenous estrogen due to obesity contributes to an increased risk of ER+ PR+ postmenopausal breast cancer. © 2006 Wiley‐Liss, Inc.
Oral administration of human papillomavirus type 16 E7 displayed on Lactobacillus casei induces E7‐specific antitumor effects in C57/BL6 mice
Authors: Poo Haryoung , Pyo Hyun‐Mi , Lee Tae‐Young , Yoon Sun‐Woo , Lee Jong‐Soo , Kim Chul‐Joong , Sung Moon‐Hee , Lee Seung‐Hoon
Published: April 2006

The mounting of a specific immune response against the human papillomavirus type 16 E7 protein (HPV16 E7) is important for eradication of HPV16 E7‐expressing cancer cells from the cervical mucosa. To induce a mucosal immune response by oral delivery of the E7 antigen, we expressed the HPV16 E7 antigen on the surface of Lactobacillus casei by employing a novel display system in which the poly‐γ‐glutamic acid (γ‐PGA) synthetase complex A (PgsA) from Bacillus subtilis (chungkookjang) was used as an anchoring motif. After surface expression of the HPV16 E7 protein was confirmed by Western blot, flow cytometry and immunofluorescence microscopy, mice were orally inoculated with L. casei‐PgsA‐E7. E7‐specific serum IgG and mucosal IgA productions were enhanced after oral administration and significantly enhanced after boosting. Systemic and local cellular immunities were significantly increased after boosting, as shown by increased counts of lymphocytes (SI = 9.7 ± 1.8) and IFN‐γ secreting cells [510 ± 86 spot‐forming cells/106cells] among splenocytes and increased IFN‐γ in supernatants of vaginal lymphocytes. Furthermore, in an E7‐based mouse tumor model, animals receiving orally administered L. casei‐PgsA‐E7 showed reduced tumor size and increased survival rate versus mice receiving control (L. casei‐PgsA) immunization. These results collectively indicate that the oral administration of E7 displayed on lactobacillus induces cellular immunity and antitumor effects in mice. © 2006 Wiley‐Liss, Inc.
Human fibroblasts undergo oxidative stress‐induced apoptosis without internucleosomal DNA fragmentation
Authors: Formichi P. , Radi E. , Battisti C. , Tarquini E. , Leonini A. , Di Stefano A. , Federico A.
Published: April 2006

In order to evaluate the reliability of fibroblasts as a cell model for studying apoptosis, we tested the response of normal human fibroblasts to the oxidative stress inducers H2O2 and 2‐deoxy‐D‐ribose (dRib). Our results showed that fibroblasts treated with dRib and H2O2 are induced to undergo apoptosis as demonstrated by reduction in total cell number, chromatin condensation, phosphatidylserine (PS) exposure, activation of caspase‐3 and 7, changes in mitochondrial membrane potential and increase in the number of terminal deoxynucleotidyl transferase‐mediated dUTP nick end‐labeling (TUNEL)‐positive nuclei. However we only found a slight increase in the percentage of cells in the sub‐G1 region evaluated by flow cytometry, and we did not observe DNA fragmentation by agarose gel electrophoresis. Early in apoptosis, DNA cleavage generates high molecular weight (HMW) fragments which can be detected by TUNEL assay; successively followed by a pronounced DNA brake down into low molecular weight (LMW) fragments, detected as a “DNA ladder” by conventional agarose gel electrophoresis and as an hypodiploid peak by propidium iodide (PI) flow cytometry assay. Our results thus suggest that only HMW fragmentation occurs in fibroblasts exposed to dRib or H2O2 and the lack of internucleosomal DNA fragmentation may depend on the peculiar characteristics of human fibroblasts themselves, irrespective of the apoptotic stimulus used. The existence of distinct events leading to cell death in different cell types makes it necessary to use a combination of strategies and techniques to evaluate the occurrence of apoptosis. J. Cell. Physiol. 208: 289–297, 2006. © 2006 Wiley‐Liss, Inc.
Ionizing radiation enhances adenoviral vector expressing mda‐7/IL‐24‐mediated apoptosis in human ovarian cancer
Authors: Emdad Luni , Sarkar Devanand , Lebedeva Irina V. , Su Zao‐zhong , Gupta Pankaj , Mahasreshti Parameshwar J. , Dent Paul , Curiel David T. , Fisher Paul B.
Published: April 2006

