bluuebunny/crossref_metadata_2025 huggingface dataset:
Reference Charts of Fetal Biometric Parameters in 31,476 Brazilian Singleton Pregnancies
Authors: Araujo Júnior Edward , Martins Santana Eduardo Félix , Martins Wellington P. , Júnior Julio Elito , Ruano Rodrigo , Pires Claudio Rodrigues , Filho Sebastião Marques Zanforlin
Published: June 2014

Objectives

The purpose of this study was to establish reference charts of fetal biometric parameters measured by 2‐dimensional sonography in a large Brazilian population.

Methods

A cross‐sectional retrospective study was conducted including 31,476 low‐risk singleton pregnancies between 18 and 38 weeks' gestation. The following fetal parameters were measured: biparietal diameter, head circumference, abdominal circumference, femur length, and estimated fetal weight. To assess the correlation between the fetal biometric parameters and gestational age, polynomial regression models were created, with adjustments made by the determination coefficient (R2).

Results

The means ± SDs of the biparietal diameter, head circumference, abdominal circumference, femur length, and estimated fetal weight measurements at 18 and 38 weeks were 4.2 ± 2.34 and 9.1 ± 4.0 cm, 15.3 ± 7.56 and 32.3 ± 11.75 cm, 13.3 ± 10.42 and 33.4 ± 20.06 cm, 2.8 ± 2.17 and 7.2 ± 3.58 cm, and 256.34 ± 34.03 and 3169.55 ± 416.93 g, respectively. Strong correlations were observed between all fetal biometric parameters and gestational age, best represented by second‐degree equations, with R2 values of 0.95, 0.96, 0.95, 0.95, and 0.95 for biparietal diameter, head circumference, abdominal circumference, femur length, and estimated fetal weight.

Conclusions

Fetal biometric parameters were determined for a large Brazilian population, and they may serve as reference values in cases with a high risk of intrauterine growth disorders.
Do Clinical Practitioners Seeking Credentialing for Nuchal Translucency Measurement Demonstrate Compliance With Biosafety Recommendations?
Authors: Bromley Bryann , Spitz Jean , Fuchs Karin , Thornburg Loralei L.
Published: June 2014

Objectives

The purpose of this study was to evaluate compliance with the ALARA (as low as reasonably achievable) principle by practitioners seeking credentialing for nuchal translucency (NT) measurement between 11 and 14 weeks' gestation.

Methods

Nuchal Translucency Quality Review Program credentialing requires quantitative scoring of 5 NT measurements from 5 different fetuses. Images submitted by 100 consecutive practitioners were retrospectively evaluated for the output display standard (ODS). The thermal index (TI) type (bone [TIb] or soft tissue [TIs]) and numeric value of the index were recorded. The TIb was considered the correct index for this study. Compliance with the numeric value was evaluated in several ways. Collectively, a TIb lower than 0.5 was considered optimal, lower than 0.7 compliant, and 1.0 or lower satisfactory.

Results

An ODS was present in at least 1 image submitted by 77 practitioners. The TIb was used exclusively by 15 (19.5%), the TIs by 37 (48.1%), and 25 used a combination of the TIb and TIs. Only 4 of 77 providers (5%) used the correct TI type (TIb) at lower than 0.5 for all submitted images, 5 of 77 (6%) at lower than 0.7, and 9 of 77 (12%) at 1.0 or lower. A TI (TIb or TIs) higher than 1.0 was used by 15 of 77 providers (19.5%). Proficiency in NT measurement and educational background (physician or sonographer) did not influence compliance with ALARA.

Conclusions

Clinicians seeking credentialing in NT do not demonstrate compliance with the recommended use of the TIb in monitoring acoustic output.
Intraobserver Variability in Fibroid Size Measurements
Authors: Moshesh Malana , Peddada Shyamal D. , Cooper Tracy , Baird Donna
Published: June 2014

Objectives

To evaluate intraobserver variability of fibroid sonographic measurements and apply this factor to fibroid growth assessment.

Methods

Study participants were African American women aged 23 to 34 years who had never had a diagnosis of uterine fibroids. All participants underwent transvaginal sonography to screen for the presence of previously undiagnosed fibroids (≥0.5 cm in diameter). The diameters of up to 6 fibroids were measured in 3 perpendicular planes at 3 separate times during the examinations by experienced sonographers. Intraobserver variability as measured by the coefficient of variation (CV) for fibroid diameter and volume was calculated for each fibroid, and factors associated with the CV were assessed by regression models. The impact of variability on growth assessment was determined.

