bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of antioxidants in vegetable insulating oils by HPLC
Authors: Fang Yuan , Luo Yunbai , Yu Ping
Published: June 2016

Vegetable insulating oils (VIOs) have attracted wide attention for their high flash point, high insulation performance and degradability. However, the unsaturated fatty acids contained in VIOs reduce their oxidation stability, which requires the addition of some antioxidants to ensure their usage. Here, we establish a high-performance liquid chromatography (HPLC) method for determination of antioxidants in VIOs. The standard calibration curves of 3 analytes (PG, BHA, BHT) all show high linearity, and the correlation coefficients are all above 0.9994. Limits of detection of all three analytes range from 0.003 to 0.010 mg/ml; limits of quantitation range from 0.010 to 0.033 mg/ml. The new HPLC method is proved ideally suitable for the analysis of commercialized transformer oil Cooper-FR3 with precision (%RSD = 0.3%–0.7%) and accuracy (%recovery = 100.0%–102.1%), suggesting that this method is an efficient tool for routine screening of antioxidant contents in VIOs. We used this method to monitor the changes of antioxidant contents in the oxidation of two VIOs–soybean oil and rapeseed oil.
Nonlinear features of electrostatic waves in a plasma with nonthermal-Tsallis distributed electrons
Authors: Dutta Debjit , Sahu Biswajit
Published: June 2016

Linear and nonlinear properties of electrostatic waves are investigated in an unmagnetized multicomponent plasma system consisting of cold and hot electrons obeying nonthermal-Tsallis distribution and warm ions using the Sagdeev pseudopotential technique. It is found that such a plasma supports soliton, supersoliton, and double layer structures. Also, the present plasma system supports the coexistence of arbitrary amplitude compressive and rarefactive solitons in a certain region of parameter space. Furthermore, numerical results reveal that the nonthermal-Tsallis distribution of electrons may affect the spatial profiles as well as the nature of the electrostatic nonlinear structures.
Optimising beef business performance in northern Australia: what can 30 years of commercial innovation teach us?
Authors: Walsh Dionne , Cowley Robyn
Published: June 2016

This paper evaluates three decades of innovation by a leading beef producer in the Barkly region of the Northern Territory. The case study represents a rare published analysis of changes in production, greenhouse gas emissions and land condition metrics for a commercial livestock business. Thirty years ago the property was under-developed and had poor livestock productivity by today’s standards. Between 1981 and 2013, the business has increased carrying capacity through water point development, and achieved a >50% increase in herd size, a 46% improvement in weaning rate, an 82% reduction in breeder mortality rate and an improvement in land condition. Annual liveweight turn-off has increased from 75 kg to 128 kg per adult equivalent (AE) carried. All of this has been achieved while using recommended stocking rates. In contrast, two additional analyses reflecting other management approaches being taken by some north Australian beef businesses resulted in poor productivity, economic, emissions and land condition outcomes. Total greenhouse gas emissions have increased on the case study property since 1981 as a result of increasing herd size. However, the intensity of emissions per tonne of liveweight sold has declined by 43% due to the improvements in livestock productivity. The potential for generating carbon revenue from this emissions intensity improvement was explored. We found that for >95% of northern beef enterprises, current project transaction costs would entirely negate carbon revenue at a carbon price of < $25 tCO2e–1. At $5 tCO2e–1, the minimum herd size needed to cover the project transaction costs would be in excess of 35 000 AE. Although substantial carbon profits appear unlikely at present, the management practices evaluated can deliver substantial economic, emissions and land condition benefits to individual businesses and the wider industry. The paper concludes that cost-effective investment to concurrently increase herd size and livestock productivity per head, in conjunction with safe stocking rate management, is a proven path to economic and environmental sustainability in the north Australian beef industry.
The effect of soil and pasture attributes on rangeland infiltration rates in northern Australia
Authors: Fraser G. W. , Stone G. S.
Published: June 2016

Surface runoff is an important factor affecting rangeland pasture productivity and off-site sediment transportation. The application of rangeland biophysical models including sub-models of runoff and erosion provides one method to assess how management and climate variability affect the frequency and quantity of surface runoff events. However, there is often limited confidence in extrapolating runoff models developed from site-specific, hillslope field experiments to other locations due to variation in soil types and land condition states. To improve rangeland runoff models, we investigated three potentially important components at 18 paired land condition sites: (1) the importance of a variety of pasture attributes such as biomass and cover on infiltration rates; (2) the impact of surface soil texture on infiltration rates; and (3) whether soil carbon and/or soil bulk density provide valuable indicators of a site’s infiltration rates.
The study found that surface soil texture was important when aboveground biomass was low and was found to have a ‘broken-stick’ relationship with infiltration rates (i.e. lowest infiltration occurred at the pivot point of 64% sand). Aboveground biomass, (which included standing grass, grass litter and tree litter) was the best soil or pasture attribute for predicting a plot’s infiltration capacity accounting for 68% of the variability. Plots with surface soil sand content greater than 60% and which had been exclosed for between 4 and 24 years had higher average surface soil carbon mass and concentration (~10%) than adjacent grazed plots. The exclosed plots also had higher surface soil porosity, which was associated with very high infiltration rates.
Climate Clever Beef: options to improve business performance and reduce greenhouse gas emissions in northern Australia
Authors: Bray Steven , Walsh Dionne , Phelps David , Rolfe Joe , Broad Kiri , Whish Giselle , Quirk Michael
Published: June 2016

