bluuebunny/crossref_metadata_2025 huggingface dataset:
Perioperative care of a patient with Beare–Stevenson syndrome
Authors: UPMEYER SARA , BOTHWELL MARCELLA , TOBIAS JOSEPH D.
Published: September 2005

Beare–Stevenson syndrome is a craniofacial syndrome consisting of a specific pattern of craniosynostosis resulting in a cloverleaf skull deformity and hydrocephalus, down‐slanting palpebral fissures, proptosis, hypertelorism, strabismus, dysmorphic ears, choanal atresia, cleft palate, cutis gyratum, acanthosis nigricans, and abnormal genitalia. Its primary cause has been identified as a single amino acid substitution in fibroblast growth factor receptor 2. Of primary importance to the anesthesiologist are issues related to airway management resulting from midface hypoplasia, choanal atresia, and airway abnormalities (tracheal stenosis). Additional issues affecting airway management include associated cervical spine and foramen magnum abnormalities. The authors present their experience caring for a patient with Beare–Stevenson syndrome and discuss the anesthesia care of these patients.
Onset and duration of mivacurium‐induced neuromuscular blockade in children with Charcot–Marie–Tooth disease. A case series with five children
Authors: SCHMITT HUBERT J. , WICK STEFANIE , MÜNSTER TINO
Published: September 2005

Background:  The Charcot–Marie–Tooth (CMT) disorders are a group of hereditary motor and sensory neuropathies characterized clinically by peripheral muscle wasting and weakness. We hypothesized that unknown involvement of the muscle used for monitoring neuromuscular block may account for the conflicting reports about the effect of nondepolarizing neuromuscular agents in these patients. The aim of this study was to compare onset and recovery from mivacurium‐induced neuromuscular block on the adductor pollicis and orbicularis oculi muscles.

Methods:  We used mivacurium 0.2 mg·kg−1 in five children (aged 7–12 years) with CMT type I undergoing propofol–fentanyl–oxygen–air anesthesia for orthopedic surgery. Using acceleromyography, neuromuscular transmission was monitored in parallel in the eye and thumb muscles, and onset and duration times were recorded.

Results:  Following bolus administration of 0.2 mg·kg−1 of mivacurium the onset time ranged between 135 and 240 s and 75 and 165 s in the eye and in the thumb, respectively. The recovery time varied between 5.3 and 16 min and 6 and 31.3 min in the eye and in the thumb, respectively.

Conclusions:  In our small series of patients with CMT the clinical duration of mivacurium‐induced neuromuscular block was similar to data known from children without neuromuscular disease.
Postoperative shivering in children and causative factors
Authors: AKIN AYNUR , ESMAOGLU ALIYE , BOYACI ADEM
Published: September 2005

Background:  The aim of this study is to investigate the incidence of shivering in children and to reveal the causative factors as well as any possible clinical implications.

Methods:  This study was conducted on 1507 children who underwent surgery under general anesthesia. The patients were admitted to the postanesthesia care unit after the operation and their body temperatures measured from the tympanic membrane. The type of operation, operative time, method of anesthesia induction, age, and number of cases in which caudal block had been used were recorded.

Results:  Of the 1507 children, 53 (3.5%) experienced shivering. The use of intravenous induction agents, age older than 6 years, and prolonged duration of surgery were associated with shivering. The type of the operation and gender had no effect. The frequency of shivering was lower in children who underwent caudal block with a statistical significance (P < 0.05).

Conclusions:  The overall incidence of shivering in children is low (3.5%). Use of intravenous induction agents, age older than 6 years, and prolonged duration of surgery were associated with shivering; prophylaxis is not necessary in children, treatment is given only when shivering occurs.
Lifespan and stress resistance of Caenorhabditis elegans are increased by expression of glutathione transferases capable of metabolizing the lipid peroxidation product 4‐hydroxynonenal
Authors: Ayyadevara Srinivas , Engle Mark R. , Singh Sharda P. , Dandapat Abhijit , Lichti Cheryl F. , Beneš Helen , Shmookler Reis Robert J. , Liebau Eva , Zimniak Piotr
Published: September 2005

Caenorhabditis elegans expresses a glutathione transferase (GST) belonging to the Pi class, for which we propose the name CeGSTP2‐2. CeGSTP2‐2 (the product of the gst‐10 gene) has the ability to conjugate the lipid peroxidation product 4‐hydroxynonenal (4‐HNE). Transgenic C. elegans strains were generated in which the 5′‐flanking region and promoter of gst‐10 were placed upstream of gst‐10 and mGsta4 cDNAs, respectively. mGsta4 encodes the murine mGSTA4‐4, an enzyme with particularly high catalytic efficiency for 4‐HNE. The localization of both transgenes was similar to that of native CeGSTP2‐2. The 4‐HNE‐conjugating activity in worm lysates increased in the order: control < mGsta4 transgenic < gst‐10 transgenic; and the amount of 4‐HNE‐protein adducts decreased in the same order, indicating that the transgenic enzymes were active and effective in limiting electrophilic damage by 4‐HNE. Stress resistance and lifespan were measured in transgenic animals (five independent lines each) and were compared with two independent control lines. Resistance to paraquat, heat shock, ultraviolet irradiation and hydrogen peroxide was greater in transgenic strains. Median lifespan of mGsta4 and gst‐10 transgenic strains vs. control strains was increased by 13% and 22%, respectively. In addition to the cause–effect relationship between GST expression and lifespan observed in the transgenic lines, correlative evidence was also obtained in a series of congenic lines of C. elegans in which lifespan paralleled the 4‐HNE‐conjugating activity in whole‐animal lysates. We conclude that electrophilic damage by 4‐HNE may contribute to organismal aging.
Indigenous Population Growth in the Lowland Neotropics: Social Science Insights for Biodiversity Conservation
Authors: McSWEENEY KENDRA
Published: September 2005

