bluuebunny/crossref_metadata_2025 huggingface dataset:
Distribution of Halothane and the Metabolites Trifluoroacetic Acid and Bromide in the Conceptus after Halothane Inhalation by Pregnant Mice
Authors: Ghantous Hanan , Parnerud I. , Danielsson B. R. G. , Dencker L.
Published: July 2010

Abstract:Mice in late stage of gestation were exposed to halothane at various concentrations for 1 hr, and were killed at different time intervals after discontinuance of inhalation. The concentration of halothane in maternal plasma decreased rapidly, and in the amniotic fluid the halothane never reached more than 20% of maternal plasma levels. Trifluoroacetic acid (TFA) and bromide, formed mainly by maternal metabolism of halothane, accumulated in foetus and amniotic fluid with time, and reached plateau levels in amniotic fluid between 4 and 24 hrs. TFA infused intravenously to the mother reached higher levels in amniotic fluid after long survival times, than in maternal plasma. Equilibrium dialysis experiments showed that TFA and trichloroacetic acid (TCA) (previously shown to accumulate in amniotic fluid) were bound to amniotic fluid macromolecules only to approximately 20–30 percent. This was at the same magnitude (or lower) as compared to binding in maternal plasma, suggesting that such binding did not contribute to the observed retention in the amniotic fluid. Other possible explanations for the slow accumulation and long‐term retention in amniotic fluid are transport by bulk flow via foetus, excretion via foetal urine, or paraplacentally through endometrium and foetal membranes, followed by trapping in the amniotic fluid. The significance of this accumulation of metabolites of halogenated organic solvents and halothane for their foetotoxicity is not clear.
Lack of Effect of Non‐Steroid Antiinflammatory Drugs on Lithium Clearance and on Delivery of Tubular Fluid to the Loop of Henle in Rats
Authors: Lassen Erik , Thomsen Klaus , Sørensen Søren S. , Pedersen Erling B.
Published: July 2010

Abstract: This paper examines a possible interaction between non‐steroid antiinflammatory drugs (NSAI drugs) and renal lithium clearance in conscious, unoperated rats with diabetes insipidus (Brattleboro strain) and ordinary Wistar rats. The drugs were given with the food for 5 days before clearance determinations in the following daily doses per kg body weight: acetylsalicylic acid 115 mg/kg, phenylbutazone 20 mg/kg, indomethacin 5 mg/kg, and penicillamine 65 mg/kg. None of the drugs affected the lithium clearance. Also urine flow, sodium clearance, potassium clearance, and prostaglandin E2 excretion remained unaffected by the treatments. The results suggest that a continued lowering of lithium clearance cannot be produced, at least not by administration of the drugs with the food. Since lithium clearance is a quantitative measure of the delivery of tubular fluid from the proximal tubules to the loop of Henle, the results also suggest that chronic administration of NSAI drugs does not influence delivery from the proximal tubules in rats. The lowering of lithium clearance observed by others after administration of the drugs by injection or by gastric tube may have been transient, lasting only for a short period after each administration.
Effect of Some Metal Compounds on the Ca2+ Binding and Ca2+‐Mg2+‐ATPase Activity of Eggshell Gland Mucosa Homogenate from the Domestic Fowl
Authors: Lundholm C. E. , Mathson K.
Published: July 2010

Abstract: Some metal ions, e.g. Hg2+, Cd2+ and Al3+, can have the effects as ecotoxicological agents, of causing eggshell thinning and breakage in birds. In a homogenate of the Ca2+‐secreting part of the eggshell gland mucosa, a study was made of the influence of Hg2+, Cd2+, Cu2+, Pb2+, methyl‐Hg+, Zn2+, V3+, Al3+ and Ni2+ in different concentrations on the rate of ATP‐dependent 10−4 M Ca2+ binding. All compounds had an inhibitory action. The most potent metal (Hg2+) produced 50% inhibition (IC50) at 1.1 × 10−6 M, whereas this value for the least potent compound (Ni2+) was 9 × 10−4 M. The specific Ca2+‐Mg2+‐ATPase activity was also inhibited by the tested metal ions. In all cases except methyl‐Hg+ the IC50 for this activity was lower than that for Ca2+ binding. The most potent ion in this respect was Cd2+, with an IC50 of 8 × 10−8 M, and the least potent was methyl‐Hg+, with an IC50 of 1.4 × 10−3 M. Pb2+ and Cd2+ in a concentration range of 10−5‐10−4 stimulated the Mg2+‐ATPase activity, however, to almost the same extent as 10−4 M Ca2+. A possible explanation for this effect is that these ions may have an affinity for sites of Ca2+ binding of the polypeptide calmodulin and thereby influence the Ca2+ metabolism of the shell gland mucosa.
Nifedipine – A Survey of Adverse Effects – Four years' reporting in Sweden
Authors: Myrhed Mårten , Wiholm Bengt‐Erik
Published: July 2010

Abstract: During the period February 1983 to December 1984 the Swedish Adverse Drug Reactions Advisory Committee received 80 reports describing 116 adverse reactions with a possible or probable connection to nifedipine. The most frequently reported reactions are oedema, tachycardia, headache and rash. Confusion and sleep disorders constitute 8 cases. Impaired angina is a potentially serious reaction and one patient developed myocardial infarction.
Cerebral Vasospasm and Calcium Channel Blockade. Nimodipine treatment in patients with aneurysmal subarachnoid hemorrhage
Authors: Brandt Lennart , Ljunggren Bengt , Säveland Hans , Andersson Karl‐Erik , Vinge Ellen
Published: July 2010

