bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of different anaesthetics on pro-inflammatory cytokine expression in rat spleen
Authors: Bette M. , Schlimme S. , Mutters R. , Menendez S. , Hoffmann S. , Schulz S.
Published: June 2004

We examined the effect of five anaesthetic drugs commonly used in laboratory animal research (tribromoethanol, ketamine/xylazine, chloral hydrate, pentobarbital, and urethane) on the expression of four pro-inflammatory cytokines. The anaesthetic agents were applied at dosages normally used for deep surgical anaesthesia. Semiquantitative image analysis of interleukin (IL)-1β, IL-2, IL-6, and tumour necrosis factor alpha (TNFα) mRNA expression in the spleen of male Wistar rats 4 h after application of the anaesthetic drugs showed that these had moderate immunomodulatory effects. Ketamine/xylazine, chloral hydrate, and pentobarbital enhanced the basal expression of IL-1β and IL-6 mRNA in rat spleen, while urethane reduced splenic IL-1β mRNA expression. Tribromoethanol, ketamine/ xylazine, and urethane reduced the basal TNFα mRNA levels, whereas TNFα mRNA expression was unaffected by chloral hydrate and by pentobarbital. The data demonstrate that these anaesthetics have slight, but significant, effects on the basal immune status of rats.
A replacement for methoxyflurane (Metofane) in open-circuit anaesthesia
Authors: Itah Refael , Gitelman Inna , Davis Claytus
Published: June 2004

Methoxyflurane (Metofane) has been widely used as an open-circuit anaesthetic in small laboratory animals for several decades. Its low vapour pressure and high blood solubility have permitted its use in convenient and simple drop-chamber/nose-cone setups. Recently, following the decision by the primary manufacturer to discontinue production, it has become increasingly difficult to obtain methoxyflurane. We describe here a simple and effective adaptation of isoflurane, an excellent inhalation anaesthetic, to open-circuit drop-chamber/nose-cone anaesthesia. It was found that the vapour concentration of isoflurane could be continuously varied by dissolving the anaesthetic in propylene glycol and that a 20% solution produced effective anaesthesia such that in adult mice, 2 ml of 20% isoflurane in propylene glycol induced anaesthesia within 2 min in a one-litre drop chamber. Furthermore, anaesthesia maintenance with 20% isoflurane was tested in two sets of mice. In one set, surgical plane anaesthesia was maintained for 10 min in a head chamber. After removal of the chamber, the animals awoke within one minute and recovered without any indication of post-anaesthetic distress. The second set contained pregnant mice; here anaesthesia was maintained for between 10 and 12 min, during which laparotomy, exposure of one uterine horn, intrauterine injection and wound closure were completed. The recovery from anaesthesia was also within a minute and with no signs of distress. Healthy litters were delivered after a normal gestation. This isoflurane/propylene glycol procedure is simple, effective and humane, and is a good substitute for methoxyflurane.
Behavioural assessment of the effects of tumour growth in rats and the influence of the analgesics carprofen and meloxicam
Authors: Roughan John V. , Flecknell Paul A. , Davies Barry R.
Published: June 2004

Very little is known concerning the occurrence of pain in cancer research models. We wished to establish whether a behaviour-based approach, originally developed to assess postoperative pain, could be used to determine positive effects of the analgesics carprofen and meloxicam in rats that might be experiencing pain during tumour development in an orthotopic model of bladder cancer. An invasive but non-metastatic rat bladder cancer cell line was surgically implanted into the bladder wall of 57 inbred Fisher344 rats. The rats underwent daily clinical assessments. When clinical signs consistent with chronic pain were apparent, behavioural data were collected from 44 animals during 2×10 min periods, immediately before and one hour after a subcutaneous injection of either physiological saline (0.9%; 0.2 ml/100 g), carprofen (5 mg/kg) or meloxicam (2 mg/kg). Treatment-associated behaviour changes were then compared between groups. The lack of active behaviour, both before and after each treatment, was consistent with established clinical signs of pain. The rats were so inactive following the treatment that the behavioural technique we had previously developed was of comparatively little use in determining either pain severity or analgesic efficacy. One very prominent effect, however, was an increase in ventral abdominal licking in the control (saline) group. As this was absent in rats given meloxicam or carprofen, and has previously been considered to indicate pain emanating from damaged tissue, it was concluded that the analgesic-treated rats gained at least some benefit from the drug treatments, but it was not possible to gauge the extent of this. Handling for examination or treatment may have intensified pain in rats in the control group, and so this should be avoided whenever possible. It is likely that post-surgical pain differs markedly from cancer pain, so a different set of behavioural markers may be needed to assess it effectively. More intensive behaviour monitoring may help to develop a suitable technique for detecting the onset of, and assess the severity of pain that may occur during tumour development.
Comparison of methods of temperature measurement in swine
Authors: Hanneman S. K. , Jesurum-Urbaitis J. T. , Bickel D. R.
Published: June 2004

The purpose of these experiments was to test the equivalence of pulmonary artery, urinary bladder, tympanic, rectal and femoral artery methods of temperature measurement in healthy and critically ill swine under clinical intensive care unit (ICU) conditions using a prospective, time series design. First, sensors were tested for error and sensitivity to change in temperature with a precision-controlled water bath and a laboratory-certified digital thermometer for temperatures 34-42°C. There was virtually no systematic (bias) or random (precision) error (<0.2°C). The bladder sensor had the slowest response time to change in temperature (105-120 s). Next, testing was done in an experimental porcine ICU in a non-profit research institution with four male, sedated, and mechanically ventilated domestic farm pigs. The in vivo experiments were conducted over periods of 41-168 h with temperatures measured every 1-5 s. The bladder, tympanic and rectal methods had unacceptable bias (≥0.5°C) and/or precision (≥0.2°C). Response time varied from 7 s with the femoral artery method to 280 s (4.7 min) with the tympanic method. We concluded that equivalence of the methods was insufficient for them to be used interchangeably in the porcine ICU. Intravascular monitoring of core body temperature produces optimal measurement of porcine temperature under varying conditions of physiological stability.
Orthotopic transplantation of rat ovaries as a tool for strain rescue
Authors: Dorsch M. , Wedekind D. , Kamino K. , Hedrich H. J.
Published: June 2004