The Rangeland Journal – Climate Clever Beef special issue examines options for the beef industry in northern Australia to contribute to the reduction in global greenhouse gas (GHG) emissions and to engage in the carbon economy. Relative to its gross value (A$5 billion), the northern beef industry is responsible for a sizable proportion of national reportable GHG emissions (8–10%) through enteric methane, savanna burning, vegetation clearing and land degradation. The industry occupies large areas of land and has the potential to impact the carbon cycle by sequestering carbon or reducing carbon loss. Furthermore, much of the industry is currently not achieving its productivity potential, which suggests that there are opportunities to improve the emissions intensity of beef production. Improving the industry’s GHG emissions performance is important for its environmental reputation and may benefit individual businesses through improved production efficiency and revenue from the carbon economy. The Climate Clever Beef initiative collaborated with beef businesses in six regions across northern Australia to better understand the links between GHG emissions and carbon stocks, land condition, herd productivity and profitability. The current performance of businesses was measured and alternate management options were identified and evaluated. Opportunities to participate in the carbon economy through the Australian Government’s Emissions Reduction Fund (ERF) were also assessed. The initiative achieved significant producer engagement and collaboration resulting in practice change by 78 people from 35 businesses, managing more than 1 272 000 ha and 132 000 cattle. Carbon farming opportunities were identified that could improve both business performance and emissions intensity. However, these opportunities were not without significant risks, trade-offs and limitations particularly in relation to business scale, and uncertainty in carbon price and the response of soil and vegetation carbon sequestration to management. This paper discusses opportunities for reducing emissions, improving emission intensity and carbon sequestration, and outlines the approach taken to achieve beef business engagement and practice change. The paper concludes with some considerations for policy makers.
Focus in Indian English and Hindi late and simultaneous bilinguals
Authors: Puri Vandana
Published: June 2016

The main objective of this study is to investigate the acoustic correlates of focus in late and simultaneous bilinguals of Hindi and Indian English (IE). The main acoustic correlates of focus in American/British English are duration, amplitude and F0 and in Hindi are duration, F0 excursion and post-focal pitch compression. In the present study, I look at duration, RMS amplitude and F0 excursion in broad focus, narrow focus and post-focus declarative present tense, past tense and perfect aspect (both transitive and intransitive verbs) Hindi and IE sentences, to explore if there are any differences in the two bilingual groups and to understand the acoustic correlates of focus in IE and Hindi.
Does bilingualism protect against cognitive aging?
Authors: Watson Caitlin Wei-Ming , Manly Jennifer J. , Zahodne Laura B.
Published: June 2016

Recent studies of bilingualism as a protective factor in cognitive aging have reported conflicting findings, and researchers have begun to explore the methodological complications that may explain differences across studies. This article details the current research landscape and addresses several issues relevant to the study of bilingualism and late-life cognitive function: study design, establishing causal relationships, confounding factors, operationalizing bilingualism, predicting cognitive level versus cognitive change, and incorporating brain structural variables to interrogate cognitive reserve.
Putting together bilingualism and executive function
Authors: Valian Virginia
Published: June 2016

Three important issues bear on understanding the connection between bilingualism and executive function. The first is the absence of a fine-grained task analysis for executive functions and other cognitive processes. The second is the absence of a theory of the cognitive mechanisms underlying the deployment of two or more languages and thus the absence of a solid basis on which to make predictions about what domain-general performances, if any, bilinguals should excel in. The third is the relation between neural and behavioral consequences of bilingualism. These three issues must be taken in account in trying to understand the variability among findings showing benefits of bilingualism for executive function.
Growth and Fatty Acid Composition of Two Strains of Arctic Char Fed Diets Formulated with Low Fish Oil Inclusion in a Recirculating Aquaculture System
Authors: Burr Gary S , Wolters William R , Barrows Frederic T
Published: June 2016