Abstract: In patients with aneurysmal subarachnoid hemorrhage (SAH), delayed ischemic cerebral dysfunction (DID or symptomatic vasospasm) with subsequent fixed neurological dysfunction (FND) is a frequent and most feared complication induced by the hemorrhage. Aneurysm operation during the acute stage with intraoperative evacuation of bloodcontaminated cerebrospinal fluid (CSF) from the basal cisterns and subarachnoid spaces has reduced this complication. Nevertheless despite early operation, DID with FND occurs in 13 – 20% or more. In a series of 100 individuals with a ruptured supratentorial aneurysm, who were subjected to aneurysm operation in the acute stage and who subsequently received intravenous treatment with the calcium channel blocker nimodipine, the occurrence of DID with FND was reduced to 5%.
Migraine Treatment with Calcium Channel Blockers
Authors: Andersson Karl‐Erik , Brandt Lennart , Hindfelt Bengt , Ryman Torsten
Published: July 2010

Abstract: Irrespective of their mechanism of action, which so far has not been clarified, calcium channel blockers (CCBs) have a documented prophylactic effect on classical and common migraine, as well as on cluster headache. The drugs may reduce migraine prodromes, the frequency of migraine attacks, and also decrease the severity and possibly the duration of these attacks. Notably, their optimum effect is often seen after more than 2 months of treatment. Side effects seem to be few and mild. Whether or not there are differences in therapeutic efficacy between different CCBs is presently unclear. As comparisons with other alternatives of treatment are sparse, the place of CCBs in migraine therapy remains to be established.
Hypertrophic Cardiomyopathy
Authors: Landmark Knud
Published: July 2010

Abstract: Hypertrophic cardiomyopathy is characterized by a hypertrophic and non‐dilated left ventricle with disproportionate involvement of the intraventricular septum compared to the free walls, and by varying degrees of outflow obstruction during systole. Its symptoms and clinical course, pathogenesis and treatment are briefly discussed. It is speculated whether hypertrophic cardiomyopathy and hypertension are both caused by systemic disorders of calcium channels and calcium uptake and binding by cardiac and smooth muscle membranes, respectively.
Effects of Calcium Channel Blockers on the Female Genital Tract
Authors: Forman Axel , Andersson Karl‐Erik , Maigaard Svend
Published: July 2010

Abstract:Contractile activity and vascular resistance in the female genital tract are influenced by several smooth muscle tissues with individual mechanisms for control of mechanical activation. Calcium channel blockers have potent relaxant effects on preparations of human myometrium. The myometrial arteries utilize multiple sources of calcium for contractile activation, and excitation‐contraction coupling in isolated vessels from non‐pregnant uteri seems comparatively less sensitive to nifedipine than in corresponding myometrial preparations. Contractile activation of myometrial and placental arteries at term is inhibited by nitrendipine and nifedipine. Human oviductal smooth muscle depends on superficially bound calcium for mechanical activation, but only phasic contractions can be abolished by nifedipine, while tonic contractions induced by various agents are more resistant to the calcium channel blocker. Menstrual uterine contractions and pain are effectively counteracted by nifedipine in normal and dysmenorrhoeic women. Such therapy may represent an alternative principle in the treatment of dysmenorrhea. Nifedipine has potent relaxant effects on the mid‐term pregnant and the post‐partum uterus and calcium channel blockers may prove useful in the treatment of premature labor. Nifedipine and related compounds may further show effective in the treatment of pregnancy‐associated hypertension. Whether such treatment in late pregnancy involves maintained or even improved placental perfusion could be assumed from in vitro data but needs further studies.
Calcium Channel Blockers and Motility Disorders of the Esophagus
Authors: Andersson Karl‐Erik
Published: July 2010

Abstract: In animal experiments, esophageal smooth muscle, including the lower esophageal sphincter (LES) has been shown to be dependent on extracellular calcium both for tone and agonist induced contractions. Calcium channel blockers (CCB) suppress contractile activity, and block both resting and stimulated calcium influx. In normal man as well as in patients with hyper‐contractility disorders of the esophagus, such as achalasia and diffuse esophageal spasm, CCBs have been shown to reduce LES pressure and esophageal contractions, and also to cause symptomatic improvement. Controlled clinical trials on their effectiveness are lacking, but the therapeutic principle seems promising.
Nitrate tolerance in angina pectoris
Authors: Nordlander Rolf
Published: July 2010

Abstract: A review of the current literature concerning development of nitrate tolerance in the treatment of angina pectoris suggests that:

development of nitrate tolerance is a clinical reality

development of tolerance do not seem to differ for nitroglycerin, isosorbidedinitrate or isosorbide‐5‐mononitrate

a high nitrate dose seems to be more likely to induce tolerance

a nitrate free interval during some part of the day or the night seems to restore vascular responsiveness

by optimal use of different nitrate formulations the problem with development of tolerance may be reduced
Development of tolerance to nitrate therapy in chronic congestive heart failure
Authors: Swedberg Karl
Published: July 2010

