bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical efficacy and safety of dexmedetomidine used as a preanesthetic prior to general anesthesia in cats
Authors: McSweeney Patrick M. , Martin David D. , Ramsey Deborah S. , McKusick Brett C.
Published: February 2012

Objective—To evaluate the clinical efficacy of dexmedetomidine as a preanesthetic medication administered prior to anesthetic induction with ketamine or propofol and with or without isoflurane for maintenance of anesthesia.

Design—Randomized, blinded, controlled clinical trial.

Animals—184 client-owned cats.

Procedures—Cats requiring general anesthesia for short or long procedures were assigned to receive 1 of 4 preanesthetic and induction drug combinations (dexmedetomidine and ketamine, placebo [saline {0.9% NaCl} solution] and ketamine, dexmedetomidine and propofol, or placebo and propofol). Cats undergoing long procedures received isoflurane for maintenance of anesthesia.

Results—Administration of dexmedetomidine prior to anesthetic induction with ketamine significantly increased the intubation success rate (57/64 [89%]), compared with the success rate for the placebo (4/37 [11 %]); significantly reduced the median induction dose of propofol (≤ 5.1 mg/kg [2.32 mg/lb]), compared with that for the placebo (≤ 10.5 mg/kg [4.77 mg/lb]); and significantly reduced the isoflurane concentration (1.5%) required for anesthesia maintenance, compared with that for the placebo (3.0%). Postoperatively, fewer cats receiving dexmedetomidine required rescue analgesia, and cats had lower pain scores for at least 2 hours after surgery, compared with results for cats receiving the placebo. Heart rate was lower during the procedure and respiratory rate and rectal temperature were lower during and after the procedure for cats receiving dexmedetomidine. More cats that received dexmedetomidine had emesis and pale mucous membranes, compared with the number of cats with those signs that received placebo.

Conclusions and Clinical Relevance—Dexmedetomidine as a preanesthetic was efficacious for clinical use in cats requiring general anesthesia.
Unusual perianesthetic malignant hyperthermia in a dog
Authors: Adami Chiara , Axiak Shannon , Raith Karina , Spadavecchia Claudia
Published: February 2012

Case Description—A 7-month-old male Siberian Husky affected by lower motor neuron tetraparesis was anesthetized for electrodiagnostic testing and collection of muscle and nerve biopsy specimens.

Clinical Findings—Preanesthetic physical examination revealed a high rectal temperature, and serum biochemical analysis revealed high muscle and liver enzyme activities. The dog was anesthetized twice. The dog was anesthetized with isoflurane and developed moderate hypercarbia and mild hyperthermia. Injectable anesthetic agents were used to anesthetize the dog the second time, during which the dog developed severe malignant hyperthermia. A genetic test performed after anesthesia did not reveal a mutation of the RYR1 gene, the gene that mediates calcium-release channels in skeletal muscle. On the basis of clinical features, and because other neuromuscular disorders were ruled out, a genetic channelopathy involving the skeletal muscle ion channels was suspected.

Treatment and Outcome—The dog was disconnected from the breathing system, and active cooling of the body was performed with ice packs applied to the body surface and alcohol applied to the foot pads. Cold crystalloid solutions were administered IV. Intermittent positive-pressure ventilation with 100% oxygen was performed to decrease end-tidal partial pressure of carbon dioxide. Because dantrolene was not available, acepromazine was administered to facilitate a decrease in body temperature. The dog recovered from malignant hyperthermia and was discharged to the owner after 13 days of hospitalization.

Clinical Relevance—Dogs affected by genetic muscle disorders should be considered at risk for perianesthetic malignant hyperthermia, even in the absence of an RYR1 gene mutation.
Synthesis and Molecular Structure of tert-Butyl 4-(2-tert-butoxy-2-oxoethyl)piperazine-1-carboxylate
Authors: Mamat Constantin , Flemming Anke , Köckerling Martin
Published: February 2012

The crystal and molecular structure of tert-butyl 4-(2-tert-butoxy-2-oxoethyl)-piperazine-1-carboxylate is reported. The title compound crystallizes from a petroleum ether/ethyl acetate mixture in the monoclinic space group P 21/c with four molecules in the unit cell. The unit cell parameters are: a = 8.4007(2) Å, b = 16.4716(4) Å, c = 12.4876(3) Å; β = 90.948(1)° and V = 1727.71(7) Å3. Bond lengths and angles of this piperazine-carboxylate are typical.
Influence of n-Hexane on in Situ Transesterification of Marine Macroalgae
Authors: Sánchez Angel , Maceiras Rocio , Cancela Angeles , Rodríguez Mónica
Published: February 2012

The purpose of this work is to investigate the influence of n-hexane addition on in situ transesterification of a solid raw material for biodiesel production. Extraction and reaction of macroalgae oil has been performed simultaneously in a batch reactor adding n-hexane with the reactants. In order to analyze the influence of n-hexane on the transesterification, the reaction was also carried out with sunflower oil. The results show that the presence of n-hexane does not have an important effect on the transesterification. It was also observed that this method requires large quantities of methanol to carry out the reaction. The best reaction conditions for in situ transesteriﬁcation of marine macroalgae were 300:1 methanol-to-oil molar ratio, 1% catalyst concentration, 60 °C reaction temperature and 11 h reaction time, resulting in a methyl esters yield of 17.1%. Thus, biodiesel production from macroalgae by transesterification in situ could be feasible, using hexane for the extraction and eliminating the previous extraction. This integrated method is thus effective and technically attractive.
Plants: An International Scientific Open Access Journal to Publish All Facets of Plants, Their Functions and Interactions with the Environment and Other Living Organisms
Authors: Fernando W.G. Dilantha
Published: February 2012