Arctic Char Salvelinus alpinus is a highly desirable species for aquaculture due to their fast growth, culture conditions, and reputation as a sustainably produced fish as a result of closed containment culture. A study was conducted to evaluate performance and highly unsaturated fatty acid retention in two Arctic Char stocks—one commercial stock and one from the U.S. Department of Agriculture (USDA)—fed one of three diets containing different lipids (27% total): 11% fish oil and 11% soy–canola (diet 1, reference diet), 5% fish oil and 18% canola oil (diet 2), and 5% fish oil and 17% poultry oil (diet 3). Protein sources did not vary among the diets, and the lipid sources for the reference diet were similar to those included in commercial grower diets. After 250 d, fish from the USDA stock (1,736 ± 28 g [mean ± SE]) had significantly higher average weight, approximately 510 g greater, compared with the commercial stock (1,226 ± 19 g). Average weight gain was not significantly different among the diets but tended to be higher in diet 2 (P = 0.09), and the USDA stock (~1,409 ± 27 g gained) had higher average weight gain compared with the commercial stock (~924 ± 18 g gained). Specific growth rate (SGR) was significantly different among the diets; fish fed diet 2 had the highest growth rate (0.62%/d compared with 0.59%/d and 0.58%/d for the other two diets) and the USDA stock had a significantly higher SGR compared with the commercial stock (0.65 ± 0.01%/d compared with 0.54 ± 0.01%/d). Fillet yield did not vary among diets or stocks. The average fillet yield was 67.4% of the gutted weight and 62.2% of the total weight. Selected fatty acid profiles did vary by stock and all fatty acid profiles showed dietary effects. The USDA stock had superior growth, and diet had the greatest influence on the fatty acid profile of the fillets.
Combining incidence and demographic modelling approaches to evaluate metapopulation parameters for an endangered riparian plant
Authors: Charney Noah D. , Record Sydne
Published: June 2016

Metapopulations are a central concept in ecology and conservation biology; however, estimating key parameters such as colonization rates presents a substantial obstacle to modelling metapopulations in many species. We develop spatial and non-spatial simulation models that combine incidence- and demographic-based approaches to build a relationship between observed patch occupancy, habitat turnover rates, colonization rates and dispersal scales. Applying these models to long-term observations of Pedicularis furbishiae (Furbish’s lousewort), a rare plant endemic to the Saint John River, we predict that observed habitat patches averaging 550 m in length receive colonizing seedlings with a yearly probability of 0.45 or 0.54, based on two different models. Predictions are consistent with a standard analytic metapopulation formulation modified to partition extinction drivers during the early and the late phases of a population’s life cycle. While the specific results rest on several simplifying assumptions, the models allow us to understand the impact that increasing rates of habitat turnover would have on the future survival of this species.
Two strategies by epiphytic orchids for maintaining water balance: thick cuticles in leaves and water storage in pseudobulbs
Authors: Yang Shi-Jian , Sun Mei , Yang Qiu-Yun , Ma Ren-Yi , Zhang Jiao-Lin , Zhang Shi-Bao
Published: June 2016

Epiphytes are an important component of tropical and subtropical flora, and serve vital ecological functions in forest hydrology and nutrient fluxes. However, they often encounter water deficits because there is no direct contact between their roots and the soil. The strategies employed by epiphytes for maintaining water balance in relatively water-limited habitats are not completely understood. In the present study, we investigated the anatomical traits, water loss rates, and physiology of leaves and pseudobulbs of four Dendrobium species with different pseudobulb morphologies to understand the roles of leaf and pseudobulb in maintaining water balance of epiphytic orchids. Our results showed that two species ( D. chrysotoxum and D. officinale ), with lower rates of water loss, have thicker leaves and upper cuticles, but lower epidermal thickness and leaf dry mass per area. In contrast, the other two species ( D. chrysanthum and D. crystallinum ) with thinner cuticles and higher rates of water loss, have less tissue density and greater saturated water contents in their pseudobulbs. Therefore, our results indicate that these latter two species may resist drought by storing water in the pseudobulbs to compensate for their thin cuticles and rapid water loss through the leaves. Under the same laboratory conditions, excised pseudobulbs with attached leaves had lower rates of water loss when compared with samples comprising only excised leaves. This implies that epiphytic orchids utilize two different strategies for sustaining water balance: thick cuticles to conserve water in leaves and water storage in pseudobulbs. Our results also show that Dendrobium species with thin cuticles tend to have pseudobulbs with high water storage capacity that compensates for their faster rates of water loss. These outcomes contribute to our understanding of the adaptive water-use strategies in Dendrobium species, which is beneficial for the conservation and cultivation of epiphytic orchids.
Rapid increase in growth and productivity can aid invasions by a non-native tree
Authors: Dudeque Zenni Rafael , Lacerda da Cunha Wanderson , Sena Guilherme
Published: June 2016

Research on biological invasions has produced detailed theories describing range expansions of introduced populations. However, current knowledge of evolutionary factors associated with invasive range expansions, especially those related to rapid evolution of long-lived organisms, is still rudimentary. Here, we used a system of six 40-year-old invasive pine populations that originated from replicated introduction events to study evolution in productivity, growth, and chemical defence traits. We tested the hypotheses that invasive populations were undergoing rapid phenotypic change as populations spread, that populations exhibit trade-offs between evolution in growth and chemical defences, and that rates of rapid evolution in plant growth and productivity effect rates of invasion. Although all invasions started from replicated pools of genetic material and equal propagule pressure, we found divergence in mean values for the six invasive populations in the six traits measured. Not only were there between-population variations but also invasive populations were also rapidly changing along each invasive population expansion. Two populations displayed greater leaf areas (LAs) and smaller specific LAs (SLAs) during range expansion. Four populations had faster growth rates at the leading edge of the invasion front in comparison with plants at the rear edge. In terms of total plant defences, non-volatile resin increased in plants along one invasion gradient and decreased in a second, total needle phenolics increased in plants along one invasion gradient and total wood phenolics increased in plants along the one invasion gradient and decreased in a second. We found no trade-offs between investments in growth and chemical defence. Also, faster rates of change in growth rate and LA were positively associated with greater dispersal distances of invasive populations, suggesting rapid evolution may increase invasiveness. Understanding the roles of both natural and human-mediated ecological and evolutionary processes in population-level dynamics is key to understanding the ability of non-native species to invade.
PEP_scaffolder: using (homologous) proteins to scaffold genomes
Authors: Zhu Bai-Han , Song Ying-Nan , Xue Wei , Xu Gui-Cai , Xiao Jun , Sun Ming-Yuan , Sun Xiao-Wen , Li Jiong-Tang
Published: June 2016