Abstract: In several studies the nitrate effects on central hemodynamics during less than 24 hours have been evaluated in heart failure. Higher doses than in angina have been used. A pronounced response is seen acutely. An attenuation has been reported after 12–24 hours. A relation to continuous (intravenous, transdermal) administration of nitroglycerin has been proposed, but it is not clear. During chronic treatment with ISDN a tolerance is not obvious within 12 weeks. The heart failure patient has a different neurohumoral situation compared to angina patients. This could be one reason for differences in tolerance development during nitrate therapy.
Non‐invasive techniques used to monitor peripheral circulatory changes induced by nitroglycerin
Authors: Lindblad Lars Erik
Published: July 2010

Abstract: The antianginal effect of nitroglycerin is mainly mediated by its pronounced effects on peripheral vessels. These include an increased venous distensibility as well as a dilating effect on large arteries, a decreased arterial stiffness and an increased muscular and skin blood flow. These changes have been used to monitor and to assess the effects of various nitroglycerin preparations in numerous studies. The most frequently used techniques to demonstrate peripheral effects of nitroglycerin are summarized.
SERUM TRACE ELEMENTS DURING CHEMOTHERAPY FOR ACUTE MYELOGENOUS LEUKEMIA
Authors: Beguin Y. , Weber G. , Delbrouck J.M. , Roelandts I. , Robaye G. , Bury J. , Fillet G.
Published: July 2010

Abstract Serum trace elements were measured serially during 27 chemotherapeutic episodes in 22 patients undergoing chemotherapy for acute myelogenous leukemia. Serum copper, zinc, selenium and bromine were measured twice weekly by PIXE for a period of 3–20 weeks. Serum bromine dropped dramatically to very low values during the weeks following chemotherapy and returned slowly to subnormal values only after a few months. Serum zinc sharply decreased in cases of life‐threatening infection and patients with persisting low values generally went to death. Serum copper followed fibrinogen evolution with fairly good accordance, while serum selenium showed less systematic effects.
Sever's injury; treat it with a heel cup: a randomized, crossover study with two insole alternatives
Authors: Perhamre S. , Lundin F. , Norlin R. , Klässbo M.
Published: July 2010

Sever's injury (apophysitis calcanei) is considered to be the dominant cause of heel pain among children. Common advice is to reduce physical activity. However, our previous study showed that application of insoles reduced pain in Sever's injury without having to reduce physical activity. The purpose of this study was to test which of the two insoles, the heel wedge or the heel cup, provided best pain relief during sport activity in boys with Sever's injury (n=51). There was a crossover design in the first randomized part of the study. In the second part, the boys, 9–14 years, chose which insole they preferred. There was a reduction in odds score for pain to a fifth (a reduction of 80%) for the cup compared with the wedge (P<0.001). When an active choice was made, the heel cup was preferred by >75% of the boys. All boys maintained their high level of physical activity throughout. At 1‐year follow‐up, 22 boys still used an insole and 19 of them reported its effect on pain as excellent or good (n=41).
Early E‐modulus of healing Achilles tendons correlates with late function: Similar results with or without surgery
Authors: Schepull T. , Kvist J. , Aspenberg P.
Published: July 2010

Non‐operative treatment of Achilles tendon ruptures is associated with an increased risk of rerupture. We hypothesized that this is due to inferior mechanical properties during an early phase of healing, and performed a randomized trial, using a new method to measure the mechanical properties. Tantalum markers were inserted in the tendon stumps, and tendon strain at different loadings was measured by stereo‐radiography (Roentgen stereophotogrammetric analysis) at 3, 7 and 19 weeks and 18 months after injury. Thirty patients were randomized to operative or non‐operative treatment. The primary out‐come variable was an estimate for the modulus of elasticity at 7 weeks. Strain per force, cross‐sectional area and tendon elongation were also measured. The functional outcome variable was the heel‐raise index after 18 months. There was no difference in the mean modulus of elasticity or other mechanical or functional variables between operative and non‐operative treatments at any time‐point, but strain per force at 7 and 19 weeks had a significantly larger variation in the non‐operative group. This group, therefore, might contain more outliers with poor healing. The modulus of elasticity at 7 weeks correlated with the heel‐raise index after 18 months in both treatment groups (r2=0.75; P=0.0001). This correlation is an intriguing finding.
Knee laxity after complete anterior cruciate ligament tear: a prospective study over 15 years
Authors: Neuman P. , Kostogiannis I. , Fridén T. , Roos H. , Dahlberg L. E. , Englund M.
Published: July 2010

There is limited knowledge of knee laxity in the long term after a complete anterior cruciate ligament (ACL) tear treated without ACL reconstruction. The aim of this study was (1) to describe the clinical course of knee laxity after a complete ACL tear over 15 years, and (2) to study the association between knee laxity and meniscal injuries and the development of knee osteoarthritis (OA). We studied 100 consecutive subjects [mean (SD) age 26 (8) years] presenting with acute ACL injury prospectively. The initial treatment in all subjects was knee rehabilitation without reconstructive surgery. The subjects were examined with Lachman's and pivot‐shift tests at baseline, 6 weeks, 3 months, 1 year, 3 years and 15 years after the injury. Sagittal knee laxity was also evaluated with the KT‐1000 arthrometer at the 15‐year follow‐up. During follow‐up, 22 subjects were ACL reconstructed due to unacceptable knee instability. There was only a mild remaining knee laxity [median Lachman grade and pivot‐shift test value of 1 on a 4‐grade scale (0–3)] after 15 years in subjects treated without primary ACL reconstruction. Knees with higher anterior sagittal knee laxity 3 months after the injury had a worse long‐term outcome with respect to meniscal injuries and knee OA development.
Lipodystrophy – a sign for metabolic syndrome in patients of the HIV‐HEART study
Authors: Potthoff Anja , Brockmeyer Norbert H. , Gelbrich Götz , Neuhaus Kathrin , Esser Stefan , Reinsch Nico , Hower Martin , Mostardt Sarah , Neumann Anja , Neumann Till ,   For the Competence Center Cardiac Insufficiency and the Competence Network HIV/AIDS
Published: July 2010