Plants are one of the two major groups of living organisms that are an essential entity to the function of the biosphere. Plants can be found in all known parts of the earth, in all shapes and sizes. They include the green algae, mosses, ferns, vines, grasses, bushes, herbs, flowering plants and trees. Although some plants are parasitic, most produce their own food through photosynthesis. Most plants initiate from a seed. The importance of plants in the food chain dates back to ancient times. The first humans gathered wild plants for food. As settlements developed, food crops were cultivated, leading to selection of high-yielding cultivated varieties to feed the growing populations. Unlike plants, humans and other animals are unable to manufacture their own food. Therefore, they are dependent, directly or indirectly, on plants. Plants are found in natural ecosystems such as rain forests, and also in agricultural areas and urbanized settings. They are an essential part of our daily lives providing food, clean air, and important ecosystem functions. The study of plants and their function could be considered the most complex of interactions. From the time a seed germinates, it goes through a myriad of physiological processes that can be closely studied using modern tools and molecular biological methods. An open access journal such as Plants will give millions of readers access to that information around the world.
Clinical Application of a New Plate Fixation System in Open-door Laminoplasty
Authors: Jiang Liangjun , Chen Weishan , Chen Qixin , Xu Kan , Wu Qionghua , Li Fangcai
Published: February 2012

The purpose of this retrospective clinical series was to evaluate the benefits and complications of plate fixation for open-door laminoplasty in cervical spondylotic myelopathy with multilevel spinal stenosis compared with open-door laminoplasty without fixation. Forty-nine patients underwent open-door laminoplasty for cervical myelopathy with multilevel spinal stenosis with at least 13 months of follow-up. A plate was used as the sole method of fixation between the lateral mass and lamina with 3 screws. Computed tomography scans obtained pre- and postoperatively were assessed for plate complications and spinal canal enlargement. Pre- and postoperative neurological condition was assessed by the Japanese Orthopedic Association (JOA) myelopathy score. Overall cervical spine range of motion (ROM) was measured in full flexion and extension radiographs pre- and postoperatively.

No restenosis due to door reclosure was noted, and no plates failed. No screws were backed out or broken. Almost all patients showed neurological improvement. The JOA score increased by 3.9±0.7 points in the suture group and 4.3±0.8 points in the plate group (
P
>.05). The postoperative increase in mean anteroposterior diameter of the spinal canal from C3 to C7 was 4.5±0.6 mm in the suture group and 5.1±0.5 mm in the plate group. The greater mean anteroposterior diameter increase in the plate group was statistically significant (
P
<.01). The mean cervical ROM decreased in the plate and suture groups postoperatively (
P
<.001). No significant difference was found in mean cervical ROM reduction between the groups (
P
>.05). No difference in axial symptoms was found between the 2 groups.
Free Vascularized Fibula Graft to Treat Chondroblastoma of the Hip
Authors: Riedel Barth , Franklin Corinna , Seal Alex , Stevanovic Milan
Published: February 2012

Chondroblastomas are rare tumors that present in the epiphysis of the long bones. Bone grafting following aggressive surgical curettage has yielded the best results. When present in the femoral head, they pose a higher risk of recurrence due to the difficulty of achieving an adequate resection without destroying the structural integrity of the weight-bearing surface.

This article describes a case of surgical treatment of a chondroblastoma of the femoral head with the use of a free vascularized fibula graft. A 26-year-old woman had several months of increasing left hip pain and decreased range of motion. Imaging studies confirmed a large bubbly lesion with sclerotic borders in the left femoral head consistent with chondroblastoma. After performing an aggressive and complete excisional biopsy, a large cavitary defect remained in the femoral head. Reconstruction of the defect and structural support was achieved using a free vascularized fibula. Nine years postoperatively, the patient had full hip motion, no pain, and no radiographic evidence of collapse. A free vascularized fibula graft is an excellent option for the reconstruction of a large femoral head defect after chondroblastoma resection.
Iatrogenic Subclavian Arteriovenous Fistula: Rare Complication of Plate Osteosynthesis of Clavicle Fracture
Authors: Ding Muliang , Hu Jianzhong , Ni Jiangdong , Lv Hongbin , Song Deye , Shu Chang
Published: February 2012

Iatrogenic subclavian arteriovenous fistula is rare and has not been reported as a complication of plate osteosynthesis of clavicle fracture. This article describes the first case of iatrogenic subclavian arteriovenous fistula caused by plate osteosynthesis.

A 36-year-old man sustained a right middle clavicle fracture in an injury and underwent open reduction and internal fixation with clavicular compression plate 3 days later in a local hospital. On the second postoperative day, a pulsatile mass and thrill were detected at the right supraclavicular region. The patient was discharged 3 days postoperatively with no extra inspection. Three months later, he was admitted to our institution because the mass was getting bigger and weakness was felt in his right upper limb. Digital subtraction angiography confirmed a subclavian arteriovenous fistula. Vascular surgeons treated the patient successfully using endovascular techniques. The subclavian arteriovenous fistula was eliminated with a fully expanded stent graft, and the plate was removed simultaneously. The result was satisfactory, and the postoperative course was uneventful.

