bluuebunny/crossref_metadata_2025 huggingface dataset:
Pharmacotherapy Review: Angiotensin Receptor Antagonists
Authors: Sica Domenic A.
Published: May 2007

Angiotensin receptor blockers are one of several drug classes that act by interfering with activity of the renin‐angiotensin axis. Drugs in this class are as effective as angiotensin‐converting enzyme inhibitors in the reduction of blood pressure in hypertensive patients. Results from a series of outcomes trials increasingly support the use of drugs in this class as cardioprotective and renoprotective agents in patients with heart failure, diabetic nephropathy, and post‐myocardial infarction.
New‐Onset Diabetes in Treated Hypertensive Patients‐Is It Clinically Significant?
Authors: Moser Marvin , Sowers James R. , Oparil Suzanne , Black Henry
Published: May 2007

Following a symposium on hypertension in Chicago on September 22, 2004, a roundtable discussion was held to discuss one of the emerging controversies in hypertension management, specifically the occurrence of new‐onset diabetes in treated nondiabetic hypertensive patients. How frequent is it? Is it just part of the metabolic syndrome that is common in hypertension, or do certain medications predispose patients to hyperglycemia? The question of the effect of other specific medications on insulin sensitivity and the possible reduction in the occurrence of diabetes in the hypertensive population with these agents was also discussed. Dr. Marvin Moser of the Yale University School of Medicine, New Haven, CT, moderated the discussion with Dr. James Sowers of the Missouri College of Medicine, Columbia, MO, Dr. Suzanne Oparil of the University of Alabama at Birmingham, Birmingham, AL, and Dr. Henry Black of the Rush College of Medicine, Chicago, IL.
The Effects of Losartan Compared to Atenolol on Stroke in Patients With Isolated Systolic Hypertension and Left Ventricular Hypertrophy. The LIFE Study
Authors: Kjeldsen Sverre E. , Lyle Paulette A. , Kizer Jorge R. , Dahlof Bjorn , Devereux Richard B. , Julius Stevo , Beevers Gareth , Faire Ulf de , Fyhrquist Frej , Ibsen Hans , Kristianson Krister , Lederballe‐Pedersen Ole , Lindholm Lars H. , Nieminen Markku S. , Omvik Per , Oparil Suzanne , Snapinn Steven M. , Harris Katherine E. , Wedel Hans
Published: May 2007

The Losartan Intervention For Endpoint reduction in hypertension (LIFE) study reported that a losartan‐based antihypertensive regimen reduced cardiovascular morbidity and mortality (composite of cardiovascular death, stroke, and myocardial infarction) more than therapy based on atenolol in patients with left ventricular hypertrophy and isolated systolic hypertension (ISH). Patients aged 55–80 years with blood pressures 160–200/<90 mm Hg were followed for a mean of 4.7 years. Blood pressure was similarly reduced in the losartan (n=660) and atenolol (n=666) ISH groups. There were 88 (6.6%) patients who experienced a stroke, 18 of which were fatal. Of patients experiencing strokes, 72.7% had an ischemic stroke. ISH patients in LIFE compared to the non‐ISH group had a higher incidence of any stroke and embolic stroke, and similar incidences of fatal, atherosclerotic, and hemorrhagiclother strokes. The incidence of any stroke (40% risk reduction [RR], p=0.02), fatal stroke (70% RR, p=0.035), and atherothrombotic stroke (45% RR, p=0.022) was significantly lower in losartan‐treated compared to the atenolol‐treated patients. The 36% RR for embolic strokes in the losartan group was not statistically significantly (p=0.33) different from the atenolol group. These data suggest that losartan‐based treatment is more effective than an atenolol‐based treatment for patients with ISH and a high risk for stroke.
Left Ventricular Mass Reduction in Type 1 Diabetic Patients With Nephropathy
Authors: Weinrauch Larry A. , Burger Andrew , Gleason Ray E. , Lee Annette T. , D'Elia John A.
Published: May 2007

Left ventricular hypertrophy regression was postulated more likely to occur in diabetic patients when renal function was preserved. Seventeen type 1 diabetic patients followed for 12 months while receiving protocol‐driven glycemic and blood pressure control had baseline and 12‐month echocardiography. Despite identical treatment resulting in similar blood pressures, patients with better renal function (below the group mean, serum creatinine ≤1.7 mg/dL) demonstrated reduction in left ventricular mass and septal thickness as well as increase in left ventricular fractional fiber shortening not observed in those with worse renal function (above the group mean, serum creatinine >1.7 mg/dL). This latter group also did not experience the improvement in glycemic control observed in those with better renal function. Regression of left ventricular mass and functional improvement can be accomplished with improved glycemic control. In the presence of renal dysfunction, however, efforts to control glycemia and cardiac work are suboptimal. Aggressive glycemic and blood pressure targets to reduce cardiovascular morbidity in this high‐risk population should be studied.
Gender‐ and Age‐Related Differences in Treatment and Control of Cardiovascular Risk Factors Among High‐Risk Patients With Angina
Authors: Hendrix Katharine H. , Mayhan Susan , Egan Brent M.
Published: May 2007