Abstract:  Conservationists have expressed concern over the possibility that growth of indigenous populations in Latin America's tropical lowlands may compromise local biodiversity and undermine alliances between natives and conservationists. Through a review of demographic data and theory, I show how social science insights can offer conservationists a much‐needed new perspective on the issue of indigenous population growth. For example, recent surveys offer a baseline of actual demographic trends to replace the suppositions and impressions that have dominated conservationists' discussions to date. They show that Neotropical indigenous populations are growing rapidly: fertility is high, infant mortality rates are declining, and populations are correspondingly young. New insights from anthropological demography highlight, in turn, how indigenous population growth need not inevitably lead to resource degradation. Rather, indigenous peoples' demographic resurgence can be tied in unexpected ways to the improved defense of their homelands and the management of associated resources. Although much future research is needed to establish the strengths of these links in particular landscapes, some initial recommendations for ongoing conservation initiatives in native homelands go beyond the standard prescription (fertility reduction programs) to include monitoring of target populations' vital rates, closer attention to women's indirect contributions to conservation, and a renewed focus on the enforcement of indigenous territorial rights.
Reproductive Investment of a Lacertid Lizard in Fragmented Habitat
Authors: DÍAZ JOSÉ A. , PÉREZ‐TRIS JAVIER , TELLERÍA JOSÉ L. , CARBONELL ROBERTO , SANTOS TOMÁS
Published: September 2005

Abstract:  We studied the effect of habitat fragmentation on female reproductive investment in a widespread lacertid lizard ( Psammodromus algirus) in a mixed‐forest archipelago of deciduous and evergreen oak woods in northern Spain. We captured gravid females in fragments (≤10 ha) and forests (≥ 200 ha) and brought them to the laboratory, where they laid their eggs. We incubated the eggs and released the first cohort of juveniles into the wild to monitor their survival. Females from fragments produced a smaller clutch mass and laid fewer eggs (relative to mean egg mass) than females of similar body size from forests. Lizards did not trade larger clutches for larger offspring, however, because females from fragments did not lay larger eggs (relative to their number) than females from forests. Among the first cohort of juveniles, larger egg mass and body size increased the probability of recapture the next year. Thus, fragmentation decreased the relative fecundity of lizards without increasing the quality of their offspring. Reduced energy availability, increased predation risk, and demographic stochasticity could decrease the fitness of lizards in fragmented habitats, which could contribute to the regional scarcity of this species in agricultural areas sprinkled with small patches of otherwise suitable forest. Our results show that predictable reduction of reproductive output with decreasing size of habitat patches can be added to the already known processes that cause inverse density dependence at low population numbers.
Valdecoxib for Treatment of a Single, Acute, Moderate to Severe Migraine Headache
Authors: Kudrow David , Thomas H. Mikel , Ruoff Gary , Ishkanian Gary , Sands George , Le Vu H. , Brown Mark T.
Published: September 2005

Objective.—To evaluate the analgesic efficacy and safety of a single 20‐ or 40‐mg dose of valdecoxib compared with placebo in treatment of a single, acute, moderate or severe migraine headache, with or without aura.

Background.—Valdecoxib, an oral COX‐2 specific inhibitor, is indicated for relief of the signs and symptoms of rheumatoid arthritis and osteoarthritis and treatment of primary dysmenorrhea. This study assessed the optimal dose of valdecoxib for treatment of a single, acute, moderate to severe migraine headache.

Methods.—This was a double‐blind, randomized, placebo‐ and active‐controlled, multicenter, single‐dose (primary end point) and multiple‐dose (secondary end point), 56‐day study of valdecoxib in the treatment of a single, acute, moderate or severe migraine headache, with or without aura. Migraine headaches were diagnosed according to International Headache Society (IHS) criteria. The primary efficacy end point was headache response (defined as reduction of headache pain intensity from moderate or severe to mild or none) at 2 hours postdose. Patients assessed their headache pain intensity and presence or absence of migraine‐associated nausea, vomiting, phonophobia, and photophobia at intervals from 0 to 24 hours postdose. Sumatriptan 50 mg (encapsulated, in standard method, to maintain blinding) was included as a positive control for assay sensitivity. No statistical comparisons were performed between active treatment arms (valdecoxib 20 mg, valdecoxib 40 mg, and sumatriptan 50 mg). Adverse events and safety parameters were monitored throughout the study.

Results.—In the intent‐to‐treat population of 570 patients (135 valdecoxib 20 mg, 151 valdecoxib 40 mg, 143 sumatriptan, and 141 placebo), no significant differences in baseline demographics among treatment groups were observed. The headache response rate with valdecoxib 40 mg and sumatriptan 50 mg was significantly greater than that with placebo at all time points from 2 to 24 hours postdose. With valdecoxib 20 mg, headache response rate was significantly greater than placebo from 2 to 4 hours. Significantly fewer patients treated with valdecoxib 40 mg, compared with placebo, experienced nausea, vomiting, and phonophobia at 2 hours postdose.