Motivation: Recovering the gene structures is one of the important goals of genome assembly. In low-quality assemblies, and even some high-quality assemblies, certain gene regions are still incomplete; thus, novel scaffolding approaches are required to complete gene regions.

Results: We developed an efficient and fast genome scaffolding method called PEP_scaffolder, using proteins to scaffold genomes. The pipeline aims to recover protein-coding gene structures. We tested the method on human contigs; using human UniProt proteins as guides, the improvement on N50 size was 17% increase with an accuracy of ∼97%. PEP_scaffolder improved the proportion of fully covered proteins among all proteins, which was close to the proportion in the finished genome. The method provided a high accuracy of 91% using orthologs of distant species. Tested on simulated fly contigs, PEP_scaffolder outperformed other scaffolders, with the shortest running time and the highest accuracy.

Availability and Implementation: The software is freely available at http://www.fishbrowser.org/software/PEP_scaffolder/

Contact:  lijt@cafs.ac.cn

Supplementary information:  Supplementary data are available at Bioinformatics online.
Microbial community and its potential as descriptor of environmental status
Authors: Caruso Gabriella , Azzaro Maurizio , Caroppo Carmela , Decembrini Franco , Monticelli Luis Salvador , Leonardi Marcella , Maimone Giovanna , Zaccone Renata , La Ferla Rosabruna
Published: June 2016

Planktonic communities hold a relevant role within the EU Marine Strategy Framework Directive (MSFD). In view of reaching the Good Environmental Status of marine ecosystems, within this Directive the phyto- and zooplanktonic communities have received great attention, while Prokaryotes (Bacteria, Archaea, and Cyanobacteria) have been neglected. Indeed, the relevance of microbes (particularly of the faecal pollution indicators) as water quality indicators, the role that microorganisms play within the biogeochemical fluxes and in the whole ecosystem functioning, are all important features that deserve to be focused within the MSFD. The present study aims at reviewing the main issues where prokaryotic variables find useful application as descriptors of environmental status, trying to develop a panel of prokaryotic indicators suitable for the environmental quality assessment. From a survey of scientific literature and on field datasets, prokaryotic abundance and activities (enzymatic hydrolysis, prokaryotic production, and respiratory rates) are here chosen as early warning sentinels to detect changes in environmental quality, using an integrated approach with trophic (chlorophyll-a, particulate and dissolved organic matter) measurements.
Individual variation in mule deer (Odocoileus hemionus) habitat and home range in the Chihuahuan Desert, Mexico
Authors: Pérez-Solano Luz Adriana , Gallina-Tessaro Sonia , Sánchez-Rojas Gerardo
Published: June 2016

Historically, mule deer (Odocoileus hemionus) had a distribution area as large as the Chihuahuan Desert in Mexico, but in recent years, its populations have decreased and distribution areas have become isolated. This species exhibits a high degree of intraspecific variation in its use of habitat resources and home range size. In the Mapimí Biosphere Reserve, where the southernmost population of mule deer is located, over the course of 3 years, 7 females and 1 young male mule deer were monitored using radiotelemetry. Based on the deer location data, home range and habitat use were estimated for each deer. The mean (± SD) home range size for females was 14.70 km2 (± 5.89), the home range of the male was 18.05 km2. These estimates are among the smallest reported for the species. During the dry season, the use of certain topographic characteristics of the habitat was more similar among the individual deer than it was during the rainy season. The group of deer we sampled did not show preference for any particular type of vegetation, but rather used the majority of plant associations, depending on their availability. Preference was only exhibited by individual deer. The young male made use of the habitat similar to that of most of the females.