Dyslipidemic, hypertensive patients (N=48,863) were stratified by gender, age, and angina (n=2502) vs. nonangina (n=46,358) status. Comparing 95% confidence intervals yielded significant differences in treatment and cardiovascular risk factor control between subgroups. More men than women bad low‐density lipoprotein cholesterol (LDL‐C) <100 mg/dL (angina, 43.94‐43.96 vs. 34.42‐34.50; nonangina, 32.43‐32.43 vs. 17.25‐17.25) and 100‐129 mg/dL (angina, 32.12‐32.14 vs. 35.10‐35.18; nonangina, 53.86‐53.86 vs. 32.44‐32.44). More women than men had LDL‐C >130 mg/dL (angina, 27.68‐27.72 vs. 23.91‐23.93; nonangina, 38.70‐38.70 vs. 35.38‐35.39). Women were less likely than men to receive statins (angina, 69.95‐69.99 vs. 82.11‐82.13; nonangina, 59.80‐59.80 vs. 63.72‐63.72), any antilipidemic medication at all (angina, 25.93‐25.97 vs. 13.48‐13.48; nonangina, 36.73‐36.73 vs. 30.73‐30.73), or to have current cholesterol measurements (angina, 56.82‐56.88 vs. 34.54‐34.56; nonangina, 45.77‐45.77 vs. 39.75‐39.75). Primary care providers treat high‐risk patients relatively aggressively; however, opportunities to forestall cardiovascular disease may be missed in hypertensive, dyslipidemic women whose LDL‐C is often not measured and controlled.
The Role of β Blockers in the Management of Hypertension
Authors: Moser Marvin , Pickering Thomas G. , Cushman William C.
Published: May 2007

Following a hypertension symposium in New York City on February 2, 2005, a roundtable was convened to discuss the use of β blockers in the management of hypertension. Dr. Marvin Moser, Clinical Professor of Medicine at the Yale University School of Medicine, New Haven, CT, moderated the discussion. Participating in this roundtable were Dr. Thomas Pickering, Professor of Medicine at the Columbia University School of Medicine, New York, NY, and Dr. William Cushman, Professor of Preventive Medicine and Medicine at the University of Tennessee College of Medicine, Memphis, TN.
Hypertension and Cognitive Decline: Impact on Executive Function
Authors: Vicario Augusto , Martinez Carlos D. , Baretto Dolores , Casale Alejandro Diaz , Nicolosi Liliana
Published: May 2007

Hypertension is a risk factor for mild cognitive deterioration and vascular dementia. Cognitive deterioration attributable to normal aging was distinguished from cognitive deterioration related to hypertension by means of neuropsychologic tests. Sixty hypertensive patients, aged 65‐80 years, were compared with 30 normotensive individuals. Patients with a history of stroke and/or transient ischemic attacks, diabetes, atrial fibrillation, hypercholesterolemia, or bypass surgery, and those diagnosed with dementia, depression, or anxiety, were excluded. Neither gender differences, duration of hypertension (10.2±8.2 years), nor prescribed antihypertensive drug treatment had an influence on study results. Immediate recall was impaired in both groups. The hypertensive patients evinced impairment in all tests vs. the normotensive subjects. Mean deferred recall scores ± SD were 5.68±2.6 vs. 7.13±2A; p<0.01. Deficits in attention speed and executive function, as measured by nonperformance on the Trail Making Test Part B, were present in 46% of hypertensive patients vs. 13% of normotensive patients (p<0.005), with more errors made by the hypertensive patients (1.15±1.54 vs. 0.46±0.9; p<0.02). Scores on the Stroop Color and Word Test also revealed deficits in the hypertensive patients (24.7±7.6 vs. 32±10.7; p<0.005). Compared with the control group, the hypertensive participants revealed more deficits in skills involving delayed recall and prefrontal‐region skills. The relevant neuropsychologic tests were sufficiently sensitive and proved easy to use in clinical practice.
Efficacy of Combination Therapy for Systolic Blood Pressure in Patients With Severe Systolic Hypertension: The Systolic Evaluation of Lotrel Efficacy and Comparative Therapies (SELECT) Study
Authors: Neutel Joel M. , Smith David H.G. , Weber Michael A. , Schofield Lesley , Purkayastha Das , Gatlin Marjorie
Published: May 2007

Systolic hypertension is predominant among patients over 50 years of age, is a more important cardiovascular risk factor than diastolic blood pressure, and is more difficult to control than diastolic blood pressure. Consequently, the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) recommends combination therapy as first‐line treatment for patients with stage 2 hypertension. In the Systolic Evaluation of Lotrel Efficacy and Comparative Therapies (SELECT) study, 24‐hour ambulatory blood pressure monitoring was used to identify patients with systolic hypertension and to determine the impact of 8 weeks of treatment with either amlodipine besylate/benazepril HCl 5/20 mg combination therapy (n=149), amlodipine besylate 5 mg (n=146), or benazepril HCl 20 mg (n=148). Combination therapy was significantly more effective in reducing systolic blood pressure and pulse pressure than either monotherapy (p<0.0001). Significantly greater percentages of patients in the combination group compared with either monotherapy achieved blood pressure control (p<0.0001). Adverse events were low in all three treatment arms, with less peripheral edema in the combination group than in the amlodipine‐treated group. The combination of amlodipine besylate/benazepril HCl given to patients with stage 2 systolic hypertension resulted in significantly greater reductions in blood pressure and pulse pressure than those seen with monotherapy and was at least as well tolerated as the separate components. This data supports the recommendation of the JNC 7 for the use of combination therapy in patients with stage 2 hypertension.
Platelet and White Blood Cell Counts Are Elevated in Patients With the Metabolic Syndrome
Authors: Jesri Ammar , Okonofua Eni C. , Egan Brent M.
Published: May 2007