Conclusions.—A single 40‐mg dose of valdecoxib is effective and well tolerated in treatment of migraine headache pain and associated symptoms.
Patterns and Predictors of Prescription Medication Use in the Management of Headache: Findings From the 2000 Medical Expenditure Panel Survey
Authors: Devine Joshua W. , Farley Joel F. , Hadsall Ronald S.
Published: September 2005

Objective.—The primary objectives were to examine national trends of prescription medication use for headache and explore patterns of variation in the use of these medications across social and demographic levels.

Background.—Despite widespread use of prescription medication for management of headache, little is known about utilization patterns or patient characteristics associated with receiving this type of treatment.

Methods.—This study conducted a secondary analysis of data obtained during the 2000 Medical Expenditure Panel Survey, a representative survey of the U.S. noninstitutionalized population. Weighted descriptive statistics and logistic regression models were used to evaluate patterns and rates of overall prescription medication use in patients reporting headache as a household condition.

Results.—An estimated 9.7 million people 18 years or older reported suffering from headache in 2000. Of these, 46% reported using at least one medication for the treatment of headache. Migraine‐specific abortive medication (ie, selective serotonin receptor agonists and ergotamine derivatives) was the most frequently reported medication class, used by 36% of participants. Opiate analgesics and butalbital‐containing products also experienced extensive prescribing reported by 22% and 17% of survey respondents, respectively. After adjustment for covariates, wide variation in the use of prescription medication was observed across sociodemographic characteristics including age, ethnicity, and insurance status.

Conclusion.—The observed variation in prescription medication use by drug class and sociodemographic characteristics suggests strategies are needed for improving current prescribing patterns in this patient population.
Assessing Cortical Excitability in Migraine: Reliability of Magnetic Suppression of Perceptual Accuracy Technique Over Time
Authors: Custers Anouk , Mulleners Wim M. , Chronicle Edward P.
Published: September 2005

Objectives.—To examine test–retest reliability of magnetic suppression of perceptual accuracy (MSPA) prior to its use as a marker of cortical excitability in a trial of migraine prophylactic agents.

Background.—MSPA is a relatively novel avenue of research in headache, providing an opportunity to study cortical responsiveness objectively and noninvasively. However, little is known about the reliability of magnetic stimulation protocols such as MSPA in longitudinal research designs.

Methods.—We tested 10 healthy headache‐free volunteers who had no family history of migraine. In 54 trials, they were briefly presented different three‐letter combinations, flashed on a computer screen for 24 ms (target). After a brief interval, each target was followed by a single magnetic pulse through a 90‐mm circular coil centered 7 cm above inion in the midline. The interval between target and magnetic pulse was systematically varied. Volunteers were requested to report as many letters as they had possibly identified. After 2 weeks, all volunteers were retested using identical methods.

Results.—MSPA performance is expressed as a profile of response accuracy (ie, percentage of correctly identified letters) across target‐pulse intervals. Profiles were characteristic of normal headache‐free subjects at the first test. Analysis of variance revealed no significant difference in profiles between test and retest (F= 2.05; P= .136): the retest profiles are almost coincidental with the test profiles.

Conclusions.—MSPA is a safe and objective measure of cortical excitability, which is reliable over time. MSPA, therefore, shows excellent promise as a biological marker of cortical response in trials of migraine prophylactics.
Changes in Cortical Processing of Pain in Chronic Migraine
Authors: De Tommaso Marina , Losito Luciana , Difruscolo Olimpia , Libro Giuseppe , Guido Marco , Livrea Paolo
Published: September 2005

Objective.—The aim of this study was to perform a topographic and dipolar analysis of nociceptive‐evoked responses obtained by laser stimulus under basal conditions in a cohort of chronic migraine (CM) patients, compared with migraine without aura (MWA) patients and noncraniofacial pain controls.

Background.—An increased activation of cortical areas devoted to the emotional and attentive components of pain was previously found during the course of the migraine attack; it was more pronounced in patients reporting higher frequency of migraine.

Methods.—Twenty‐six outpatients were enrolled in the study; 16 fulfilled the criteria of CM, and 10 were affected by MWA. Fifteen noncraniofacial pain subjects were also selected. The pain stimulus was a CO2 laser pulses. The right‐supraorbital zone was stimulated. Source localization analysis was performed on the most prominent laser‐evoked potentials (LEPs) peak (P2) for each data set. The anatomical locations of the P2 sources were projected onto a standard normalized 3D MRI model.

Results.—The CM group differed significantly from both MWA patients and controls for the x coordinate and from controls for the z coordinates. The P2 dipole localized in the rostral cingulate cortex in CM patients, lying in a more posterior location within the anterior cingulate cortex (ACC) in both controls and MWA patients. The x coordinate of the P2 dipole, expressing the postero‐anterior location, was significantly correlated with frequency of headache.