Spontaneous mutations in inbred strains provide valuable resources for new disease models. Unfortunately, these mutations may affect reproduction, which require considerable efforts in breeding management. We transplanted ovaries of such mutant rat strains orthotopically into ovariectomized premature coisogenic recipients. A reproductive cycle was established in each of the recipients within 5 to 6 weeks after transplantation. Moreover, one-third became pregnant and had litters an average of 3 months after transplantation. These experiments demonstrate that orthotopic transplantation of ovaries can be used in the management of subfertile rat colonies.
Testicular torsion and its effects on the spermatogenic cycle in the contralateral testis of the rat
Authors: Vigueras R. M. , Reyes G. , Rojas-Castañeda J. , Rojas P. , Hernández R.
Published: June 2004

The aim of the present study was to evaluate the effects of unilateral testicular torsion on the contralateral testis with respect to the stages of the cycle of the seminiferous epithelium (CSE). Fifty-five male Wistar rats, 60 days old, were used. The animals were divided into 11 groups. Groups 1-5 were subjected to unilateral testicular torsion from 3 to 48 h, followed by detorsion. Groups 6-10 had unilateral orchiectomies after unilateral testicular torsion for 3 to 48 h. Animals constituting group 11 served as the control sham-operated group. All animals were killed after 2 months. The percentage of affected tubules (tubules showing pathological changes) in the contralateral testis was estimated based on the CSE stages. In the torsion/detorsion group, the percentage of affected tubules was significantly greater (58.6%) than in torsion/orchiectomy group (48.0%). Stages VI-XI of the spermatogenic cycle were the most affected when compared with the rest of the stages in each experimental group ( P <0.05). These results show that stages VI-XI of the spermatogenic cycle, the stages associated with low antioxidant capacities, are the most sensitive to the effects of testicular torsion on the contralateral testis.
Septicaemia associated with an Aerococcus viridans infection in immunodeficient mice
Authors: Dagnæs-Hansen Frederik , Kilian Mogens , Fuursted Kurt
Published: June 2004

This report describes a case series of septicaemia caused by infection with Aerococcus viridans in immunodeficient NOD/LtSz- Prkdcscid (NOD/SCID) mice. During a period of 3 weeks more than 40 animals died or became ill with clinical signs of ruffled coat, weight loss, laboured breeding, and distended abdomen. At necropsy it was found that the animals displayed symptoms of sepsis with widespread abscesses in the liver, heart, lungs or pyogenic peritonitis. A Gram-positive coccus was isolated in pure culture from the abscesses or peritoneum from affected animals. According to phenotypic and phylogenetic characterization, the isolate was identified as A. viridans. This is the first report of a spontaneous outbreak of septicaemia caused by A. viridans infection in immunodeficient laboratory mice and we conclude that A. viridans should be considered as a pathogen in immunodeficient mice.
Prevalence of High C-Reactive Protein in Persons with Serum Lipid Concentrations within Recommended Values
Authors: Ajani Umed A , Ford Earl S , Mokdad Ali H
Published: June 2004

Background: C-Reactive protein (CRP) has been shown to be a strong predictor of coronary heart disease (CHD) and is being considered in cardiovascular disease risk assessment. The number of normolipidemic individuals who are eligible for evaluation of CRP in overall CHD risk assessment is not known.

Methods: We analyzed data from the National Health and Nutrition Examination Survey 1999–2000 and computed the prevalence of high CRP (>3 mg/L) among normolipidemic adults. We also computed the prevalence among individuals free of CHD and diabetes. In addition, we examined the prevalence stratified by body mass index.

Results: The prevalence of high CRP among those with lipid concentrations within recommended values ranged from 28.8% to 35.3%, depending on the lipid fraction examined. Exclusion of individuals with CHD or diabetes and those with CRP concentrations >10 mg/L reduced the prevalence range (23.1–27.1%). Prevalence increased with increasing body mass index.

Conclusions: In 2000, ∼12 million adults in the United States considered normolipidemic had high CRP concentrations. Additional studies to explore the role of CRP in cardiovascular disease risk assessment are needed.
Adverse Events Associated with Chemotherapy for Common Cancers
Authors: Adams Val R.
Published: June 2004

Neutropenia is a common and often dose‐limiting toxicity associated with chemotherapy. One way to decrease the severity of this adverse event is to use colony‐stimulating factors (CSFs) after chemotherapy. Colony‐stimulating factors are relatively expensive agents, and most institutions limit their use. Unfortunately, it is difficult to predict which patients are likely to develop neutropenia. An improved ability to predict this situation might help institutions and clinicians determine which patients need CSFs as adjunctive therapy. The efficacy of CSFs and how they may affect patient outcomes are discussed. In addition, a primary literature review on the toxicity associated with chemotherapy regimens used for common cancers is summarized. Knowing the toxicity of individual regimens may help clinicians identify patients needing adjunctive therapy or less toxic regimens. Any action that helps reduce the occurrence, or severity, of neutropenia in patients receiving chemotherapy would be beneficial and enhance the patient's quality of life.
Evaluation of Warfarin Initiation Regimens in Elderly Inpatients
Authors: O'Connell Mary Beth , Kowal Paul R. , Allivato Caren J. , Repka Tanya L.
Published: June 2004

Study Objective. To compare initial warfarin doses of 5 mg or below and doses above 5 mg in hospitalized elderly.

