bluuebunny/crossref_metadata_2025 huggingface dataset:
High‐salt diet and responses of the pressurized mesenteric artery of the dog to noradrenaline and acetylcholine
Authors: Sofola OA , Knill A , Myers D , Hainsworth R , Drinkhill MJ
Published: November 2004

1. A high‐salt diet in rats has been shown to result in enhanced vasoconstrictor and/or reduced vasodilator responses of isolated arteries to agonists. The present experiments were designed to investigate the effects of dietary salt on the responses of the pressurized mesenteric resistance artery of the dog to constrictor and dilator agents.

2. Dogs were fed diets containing three different levels of salt with sodium concentrations (in mmol/kg per day) of 0.4 (low salt; LS), 3.0 (intermediate salt; IS) and 6.0 (high salt; HS) for a period of 4 weeks. At the end of the feeding period, animals were killed and lengths of third‐order mesenteric artery were obtained and mounted in a perfusion myograph and changes in internal diameter were measured using a microscope and video‐tracking device. The responses to noradrenaline (NA), acetylcholine (ACh) and sodium nitroprusside (SNP) were then determined.

3. The vasoconstrictor responses to NA were identical in the three groups. However, the relaxation response of the vessels to ACh was attenuated in HS dogs compared with LS dogs (P < 0.05), but not with IS dogs. The application of NG‐nitro‐l‐arginine methyl ester, an inhibitor of nitric oxide synthase, reduced the relaxation responses to ACh comparably in all three groups. The relaxation responses of the vessels to SNP were similar in all groups.

4. These results indicate that, in the dog mesenteric resistance artery, a high‐salt diet does not affect vasoconstrictor responses to NA, but does attenuate the vasorelaxant action of ACh, largely by inhibiting the production of endothelium‐derived relaxing factor.
Upregulation of Fas/Fas ligand‐mediated apoptosis by gossypol in an immortalized human alveolar lung cancer cell line
Authors: Chang Jung‐San , Hsu Ya‐Ling , Kuo Po‐Lin , Chiang Lien‐Chai , Lin Chun‐Ching
Published: November 2004

1. Gossypol has wide antineoplastic effects in vitro, but its effects on human lung cancer have not been explored.

2. To evaluate the activity of gossypol against alveolar cell lung cancer and to provide information on the mechanism of action, we examined the effects of gossypol on the proliferation of A549 cells indirectly using an XTT assay and on the distribution of cells within the phases of the cell cycle using flow cytometry. We also examined several factors that may affect apoptosis, including p53, p21/WAF1, Fas receptor, Fas ligand (FasL) and caspase 8 activity.

3. The results showed that gossypol inhibited proliferation of A549 cells at a concentration of 0.5 µmol/L after 12 h treatment. The effect was both dose‐ and time‐dependent by the induction of apoptosis without the effect of p53 and p21/WAF1.

4. Upregulation of Fas/FasL, in association with the activation of downstream caspase 8 activity, was observed following treatment with gossypol. The Fas/FasL pathway accounted for 75% of gossypol‐mediated apoptosis.

5. We suggest that the Fas/FasL apoptotic system is the major pathway for gossypol‐mediated apoptosis of A549 cells.

6. Gossypol had no effect on the distribution of A549 cells within the phases of the cell cycle.

7. In conclusion, gossypol inhibited A549 cells mainly by induction of the Fas/FasL apoptotic pathway, but not the p53 and p21/WAF1 pathway.
Differences in the determinants of eplerenone, spironolactone and aldosterone binding to the mineralocorticoid receptor*
Authors: Rogerson Fraser M , Yao Yizhou , Smith Brian J , Fuller Peter J
Published: November 2004

1. The importance of mineralocorticoid receptor (MR) antagonists in the treatment of cardiovascular disease has been emphasised by two recent clinical trials, one using spironolactone and the other using a new selective MR antagonist, namely eplerenone.

2. Eplerenone has a very low affinity for the glucocorticoid receptor (GR). Determinants of binding specificity of eplerenone to the MR were investigated using chimeras created between the ligand‐binding domains (LBD) of the MR and the GR. These chimeras had been used previously to investigate aldosterone and spironolactone binding specificity to the MR.

3. Eplerenone competed strongly for [3H]‐dexamethasone binding to a MR/GR chimera containing amino acids 804–874 of the MR and weakly to a chimera containing amino acids 672–803 of the MR. Within the 804–874 region, eplerenone competed for [3H]‐dexamethasone binding to a chimera containing amino acids 820–844 of the MR, although the calculated affinity was approximately 10‐fold lower than for binding to the full‐length MR LBD. Similar results were obtained using another MR antagonist, namely spironolactone. Modelling of eplerenone binding to the MR LBD, based on the GR LBD crystal structure, suggests that amino acids 820–844 affect the overall shape of the ligand‐binding pocket and that eplerenone acts as an MR antagonist because it fails to stabilize the active conformation of the receptor.