Conclusions.—CM seems to be characterized by a distinctive pattern of cortical elaboration of pain, with a prevalent activation of the rostral portion of the ACC: our results suggest that this may be a predisposing factor to migraine chronicity.
Spinal Manipulative Therapy in the Management of Cervicogenic Headache
Authors: Fernández‐de‐las‐Peñas Cesar , Alonso‐Blanco Cristina , Cuadrado Maria Luz , Pareja Juan A.
Published: September 2005

Patients suffering from cervicogenic headache (CeH) are commonly treated with spinal manipulative therapy. We have analyzed the quality and the outcomes of published, randomized, controlled trials assessing the effectiveness of spinal manipulation in CeH. Among 121 relevant articles, only two met all the inclusion criteria. Methodological quality scores were 8/10 and 7/10 points. Only one of the trials made use of a headache diary. Both the trials reported positive (+) results on headache intensity, headache duration, and medication intake, so that spinal manipulative therapy obtained strong evidence of effectiveness (level 1) with regard to these outcomes. Conversely, spinal manipulation obtained no more than limited evidence (level 3) in reducing headache frequency, as it was analyzed only in one study with positive (+) results. A greater number of well‐designed, randomized, controlled trials are required to confirm or refute the effectiveness of spinal manipulation in the management of CeH.
Migraine, Celiac Disease, and Cerebral Calcifications: A New Case
Authors: D'Amico Domenico , Rigamonti Andrea , Spina Luisa , Bianchi‐Marzoli Stefania , Vecchi Maurizio , Bussone Gennaro
Published: September 2005

Celiac disease is sometimes associated with neurological complications. Only one case of celiac disease associated with migraine and cerebral calcifications has been reported. We present a patient with migraine (with and without aura) in whom neuroimaging revealed cerebral calcifications in the occipital and parietal regions bilaterally. Visual examination showed bilateral double scotoma, and further investigations revealed celiac disease. Migraine may on occasion be a sentinel symptom of mild celiac disease.
Nursing Home Practitioner Survey of Diagnostic Criteria for Urinary Tract Infections
Authors: Juthani‐Mehta Manisha , Drickamer Margaret A. , Towle Virginia , Zhang Ying , Tinetti Mary E. , Quagliarello Vincent J.
Published: September 2005

Objectives: To identify clinical and laboratory criteria used by nursing home practitioners for diagnosis and treatment of urinary tract infections (UTIs) in nursing home residents. To determine practitioner knowledge of the most commonly used consensus criteria (i.e., McGeer criteria) for UTIs.

Design: Self‐administered survey.

Setting: Three New Haven–area nursing homes.

Participants: Physicians (n=25), physician assistants (PAs, n=3), directors/assistant directors of nursing (n=8), charge nurses (n=37), and infection control practitioners (n=3).

Measurements: Open‐ and closed‐ended questions.

Results: Nineteen physicians, three PAs, and 41 nurses completed 63 of 76 (83%) surveys. The five most commonly reported triggers for suspecting UTI in noncatheterized residents were change in mental status (57/63, 90%), fever (48/63, 76%), change in voiding pattern (44/63, 70%), dysuria (41/63, 65%), and change in character of urine (37/63, 59%). Asked to identify their first diagnostic step in the evaluation of UTIs, 48% (30/63) said urinary dipstick analysis, and 40% (25/63) said urinalysis and urine culture. Fourteen of 22 (64%) physicians and PAs versus 40 of 40 (100%) nurses were aware of the McGeer criteria for noncatheterized patients (P<.001); 12 of 22 (55%) physicians and PAs versus 38 of 39 (97%) nurses used them in clinical practice (P<.001).

Conclusion: Although surveillance and treatment consensus criteria have been developed, there are no universally accepted diagnostic criteria. This survey demonstrated a distinction between surveillance criteria and criteria practitioners used in clinical practice. Prospective data are needed to develop evidence‐based clinical and laboratory criteria of UTIs in nursing home residents that can be used to identify prospectively tested treatment and prevention strategies.
Pacemaker‐Like Syndrome Complicating Slow Pathway Ablation for AV Nodal Reentrant Tachycardia
Authors: TOAL SATISH , CHAUHAN VIJAY S.
Published: September 2005

This case report describes pacemaker‐like syndrome after successful slow pathway ablation for atrioventricular (AV) nodal reentrant tachycardia due to recurrence of single AV nodal echo beats during sinus rhythm. The resultant AV dyssynchrony was responsible for the symptom complex. Following ablation of retrograde ventriculoatrial conduction, the AV nodal echo beats were eliminated and the pacemaker‐like syndrome resolved.
Tilt Testing: Is It Necessary in All Patients with Suspected Vaso‐Vagal Syncope?
Authors: KULAKOWSKI PIOTR , PIOTROWSKA DOROTA , KONOFOLSKA AGNIESZKA
Published: September 2005

Background: Head‐up tilt testing (HUTT) is a well‐established diagnostic tool in patients with suspected vaso‐vagal syncope (VVS). However, it is time‐consuming and requires special equipment. Thus, identification of simple parameters which could predict the outcome of HUTT could simplify diagnostic steps by obviating the need for HUTT.

Aim: To assess which symptoms associated with spontaneous syncope or other details from medical history can predict HUTT results.

Methods: The study group consisted of 202 unselected patients (69 males, mean age 43 ± 20 years) who were admitted to our syncope unit for HUTT due to suspected VVS. They filled in a detailed questionnaire including 34 standard questions concerning medical history as well as circumstances and symptoms associated with syncopal episodes. Patients were tilted to 70° for 45 minutes or the test was stopped earlier if syncope occurred. A stepwise multiple logistic regression was performed in order to assess which parameters independently predicted the results of HUTT. A point‐score was developed by assigning ±1, ±2, or ±3 points to each of the factors based on the relative magnitude of the estimated regression coefficient. The points were then summed and a diagnostic threshold chosen using plots of sensitivity and specificity curves.

Results: Syncope was induced by HUTT in 67 (33%) patients. In the whole study group, a point‐score identified patients with positive HUTT with a sensitivity of 87.9%, and specificity of 36.3%. When the analysis was confined to the subgroup with >4 syncopal episodes in the past, the sensitivity of a point‐score was 94.4%, and specificity—60%, and in the subgroup with >2 syncopal episodes occurring within 1 month preceding HUTT, sensitivity values reached 88.2% at the specificity level of 90.9%.