Ovarian cancer is the fifth most common cause of cancer‐related death in women. Current interventional approaches, including debulking surgery, chemotherapy, and/or radiation have proven minimally effective in preventing the recurrence and/or mortality associated with this malignancy. Subtraction hybridization applied to terminally differentiating human melanoma cells identified melanoma differentiation associated gene‐7/interleukin‐24 (mda‐7/IL‐24), whose unique properties include the ability to selectively induce growth suppression, apoptosis, and radiosensitization in diverse cancer cells, without causing any harmful effects in normal cells. Previously, it has been shown that adenovirus‐mediated mda‐7/IL‐24 therapy (Ad.mda‐7) induces apoptosis in ovarian cancer cells, however, the apoptosis induction was relatively low. We now document that apoptosis can be enhanced by treating ovarian cancer cells with ionizing radiation (IR) in combination with Ad.mda‐7. Additionally, we demonstrate that mda‐7/IL‐24 gene delivery, under the control of a minimal promoter region of progression elevated gene‐3 (PEG‐3), which functions selectively in diverse cancer cells with minimal activity in normal cells, displays a selective radiosensitization effect in ovarian cancer cells. The present studies support the use of IR in combination with mda‐7/IL‐24 as a means of augmenting the therapeutic benefit of this gene in ovarian cancer, particularly in the context of tumors displaying resistance to radiation therapy. J. Cell. Physiol. 208: 298–306, 2006. © 2006 Wiley‐Liss, Inc.
A20 inhibits oxidized low‐density lipoprotein‐induced apoptosis through negative Fas/Fas ligand‐dependent activation of caspase‐8 and mitochondrial pathways in murine RAW264.7 macrophages
Authors: Li Hong‐Liang , Wang Ai‐Bing , Zhang Ran , Wei Yu‐Sheng , Chen Hou‐Zao , She Zhi‐Gang , Huang Yue , Liu De‐Pei , Liang Chih‐Chuan
Published: April 2006

A20 was originally characterized as a TNF‐inducible gene in human umbilical vein endothelial cells. As an NF‐κB target gene, A20 is also induced in many other cell types by a wide range of stimuli. Expression of A20 has been shown to protect from TNF‐induced apoptosis and also functions via a negative‐feedback loop to block NF‐κB activation induced by TNF and other stimuli. To date, there are no reports on whether A20 can protect OxLDL‐induced apoptosis in macrophages. For the first time we report that A20 expression blocks OxLDL‐mediated cell toxicity and apoptosis. OxLDL induced the expression of Fas and FasL, and the subsequent caspase‐8 cleavage and treatment with a neutralizing ZB4 anti‐Fas antibody blocked apoptosis induced by OxLDL. Expression of dominant negative FADD efficiently prevented OxLDL‐induced apoptosis and caspase‐8 activation. A20 expression significantly attenuated the increased expression of Fas and FasL, and Fas‐mediated apoptosis. These findings suggest that A20‐mediated protection from OxLDL may occur at the level of Fas/FADD‐caspase‐8 and be FasL dependent. Treatment of RAW264.7 cells with OxLDL induces a series of time‐dependent events, including the release of cytochrome c, Smac and Omi from the mitochondria to the cytosol, activation of caspase‐9, ‐6, ‐2, and ‐3, which are blocked by A20 expression. No cleaved form of Bid was detected, even treatment with OxLDL for 48 h. Expression of dominant negative FADD also efficiently prevented OxLDL‐induced the above apoptotic events. The release of cyto c, Smac and Omi from mitochondria to cytosol, activated by OxLDL treatment, and the activation of caspase‐9 may not be a downstream event of caspase‐8‐mediated Bid cleavage. Therefore, the protective effect of A20 on mitochondrial apoptotic pathway activated by OxLDL may be dependent on FADD. A20 expression reversed OxLDL‐mediated G0/G1 stage arrest by maintaining the expression of cyclin B1, cyclin D1, and cyclin E, and p21 and p73. Thus, A20 expression blocks OxLDL‐mediated apoptosis in murine RAW264.7 macrophages through disrupting Fas/FasL‐dependent activation of caspase‐8 and the mitochondria pathway. J. Cell. Physiol. 208: 307–318, 2006. © 2006 Wiley‐Liss, Inc.
Atom probe tomography characterization of solute segregation to dislocations
Authors: Miller Michael K.
Published: April 2006

