bluuebunny/crossref_metadata_2025 huggingface dataset:
Defining Trade‐Offs among Conservation, Profitability, and Food Security in the California Current Bottom‐Trawl Fishery
Authors: HILBORN RAY , STEWART IAN J. , BRANCH TREVOR A. , JENSEN OLAF P.
Published: March 2012

Abstract:  Although it is recognized that marine wild‐capture fisheries are an important source of food for much of the world, the cost of sustainable capture fisheries to species diversity is uncertain, and it is often questioned whether industrial fisheries can be managed sustainably. We evaluated the trade‐off among sustainable food production, profitability, and conservation objectives in the groundfish bottom‐trawl fishery off the U.S. West Coast, where depletion (i.e., reduction in abundance) of six rockfish species (Sebastes) is of particular concern. Trade‐offs are inherent in this multispecies fishery because there is limited capacity to target species individually. From population models and catch of 34 stocks of bottom fish, we calculated the relation between harvest rate, long‐term yield (i.e., total weight of fish caught), profit, and depletion of each species. In our models, annual ecosystem‐wide yield from all 34 stocks was maximized with an overall 5.4% harvest rate, but profit was maximized at a 2.8% harvest rate. When we reduced harvest rates to the level (2.2% harvest rate) at which no stocks collapsed (<10% of unfished levels), biomass harvested was 76% of the maximum sustainable yield and profit 89% of maximum. A harvest rate under which no stocks fell below the biomass that produced maximum sustainable yield (1% harvest rate), resulted in 45% of potential yield and 67% of potential profit. Major reductions in catch in the late 1990s led to increase in the biomass of the most depleted stocks, but this rebuilding resulted in the loss of >30% of total sustainable yield, whereas yield lost from stock depletion was 3% of total sustainable yield. There are clear conservation benefits to lower harvest rates, but avoiding overfishing of all stocks in a multispecies fishery carries a substantial cost in terms of lost yield and profit.
Bitch, Bitch, Bitch: Personal Criticism, Feminist Theory, and Dog‐writing
Authors: Mchugh Susan
Published: March 2012

By the turn of the twenty‐first century, women writing about electing to share their lives with female canines directly confront a strange sort of backlash. Even as their extensions of the feminist forms of personal criticism contribute to significant developments in theories of sex, gender, and species, they become targets of criticism as “indulgent” for focusing on their dogs. Comparing these elements in and around popular memoirs like Caroline Knapp'sPack of Two: The Intricate Bond between People and Dogs(1998) and Deirdre McCloskey'sCrossing: A Memoir(1999), as well as academic studies like Alice Kuzniar'sMelancholia's Dog: Reflections on Our Animal Kinship(2006) and Donna Haraway'sWhen Species Meet(2007), this essay elaborates the ways in which living with and writing about female canine companions informs poststructuralist and feminist questions about the embodiment and performance of structures of authority, including those of academic writers, “dog‐mom” stereotypes, and reproductively silenced bodies. Situating these texts amid discussions of form in and around feminist/dog‐writing, I argue that together they move narrative beyond the abstract model of the lone “authoritative” human individual, reframing feminist politics as intra‐active, even trans‐species, from the ground up.
Effects of Long‐Term Simulated RPD Clasp Attachment/Detachment on Retention Loss and Wear for Two Clasp Types and Three Abutment Material Surfaces
Authors: Helal Mohamed A. , Baraka Osama A. , Sanad Mohamed E. , Ludwig Klaus , Kern Matthias
Published: March 2012

Purpose: The purpose of this in vitro study was to measure the loss of retention and wear of two clasp types (E‐circlet, back action) against three abutment materials (enamel, composite, CAD/CAM ceramic) after 16,000 simulated cycles of attachment‐detachment.

Materials and Methods: Forty‐eight models were constructed by placing either an upper first premolar or a metal die inside a metal rectangular block. Models were divided according to the abutment teeth into three groups. Group E consisted of 16 unrestored human premolars with sound enamel. Group R had 16 premolars recontoured buccally using composite resin. Group C had 16 metal dies (duplicated from a human premolar) covered by CAD/CAM all‐ceramic crowns. On the models, E‐circlet (E) and back‐action (B) clasps were constructed to engage the model's teeth. Withdrawal and insertion cycling of clasps was carried out for 16,000 cycles by using a chewing simulator. The retention force of each clasp was measured after cycling. An acrylic replica was made for each abutment retention surface before and after cycling. Each replica was examined by SEM, and the wear areas were measured. The data were analyzed statistically using one‐way ANOVA, two‐way ANOVA, and Mann‐Whitney tests.

Results: There was no significant retention loss after 16,000 cycles (p≥ 0.05) of both clasps (E, B) on the three abutment materials (E, R, C). The mean of wear areas in mm2 were 1.83 ± 0.36, 0.85 ± 0.66, 2.37 ± 1.88, 1.7 ± 1.11, 0.6 ± 0.2, and 0.06 ± 0 for EE, BE, ER, BR, EC, and BC, respectively. There were significant differences among the wear areas of the abutment surface of the six subgroups (p≤ 0.05).