Results

Ninety‐six of 300 women screened were found to have at least 1 fibroid, yielding a total of 174 fibroids for this analysis. The mean CV for the 3 measurements of fibroid maximum diameter was 5.9%. The mean CV for fibroid volume was 12.7%. Fibroid size contributed significantly to intraobserver variability (P = .04), with greater variability for smaller fibroids. Fibroid type (submucosal, intramural, or subserosal) was not important. Fibroids from the same woman tended to have similar measurement variability when assessed for volume but not for maximum diameter. Calculations showed that when following up fibroids, as much as a 20% increase in diameter could be due to measurement error, not “true growth.”

Conclusions

A small fibroid must have a greater change in size than a large fibroid to conclude that it is growing, but even for small fibroids an increase in diameter of greater than 20% is likely to indicate true growth, not measurement variability.
Integrated Cardiopulmonary Sonography
Authors: Wang Xiao-Ting , Liu Da-Wei , Zhang Hong-Min , Chai Wen-Zhao
Published: June 2014

Objectives

Bedside sonography has become a popular method of assessment of critically ill patients with shock and dyspnea. This study evaluated the usefulness of integrated cardiopulmonary sonography for assessment of acute pulmonary edema.

Methods

A total of 128 intensive care unit (ICU) patients with acute pulmonary edema were randomly divided into 2 groups: a sonography group, which received standard treatment as well as cardiopulmonary sonography, and a control group, which received standard treatment only. All patients were treated according to the same therapeutic strategies and underwent chest radiography and central venous catheter placement. Serum myocardial injury marker levels and central venous/arterial blood gas parameters were measured 0, 24, and 72 hours after enrollment. The cumulative fluid infusion volume at 6, 12, 24, and 72 hours, the time to diagnosis of the pulmonary edema etiology by the attending physician, the lengths of ICU and hospital stays, and ICU mortality were recorded.

Results

The sonography group had a shorter time to diagnosis and received a smaller fluid infusion volume than the control group. There were no significant differences in ICU mortality and lengths of ICU and hospital stays between the sonography and control groups. In patients with cardiogenic pulmonary edema, the sonography group had a significantly shorter ICU stay and a faster return to normal myocardial injury marker levels and perfusion parameters than the control group (P < .05).

Conclusions

Integrated cardiopulmonary sonography resulted in faster and better‐informed clinical decision making, shortened the time to diagnosis of the pulmonary edema etiology, and decreased fluid use. However, the impact of this examination on prognoses requires further study. We propose that integrated cardiopulmonary sonography may be a useful bedside tool for treatment of ICU patients with acute pulmonary edema.
Sonographic Evaluation of Knee Cartilage Defects Implanted With Preconditioned Scaffolds
Authors: Ghorayeb Sleiman R. , Levin Adam , Ast Michael , Schwartz John A. , Grande Daniel A.
Published: June 2014

Objectives

The purpose of this study was to develop a novel method for creating an acellular bioactive scaffold, to prove its efficacy in vivo and in vitro for the augmentation of biological repair, and to confirm that sonographic microscopy is a viable modality for monitoring the healing process of osteochondral defects implanted with preconditioned bioactive scaffolds.

Methods

Rabbit marrow stromal cells were retrovirally transduced with either bone morphogenetic protein 7 (BMP‐7) or insulinlike growth factor 1 (IGF‐1) genes, cultured for 9 weeks in nonwoven poly‐L‐lactic acid scaffolds, and then frozen and lyophilized. The knees were evaluated at 3, 6, and 12 weeks after surgery using 20‐MHz ultrasound and then prepared for routine histologic analysis. B‐scans of the extracellular matrix defects were compared to histologic results.

Results

Control defects showed a void or a mixture of fibrocartilage tissue. Both types of scaffolds resulted in a higher percentage (both P< .001) of primarily hyaline cartilage tissue with intact articular surfaces. The osteochondral defects were clearly observed in each sonographic signature. There were no differences between images of scaffolds treated with IGF‐1 or BMP‐7. Extracellular matrix regrowth was found to closely parallel (R2 = 0.968; P < .003) the histologic images. A 3‐mm defect depth and a 2.5‐mm scaffold thickness were measured on the sonograms, comparing well to actual dimensions.