Conclusions: In patients with frequent syncopal episodes, especially clustered shortly before performing HUTT, in whom symptoms are very suggestive of VVS, a simple point‐score system based on medical history accurately predicts HUTT results. Thus, HUTT may not be necessary for establishing diagnosis in this group of patients.
Electrophysiologic Effects of Carvedilol: Is Carvedilol an Antiarrhythmic Agent?
Authors: EL‐SHERIF NABIL , TURITTO GIOIA
Published: September 2005

The cardiovascular drug carvedilol is characterized by multiple pharmacological actions, which translate into a wide‐spectrum therapeutic potential. Its major molecular targets are membrane adrenoceptors, ion channels, and reactive oxygen species. Carvedilol's favorable hemodynamic effects are due to the fact that the drug competitively blocks β1‐, β2‐, and α1‐ adrenoceptors. Several additional properties have been documented and may be clinically important, including antioxidant, antiproliferative/antiatherogenic, anti‐ischemic, and antihypertrophic effects. The antiarrhythmic action of carvedilol may be related to a combination of its β‐blocking effects with its modulating effects on a variety of ion channels and currents. Several studies suggest that the drug may be useful in reducing cardiac death in high‐risk patients with prior myocardial infarction and/or heart failure, as well as for primary and secondary prevention of atrial fibrillation. This article will review experimental data available on the electrophysiologic properties of carvedilol, with a focus on their clinical relevance.
Percutaneous Extraction of a Fractured Permanent Pacemaker Lead with No Free End
Authors: SOCHMAN JAN , PEREGRIN JAN H. , BYTESNIK JAN
Published: September 2005

From various points of view abandoned or displaced permanent pacemaker leads should be extracted in indicated cases using a broad spectrum of catheter‐based techniques. We describe a relatively easy extraction procedure of almost the whole pacemaker lead, which broke near the pulse generator and migrated into right‐heart chambers; so both ends were indwelling. The described procedure was undertaken using a simple homemade nitinol‐based extractor.
Documentation of Acute Increase in Ventricular Capture Threshold After Direct Current Cardioversion with AutoCapture™ Threshold Record
Authors: KURISU SATOSHI , INOUE ICHIRO , KAWAGOE TAKUJI , ISHIHARA MASAHARU , SHIMATANI YUJI , MITSUBA NAOYA , HATA TAKAKI , NAKAMA YASUHARU , KIJIMA YASUFUMI , KISAKA TOMOHIKO
Published: September 2005

This report describes acute and persistent increase in ventricular capture threshold after direct current cardioversion by using AutoCapture™ threshold record. Careful follow‐up is required to be sure that the system continues to function according to its design specifications.
Inappropriate Detection and Therapy from an Implantable Cardioverter Defibrillator Due to Atrial Undersensing
Authors: PARASKEVAIDIS STELIOS , POLYMEROPOULOS KOSTAS , VASSILIKOS VASSILIS , LOURIDAS GEORGE
Published: September 2005

We present a case of inappropriate detection and therapy in a patient with an implantable cardioverter defibrillator. The device interpreted a supraventricular tachycardia as ventricular tachycardia due to unsensed P waves as a result of a relatively high level of atrial sensitivity setting. Subsequently, inappropriate therapy was delivered. The problem was resolved by decreasing the atrial sensitivity value.
Tailored Residual Stresses in High Reliability Alumina‐Mullite Ceramic Laminates
Authors: Sglavo Vincenzo M. , Paternoster Massimo , Bertoldi Massimo
Published: September 2005

A design and processing approach to fabricate ceramic laminates with high mechanical reliability, i.e., high failure resistance, limited strength scatter, and increased damage tolerance is presented in this paper. Different ceramic layers are stacked together to develop a specific residual stress profile after sintering. By changing the composition of the laminae and the composite architecture it is possible to produce a material with predefined failure stress which can be evaluated from the fracture toughness curve correlated to the residual stresses. In addition, by tailoring the fracture toughness curve, surface defects can be forced to grow in a stable way before reaching the critical condition, thus obtaining a unique‐value strength ceramic material. Laminates composed of alumina/mullite composite layers are designed and created in this work by the implementation of the proposed approach. The material obtained shows a “constant” strength of 456 MPa (standard deviation <7%) even when large surface damage is produced by Vickers indentation.
Ferroelectric and Dielectric Properties of Pb(Mg1/3Ta2/3)0.7Ti0.3O3 Thin Films Derived from RF Magnetron Sputtering
Authors: Li Fang , Xue Junmin , Wang John
Published: September 2005

Pb(Mg1/3Ta2/3)0.7Ti0.3O3 thin films of single perovskite phase were successfully synthesized by using the RF sputtering deposition technique, followed by post‐thermal annealing. While the perovskite structure of Pb(Mg1/3Ta2/3)0.7Ti0.3O3 is rather unstable, phase evolution in the thin films was manipulated by controlling both working pressure during the sputtering process and post‐thermal annealing temperature. The desirable perovskite phase was promoted by increasing the working pressure in the range of 10–25 mTorr, followed by thermal annealing at 600°C. The ferroelectric, dielectric, and polarization behaviors of Pb(Mg1/3Ta2/3)0.7Ti0.3O3 films were characterized over a wide range of frequencies. They are strongly affected by the film thickness, where the relative permittivity and remanent polarization increase, while the coercive field decreases with increasing film thickness in the range of 115–360 nm.
Leaching of Lead and Connectivity of Plumbate Networks in Lead Silicate Glasses
Authors: Mizuno Megumi , Takahashi Masahide , Takaishi Taigo , Yoko Toshinobu
Published: September 2005