Conclusion: The composite resin contoured surfaces showed more wear than the enamel and ceramic surfaces. E‐clasps caused more wear on the abutment materials than back‐action clasps.
Government‐wide Financial Statements and Credit Risk
Authors: JOHNSON CRAIG L. , KIOKO SHARON N. , HILDRETH W. BARTLEY
Published: March 2012

Now that state governments issue comprehensive annual financial reports in accordance with Statement No. 34 of the Governmental Accounting Standards Board, it is possible to generate a consistent and comprehensive set of government‐wide financial information. We use the information to develop financial ratios to benchmark government financial performance from information beyond the traditional general fund, and test the hypothesis that such information is incorporated into the assessment of credit risk. We provide an empirical analysis of the incorporation of government‐wide financial information into state government credit ratings, which provides a positive empirical test of the theory of certification and demonstrates how information from the government‐wide financial statements is infused into financial markets.
No Guaranties: The Decline of Municipal Bond Insurance
Authors: ELY TODD L.
Published: March 2012

The credit crisis that roiled the financial and housing markets in late 2007 and early 2008 resulted in well‐publicized budget challenges for state and local governments. Less visible has been a dramatic change in the bond insurance market, which alters how governments issue long‐term debt. Debt issuance data from Texas are used to model bond insurance premiums and examine utilization following the crisis. The results provide evidence that insurance premiums rose dramatically following the fiscal crisis, even when controlling for widening credit spreads and changes in the underlying credit quality of issuers.
Characteristics of Atrial Substrates for Atrial Tachyarrhythmias Induced in Aged and Hypercholesterolemic Rabbits
Authors: LEE KUN‐TAI , HSIEH CHANG‐CHAO , TSAI WEI‐CHUNG , TANG PAUL WEI‐HUA , LIU I‐HSIN , CHAI CHEE‐YIN , SHEU SHENG‐HSIUNG , LAI WEN‐TER
Published: March 2012

Background:

Old age and dyslipidemia increase the occurrence of atrial tachyarrhythmias (ATR). This study investigated the effect of age and hypercholesterolemia on the atrial substrates for ATR.

Methods:

Five 3‐year‐old rabbits fed standard chow were categorized into an old‐age group, five 3‐month‐old rabbits fed high cholesterol chow were used as a hypercholesterolemia group, and five 3‐month‐old rabbits fed standard chow were controls. Effective refractory period, atrial vulnerability to ATR, expressions of connexin40 (Cx40) and connexin43 (Cx43), phosphorylated c‐Jun N‐terminal Kinase (P‐JNK), and degree of fibrosis in the right (RA) and left (LA) atria were compared.

Results:

Old‐age and hypercholesterolemia rabbits were more vulnerable to ATR than the controls (18,628 ± 13,981 ms and 30,157 ± 39,548 ms vs 639 ± 325 ms, P < 0.05). Old‐age rabbits had significantly decreased Cx40 expression in both atria (3.9‐fold decrease in RA, P < 0.01 and 4.8‐fold in LA, P < 0.01) and significantly decreased Cx43 in RA (14‐fold, P < 0.01). Hypercholesterolemia rabbits had significantly decreased Cx40 expression in both atrial (18‐fold decrease in RA, P < 0.01 and 17‐fold in LA, P < 0.01) and significantly increased Cx43 expression in LA (five‐fold increase, P < 0.01). Hypercholesterolemia, but not old‐age rabbits, had greater expression of P‐JNK in both atria (1.8‐fold in RA and 2.3‐fold in LA, P < 0.01). There were no significant group differences in ERP or degree of atrial fibrosis in both atria.

Conclusions:

ATR is more easily induced in the atria of old‐age and hypercholesterolemia rabbits than younger rabbits with normal cholesterol levels. The age and hypercholesterolemia induced changes in gap junctions expression may have partially contributed to the higher atrial vulnerability to ATR. (PACE 2012;1–9)
Positron Annihilation Lifetime Studies of Nb‐Doped TiO2, SnO2, and ZrO2
Authors: Guagliardo Paul R. , Vance Eric R. , Zhang Zhaoming , Davis Joel , Williams Jim F. , Samarin Sergey N.
Published: March 2012

Positron annihilation lifetime spectroscopy (PALS) has indicated that Nb2O5‐doped TiO2 samples treated in either Ar or air at 1400°C for 48 h are both charge‐compensated by Ti vacancies, but with statistically significant differences between the results. A Ta2O5‐doped air‐sintered TiO2 sample also showed behavior similar to the Nb2O5‐doped air‐sintered TiO2. In addition, Nb2O5‐doped SnO2 samples sintered in air at 1400°C for 1 h showed evidence of Sn vacancy cluster formation, with no indications of Sn2+ compensation from ultraviolet irradiation studies. PALS studies of air‐sintered ZrO2 did not show any evidence of Zr vacancies after doping with Nb2O5.
Patterns of Breaks in Umbilical Cords by Different Mechanisms*
Authors: Evans Samantha R. , Mileusnic‐Polchan Darinka
Published: March 2012

Abstract:  Investigations of perinatal deaths often result in discrepancies between autopsy findings and witness accounts. The mechanism by which the umbilical cord is severed after delivery is a common quandary. Confirming or refuting the mother’s stated method frequently has significant investigative importance; however, a surprising paucity of data currently exists to allow an objective opinion about the likely mechanism. Ninety‐nine placentas with umbilical cords were examined. By random selection, each cord was severed by one of the following tools or mechanisms: knives, scissors, traction, or crush. Each break was examined and photographed, and a tissue section from the broken end examined microscopically. Differentiation of mechanism was best done grossly based on specific pattern recognition. Umbilical cords severed by blunt force have distinctly different morphology from those severed by sharp force. Even similar‐appearing sharp force transections frequently have mechanism‐specific distinctive patterns of injury.
Accuracy of Three Age Estimation Methods in Children by Measurements of Developing Teeth and Carpals and Epiphyses of the Ulna and Radius
Authors: Cameriere Roberto , De Luca Stefano , Biagi Roberto , Cingolani Mariano , Farronato Giampietro , Ferrante Luigi
Published: March 2012