Conclusions

There was a gradual increase in healing bordering the defects for the 3‐, 6‐, and 12‐week samples. Also, we have shown that sonography can aid in monitoring implantation of preconditioned scaffolds in osteochondral defects and thus assessing the healing process and cartilage/bone quality.
Hair Morphology in Androgenetic Alopecia
Authors: Wortsman Ximena , Guerrero Robinson , Wortsman Jacobo
Published: June 2014

Objectives

To assess hair morphology in androgenetic alopecia on sonography and electron microscopy.

Methods

A prospective study was performed in 33 patients with androgenetic alopecia and 10 unaffected control participants. In vivo sonography of the hair follicles of the scalp and in vitro sonography and electron microscopy of the hair shafts were performed according to a standardized protocol that included analysis of the right frontal and occipital regions. The upper frequency limit of the ultrasound probes ranged between 15 and 18 MHz.

Results

Scalp hair follicles and hair shafts were recognizable on sonography in all cases. Hair follicles in alopecia cases had significantly lower depths (P < .05). The hair shafts in alopecia also had a different distribution of their laminar pattern on in vitro sonography, with a greater presence of mixed (trilaminar and bilaminar) and solely bilaminar tracts in comparison with the controls (mostly trilaminar). On electron microscopy, the alopecia hair tracts showed irregularities and commonly a “melted candle” appearance of the cuticle.

Conclusions

Sonography and electron microscopy uncover distinct abnormalities in the morphology of hair in androgenetic alopecia, which may potentially support the diagnosis and management of this common condition.
Quantitative Ultrasound Measurements of the Calcaneus and Hand Phalanges in Elderly Spanish Men
Authors: Lavado-Garcia Jesus M. , Moran Jose M. , Roncero-Martin Raul , Calderon-Garcia Julian F. , Pedrera-Canal Maria , Rodriguez-Dominguez Trinidad , Fernandez-Fernandez Pilar , Pedrera-Zamorano Juan D.
Published: June 2014

Objectives

The aims of this pilot study were to describe quantitative ultrasound (US) measurements and peripheral bone mineral density (BMD) of the hand phalanges on dual‐energy x‐ray absorptiometry and to examine the correlations between them in elderly Spanish men.

Methods

We studied 199 healthy men (mean age ± SD, 73.31 ± 5.10 years). The participants were not taking any medications, and they reported no diseases, including diseases that are associated with abnormalities in mineral metabolism. Phalangeal and calcaneal quantitative US measurements and phalangeal BMD measurements were performed in all participants.

Results

A bivariate correlation analysis showed no association between quantitative US assessments at the phalanges or the calcaneus (P = .409). After adjustment for potential confounders, the correlation between phalangeal BMD and phalangeal quantitative US measurements was r = 0.417 (P < .0001), and the correlation for calcaneal quantitative US was r = 0.26 (P = .001). Further adjustment by percentage of body fat increased quantitative US correlations with phalangeal BMD: r = 0.450 (P < .0001) at the phalanges; r = 0.291 (P = .001) at the calcaneus.

Conclusions

There is a small correlation between quantitative US measurements at the calcaneus and phalangeal BMD that increases to a moderate level with quantitative US measurements at the phalanges in elderly Spanish men.
Prevalence of adverse effects among students taking technique classes: A retrospective study
Authors: Kizhakkeveettil Anupama , Sikorski David , Tobias Gene , Korgan Christos
Published: June 2014

Objective

The main objective of this study was to determine characteristics of injuries experienced by students while learning chiropractic procedures in the classroom.

Methods

Injury was defined as any physical adverse effect such as pain, stiffness, headache, and muscle spasm. Survey questions included age, sex, role, anatomical areas of injury, adjustive technique utilized, types of injury, treatment (if any), and recovery time. The survey was administered among the students in the 5th, 6th, and 8th trimesters of our doctor of chiropractic program. Only students who had completed one or more chiropractic procedures courses at the institution were asked to participate in the study.

Results

Female recipients had a higher prevalence of adverse effects as the recipient of the adjustment than did male recipients. The most common site for injury overall was the lower back. The relationship between recipient role and sacroiliac joint injury and the relationship between adjustor role and wrist/hand injury were statistically significant. Students were more likely to be injured in the beginning of their technique education.