Platelet and white blood cell counts are higher among some insulin‐resistant patients and may contribute to atherothromboembolic complications. Metabolic syndrome patients are insulin resistant, often hypertensive, and at high cardiovascular disease risk, yet the relationship of platelets to the metabolic syndrome is unknown. Platelet and white blood cell counts were obtained from 135 volunteers who had measurements of blood pressure, fasting triglycerides, high‐density lipoprotein cholesterol, and glucose. A body mass index >30 kg/m2 served as a surrogate for increased waist circumference. Subjects were subdivided into three groups by the number of metabolic syndrome criteria, i.e., no metabolic syndrome risk factor (MS–0; n=40), one or two metabolic syndrome risk factors (MS1–2; n=61), and three to five metabolic syndrome risk factors (MS3–5; n=34). Platelet counts were increased significantly from 226±8 to 257±8 and 276±10 (×103/mm3) in the MS—0, MS1–2, and MS3–5 groups, respectively (p<0.01), after adjustment for age, gender, ethnicity, total cholesterol, and low‐density lipoprotein cholesterol. White blood cell counts were also increased across the three groups (5.4±0.2, 6.2±0.2, and 6.6±0.3 [×1037/mm3]; p<0.01) after multivariate adjustment. Compared with patients with zero to two metabolic syndrome risk factors, metabolic syndrome patients have higher platelet and white blood counts, which may serve as markers of a prothrombotic and proinflammatory state and contributors to atherothromboembolic risk.
Role of Angiotensin II in the Evolution of Diastolic Heart Failure
Authors: Chinnaiyan Kavitha M. , Alexander Daniel , McCullough Peter A.
Published: May 2007

More than half of all persons with heart failure (HF) have diastolic HF. The prevalence of diastolic HF increases from 46% in persons younger than 45 years to 59% in those 85 years and older. The annual mortality rate associated with diastolic HF is >10%. Diagnosis is based on signs and symptoms of HF, elevated plasma B‐type natriuretic peptide, preserved left ventricular systolic function, and evidence of diastolic dysfunction by Doppler examination on two‐dimensional echocardiography. Approximately 80% of patients with diastolic HF have increased left ventricular mass and a history of hypertension. Neurohormonal activation is a key aspect of this condition. Studies suggest that activation of the renin‐angiotensin‐aldosterone system, specifically direct cardiac effects of angiotensin II and aldosterone, contributes to the pathogenesis and progression of diastolic dysfunction. Hence, there is a rationale for use of agents that antagonize the renin‐angiotensin‐aldosterone system, such as angiotensin‐converting enzyme inhibitors, angiotensin receptor blockers, and aldosterone antagonists, in patients with heart failure.
Structural Determinants of Slow Conduction in the Canine Sinus Node
Authors: SAFFITZ JEFFREY E. , GREEN KAREN G. , SCHUESSLER RICHARD B.
Published: May 2007

Structure of Sinus Node Gap Junctions. Introduction: To elucidate the role of tissue structure as a determinant of the unique conduction properties of the sinus node. we compared the spatial distribution of intercellular connections at gap junctions in the sinus node to the more rapidly conducting crista terminalis and left ventricle, which have been studied previously.

Methods and Results: Samples of four canine sinus nodes were prepared for electron microscopy. The total number and spatial orientation of neighboring myocytes connected by ultrastructurally identified intercalated disks and gap junctions to nine randomly selected index cells were determined by sequentially examining subserial sections. Sinus node cells were sparsely interconnected compared to the extent of interconnections observed previously in other tissues. A typical sinus node cell was connected to only 4.8 ± 0.7 neighbors compared with 11.3 ± 2.2 cells in the left ventricle and 6.4 ± 1.7 cells in the crista terminalis. Sinus node interconnections occurred at small intercalated disks that usually connected cells in partial side‐to‐side and end‐to‐end juxtaposition. In contrast, left ventricular myocytes are interconnected at large intercalated disks that adjoin many cells in pure side‐to‐side and end‐to‐end orientations. Crista terminalis myocytes are connected primarily in end‐to‐end fashion. The aggregate gap junction profile length per unit myocyte area was 26.5 times greater in the left ventricle and 5.0 times greater in the crista terminalis than in the sinus node.

Conclusion: Sinus node myocytes exhibit small, sparsely distributed gap junctions that interconnect cells in complex patterns of lateral and terminal apposition. These structural features are consistent with the unique conduction properties of the sinus node.
Pharmacologic Management of Atrial Fibrillation
Authors: RILEY REED D. , PRITCHETT EDWARD L.C.
Published: May 2007

Pharmacologic Management of AF. In an era when many electrophystologic problems are routinely treated with invasive procedures or implantable devices, drugs remain the cornerstones of treatment for atrial fibrillation. Atrial fibrillation may present as an episodic rhythm in patients who are primarily in sinus rhythm or it may be manifested as rhythm disorder that is permanent. Patients who appear to have an episodic rhythm disorder may be found to be in atrial fibrillation permanently when followed for long periods of time, and prognosis in the two forms is similar. It is, therefore, useful to consider them different manifestations in the same spectrum of disease. This review will address pharmacologic approaches designed to: (1) slow ventricular response; (2) restore sinus rhythm; (3) reduce occurrences of atrial fibrillation; and (4) prevent thromboembolic complications. Nonpharmacologic approaches to treating atrial fibrillation will be briefly reviewed.
Book Review
Authors: Fisch Charles
Published: May 2007

Practical Management of Cardiac Arrhythmias. Edited by Nabil El‐Sherif and Jean Lekieffre
Agonal Sequences in a Filmed Suicidal Hanging: Analysis of Respiratory and Movement Responses to Asphyxia by Hanging*
Authors: Sauvageau Anny , Racette Stéphanie
Published: May 2007