El venado bura (Odocoileus hemionus) históricamente tenía un área de distribución tan grande como el Desierto Chihuahuense de México, sin embargo, en los últimos años sus poblaciones y áreas de distribución se han visto reducidas y aisladas. Se sabe que la especie exhibe gran variación intraespecífica en el uso de los recursos del hábitat y en los ámbitos hogareños. Dentro de la Reserva de Biosfera de Mapimí donde se encuentra la población más sureña de los venados buras, a lo largo de 3 años se monitorearon mediante radiotelemetría, 7 hembras y 1 macho joven de venado bura. Utilizando las localizaciones se estimaron los ámbitos hogareños y el uso del hábitat de cada animal. El promedio (± DE) del tamaño del ámbito hogareño para las hembras fue de 14.70 km2 (± 5.89), el tamaño del ámbito hogareño del macho fue de 18.05 km2. Estas estimaciones son de las áreas más pequeñas reportadas para la especie. Durante la temporada de secas el uso de las características topográficas del hábitat entre individuos fue más parecido entre ellos que en lluvias. Entre el conjunto de venados que muestreamos, no se presentó preferencia por alguna asociación vegetal en particular, los individuos usan la mayoría de las asociaciones vegetales de acuerdo a su disponibilidad, las preferencias únicamente se observaron a nivel individual. El macho joven hizo un uso del hábitat similar al que hicieron la mayoría de las hembras.
Pediatric EEG
Authors: Nickels Katherine C.
Published: June 2016

Electroencephalography (EEG) is an important part of the evaluation of many disorders in infants and children, including seizures, spells, transient central nervous system (CNS) symptoms, behavioral disorders, altered states of consciousness, and lesions or conditions resulting in a disturbance of cerebral function. As in adults, abnormal EEGs in children can be helpful in diagnosing epileptic vs. non-epileptic spells, determining the degree and extent of disturbance of cerebral function, and identifying underlying etiologies for neurological symptoms. This chapter discusses the normal developmental patterns in preterm infants, term neonates, infants, and children. Knowledge of the normal EEG patterns and how they change with maturation is essential in order to accurately interpret the EEG. Without this understanding, normal patterns may be erroneously thought of as abnormal, or abnormal patterns may be missed, leading to improper diagnosis and treatment of the child.
Repetitive Nerve Stimulation Studies
Authors: Kennelly Kathleen D.
Published: June 2016

Repetitive stimulation is a technique that evaluates the function of the neuromuscular junction. It is important not only in the detection, clarification, and follow-up of neuromuscular junction diseases, but also in excluding these disorders in patients with symptoms of fatigue, vague weakness, diplopia, ptosis, and malaise, or with objective weakness of uncertain origin. The technique requires knowledge of the physiology and pathophysiology of neuromuscular transmission and the basic techniques of nerve conduction studies. This chapter includes a brief review of the anatomy and physiology of the neuromuscular junction as it applies to repetitive stimulation, a detailed discussion of the technique, the pitfalls that can occur if not carried out correctly, criteria used to classify the results as normal or abnormal, the patterns of abnormalities that can be seen, and the clinical correlation of those abnormalities with the various different disorders of neuromuscular transmission.
Technical Issues and Potential Complications of Nerve Conduction Studies
Authors: Rubin Devon I.
Published: June 2016

Nerve conduction studies (NCS) provide important information in the evaluation of patients with suspected neuromuscular disorders. While NCS techniques are fairly standardized and often straightforward in experienced hands, they are fraught with a variety of potential technical problems that may interfere with accurate and reliable acquisition of information. Recognition, identification, and correction of technical problems are critical to the reliable interpretation of any electrodiagnostic study. NCS are safe to perform, but they involve the administration of electrical current to the patient and may pose some potential risks in certain clinical circumstances. This chapter will review the technical problems that may occur during the performance of NCS and review the potential risks of NCS.
Needle Electromyography
Authors: Rubin Devon I.
Published: June 2016

Needle EMG complements nerve conduction studies in the evaluation of patients with suspected neuromuscular disorders. It requires an understanding of the physiology of muscle fibers and motor units, and is dependent on mastering the skills of data collection and understanding the changes that occur with the many disorders that may affect peripheral nerves, neuromuscular junctions, and muscle. The essence of quality needle EMG rests with the ability to isolate, recognize, and interpret the wide range of specific waveforms and their variation that occur in normal and diseased muscle. The nature and meaning of spontaneously firing potentials and the alteration in appearance and firing pattern of MUPs in each muscle tested are the data on which a clinical interpretation is based. This chapter will review the basics of performing needle electromyography and discuss the identification and interpretation of various EMG waveforms that are recorded at rest and during voluntary contraction.
Evaluation of Adrenergic Function
Authors: Low Phillip A.
Published: June 2016

Peripheral adrenergic function is important in the maintenance of postural normotension. It may be impaired in peripheral neuropathies, and this may be manifested as alterations in acral temperature, color, or sweating. Simple, accurate, and reproducible tests of peripheral adrenergic function are now routinely used in clinical autonomic laboratories. For noninvasive evaluation of autonomic function, tests of peripheral adrenergic function can be used to separately evaluate the vagal and adrenergic components of baroreflex sensitivity. The vagal component is derived from the heart period response to blood pressure change and the adrenergic component by the blood pressure recovery time in response to the preceding fall in blood pressure, induced by the Valsalva maneuver.This chapter describes methods used to determine peripheral adrenergic function and their value and shortcomings.
Long Latency Reflexes and the Silent Period
Authors: van Gerpen Jay A. , Caviness John N.
Published: June 2016