Background: After the introduction of antiretroviral therapy, the life expectancy of HIV patients has increased to more than 30 years after initial diagnosis. Cardiovascular disease now is an important cause of death in HIV‐infected patients.

Patients and Methods: In the multicenter, prospective HIV‐HEART study, 222 (38 %) patients suffered from lipodystrophy. Women were more often affected than men (41.5 % vs. 25.3 %). Patients with lipodystrophy were on average 5 years older and had been infected longer (10.4 vs. 6.6 years) then patients without lipodystrophy. Results: Lipodystrophy in HIV patients was a clinical sign of cardiovascular risk factors like hyperlipidemia (total cholesterol 19 mg/dl higher, HDL 2.8 mg/dl lower, triglycerides 53 mg/dl higher) and type 2 diabetes (11.3 % vs. 2.8 %). Patients with lipodystrophy were more likely to be co‐infected with hepatitis B (34.7 % vs. 28.8 %, p = 0.122) or C (13.1 % vs. 9.3 %, p = 0.16) than patients without lipodystrophy. The quality of life was reduced in patients with lipodystrophy. In 6 of 8 scales of the SF‐36 questionnaire, patients with lipodystrophy had lower scores.

Conclusions: Lipodystrophy syndrome is an early warning system for a number of illnesses which reduce life expectancy. Dermatologists must help insure that HIV‐infected patients receive treatment for these disorders.
G‐quadruplex nucleic acids and human disease
Authors: Wu Yuliang , Brosh Robert M.
Published: July 2010

Alternate DNA structures that deviate from B‐form double‐stranded DNA such as G‐quadruplex (G4) DNA can be formed by sequences that are widely distributed throughout the human genome. G‐quadruplex secondary structures, formed by the stacking of planar quartets composed of four guanines that interact by Hoogsteen hydrogen bonding, can affect cellular DNA replication and transcription, and influence genomic stability. The unique metabolism of G‐rich chromosomal regions that potentially form quadruplexes may influence a number of biological processes including immunoglobulin gene rearrangements, promoter activation and telomere maintenance. A number of human diseases are characterized by telomere defects, and it is proposed that G‐quadruplex structures which form at telomere ends play an important role in telomere stability. Evidence from cellular studies and model organisms suggests that diseases with known defects in G4 DNA helicases are likely to be perturbed in telomere maintenance and cellular DNA replication. In this minireview, we discuss the connections of G‐quadruplex nucleic acids to human genetic diseases and cancer based on the recent literature.
The primary care nurse practitioner and cancer survivorship care
Authors: Cooper Joanna M. , Loeb Susan J. , Smith Carol A.
Published: July 2010

Purpose: To examine the important role that primary care nurse practitioners (NPs) have in providing long‐term surveillance and health maintenance for breast, prostate, and colorectal cancer survivors throughout the continuum of cancer care.

Data sources: MEDLINE, CINAHL, MD‐Consult, and Cochrane's databases were utilized with the inclusion of primary research and critical research reviews from January 1995 through March 2008. Select organizational websites were also cited.

Conclusions: Cancer patients experience changes in the focus of their care when management shifts from the treatment of cancer to management of treatment side effects and outcomes, to survivorship care, and to secondary cancer treatment. NPs have a strong impact on cancer survivorship care by serving in various roles and settings throughout the cancer trajectory to improve patient outcomes.

Implications for practice: Cancer survivorship care expands beyond specialty settings, into primary care. NPs have a key role in ensuring continuity of care for patients with cancer. Models of care that promote continuity and high quality of care for patients with cancer include the shared‐care and nurse‐managed health center models. The formal collaborative plan of care is essential in long‐term cancer survivorship care.
An innovative approach to standardizing heart failure care: The heart failure support team
Authors: Manning Stacey , Wendler M. Cecilia , Baur Karen
Published: July 2010

Purpose: The purpose of this project was to determine if a comprehensive program of heart failure support using a three‐step approach during acute care led by an advanced practice nurse (APN) improves outcomes. The goal was to implement Centers for Medicare and Medicaid Services (CMS) appropriate care recommendations for all patients with heart failure, reducing variation, and increasing quality of care.

Data sources: Retrospective hospital chart reviews demonstrated patients were being admitted with one diagnosis, but ultimately discharged under the heart failure diagnosis‐related group (DRG). Because these patients had not been identified as heart failure patients during hospitalization, we discovered an opportunity to improve care through program development.

Conclusions: Once this approach was implemented consistently and sustained, we achieved near‐perfect CMS scores. Composite quality scores for patients with heart failure improved from 82.12% to 100%. Electronic tracking of patients after referrals from multiple sources became the keystone of the program, facilitating early identification, teaching, and ongoing patient monitoring.