Abstract:  The aim of this study was to compare the accuracy of three methods for age estimation in children: the measurements of open apices in tooth roots (T), the ratio between the total area of carpal bones and epiphyses of the ulna and radius (HW), and the combined method (THW). The sample consisted of 288 Caucasian Italian children (152 boys and 136 girls) aged between 5 and 15 years. Accuracy was determined as the difference between estimated age and chronological age, and accuracy was assessed by analyzing individuals’ orthopantomograms and hand‐wrist radiographs. Accuracies were 0.41 years for girls and 0.54 years for boys with the THW method; for the HW method, 1.00 years for girls and 0.92 years for boys; and for the T method, 0.62 years for girls and 0.71 years for boys. THW is the most accurate technique for age estimation in these children.
Peripheral autonomic nerves of human pineal organ terminate on vessels, their supposed role in the periodic secretion of pineal melatonin
Authors: Manzano e Silva Maria Joao , Singh Royana , Haldar Chandana , Vigh Béla , Szél Ágoston
Published: March 2012

Nonvisual pineal and retinal photoreceptors are synchronizing circadian and circannual periodicity to the environmental light periods in the function of various organs. Melatonin of the pineal organ is secreted at night and represents an important factor of this periodic regulation. Night illumination suppressing melatonin secretion may result in pathological events like breast and colorectal cancer. Experimental works demonstrated the role of autonomic nerves in the pineal melatonin secretion. It was supposed that mammalian pineals have lost their photoreceptor capacity that is present in submammalians, and sympathetic fibers would mediate light information from the retina to regulate melatonin secretion. Retinal afferentation may reach the organ by central nerve fibers via the pineal habenulae as well. In our earlier works we have found that the pineal organ developing from lobular evaginations of the epithalamus differs from peripheral endocrine glands and is composed of a retina‐like central nervous tissue that is comprised of cone‐like pinealocytes, secondary pineal neurons and glial cells. Their autonomic nerves in submammalians as well as in mammalian animals do not terminate on pineal cells, rather, they run in the meningeal septa among pineal lobules and form vasomotor nerve endings. Concerning the adult human pineal there are no detailed fine structural data about the termination of autonomic fibers, therefore, in the present work we investigated the ultrastructure of the human pineal peripheral autonomic nerve fibers. It was found, that similarly to other parts of the brain, autonomic nerves do not enter the human pineal nervous tissue itself but separated by glial limiting membranes take their course in the meningeal septa of the organ and terminate on vessels by vasomotor endings. We suppose that these autonomic vasomotor nerves serve the regulation of the pineal blood supply according to the circadian and circannual changes of the metabolic activity of the organ and support by this effect the secretion of pineal neurohormones including melatonin.
Genetic association analyses of PDYN polymorphisms with heroin and cocaine addiction
Authors: Clarke T.‐K. , Ambrose‐Lanci L. , Ferraro T. N. , Berrettini W. H. , Kampman K. M. , Dackis C. A. , Pettinati H. M. , O’Brien C. P. , Oslin D. W. , Lohoff F. W.
Published: March 2012

Genetic factors are believed to account for 30–50% of the risk for cocaine and heroin addiction. Dynorphin peptides, derived from the prodynorphin (PDYN) precursor, bind to opioid receptors, preferentially the kappa‐opioid receptor, and may mediate the aversive effects of drugs of abuse. Dynorphin peptides produce place aversion in animals and produce dysphoria in humans. Cocaine and heroin have both been shown to increase expression of PDYN in brain regions relevant for drug reward and use. Polymorphisms in PDYN are therefore hypothesized to increase risk for addiction to drugs of abuse. In this study, 3 polymorphisms in PDYN (rs1022563, rs910080 and rs1997794) were genotyped in opioid‐addicted [248 African Americans (AAs) and 1040 European Americans (EAs)], cocaine‐addicted (1248 AAs and 336 EAs) and control individuals (674 AAs and 656 EAs). Sex‐specific analyses were also performed as a previous study identified PDYN polymorphisms to be more significantly associated with female opioid addicts. We found rs1022563 to be significantly associated with opioid addiction in EAs [P = 0.03, odds ratio (OR) = 1.31; false discovery rate (FDR) corrected q‐value]; however, when we performed female‐specific association analyses, the OR increased from 1.31 to 1.51. Increased ORs were observed for rs910080 and rs199774 in female opioid addicts also in EAs. No statistically significant associations were observed with cocaine or opioid addiction in AAs. These data show that polymorphisms in PDYN are associated with opioid addiction in EAs and provide further evidence that these risk variants may be more relevant in females.
A Look Back at Merton Miller's “Financial Markets and Economic Growth”
Authors: Calomiris Charles W.
Published: March 2012

The author begins by agreeing with Miller's characterization of the fragility of U.S. banks and of the shortcomings of the Asian model of bank finance‐driven growth. The article also expresses “emphatic agreement” with Miller's arguments that the protection of banks through deposit insurance, regulatory forbearance, and other forms of “bailout” have created costly moral‐hazard problems that encourage excessive risk‐taking. And the author endorses, at least in principle, Miller's main argument that the development of capital markets that do not require the direct involvement of banks should make economies if not less prone to financial crises, then at least more resilient in recovering from them.