The extent and level of solute segregation to individual dislocations may be quantified by atom probe tomography. The technique is best applied to materials with high dislocation densities, such as cold worked, mechanically alloyed, or neutron‐irradiated materials. Dislocations may be observed in field ion images by a change of the normal concentric atom terraces at crystallographic poles to spirals. Solute segregation is evident in field ion images by brightly imaging atoms near the core of the dislocation. Dislocations are evident in atom maps in the three‐dimensional atom probe by linear regions of enhanced solute concentration. The maximum separation envelope and tracer methods may be used to quantify the levels of solute at the dislocation at the subnanometer scale. Examples of interstitial and substitutional element segregation in a mechanically alloyed, oxide dispersion strengthened ferrite steel and phosphorus segregation to dislocations in neutron‐irradiated pressure vessel steels are presented. Microsc. Res. Tech. 69:359–365, 2006. Published 2006 Wiley‐Liss, Inc.
Scanning electron microscopy imaging of dislocations in bulk materials, using electron channeling contrast
Authors: Crimp Martin A.
Published: April 2006

The imaging and characterization of dislocations is commonly carried out by thin foil transmission electron microscopy (TEM) using diffraction contrast imaging. However, the thin foil approach is limited by difficult sample preparation, thin foil artifacts, relatively small viewable areas, and constraints on carrying out in situ studies. Electron channeling imaging of electron channeling contrast imaging (ECCI) offers an alternative approach for imaging crystalline defects, including dislocations. Because ECCI is carried out with field emission gun scanning electron microscope (FEG‐SEM) using bulk specimens, many of the limitations of TEM thin foil analysis are overcome. This paper outlines the development of electron channeling patterns and channeling imaging to the current state of the art. The experimental parameters and set up necessary to carry out routine channeling imaging are reviewed. A number of examples that illustrate some of the advantages of ECCI over thin foil TEM are presented along with a discussion of some of the limitations on carrying out channeling contrast analysis of defect structures. Microsc. Res. Tech. 69:374–381, 2006. © 2006 Wiley‐Liss, Inc.
Study of Organic Phase Mobility in Nanocomposite Organic‐Inorganic Coatings
Authors: Ceccorulli Giuseppina , Zini Elisa , Scandola Mariastella
Published: April 2006