Implications for practice: A comprehensive approach to heart failure support using a team is recommended. However, research is needed to determine if this approach improves quality of life, hospital readmission rates, or lengths of stay for this vulnerable population.
Does familiarity breed respect? Physician attitudes toward nurse practitioners in a medically underserved state
Authors: Street Debra , Cossman Jeralynn S.
Published: July 2010

Purpose: An evolving primary care environment underscores the importance of physician and nurse practitioner (NP) interactions. We analyze how physician characteristics and close working relationships (presence of NPs in practice) influence physicians’ attitudes toward NPs.

Data sources: Bivariate analyses of 2007–2008 Missisisppi Physician Workforce Study survey data (response rate 23.3%) identified Mississippi physician characteristics associated with having NPs in practices and discrete NP‐attitudinal items. Generalized physician attitudes toward NPs were modeled using multivariate regression.

Conclusions: Generalists, physicians in public sector employment and physicians in larger practices are more likely to work in practices that also include NPs. Physicians working with NPs are somewhat younger than those who do not. Regression analysis indicates that male physicians had less‐positive attitudes toward NPs, while physicians who practice alongside NPs and who have been in practice longer have the most positive generalized attitudes toward NPs.

Implications for practice: Physicians who work in the same practice with NPs have more positive attitudes toward them. However, regardless of work arrangements, MS physicians are reluctant for NPs to practice independently. Physicians with early collaborative training with NPs may have more positive attitudes, but even such exposure will not necessarily lead physicians to support NPs’ independent practice.
Transsexual primary care
Authors: Jenner Christopher O.
Published: July 2010

Purpose: Transsexual presentations in primary care stress mainstream health care physical resources, institutional organization, and the cultural flexibility of providers and interdisciplinary staff. This article describes the ethical landscape, examines gender identity culture, and considers gender reassignment physiology. Nurse practitioners are challenged to advocate for this population.

Data sources: Sources for the discussion derive from published institutional guidelines, institutional and civic policies, web‐based information in the public domain, and professional journal articles.

Conclusions: Advocacy for cultural sensitivity, institutional policy change,and professional integrity will determine healthcare quality for this population. Advocacy for cultural awareness and institutional change has begun in larger institutions and metropolitan areas, but is necessary across primary care settings.

Implications for practice: Caring for transsexuals requires knowledge of anatomical reassignments, hormonal therapy effects, and cultural sensitivities particular to the gender identity community. Healthcare screening and physical exam modifications for these presentations require forethought and appropriate adjustments.
Canine dilated cardiomyopathy: a retrospective study of prognostic findings in 367 clinical cases
Authors: Martin M. W. S. , Stafford Johnson M. J. , Strehlau G. , King J. N.
Published: July 2010

Objective: To review the association between clinical signs and diagnostic findings and the survival time of dogs with dilated cardiomyopathy (DCM), and any influence of treatment prescribed.

Methods: A retrospective observational study of 367 dogs with DCM. Survival times until death or euthanasia for cardiac reasons were analysed using the Kaplan–Meier method plus univariate and multivariate Cox proportional hazards models. Two‐tailed P values less than 0·05 were considered statistically significant.

Results: In the multivariate model, left ventricular diameter (LVDs)‐index (P=0·0067), presence of pulmonary oedema on radio‐graphy (P=0·043), presence of ventricular premature complexes (VPCs) (P=0·0012), higher plasma creatinine (P=0·0002), lower plasma protein (P=0·029) and great Dane breed (P=0·0003) were negatively associated with survival. Most dogs were treated with angiotensin‐converting enzyme inhibitors (93%) or furosemide (86%), and many received digoxin (50%) and/or pimobendan (30%). Thirteen dogs were lost to follow‐up. No conclusions could be made in this study on the association between use of drugs and survival.

ClinicalSignificance: The LVDs‐index was the single best variable for assessing the prognosis in this group of dogs with DCM. Other variables that were negatively associated with survival were presence of pulmonary oedema on radiography, presence of VPCs, higher plasma creatinine, lower plasma protein and great Dane breed.
Induction of Phlorotannins During UV Exposure Mitigates Inhibition of Photosynthesis and DNA Damage in the Kelp Lessonia nigrescens
Authors: Gómez Ivan , Huovinen Pirjo
Published: July 2010

Phlorotannins of brown algae are multifunctional compounds with putative roles in herbivore deterrence, antioxidation and as primary cell wall components. Due to their peripheral localization and absorption at short wavelengths, a photoprotective role is suggested. We examined the induction of phlorotannins by artificial UV radiation in the intertidal kelp Lessonia nigrescens and whether they attenuate the inhibition of photosynthesis and DNA damage, two major detrimental effects of UV. The soluble and cell wall‐bound fractions of phlorotannins were quantified in blades collected in summer and winter. Major findings were that (1) the synthesis of phlorotannins (both forms) was induced by UV only in summer; (2) the induction was fast (within 3 days); and (3) there was a positive relationship between of the contents of insoluble phlorotannins and the suppression of photoinhibition and DNA damage, measured as formation of cyclobutane pyrimidine dimers and 6‐4 photoproducts. Overall, the photoprotective role of phlorotannins appears to respond to an interplay between the external UV stimulus, seasonal acclimation and intrinsic morpho‐functional processes. In summer, when algae are naturally exposed to high UV irradiances, soluble phlorotannins are induced, while their transition to insoluble phlorotannins could be related with the growth requirements, as active blade elongation occurs during this season.
Effect of age on anterior chamber angle configuration in Asians determined by anterior segment optical coherence tomography; clinic‐based study
Authors: Cheon Mi Hyun , Sung Kyung Rim , Choi Eun Hee , Kang Sung Yong , Cho Jung Woo , Lee Suhwan , Kim Jae Yong , Tchah Hung Won , Kook Michael S.
Published: July 2010

Acta Ophthalmol. 2010: 88: e205–e210

Purpose:  To evaluate the distribution of anterior chamber angle (ACA) parameters and to assess association of these parameters with age in Asian subjects.