But having acknowledged the limitations of bank‐centered systems and the value of developing non‐bank alternatives for savers and corporate borrowers, the author goes on to point to the surprising durability of some banking systems outside the U.S.—notably Canada's, which has not experienced major problems since the 1830s. And even more important, the author views banks and capital markets not as “substitutes” for one another, but as mutually dependent “complements” whose interdependencies and interactions must be recognized by market participants and regulators alike.
Transparency in Bank Risk Modeling: A Solution to the Conundrum of Bank Regulation
Authors: Goldman David P.
Published: March 2012

After financial disasters, financial risk models are often blamed for failing to provide adequate warning. The author argues that, in many cases, the models provided accurate warnings but were ignored by market participants who did not like what they said.

The financial crisis of 2008–2009 was not the first time this has happened. The author describes similar but smaller debacles in 1994 and 1998 that had their roots in financial innovation that took place a decade earlier. In both cases, risk models warned that volatile securities would become impossible to hedge; but rather than exiting those positions as they should have done, some market participants simply ignored the flashing warning lights.

Some current financial risk models have proven to be quite robust. Large commercial banks have mined their internal data to create empirical models of default probability that forecast accurately out of sample. Default models based on contingent claims analysis have been available for years, including some that use continuously‐traded equity and equity options prices. Hybrid models that combine empirical data‐mining and forward‐looking market‐based signals have been shown to provide reliable early warning signals about corporate credit risk.

The author recommends making banks' data bases and risk models freely available to regulators, ratings agencies, and independent analysts. When provided with access to the findings of independent efforts to measure the riskiness of bank portfolios, public scrutiny and third‐party analysis would compel bank senior management to improve risk measurement and increase transparency. Banks would benefit by restoring market confidence in the quality of their books.

Making risk models transparent could also help break the present impasse between regulators and financial intermediaries. It may be possible for markets to establish a standard for credit risk that is more robust and more trustworthy than the ratings‐based system that fell into disrepute after the 2008 crisis. This would be preferable to the present thrust of bank regulation, which proposes to apply the severest standards to bank ownership of risk, and threatens to dampen economic growth.
Adjuvant adenoidectomy in persistent bilateral otitis media with effusion: hearing and revision surgery outcomes through 2 years in the TARGET randomised trial
Authors:   MRC Multicentre Otitis Media Study Group
Published: March 2012

Clin. Otolaryngol. 2012, 37, 107–116

Objectives:  To determine the adjuvant effects of adenoidectomy with short‐stay ventilation tubes to hearing and revision surgery in children over 3.5 years with persistent otitis media with effusion.

Design:  Randomised controlled three armed trial: observation, short‐stay ventilation tube or ventilation tubes with adjuvant adenoidectomy. Five follow‐up visits over 2 years.

Setting:  Eleven UK Otorhinolaryngology Departments.

Participants:  Children with bilateral otitis media with effusion and better ear hearing level (HL) ≥20 dB persistent for 3 months. Of the 425 eligible children, 376 (88%) accepted randomisation.

Main outcome measures:  Pure‐tone hearing thresholds, eligibility for and actual revision surgery rates, otoscopic sequelae and complications of adenoidectomy.

Results:  Loss to follow‐up at 3, 12 and 24 months was 2%, 6% and 5% respectively. Of the 376 randomised children, 253 (67%) had complete data for all five follow‐up visits. Adenoidectomy did not add to the benefit to hearing thresholds of ventilation tubes of 8.8 dB (CI: 7.1–10.5) averaged over 3–6 months postoperatively. Averaged over 12, 18 and 24 months, adenoidectomy provided 4.2 dB of benefit (CI: 2.6–5.7) whilst ventilation tubes gave no benefit. Standardised effect sizes through two years showed equal benefit from ventilation tubes (0.50 sd) and adenoidectomy (0.61 sd) which are additive (1.11 sd). Adenoidectomy halved the numbers meeting a 25 dB HL bilateral cut‐off for eligibility for repeat tube surgery from 31% to 14% at 12 months and from 33% to 15% at 18 months. The actual reduction in re‐insertion surgery (absolute risk difference) was 21%. In tubed ears, tympanosclerosis occurred in 27%, but otorrhoea in only <2% and permanent perforations in <1%. These events did not occur in control ears. In children that had adenoidectomy, one of 165 (0.6%) had haemorrhage that required return to theatre.

Conclusions:  Adjuvant adenoidectomy doubles benefit from short‐stay ventilation tubes by extending better hearing through the second year in children aged 3.25–6.75 years with persistent otitis media with effusion with at least a 20 dB HL in both ears. The duration of benefit of adenoidectomy is related to the duration of function of the type of the ventilation tubes used. Adenoidectomy also substantially reduces eligibility for revision surgery.
Effect of Substitution of Proline‐77 to Aspartate on the Light‐Driven Proton Release of Bacteriorhodopsin
Authors: Wang Yazhuo , Zhao Yingchun , Ming Ming , Wu Jia , Huang Weida , Ding Jiandong
Published: March 2012