Design. Retrospective review of charts identified from computerized pharmacy records.

Setting. County teaching hospital.

Patients. Inpatients aged 65 years or older receiving at least three warfarin doses.

Intervention. We measured the time to first international normalized ratio (INR) of 2.0 or greater, bleeding complications, number of warfarin doses held, and vitamin K use.

Measurements and Main Results. The average initial low dose (33 patients) was 4.8 ± 0.8 mg and the average initial high dose (40 patients) was 9.0 ± 1.2 mg. The mean time to first INR of 2.0 or greater was similar, 3.4 and 3.0 days, respectively (p=0.38). The low‐dose group had fewer bleeds (7 vs 13, p=0.28) and doses held (11 vs 18 patients, p=0.27, 30 vs 50 doses). Four patients in each group received vitamin K (p=0.8). Forty‐four percent of patients with an INR of 4 or above and 48% of patients who had a dose held were on a long‐term drug or had a new drug added that could cause a major drug interaction with warfarin.

Conclusion. In this pilot study, hospitalized elderly who received a low versus high initial dose of warfarin achieved therapeutic INRs in a similar time and had lower but not significantly different safety outcomes.
Cost‐Effectiveness of Sevelamer versus Calcium Carbonate plus Atorvastatin to Reduce LDL in Patients with Chronic Renal Insufficiency with Dyslipidemia and Hyperphosphatemia
Authors: Brophy Donald F. , Wallace Joel F. , Kennedy Daniel T. , Gehr Todd W. B. , Holdford David A.
Published: June 2004

We conducted a cost‐effectiveness analysis to compare costs and clinical outcomes of sevelamer versus calcium carbonate plus atorvastatin for treatment of dyslipidemia in patients with chronic renal insufficiency. The model was from the third‐party payer perspective. Efficacy and adverse event rates for each regimen were obtained from published clinical trials. Drug costs were based on average wholesale prices; monitoring costs were based on Medicare reimbursement rates. Our model suggests that the combination of calcium carbonate plus atorvastatin is substantially more cost‐effective than sevelamer in reducing low‐density lipoprotein (LDL) in these patients. Oneway sensitivity analyses were performed to assess if 25% and 50% price reductions in sevelamer affected overall cost‐effectiveness results. A 50% sevelamer price reduction was less expensive than combination therapy but remained less cost‐effective. A two‐way sensitivity analysis on the probability that a patient achieves the goal of a 35% LDL reduction resulted in calcium carbonate plus atorvastatin remaining more cost‐effective. Further cost‐effectiveness studies are necessary to corroborate our data.
Treatment of Epilepsy in the New Millennium
Authors: Pellock John M.
Published: June 2004

Treatment options for epilepsy have increased markedly since 1990, when only carbamazepine, phenytoin, phenobarbital, primidone, and valproate were used commonly for partial and secondarily generalized seizures. Those with primary generalized seizures received ethosuximide or valproate. Over the past decade, however, additional agents have been introduced, with the promise of improved seizure control and minimal side effects. The new antiepileptic drugs (AEDs)—felbamate, gabapentin, lamotrigine, tiagabine, topiramate, vigabatrin and oxcarbazepine—have demonstrated superior efficacy for some with refractory epilepsy. In addition, the new agents frequently are better tolerated when used as monotherapy or adjunctive therapy. The optimal place for the new AED will require additional studies and careful postmarketing surveillance and assessments. Although these AEDs offer benefits, not all patients with epilepsy have responded. Thus, the search for new AEDs continues.
Antiepileptic Drug Pharmacokinetics and Interactions: Impact on Treatment of Epilepsy
Authors: Cloyd James C. , Remmel Rory P.
Published: June 2004

An understanding of epilepsy therapy's pharmacokinetic and drug interaction principles—combined with knowledge of antiepileptic drug (AED) clinical pharmacology—allows more effective use of these drugs. The most desirable pharmacokinetic characteristic is a linear relationship between dose and steady‐state concentration, as this determines the ease or difficulty in determining the appropriate dose. Drug‐drug interactions affecting AED metabolism are common, clinically important, and, until recently, often unpredictable. Advances in molecular biology have identified specific enzymes responsible for AED metabolism and interactions. Clinicians now can identify potential interactions and avoid or manage them by adjusting drug dosage. Most newer AEDs follow or approximate linear pharmaco‐kinetics, are absorbed extensively and consistently, are not significantly bound to plasma proteins, do not form active metabolites, and have few, if any, drug interactions. In cases where interactions occur between newer AEDs and other drugs, knowledge of these interactions reduces the likelihood of serious adverse events. The pharmacokinetics of the newer AEDs simplify drug dosing and monitoring and should lead to improved patient care.
Antiepileptic Drug Treatment: Outcomes and Adherence
Authors: Garnett William R.
Published: June 2004

The goal in treating patients with epilepsy is a cost‐effective approach to the elimination of seizures or a reduction in their number and frequency while avoiding drug interactions and side effects, so as to achieve the best possible quality of life. Among the desirable outcomes are an enhanced understanding of epilepsy by patients, caregivers, and society, and a lessening of the psychosocial risks of this disease. Patients fail to achieve their goals and outcomes when they fail to adhere to the drug regimen or when a less‐than‐adequate drug regimen is prescribed. To help improve adherence, once‐ or twice‐daily formulations should be used. New antiepileptic drugs (AEDs) increase the possibility of effective treatment for a patient who initially fails therapy. Working together, patients and clinicians can maximize the effectiveness of AED therapy and the potential for achieving desired goals and outcomes.
A robust air‐gap flux estimation for speed sensorless vector control of double‐star induction machine
Authors: Mimouni M.F. , Dhifaoui R.
Published: June 2004