4. In contrast with results with the MR antagonists eplerenone and spironolactone, amino acids 820–844 are sufficient in themselves to confer high‐affinity aldosterone binding to the MR, suggesting that the binding determinants of the two antagonists are similar to each other but differ from those of aldosterone.
Composition of freshwater bacterial communities associated with cyanobacterial blooms in four Swedish lakes
Authors: Eiler Alexander , Bertilsson Stefan
Published: November 2004

The diversity of freshwater bacterioplankton communities has not been extensively studied despite their key role in foodwebs and the cycling of carbon and associated major elements. In order to explore and characterize the composition of bacterioplankton associated with cyanobacterial blooms, large 16S rRNA clone libraries from four lakes experiencing such blooms were analysed. The four libraries contained 1461 clones, of which 559 were prokaryotic sequences of non‐cyanobacterial origin. These clones were classified into 158 operational taxonomic units affiliated mainly with bacterial divisions commonly found in freshwater systems, e.g. Proteobacteria, Bacteriodetes, Actinobacteria, Verrucomicrobia and Planctomycetes. Richness and evenness of non‐cyanobacterial clones were similar to other clone libraries obtained for freshwater bacterioplankton, suggesting that bacterial communities accompanying cyanobacterial blooms are as diverse as non‐bloom communities. Many of the identified operational taxonomic units grouped with known freshwater clusters but the libraries also contained novel clusters of bacterial sequences that may be characteristic for cyanobacterial blooms. About 25% of the operational taxonomic units were detected in more than one lake. Even so, 16S rRNA heterogeneity analysis demonstrated large differences in community composition between lakes regardless of their similar characteristics and close proximity. Hence even the similar environmental conditions created by different cyanobacterial blooms may foster very dissimilar bacterial communities, which could indicate that the genetic diversity in lake bacteria have been underestimated in the past.
Phylogenetic characterization ofLegionella‐like endosymbiotic X‐bacteria inAmoeba proteus: a proposal for ‘CandidatusLegionella jeonii’ sp. nov
Authors: Park Miey , Yun Seong Tae , Kim Mu Soo , Chun Jongsik , Ahn Tae In
Published: November 2004

The X‐bacteria which initiated organismic association with the D strain ofAmoeba proteusin 1966 as parasites have changed to obligate endosymbionts on which the host depends for survival. Owing to the difficulty in cultivating the bacteriain vitro, the identity of X‐bacteria has not been determined. As the life cycle of X‐bacteria is similar to that ofLegionellaspp. in soil amoebae, we applied the polymerase chain reaction method with specific primers aimed atLegionellaspp. for the detection and cloning of 16S rRNA gene. The identity and intracellular localization of the endosymbiont were confirmed by the application of a specific fluorescently labelled 16S rRNA‐targeted probe. In addition we cloned RNA polymerase β‐subunit gene (rpoB) of X‐bacteria by genomic library tagging. A phylogenetic analysis of the 16S rRNA gene placed the bacterium within a unique monophyletic group containing all other members of the genusLegionella. Phylogeny fromrpoBandmipgenes further confirmed the taxonomic context of X‐bacteria to be aLegionellasp. In all three phylogenic analyses, X‐bacterium was placed apart fromLegionella‐like amoebal pathogens present in soil amoebae. Thus, we propose the name ‘CandidatusLegionella jeonii’ sp. nov. for the endosymbiotic X‐bacteria inAmoeba proteus.
Alpha‐hydroxyacids and carboxylic acids
Authors: Yu Ruey J , Van Scott Eugene J
Published: November 2004

The carboxylic acids include alpha‐hydroxyacids (AHAs), polyhydroxy acids (PHAs), aldobionic acids (ABAs), retinoic acid, vitamin C and azelaic acid. They all have therapeutic actions.

AHAs, PHAs and ABAs are organic hydroxyacids, a group of natural and physiological substances which can modulate skin keratinization and increase biosynthesis of dermal components. Because of these effects, AHAs, PHAs and ABAs are therapeutically effective or beneficial for topical treatment of dry skin, rough skin, acne, rosacea, warts, eczema, psoriasis and skin changes associated with ageing, including wrinkles and photoageing. In addition, PHAs and ABAs, which are antioxidants, are topically beneficial for sensitive or diseased skin and for the prevention of oxidative damage caused by UV radiation.

The vitamin A derivatives, known as retinoids, include three that are found physiologically. Retinoic acid is the most potent of these in promoting proliferation and differentiation of epithelial cells, and in stimulating biosynthesis of collagen I and III. Because of these actions, retinoic acid is therapeutically effective for topical treatment of acne, actinic keratoses and photoaged skin.

Vitamin C, which is l‐ascorbic acid and a lactone form of 3‐keto‐polyhydroxy acid, is a water‐soluble antioxidant. Because of this property vitamin C has been promoted for topical prevention of skin damage caused by UV radiation.

Azelaic acid has been shown to normalize keratinization in the follicular infundibulum, exert an antibacterial effect against Propionibacterium acnes and inhibit melanogenesis and so has been used for topical treatment of acne and melasma. The carboxylic acids display similarities and differences in their topical actions and therapeutic applications.
Body dysmorphic disorder and cosmetic dermatology: more than skin deep
Authors: Castle David J , Phillips Katharine A , Dufresne Raymond G
Published: November 2004

Body dysmorphic disorder (BDD) is relatively common in cosmetic practise, yet it remains under‐recognized.

BDD patients are unnaturally concerned with minimal or non‐existent flaws, most commonly in the skin (e.g. facial acne or scarring) and hair (e.g. hair loss). Many patients develop social avoidance and suffer occupational or academic impairment. More severely ill patients may become housebound or even attempt suicide. Despite the minimal or non‐existent nature of the perceived appearance flaws, patients with BDD may request dermatological treatments such as isotretinoin or dermabrasion. Although treatment outcome has received little investigation, it appears that most patients are dissatisfied with dermatological treatment and, even if the outcome is objectively acceptable, they do not worry any the less about their appearance afterwards.