Long latency reflexes (LLRs) are EMG activity occurring during the transition from reflex to voluntary motor activity, which probably arise from a transcortical loop, including afferents within the dorsal column/medial lemniscal system to the sensorimotor cortex and corticospinal tract efferents. Depending upon the site of a lesion and its pathophysiology, LLRs may be absent, delayed, or enhanced. In disorders of cortical hyperexcitability, including cortical myoclonus, an LLR occurring 40–60 ms after stimulation of the median nerve at rest may be present (“C-reflex.”) In response to noxious stimuli to the lower extremities, a polysynaptic network of spinal neurons, flexor reflex afferents, induce a patterned withdrawal response, including hip and knee flexion. These flexor reflexes may aid in the diagnosis of disorders of spinal cord hyperexcitability. Normally, following high stimulation of a peripheral nerve innervating a muscle that is being strongly contracted, no electrical activity occurs for approximately 100 ms (“silent period.”_ In disorders of distal peripheral nerve or muscle hyperexcitability, the silent period may be absent.
Electrophysiology Testing of Movement Disorders
Authors: Caviness John N. , van Gerpen Jay A. , Klassen Bryan T. , Bower James H. , Matsumoto Joseph Y.
Published: June 2016

A battery of tools is used to provide neurophysiological characteristics of movement disorders, including EMG, EEG, EEG-EMG with back-averaging, evoked potentials, and long-latency EMG reflexes. Surface EMG forms the foundation of movement neurophysiology and can clarify muscle discharge timing and spatial relationships, as well as frequency information. This is useful for distinguishing tremor types, tremor versus myoclonus, and which muscles are involved in dystonia. Common modalities that are simultaneously recorded with EMG are EEG and motion detectors. Combined EMG with EEG recordings during myoclonus is useful for myoclonus classification and source localization. Evoked potentials and long-latency reflexes can assist with defining the myoclonus pathophysiology. These tests can distinguish between myoclonus of cortical versus subcortical origin, which affects treatment strategy decisions. EMG is useful for muscle localization for botulinum toxin injection. Chorea, tics, and psychogenic movement disorders mostly show nonspecific EMG patterns, limiting the usefulness of the technique in these situations.
Deep Brain Stimulation Electrophysiology
Authors: Klassen Bryan T.
Published: June 2016

Deep brain stimulation (DBS) is a therapy for medically refractory movement disorders, and the indications for DBS are likely to expand to other neurological and psychiatric diseases. DBS involves the delivery of electrical current to specific brain targets using a permanently implantable stimulating electrode that is surgically placed under stereotactic guidance. The efficacy and side effects of DBS are directly related to the position of the implantable stimulating electrode. While current imaging modalities help define an initial trajectory to the target region, most centers also rely on neurophysiological confirmation of electrode position. High-impedance microelectrode recording can define both spontaneous and stimulus-evoked firing patterns of the cells along the lead’s trajectory. By comparing these findings to those expected, one can determine whether the electrode’s final position is as intended. The effects encountered during intraoperative test stimulation delivered through the implanted electrode further define the accuracy of positioning. Stimulation parameters can be refined in the outpatient setting in order to provide the maximum benefit and least side effects.
Assessment of Sleep and Sleep Disorders
Authors: Silber Michael H. , Harris Cameron D.
Published: June 2016

This chapter reviews the techniques that are available to study sleep as well as disorders that may occur during sleep. Multiple physiological parameters can be assessed using one or a combination of polysomnography, multiple sleep latency, or maintenance of wakefulness tests, as well as actigraphy and portable monitoring. The use of these tests is helpful to not only identify different stages of sleep, but to assess sleep disorders, such as sleep apnea, other disorders manifesting with excessive somnolence, and parasomnias. The field of sleep medicine and the associated sleep neurophysiology continues to grow and expand our understanding of sleep-related disorders.
Brain Stem Auditory Evoked Potentials in Peripheral Acoustic Disorders
Authors: Bauch Christopher D. , Olsen Wayne O.
Published: June 2016

Brain stem auditory evoked potentials (BAEPs) testing is a useful technique for the otoneurological assessment of patients with complaints of dizziness/imbalance, hearing loss, or tinnitus. The BAEP evaluation records neuroelectric potentials from cranial nerve (CN) VIII and the ascending brain stem pathways that are elicited as a response to brief auditory stimuli. BAEPs are performed in conjunction with audiology testing since conductive hearing losses as well as sensorineural disorders can affect BAEP waveform morphology and latencies. Overall sensitivity of BAEP is over 90% for patients with a CN VIII tumor, and the false-positive rate for patients having cochlear hearing loss is 12%. This chapter reviews BAEPs in the assessment of peripheral acoustic disordes and also discusses auditory neuropathy spectrum disorder and cochlear mocrophonic assessment as an additional electrophysiological method.
Inhaled peppermint oil for postop nausea in patients undergoing cardiac surgery
Authors: Briggs Patricia , Hawrylack Helen , Mooney Ruth
Published: June 2016

Background.