Conclusion

This study suggests that students in technique courses learning adjustive procedures experience minor adverse physical effects related to the physical skills being learned. Strategies for prevention need to be considered.
Catchments as simple dynamical systems: A case study on methods and data requirements for parameter identification
Authors: Melsen L. A. , Teuling A. J. , van Berkum S. W. , Torfs P. J. J. F. , Uijlenhoet R.
Published: June 2014

In many rainfall‐runoff models, at least some calibration of model parameters has to take place. Especially for ungauged or poorly gauged basins this can be problematic, because there is little or no data available for calibration. A possible solution to overcome the problems caused by data scarcity is to set up a measurement campaign for a limited time period. In this study, we determine the minimum amount of data required to determine robust parameter values for a simple model with two parameters. The model is constructed such that the parameters can be determined not only with automatic calibration, but also by recession analysis and a priori from Boussinesq theory. The model has been applied to a research catchment in Switzerland. For automatic calibration and recession analysis, one season (5 months) is found to be sufficient to give robust parameters for simulation of high flows over the full observation period. For automatic calibration, this should be the season with the highest precipitation, for recession analysis the season with least evapotranspiration. The Boussinesq equation is able to give good parameter estimates for modeling high flows, but detailed in situ knowledge of the catchment is required. Automatic calibration outperforms recession analysis and Boussinesq theory by far when it comes to parameter estimation with a focus on prediction of low flows. It was shown that a single set of parameters cannot simultaneously describe high and low flows with a reasonable accuracy, suggesting that more than two parameters are needed to characterize subsurface properties.
Coping with model error in variational data assimilation using optimal mass transport
Authors: Ning Lipeng , Carli Francesca P. , Ebtehaj Ardeshir Mohammad , Foufoula‐Georgiou Efi , Georgiou Tryphon T.
Published: June 2014

Classical variational data assimilation methods address the problem of optimally combining model predictions with observations in the presence of zero‐mean Gaussian random errors. However, in many natural systems, uncertainty in model structure and/or model parameters often results in systematic errors or biases. Prior knowledge about such systematic model error for parametric removal is not always feasible in practice, limiting the efficient use of observations for improved prediction. The main contribution of this work is to advocate the relevance of transportation metrics for quantifying nonrandom model error in variational data assimilation for nonnegative natural states and fluxes. Transportation metrics (also known as Wasserstein metrics) originate in the theory of Optimal Mass Transport (OMT) and provide a nonparametric way to compare distributions which is natural in the sense that it penalizes mismatch in the values and relative position of “masses” in the two distributions. We demonstrate the promise of the proposed methodology using 1‐D and 2‐D advection‐diffusion dynamics with systematic error in the velocity and diffusivity parameters. Moreover, we combine this methodology with additional regularization functionals, such as the
‐norm of the state in a properly chosen domain, to incorporate both model error and potential prior information in the presence of sparsity or sharp fronts in the underlying state of interest.
Every Vote Counts: Final Slate for AGU Elections This Fall
Authors: McPhaden Mike , Enderlein Cheryl
Published: June 2014

Voting is a right of membership, and your vote is important!
Recent increases in extreme temperature occurrence over land
Authors: Weaver Scott J. , Kumar Arun , Chen Mingyue
Published: June 2014

Recently observed global and U.S. temperature increases are probed from the perspective of several hundred climate realizations afforded by the availability of reforecast climate model runs from the NCEP Climate Forecast System Version 2. The large number of seasonal realizations with the observed time‐varying CO2 affords a unique opportunity to explore the role of greenhouse gas changes on 3 month seasonal mean temperature increases, and specifically, whether they are the result of a shift in the mean temperature distribution or an increase in its variability. It is found that significant positive shifts in the temperature probability density function (PDF) occur primarily as the result of the time‐varying CO2 included in the historical model runs, although a contribution from natural climate variability modes cannot be categorically excluded. The temperature PDF comparison further indicates that the increasing global and U.S. temperatures over the last 30 years are predominantly the result of shifts in the mean temperature distribution and not increasing temperature variability. As such, the likelihood of increases in the occurrence of warm temperature extremes will likely continue to increase worldwide, leading to significant impacts on many socioeconomic sectors such as agriculture and public health.
Seasonal variations in the South Atlantic Meridional Overturning Circulation from observations and numerical models
Authors: Dong Shenfu , Baringer Molly O. , Goni Gustavo J. , Meinen Christopher S. , Garzoli Silvia L.
Published: June 2014