In contrast, a majority of patients respond to serotonin reuptake inhibitors or cognitive behavioural therapy. Treatment of these patients is best given by an experienced health professional. This may be a mental health professional or a dermatologist with an interest in psychological medicine.
Within‐plant vertical distributions of the scale insectNipponaclerda biwakoensisand its five parasitoids that exhibit frequent successful multiparasitism on the common reed
Authors: KANEKO Shuji
Published: November 2004

Within‐shoot vertical distributions of the scale insectNipponaclerda biwakoensis, five species of gregarious parasitoid wasps attacking the scale, and successful multiparasitism (emergence of multiple parasitoid species from a single host) by the parasitoids on the common reed were investigated. Each reed shoot collected was longer than 2.0 m, and was divided into pieces of 0.5 m each from the base of the shoot. The mean number of adult female scales per 0.5 m of shoot increased with height, but the mean rate of overall parasitism of the female scales decreased with height. The five parasitoids showed species‐specific within‐shoot distribution patterns, with respect to the rate of parasitism:Astymachus japonicus,Boucekiella depressaand Encyrtidae sp. 2 showed the greatest rates of parasitism at heights of 0–0.5, 0.5–1.0 and 1.0–1.5 m, respectively. The parasitism rate byAprostocetussp. was higher at the lower half of the shoots, whereas that by Encyrtidae sp. 1 was higher at the central positions. The distribution of the five parasitoids largely overlapped with each other at the level of scale aggregations. Nevertheless, successful multiparasitism occurred frequently only in several types of species combinations that involved two parasitoid species showing similar within‐shoot distribution patterns. The rate of successful multiparasitism byB. depressawithA. japonicusorAprostocetussp., and that by Encyrtidae sp. 2 with Encyrtidae sp. 1 was constantly high at different vertical positions on the shoots. This may be becauseB. depressaand Encyrtidae sp. 2 preferentially oviposit into scales previously parasitized by these other species.
Effects of selective logging on the arboreal ants of a Bornean rainforest
Authors: WIDODO Erwin S. , NAITO Tikahiko , MOHAMED Maryati , HASHIMOTO Yoshiaki
Published: November 2004

We examined the effect of selective logging and corresponding forest canopy loss on arboreal ant diversity in a tropical rainforest. Arboreal ants were collected from an unlogged forest plot and from forest plots selectively logged 14 years and 24 years earlier in Danum Valley, Sabah, Malaysia, using a canopy fogging method. Selective logging was associated with a significant decrease in canopy cover and an increase in understory vegetation density relative to unlogged forest. Our study showed that selective logging in primary forest might not dramatically decrease total species number and overall abundance of arboreal ants; however, it may influence the species composition and dominance structure of the ant community, accompanied by an increase in abundance of shrub‐layer species and trophobiotic species. In view of the results of this study, management techniques that minimize logging impact on understory vegetation structure are likely to help maintain the conservation value of logged forests for arboreal ants. Our results also suggest that accurate assessment of the impacts on biodiversity should not be based only on measurement of species number and overall abundance, but also on analysis of species composition and community structure.
Immunoisolated Chromaffin Cells Implanted Into the Subarachnoid Space of Rats Reduce Cold Allodynia in a Model of Neuropathic Pain: A Novel Application of Microencapsulation Technology
Authors: Kim Yu Mi , Jeon Young Hoon , Jin Gwang Chun , Lim Jeong Ok , Baek Woon Yi
Published: November 2004

Abstract:  Intrathecal transplants of adrenal medullary chromaffin cells relieve chronic pain by secreting catecholamines, opioids, and other neuroactive substances. Recently, macrocapsules with semipermeable membranes were used to isolate immunologically xenogenic chromaffin cells, but the poor viability in vivo of the encapsulated chromaffin cells limited the usefulness of this method. In this study, we used a novel method of encapsulation to increase the viability of chromaffin cells. We found that microencapsulated chromaffin cells that were implanted into the subarachnoid space of rats relieved cold allodynia in a model of neuropathic pain. Furthermore, microencapsulated chromaffin cells were morphologically normal and retained their functionality. These findings suggest that the intrathecal placement of microencapsulated chromaffin cells might be a useful method for treating chronic pain.
Four Years’ Experience With a Miniaturized Extracorporeal Circulation System and Its Influence on Clinical Outcome
Authors: Wiesenack Christoph , Liebold Andreas , Philipp Alois , Ritzka Markus , Koppenberg Joachim , Birnbaum Dietrich E. , Keyl Cornelius
Published: November 2004

Abstract:  It has been suggested that the morbidity associated with cardiopulmonary bypass can be attributed in part to the blood–material and blood–air interactions in the extracorporeal circulation (ECC). A recently introduced minimized ECC‐system (MECC System) should be able to reduce these negative effects associated with ECC. A retrospective analysis was performed comprising 485 patients who were operated on for elective coronary artery bypass grafting (CABG) using the MECC System with intermittent antegrade warm blood cardioplegia (group 1) from January 2000 to February 2004. A control group consisted of 485 patients (group 2) undergoing elective CABG in the same period using a conventional ECC and cold crystalloid cardioplegia. There were no significant differences between the two groups in terms of the duration of intubation following surgery, the length of intensive care unit‐stay and the total hospital stay. Although the 30‐day mortality was similar between the two groups, the incidence of postoperative complications and the perioperative use of blood products were significantly higher in the control group compared to the MECC group. The MECC System may serve as an alternative and less invasive approach to conventional ECC.
Acute Hemodynamic Study of Tai‐Ta Left Ventricular Assist Device in a Canine Model
Authors: Shyu Jeou‐Jong , Chou Nai‐Kuan , Lee Chun‐Jean , Chen Chi‐Fu , Shau Yio‐Wha , Wang Shoei‐Shen , Chu Shu‐Hsun
Published: November 2004