This case demonstrated that subclavian arteriovenous fistula could be an iatrogenic complication of screw-and-plate osteosynthesis of clavicle fracture. The operative manipulation in the process of fracture reduction and hole drilling should be meticulous, and the screw length must be accurate. Orthopedic surgeons should be aware of this uncommon complication with plate osteosynthesis of clavicle fracture. We recommend using an endovascular surgical technique for treatment of this complication.
Persistent hiccups as the presenting symptom of a pulmonary embolism
Authors: Durning Steven , Shaw David J. , Oliva Anthony J. , Morris Michael J.
Published: February 2012

An 81-year-old male with a history of symptomatic bradycardia controlled by a pacemaker presented to our institution with three days of persistent hiccups. He denied any pulmonary symptoms and his initial evaluation showed no evidence of tachypnea, tachycardia, or hypoxia. Pacemaker malfunction or migration of the pacer leads was ruled out as an etiology and no intracranial pathology was present. Admission chest radiograph was normal but a computed tomography of the chest demonstrated a left lower lobe pulmonary embolus. After treatment with anticoagulation was initiated, the hiccups resolved within the next week. This is a unique case presentation of hiccups as the only presenting symptom of an otherwise asymptomatic pulmonary embolism.
Factors Associated with Resistance to Schistosoma mansoni Infection in an Endemic Area of Bahia, Brazil
Authors: Oliveira Ricardo R. , Figueiredo Joanemile P. , Cardoso Luciana S. , Jabar Rafael L. , Souza Robson P. , Wells Martin T. , Carvalho Edgar M. , Fitzgerald Daniel W. , Barnes Kathleen C. , Araújo Maria Ilma , Glesby Marshall J.
Published: February 2012

Detailed knowledge of factors associated with resistance to Schistosoma mansoni infection in endemic areas might facilitate more effective schistosomiasis control. We conducted a cross-sectional study of persons resistant to schistosomiasis and found no association between socioeconomic status and resistance to infection. Mononuclear cells of resistant subjects produced higher levels of interleukin-5 (IL-5), IL-13 and interferon-γ upon stimulation with soluble egg antigen (SEA) compared with infected persons. When stimulated with Sm21.6 or Sm22.6, levels of IL-10 were higher in cell culture of resistant persons. Levels of IgE against soluble adult worm antigen (SWAP) and against interleukin-4–inducing principle from S. mansoni eggs (IPSE) and levels of IgG4 against SWAP, SEA, and Sm22.6 were lower in the resistant group compared with the susceptible group. Our data suggest that socioeconomic status could not fully explain resistance to S. mansoni infection observed in the studied area. However, a mixture of Th1 and Th2 immune responses and low levels of specific IgG4 against parasite antigens could be mediating resistance to infection.
Infectious Etiologies of Acute Febrile Illness among Patients Seeking Health Care in South-Central Cambodia
Authors: Kasper Matthew R. , Blair Patrick J. , Touch Sok , Sokhal Buth , Yasuda Chadwick Y. , Williams Maya , Richards Allen L. , Burgess Timothy H. , Wierzba Thomas F. , Putnam Shannon D.
Published: February 2012

The agents of human febrile illness can vary by region and country suggesting that diagnosis, treatment, and control programs need to be based on a methodical evaluation of area-specific etiologies. From December 2006 to December 2009, 9,997 individuals presenting with acute febrile illness at nine health care clinics in south-central Cambodia were enrolled in a study to elucidate the etiologies. Upon enrollment, respiratory specimens, whole blood, and serum were collected. Testing was performed for viral, bacterial, and parasitic pathogens. Etiologies were identified in 38.0% of patients. Influenza was the most frequent pathogen, followed by dengue, malaria, and bacterial pathogens isolated from blood culture. In addition, 3.5% of enrolled patients were infected with more than one pathogen. Our data provide the first systematic assessment of the etiologies of acute febrile illness in south-central Cambodia. Data from syndromic-based surveillance studies can help guide public health responses in developing nations.
Detection and Transmission of Dientamoeba fragilis from Environmental and Household Samples
Authors: Stark Damien , Roberts Tamalee , Marriott Deborah , Harkness John , Ellis John T.
Published: February 2012

Dientamoeba fragilis is a commonly occurring pathogenic protozoan often detected at higher rates in stool samples than Giardia intestinalis. However, little is known about its life cycle and mode of transmission. A total of 210 environmental and household samples were examined for the presence of D. fragilis by culture and polymerase chain reaction. Of 100 environmental samples, D. fragilis was detected only in untreated sewage. In the household samples D. fragilis was detected in 30% of household contacts tested and was not detected in any domestic pets. This study provides evidence that environmental transmission of D. fragilis is unlikely and that pets played no role in transmission of the disease in this study. Direct transmission from infected persons is the most likely mode of transmission for D. fragilis. The study also highlights the need for household contacts to be screened, given the propensity of close contacts to become infected with the organism.
Recurrent Disseminated Intravascular Coagulation Caused by Intermittent Dosing of Rifampin
Authors: Havey Thomas C. , Cserti-Gazdewich Christine , Sholzberg Michelle , Keystone Jay S. , Gold Wayne L.
Published: February 2012