The paper presents a new direct field‐oriented control (DFOC) for double‐star induction machine (DSIM) drives using the stator currents. First, we propose a new algorithm to estimate air‐gap flux for speed sensorless air‐gap flux orientation control. Compared to the previous DFOC schemes the new one is independent from any motor parameter variation, specially on the stator resistance. Then, the DFOC is associated with a low pass filter (LPF) to solve the dc drift problems caused by the pure integration of air‐gap flux. In the present paper, the rotor resistance is estimated by an algorithm using Lyapunov theory. Good results have been obtained in the benchmark simulations. Copyright © 2004 John Wiley & Sons, Ltd.
Towards a Transparent, Highly Conductive Poly(3,4‐ethylenedioxythiophene)
Authors: Ha Y.‐H. , Nikolov N. , Pollack S. K. , Mastrangelo J. , Martin B. D. , Shashidhar R.
Published: June 2004

A detailed investigation of the processing parameters influencing the oxidative polymerization of 3,4‐ethylenedioxythiophene (EDOT) and a methanol‐substituted derivative (EDOT–CH2OH) was performed with the goal of maximizing the conductivity of the polymer. We show that the conductivity can be significantly enhanced by varying the monomer, oxidant (iron(III) p‐toluenesulfonate (Fe(OTs)3)), weak base (imidazole (Im)), solvent (various alcohols), and solution concentrations. The effect of each variable on the final materials properties is investigated, and the parameters have been optimized to achieve conductivities as high as 900 S cm–1. Surface resistance below 150 Ω/□ for 80–90 nm thick films with visible‐spectrum transparency exceeding 80 % is achieved. The combination of these properties makes the films highly suitable for numerous device applications.
Electric‐Field‐Directed Growth of Gold Nanorods in Aqueous Surfactant Solutions
Authors: Pérez‐Juste J. , Liz‐Marzán L. M. , Carnie S. , Chan D. Y. C. , Mulvaney P.
Published: June 2004

The factors affecting the nucleation and growth of gold nanorods, (Jana et al., Adv. Mater. 2001, 13, 1389) have been investigated. It is shown that the size and aspect ratio can be controlled through the use of different sized seed particles. The length of the rods can be tuned from 25–170 nm, while the width remains almost constant at 22–25 nm. The formation of rods requires the presence of the cationic surfactant cetyltrimethylammonium bromide (CTAB). Lower temperature favors rod formation, although this reduces CTAB solubility. The addition of chloride ions or the use of dodecyltrimethylammonium bromide (DTAB) leads to shorter‐aspect rods. AuIII and AuI are shown to be quantitatively bound to the CTAB micelles. We propose an electrochemical mechanism for rod formation, whereby the flux of AuI bound to cationic micelles to the seed surface is maximized at points of highest curvature, where the electrical double layer gradient is highest. Initial numerical solutions to the electric potential and field around an ellipsoid in a 1:1 electrolyte are provided, which indicate that the field at the particle tip scales linearly with the aspect ratio. Mean free passage times for ions are found to be shortest at the tips. The results provide a general explanation for the formation of non‐equilibrium crystal habits and a mechanism for controlling crystal growth.
Surface Molecularly Imprinted Polymer Core–Shell Particles
Authors: Carter S. R. , Rimmer S.
Published: June 2004

Core–shell molecularly imprinted polymers (CS‐MIPs) have been prepared by aqueous emulsion polymerization using water‐soluble template molecules. An amphiphilic binding monomer, oleyl phenyl hydrogen phosphate and ethylene glycol dimethacrylate were used in the formation of highly crosslinked surfaces around divinyl benzene crosslinked polystyrene core colloids. Evidence was obtained by transmission electron microscopy (TEM) for a change in surface morphology when the polymer shell was formed in the presence of a template. The caffeine‐imprinted polymers were shown to bind caffeine in preference to theophylline from an equimolar mixture of the compounds in aqueous solution at pH 7.0, whilst concentration–binding (Scatchard) curves revealed the presence of two populations of binding sites in aqueous phosphate buffer at pH 8.0 for caffeine and theophylline. Similar studies were also carried out for (S)‐propranolol and (S)‐atenolol at pH 5.5, which also revealed the presence of two populations of binding sites for core–shell particles imprinted with these compounds. (S)‐Propranolol was selectively removed from a solution of (S)‐propranolol and (S)‐atenolol by both of the CS‐MIPs, whereas the non‐imprinted particle showed no selectivity for either component.
Well‐Aligned ZnO Nanowire Arrays Fabricated on Silicon Substrates
Authors: Geng C. , Jiang Y. , Yao Y. , Meng X. , Zapien J. A. , Lee C. S. , Lifshitz Y. , Lee S. T.
Published: June 2004