Abstract:  A revised Tai‐Ta centrifugal impeller pump was designed to study the interaction of the left ventricular assist device (LVAD) with the cardiovascular system in a canine model. Six healthy dogs weighing 12–16 kg were used. Blood flows in the aortic arch, the pulmonary artery (PA), and the LVAD outlet were measured simultaneously with the arterial blood pressure (ABP), the pump outflow pressure (POP), and the electrocardiograph (ECG). Normally, the blood flows in the aorta and the PA started at the S‐wave of the ECG. When the LVAD was operated at a higher rotational speed (increased from 2900 to 5400 rpm), the ABP, POP, the pump flow, and the maximum rate of change of PA flow increased. However, the fluctuating amplitudes of ABP, POP, and the pump flow decreased significantly. The cardiovascular hemodynamics change with the pump speeds. For a typical 1.1–1.5 L/min cardiac output in canine, the revised LVAD was able to deliver a flow bypass ratio from 15% up to 100%. The LVAD outflow appeared to be pulsatile and matched the cardiac cycle, showing that the centrifugal impeller pump could be used as a pediatric assist device when cardiac function was impeded.
The plaque‐removing efficacy of a finger brush (I‐Brush®)
Authors: Graveland M. P. , Rosema N. A. M. , Timmerman M. F. , Van der Weijden G. A.
Published: November 2004

Objective: The purpose of the present study was to test the effectiveness of a finger toothbrush (I‐Brush®) in removing plaque compared with a flat‐trimmed manual toothbrush.

Material and methods: For this study, 37 subjects were selected, without previous experience of the use of the I‐Brush®. Each subject received a finger brush (I‐Brush®), a manual toothbrush (Butler® GUM 311), two written brushing instructions for both types of brushes, and a brush calendar. Subjects were given a period of 3 weeks to become familiar with the two types of brushes. During this period, the subjects were instructed to use the two types of brushes on alternate days. The brush calendar helped as a reminder and served to ensure compliance. No instructions regarding brushing time or frequency of brushing were given to the subjects, except that they should conform to their usual oral habits. After 3 weeks, all subjects were asked to abstain from oral hygiene procedures for 48 h prior to the experiment. In this experiment, the amount of dental plaque was scored by a trained examiner. The examiner (N.A.M.R.) used the modified Silness & Löe (1964) plaque index at six sites per tooth. After scoring, each subject received a new finger brush and a new manual toothbrush. The subjects brushed according to a split mouth protocol. Two contra‐lateral quadrants were chosen randomly and were brushed with one randomly chosen brush and the two opposing contra‐lateral quadrants with the alternate brush. The brushing was performed under supervision in front of a mirror. The available time for brushing was 2 min. for the entire dentition. Finally, the remaining plaque was scored again.

Results: The overall reduction in plaque was 79% for the manual toothbrush and 62% for the finger brush. The plaque removing efficacy of the finger brush was poorest at the approximal vestibular surfaces (55% plaque reduction) compared with the manual toothbrush (77% plaque reduction).

Conclusion: The plaque reduction of the finger brush is not an acceptable alternative to the use of a regular manual toothbrush.
Subgingival plaque microbiota in Saudi Arabians after use of miswak chewing stick and toothbrush
Authors: Al‐Otaibi M. , Al‐Harthy M. , Gustafsson A. , Johansson A. , Claesson R. , Angmar‐Månsson B.
Published: November 2004

Background: The chewing stick, the miswak, is used in many developing countries as the traditional means for oral hygiene. It is prepared from the roots, twigs and stem of Salvadora persica or other alternative local plants.

Objectives: To compare the effects of the chewing stick miswak (from S. persica) and toothbrush on subgingival plaque microflora among Saudi Arabian individuals. Further, to investigate whether components extracted from S. persica may interfere with the subgingival plaque micro‐organisms.

Material and Methods: Fifteen healthy Saudi Arabian male volunteers aged 21–36 years were included in a single‐blind, randomized cross‐over study. The participants were taught how to use each device properly. Plaque sampling for DNA test was performed at the baseline, 1 week after professional tooth cleaning, and after 3 weeks of either miswak or toothbrush use. Identification and quantification of microbial species were performed by the checkerboard method, using whole genomic, digoxigenin‐labelled DNA probes. Inhibition zones around miswak were examined on agar plates with Actinobacillus actinomycetemcomitans and the leukotoxicity of this bacterium was analyzed in a bioassay with macrophages±extracts of miswak.

Results: Miswak and toothbrushing had a similar influence on the levels of the subgingival microbiota. However, A. actinomycetemcomitans was significantly more reduced by miswak (p<0.05) than by toothbrushing. These results were supported by our in vitro results which, indicated that extracts from S. persica might interfere with the growth and leukotoxicity of A. actinomycetemcomitans.