Wild‐type bacteriorhodopsin (BR) and another retinal protein archaerhodopsin 4 (AR4) are both light‐driven proton pumps, but exhibit opposite temporal orders of proton release and uptake upon a flash illumination at neutral pH due to a higher pKa of proton release complex (PRC) in AR4. Since the 77th residue in the extracellular side is proline (P) in BR, but aspartic acid (D) in AR4, we have mutated P77 in BR by D in this study. The new point mutation was found to affect the kinetics of proton release and the pH dependence significantly. Upon a flash excitation, three components “fast proton release,”“proton uptake” and “slow proton release” were observed at neutral pH in P77D. The pKa of PRC in the M intermediate was increased from 5.6 in the wild‐type to 7.0, and became closer to that in AR4, which is 8.4. The coupling strength between D85 and PRC were also weakened, as expected. These data indicate that the 77th residue in AR4 greatly account for the difference between the two proton pumps.
Cardiac Shock Wave Therapy for Chronic Refractory Angina Pectoris. A Prospective Placebo‐Controlled Randomized Trial
Authors: Schmid Jean‐Paul , Capoferri Mauro , Wahl Andreas , Eshtehardi Parham , Hess Otto Martin
Published: March 2012

Background: Cardiac shock wave therapy (CSWT) delivered to the myocardium increases capillary density and regional myocardial blood flow in animal experiments. In addition, nonenzymatic nitric oxide production and the upregulation of vascular growth factor's mRNA by CSWT have been described. The aim of the study was therefore to test its potential to relieve symptoms in patients with chronic stable angina pectoris. Methods: Twenty‐one patients (mean age 68.2 ± 8.3 years, 19 males) with chronic refractory angina pectoris and evidence of inducible myocardial ischemia during MIBI‐SPECT imaging, were randomized into a treatment (n = 11) and a placebo arm (n = 10). The region of exercise‐induced ischemia was treated with echocardiographic guidance during nine sessions over a period of 3 months. One session of CSWT consisted of 200 shots/spot (9‐‐12 spots/session) with an energy intensity of 0.09 mJ/mm2. In the control group acoustic simulation was performed without energy application. Medication was kept unchanged during the whole treatment period. Results: In the treatment group, symptoms improved in 9/11 patients, and the ischemic threshold, determined by cardiopulmonary exercise stress testing, increased from 80 ± 28 to 95 ± 28 W (P= 0.036). In the placebo arm, only 2/10 patients reported an improvement and the ischemic threshold remained unchanged (98 ± 23 to 107 ± 23 W; P= 0.141). The items “physical functioning” (P= 0.043), “general health perception” (P= 0.046), and “vitality” (P= 0.035) of the SF‐36 questionnaire significantly improved in the treatment arm, whereas in the placebo arm, no significant change was noted. Neither arrhythmias, troponin rise nor complications were observed during treatment. Conclusions: This placebo controlled trial shows a significant improvement in symptoms, quality of life parameters and ischemic threshold during exercise in patients with chronic refractory angina pectoris treated with CSWT. Thus, CSWT represents a new option for the treatment of patients with refractory AP.
Do Sacral/Peripheral Lesions Contribute to Detrusor‐Sphincter Dyssynergia?
Authors: TAKAHASHI Osamu , SAKAKIBARA Ryuji , TSUNOYAMA Kuniko , TATENO Fuyuki , YANO Masashi , SUGIYAMA Megumi , UCHIYAMA Tomoyuki , YAMAMOTO Tatsuya , AWA Yusuke , YAMAGUCHI Chiharu , YAMANISHI Tomonori , KISHI Masahiko , TSUYUZAKI Yohei
Published: March 2012

Objectives: While detrusor‐sphincter dyssynergia (DSD) occurs in conjunction with lesions between the brainstem and the sacral cord, it is not well known whether sacral/peripheral lesions contribute to DSD. We studied the relationship between DSD and sacral/peripheral lesions.

Methods: One hundred and forty‐four patients with diverse neurologic etiologies underwent urodynamic study and analysis of motor unit potentials in the external sphincter muscles, 117 of whom were able to void during a urodynamic test. Sacral/peripheral lesion (SPL) is defined as neurogenic change in motor unit potentials. Detrusor overactivity (DO) is defined as involuntary detrusor contractions during the filling phase, which commonly occurs in lesions above the sacral cord. We considered DO as a putative indicator of supra‐sacral lesion.

Results: DSD was found in 44 (30.6%), SPL in 71 (49.3%), and DO in 83 (57.6%) of 144 patients, respectively. The incidence of DSD was the same in the SPL positive group (31%) and the SPL negative group (30.1%). By contrast, within the subgroup of patients without DO, the incidence of DSD was significantly more common in the SPL positive group (41.4%) than in the SPL negative group (25.0%) (P < 0.05). In 53 of the SPL positive group who were able to void, postvoid residual >100 mL was more common in patients with DSD (not statistically significant).

Conclusion: The results of the present study suggest that not only suprasacral pathology, but also sacral/peripheral lesions can produce DSD. In light of the previous reports, DSD might also result from partial lesions in peripheral branches of the sphincter circuit.
Attitudes on clinical research participation of community living elders in Korea
Authors: Shin Cheolmin , Park Moon Ho , Han Changsu , Patkar Ashwin A. , Ham Byung Joo , Kim Seung‐Hyun , Joe Sook‐Haeng , Pae Chi‐Un , Jung In‐Kwa
Published: March 2012

Introduction

The development of medical knowledge has involved increasing numbers of clinical studies, including trials of treatment modalities among elderly individuals. We evaluated knowledge about and attitudes on participation in various clinical trials among elderly individuals.