Arrays of well‐aligned single‐crystal zinc oxide (ZnO) nanowires of uniform diameter and length have been synthesized on a (100) silicon substrate via a simple horizontal double‐tube system using chemical vapor transport and condensation method. X‐ray diffraction and transmission electron microscopy (TEM) characterizations showed that the as‐grown nanowires had the single‐crystal hexagonal wurtzite structure with detectable defects and a <0002> growth direction. Raman spectra revealed phonon confinement effect when compared with those of ZnO bulk powder, nanoribbons, and nanoparticles. Photoluminescence exhibited strong ultraviolet emission at 3.29 eV under 355 nm excitation and green emission at 2.21 eV under 514.5 nm excitation. No catalyst particles were found at the tip of the nanowires, suggesting that the growth mechanism followed a self‐catalyzed and saturated vapor–liquid–solid (VLS) model. Self‐alignment of nanowires was attributed to the local balance and steady state of vapor flow at the substrate. The growth technique would be of particular interest for direct integration in the current silicon‐technology‐based optoelectronic devices.
Synthesis and Characterization of Electrochromic Polyamides with Well‐Defined Molecular Structures and Redox Properties
Authors: Gao J. , Liu D.‐G. , Sansiñena J.‐M. , Wang H.‐L.
Published: June 2004

In this paper we report the synthesis and characterization of a series of electrochromic polyamides (alternating copolymers). The synthesis proceeds via the condensation polymerization between amine‐capped oligoaniline and acyl chlorides such as isophthaloyl dichloride, terephthaloyl chloride, azelaoyl chloride, and dodecanedioyl dichloride. Both the orthogonal tert‐butoxycarbonyl (BOC) group on the oligoaniline segment and the non‐conjugated aromatic or aliphatic segment on the polymer backbone play a vital role in the formation of the final polyamides with good solubility in common organic solvents. We cast thin polyamide films from their chloroform solutions and studied their electrochemical behavior and spectroscopic properties. In contrast to the polyaniline, the copolymers bearing oligoaniline segments show four distinct oxidation states, which were fully characterized using IR and UV‐vis spectroscopy. The copolymer thin films also exhibit electrochromic behavior when a linear potential sweep is applied. Compared with the polyaniline, the polyamides adhere much more strongly to the indium tin oxide (ITO) coated glass and show no signs of delamination after hundreds of redox cycles in a hydrochloric acid solution. We believe that these factors make these novel polyamides very attractive as electrochromic materials.
The First Template‐Free Growth of Crystalline Silicon Microtubes
Authors: Hu J. , Bando Y. , Liu Z. , Zhan J. , Golberg D.
Published: June 2004

A simple template‐free high‐temperature evaporation method was developed for the growth of crystalline Si microtubes for the first time. As‐grown Si microtubes were characterized using X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, and room‐temperature photoluminescence. The lengths of the Si tubes can reach several hundreds of micrometers; some of them have lengths on the order of millimeters. Each tube has a uniform outer diameter along its entire length, and the typical outer diameter is ≈ 2–3 μm. Most of the tubes have a wall thickness of ≈ 400–500 nm, though a considerable number of them exhibit a very thin wall thickness of ≈ 50 nm. Room‐temperature photoluminescence measurement shows the as‐synthesized Si microtubes have two strong emission peaks centered at ≈ 589 nm and ≈ 617 nm and a weak emission peak centered at ≈ 455 nm. A possible mechanism for the formation of these Si tubes is proposed. We believe that the present discovery of the crystalline Si microtubes will promote further experimental studies on their physical properties and smart applications.
Porphyrin‐ and Fullerene‐Based Molecular Photovoltaic Devices
Authors: Imahori H. , Fukuzumi S.
Published: June 2004

We have developed a novel strategy for the construction of molecular photovoltaic devices where the porphyrins and fullerenes employed as building blocks are organized into nanostructured artificial photosynthetic systems by self‐assembly processes. Highly efficient photosynthetic energy‐ and electron‐transfer processes take place at gold and indium tin oxide (ITO) electrodes modified with self‐assembled monolayers of porphyrin‐ or fullerene linked systems. Porphyrins and fullerenes have also been assembled step by step to make large and uniform clusters on nanostructured semiconductor electrodes, which exhibit a high power‐conversion efficiency of close to 1 %. These results will provide valuable information on the design of donor–acceptor‐type molecular assemblies that can be tailored to construct highly efficient photovoltaic devices.
Organic Thin‐Film Transistors Based on Tolyl‐Substituted Oligothiophenes
Authors: Mohapatra S. , Holmes B. T. , Newman C. R. , Prendergast C. F. , Frisbie C. D. , Ward M. D.
Published: June 2004

Thin films based on the tolyl‐substituted oligothiophenes 5,5′′‐bis(4‐methylphenyl)‐2,2′:5′,2′′‐terthiophene (1), 5,5′′′‐bis(4‐methylphenyl)‐2,2′:5′,2′′:5′′,2′′′‐quaterthiophene (2) and 5,5′′′′‐bis(4‐methylphenyl)‐2,2′:5′,2′′:5′′,2′′′:5′′′,2′′′′‐quinqethiophene (3) exhibit hole‐transport behavior in a thin‐film transistor (TFT) configuration, with reasonable mobilities and high current on/off (Ion/Ioff) ratios. Powder X‐ray diffraction (PXRD) reveals that these films, grown by vacuum deposition onto the thermally grown silicon oxide surface of a TFT, are highly crystalline, a characteristic that can be attributed to the general tendency of phenyl groups to promote crystallinity. Atomic force microscopy (AFM) reveals that the films grow layer by layer to form large domains, with some basal domain areas approaching 1000 μm2. The PXRD and AFM data are consistent with an “end‐on” orientation of the molecules on the oxide substrate. Variable‐temperature current–voltage (I–V) measurements identified the activation regime for hole transport and revealed shallow level traps in thin films of 1 and 2, and both shallow and deep level traps in thin films of 3. The activation energies for thin films of 1, 2, and 3 were similar, with values of Ea = 121, 100, and 109 meV, respectively. The corresponding trap densities were Ntrap/Nv = 0.012, 0.023, and 0.094, where Ntrap is the number of trap states and Nv is the number of conduction states. The hole mobilities for the three compounds were similar (μ ≃ 0.03 cm2 V–1 s–1), and the Ion/Ioff ratios were comparable with the highest values reported for organic TFTs, with films of 2 approaching Ion/Ioff = 109 at room temperature.
Self‐Assembling Polymer–Peptide Conjugates: Nanostructural Tailoring
Authors: Collier J. H. , Messersmith P. B.
Published: June 2004