Postoperative nausea is a common occurrence that is very uncomfortable for patients and may result in complications including pain, strain at the surgical site, aspiration, and possible dehiscence. Antiemetics used to manage the nausea cause many adverse reactions, such as dysrhythmias and/or drowsiness resulting in an unwillingness to ambulate or perform deep-breathing exercises.

Literature review.

Previous studies have reported a decrease in nausea following the use of peppermint oil.

Study methodology.

Researchers obtained informed consent from 123 patients for this study; 34 (28%) of them experienced nausea and were offered a nasal inhaler that contained peppermint oil.

Results.

The average nausea rating before the use of peppermint oil was 3.29 (SD, 1.0) on a scale of 0 to 5, with 5 being the greatest nausea. Two minutes later, the average nausea rating was 1.44 (SD, 1.3). Using paired t-tests, these differences were found to be statistically significant (P = 0.000).

Discussion.

The researchers concluded that peppermint oil inhalation is a viable first-line treatment for nausea in postoperative cardiac surgery patients.
Aneuploidy Screening in Pregnancy
Authors: Dashe Jodi S.
Published: June 2016

Prenatal aneuploidy screening has changed dramatically in recent years with increases in the types of chromosomal abnormalities reliably identified and in the proportion of aneuploid fetuses detected. Initially, screening was available only for trisomies 21 and 18 and was offered only to low-risk pregnancies. Improved detection with the quadruple- and first-trimester multiple marker screens led to the option of aneuploidy screening for women 35 years of age and older. Cell-free DNA tests now screen for common autosomal trisomies and sex chromosome aneuploidies. Cell-free DNA screening is particularly effective in older women because of higher positive predictive values and lower false-positive rates. Integrated first- and second-trimester multiple marker tests provide specific risks for trisomies 21, 18, and possibly 13, and may detect an even wider range of aneuploidies. Given current precision in risk assessment, based on maternal age and preferences for screening or diagnostic tests, counseling has become more complex. This review addresses the benefits and limitations of available aneuploidy screening methods along with counseling considerations when offering them.
Baseline Renal Function Tests and Adverse Outcomes in Pregnant Patients With Chronic Hypertension
Authors: Kuper Spencer G. , Tita Alan T. , Youngstrom Mallory L. , Allen Sarah E. , Tang Ying , Biggio Joseph R. , Harper Lorie M.
Published: June 2016

OBJECTIVE:

To examine the relationship between baseline renal function tests in pregnant patients with chronic hypertension and adverse pregnancy outcomes.

METHODS:

This was a retrospective cohort study of women with a singleton pregnancy and chronic hypertension with assessment of renal function (urine protein-to-creatinine ratio and serum creatinine) before 20 weeks of gestation. The primary outcome was severe preeclampsia at less than 34 weeks of gestation. Secondary outcomes were severe preeclampsia at any gestational age, any preeclampsia, preterm birth at less than 35 weeks of gestation, composite perinatal outcome (perinatal death, assisted ventilation, cord pH less than 7, 5-minute Apgar score 3 or less, or neonatal seizures), and small for gestational age. The association between baseline renal function and the primary outcome was assessed with receiver operating characteristic (ROC) curves and objective cutoffs determined. Outcomes were compared between those with values above and below the cutoffs using univariable and multivariable analyses.

RESULTS:

Seven hundred fifty-five pregnant women with chronic hypertension had baseline renal function assessment. The urine protein-to-creatinine ratio and creatinine cutoffs for severe preeclampsia at less than 34 weeks of gestation were 0.12 or greater and 0.75 mg/dL or greater, respectively. The area under the ROC curves for severe preeclampsia at less than 34 weeks of gestation was 0.74 (95% confidence interval [CI] 0.7–0.8) for urine protein-to-creatinine ratio and 0.67 (95% CI 0.6–0.8) for creatinine. A urine protein-to-creatinine ratio 0.12 or greater was associated with an increased risk of developing severe preeclampsia at less than 34 weeks of gestation (16.4% compared with 2.6%, adjusted odds ratio [OR] 7.5, 95% CI 3.9–14.6) as was a creatinine 0.75 mg/dL or greater (15.7% compared with 4.6%, adjusted OR 3.5, 95% CI 1.9–6.3). Severe preeclampsia at less than 34 weeks of gestation occurred in only 1.6% of patients if their baseline tests were below both cutoffs.

CONCLUSION:

Baseline assessment of renal function can be used as a risk stratification tool in pregnant patients with chronic hypertension.
High-Dose Methylprednisolone to Prevent Platelet Decline in Preeclampsia
Authors: Pourrat Olivier , Dorey Marie , Ragot Stéphanie , de Hauteclocque Astrid , Deruelle Philippe , Dreyfus Michel , Pierre Fabrice
Published: June 2016

OBJECTIVE:

To evaluate whether early administration of high-dose methylprednisolone limits the fall of platelets in preeclampsia.