The forensic literature on the pathophysiology of human hanging is still limited. Therefore, forensic pathologists often feel uncomfortable when confronted with related questions. Here presented is the filmed suicidal hanging of a 37‐year‐old man. This recording allows a unique analysis of agonal movement sequences: loss of consciousness (13 sec), convulsions (15 sec), decortication rigidity (21 sec), decerebration rigidity (46 sec), second decortication rigidity (1 min 11 sec), loss of muscle tone, (1 min 38 sec) and last isolated muscle movement (4 min 10 sec). As for respiratory responses, very deep respiratory attempts started at 20 sec. Respiratory movements progressively decreased and completely stopped at 2 min. Despite the fact that extending the presented data on all cases of hanging asphyxia would be a mistake, this case gives a very interesting insight into movement and respiratory response to asphyxia by hanging.
The Impact of Virtual Operation Planning on Liver Surgery
Authors: Fischer L. , Hoffmann K. , Neumann J.‐O. , Schöbinger M. , Grenacher L. , Radeleff B. , Friess H. , Meinzer H. P. , Büchler M. W. , Schmidt J. , Schemmer P.
Published: May 2007

The increasing complexity of hepato‐biliary surgery, including major hepatic resections and living donor liver transplantation (LDLT), has lead to an increasing demand for sophisticated imaging modalities. Standard operation planning for hepatic resections and preoperative donor and recipient work‐up for LDLT is based on two‐dimensional computed tomography (CT) images and magnetic resonance imaging. However, even modern multidetector CT scanners are not able to perform routinely three‐dimensional (3D) visualization needed for operation planning in liver surgery or LDLT. As a consequence, special‐purpose computer‐based operation planning systems have been developed that leverage the possibilities of modern image processing to improve surgical planning. The advances in technology enable surgeons to analyse and to visualize the anatomy of the human liver including the vascular structures within the human liver and define the exact volumetric data of the liver tissue to be resected or preserved. Furthermore, 3D visualization of the vessel architecture within the human liver allows a reliable estimation of the amount of liver tissue that could be at risk after resection because of inadequate hepatovenous drainage. Because of its clinical usefulness and real‐time visualization capabilities we already use an operation planning system in selected patients prior to liver resection and before donor hepatectomy for LDLT as a standard.
Turned, Machined Versus Double‐Etched Dental Implants In Vivo
Authors: Al‐Nawas B. , Hangen U. , Duschner H. , Krummenauer F. , Wagner W.
Published: May 2007

Background:  Positive effects on the clinical outcome of moderately rough implant surfaces are described. Intercomparison of clinical data, however, is rarely found.

Purpose:  The aim of this study was to compare the clinical results of two macroscopically identical implants, the one with a turned, machined and the other with an etched surface.

Materials and Methods:  In a retrospective cohort study, the included implants followed the criteria: standard surgical protocol, >12 months in situ; minimally rough self‐threading implants with a turned, machined surface (Mk IITM Nobel Biocare AB, Göteborg, Sweden], n=210); etched implants of the same macrodesign (3iTM Implant Innovations Inc., Palm Beach Gardens, FL, USA], n=151), length ≥ 10 mm. Clinical data and implant success were rated. Resonance frequency analysis (RFA) and Periotest® (Siemens AG, Bensheim, Germany) were measured and related to the corresponding implant survival rate in the respective group.

Results:  The total number of implants was 361, of which 264 (73%) were subject to clinical reexamination. RFA and Periotest could be recorded in 25% of the implants. Neither clinically relevant nor statistically significant differences between the surface designs were found in the RFA (64 ± 8.6 vs 63 ± 9.7), in Periotest (−2 ± 3.3 vs −1 ± 5.1), and in mean survival periods (49 months, 95% confidence interval CI]: 46–51 months, for the turned vs 46 months, 95% CI: 43–49 months, for the double‐etched implant). After osteoplastic procedures, a significantly higher rate of implant losses in the turned, machined implant group was observed (17 vs 1) with a mean survival period of 43 (40–46) months for the turned and 46 (45–48) months for the double‐etched implants.

Conclusion:  No difference between implants with two different minimally rough surfaces was found. A positive effect of surface roughness is observed in poor quality bone, but the pivotal proof of this effect is still lacking.
COLOR AND OXIDATIVE PROPERTIES OF IRRADIATED WHOLE MUSCLE BEEF1
Authors: LUCHSINGER S. E. , KROPF D. H. , GARCÍA ZEPEDA C. M. , HUNT M. C. , STRODA S. L. , MARSDEN J. L. , KASTNER C. L.
Published: May 2007

The effects of two doses (2.0 and 3.5 kG'y) of nonradioactive irradiation on color and oxidative properties were determined and compared to nonirradiated controls for frozen and chilled vacuum‐packaged boneless beef steaks. The chilled steaks were repackaged in oxygen‐permeable film 14 days after irradiation. Irradiation up to 3.5 kGy had minimal effects on color and oxidative rancidity and significantly reduced bacterial counts of frozen and chilled, vacuum‐packaged, beef steaks stored and/or displayed for up to 28 days. Irradiated steaks that were rewrapped in permeable film were microbially acceptable at 5 days of display and had more color stabiliry than the controls. Although no differences in TBA numbers between dose levels were observed for chilled steaks rewrapped in permeable film, these steaks had a TBA number of 2.1 after 5 days of retail display compared to 0.2 for vacuum‐packaged steaks displayed for 14 days.
THE EFFECT OF OXYGEN SCAVENGERS ON THE COLOR STABILITY AND SHELF‐LIFE OF CO, MASTER PACKAGED PORK
Authors: DOHERTY A. M. , ALLEN P.
Published: May 2007