Methods:  Four hundred and thirty‐nine consecutive Korean subjects aged from 30 to 89 were enrolled from a university clinic. All participants were scanned using anterior segment optical coherence tomography (AS‐OCT, Visante, version 2.0). We measured ACA parameters such as anterior chamber depth (ACD), angle opening distance at 500 and 750 μm (AOD500,750), angle recess area at 500 and 750 μm (ARA500,750), trabecular iris space area at 500 and 750 μm (TISA500,750), and determined age‐related changes in these parameters with use of a linear mixed effect model that adjusted for gender, axial length, intraocular pressure, and keratometry data. Slopes of ACA parameters as a function of age were determined. For various AS‐OCT parameters, the normalized slope was calculated by dividing the slope by the mean value.

Results:  All analysed ACA parameters decreased with age in both nasal and temporal quadrants. Axial length and keratometry data were significant covariates for ACA changes. The slopes of ACD were −0.02396 mm/year, AOD500, ARA500, and TISA500 measured at the temporal angle were −0.00634 mm/year, −0.0019 mm2/year, and −0.00177 mm2/year, respectively. There was no age‐dependent difference in central corneal thickness (p value; 0.4597) Based on the normalized slopes, the AOD showed the steepest slope at both temporal and nasal sectors.

Conclusion:  All ACA parameters assessed by AS‐OCT, which accounted for other ocular biometric parameters, showed significant negative slopes with increasing age. These results should be considered when assessing changes in the anterior chamber over time.
Constraints to Water Transfers in Unadjudicated Basins: The Middle Rio Grande as a Case Study
Authors: Pease Michael
Published: July 2010

Water reallocations are contentious under the best of circumstances. When a basin lacks a comprehensive adjudication of water rights, the levels of legal and economic complexity and controversy intensify. This paper evaluates the Middle Rio Grande, a region of New Mexico that would seem an ideal location for water markets as the need to reallocate water between existing uses is high. Due to the lack of an adjudication, and other complicating factors such as the Endangered Species Act, proposed transfers require a complex evaluation system created by the New Mexico Office of the State Engineer. Even with this evaluation system in place, many questions linger about the validity of transfers and their larger impacts.
Progress in Understanding Factors Governing the Sodium Manganese Ferrite Thermochemical Cycle
Authors: Alvani C. , Bellusci M. , La Barbera A. , Padella F. , Seralessandri L. , Varsano F.
Published: July 2010

The mixed sodium manganese ferrite thermochemical cycle for sustainable hydrogen production is reviewed. Both the hydrogen production step and the reaction that leads to the regeneration of initial reactants are described as multistep reactions. The chemical cyclability of the reactive system has been demonstrated at 750°C.
Analysis of Wind Turbine Vibrations Based on SCADA Data
Authors: Kusiak Andrew , Zhang Zijun
Published: July 2010

Vibrations of a wind turbine have a negative impact on its performance. Mitigating this undesirable impact requires knowledge of the relationship between the vibrations and other wind turbine parameters that could be potentially modified. Three approaches for ranking the impact importance of measurable turbine parameters on the vibrations of the drive train and the tower are discussed. They include the predictor importance analysis, the global sensitivity analysis, and the correlation coefficient analysis versed in data mining and statistics. To decouple the impact of wind speed on the vibrations of the drive train and the tower, the analysis is performed on data sets with narrow speed ranges. Wavelet analysis is applied to filter noisy accelerometer data. To exclude the impact malfunctions on the vibration analysis, the data are analyzed in a frequency domain. Data-mining algorithms are used to build models with turbine parameters of interest as inputs, and the vibrations of drive train and tower as outputs. The performance of each model is thoroughly evaluated based on metrics widely used in the wind industry. The neural network algorithm outperforms other classifiers and is considered to be the most promising approach to study wind turbine vibrations.
A Direct Steam Generation Solar Power Plant With Integrated Thermal Storage
Authors: Birnbaum Jürgen , Eck Markus , Fichtner Markus , Hirsch Tobias , Lehmann Dorothea , Zimmermann Gerhard
Published: July 2010

For the future market potential of parabolic trough power plants with direct steam generation (DSG), it is beneficial to integrate a thermal storage system. Heat storage media based on phase change materials offer heat transfer at constant temperatures needed for the evaporation process. Different options for a plant layout are presented and discussed. The interactions between the three subsystems—solar field, power block, and thermal storage—are analyzed, and boundary conditions arising from the thermal storage system are identified. Compared with a system without storage the number of operating points increases significantly since different combinations of storage charge and discharge operations go along with a varying power output of the solar field. It is shown that the large number of theoretical operating points can be reduced to a subset with practical relevance. Depending on the live steam parameters a reheat is necessary within the power block. Compared with parabolic trough fields with a single phase heat transfer medium such as oil, a special heat exchanger configuration is needed for a DSG plant. Different alternatives based on available technologies are presented and evaluated.
Two-Step Optimization for Wind Turbine Blade With Probability Approach
Authors: Lee Ki-Hak , Kim Kyu-Hong , Lee Dong-Ho , Lee Kyung-Tae , Park Jong-Po
Published: July 2010