METHODS:

A randomized trial of 180 mg methylprednisolone or placebo administered in divided doses over 36 hours was conducted in women admitted for preeclampsia and platelet counts below 150×109/L in four French academic centers. Patients were not included when platelet counts were below 50×109/L or when immediate delivery was required. The primary study outcome was the proportion of patients with platelet counts above 100×109/L 36 hours after the first dose of study medication. The total sample size needed to detect a 23% difference in the rate of this outcome between groups with a one-tailed α of 0.05 and 90% power was 94 patients.

RESULTS:

Thirty-six patients were randomly assigned to receive methylprednisolone and 34 placebo between October 2007 and May 2011. Platelet counts above 100×109/L at 36 hours after the first dose of study medication were recorded in 30 (83%) in the active group and 29 (85%) in the placebo group (relative risk 0.98, 95% confidence interval 0.80–1.20; P=.82). The only adverse potentially study-related event was hyperglycemia in one woman allocated to methylprednisolone.

CONCLUSION:

In women with preeclampsia and platelet counts under 150×109/L, methylprednisolone was not effective in maintaining platelet counts above 100×109/L.

CLINICAL TRIAL REGISTRATION:

EU Clinical Trials Register, http://clinicaltrialsregister.eu, EudraCT 2006-004881-15-FR.
Reduction in the Cesarean Delivery Rate After Obstetric Care Consensus Guideline Implementation
Authors: Wilson-Leedy Jonas G. , DiSilvestro Alexis J. , Repke John T. , Pauli Jaimey M.
Published: June 2016

OBJECTIVE:

To evaluate the rate of primary cesarean delivery after adopting labor management guidelines.

METHODS:

This is a before–after retrospective cohort study at a single academic center. This center adopted guidelines from the Consensus for the Prevention of the Primary Cesarean Delivery. Nulliparous women attempting vaginal delivery with viable, singleton, vertex fetuses were included. For the primary outcome of cesarean delivery rate among induced or augmented patients, 200 consecutive women managed before guideline adoption were compared with 200 similar patients afterward. Secondary outcomes of overall cesarean delivery rate, maternal morbidity, neonatal outcomes, and labor management practices were analyzed with inclusion of intervening spontaneously laboring women.

RESULTS:

Between September 13, 2013, and September 28, 2014, 275 women preguideline and 292 postguideline were identified to include 200 deliveries after induction or augmentation each. Among women delivering after induction or augmentation, the cesarean delivery rate decreased from 35.5% to 24.5% (odds ratio [OR] 0.59, 95% confidence interval [CI] 0.38–0.91). The overall cesarean delivery rate decreased from 26.9% to 18.8% (adjusted OR 0.59, CI 0.38–0.92). Composite maternal morbidity was reduced (adjusted OR 0.66, CI 0.46–0.94). The frequency of cesarean delivery documenting arrest of dilation at less than 6 cm decreased from 7.1% to 1.1% postguideline (n=182 and 176 preguideline and postguideline, respectively,P=.006) with no change in other indications.

CONCLUSION:

Postguideline, the cesarean delivery rate among nulliparous women attempting vaginal delivery was substantially reduced in association with decreased frequency in the diagnosis of arrest of dilation at less than 6 cm.
Venous Thromboembolism in Minimally Invasive Compared With Open Hysterectomy for Endometrial Cancer
Authors: Barber Emma L. , Gehrig Paola A. , Clarke-Pearson Daniel L.
Published: June 2016

OBJECTIVE:

To evaluate whether minimally invasive surgery for endometrial cancer is independently associated with a decreased odds of venous thromboembolism compared with open surgery.

METHODS:

We performed a secondary analysis cohort study of prospectively collected quality improvement data and examined patients undergoing hysterectomy for endometrial cancer from 2008 to 2013 recorded in the National Surgical Quality Improvement Program database. Patients undergoing minimally invasive (laparoscopic or robotic) surgery were compared with those undergoing open surgery with respect to 30-day postoperative venous thromboembolism. Demographic and procedure variables were examined as potential confounders. Data regarding receipt of perioperative venous thromboembolism prophylaxis were not available. Bivariable tests and logistic regression were used for analysis.

RESULTS:

Of 9,948 patients who underwent hysterectomy for the treatment of endometrial cancer, 61.9% underwent minimally invasive surgery and 38.1% underwent open surgery. Patients undergoing minimally invasive surgery had a lower venous thromboembolism incidence (0.7%, n=47) than patients undergoing open surgery (2.2%, n=80) (P<.001). In a multivariate model adjusting for age, body mass index, race, operative time, Charlson comorbidity score, and surgical complexity, minimally invasive surgery remained associated with decreased odds of venous thromboembolism (adjusted odds ratio 0.36, 95% confidence interval 0.24–0.53) compared with open surgery.

CONCLUSION:

Minimally invasive surgery for the treatment of endometrial cancer is independently associated with decreased odds of venous thromboembolism compared with open surgery.
What Is New in Medical Student and Resident Education?
Authors: Fox Nathan S.
Published: June 2016

This month we focus on current research in medical student and resident education. Dr. Fox discusses four recent publications, which are concluded with a “bottom line” that is the take-home message. The complete reference for each can be found in Box 1 on this page, along with direct links to the abstracts.