The formation of a plumbate network in binary lead silicate glasses was examined based on the leaching behavior of Pb2+ in lead silicate glasses over a wide composition region. The effective diffusion coefficient of Pb2+ at 40°C was on the order of 10−17 m2/s for PbO<35 mol% glasses, and increased three orders of magnitude for 35–50 mol% PbO contents. Such a steep composition dependence is considered to be because of changes in the medium or longer range structure. That is, it is proposed that the plumbate network forms a percolative 3D network in the composition region to form diffusion paths for the lead ions. In addition, the present results indicate that the lead ion exists as a network former over the entire glass forming composition range of the binary silicate glasses.
Processing, Microstructure, and Properties of Laminated Silicon Nitride Stacks
Authors: Bitterlich Bernd , Heinrich Jürgen G.
Published: September 2005

By lamination of silicon nitride tapes, components with complex geometries can be produced. Unstructured tapes can be laminated by common thermal compression. Structured tapes, however, have to be joined by pressureless processes using e.g. pastes as lamination aids because deformation of the structures would occur. These pastes usually contain a binder for maintaining the mechanical contact between the tapes during processing. To prevent the high mass loss of typical organic binders during burnout, pre‐ceramic polymers were used in this work. These ceramic precursors convert partly into an inorganic material during heat treatment with a significant reduced mass loss compared with common organic binders. Thus, the porosity in the interlayer of a laminated stack is strongly decreased, which should be favorable for the mechanical and thermal properties. This work discusses the resulting microstructure, strength, and thermal diffusivity data of stacks laminated with pastes containing various precursor contents. These results are compared with those obtained by samples prepared by compression of green tapes. It is found that except for some large pores, the microstructure of the precursor‐derived interlayers is qualitatively the same as in the tape material. For stacks made by both lamination methods, strength measurements reveal that the properties parallel and perpendicular to the layers are different. It is shown that the same strength level can be obtained both by using the pressureless route and by the compression method. Unlike the strength, the thermal conductivity does not change with the direction of measurement.
Extension of Master Sintering Curve Theory to Organic Decomposition
Authors: DiAntonio Christopher B. , Ewsuk Kevin G. , Bencoe Denise
Published: September 2005

The ability to predict and control organic decomposition of a material under arbitrary thermal treatments is one of the main objectives of thermogravimetric studies. The development of this ability provides significant potential to ensure reliability and reproducibility for a given processing method and can be used in planning optimized thermal treatment strategies. Based on this report, the master sintering curve theory has been successfully extended to similar kinetically controlled phenomena. The theory has been applied to organic decomposition reaction kinetics to develop a master organic decomposition curve. The fundamental kinetics are assumed to be governed by an Arrhenius‐type reaction rate, making master sintering and decomposition curves analogous to one another. The formulation and construction of a master decomposition curve are given in this paper. Simultaneous thermogravimetric and differential thermal analysis of a low‐temperature co‐fire glass/ceramic dielectric tape (Dupont 951 Green TapeTM) is analyzed and used to demonstrate this new concept. The results reveal two independent organic decomposition reactions, the first occurring at ≈245°C and the second at ≈365°C. The analysis is used to produce a master decomposition curve and to calculate the activation energy for these reactions, at 86±6 and 142±4 kJ/mol, respectively. In addition, the weight loss of product and the rate of decomposition can be predicted under varying thermal paths (time–temperature trajectories) following a minimal set of preliminary experiments.
Ferroelastic Fatigue of a Soft PZT Ceramic
Authors: Jones Jacob L. , Salz Christopher R. J. , Hoffman Mark
Published: September 2005

The performance and expected lifetime of piezoelectric ceramic components are ultimately defined by bulk material fatigue processes. In this work, strain accumulation of a ferroelectric/ferroelastic ceramic lead zirconate titanate is characterized under mechanical cycling using four‐point bend bar geometry. Strain accumulation occurs at a higher rate than in creep alone, indicating that the processes are fatigue related, and it is confirmed by X‐ray diffraction that the accumulated strain is contributed under both cyclic tensile and compressive stress by domain switching. The relative ranking of measured mechanical strains is nearly the same as the theoretical saturated domain‐switching strains.
Temperature Effect on Hydrogen Generation by the Reaction of γ‐Al2O3‐Modified Al Powder with Distilled Water
Authors: Deng Zhen‐Yan , Liu Yu‐Fu , Tanaka Yoshihisa , Zhang Hong‐Wang , Ye Jinhua , Kagawa Yutaka
Published: September 2005

The effect of temperature on the reaction of γ‐Al2O3‐modified Al powders with distilled water was investigated. It was found that by increasing the temperature up to 40°C, the hydrogen generation speed can be enhanced one to two orders of magnitude relative to that at room temperature (18°C). X‐ray analyses and transmission electron microscopy observations revealed that the reaction by‐product at 40°C is bayerite (Al(OH)3), which is chemically neutral. The present results imply that slightly increasing the temperature is an effective way to get the target hydrogen generation speed.
Two mouse mutations mapped to chromosome 11 with differing morphologies but similar progressive inflammatory alopecia
Authors: Wood Geoffrey A. , Flenniken Ann , Osborne Lucy , Fleming Craig , Vukobradovic Igor , Morikawa Lily , Xu Qiang , Porter Rebecca , Adamson S. Lee , Rossant Janet , McKerlie Colin
Published: September 2005