Daily rifampin therapy is associated with minimal adverse effects, but administration on an intermittent or interrupted basis has been associated with severe immunoallergic reactions such as hemolytic anemia, acute renal failure, and disseminated intravascular coagulation. We describe a patient with Mycobacterium leprae infection who experienced recurrent episodes of disseminated intravascular coagulation after intermittent exposures to rifampin, and review eight previously reported cases of rifampin-associated disseminated intravascular coagulation. In six (75%) cases, previous exposure to rifampin was reported and seven (87.5%) patients were receiving the medication on an intermittent or interrupted basis. Clinical features of rifampin-associated disseminated intravascular coagulation included fever, hypotension, abdominal pain, and vomiting within hours of ingestion. Average time to reaction was 3–6 doses if rifampin was being administered on a monthly schedule. Three (37.5%) of eight reported cases were fatal. A complete history of previous exposure to rifampin is recommended before intermittent therapy with this medication.
Impact of the isoprene photochemical cascade on tropical ozone
Authors: Paulot F. , Henze D. K. , Wennberg P. O.
Published: February 2012

Abstract. Tropical tropospheric ozone affects Earth's radiative forcing and the oxidative capacity of the atmosphere. Considerable work has been devoted to the study of the processes controlling its budget. Yet, large discrepancies between simulated and observed tropical tropospheric ozone remain. Here, we characterize some of the mechanisms by which the photochemistry of isoprene impacts the budget of tropical ozone. At the regional scale, we use forward sensitivity simulation to explore the sensitivity to the representation of isoprene nitrates. We find that isoprene nitrates can account for up to 70% of the local NOx = NO+NO2 sink. The resulting modulation of ozone can be well characterized by their net modulation of NOx. We use adjoint sensitivity simulations to demonstrate that the oxidation of isoprene can affect ozone outside of continental regions through the transport of NOx over near-shore regions (e.g., South Atlantic) and the oxidation of isoprene outside of the boundary layer far from its emissions regions. The latter mechanism is promoted by the simulated low boundary-layer oxidative conditions. In our simulation, ~20% of the isoprene is oxidized above the boundary layer in the tropics. Changes in the interplay between regional and global effect are discussed in light of the forecasted increase in anthropogenic emissions in tropical regions.
Late Removal of Titanium Hardware from the Elbow Is Problematic
Authors: Bachoura Abdo , Yoshida Ruriko , Lattermann Christian , Kamineni Srinath
Published: February 2012

A retrospective review of 21 patients that underwent bone screw removal from the elbow was studied in relation to the type of metal, duration of implantation, and the location of the screws about the elbow. Screw failure during extraction was the dependent variable. Five of 21 patients experienced hardware failure during extraction. Fourteen patients had titanium alloy implants. In four cases, titanium screws broke during extraction. Compared to stainless steel, titanium screw failure during removal was not statistically significant (P=0.61). Screw removal 12 months after surgery was more likely to result in broken, retained screws in general (P=0.046) and specifically for titanium alloy (P=0.003). Bone screws removed from the distal humerus or proximal ulna had an equal chance of fracturing (P=0.28). There appears to be a time-related association of titanium alloy bone screw failure during hardware removal cases from the elbow. This may be explained by titanium’s properties and osseointegration.
Morbidity and Quality of Life in Bladder Cancer Patients following Cystectomy and Urinary Diversion: A Single-Institution Comparison of Ileal Conduit versus Orthotopic Neobladder
Authors: Erber Barbara , Schrader Mark , Miller Kurt , Schostak Martin , Baumunk Daniel , Lingnau Anja , Schrader Andres Jan , Jentzmik Florian
Published: February 2012

Objective. To evaluate and compare noncontinent and continent urinary diversion after radical cystectomy in patients with bladder cancer. Methods. A total of 301 patients submitted to radical cystectomy at the Charité-University Hospital Berlin from 1993 to 2007 including 146 with an ileal conduit and 115 with an ileal neobladder. Clinical and pathological data as well as oncological outcome were retrospectively analyzed and compared. Quality of life was analyzed using the EORTC QLQ-C30 and BLM30 questionnaires. Results. 69.1% and 69.6% of all patients who received an ileal conduit and ileal neobladder, respectively, developed early complications. The two groups differed significantly concerning the occurrence of postoperative ileus (P=0.02) favoring patients who received an ileal conduit but not with regard to any other early-onset complication evaluated. Patients with ileal neobladder had a significantly better global health status and quality of life (P=0.02), better physical functioning (P=0.02), but also a higher rate of diarrhoea (P=0.004). Conclusion. Cystectomy with any type of diversion remains a complication-prone surgery. Even if the patient groups are not homogeneous in all respects, there are many arguments in favor of the ileal neobladder as the urinary diversion of choice.
Taiwan Junior High School Adolescents’ Epistemological Beliefs toward Mathematics and Science
Authors: Lee Chun-Yi , Yuan Yuan
Published: February 2012

Few previous studies have compared students' epistemological beliefs in mathematics with those in science. To ascertain the discipline and gender differences on students’ epistemological beliefs, this study conducted a survey with 495 Taiwanese ninth graders in junior high school. Findings show that female students express the stronger belief that science learning occurs in a quick fashion as compared with the view that mathematics learning occurs in a quick fashion , both male and female students express the stronger belief that mathematics knowledge is certain as compared with the view that science knowledge is certain, and male students express the stronger belief that science knowledge is simple and the ability to learn science is fixed as compared with the view that mathematics knowledge is simple and the ability to learn mathematics is fixed. Male students were also in more agreement in their belief about quick learning, certain knowledge, simple knowledge, and the innate ability of mathematics, as well as certain knowledge, simple knowledge, and the innate ability of science, than were female students. This study also revealed that students’ beliefs about knowledge are domain-specific, but some evidence of domain-general beliefs also exists.
Effects of different intensities of overstory thinning on tree growth and understory plant-species productivity in a semi-arid Pinus halepensis Mill. afforestation
Authors: Navarro Francisco Bruno , Jimenez M. N. , Cañadas E. M. , Gallego E. , Terrón L. , Ripoll M. A.
Published: February 2012