The synthesis and solution behavior of a series of β‐sheet fibril‐forming peptide–polymers is described. Several block copolymer architectures are explored, with various lengths and arrangements of the peptide and polymer blocks. One peptide–polymer, an 11‐amino acid peptide conjugated to a polydisperse poly(ethylene glycol) chain, has the ability to form uncommonly regular, aligned, and minimally aggregated β‐sheet fibrils (see Figure).
Organometallic Block Copolymers as Catalyst Precursors for Templated Carbon Nanotube Growth
Authors: Hinderling C. , Keles Y. , Stöckli T. , Knapp H. F. , de los Arcos T. , Oelhafen P. , Korczagin I. , Hempenius M. A. , Vancso G. J. , Pugin R. , Heinzelmann H.
Published: June 2004

The use of organic–organometallic block copolymers as catalyst precursors for templated carbon nanotube (CNT) growth (see Figure) is demonstrated for the first time. A thin film of block copolymer was treated with O2 plasma to produce ordered iron‐containing catalyst nanoparticle arrays, which are efficient catalysts for CNT growth. This approach allows control of catalyst domain size and spacing by tailoring block copolymer composition.
PbS Quantum Dots with Stable Efficient Luminescence in the Near‐IR Spectral Range
Authors: Bakueva L. , Gorelikov I. , Musikhin S. , Zhao X. S. , Sargent E. H. , Kumacheva E.
Published: June 2004

The most desirable features of PbS nanocrystal (NC) synthesis are demonstrated in a new one‐stage route: Aqueous synthesis to enable compatibility with biological assays and polymer–nanocrystal device fabrication; simplicity; non‐toxic solvents; and moderate reaction temperatures. The NCs produced (see Figure) have stable, narrow fluorescence peaks that are size‐tunable in the near‐IR spectral range and a high quantum yield.
Layered MnO2 Nanobelts: Hydrothermal Synthesis and Electrochemical Measurements
Authors: Ma R. , Bando Y. , Zhang L. , Sasaki T.
Published: June 2004

A cathode material for rechargeable lithium batteries is one possible application for the birnessite‐related layered MnO2 nanobelts (see Figure) reported here. A simple hydrothermal procedure is described that results in high‐purity, long (up to several tens of micrometers) nanobelts with narrow size dispersion (width 5–15 nm) that are usually self‐assembled into bundles.
A Photoinduced Spin Transition Iron(II) Complex with Liquid‐Crystal Properties
Authors: Hayami S. , Danjobara K. , Inoue K. , Ogawa Y. , Matsumoto N. , Maeda Y.
Published: June 2004

The iron(II) complex [Fe(3C16‐L)2(NCS)2] (see Figure) exhibits three coexisting physical properties due to its geometric flexibility. It shows liquid‐crystal behavior in the temperature range 345–400 K, spin‐crossover behavior (T1/2 = 217 K) between high‐spin and low‐spin states, and photoinduced spin transition (T(LIESST; light‐induced excited spin state trapping) = 61 K) from a low‐spin state to a metastable high‐spin state.
Mitochondrial DNA and Alu insertions in a genetically peculiar population: The Ayoreo Indians of Bolivia and Paraguay
Authors: Dornelles C.L. , Battilana J. , Fagundes N.J.R. , Freitas L.B. , Bonatto S.L. , Salzano F.M.
Published: June 2004

A total of 91 Ayoreo individuals previously studied for blood groups and protein markers, living in two Bolivian and one Paraguayan communities, were extensively investigated in relation to the hypervariable 1 segment of the control and eight coding regions of their mitochondrial DNA (mtDNA). They show an extremely reduced mtDNA variability, the observed haplotypes being classifiable in just two haplogroups (C and D). They were also variously studied in relation to six Alu insertions; in this case, however, the prevalences found did not depart markedly from those obtained in other populations of this ethnic group. To assess the Ayoreo position in relation to these populations, 11 other groups that had also been studied for these systems and for blood groups and proteins were selected. The dendrograms obtained with two of the three sets of markers showed distinct patterns, but the Ayoreo were placed in a central position in both the blood group + proteins and Alu insertions trees. Therefore, they are clearly distinct in relation to their mtDNA only, suggesting a strong founder effect and/or random loss of variability in this system. Am. J. Hum. Biol. 16:479–488, 2004.© 2004 Wiley‐Liss, Inc.
Growth of Han migrants at high altitude in central Asia
Authors: Weitz Charles A. , Garruto Ralph M.
Published: June 2004