Abstract:  Alopecia is a common dermatological condition in humans and other mammals. Here, we present two similar but histologically distinct mouse models of scarring alopecia. Both mutant lines were generated using random genome‐wide N‐ethyl‐N‐nitrosourea mutagenesis, and both harbor dominant mutations on chromosome 11. In both mutants, there is an early onset of alopecia that progresses to nearly complete pelage hair loss in both males and females by 20 weeks of age. Histologically, there is an increased dermal cellularity due to inflammatory cell infiltration at 7–10 days of age. By 3 weeks of age, the epidermis is acanthotic and the dermis is approximately twice as thick as in control mice due to a substantial, mostly mononuclear, inflammatory cell infiltrate. This infiltrate becomes more perifollicular by 4–5 weeks of age but is localized differently in the two mutants. In alopecia 1 (Alo‐1), the perifollicular infiltrate is confined to the portion of the follicle within the dermis, whereas in Alo‐2, the infiltrate extends the full length of the follicle. Expression of major histocompatibility complex (MHC) class I on the follicular epithelium in the two mutants is much greater than that in non‐mutants. Furthermore, MHC class I expression is localized differently in the two mutant lines and mirrors the pattern of the inflammatory infiltrate. Despite these differences, the clinical progression of alopecia is identical in both mutants. The early onset of the disease, predictable progression, and differences in inflammatory cell localization between the two mutants make these mice particularly useful models for inflammatory hair loss and autoimmune diseases in general.
External Review of Coverage Denials by Managed Care Organizations in California
Authors: Gresenz Carole Roan , Studdert David M.
Published: September 2005

External review programs have been adopted in nearly every state to give managed care enrollees the opportunity to have certain denials of health insurance coverage reviewed by physicians who are unaffiliated with their health plan. This study explores in depth a sample of cases adjudicated in California's external review program. We abstracted information from hardcopy files of several hundred cases adjudicated during 2001–2002. We describe the specific services involved in external review and the outcomes of review, analyzing the roots of disagreement in cases in which the health plan's coverage denial was overturned. We find that a subset of overturns illuminate tension in the relationship between the external review program's adjudication rules and the terms of the health insurance agreements that exist between plans and enrollees. Two critical questions face designers of external review programs: (1) What deference will be paid to specific coverage exclusions in the insurance contract between plans and enrollees? and (2) How should external review handle cases that blend medical necessity and contractual issues?
Hysteresis Loops of a Ferromagnet
Authors: Kraftmakher Yaakov
Published: September 2005

This paper describes the use of a common data acquisition system to obtain a family of hysteresis loops of a ferromagnet. Important properties of ferromagnets—nonlinear magnetization, hysteresis, and high magnetic permeability—are demonstrated.
Simulating Realistic Satellite Orbits in the Undergraduate Classroom
Authors: Knipp D. J. , Patterson E. T. , Franz A. , Head J. H. , Summers T. A. , Zirbel E. L.
Published: September 2005

Physics students are intrigued by activities in space. To link this natural curiosity with solid problem-solving skills, we developed a spreadsheet simulation for satellites moving through an atmosphere of variable density. The simulation-laboratory has been used in U.S. Air Force Academy (USAFA) introductory physics classes for several semesters. Spreadsheet variants have also been used in a USAFA advanced division space physics class, a high school advanced placement physics class, and in the Center for Integrated Space Weather Modeling graduate summer school course.
Stimulus Specificity of Gene Expression Programs Determined by Temporal Control of IKK Activity
Authors: Werner Shannon L. , Barken Derren , Hoffmann Alexander
Published: September 2005

A small number of mammalian signaling pathways mediate a myriad of distinct physiological responses to diverse cellular stimuli. Temporal control of the signaling module that contains IκB kinase (IKK), its substrate inhibitor of NF-κB (IκB), and the key inflammatory transcription factor NF-κB can allow for selective gene activation. We have demonstrated that different inflammatory stimuli induce distinct IKK profiles, and we examined the underlying molecular mechanisms. Although tumor necrosis factor-α (TNFα)-induced IKK activity was rapidly attenuated by negative feedback, lipopolysaccharide (LPS) signaling and LPS-specific gene expression programs were dependent on a cytokine-mediated positive feedback mechanism. Thus, the distinct biological responses to LPS and TNFα depend on signaling pathway-specific mechanisms that regulate the temporal profile of IKK activity.
Characterization of a
Phytophthora
Mating Hormone
Authors: Qi Jianhua , Asano Tomoyo , Jinno Masashi , Matsui Kouhei , Atsumi Keisuke , Sakagami Youji , Ojika Makoto
Published: September 2005

Water molds of the genus
Phytophthora
include many plant pathogens responsible for epidemics such as potato blight and sudden oak death, causing global economic damages. Sexual reproduction is of biological importance in
Phytophthora
and has been believed to be stimulated by unknown endogenous factors named a hormones. We describe here the chemical characterization of a
Phytophthora
mating hormone, a1, which was obtained from ~2 tons of culture fluid of one mating type of a species and which induced sexual spores on the counter-mating type at a nanogram level.
The Grand Question
Authors: Schmidt John C.
Published: September 2005

Grand Canyon
. Solving Earth's Grandest Puzzle.
By James Lawrence Powell
. Pi Press, New York, 2005. 317 pp. $27.95, C$38.95. ISBN 0-13-147989-X.