It is becoming more and more common in the Mediterranean basin to guard against forest fires by creating wooded firebreak areas by reducing the overstory density, pruning the remaining trees and slash mulching. Nevertheless, very few attempts have been made to analyse the effect of this practice upon tree growth and the productivity of the understory plant species in semi-arid areas by following a well defined experimental design over any length of time. To remedy this lack of information, during the spring of 2005 we thinned the overstory in a semi-arid Aleppo pine (Pinus halepensis Mill.) afforestation in SE Spain (planted in the winter of 1993-1994) from an initial density of about 1,500 trees per ha according to three different thinning regimes. The annual growth data of each stand (diameter at breast height, canopy cover and basal area) were measured in randomly situated plots of 20 × 20 m and the above-ground biomass of understory plant species was also harvested from quadrats of 0.5 × 0.5 m during the early summers of 2005 to 2009. Our results showed a positive and significant response from trees in thinned stands compared to the controls, in spite of periods of low-rainfall and plague stress that unfortunately occurred during the study period. There were also statistical differences in understory biomass production within the different areas of overstory thinning as a response to the new conditions. Nevertheless, this biomass was only a small fraction of the total above-ground biomass of the afforestation, which was much higher in control plots. These tree responses and structural changes to the afforestation could be of great interest because of their implications for forest management in the context of global change in an area where increases in temperature and reductions and irregularity in precipitation, together with higher fire risks, are forecast.
Biomass allometry and carbon factors for a Mediterranean pine (Pinus pinea L.) in Portugal
Authors: Correia Alexandra Cristina , Tomé Margarida , Carlos Pacheco , Sónia Faias , Dias Ana , Freire João , Carvalho Pedro Ochoa , Pereira João Santos
Published: February 2012

Forests play an important role in the global carbon balance because they offset a large portion of the carbon dioxide emitted through human activities. Accurate estimates are necessary for national reporting of greenhouse gas inventories, carbon credit trading and forest carbon management but in Portugal reliable and accessible forest carbon measurement methodologies are still lacking for some species. The objective of this study was to provide forest managers with a comprehensive database of carbon factors and equations that allows estimating stand-level carbon stocks in Pinus pinea L. (P. pinea), regardless of the tree inventory information available. We produced aboveground biomass and stem volume equations, biomass expansion factors (BEF) by component as well as wood basic density (WBD) and component carbon fraction in biomass. A root-to-shoot ratio is also presented using data from trees in which the root system was completely excavated. We harvested 53 trees in centre and south Portugal covering different sizes (6.5 to 56.3 cm), ages (10 to 45 years) and stand densities (20 to 580 trees ha-1). The results indicate that aboveground allometry in P. pinea is not comparable with other pines and varies considerably with stand characteristics, highlighting the need to develop stand-dependent factors and equations for local or regional carbon calculations. BEFaboveground decreases from open (1.33±0.03 Mg m-3) to closed stands (1.07±0.01 Mg m-3) due to a change in biomass allocation pattern from stem to branches. Average WBD was 0.50±0.01 Mg m-3 but varies with tree dimensions and the root-to-shoot ratio found was 0.30±0.03. The carbon fraction was statistically different from the commonly used 0.5 factor for some biomass components. The equations and factors produced allow evaluating carbon stocks in P. pinea stands in Portugal, contributing to a more accurate estimation of carbon sequestered by this forest type.
Organic Dye Design Tools for Efficient Photocurrent Generation in Dye‐Sensitized Solar Cells: Exciton Binding Energy and Electron Acceptors
Authors: Kim Bong‐Gi , Zhen Chang‐Gua , Jeong Eun Jeong , Kieffer John , Kim Jinsang
Published: February 2012

The relationship between the exciton binding energies of several pure organic dyes and their chemical structures is explored using density functional theory calculations in order to optimize the molecular design in terms of the light‐to‐electric energy‐conversion efficiency in dye‐sensitized solar cell devices. Comparing calculations with measurements reveals that the exciton binding energy and quantum yield are inversely correlated, implying that dyes with lower exciton binding energy produce electric current from the absorbed photons more efficiently. When a strong electron‐accepting moiety is inserted in the middle of the dye framework, the light‐to‐electric energy‐conversion behavior significantly deteriorates. As verified by electronic‐structure calculations, this is likely due to electron localization near the electron‐deficient group. The combined computational and experimental design approach provides insight into the functioning of organic photosensitizing dyes for solar‐cell applications. This is exemplified by the development of a novel, all‐organic dye (EB‐01) exhibiting a power conversion efficiency of over 9%.
Colorimetric Detection of Warfare Gases by Polydiacetylenes Toward Equipment‐Free Detection
Authors: Lee Jiseok , Seo Sungbaek , Kim Jinsang
Published: February 2012