A horizontal-axis wind turbine blade is designed using two step optimization procedures with probability approach. For the efficient management of the multiple design variables required for the blade design, the design procedure is divided into two optimization steps. In step 1, the diameter and rotating speed of a blade are determined and design points are extracted from the design space. In step 2-1, blade shapes are optimized by using the strip theory with the minimum energy loss method. The capacity factor and the cost model for each optimized blade shape are calculated in steps 2-2 and 2-3, respectively. To find the global optimum point in the design space, the space is modified into a highly possible region through the use of the probability approach.
Verification of Predicted Knee Replacement Kinematics During Simulated Gait in the Kansas Knee Simulator
Authors: Halloran Jason P. , Clary Chadd W. , Maletsky Lorin P. , Taylor Mark , Petrella Anthony J. , Rullkoetter Paul J.
Published: July 2010

Evaluating total knee replacement kinematics and contact pressure distributions is an important element of preclinical assessment of implant designs. Although physical testing is essential in the evaluation process, validated computational models can augment these experiments and efficiently evaluate perturbations of the design or surgical variables. The objective of the present study was to perform an initial kinematic verification of a dynamic finite element model of the Kansas knee simulator by comparing predicted tibio- and patellofemoral kinematics with experimental measurements during force-controlled gait simulation. A current semiconstrained, cruciate-retaining, fixed-bearing implant mounted in aluminum fixtures was utilized. An explicit finite element model of the simulator was developed from measured physical properties of the machine, and loading conditions were created from the measured experimental feedback data. The explicit finite element model allows both rigid body and fully deformable solutions to be chosen based on the application of interest. Six degrees-of-freedom kinematics were compared for both tibio- and patellofemoral joints during gait loading, with an average root mean square (rms) translational error of 1.1 mm and rotational rms error of 1.3 deg. Model sensitivity to interface friction and damping present in the experimental joints was also evaluated and served as a secondary goal of this paper. Modifying the metal-polyethylene coefficient of friction from 0.1 to 0.01 varied the patellar flexion-extension and tibiofemoral anterior-posterior predictions by 7 deg and 2 mm, respectively, while other kinematic outputs were largely insensitive.
Structured Tree Impedance Outflow Boundary Conditions for 3D Lung Simulations
Authors: Comerford Andrew , Förster Christiane , Wall Wolfgang A.
Published: July 2010

In this paper, we develop structured tree outflow boundary conditions for modeling the airflow in patient specific human lungs. The utilized structured tree is used to represent the nonimageable vessels beyond the 3D domain. The coupling of the two different scales (1D and 3D) employs a Dirichlet–Neumann approach. The simulations are performed under a variety of conditions such as light breathing and constant flow ventilation (which is characterized by very rapid acceleration and deceleration). All results show that the peripheral vessels significantly impact the pressure, however, the flow is relatively unaffected, reinforcing the fact that the majority of the lung impedance is due to the lower generations rather than the peripheral vessels. Furthermore, simulations of a hypothetical diseased lung (restricted flow in the superior left lobe) under mechanical ventilation show that the mean pressure at the outlets of the 3D domain is about 28% higher. This hypothetical model illustrates potential causes of volutrauma in the human lung and furthermore demonstrates how different clinical scenarios can be studied without the need to assume the unknown flow distribution into the downstream region.
Measurements of the Static Friction Coefficient Between Bone and Muscle Tissues
Authors: Shacham Sharon , Castel David , Gefen Amit
Published: July 2010

This study aimed at measuring the static coefficient of friction (μ) between bone and skeletal muscle tissues in order to support finite element (FE) modeling in orthopaedic and rehabilitation research, where such contact conditions need to be defined. A custom-made friction meter (FM) that employs the load cell and motion-controlled loading arm of a materials testing machine was designed for this study. The FM was used to measure μ between fresh ulna bones and extensor muscles surrounding the ulna, which were harvested from five young adult pigs. Mean bone-muscle μ were between 0.36 and 0.29, decreased with the increase in loads applied on the bone (p<0.05) and plateaued at a mean ∼0.3 for loads exceeding 4 N. Hence, for FE modeling of bone-muscle contacts through which loads with magnitudes of kgs to 10s-of-kgs are transferred, assuming μ of ∼0.3 appears to be appropriate.
Fiber Optic Microneedles for Transdermal Light Delivery: Ex Vivo Porcine Skin Penetration Experiments
Authors: Kosoglu Mehmet A. , Hood Robert L. , Chen Ye , Xu Yong , Rylander Marissa Nichole , Rylander Christopher G.
Published: July 2010