The author's account, written for the nonspecialist, centers on the efforts to understand how and when the Colorado River carved its Grand Canyon.
Molecular Octa-Uranium Rings with Alternating Nitride and Azide Bridges
Authors: Evans William J. , Kozimor Stosh A. , Ziller Joseph W.
Published: September 2005

Uranium nitrides offer potential as future nuclear fuels and as probes of metal ligand multiple bonding involving the f-block actinide metals. However, few molecular examples are available for study owing to the difficulties in synthesis. Recent advances in organoactinide chemistry have provided a route to uranium nitride complexes that expands the options for developing UN chemistry. Several 24-membered uranium nitrogen rings, (UNUN
3
)
4
, have been synthesized by reduction of sodium azide with organometallic metallocene derivatives, [(C
5
Me
4
R)
2
U][(μ-Ph)
2
BPh
2
] (R = Me, H; Me = methyl, Ph = phenyl). The nanometer-sized rings contain unusual UNU nitride linkages that have short U-N distances within the double-bond range.
Structure of SARS Coronavirus Spike Receptor-Binding Domain Complexed with Receptor
Authors: Li Fang , Li Wenhui , Farzan Michael , Harrison Stephen C.
Published: September 2005

The spike protein (S) of SARS coronavirus (SARS-CoV) attaches the virus to its cellular receptor, angiotensin-converting enzyme 2 (ACE2). A defined receptor-binding domain (RBD) on S mediates this interaction. The crystal structure at 2.9 angstrom resolution of the RBD bound with the peptidase domain of human ACE2 shows that the RBD presents a gently concave surface, which cradles the N-terminal lobe of the peptidase. The atomic details at the interface between the two proteins clarify the importance of residue changes that facilitate efficient cross-species infection and human-to-human transmission. The structure of the RBD suggests ways to make truncated disulfide-stabilized RBD variants for use in the design of coronavirus vaccines.
Global Analysis of Proteins Synthesized by
Mycobacterium smegmatis
Provides Direct Evidence for Physiological Heterogeneity in Stationary-Phase Cultures
Authors: Blokpoel Marian C. J. , Smeulders Marjan J. , Hubbard Julia A. M. , Keer Jacquie , Williams Huw D.
Published: September 2005

We have characterized the induction kinetics of ∼1,700 proteins during entry into and survival in carbon-starved stationary phase by
Mycobacterium smegmatis
. Strikingly, among the patterns of expression observed were a group of proteins that were expressed in exponential-phase cultures and severely repressed in 48-h stationary-phase cultures (Spr or stationary-phase-repressed proteins) but were synthesized again at high levels in ≥128-day stationary-phase cultures (Spr
128↑
proteins). A number of Spr
128↑
proteins were identified, and they included the heat shock protein DnaK, the tricarboxylic acid cycle enzyme succinyl coenzyme A synthase, a FixA-like flavoprotein, a single-stranded DNA binding protein, and elongation factor Tu (EF-Tu). The identification of EF-Tu as an Spr
128↑
protein is significant, as ribosomal components are known to be expressed in a growth rate-dependent way. We interpreted these data in terms of a model whereby stationary-phase mycobacteria comprise populations of cells that differ in both their growth status and gene expression patterns. To investigate this further, we constructed gene fusions between the
rpsL
gene promoter (which heads the
Mycobacterium smegmatis
operon encoding the
tuf
gene encoding EF-Tu) or the
rrnA
promoter gene and an unstable variant of green fluorescent protein. While the majority of cells in old stationary-phase cultures had low levels of fluorescence and so
rpsL
expression, a small but consistently observed population of approximately 1 in 1,000 cells was highly fluorescent. This indicates that a small fraction of the cells was expressing
rpsL
at high levels, and we argue that this represents the growing subpopulation of cells in stationary-phase cultures.
Interactions of TolB with the Translocation Domain of Colicin E9 Require an Extended TolB Box
Authors: Hands Sarah L. , Holland Lisa E. , Vankemmelbeke Mireille , Fraser Lauren , Macdonald Colin J. , Moore Geoffrey R. , James Richard , Penfold Christopher N.
Published: September 2005

The mechanism by which enzymatic E colicins such as colicin E3 (ColE3) and ColE9 cross the outer membrane, periplasm, and cytoplasmic membrane to reach the cytoplasm and thus kill
Escherichia coli
cells is unique in prokaryotic biology but is poorly understood. This requires an interaction between TolB in the periplasm and three essential residues, D35, S37, and W39, of a pentapeptide sequence called the TolB box located in the N-terminal translocation domain of the enzymatic E colicins. Here we used site-directed mutagenesis to demonstrate that the TolB box sequence in ColE9 is actually larger than the pentapeptide and extends from residues 34 to 46. The affinity of the TolB box mutants for TolB was determined by surface plasmon resonance to confirm that the loss of biological activity in all except one (N44A) of the extended TolB box mutants correlates with a reduced affinity of binding to TolB. We used a PCR mutagenesis protocol to isolate residues that restored activity to the inactive ColE9 D35A, S37A, and W39A mutants. A serine residue at position 35, a threonine residue at position 37, and phenylalanine or tyrosine residues at position 39 restored biological activity of the mutant ColE9. The average area predicted to be buried upon folding (AABUF) was correlated with the activity of the variants at positions 35, 37, and 39 of the TolB box. All active variants had AABUF profiles that were similar to the wild-type residues at those positions and provided information on the size, stereochemistry, and potential folding pattern of the residues of the TolB Box.