Summary: Organic‐inorganic hybrids synthesized by a dual photopolymerization and condensation process from (i) two organic precursors, either poly(ethylene glycol) α,ω diacrylate ($\overline M _{\rm w}$ = 600) (PEGDA) or bisphenol‐A‐ethoxylate(15EO/phenol)‐dimethacrylate (BEMA), (ii) the organic‐inorganic bridging monomer (methacryloyl‐oxypropyl‐trimethoxysilane, (MEMO)) and (iii) the inorganic precursor tetraethoxysilane (TEOS) were investigated by differential scanning calorimetry (DSC) and dynamic mechanical spectroscopy (DMTA). It is found that progressive formation of the crosslinked network during the different steps of hybrid production results in changes of molecular mobility that show up in changes of the glass transition of the organic phase. While moving from the organic precursor to the final hybrid through the subsequent photopolymerization and condensation reactions, the transition is seen to broaden, decrease in intensity and shift to higher temperature. Excellent agreement of DSC and DMTA results is obtained. Dynamic mechanical analysis of the hybrids coated on PET film (coating thickness 10 and 40 µm) show an additional up‐shift of Tg, more marked in the case of the thinner hybrid coating. This result is attributed to molecular interactions at the substrate‐coating interface that locally hinder molecular mobility. The consequent increase of Tg is more evident when the coating layer is thin. The results show the potential of the DMTA technique in coating‐polymer substrate adhesion studies. Finally, the relaxation spectrum of the hybrids is sensitive to humidity absorbed from the environment and reversibly changes in absorption‐desorption cycles.

DMTA loss spectrum of‘free’ PEGDA‐based hybrid film, PET film with thick coating and PET film with thin coating.

magnified image

DMTA loss spectrum of‘free’ PEGDA‐based hybrid film, PET film with thick coating and PET film with thin coating.
Styrene/Maleic Anhydride Macro‐RAFT‐Mediated Encapsulation
Authors: Klumperman Bert
Published: April 2006

Summary: Luo et al. have published a method for the encapsulation of oil droplets by a polymer shell to form nanosized liquid‐filled particles. They use a water‐soluble styrene–maleic anhydride copolymer that carries a thiocarbonyl thio end‐group. This end‐group is able to induce reversible addition‐fragmentation chain transfer (RAFT)‐mediated polymerization, which leads to a miniemulsion polymerization‐like system. Here the polymerization is confined to the outer shell of a droplet/particle. Consequently, monomer is depleted from the centre of the particle, which leaves a liquid core surrounded by a polymer shell. The technique seems robust and opens up new pathways to nanostructured materials.

Morphology development in the miniemulsion polymerization of styrene mediated by an aminolyzed STY/MAnh macro‐RAFT agent (black chains: the aminolyzed STY/MAnh copolymer, black dots: thiocarbonyl thio moieties that mediate the polymerization, red chains: styrene homopolymer).

magnified image

Morphology development in the miniemulsion polymerization of styrene mediated by an aminolyzed STY/MAnh macro‐RAFT agent (black chains: the aminolyzed STY/MAnh copolymer, black dots: thiocarbonyl thio moieties that mediate the polymerization, red chains: styrene homopolymer).
Linking Polythiophene Chains Through Conjugated Bridges: A Way to Improve Charge Transport in Polymer Solar Cells
Authors: Zhou Erjun , Tan Zhan'ao , Yang Chunhe , Li Yongfang
Published: April 2006

Summary: A series of cross‐linked polythiophene derivatives (P1–4) are synthesized by adding different ratio (0, 2, 5, and 10%) of conjugated cross‐linker via a Stille coupling reaction. From P1–4, with the increase of the content of the conjugated bridges, the UV‐visible absorption peaks of the polymers were shifted towards blue and their electrochemical bandgap increased. The hole mobilities of P1–4 as determined from the SCLC model are 5.23 × 10−6, 1.28 × 10−4, 7.01 × 10−3, and 2.34 × 10−5 cm2 · V−1 · s−1, respectively. The PCEs of the polymer solar cells based on P1–4 are 0.37, 1.05, 1.26, and 0.78%, respectively. The improvement of PCE of the devices based on P2–4 compared with that of P1 may be due to the increase of hole mobility.