Shallow light penetration in tissue has been a technical barrier to the development of light-based methods for in vivo diagnosis and treatment of epithelial carcinomas. This problem can potentially be solved by utilizing minimally invasive probes to deliver light directly to target areas. To develop this solution, fiber optic microneedles capable of delivering light for either imaging or therapy were manufactured by tapering step-index silica-based optical fibers employing a melt-drawing process. Some of the microneedles were manufactured to have sharper tips by changing the heat source during the melt-drawing process. All of the microneedles were individually inserted into ex vivo pig skin samples to demonstrate the feasibility of their application in human tissues. The force on each microneedle was measured during insertion in order to determine the effects of sharper tips on the peak force and the steadiness of the increase in force. Skin penetration experiments showed that sharp fiber optic microneedles that are 3 mm long penetrate through 2 mm of ex vivo pig skin specimens. These sharp microneedles had a minimum average diameter of 73 μm and a maximum tip diameter of 8 μm. Flat microneedles, which had larger tip diameters, required a minimum average diameter of 125 μm in order to penetrate through pig skin samples. Force versus displacement plots showed that a sharp tip on a fiber optic microneedle decreased the skin’s resistance during insertion. Also, the force acting on a sharp microneedle increased more steadily compared with a microneedle with a flat tip. However, many of the sharp microneedles sustained damage during skin penetration. Two designs that did not accrue damage were identified and will provide a basis of more robust microneedles. Developing resilient microneedles with smaller diameters will lead to transformative, novel modes of transdermal imaging and treatment that are less invasive and less painful for the patient.
MIT OpenCourseWare: Unlocking Knowledge, Empowering Minds
Authors: d'Oliveira Cecilia , Carson Stephen , James Kate , Lazarus Jeff
Published: July 2010

A collection of more than 2000 course syllabi, lecture notes, assignments, and exams is provided free of charge.
Microbial Biosynthesis of Alkanes
Authors: Schirmer Andreas , Rude Mathew A. , Li Xuezhi , Popova Emanuela , del Cardayre Stephen B.
Published: July 2010

Toward Alkane Synthesis

Alkanes are major components of fossil fuels, and synthesis of alkanes remains a challenge in the conversion of renewable raw materials to fuels. Even though diverse organisms synthesize alkanes, synthesis pathways have remained elusive. Now

Schirmer
et al.

(p.
559
) describe an alkane biosynthesis pathway in cyanobacteria that converts intermediates of fatty acid metabolism to alkanes and alkenes. Heterologous expression of the biosynthetic genes resulted in production of alkanes in
Escherichia coli
. This pathway is likely to be a valuable tool in the production of biofuels.
Steric Effects in the Chemisorption of Vibrationally Excited Methane on Ni(100)
Authors: Yoder Bruce L. , Bisson Régis , Beck Rainer D.
Published: July 2010

Tilting Toward Reaction

Collisions between molecules and metal surfaces underlie many of the catalytic pathways that transform natural feedstocks into fuels and commodity chemical compounds. One such reaction, in which nickel strips hydrogen from methane, depends on whether the methyl C-H bonds are vibrating just before the molecule strikes the surface.

Yoder
et al.

(p.
553
) now delve deeper into this system. By aligning incoming molecular samples using polarized infrared light, they show that the hydrocarbon reacts most readily when it is vibrating parallel, rather than perpendicular, to the surface.
Copper Mine Threatens Ancient Monastery in Afghanistan
Authors: Lawler Andrew
Published: July 2010

A Chinese company intends to blow up an ancient Buddhist monastery south of Kabul to make way for a massive copper mine. The plan has sparked outrage among Afghan and French archaeologists.
Is China's Riskiest Volcano Stirring Or Merely Biding Its Time?
Authors: Stone Richard
Published: July 2010

Last month, a South Korean geologist declared that a 2744-meter-tall volcano on the border of China and North Korea is showing signs of waking from a century-long slumber. But Chinese volcanologists discount the threat and insist that the volcano is quiet.
Money Woes Cast Shadow Over HIV/AIDS, But Ray of Light in South Africa
Authors: Cohen Jon
Published: July 2010

At the 18th International AIDS Conference last week, the South African government—which from 1999 to 2008 had a president who questioned whether HIV even caused disease and a health minister who advocated lemons and garlic for treatment—declared that "Today, we are guided by science."
Europe Tries to Save Its Eels
Authors: Vogel Gretchen
Published: July 2010

New national efforts to save the European eel face political and scientific challenges.
Effects of Lactobacilli on Cytokine Expression by Chicken Spleen and Cecal Tonsil Cells
Authors: Brisbin Jennifer T. , Gong Joshua , Parvizi Payvand , Sharif Shayan
Published: July 2010

Lactobacillus acidophilus
,
Lactobacillus reuteri
, and
Lactobacillus salivarius
are all normal residents of the chicken gastrointestinal tract. Given the interest in using probiotic bacteria in chicken production and the important role of the microbiota in the development and regulation of the host immune system, the objective of the current study was to examine the differential effects of these bacteria on cytokine gene expression profiles of lymphoid tissue cells. Mononuclear cells isolated from cecal tonsils and spleens of chickens were cocultured with one of the three live bacteria, and gene expression was analyzed via real-time quantitative PCR. All three lactobacilli induced significantly more interleukin 1β (IL-1β) expression in spleen cells than in cecal tonsil cells, indicating a more inflammatory response in the spleen than in cecal tonsils. In cecal tonsil cells, substantial differences were found among strains in the capacity to induce IL-12p40, IL-10, IL-18, transforming growth factor β4 (TGF-β4), and gamma interferon (IFN-γ). In conclusion, we demonstrated that
L. acidophilus
is more effective at inducing T-helper-1 cytokines while
L. salivarius
induces a more anti-inflammatory response.