Methods

A semi‐structured survey was developed and distributed to community‐living elders who agreed to participate in the Ansan Geriatric Study. Survey items addressed (i) the process of acquiring consent, (ii) the advantages of participation in clinical trials, (iii) worries about participation, (iv) clinical field trials in which they would like to participate, and (v) reasons behind participation.

Results

A total of 361 individuals (158 women and 203 men, mean age 71.1 years) agreed to answer the survey about clinical trials. The reported advantages of participation in clinical trials were access to cost‐free medication or interventions (44.9%), prevention or early diagnosis of possible future diseases (23.8%), diagnostic and laboratory tests at no charge (14.7%), and contribution to human wellbeing (13.3) The reported disadvantages were the possibility of side‐effects from the new treatments (32.1%), giving blood for frequent laboratory tests (28.5%), concerns about intrusions on human dignity (9.9%), and possible leakage of personal identifying data (8.6%). An additional 10.8% saw no disadvantages. Subjects were interested in participating in clinical field trials for interventions or medication to treat metabolic syndrome and medical diseases (43.5%), Alzheimer's and Parkinson's diseases (11.1%), late‐life depression (2.5%). Although more than two‐thirds (77.3%) of the subjects believed that they should provide consent for themselves, some believed that their spouses (14.4%) or other family members (8.3%) should be able to receive the explanation of the clinical trial and sign the informed consent forms.

Discussion

We should consider the attitudes of elderly participants during the processes of explaining clinical trials and acquiring consent.
Some Topics in Recent Advances and Applications of Structural Impact Dynamics
Authors: Qiu X. M. , Yu T. X.
Published: March 2012

This paper reviews some topics related to the advances and applications of structural impact dynamics in recent years. Dynamic behavior of structural members including tubes, beams and plates under axial or transverse loading, and cellular materials and sandwich structures under impact or blast loading are summarized here. The research methodology involves experimental studies, theoretical modeling, as well as numerical simulations. However, as we mainly focus on the longer time dynamic responses of structures and cellular materials, studies of stress wave propagation and the material's strain-rate sensitivity are not included.
Characteristics of a Jet in the Vicinity of a Free Surface
Authors: Tian Jiahao , Roussinova Vesselina , Balachandar Ram
Published: March 2012

In this study, the characteristics of a round turbulent jet in the vicinity of a free surface are investigated. The jet issued from a nozzle located at a depth five times the nozzle diameter (d = 10 mm) below and parallel to the free surface. The jet exit velocity was 2.8 m/s and the resulting Reynolds number was 28,000. Instantaneous two-dimensional PIV measurements were obtained in the vertical central plane and in several horizontal planes at various distances (y/d = 0,±1,±2,±3± 4) from the axis of the nozzle. All fields-of-view were positioned at streamwise locations in the range of 28 < x/d < 62, where the jet interacts significantly with the free surface. The results reveal that the behavior of the surface jet is very similar to that of the free jet before it interacts with the free surface which occurs at about x/d = 30. Beyond this, the velocity normal to the free surface is diminished and those parallel to the free surface are enhanced in the region near the free surface. In the horizontal plane near the free surface (y/d = +4), the spreading of the surface jet is significantly greater than that of the free jet. The mean lateral flow in this region tends to be outward everywhere for the surface jet, while the opposite trend occurs in the free jet. Turbulence intensities in all three directions are reduced by the effect of the free surface confinement. Near the free surface, at y/d = +4, unlike the single peak streamwise turbulence intensity profile noticed in the case of the free jet, the off-axis double peaks reappear in the case of the surface jet. The magnitude of shear stress in the vertical central plane of the surface jet is smaller than that noticed in the free jet near the free surface. In identical horizontal planes, the shear stress (-uw¯) profiles are similar in both free jets and surface jets in regions where the interaction with the free surface is not significant (x/d ≈ 30). As the downstream distance increases near the free surface, the magnitudes of the shear stress profiles are larger compared to that of the free jet. An increase in the normal component of vorticity is observed in the horizontal planes near the free surface.
Experimental Evaluation of Cell Temperature Effects on Miniature, Air-Breathing PEM Fuel Cells
Authors: Williamson Zachary R. , Kim Daejoong , Chun Dae-Keun , Squibb Cody W. , Lee Tonghun
Published: March 2012

An experimental analysis of cell temperature effects on an air-breathing, PEM fuel cell is presented. The cell was tested in three active area sizes of 5 cm2, 10 cm2, and 25 cm2. The cell’s design minimized the influence of self-heating by using a large thermal body in its construction which conducted heat away from the active area. This allowed for the use of a heater and controller to test a constant cell temperature uninfluenced by current density. Polarization and electrochemical impedance spectroscopy testing showed that at higher current density, elevated temperature increased the buoyancy of the air around the cell which improved open cell performance. However, the opposite is true for lower current density as membrane dehydration becomes more prevalent at higher temperatures. Schlieren imaging, in conjunction with the polarization and EIS data, shows how heated and more buoyant air boosts cell performance. Infrared imaging identifies temperature gradients on the active surface which may hinder cell performance slightly.
Real-Time Hardware-in-the-Loop Tool for a Fuel Cell Hybrid System Emulator Test Rig
Authors: Caratozzolo Francesco , Ferrari Mario L. , Traverso Alberto , Massardo Aristide F.
Published: March 2012