Pork chops were stored with and without O2 scavengers in a modified atmosphere (50% CO2/50% N, or 100% CO2) master pack system at 0C for up to 21 days, At 7‐day intervals, the chops were displayed at ca. 4.5C for 96 h. Color (L, a, b, hue and chroma); panelist assessments of color and odor; and drip losses were recorded. Oxygen scavengers reduced O2 levels, resulting in chops that were generally as red as flesh, but tended to have higher hue angles at 0 h, and towards the end of display (P<0.05). Visually, chops packaged in 50% CO2/50% N2 were less acceptable than flesh (P<0.05). There were no odor differences between flesh and packaged chops. Fresh chops had lower drip losses than packaged (P<0.05). An acceptable display life was obtained for pork chops stored for up to 21 days in a modified atmosphere CO2 master pack containing O2 scavengers.
APPLICATION OF α‐TOCOPHEROL IN DRY CHINESE POWCHICKEN SAUSAGES
Authors: YIN M.‐C. , TU H.‐Y. , CHENG W.‐S.
Published: May 2007

Chicken breast at 8%, 17% and 25% levels was used to replace pork fat in a low‐fat dry Chinese sausage. This replacement resulted in more lipid and oxymyoglobin oxidation; also pH values declined (P<0.05) during 4C storage. Cooking loss decreased with increasing chicken cantent in sausaga (P<0.05). The addition of α‐tocopherol to pork/chicken sausages delayed lipid and oxymyoglobin oxidation (P<0.05) but did not influence pH value or cooking loss.
ULTRASTRUCTURAL CHANGES IN BOVINE LONGISSIMUS MUSCLE CAUSED BY THE HYDRODYNE PROCESS
Authors: ZUCKEFWAN H. , SOLOMON M.B.
Published: May 2007

Transmission electron microscopy was used to examine the influence of the Hydrodyne process, a new technology for tenderizing meat in the raw state, on the ultrastructural characteristics of bovine longissimus muscle. Myofibrillar fiagmentation in the region adjacent to the Z‐lines was clearly evident. Fragments of Z‐lines were attached to the A‐band on both sides of the fractures. These fractures resulted in increased intrumyofibrillar spaces with longitudinal gaps or splits in the myofibril lattice (lattice of filaments formed inside the myofibril). These observations offer evidence as to why there is a significant improvement in meat tenderness when meat is treated with the Hydrodyne process.
RELATIONSHIPS AMONG CHEMICAL, COOKING AND COLOR PROPERTIES OF BEEF PATTIES COOKED TO FOUR INTERNAL TEMPERATURES
Authors: BERRY B.W. , LYON B.G. , SODERBERG D. , CLINCH N.
Published: May 2007

A study involving five laboratories and nationwide sampling of ground beef was undertaken to determine cooking and color properties of patties cooked to 52.7, 65.6, 71.1 and 79.4C. The design of the study included purchase location (local, distant) and patty handling prior to cooking Pesh, thawed either as patties or bulk ground beef). Purchase location was not a statistically significant influence on cooking and color properties. Patties processed from bulk thawed product had a higher amount of brown cooked color. A strong relationship existed between visual and instrumental measures of red color in cooked patties. However, correlations among other cooking properties were low. Patties with higher fat content were associated with shorter cooking times, lower cooking yields and more brown cooked color. The low relationships between raw and cooked patty properties limits the use of raw ground beef properties as predictors of food safety in cooked beef patties. This further supports the use of instant read meat thermometers in cooking beef patties to at least 71C.
Design of Mutation‐resistant HIV Protease Inhibitors with the Substrate Envelope Hypothesis
Authors: Chellappan Sripriya , Kiran Kumar Reddy G. S. , Ali Akbar , Nalam Madhavi N. L. , Anjum Saima Ghafoor , Cao Hong , Kairys Visvaldas , Fernandes Miguel X. , Altman Michael D. , Tidor Bruce , Rana Tariq M. , Schiffer Celia A. , Gilson Michael K.
Published: May 2007

There is a clinical need for HIV protease inhibitors that can evade resistance mutations. One possible approach to designing such inhibitors relies upon the crystallographic observation that the substrates of HIV protease occupy a rather constant region within the binding site. In particular, it has been hypothesized that inhibitors which lie within this region will tend to resist clinically relevant mutations. The present study offers the first prospective evaluation of this hypothesis, via computational design of inhibitors predicted to conform to the substrate envelope, followed by synthesis and evaluation against wild‐type and mutant proteases, as well as structural studies of complexes of the designed inhibitors with HIV protease. The results support the utility of the substrate envelope hypothesis as a guide to the design of robust protease inhibitors.
The economic significance of “insignificant” rules
Authors: Hahn Robert , Cecot Caroline
Published: May 2007

We know relatively little about the economic effects of “insignificant” rules because they are not typically analyzed. Yet, these rules could be cumulatively important. We provide an economic analysis of one proposed rule to control hazardous air pollutants, which is not considered to be economically significant. This rule is of particular interest because it is one of the first in a long series of rules that Environmental Protection Agency (EPA) will consider for limiting hazardous air pollutant emissions. Our analysis suggests that the proposed controls that EPA has considered are not likely to pass a benefit–cost test. We recommend that an agency base its decision to allocate additional resources to benefit–cost analysis on the expected value of the improved information. In addition, agencies should consider applying a rule of thumb that would specify a threshold level of risk reduction that needs to be achieved before some kinds of regulation are considered.
Interstitial Heat Transfer Coefficient and Dispersion Conductivity in
Compressed Metal Foam Heat Sinks
Authors: Tzeng Sheng-Chung , Jeng Tzer-Ming
Published: May 2007