Conclusions: In contrast to toothbrush use, miswak use significantly reduced the amount of A. actinomycetemcomitans in the subgingival plaque.
In vitro studies on controlled‐release cellulose acetate films for local delivery of chlorhexidine, indomethacin, and meloxicam
Authors: Çetin Emel Öykü , Buduneli Nurcan , Atlıhan Evren , Kırılmaz Levent
Published: November 2004

Background: Delivery of medications into periodontal pockets to suppress or eradicate the pathogenic microbiota or modulate the inflammatory response, thereby limiting periodontal tissue destruction, has attracted significant interest with the purpose of effective periodontal treatment. However, no study has previously attempted to develop a controlled‐release formulation of anti‐inflammatory agents to be used in the field of periodontology. The aim of the present study was to examine the in vitro release profile of chlorhexidine gluconate, indomethacin, and meloxicam from cellulose acetate films.

Methods: Cellulose acetate films containing chlorhexidine gluconate, indomethacin, and meloxicam were prepared and cut in a form to fit to the periodontal pocket anatomy. The release of active agents was studied in 10 ml artificial saliva at 37°C. Apparatus Vibrax was used at 150 r.p.m. Determinations were carried out spectrophotometrically and the release profiles were plotted as a function of time.

Results: The formulations showed two different release patterns for a total observation period of approximately 120 h. When the formulations of the three active agents were compared, the release patterns of meloxicam and chlorhexidine gluconate were found to be similar, while the indomethacin‐containing formulation exhibited the fastest release rate.

Conclusions: As a conclusion, cellulose acetate may be a suitable inert material for obtaining a prolonged local release of various anti‐inflammatory agents like meloxicam. Further in vitro and in vivo studies are required before starting clinical applications of these controlled‐release formulations of anti‐inflammatory agents.
Neutrophils contribute to muscle injury and impair its resolution after lengthening contractions in mice
Authors: Pizza Francis X. , Peterson Jennifer M. , Baas Joel H. , Koh Timothy J.
Published: November 2004

We tested the hypotheses that: (1) neutrophil accumulation after contraction‐induced muscle injury is dependent on the β2 integrin CD18, (2) neutrophils contribute to muscle injury and oxidative damage after contraction‐induced muscle injury, and (3) neutrophils aid the resolution of contraction‐induced muscle injury. These hypotheses were tested by exposing extensor digitorum longus (EDL) muscles of mice deficient in CD18 (CD18−/−; Itgb2tm1Bay) and of wild type mice (C57BL/6) to in situ lengthening contractions and by quantifying markers of muscle inflammation, injury, oxidative damage and regeneration/repair. Neutrophil concentrations were significantly elevated in wild type mice at 6 h and 3 days post‐lengthening contractions; however, neutrophils remained at control levels at these time points in CD18−/− mice. These data indicate that CD18 is required for neutrophil accumulation after contraction‐induced muscle injury. Histological and functional (isometric force deficit) signs of muscle injury and total carbonyl content, a marker of oxidative damage, were significantly higher in wild type relative to CD18−/− mice 3 days after lengthening contractions. These data show that neutrophils exacerbate contraction‐induced muscle injury. After statistically controlling for differences in the force deficit at 3 days, wild type mice also demonstrated a higher force deficit at 7 days, a lower percentage of myofibres expressing embryonic myosin heavy chain at 3 and 7 days, and a smaller cross sectional area of central nucleated myofibres at 14 days relative to CD18−/− mice. These observations suggest that neutrophils impair the restoration of muscle structure and function after injury. In conclusion, neutrophil accumulation after contraction‐induced muscle injury is dependent on CD18. Furthermore, neutrophils appear to contribute to muscle injury and impair some of the events associated with the resolution of contraction‐induced muscle injury.
United Time-Frequency Spectroscopy for Dynamics and Global Structure
Authors: Marian Adela , Stowe Matthew C. , Lawall John R. , Felinto Daniel , Ye Jun
Published: November 2004

Ultrashort laser pulses have thus far been used in two distinct modes. In the time domain, the pulses have allowed probing and manipulation of dynamics on a subpicosecond time scale. More recently, phase stabilization has produced optical frequency combs with absolute frequency reference across a broad bandwidth. Here we combine these two applications in a spectroscopic study of rubidium atoms. A wide-bandwidth, phase-stabilized femtosecond laser is used to monitor the real-time dynamic evolution of population transfer. Coherent pulse accumulation and quantum interference effects are observed and well modeled by theory. At the same time, the narrow linewidth of individual comb lines permits a precise and efficient determination of the global energy-level structure, providing a direct connection among the optical, terahertz, and radio-frequency domains. The mechanical action of the optical frequency comb on the atomic sample is explored and controlled, leading to precision spectroscopy with an appreciable reduction in systematic errors.
A RULE-BASED NEURAL CONTROLLER FOR INVERTED PENDULUM SYSTEM
Authors: HAO JIANBIN , VANDEWALLE JOOS , TAN SHAOHUA
Published: November 2004

This paper tries to demonstrate how a heuristic neural control approach can be used to solve a complex nonlinear control problem. The control task is to swing up a pendulum mounted on a cart from its stable position (vertically down) to the zero state (up right) and keep it there by applying a sequence of two opposing constant forces of equal magnitude to the mass center of the cart. In addition, the displacement of the cart itself is confined to within a preset limit during the swinging up action and it will eventually be brought to the origin of the track. This is truly a nontrivial nonlinear regulation problem and is considerably difficult compared to the pendulum balancing problem (and its variations) widely adopted as a benchmarking test system for neural controllers. Through the solution of this specific control problem, we try to illustrate a heuristic neural control approach with task decomposition, control rule extraction and neural net rule implementation as its basic elements. Specializing to the pendulum problem, the global control task is decomposed into subtasks namely pendulum positioning and cart positioning. Accordingly, three separate neural subcontrollers are designed to cater to the subtasks and their coordination, i.e., pendulum subcontroller (PSC), cart subcontroller (CSC) and the switching subcontroller (SSC). Each of the subcontrollers is designed based on the rules and guidelines obtained from the experiences of a human operator. The simulation result is included to show the actual performance of the controller.
CONTROL OF THE COMPLEXITY OF ASSOCIATIVE MEMORY DYNAMICS BY NEURONAL ADAPTATION
Authors: CARTLING BO
Published: November 2004