The Thermochemical Power Group of the University of Genoa built a complete Hybrid System emulator test rig constituted by a 100 kW recuperated micro gas turbine, an anodic circuit (based on the coupling of a single stage ejector with a stainless steel vessel) and a cathodic modular volume (located between the recuperator outlet and combustor inlet). The system is sized to consider the coupling of the commercial micro turbine, operated at 62 kW load, and a planar Solid Oxide Fuel Cell (SOFC) to reach the overall electrical power output of 450 kW. The emulator test rig has been recently linked with a real-time model of the SOFC block. The model is used to simulate the complete thermodynamic and electrochemical behavior of a high temperature fuel cell based on solid oxide technology. The test rig coupled with the model generates a real-time hardware-in-the-loop (HIL) facility for hybrid systems emulation. The model is constituted by a SOFC module, an anodic circuit with an ejector, a cathodic loop with a blower (for the recirculation) and a turbine module. Temperature, pressure and air mass flow rate at recuperator outlet (downstream of the compressor) and rotational speed of the machine are inputs from the plant to the model. The turbine outlet temperature (TOT) calculated by the model is fed to the machine control system and the turbine electric load is moved to match the model TOT value. In this work different tests were carried out to characterize the interaction between the experimental plant and the real-time model; double step and double ramp tests of current and fuel characterized the dynamic response of the system. The mGT power control system proved to be fast enough, compared to the slow thermal response of the SOFC stack, and reliable. The hybrid systems was operated at 90% of nominal power with about 56% of electrical efficiency based on natural gas LHV.
Maximizing the Use of Platinum Catalyst by Ultrasonic Spray Application
Authors: Engle Robb
Published: March 2012

The following discusses the method and advantages of ultrasonic deposition of carbon-based platinum ink solution onto catalytic membranes in the manufacture of platinum-based fuel cells, doubling industry standard performances. Using patented ultrasonic atomization technology, conductive properties are compared to those of films created with hydraulic deposition and paste printing methods, using comprehensive analysis of morphology characteristics, deposition density, and distribution of platinum particles throughout the thickness and surface area of the coating. Results indicate significant increase in uniform distribution of platinum particles using the ultrasonic deposition method. Measured electrochemically active Pt surface area using ultrasonic atomization was recorded as high as 71% of the total Pt particle surface area.
A Parametric Study on Microfluidic Vanadium Fuel Cells
Authors: Lee Jin wook , Krishnamurthy Deepak , Hsiao Peter , Kjeang Erik
Published: March 2012

A parametric variation of microfluidic vanadium fuel cells is studied. The present membraneless and catalyst-free fuel cell consists of a microfluidic channel network with two porous carbon paper electrodes. An aqueous vanadium redox pair as reactants is supplied to the porous electrodes in a flow-through configuration. The dimensions of porous carbon electrodes and microchannels are varied from the baseline design to investigate their impacts on the fuel cell performance. In addition, a dependency on the number of electrical contacts is examined. Numerical simulations are performed in parallel with experimental activities to understand the coupled effects of mass transport, electrochemistry, electron conduction, and fluid velocity field. The simulation results are compared with the measured data from each cell design for verification. An optimal cell design is discussed based on the current study and future research opportunities were proposed.
Soft X-Ray Investigation on the Effect of Microstructure of PEMFC Porous Layers on Liquid Water Transport
Authors: Sasabe Takashi , Deevanhxay Phengxay , Tsushima Shohji , Hirai Shuichiro
Published: March 2012

In order to investigate the effect of microstructure of PEMFC porous layers on the liquid water behavior, liquid water accumulation and discharge behavior in the operating PEMFC was visualized by soft X-ray radiography. The utilization of low energy X-ray made it possible to detect the liquid water behavior in the porous layers with high temporal and spatial resolution, and the cross-sectional imaging can resolve the each components of the PEMFC. The visualization results showed that the liquid water distribution in the carbon paper and the carbon cloth GDL was completely different. The liquid water in the carbon cloth GDL concentrates at the weaves of fiber bundle and was effectively discharged to the channel. In addition, to investigate the effect of the network of pores in more detail, stereo imaging of the liquid water evaporation process from the carbon paper GDL was carried out. These visualization results suggested that the microstructure of the PEMFC porous layers strongly affect the liquid water behavior in the PEMFC.
Exploring Remedies for PH3 Poisoning of a Ni-YSZ Anode in Coal-Syngas Fuel
Authors: Xu Chunchuan , Zondlo John W. , Sabolsky Edward M.
Published: March 2012

Ni-YSZ cermet is commonly used as the anode of a solid oxide fuel cell (SOFC) because it has excellent electrochemical performance and is a cost effective anode material for coal-syngas fuel. However, coal-syngas contains trace contaminants, such as phosphine (PH3), hydrogen sulfur (H2S), arsine (AsH3) and stibine (SbH3), and these can cause degradation of the SOFC. Ni-YSZ anode-supported SOFCs were exposed to syngas and H2 fuel, while co-feeding PH3 and chlorine Cl2 impurities under a constant current load at 800°C. The cell degradation was postponed in syngas and highly mitigated in H2. In another test, a Ni-based filter was used to remove the PH3 impurity. The results show that the filter can effectively remove 20 ppm PH3 to a level which does not significantly degrade the SOFC over 400 h. The poisoning effects were evaluated by current-voltage scans and impedance spectroscopy, in addition to thermodynamic and chemical analyses. The post-mortem analyses of the cell and filter were performed by means of XRD and SEM/EDS.
Numerical Modeling of Solid Oxide Fuel Cell Operating on Biogas
Authors: Pakalapati Raju S. , Vural Yasemin , Celik Ismail , Xu Chunchuan , Zondlo John
Published: March 2012