Monthly climatologies of temperature and salinity from observations and numerical models are used to estimate the Atlantic Meridional Overturning Circulation (AMOC) at 34°S. Observational estimates suggest that the geostrophic transport plays an equal role to the Ekman transport in the AMOC seasonal variations at this latitude, whereas in the models, the Ekman transport controls the AMOC seasonality. The seasonality of the geostrophic transport from observations is largely controlled by the seasonal density variations at the western boundary, but in the models, the eastern boundary dominates. The observed density seasonality at the western boundary is linked to the intensity of the Malvinas Current, which is poorly reproduced in the models. The results indicate that the weak seasonal cycle in the model geostrophic transport can primarily be attributed to excessively strong baroclinicity below the surface mixed layer, whereas the observations show a strong vertical coherence in the velocity down to 1200 m.
Return periods of global climate fluctuations and the pause
Authors: Lovejoy S.
Published: June 2014

An approach complementary to General Circulation Models (GCMs), using the anthropogenic CO2 radiative forcing as a linear surrogate for all anthropogenic forcings [Lovejoy, ], was recently developed for quantifying human impacts. Using preindustrial multiproxy series and scaling arguments, the probabilities of natural fluctuations at time lags up to 125 years were determined. The hypothesis that the industrial epoch warming was a giant natural fluctuation was rejected with 99.9% confidence. In this paper, this method is extended to the determination of event return times. Over the period 1880–2013, the largest 32 year event is expected to be 0.47 K, effectively explaining the postwar cooling (amplitude 0.42–0.47 K). Similarly, the “pause” since 1998 (0.28–0.37 K) has a return period of 20–50 years (not so unusual). It is nearly cancelled by the pre‐pause warming event (1992–1998, return period 30–40 years); the pause is no more than natural variability.
Coseismic velocity change associated with the 2011 Van earthquake (M7.1): Crustal response to a major event
Authors: Acarel Diğdem , Bulut Fatih , Bohnhoff Marco , Kartal Recai
Published: June 2014

Monitoring coseismic velocity changes is a major challenge, since the Earth crust has to be uniformly sampled at preseismic, coseismic, and postseismic stages using repeating active or natural sources. Here we investigate the crustal response to the 2011 Van/Turkey earthquake using ambient noise, which provides the best possible temporal resolution. Combined recordings from the nearest five broadband stations are analyzed for a time period of 6 months framing the main shock. We observe a coseismic velocity decrease of up to 0.76% in the vicinity of the main shock in the frequency range of 0.05–0.3 Hz. The velocity drop is largest at close proximity to the earthquake hypocenter and decreases systematically with distance. We also find a correlation between coseismic velocity decrease and the amount of coseismic slip on the rupture plane. The observed velocity drop shows the drastic response of the brittle crust in response to a major earthquake.
A physical mechanism of the precipitation dipole in the western United States based on PDO‐storm track relationship
Authors: Sung Mi‐Kyung , An Soon‐Il , Kim Baek‐Min , Woo Sung‐Ho
Published: June 2014

It is known that the western United States (US) precipitation displays a north‐south contrast, i.e., the so‐called “precipitation dipole,” during El Niño and La Niña winters. Furthermore, the Pacific Decadal Oscillation (PDO) has been known to modulate this precipitation dipole. However, the underlying physical mechanism regulating this modulation is not well understood. This study revisits previous studies and suggests a physical mechanism of precipitation dipole modulation based on the PDO‐storm track relationship. We found that both jet stream and storm track tend to move northward (southward) over the North Pacific during negative (positive) PDO winters, contributing to the increase of precipitation over the northwestern (southwestern) US, respectively. This relationship is robust regardless of El Niño‐Southern Oscillation (ENSO), possibly facilitating modulation of the precipitation dipole. Moreover, changes in oceanic baroclinicity associated with the PDO phase are suggested to be responsible for anchorage of storm tracks over the North Pacific.
Model of blue jet formation and propagation in the nonuniform atmosphere
Authors: Milikh G. M. , Shneider M. N. , Mokrov M. S.
Published: June 2014

About two decades ago, researchers discovered upward propagating flashes of light originating above thunderstorms. Due to their distinctive, principally blue color, they were named “blue jets” (BJ). The broadly accepted production mechanism of a BJ is through a lightning leader which rises through the nonuniform atmosphere. Specifically, the formation of the initial lightning leader is thought to be governed by the contraction of the current of a streamer flash into a small radius channel. This paper presents results of simulations of the current contraction in the air as a function of both the pressure and convective heat removal time. We have shown that transitions to the contracted state occur in a hysteresis mode that allows both contracted and diffusive states to coexist. We have obtained the critical current for this phase transition and studied the formation and propagation of BJs in the atmosphere through a combination of quantitative models and existing observations of BJs that combine optical images with the data of the electric current carried by the jets.
Solid‐Phase Microextraction and its Application to Natural Products
Authors: Mottaleb M. Abdul , Meziani Mohammed J. , Islam M. Rafiq
Published: June 2014