An abstract neural network model of the Hopfield type is extended to incorporate neuronal adaptation by defining the state of a neuron in terms of two variables, activity and excitability. The model is formulated to represent the regulation of the firing rate of action potentials in a biological system via the neuron cell membrane afterhyperpolarization by the effect of intracellular calcium ion concentration on the conductance of calcium sensitive potassium channels. It is shown that the complexity, and thus the exploratory degree, of associative memory dynamics are controlled by neuronal adaptability. At low adaptability, the dynamics have fixed point attractors corresponding to direct memory retrieval. In a subsequent region of adaptability values, a simple limit cycle persists with frequency increasing with adaptability. The range of frequencies agrees with that observed for theta rhythms of activity in the brain. A higher degree of freedom of the associative process corresponding to more complex dynamics, either limit cycles of varying complexity and period or chaotic behaviour, results at higher adaptability. In the brain, the neuronal adaptability is regulated by neuromodulators which suppress adaptation and increase absolute firing rates of action potentials. An associative process can be started at low concentration of neuromodulators as an exploratory search of state space during which firing rates are low. As the concentration of neuromodulators increases, the state space search becomes simpler cyclic and more restricted, and firing rates increase. Eventually, a particular stored state is retrieved and its activity is high. This correspondence between the complexity of associative memory dynamics and the concentration of neuromodulators is consistent with the observation for Alzheimer's disease of selective degeneracy of neurons releasing the neuromodulator acetylcholine. In an artificial neural network, inclusion of adaptation among neuronal properties allows control of the degree of freedom of associative processes and thus extends the range of possible applications.
A QUANTITATIVE STUDY OF PRUNING BY OPTIMAL BRAIN DAMAGE
Authors: GORODKIN J. , HANSEN L. K. , KROGH A. , SVARER C. , WINTHER O.
Published: November 2004

The optimal brain damage (OBD) scheme of Le Cun, Denker and Solla for pruning of feedforward networks has been implemented and applied to the contiguity classification problem. It is shown that OBD improves the learning curve (the test error as a function of the number of examples). By inspecting the architectures obtained through pruning, it is found that the networks with less parameters have the smallest test error in agreement with "Ockhams Razor". Based on this, we propose a heuristic which selects the smallest successful architecture among a group of pruned networks and we show that it leads to very efficient optimization of the architecture. The validity of the approximations involved in OBD are discussed and it is found that they are surprisingly accurate for the problem studied.
TRANS-DIMENSIONAL LEARNING
Authors: ROMANIUK STEVE G.
Published: November 2004

The main objective of this research paper is to introduce a novel approach to pattern classification across multiple dimensions. Trans-dimensional learning is concerned with automatically determining network architectures that can generalize not only for fixed-dimensional problems but take a profound step by exemplifying how learning an unrestricted number of problems — which differ in the dimensionality of their input space N — can be accomplished. Relaxing the classification of network units as inputs hidden and outputs leads to the notion of all units of a network being features. Learning is perceived as the process of creating features and integrating these with other constructed features to form a self-adjusting network which can build on prior learned knowledge. This feat is accomplished by utilizing the simple perceptron rule for local feature training and incorporating evolutionary processes for determining suitable partitions to train individual features on. The basic algorithm introduced here (TDL) is augmented by single feature pruning to further reduce network complexity. An array of experiments is presented to emphasize the learning capabilities of TDL.
A FLEXIBLE AND FAULT TOLERANT QUERY-REPLY SYSTEM BASED ON A BAYESIAN NEURAL NETWORK
Authors: HOLST ANDERS , LANSNER ANDERS
Published: November 2004

A query-reply system based on a Bayesian neural network is described. Strategies for generating questions which make the system both efficient and highly fault tolerant are presented. This involves having one phase of question generation intended to quickly reach a hypothesis followed by a phase where verification of the hypothesis is attempted. In addition, both phases have strategies for detecting and removing inconsistencies in the replies from the user. Also described is an explanatory mechanism which gives information related to why a certain hypotheses is reached or question asked. Specific examples of the systems behavior as well as the results of a statistical evaluation are presented.
NEURAL STRATEGIES TO HANDLE ROUTING IN COMPUTER NETWORKS
Authors: CAVALIERI S. , DI STEFANO A. , MIRABELLA O.
Published: November 2004

In this paper, the authors adopt a neural approach to deal with the problem of routing in a packet switching network. The aim is to define a routing strategy which will combine the advantages of both the centralized and the distributed approaches. The neural approach presented is based on the idea of inserting a neural network (N/N) into each node in the computer network which will be responsible for computing the route between its node and the immediately adjacent one. Two distributed routing solutions are presented in the paper based on an optimizing network and a mapping network. The routing obtainable and the implementation resources needed for the two approaches are evaluated. Finally, the performance offered by the neural strategies proposed is compared with that offered by classical distributed and centralized routing solutions. As a parameter of merit, the effect of overloading caused by the additional traffic present in each solution is used.
RECENT DEVELOPMENTS IN NEURODYNAMICS AND THEIR IMPACT ON THE DESIGN OF NEURO-CHIPS
Authors: RAMACHER ULRICH , SCHILDBERG PETER
Published: November 2004