Rationally designed polydiacetylene (PDA) molecules have been developed for rapid, selective, sensitive, and convenient colorimetric detection of organophosphate (OP) nerve agents, a mass destruction weapon. Oxime (OX) functionality was incorporated into diacetylene molecules to utilize its strong affinity toward organophosphates. The diacetylene molecules having an OX functional group (OX‐PDA) were self‐assembled to form PDA liposomes in an aqueous solution. Upon exposure to organophosphate nerve agent simulants, OX at the OX‐PDA liposome surface interacts with nerve agent simulants, which results in intraliposomal repulsive stress due to steric repulsion between OP‐occupied OX units at the liposome surface as well as interliposomal aggregation induced by increased hydrophobicity of the liposome surface via OP‐OX complex formation. The resulting intra‐ and interliposomal stress causes disturbance of the conjugated backbone of OX‐PDA, producing color change as a label‐free and sensitive sensory signal. The effects of molecular structure on selectivity and sensitivity of OX‐PDA liposome solution, OX‐PDA liposome‐embedded agarose gels, and OX‐PDA liposome‐coated cellulose acetate membranes were systematically investigated. The optimized OX‐PDA liposome in the solid state showed selective and rapid optical transition upon exposure down to 160 ppb of diisopropylfluorophosphate (DFP), a nerve agent simulant. The results provide an insightful molecular design principle of PDA‐based colorimetric sensor and suggest portable sensory patches for rapid, selective, sensitive, and convenient colorimetric detection of organophosphate nerve agents.
Silaindacenodithiophene‐Based Low Band Gap Polymers – The Effect of Fluorine Substitution on Device Performances and Film Morphologies
Authors: Schroeder Bob C. , Huang Zhenggang , Ashraf Raja Shahid , Smith Jeremy , D'Angelo Pasquale , Watkins Scott E. , Anthopoulos Thomas D. , Durrant James R. , McCulloch Iain
Published: February 2012

Silaindacenodithiophene is copolymerized with benzo[c][1,2,5]thiadiazole (BT) and 4,7‐di(thiophen‐2‐yl)benzo[c][1,2,5]thiadiazole (DTBT), respectively their fluorinated counter parts 5,6‐difluorobenzo[c][1,2,5]thiadiazole (2FBT) and 5,6‐difluoro‐4,7‐di(thiophen‐2‐yl) benzo[c][1,2,5]thiadiazole (2FDTBT). The influence of the thienyl spacers and fluorine atoms on molecular packing and active layer morphology is investigated with regard to device performances. bulk heterojunction (BHJ) solar cells based on silaindacenodithiophene donor‐acceptor polymers achieved PCE's of 4.5% and hole mobilities of as high as 0.28 cm2/(V s) are achieved in an organic field‐effect transistor (OFET).
Diet and Feeding Behavior of Rhinopithecus brelichi at Yangaoping, Guizhou
Authors: XIANG ZUO‐FU , LIANG WEN‐BIN , NIE SHUAI‐GUO , LI MING
Published: February 2012

Expectations of increases in human population growth and accelerated habitat loss, along with the realization that efforts to provide protection for ecosystems that sustain primates have met with limited success, make it critical that conservation plans are grounded firmly in scientific observation. Studies of the diet breadth and feeding behavior of endangered species, therefore, are critical for understanding ecological adaptations and developing a conservation strategy. The diet and feeding ecology of gray snub‐nosed monkeys (Rhinopithecus brelichi) were studied in the Fanjingshan National Nature Reserve, Guizhou, China. The monkeys were found to consume 107 different species of trees, shrubs, and ground plants from 58 genera and 28 families. Food items included young leaves, mature leaves, flowers, fruits/seeds, buds, and insects. Among these food items, there were at least 13 evergreen species of tree and liana, 3 species of grasses, and at least 2 kinds of invertebrates collected from decayed wood. Diet varied markedly throughout different seasons. Overall, diet composition (based on feeding records) was 15.3% buds, 25.5% young leaves, 21.8% mature leaves, 9.4% flowers, 21.6% fruits/seeds, and 6.3% other items. The monkeys feed mainly on young leaves and flowers in spring, unripe fruits/seeds and young leaves in summer, ripe fruits/seeds in autumn, and mature leaves and buds in winter. We propose that when inhabiting forests of lower elevation and greater vegetation complexity, R. brelichi is characterized by expanded diet breadth and includes a greater diversity of food types and plant species in its diet. One food type that appears critical to the diet of this species, especially during the winter, are the buds of Magnolia sprengeri. To protect this resource we advocate working with local communities to limit the collection of M. sprengeri, which is used in traditional Chinese medicine and has high economic value for people in the reserve. Am. J. Primatol. 74:551–560, 2012. © 2012 Wiley Periodicals, Inc.
Resorcinarene Bis‐Thiacrowns: Prospective Host Molecules for Silver Encapsulation
Authors: Salorinne Kirsi , Nauha Elisa , Nissinen Maija
Published: February 2012

Mixed‐donor atom tetramethoxy resorcinarene bis‐thiacrown hosts, in which the crown unit contains both hard oxygen and soft sulfur donor atoms, were synthesized for soft metal cation binding. The binding properties were investigated both in solution and in the solid state by NMR spectroscopy and X‐ray crystallography. It was found that the resorcinarene bis‐thiacrowns were able to complex silver cations with remarkable affinity forming readily 1:2 host–guest complexes in solution. The solid state structures also revealed that the bis‐thiacrowns form silver complexes in an unanticipated endo‐ and exo‐cavity fashion within the same host molecule. Both the solution and solid state studies indicated the sulfur atoms to be the major contributing donor atoms in forming the binding interactions with silver cations.
Integration of H2‐Selective Membrane Reactors in the Integrated Gasification Combined Cycle for CO2 Separation
Authors: Schiebahn S. , Riensche E. , Weber M. , Stolten D.
Published: February 2012