This work experimentally and numerically investigates the heat transfer in uncompressed∕compressed metal foams. Experiments were conducted to obtain the thermal characteristics of a rectangular channel filled with aluminum foams using air as the fluid medium. The experimental data reveal that the uncompressed sample has a larger Nusselt number (Nu) than the compressed sample. The 0.93 porosity sample has the largest average Nu followed by the 0.7 porosity sample; the 0.8 porosity sample has the worst average Nu. The experimental data concerning the 0.93 porosity samples (uncompressed samples) were consistent with the numerical predictions obtained using the model for high-porosity metal foam, reported elsewhere. Finally, a numerical model to simulate flow and heat transfer characteristics in compressed metal foams is presented and the interstitial heat transfer coefficient and dispersion conductivity were semi-empirically determined.
Flow Structure and Enhanced Heat Transfer in Channel Flow With
Dimpled Surfaces: Application to Heat Sinks in Microelectronic
Cooling
Authors: Silva Carlos , Marotta Egidio , Fletcher Leroy
Published: May 2007

The use of dimple technology for improvement in friction factors and enhancement of heat transfer has been attracting the attention of many scientists and engineers. Numerical and experimental studies have shown there is a positive improvement (two-fold on average) in Nusselt number when dimpled surfaces are compared to flat plates, and this improvement is achieved with pressure drop penalties that are small when compared to other more intrusive types of turbulence promoters. When arrays of specific dimple geometry are used, pressure drop penalties are roughly equivalent to the heat transfer improvement. This, at least theoretically, will enable the design of smaller heat transfer devices such as heat sinks, which are especially appealing in those applications where size is an important design factor. A literature review of numerical modeling and experiments on flow over dimpled surfaces was performed, and key parameters and flow structure were identified and summarized. With these premises, a numerical model was developed. The model was validated with published experimental data from selected papers and fine tuned for channel flow within the laminar flow regime. Subsequently, the model was employed for a specific application to heat sinks for microelectronic cooling. This paper, then, provides a comparative evaluation of dimple technology for improving heat transfer in microelectronic systems.
Inelastic Deformation and Fatigue of Solder Alloys Under Complicated
Load Conditions
Authors: Liang J. , Dariavach N. , Callahan P. , Shangguan D.
Published: May 2007

Fundamental study of deformation and fatigue fracture behavior of solder alloys under complex load conditions is a key to enabling implementation of sophisticated three-dimensional (3D) time-dependent nonlinear finite-element stress and strain analyses for the life assessment for electronic packages and assemblies. In this study, the rate-dependent deformation and fatigue fracture behavior of Sn3.8Ag0.7CuPb-free alloy and Sn–Pb eutectic alloy was investigated with thin-walled specimens using a biaxial servo-controlled tension–torsion material testing system, with solder alloys subjected to a variety of complex load conditions: pure shearing at strain rates between 6.7×10−7∕s and 1.3×10−1∕s, creep at temperatures ranging from room temperature up to 125°C, and cyclic loading with frequencies of 0.001Hz to 3Hz. Biaxial stress conditions were imposed to investigate the effects of multiaxial stresses on deformation behavior. The effects of frequency and temperature on cyclic deformation and fatigue facture were investigated for lead-free Sn3.8Ag0.7Cu and Sn–Pb eutectic solder. Fractography of fatigue tested samples was also conducted to determine possible fatigue failure mechanisms.
General Uncertainty Analysis for Manual Wheelchair Propulsion Dynamics and Development of an Instrumented Wheel
Authors: Mallakzadeh M. , Sassani F.
Published: May 2007

Manual wheelchair propulsion (MWP) is an inefficient and physically straining process. A reliably fabricated and instrumented wheel can help researchers to accurately calculate the forces and moments exerted by the wheelchair users and propose strategies to improve MWP. In this study, an instrumented wheel is designed, fabricated, and validated by using general uncertainty analysis. A six-component transducer is used to measure three-dimensional forces and moments applied by the wheelchair user on the handrim. The output of the transducer are forces and moments, which are directly transmitted to a PC using a USB port. By developing the transformation equations, the actual forces and moments on the hand of the wheelchair user are calculated. The angular position of the hand on the handrim is calculated from the kinetic data obtained through the instrumented wheel, and the derived equations. The general uncertainty analysis method is used to calculate the uncertainty values for the variables of interest with the Taylor series expansions. An analysis of the results shows that it is possible to obtain reliable information for MWP by using the instrumented wheel. Most of the data have uncertainties under 5% during much of the propulsion phase, and the patterns and overall behavior of the results are comparable to published data.
Application of the Finite Element Technique in the Design and Evaluation of the Artificial Facets for the Lumbar Spine
Authors: Shaw Miranda N. , Goel Vijay K. , Sairyo Koichi , Jangra Jayant , Biyani Ashok , Ebraheim Nabil
Published: May 2007

An experimentally validated three-dimensional (3D) finite element (FE) model of the ligamentous L3–S1 segment was used to study the effects of artificial facet designs on the segment biomechanics (motion, facet loads, and stresses). The intact model was modified to simulate several artificial facet designs across the L4–L5 segment including capping with and without screws and pedicle screw based designs with sliding articulating surfaces. For the pedicle screw based design, the effect of increasing the connecting shaft thickness and increasing width surrounding the pedicle screw, butted against the vertebral pedicle for further support, was studied. All of the FE models were evaluated in response to 6 Nm moment in extension, flexion, bending, and rotation. The predicted increases in motion, compared to the intact case, were smaller. The predicted facet loads decreased up to 25.7% in extension and 25.1% in bending at the implanted level as compared to intact spine segment. For all of the loading modes, the stresses in both implant designs were less than the yield stress of titanium. Therefore, the implants are unlikely to fail. Additional cadaver and other experimental protocols are essential for the evaluations of the most appropriate designs identified through the FE investigations.
A Lagrange Multiplier Mixed Finite Element Formulation for Three-Dimensional Contact of Biphasic Tissues
Authors: Yang Taiseung , Spilker Robert L.
Published: May 2007