Han Chinese of low‐altitude descent have been living in Qinghai Province of Western China for at least two millennia. For most of this time they have lived at elevations under 2,500 m. However, during the last four decades an increasing number of Han have moved into high‐altitude towns at elevations over 3,000 m, and some above 4,000 m. There are now sufficient numbers of Han descendants who have been born and raised at high altitude to allow a comparison of their morphological and physiological growth patterns with low‐altitude Han to detect the effect of hypoxia. The field study reported here was conducted by collaborating Chinese and American researchers over a 6‐year period, and included 1,227 Han living at high altitude in Qinghai and at low altitude near Beijing. This study demonstrates that Han born and raised at high altitude are smaller and lighter than those at low altitude—particularly as children and adolescents. Slower growth at high altitude may be a consequence of hypoxia, but it also corresponds to poorer economic conditions in rural Qinghai Province, and thus may reflect nutritional inadequacies. Differences in altitude and/or nutrition do not seem to affect thorax dimensions, since, relative to stature, chest dimensions are similar at both high and low altitudes. Nevertheless, lung volumes are higher among Han at high altitude, possibly reflecting the influence of hypoxia on alveolar growth. The hematological values of Han growing up at 3,200 m are not different from those at low altitude—an unusual finding relative to other low‐altitude groups that may reflect population differences in response to hypoxia. At 3,800 m and 4,300 m, however, Han show elevated hemoglobin relative to Han at low altitude. Am. J. Hum. Biol. 16:405–419, 2004. Published 2004 Wiley‐Liss, Inc.
Kin‐structured migration: Causes and consequences
Authors: Fix Alan G.
Published: June 2004

Migration among local populations classically has been seen as the principal process retarding genetic microdifferentiation. However, as Sewall Wright pointed out long ago, migration may also act as a random differentiating force. In fact, when migrants comprise a biological kin group, migration may be considered a component of genetic drift. The causes of kin‐structured migration (KSM) lie in the common, if not universal, tendency for kin to associate and cooperate. However, similar to genetic drift, KSM has its greatest effect in smaller populations and is most apparent in low‐density fission–fusion societies such as the Yanomamo of South America and the Semai of Malaysia, and less salient in higher density, low‐mobility populations such as those of the New Guinea Highlands. The evolutionary consequences of KSM begin with increased genetic variation among populations. Such intergroup variation provides a basis for group selection. The origin of larger‐scale geographic differentiation can arise from kin‐structured migrant groups colonizing new regions. Waves of colonizing kin‐structured founder groups may produce gene frequency clines, mimicking demic diffusion and natural selection. Finally, because kin structuring reduces the effective size of a population, it may be speculated that the extremely small effective size inferred for ancestral populations of Homo sapiens may be an artifact of kin‐structured demographically larger populations. Am. J. Hum. Biol. 16:387–394, 2004. © 2004 Wiley‐Liss, Inc.
Phenotype characterization and natural history of spondylothoracic dysplasia syndrome: A series of 27 new cases
Authors: Cornier A.S. , Ramírez N. , Arroyo S. , Acevedo J. , García L. , Carlo S. , Korf B.
Published: June 2004

Spondylothoracic dysplasia (STD, MIM#277300) is an autosomal recessive disorder with high prevalence in the Puerto Rican population. It is generally regarded as a lethal condition. Since Jarcho and Levin described it in 1938, it has been referred to as spondylocostal dysplasia, costovertebral dysplasia, Jarcho–Levin syndrome and STD. We have prospectively characterized 27 patients with STD by detailed physical examination, pedigree analysis, thoracic CT scans, and pulmonary function tests (PFTs). Diagnoses were established using spinal radiographs and 3‐D reconstructive CT scans to demonstrate fusion of the ribs at the costo‐vertebral junction with a fan‐like (crab‐like) configuration of the thorax. Vertebral segmentation and formation defects were seen throughout the spine with a decrease in the number of vertebral bodies. Characteristic vertebral shape consisted of a decrease in antero‐posterior diameter and an increase in lateral length, giving the vertebra a sickle shape. Eight out of 18 prospectively follow patients died within the first 6 months of life, a 44% mortality rate. Cause of death was respiratory insufficiency secondary to pneumonia and pulmonary restriction. This is an important finding since the vast majority of STD syndrome patients cited in the medical literature have died in the newborn and early childhood periods. Age of the remaining patients ranged from 4 months to 47 years. This represents the largest collection of patients with STD reported and it has allowed us to determine a detailed phenotype. Given 56% survival at 6 months, we show that STD is not a lethal syndrome. © 2004 Wiley‐Liss, Inc.
Familial symptom domains in monozygotic siblings with autism
Authors: Kolevzon Alexander , Smith Christopher J. , Schmeidler James , Buxbaum Joseph D. , Silverman Jeremy M.
Published: June 2004

Autism is characterized by a triad of symptom domains (impaired social interaction, communication deficits, and repetitive behaviors) that vary significantly in their clinical presentation across the population. Within families with more than one affected member, however, discrepant findings exist with regard to symptom variability. Reduced intrafamily variance is of particular importance because it supports an underlying model of genetic heterogeneity in the transmission of autism, and the identification of familial clinical subtypes can be used to select more homogeneous samples for linkage analysis in the future. This study examines whether there are specific features of autism that show decreased variance within 16 families with monozygotic siblings concordant for autism. Evidence for familiality was defined as significantly decreased variance of symptom levels within monozygotic siblingships as compared to between siblingships. Using regression analysis, we demonstrated significant aggregation of symptoms within monozygotic siblingships for two of the three main symptom domains in autism: impairments in communication and social interaction showed significant familiality. Within the repetitive behavior domain, only the categories of circumscribed interests and preoccupation with part‐objects showed reduced variance within siblingships. In addition, with the exception of a negative association between the social and behavior domains, partial correlation coefficients did not reveal significant associations between the levels of different symptom domains within families, suggesting that the levels of clinical features seen in autism may be a result of mainly independent genetic traits. Because of presumed genetic heterogeneity and the wide clinical variation seen in autism and other pervasive developmental disorders, selecting probands according to specific features known to show reduced variance within families may provide more homogeneous samples for genetic analysis and strengthen the power to detect the specific genes involved in autism. © 2004 Wiley‐Liss, Inc.
Nickel‐katalysierte reduktive Cyclisierungen und Kupplungen
Authors: Montgomery John
Published: June 2004