The integrated gasification combined cycle (IGCC) offers the opportunity for precombustion CO2 capture. However, recent studies using physical absorption for CO2 separation indicated efficiency penalties only slightly lower than those for postcombustion capture in conventional steam power plants. These efficiency penalties are explained and analyzed. As an alternative, a process using a so‐called water‐gas shift membrane reactor, which combines hydrogen‐selective membranes with water‐gas shift reaction, is presented. It is demonstrated that the use of recirculated flue gas from downstream of the heat recovery steam generator as membrane sweep gas results in an overall efficiency loss of only 4.5 %‐points (including CO2 compression to 120 bar) in comparison to an IGCC without carbon capture and storage (CCS).
Metallodendritic Grafted Core–Shell γ‐Fe2O3 Nanoparticles Used as Recoverable Catalysts in Suzuki CC Coupling Reactions
Authors: Rosario‐Amorin D. , Gaboyard M. , Clérac R. , Vellutini L. , Nlate S. , Heuzé K.
Published: February 2012

The use of dendritic structures for the grafting of core–shell γ‐Fe2O3/polymer 300 nm superparamagnetic nanoparticles (MNPs) has been performed with four metallodendrons that were functionalized with diphosphinopalladium complexes. The catalytic performance of these nanocatalysts was optimized for the Suzuki CC cross‐coupling reaction. These results demonstrated the importance of optimizing the catalytic efficiency of grafted MNPs by optimizing the dendritic structures and the nature of the peripheral phosphine ligands. All of these nanocatalysts showed remarkable reactivity towards bromoarenes and they were recovered and efficiently reused by magnetic separation with almost no loss of reactivity, even after 25 cycles.
Magnetic Bistability of Isolated Giant‐Spin Centers in a Diamagnetic Crystalline Matrix
Authors: Vergnani Luca , Barra Anne‐Laure , Neugebauer Petr , Rodriguez‐Douton Maria Jesus , Sessoli Roberta , Sorace Lorenzo , Wernsdorfer Wolfgang , Cornia Andrea
Published: February 2012

Polynuclear single‐molecule magnets (SMMs) were diluted in a diamagnetic crystal lattice to afford arrays of independent and iso‐oriented magnetic units. Crystalline solid solutions of an Fe4 SMM and its Ga4 analogue were prepared with no metal scrambling for Fe4 molar fractions x down to 0.01. According to high‐frequency EPR and magnetic measurements, the guest SMM species have the same total spin (S=5), anisotropy, and high‐temperature spin dynamics found in the pure Fe4 phase. However, suppression of intermolecular magnetic interactions affects magnetic relaxation at low temperature (40 mK), where quantum tunneling (QT) of the magnetization dominates. When a magnetic field is applied along the easy magnetic axis, both pure and diluted (x=0.01) phases display pronounced steps at evenly spaced field values in their hysteresis loops due to resonant QT. The pure Fe4 phase exhibits additional steps which are firmly ascribed to two‐molecule QT transitions. Studies on the field‐dependent relaxation rate showed that the zero‐field resonance sharpens by a factor of five and shifts from about 8 mT to exactly zero field on dilution, in agreement with the calculated variation of dipolar interactions. The tunneling efficiency also changes significantly as a function of Fe4 concentration: the zero‐field resonance is significantly enhanced on dilution, while tunneling at ±0.45 T becomes less efficient. These changes were rationalized on the basis of a dipolar shuffling mechanism and transverse dipolar fields, whose effect was analyzed by using a multispin model. Our findings directly prove the impact of intermolecular magnetic couplings on SMM behavior and disclose the magnetic response of truly isolated giant spins in a diamagnetic crystalline environment.
Optimal Percoll concentration facilitates flow cytometric analysis for annexin V/propidium iodine‐stained ischemic brain tissues
Authors: Juan Wei‐Sheng , Lin Hsiao‐Wen , Chen Ying‐Hsin , Chen Hung‐Yi , Hung Yu‐Chang , Tai Shih‐Huang , Huang Sheng‐Yang , Chen Tsung‐Ying , Lee E‐Jian
Published: February 2012

We sought to determine the optimal Percoll concentration for ischemic rat brain prepared for flow cytometric (FC) measurements. Animals were subjected to the right middle cerebral artery (MCA) occlusion, and were euthanized at 3, 12, 24, and 72 h after reperfusion onset. The brains were processed by different concentrations (unisolated, 20, 25, 30, or 40%) of Percoll and stained with annexin V/propidium iodine (PI). Ischemic brain damage was evaluated by FC analysis and image analysis for histologic sections. The relative susceptibility of different phenotypes of cells to necrotic and apoptotic damage were evaluated by the FC analyses for the immunohistochemistry, PI, and the terminal deoxynucleotidyl transferase‐mediated deoxyuridine triphosphate nick‐end labeling (TUNEL)‐processed brain tissues. Our results showed that FC analysis effectively detected the extent and maturation of apoptotic/necrotic brain damage, and the results were consistent with those determined from histologic brain sections. Neuron was more vulnerable to apoptosis than glia, whereas both cellular phenotypes were compatible in susceptibility for necrotic cell death. Percoll at a low concentration (20%) could effectively remove tissue debris without affecting membranous integrity of the injured neurons. Conversely, high percentages of Percoll (30–40%) substantially increased membranous damage for the injured cells. These results supported the application of FC to determine the extent and progression in time, as well as relative phenotypes of apoptotic/necrotic cell deaths following ischemic damage. We highlighted the use of Percoll at low percentages to facilitate the removal of tissue debris and to improve membrane integrity preservation for the injured neurons. © 2012 International Society for Advancement of Cytometry.
Distributed key management scheme for peer‐to‐peer live streaming services
Authors: Li Jung‐Shian , Hsieh Che‐Jen , Wang Yu‐Kai
Published: February 2012