A three-dimensional (3D) contact finite element formulation has been developed for biological soft tissue-to-tissue contact analysis. The linear biphasic theory of Mow, Holmes, and Lai (1984, J. Biomech., 17(5), pp. 377–394) based on continuum mixture theory, is adopted to describe the hydrated soft tissue as a continuum of solid and fluid phases. Four contact continuity conditions derived for biphasic mixtures by Hou et al. (1989, ASME J. Biomech. Eng., 111(1), pp. 78–87) are introduced on the assumed contact surface, and a weighted residual method has been used to derive a mixed velocity-pressure finite element contact formulation. The Lagrange multiplier method is used to enforce two of the four contact continuity conditions, while the other two conditions are introduced directly into the weighted residual statement. Alternate formulations are possible, which differ in the choice of continuity conditions that are enforced with Lagrange multipliers. Primary attention is focused on a formulation that enforces the normal solid traction and relative fluid flow continuity conditions on the contact surface using Lagrange multipliers. An alternate approach, in which the multipliers enforce normal solid traction and pressure continuity conditions, is also discussed. The contact nonlinearity is treated with an iterative algorithm, where the assumed area is either extended or reduced based on the validity of the solution relative to contact conditions. The resulting first-order system of equations is solved in time using the generalized finite difference scheme. The formulation is validated by a series of increasingly complex canonical problems, including the confined and unconfined compression, the Hertz contact problem, and two biphasic indentation tests. As a clinical demonstration of the capability of the contact analysis, the gleno-humeral joint contact of human shoulders is analyzed using an idealized 3D geometry. In the joint, both glenoid and humeral head cartilage experience maximum tensile and compressive stresses are at the cartilage-bone interface, away from the center of the contact area.
Metal Chloride Reductions with Aromatic Radical Anions. The Magnesium Chloride Catalysed Cleavage of Tetrahydrofuran by Sodium Naphthalene Radical Anion
Authors: Steele Barry R. , Heropoulos Georgios A. , Screttas Constantinos G.
Published: May 2007

Activated metals for organic synthesis are often prepared by reduction of metal salts using alkali metal aromatic radical anions. The reduction of magnesium chloride has been examined by NMR. Whereas the expected reduction to the metal occurred with lithium or potassium naphthalene radical anion, under certain conditions, with sodium naphthalene radical anion, no metallic magnesium was precipitated and dark red solutions were obtained. It was also found that solutions of sodium naphthalene radical anion in tetrahydrofuran, in the presence of a catalytic amount of magnesium chloride, quickly became diamagnetic. A mechanism involving bimetallic species is postulated to explain the results.
Reactions of Bis(phenyldiazenido)rhenium Complex [ReBr2(NNPh)2(PPh3)2]Br with Carbon Monoxide and Alk-1-ynes
Authors: Costa Maria Teresa A. R. S. da , Guedes da Silva Maria Fátima C. , Fraústo Da Silva João J. R. , Pombeiro Armando J. L.
Published: May 2007

The conversion of the bis(diazenido) complex [ReBr2(NNPh)2(PPh3)2]Br (1) to the mono(diazenido) complex [ReBr3(NNPh)(PPh3)2] (2) is promoted by alk-1-ynes, whereas the reaction with CO leads to the mixed dicarbonylmono(diazenido) Re(III) species [ReBr(CO)2- (NNPh)(PPh3)2]Br (3). Both reactions are suggested to occur via related pathways involving a nucleophilic displacement of one of the diazenide ligands by Br-. Reduction of the phenyldiazenide ligand in 2 occurs in the attempted reaction with HC≡CPh to give the nitrido complex [ReBr2(N)(PPh3)2] (4) and the bis(diazenido) species [ReBr2(NNPh)2(PPh3)2] (5) and [ReBr(NNPh)2(PPh3)2] (6).
Occupational risk factors in Alzheimers disease: a review assessing the quality of published epidemiological studies
Authors: Santibez Miguel , Bolumar Francisco , Garca Ana M
Published: May 2007

Epidemiological evidence of an association between Alzheimers disease AD and the most frequently studied occupational exposurespesticides, solvents, electromagnetic fields EMF, lead and aluminiumis inconsistent. Epidemiological studies published up to June of 2003 were systematically searched through PubMed and Toxline. Twenty-four studies 21 casecontrol and 3 cohort studies were included. Median GQI was 36.6 range 19.562.9. Most of the casecontrol studies had a GQI of <50. The study with the highest score was a cohort study. Likelihood of exposure misclassification bias affected 18 of the 24 studies. Opportunity for bias arising from the use of surrogate informants affected 17 studies, followed by disease misclassification 11 studies and selection bias 10 studies. Eleven studies explored the relationship of AD with solvents, seven with EMF, six with pesticides, six with lead and three with aluminium. For pesticides, studies of greater quality and prospective design found increased and statistically significant associations. For the remaining occupational agents, the evidence of association is less consistent for solvents and EMF or absent for lead and aluminium.
Skin, gland, and urine odors elicit intense investigation by male gray short-tailed opossums, Monodelphis domestica
Authors: Zuri Ido , Nguyen Danielle , Daniels Yasmine , Halpern Mimi
Published: May 2007