Seit mehr als 50 Jahren wird Nickel als Katalysator in Cycloadditionen eingesetzt. Nickel‐katalysierte reduktive Kupplungen und Cyclisierungen sind hingegen erst in letzter Zeit intensiver untersucht worden, wobei inzwischen Mehrkomponenten‐Kupplungen von zwei oder mehr π‐Komponenten mit einem Hauptgruppen‐ oder Übergangsmetallreagens möglich sind. Mit diesen Methoden sind aus leicht verfügbaren Ausgangsmaterialien wichtige organische Strukturelemente zugänglich, unter anderem sind Verbindungen mit mehreren benachbarten Stereozentren, polycyclische Ringsysteme und Reaktionsprodukte mit komplexer Funktionalität aus einfachen, achiralen, acyclischen Vorstufen synthetisiert worden. Angesichts der Beteiligung von drei oder mehr reaktiven funktionellen Gruppen an der Katalyse sind zum Reaktionsmechanismus noch zahlreiche Fragen offen, etwa zur zeitlichen Abfolge der Bindungsbildungen und zur Natur reaktiver Intermediate. In diesem Aufsatz geben wir einen Überblick über neuere Fortschritte auf diesem sich schnell entwickelnden Gebiet.
Nickel‐Catalyzed Reductive Cyclizations and Couplings
Authors: Montgomery John
Published: June 2004

For over 50 years, nickel catalysis has been applied in cycloaddition processes. Nickel‐catalyzed reductive couplings and cyclizations, however, have only recently attracted a high level of interest. This group of new reactions allows a broad range of multicomponent couplings involving two or more π components with a main‐group or transition‐metal reagent. These processes allow the assembly of important organic substructures from widely available reaction components. Multiple contiguous stereocenters, polycyclic ring systems, and novel arrays of complex functionality may often be prepared from simple, achiral, acyclic precursors. With three or more reactive functional groups participating in the catalytic processes, many mechanistic questions abound, including the precise timing of bond constructions and the nature of reactive intermediates. This Review is thus aimed at providing a critical evaluation of recent progress in this rapidly developing field.
Parametermodell zur Bestimmung des direkten Anteils des Tageslichtquotienten in Räumen mit Oberlichtern
Authors: von Grabe Jörg
Published: June 2004

Im folgenden Beitrag wird ein Parametermodell für die Berechnung des direkten Anteils des Tageslichtquotienten in Räumen mit diffus transmittierenden Fensterflächen (Strahlflächen) polygonaler Form dargestellt. Mit Hilfe dieses Modells lassen sich die unten beschriebenen Parameter anhand der Anforderungen an die Höhe und an die Gleichmäßigkeit der Beleuchtungsstärke im Innenraum optimieren, ohne auf aufwendige Raytracing‐Modelle zurückgreifen zu müssen. Als Grundlage der Berechnungsgleichung werden zunächst die erforderlichen Grundgrößen der Lichttechnik erläutert. Anschließend wird auf der Basis des photometrischen Entfernungsgesetzes eine Gleichung entwickelt, die das Verhältnis der Beleuchtungsstärke auf der Außenseite der Strahlfläche zur Beleuchtungsstärke auf der Empfängerfläche beschreibt. Für den Spezialfall der rechteckigen Strahlfläche wird dabei die Neigung der strahlenden Fläche durch die Drehung des Koordinatensystems in einer der Hauptachsen und die entsprechende Anpassung der Integrationsgrenzen berücksichtigt. Aus den entwickelten Gleichungen kann abschließend das Verhältnis zwischen der äußeren horizontalen Beleuchtungsstärke und der Beleuchtungsstärke auf der geneigten Fläche abgeleitet und somit der direkte Anteil des Tageslichtquotienten bestimmt werden.
Untersuchungen zum thermisch induzierten Luftwechselpotential von Kippfenstern
Authors: Hall Monika
Published: June 2004

Die sogenannte natürliche Lüftung — Lüftung infolge Temperatur‐ und Windeinwirkung über geöffnete Türen und Fenster — ist auch heute noch in Wohngebäuden die verbreitetste Form des Lüftens. Da die Lüftung über Kippfenster eine übliche Form des Lüftens ist, ist die Kenntnis des Luftwechsels über Kippfenster von großem Interesse. Der Vergleich von Ansätzen aus der Literatur zur Berechnung des Luftwechsels über Kippfenster zeigt, daß diese unter Verwendung gleicher Randbedingungen zu unterschiedlichen Ergebnissen führen. Aus diesem Grund wird aus eigenen Messungen ein Modellansatz abgeleitet, der die einseitige, thermisch induzierte Kippfensterlüftung besser beschreibt und gleichzeitig das Vorhandensein einer Laibung und/oder einer Heizung berücksichtigt.
5000 Jahre Biotechnologie: Vom Wein zum Penicillin
Authors: Ulber Roland , Soyez Konrad
Published: June 2004

Die Biotechnologie begleitet den Menschen seit Jahrtausenden. Sie war lange eher unbeachtet empirisch immer weiter entwickelt worden und hat so stetig zur gesellschaftlichen Entwicklung des Menschen beigetragen. In Zeiten materieller Engpässe wurden in rasantem Tempo biotechnologische Prozesse entwickelt. Beispiele sind die Verfahren zur Herstellung von Aceton, Glycerin oder Butanol während des Ersten Weltkrieges und die Entwicklung der Antibiotika während des Zweiten Weltkrieges.