Molecular structure of the polythiophene derivatives (P1–4).

magnified image

Molecular structure of the polythiophene derivatives (P1–4).
Study of Complex Organic Binding Media Systems on Artworks Applying GC‐MS Analysis: Selected Examples from the Kunsthistorisches Museum, Vienna
Authors: Pitthard Vaclav , Griesser Martina , Stanek Sabine , Bayerova Tatjana
Published: April 2006

Within the Kunsthistorisches Museum (KHM), Vienna, three off‐line GC‐MS analytical procedures for the identification of natural organic media have been refined, tested, and validated for the use in investigating original, historic works of art. The analysis of a sample from a Greek terracotta statue suggested that the white ground layer of the polychromy, still partly present today, contained a gum‐based binding medium. Furthermore, a procedure for the simultaneous analysis of oils, waxes and resins was applied to the identification of the composition of the varnish layer from the 16th century painting “Lucretia” by Jacopo Negretti (1480–1528). In addition, in a collaboration with the Department for Conservation and Restoration, University of Applied Arts, Vienna, a series of samples from paintings on wooden panels from the Buddhist temple complex in Nako, Himachal Pradesh, India, was investigated for the presence of proteinaceous binding media.
Inhibiting the Inevitable; Current Approaches to Slowing the Deterioration of Plastics
Authors: Shashoua Yvonne
Published: April 2006

Once plastics objects are registered in museum collections, the institution becomes responsible for their long term preservation, until the end of their useful lifetime. Plastics appear to deteriorate faster than other materials in museum collections and have a useful lifetime between 5 and 25 years. Preventive or inhibitive conservation involves controlling the environments in which objects are placed during storage and display, with the aim of slowing the major deterioration reactions. Once in progress, degradation of plastics cannot be stopped or reversed, so the aim of preventive conservation is to ‘buy time’ for the object. Inhibitive conservation of plastics involves the removal or reduction of factors causing or accelerating degradation including light, oxygen, acids, relative humidity and acidic breakdown products. Specific approaches to conservation have been developed for cellulose nitrate, cellulose acetate, PVC and polyurethanes by considering the most effective action to inhibit their major degradation pathways. The purpose of this article is to outline the main factors causing degradation of the least stable plastics in museum collections and present an overview of the conservation treatments established to date. Recent research has suggested that some of the conservation practices to slow the rate of deterioration in use today, particularly those for cellulose nitrate and acetate, are poorly effective and that alternatives should be evaluated. One alternative is low temperature storage.
Effectiveness of Graft Synthetic Polymers in Preventing Biodeterioration of Cellulose‐Based Materials
Authors: Cappitelli Francesca , Sorlini Claudia , Pedemonte Enrico , Princi Elisabetta , Vicini Silvia
Published: April 2006

Synthetic polymers have been occasionally applied to the consolidation and protection of paper and cellulose‐based textiles especially when traditional conservation methods were not sufficient to improve the mechanical resistance of the degraded artefacts. In this paper, the potential of the innovative technique of grafting polymerisation with synthetic polymers was investigated to prevent biodeterioration. Cotton, linen and Whatman paper were consolidated by a) coating Paraloid B72®, b) coating ethyl acrylate/methyl methacrylate (EA/MMA) preformed copolymer, and c) grafting onto cellulose chains EA and MMA monomers in the ratio 75/25. All the samples were artificially biodeteriorated to obtain biodegraded model samples of both consolidated and non‐consolidated substrates, according to the ASTM G21‐96(2002) “Standard Practice for Determining Resistance of Synthetic Polymeric Materials to Fungi”. The consolidating effect was examined evaluating the mechanical behaviour of the grafted and coated samples, before and after the artificial biodeterioration. In addition, SEM observations were applied to monitor both the grafting level and the biodeterioration of the samples. With the grafting of acrylic monomers, the mechanical strength of cellulose‐based textiles and paper was greatly improved, as well as the resistance to biological agents. Therefore, with regards to biodeterioration, the graft copolymer EA/MMA (75/25 wt) was proved to be a suitable method to help prevent possible deterioration of paper and textiles.
A wideband planar inverted‐F dielectric resonator antenna for RFID system applications
Authors: Tseng Ching‐Fang , Huang Cheng‐Liang , Hsu Cheng‐Hsing
Published: April 2006