Chemical signaling between animals of the same species is common among vertebrates. We have reported this phenomenon in the gray short-tailed opossum, Monodelphis domestica (Wagner, 1842). We now find that male opossums investigate odors derived from the mandibular and flank regions and from urine of male and female opossums and from the sternal gland of male opossums significantly more than distilled water. Males investigate female odors significantly more than male odors. They also investigate strange male odors significantly more than their own odors when similar body parts were compared. The males investigate female flank odors significantly longer than female urine odors when these were paired, but the time spent investigating other pairings of female odors was not significantly different. Furthermore, experimental males, unlike females tested in former studies, discriminate between urine of male and of female conspecifics when compared with water control. We hypothesize that male opossums require information about the presence of male conspecifics that recently traversed their home range to avoid potential conflicts. Urine from diestrous females signals the proximity of a female that has not already mated.
An attempt to differentiate sympatricIchthyomyzonammocoetes using meristic, morphological, pigmentation, and gonad analyses
Authors: Neave F.B. , Mandrak N.E. , Docker M.F. , Noakes D.L.
Published: May 2007

We assessed characters that could be used to differentiate ammocoetes of chestnut lamprey ( Ichthyomyzon castaneus Girard, 1858), northern brook lamprey ( Ichthyomyzon fossor Reighard and Cummins, 1916), and silver lamprey ( Ichthyomyzon unicuspis Hubbs and Trautman, 1937). We sampled ammocoetes of the three species from 25 streams around the Great Lakes. Existing genetic markers were used to identify chestnut lamprey for this study, but the lack of genetic markers for silver and northern brook lampreys forced our preliminary classification of these two species to be based on stream-specific catch records of adults. Comparison of ammocoete gonads was inconclusive as a technique to distinguish between these two species. Other characters examined (including pigmentation patterns, morphometric characters, body shape, and myomere counts) varied significantly among species, but were inadequate for use as diagnostic characters because of high intraspecific variation and overlapping ranges. Chestnut lamprey ammocoetes were sometimes distinguishable by their pigmented lateral line organs, but this character was not always apparent. The lack of distinguishing characteristics makes existing taxonomic keys misleading for identifying Ichthyomyzon lamprey larvae.
STRUCTURAL AND OPTICAL PROPERTIES OF SOL-GEL DERIVED BARIUM TITANATE THIN FILM
Authors: BASANTAKUMAR SHARMA H.
Published: May 2007

Ferroelectric barium titanate ( BaTiO 3) films have been prepared from barium acetate and titanium (IV) isopropoxide precursors by the sol-gel technique. The structural and optical properties of films annealed at different temperatures have been investigated. The as-fired films were found to be amorphous and crystallized to the tetragonal phase after annealing at 700°C for one hour in air. The lattice constants "a" and "c" were found to be 3.996 Å and 4.040 Å respectively. The X-ray density of the crystalline film was about 6.00 g · cm -3. The amorphous film showed very high transparency (~95%), which decreased slightly after crystallization (~90%). The band gap and the refractive index of the amorphous and crystalline films were estimated. The influences of porosity on the optical properties of films have also been investigated. The optical dispersion data are also analyzed in the light of the single oscillator model, and are discussed.
ADSORPTION, DIFFUSION AND GROWTH MODE OF ZnO THIN FILM FROM FIRST PRINCIPLES
Authors: CHUN YANG , LI Y. R. , YI YU
Published: May 2007

A heteroepitaxial growth model of the ZnO film on sapphire (0001) is calculated by using a plane wave ultrasoft pseudo-potential method based on density functional theory. It is found that interfacial atoms have different diffusivity at 400°C, 600°C and 800°C. The temperature has a decisive effect on the surface and interface structures of ZnO /α- Al 2 O 3 (0001) and on the growth mode of ZnO thin films. In the whole process of the adsorption and growth of ZnO , the diffusivity of O atoms is higher than that of Zn , and the interlayer diffusion has an important impact on the homogeneous growth of thin films. There are two growth modes of ZnO on sapphire (0001), which is further demonstrated by theoretical calculation. The growth mode at about 400°C has a character of mainly spiral-twisted growth with Zn -hexagonal symmetry structure, and it is favorable for forming the Zn -terminated surface. But in the case of 600°C, a regular in-plane growth is observed, which facilitates the O -terminated surface of the ZnO thin film. It can be observed from the calculation that the vacancies of Zn where the atomic layer is near to the α- Al 2 O 3 (0001) surface is more than that of O atoms.
DEPENDENCE OF TEMPERATURE ON THE STRUCTURE AND PHOTOLUMINESCENCE OF ZnO THIN FILMS FABRICATED BY PULSED Nd:YAG LASER DEPOSITION ON SAPPHIRE SUBSTRATES
Authors: WEI XIAN QI , MAN BAO-YUAN
Published: May 2007

Zinc oxide ( ZnO ) thin films were grown on sapphire substrates at different deposition temperatures by pulsed laser deposition (PLD). The structure, composition and optical properties of deposited thin films have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), Raman and photoluminescence (PL) spectra. The results show that the ZnO thin films deposited at 500°C have the best crystalline quality with hexagonal structure, surface morphology and stoichiometric composition. The PL spectrum reveals that the sample possesses the strongest ultraviolet (UV) emission at 370 nm and the weakest blue emission at 459 nm under this condition. Raman spectra and weak blue emission of PL spectra show that very few oxygen vacancies exist in the ZnO thin films.