Live media streaming over peer‐to‐peer (P2P) network structures is commonplace nowadays. However, with the large number of users in a typical P2P system, it is impractical to use the central server to process the key information update requests of all the users Accordingly, the present study proposes a distributed key management scheme in which the server is only required to transmit the key update information to a limited number of users. To further reduce the load on the server, the update information is distributed using a hop‐by‐hop approach. An effective method is proposed for protecting the key update information as it is propagated through the network. In addition, a technique is presented for ensuring the security of the certificates used in the system It is shown that the distributed key management scheme and authentication procedure ensure an efficient and secure P2P live streaming performance even in the event of high churn rates. Copyright © 2012 John Wiley & Sons, Ltd.
Bis‐ and Tris‐Alkyne Phosphoramidites for Multiple 5′‐Labeling of Oligonucleotides by Click Chemistry
Authors: Ligeour Caroline , Meyer Albert , Vasseur Jean‐Jacques , Morvan François
Published: February 2012

Three new phosphoramidites exhibiting two or three alkyne functions were prepared and introduced at the 5′ end of oligonucleotides. The resulting bis‐ and tris‐alkyne oligonucleotides were conjugated with acetylthiohexyl, ferrocenecarboamide hexyl, or carbohydrate‐propyl azides by using click chemistry (CuAAC) to afford polyconjugated oligonucleotides. Conjugations were performed either in solution or on solid support with high efficiency.
A Mercury‐Free Sensor to Control Trace Metal Ionization Used to Treat Pathogens in Water Distribution Systems
Authors: Voccia Diego , Laschi Serena , Palchetti Ilaria , Marrazza Giovanna , Mascini Marco
Published: February 2012

The specific aim of this work was the development of an electroanalytical method, based on a mercury‐free sensor, for the determination of silver(I) and copper(II) used to treat pathogens in water distribution systems. Analysis of the two metals was performed in 0.1 M ammonia solution pH 9.0 using Square Wave Anodic Stripping Voltammetry (SWASV). The proposed method is based on the determination of copper, the addition of a masking agent (EDTA) to the solution and afterwards the determination of silver. A detection limit of 23 µg/L and 6 µg/L for 60 s of deposition time was obtained for copper and silver, respectively. Analysis of water samples was also reported.
Charring rates for double beams made from laminated veneer lumber (LVL)
Authors: Tsai Kevin , Carradine David , Moss Peter , Buchanan Andrew
Published: February 2012

This paper examines charring rates for different cross‐sections of single and double timber beams made from laminated veneer lumber, with nailed, screwed or glued connection types for the double beams. Charring rates and burning characteristics were examined both in a small furnace and in a larger pilot furnace. The bottom charring rates were sometimes greater than the side charring rates for very narrow beams dominated by corner effects and for double beams where the two components could separate during the fire exposure. The nail‐connected double laminated veneer lumber beams experienced the largest separation, leading to charring between the two components. The best performance was from the glued connection, which showed similar charring rates as a solid timber beam. Both the large‐scale and small‐scale testing showed that suitably placed screws (preferably full‐length threaded) can be used to give almost the same performance as a glued connection. Experimental findings were compared with results from a finite element analysis. There was reasonable agreement while the char layer was small, but less agreement in later stages as the char layer increased in thickness. Experimental findings were used to modify a spreadsheet design tool that predicts the fire resistance of a timber–concrete composite floor. Copyright © 2012 John Wiley & Sons, Ltd.
VALUING THE ECONOMIC BENEFITS OF COMPLEX INTERVENTIONS: WHEN MAXIMISING HEALTH IS NOT SUFFICIENT
Authors: Payne Katherine , McAllister Marion , Davies Linda M.
Published: February 2012

Complex interventions, involving interlinked packages of care, challenge the application of current methods of economic evaluation that focus on measuring only health gain. Complex interventions may be problematic on two levels. The complexity means the intervention may not fit into one of the current appraisal systems, and/or maximising health is not the only objective. This paper discusses the implications of a programme of work that focused on clinical genetics services, as an example of a complex intervention, and aimed to identify the following: the attributes that comprise both health and non‐health aspects of benefits and whether it is possible to evaluate such an intervention using current National Institute for Health and Clinical Excellence appraisal processes. Genetic services and tests are a good example of a complex intervention and have broader objectives than just health gain, which may usefully be measured using the concept related to capability, which we have called ‘empowerment’. Further methodological work is required to identify the trade‐off between non‐health (empowerment) and health benefits for other complex interventions. We do not advocate a move away from QALY maximisation but do suggest that there is a need for a more considered approach that can take account of the perceived value for non‐health attributes for some complex interventions. Copyright © 2012 John Wiley & Sons, Ltd.