This wideband planar inverted‐F dielectric resonator antenna (DRA) is proposed. The antenna provides two resonant paths of different lengths in order to achieve 2.4‐ and 5.8‐GHz dual‐band for radio frequency identification (RFID) system applications. The impedance bandwidth with 10‐dB return loss (2:1 VSWR) is about 255 MHz (2300–2555 MHz) for the 2.45‐GHz band and 835 MHz (5595–6430 MHz) for the 5.8‐GHz band. The obtained circular polarization (CP) bandwidths, determined from 3‐dB axial ratio, are about 180 MHz (about 7.35%) and 380 MHz (about 6.55%) at 2.45 and 5.8 GHz, respectively. Good antenna gain and circular‐polarization radiation patterns are also observed. The measured results of the performance of the antenna are presented. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1302–1305, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21616
Compact microstrip lowpass filter using a meander‐line structure
Authors: Su Guang Yi , Chan Chio Nang , Tam Un Leng , Tam Kam Weng
Published: April 2006

A novel compact microstrip lowpass filter using N‐turn meander line structure is proposed. This low pass filter provides a transmission zero near the passband edge and low passband insertion loss. Both the cutoff frequency and transmission zero can be easily controlled by changing the meander line dimensions to ease the filter design. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1339–1341, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21619
AnN‐bit digitally variable ultra‐wideband pulse generator for GPR and UWB applications
Authors: Yilmaz Sertac , Tekin Ibrahim
Published: April 2006

This paper presents a low‐cost ultra‐wideband (UWB) pulse generator that can vary the pulse duration digitally by using a step‐recovery diode (SRD), microstrip transmission lines, and PIN diodes. First, a sharp edge is generated by using SRD circuitry. Then a pulse is formed from the sharp edge through the use of transmission lines and the PIN diodes. Based on the number of transmission lines(N),the duration of the pulse can be varied in2Nsteps. The UWB pulse generator circuits are implemented on an FR‐4 substrate using microstrip‐line technology and UWB pulses with durations of 550 to 2400 psec are measured. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1334–1339, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21620
New optical receiver using two cascaded LiNbO3 Mach–Zehnder modulators as optical time‐division demultiplexer
Authors: Zhang Jian‐Guo , Tran D. D.
Published: April 2006

A new optical receiver is proposed for optical time‐division multiplexing (OTDM) systems, which uses two cascaded LiNbO3 Mach–Zehnder intensity modulators as an ultrafast electrooptic (EO) time gate to demultiplex the OTDM data. Compared to optical fiber‐based time‐division demultiplexers, the newly designed EO time gates have the advantages of compactness, low power consumption, and high operation stability. With the Gaussian approximation of time‐switching window for such EO gates, an analytical method is presented to efficiently evaluate the performance of this type of OTDM receiver employing PIN and avalanche photodiodes, respectively. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1326–1330, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21627
Reflections from almost‐periodic graded anisotropic slabs
Authors: Serebryannikov A. E. , Schuenemann K.
Published: April 2006

Results are presented for plane‐wave reflection from a 1D inhomogeneous anisotropic slab with components of the permittivity tensor obtained for a periodical arrangement of a finite number of Gaussian peaks, which results in an almost periodic profile. The interrelationship between the presence of band gaps (opaque ranges) in the transmission of left‐ and right‐hand polarized waves and the behaviour of two orthogonal components of the transverse electric field is demonstrated. It is shown that there are several typical scenarios with regard to the behaviour of these components and the related polarization conversion, which depend on the frequency range and on the type of the host medium. A Riccati differential equation is used for the calculations. The obtained results can be used to extend the potentials of polarization control. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1320–1324, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21629
A broadband reflectarray antenna with double square rings
Authors: Chaharmir M. R. , Shaker J. , Cuhaci M. , Ittipiboon A.
Published: April 2006