Neurons can be modeled either by equations or differential equations. For the latter, a low-pass filter must be added to the analog function blocks associated with the McCullogh and Pitts type of static neuron in order to provide the time-dependent neuron solution. The low-pass filter enhances stability and enables a time-continuous analog implementation much more compact than that attained with time-discrete analog or pure digital design. A few examples of equations as well as differential equations are known for that part of learning. However, much less than for the recall mode, it is clear how to design learning neuro-chips for temporal pattern processing. It is shown here that a partial differential equation can be used to provide a unified description of both the recall and learning dynamics of a neural network as well as to investigate systematically the VLSI potential for analog time-continuous neuro-chips. It turns out that the recall and learning dynamics can be divided into causal as well as noncausal solutions. The first type of solution includes oscillating or spiking neurons. The second type of solution allows for a much simpler signal representation but leads to the problem of storing the temporal signal of each neuron for as long a time as a single pattern lasts. As this is prohibitive for larger networks and time-varying patterns, the analog VLSI implementation of causal neuron models is suggested.
NEURAL NETWORK FEATURE DETECTOR FOR REAL-TIME VIDEO SIGNAL PROCESSING
Authors: NAYLOR DAVID , JONES SIMON , MYERS DAVID , VINCENT JOHN
Published: November 2004

The application of artificial neural networks to real-time image processing tasks requires the use of dedicated, high performance hardware. A linear array processor called HANNIBAL has been developed which implements the backpropagation neural learning algorithm on-chip. This paper considers the design of a complete neural system which integrates HANNIBAL into an existing image processing environment. The goals for the design of the system have been set partly by the primary application, namely feature recognition, but mainly by the desire for a flexible, high performance hardware tool for the study and evaluation of range of neural image processing applications.
A HARDWARE EFFICIENT CASCADABLE CHIP SET FOR ANN'S WITH ON-CHIP BACKPROPAGATION
Authors: LEHMANN TORSTEN
Published: November 2004

In this paper, an analogue, cascadable, CMOS chip set for artificial neural networks is presented. The chip set (a synapse chip and a neuron chip) offer on-chip back-propagation learning in a fully parallel, layered, feedforward network of arbitrary size and topology. The learning scheme is implemented with no extra circuits at the synapse sites (compared to the system without the learning scheme) and extra circuits of a complexity only about the same as the neurons at the neuron sites. Also, no additional wiring is required by the learning scheme. Measurements on an experimental chip set are presented.
ANALOGUE SYNAPTIC NOISE — IMPLICATIONS AND LEARNING IMPROVEMENTS
Authors: EDWARDS PETER J. , MURRAY ALAN F.
Published: November 2004

We analyse the effects of analogue noise on the synaptic arithmetic during multilayer perceptron training by expanding the cost function to include noise-mediated penalty terms. Predictions are made in the light of these calculations which suggest that fault tolerance, generalisation ability and learning trajectory should be improved by such noise-injection. Extensive simulation experiments on two distinct classification problems substantiate the claims. The results appear to be perfectly general for all training schemes where weights are adjusted incrementally, and have wide-ranging implications for all applications, particularly those involving "inaccurate" analogue neural VLSI.
PIXE ANALYSIS OF TRACE AND MAJOR ELEMENTS IN ATMOSPHERIC AEROSOL PARTICLES AT THREE DIFFERENT SITES OF DEBRECEN CITY, HUNGARY
Authors: ALI A. , BORBÉLY-KISS I. , SZABÓ GY. , KOLTAY E. , MEDVE F. , BACSÓ J.
Published: November 2004

Samples of atmospheric aerosol particles collected at three sites of Debrecen city, were analyzed with respect to 15 elements by PIXE method. The center of the city has higher concentration values for most of the trace elements than the other places, indicating that the human activity plays an important role in increasing the total particulate mass of atmospheric aerosol. The concentrations measured are compared to some other results in published literatures.
ELEMENTAL ANALYSIS OF MOUSE HAIR BY PIXE METHOD
Authors: TAMANOI ITSURO , OOHASHI KUNIO , MATSUMOTO SHINJI , MURAKOSHI ZENJI , MATSUMOTO TUNEYA
Published: November 2004

Constitutional elements of head hair of mouse (Mus musculus) were investigated by Particle-Induced X-ray Emission (PIXE) analysis. The high peaks of S, K and Ca, and the low peaks of several other elements were observed in PIXE spectra of all the specimens from the used strains. The result clearly indicates that the ratios of these elemental contents are different among the coat colors of mice. Further, we observed strain difference even in the same color.
APPLICATION OF PIXE- AND RBS-CHANNELING TO INVESTIGATIONS ON THE CHARACTERIZATION OF SINGLE CRYSTAL STAINLESS STEEL
Authors: NAKAE T. , TAKAHASHI R. , NOMURA T. , NAKAI Y. , KAGEYAMA H. , SHIMATANI N. , AWATA T. , NISHIHATA A. , ARAI S. , KAWATSURA K. , HORINO Y. , MOKUNO Y. , FUJII K. , AOKI Y. , TAKESHITA H. , YAMAMOTO S. , GOPPELT-LANGER P. , NARAMOTO H. , MITAMURA T. , TERASAWA M. , UCHIDA H. , KOTERAZAWA K.
Published: November 2004

The characterization of the single crystal of type 304 stainless steels was performed by using particle induced x-ray emission and Rutherford backscattering spectroscopy with channeling technique (PIXE-C and RBS-C). They proved that the solution annealing process is absolutely necessary for production of a good single crystal of stainless steels.