Biogas can be used as a fuel in Solid Oxide Fuel Cells (SOFCs) for efficient power generation from a renewable source. However biogas is, in general, a complex fuel and much work is still needed to identify and remedy possible issues that might arise when used in SOFCs. In this study a SOFC operating on simulated biogas is modeled using an in-house computer code, namely DREAM-SOFC. The model solves for mass transfer, energy balance, electrochemistry and bulk chemical reactions inside the SOFC. Internal reforming of biogas is accounted for through both wet and dry reforming of methane. The model predictions of the cell performance curve are compared with the data from experiments also performed at West Virginia University for validation. The model is then used to predict the concentration distribution of species as well as the temperature distribution in the cell at different operating conditions.
Experimental and Numerical Evaluation of the By-Pass Flow in a Catalytic Plate Reactor for Hydrogen Production
Authors: Sigurdsson Haftor O. , Kær So̸ren K.
Published: March 2012

Numerical and experimental study is performed to evaluate the reactant by-pass flow in a catalytic plate reactor with a coated wire mesh catalyst for steam reforming of methane for hydrogen generation. By-pass of unconverted methane is evaluated under different wire mesh catalyst width to reactor duct width ratios, the results show that altering this ratio from 0.98 to 0.96 results in an increase in by-pass mass flow of 22%. Effect of catalytic wire mesh flow resistance on by-pass flow has also been investigated and results show increased by-pass flow as catalytic wire mesh flow resistance increases. The numerical results are in good agreement with experimental data. The study improves the understanding of the underlying transport phenomena in these reactors and shows that the flow maldistribution in a catalytic plate reactor using a coated wire mesh has to be considered.
CO2 Separation From Combined Cycles Using Molten Carbonate Fuel Cells
Authors: Manzolini G. , Campanari S. , Chiesa P. , Giannotti A. , Bedont P. , Parodi F.
Published: March 2012

This paper presents an analysis of advanced cycles with limited CO2 emissions based on the integration of Molten Carbonate Fuel Cells (MCFC) in natural gas fired combined cycles (NGCC) in order to efficiently capture CO2 from the exhaust of the gas turbine. In the proposed cycles, the gas turbine flue gases are used as cathode feeding for a MCFC, where CO2 is transferred from the cathode to anode side, concentrating the CO2 in the anode exhaust. At the anode side the MCFCs are fed with natural gas, processed by an external reformer which is thermally integrated within the FC module; the corresponding CO2 production is completely concentrated at the anode. The resulting anode exhaust stream is then sent to a CO2 removal section which is based on a cryogenic CO2 removal process, based on internal or external refrigeration cycles, cooling the exhaust stream in the heat recovery steam generator, and recycling residual fuel compounds to the power cycle. In all cases, a high purity CO2 stream is obtained after condensation of water and pumped in liquid form for subsequent storage. It is investigated the possibility to arrange the MCFC section with different configurations and operating parameters of the fuel cell modules, and the option to include two fuel cell modules in series connection, with intermediate cooling of the cathode stream, in order to enhance the plant CO2 separation effectiveness. The MCFC section behavior is simulated taking into account Ansaldo Fuel Cells experience and reference data, based on a dedicated simulation tool. Detailed energy and material balances of the most promising cycle configurations are presented; fuel cell and conventional components working parameters are described and discussed, carrying out a sensitivity analysis on the fuel cell CO2 utilization factor. The plant shows the potential to achieve a CO2 avoided fraction approaching 70–80%, depending on the CO2 concentration limit at cathode outlet, with an overall electric efficiency only 1–2% point lower than reference combined cycle. The plant power output increases by over 40%, thanks to the contribute of the MCFC section which acts as an active CO2 concentrator, giving a potentially relevant advantage with respect to competitive carbon capture technologies.
Modeling and Experiments of Voltage Transients of PEM Fuel Cells With the Dead-Ended Anode
Authors: Siegel Jason B. , Stefanopoulou Anna G. , Yesilyurt Serhat
Published: March 2012

The operation of PEM fuel cells (PEMFC) with dead-ended anode (DEA) leads to severe voltage transients due to accumulation of nitrogen, water vapor and liquid water in the anode channels and the gas diffusion layer (GDL). Accumulation of nitrogen causes a large voltage transient with a characteristic profile whereas the amount of water vapor in the anode is limited by the saturation pressure, and the liquid water takes up very small volume at the bottom of the anode channels in the case of downward orientation of the gravity. Here, we present a transient 1D along-the-channel model of PEMFCs operating with periodically-purged DEA channels. In the model, transport of species is modeled by the Maxwell-Stefan equations coupled with constraint equations for the cell voltage. A simple resistance model is used for the membrane to express the permeance of nitrogen and transport of water through the membrane. The model results agree very well with experimental results for the voltage transients of the PEMFC operating with DEA. In order to emphasize the effect of nitrogen accumulation in the anode, we present experimentally obtained cell voltage measurements during DEA transients, when the cathode is supplied with pure oxygen. In the absence of nitrogen in the cathode, voltage remained almost constant throughout the transient. Then, the model is used to determine the effect of oxygen-to-nitrogen feed ratio in the cathode on the voltage transient behavior for different load currents. Lastly, the model is used to show the effect of the small amount of leak from the anode exit on the voltage transient; even for leak rates as low as less than 10 ml/h, nitrogen accumulation in the anode channels is alleviated and the cell voltage remained almost constant throughout the transient.