A reflectarray antenna composed of double square rings of variable lengths printed on a conductor‐backed substrate is proposed for reflectarray‐bandwidth enhancement. Using this technique, a single‐layer reflectarray of a wider bandwidth compared to conventional single‐layer reflectarrays is designed, fabricated, and measured. The measured results demonstrate a radiation efficiency close to 52% and 1‐dB gain bandwidth of 9%, centered at 22 GHz. © 2006 Government of Canada. Exclusive worldwide publication rights in the article have been transferred to Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1317–1320, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21630
Optical steering of a phased‐array antenna based on fast delay‐line switches
Authors: Jin Xiaofeng , Liu Juan , Liu Xiaomin , Zhang Xianmin
Published: April 2006

A kind of architecture of optical steering of a phased‐array antenna (PAA) based on a fast optical delay‐line switch is proposed and experimentally studied. A 4‐bit fast optical delay‐line switch with switching speed of less than 30 μs is constructed using cascaded solid‐state optical switches. A distributed feedback laser integrated with electro‐absorption modulator is employed for radio‐frequency feeding and delivery. Our experimental system of transporting X‐band microwave signals over one antenna element shows a signal‐to‐noise ratio better than 55 dB and low crosstalk of less than −50 dB. The structure features a compact design, a low‐cost solution, a fast tilting speed, and true‐time‐delay beam steering. The proposed scheme of optical steering is very promising for wideband X‐band PAA applications. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1449–1452, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21631
Dispersion induced effects of high‐order optical sidebands in the performance of millimeter‐wave fiber‐optic links
Authors: Pérez‐Millán Pere , Wiberg Andreas , Hedekvist Per Olof , Cruz José L. , Andrés Miguel V.
Published: April 2006

In this paper, chirped fiber Bragg gratings (CFBGs) are proposed as signal‐phase controllers for microwave‐photonic wireless downstream fiber links. The effect of high‐order modulation optical sidebands that disturbs the output mm‐wave signal due to the chromatic dispersion induced by the gratings is studied theoretically and experimentally. The 1st and 2nd mm‐wave harmonics of the output signal have been measured for conventional intensity modulation and for intensity modulation with optical carrier suppression. In the last case, data transmission at 2.5 Gb/s is demonstrated through a chirped grating of 280 ps/nm dispersion in a 40‐GHz modulated link. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1436–1441, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21634
SRR loaded waveguide band rejection filter with adjustable bandwidth
Authors: Jitha B. , Nimisha C. S. , Aanandan C. K. , Mohanan P. , Vasudevan K.
Published: April 2006

The use of a split‐ring resonator (SRR)‐loaded waveguide for the design of a band‐rejection filter with adjustable bandwidth is reported. The width of the stopband can be adjusted by suitably positioning the SRR array in the waveguide. The rejection band can be made very narrow by placing the array at the electric‐field minimum. The stopband attenuation depends on the number of unit cells in the array. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1427–1429, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21641
A method stabilizing the wavelength of mode‐locked fiber laser with injected continuous wave
Authors: Zhu Likai , Yu Jinlong , Wang Yaotian , Yang Enze
Published: April 2006

Stimulated by an injected continuous wave, a set of longitudinal modes wins the competition for gain medium continuously. In this paper, the linewidth of the longitudinal mode is broadened by the injected continuous wave. The wavelength of an actively mode‐locked fiber laser based on EDFA is stabilized in the experiment. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1385–1388, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21645
A 4th‐order accurate unconditionally‐stable IMS‐FDTD method with low numerical dispersion
Authors: Xiao Fei , Tang Xiaohong
Published: April 2006

This paper presents a 4th‐order accurate implicit multistage finite‐difference time‐domain (IMS‐FDTD) method. The analysis of the stability shows that this IMS‐FDTD method is unconditionally stable. In addition, its numerical‐dispersion relation is derived and the analysis shows that its performance is better than those of conventional unconditionally‐stable implicit FDTD methods and is even better than those of some conditionally‐stable explicit FDTD methods, such as the Fang(2, 4)‐FDTD method. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1383–1385, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21646
Photonic‐crystal‐fiber‐based Mach–Zehnder interferometer using long‐period gratings
Authors: Yu X. , Shum P. , Dong X.
Published: April 2006