They are also shown that the positions of P atoms before He irradiation were mostly substitutional sites of fcc structure and that MeV He ion irradiation induced segregation of Si and S atoms to the (110) surface.
SEMIEMPIRICAL FORMULAS FOR CALCULATION OF L SUBSHELL IONIZATION CROSS SECTIONS
Authors: ORLIĆ I. , SOW C.H. , TANG S.M.
Published: November 2004

Presented are new parameters for the calculation of L subshell ionization cross sections for proton impact using a semiempirical expression. A similar paper was published by our group in early 1993 but the fitting parameters were obtained by using only 2295 experimental L shell cross section data. Since then a large number of experimental data have become available and therefore a new fitting has been performed employing more than 5000 data points. All available data were fitted separately for L1, L2 and L3 subshells. For targets with low atomic numbers (14≤Z≤42), only coefficients for L tot were obtained. Because of the slight Z dependence of the universal function, data were also devised into five sub-groups according to their atomic numbers and fitted separately within each group for L1, L2 and L3 subshells. To extend the energy range of validity of the new fitting function theoretical values were used in the high energy region where experimental data were lacking. Results are compared with ECPSSR predictions and discussed.
EFFECTS OF Zn-DTPA ON ESSENTIAL TRACE METALS IN RATS
Authors: SATO I. , MATSUSAKA N. , KOBAYASHI H. , SERA K. , FUTATSUGAWA S. , NISHIMURA Y.
Published: November 2004

Zn-DTPA was injected intraperitoneally into rats (30 µmol/kg) with a single dose or a daily dose for 10 consecutive days. Urine samples were collected for 24 hours after the single injection and tissue samples were excised 20 hours after the final of the consecutive injections. Elements in these samples were analyzed by PIXE. Zn-DTPA raised the urinary concentration of zinc and copper, and their urinary losses caused by Zn-DTPA were estimated to be 1.9 and 0.01 mg/30μmol Zn-DTPA, respectively. The concentration of metals in the liver, kidneys, brain and femurs remained unchanged. These results suggest that almost all of Zn-DTPA is excreted into the urine without replacement with other metals, and so this chelating agent may not induce any deficiencies of essential metals when animals are treated with a dose of 30 µmol/kg per day.
THE PROGRESS AND PERFORMANCE OF LONG WAVELENGTH OEIC PHOTORECEIVERS INCORPORATING HETEROJUNCTION BIPOLAR TRANSISTORS
Authors: CHANDRASEKHAR S.
Published: November 2004

Long wavelength optoelectronic integrated circuits have made impressive progress in the last decade and their performance has become attractive enough to be considered as part of lightwave communication systems. This paper reviews these aspects of OEICs, with emphasis on monolithic photoreceivers which incorporate heterojunction bipolar transistors for electronic functions. We cover applications covering both direct detection as well as coherent detection, discuss implementation methodologies, compare performances with hybrid receivers, briefly look into noise issues, and speculate on future directions.
LOW-POWER, LOW-VOLTAGE DESIGN—AN OVERVIEW
Authors: RAZAVI BEHZAD
Published: November 2004

This paper gives an overview of design issues in low-power, low-voltage circuits. First, device and supply scaling is studied and its impact on both digital and analog circuits is described. Next, general low-power and low-voltage design strategies are presented. Finally, two examples of high-speed, low-power circuits are discussed.
VERTICAL CAVITY SURFACE EMITTING LASERS WITH DIELECTRIC MIRRORS
Authors: SCHERER A. , O’BRIEN J. , ALMOGY G. , XU W.-H. , YARIV A. , JEWELL J.L. , UOMI K. , YOO B.J. , BHAT R.J.
Published: November 2004

We have developed new low threshold surface emitting laser designs with dielectric high reflectivity top mirrors. Here, we describe the characteristics of these surface emitting vertical cavity lasers (VCSELs) which exhibit stable mode patterns and low threshold currents. The new device fabrication sequence which we employ is able to adjust the emission wavelength of the lasers during the final fabrication step and allow the development of stable multi-wavelength laser arrays. These quantum-well based laser diodes are demonstrated at 0.72 μm with threshold currents of 20 mA, at 0.85 μm with threshold currents of 3 mA, at 0.98 μm with threshold currents of 4 mA, and at 1.55 μm with threshold currents of 17 mA. Our VCSELs also display remarkably low threshold voltages, thus minimizing the laser power dissipation and improving the wallplug efficiency. The flexibility resulting from depositing one or both of the mirrors after the fabrication of the laser diodes opens the way to the development of new and more versatile laser structures.
TOWARD AUTOMATIC DISTRIBUTION
Authors: FEAUTRIER PAUL
Published: November 2004

This paper considers the problem of distributing data and code among the processors of a distributed memory supercomputer. Provided that the source program is amenable to detailed dataflow analysis, one may determine a placement function by an incremental analogue of Gaussian elimination. Such a function completely characterizes the distribution by giving the identity of the virtual processor on which each elementary calculation is done. One has then to “realize” the virtual processors on the PE. The resulting structure satisfies the “owner computes” rule and is reminiscent of two-level distribution schemes, like HPF’s [Formula: see text] and [Formula: see text] directives, or the CM-2 virtual processor system.