We systematically analyze the mode‐coupling effects of stress‐induced long‐period gratings (LPGs) using photonic crystal fiber (PCF). Two Mach–Zehnder interferometers based on this grating are demonstrated. These devices offer the unique advantages of being tunable and reconfigurable. Their good interfering efficiency makes them promising for wavelength‐selective filters in WDM communication systems. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1379–1383, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21647
Design of tri‐band (EGSM/GPS/PCS) antenna with parasitic element for mobile‐phone application
Authors: Zhang Yabin
Published: April 2006

This paper proposed a novel design of tri‐band (EGSM/GPS/PCS) antenna for mobile phone application. The measured data and detailed antenna configure are available, too. The measured results show the design is successful and applicable. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1347–1350, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21651
A compact orthogonal tripolarized multiantenna with low mutual coupling for MIMO channel measurements
Authors: Yan Gang , Du Zhengwei , Gong Ke
Published: April 2006

A tripolarized multiantenna made up of three compact orthogonal dipoles is proposed. The three dipoles' phase centers are compact within 1/6 wavelength so that the spatial fading condition of the multi input multi output (MIMO) channel in subwavelength scale can be discriminated in three orthogonal directions of polarization by the multiantenna. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1358–1362, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21658
Multiwavelength comb generation in self‐starting passively mode‐locked fiber laser
Authors: Zhang Z. X. , Zhan L. , Xia Y. X.
Published: April 2006

Multiwavelength comb generation in an all‐fiber self‐starting passively mode‐locked figure‐eight erbium‐doped fiber laser is experimentally demonstrated. The nonlinear optical‐loop mirror (NOLM) consisting of a symmetrical optical coupler and a length of single‐mode fiber can act as the mode‐locking element through nonlinear polarization rotation. The linear ring with a section of polarization‐maintenance fiber and a polarization‐dependent isolator can implement linear filtering. Such a self‐starting passively mode‐locked erbium‐doped fiber laser can generate pulses with multiwavelength comb, which is characteristic of all‐fiber and simple configuration. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1356–1358, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21659
Research on a new type of UWB tapered slot antenna for receiving arrays
Authors: Wu Feng‐Tao , Yuang Nai‐Chang , Zhang Wei , Zhang Guang‐Fu
Published: April 2006

A new transition from coplanar waveguide (CPW) to slotline is introduced in an ultra‐wideband (UWB) tapered slot (printed) antenna (TSA) for receiving arrays. The difference between the UWB antenna‐array pattern and the conventional narrowband antenna pattern is clarified. The energy pattern and peak amplitude of the receiving waveform are used to characterize the behavior of UWB receiving antenna arrays. Patterns in the H‐plane are measured through an oscillograph; due to the difficulty of installation, the E‐plane pattern is not measured. The results indicate that the array can be used in the practical UWB radar for receiving antenna arrays. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1230–1233, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21663
Investigating the performance of MIMO systems from an electromagnetic perspective
Authors: Bialkowski Marek E. , Uthansakul Peerapong , Bialkowski Konstanty , Durrani Salman
Published: April 2006

Multiple input multiple output (MIMO) wireless systems use multiple element antennas (MEAs) at the transmitter (TX) and the receiver (RX) in order to offer improved information rates (capacity) over conventional single antenna systems in rich scattering environments. In this paper, an example of a simple MIMO system is considered in which both antennas and scattering objects are formed by wire dipoles. Such a system can be analyzed in the strict electromagnetic (EM) sense and its capacity can be determined for varying array size, interelement spacing, and distributions of scatterers. The EM model of this MIMO system can be used to assess the validity of single‐ or double‐bounce scattering models for mixed line of sight (LOS) and non‐line of sight (NLOS) signal‐propagation conditions. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1233–1238, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21664