Solid‐phase microextraction (SPME) is a simple, fast, and efficient sample preparation technique that eliminates the need for solvents and integrates sampling, isolation, and enrichment in one step. Fibers or capillary tubes coated with an appropriate stationary phase are key players in the process. By controlling the polarity and thickness of the coating on fibers or tubes, sampling time, and other extraction parameters, an analyst can achieve very reliable, accurate, and highly quantifiable robust results at subfemtogram level, for gaseous to macromolecular target solutes, with a shorter analysis time compared to conventional extraction methods. This solvent‐free technique requires small samples, saves sample preparation time as well as solvent purchase and disposal costs. Moreover, it is environmental friendly and poses low health hazard risk to the laboratory associates. Today,SPMEhas been integrated to gas chromatography (GC), gas chromatography–mass spectrometry (GC–MS), high performance liquid chromatography (HPLC or LC), LC–MS, or capillary electrophoresis (CE) for analysis of complex mixtures of samples that include environmental, chemical, biochemical, biological, pharmaceuticals, clinical, biomedical, natural products, food abstracts, plant extracts, and organic compounds in media containing nanoparticles.
High Pressure Liquid Chromatography and Ultra‐high Pressure Liquid Chromatography of Plants: Basic Concepts
Authors: Meyer Veronika R.
Published: June 2014

High‐performance liquid chromatography (HPLC) is an essential method in plant analysis. Although it is primarily a separation method, it offers also the possibility of on‐line quantitative analysis during the separation. It can be used for both, the investigation of classes of compounds as well as of individual substances. HPLC is an instrumental method of great flexibility with regard to the separation conditions and to the detection principle. In any case, high pressure is needed; conventional HPLC acts up to about 350 bar. As the available pressure limits the speed of analysis and its separation power, the more recent technology of ultra high‐performance liquid chromatography (UHPLC) works at pressures up to 1000 bar. It allows very fast analyses or high peak capacity (i.e., the number of resolved compounds) or a combination of both demands. The separation environment can be aqueous, for example, in reversed‐phase or ion‐exchange HPLC, or nonpolar with organic solvents in adsorption chromatography, thus allowing a great choice of investigative principles.
Liquid Chromatography and Liquid Chromatograpy‐Mass Spectrometry of Plants: Techniques and Applications
Authors: Arens Nadja , Doell Stefanie , Mock Hans‐Peter
Published: June 2014

Technical advances in LC–MS hardware instrumentation and in data analysis software tools have enabled the routine implementation of comprehensive metabolite studies in many biological laboratories. In this chapter, we describe the current types of MS instruments and corresponding applications. LC–MS systems can be coupled to UV or fluorescence detectors and even spatial resolution of metabolic distribution (MALDI‐imaging) is feasible to gain valuable additional information.

LC–MS applications usually divide into targeted or untargeted approaches, whereby the general aims are either to quantify a known substance or to analyze and compare metabolite profiles of two conditions to identify potential biomarkers. For tentative annotation of unknown compounds, LC–MS/MS analysis are conducted.

An incessantly growing number of software tools have been developed to handle the challenge of extracting biologically valuable information from LC–MS analysis, which generates enormous amounts of data. Furthermore, various databases have been set up to facilitate annotation of compounds of interest.
Strategies for the Analysis of Plant Lipids
Authors: Guschina Irina A. , Harwood John L.
Published: June 2014

Plant lipids are characterized by a number of features unexpected by scientists who study animal or bacterial systems. Photosynthetic tissues contain high amounts of glycosylglycerides while the surfaces are covered in cutin and suberin. The acyl composition is highly unsaturated. Lipid extraction of plants needs special precautions as does general handling of the extracts. In general, complex lipids are best analyzed by a combination of thin‐layer and gas–liquid chromatography. Surface layers need particular methods. For identification, combinations of techniques are required. Recent advances in mass spectrometry allow detailed examination of complex lipid mixtures, lipidomics, and tissue localization of individual classes. Other physical techniques (such as infrared spectroscopy and nuclear magnetic resonance) have particular applications.

This chapter describes the most useful methods currently in use including the use of isotopes to study metabolism. Precautions for nonexperts are mentioned as well as prospects for useful future developments.
Plant Steroids: Occurrence, Biological Significance and their Analysis
Authors: B. Gunaherath G. M. Kamal , Gunatilaka A. A. Leslie
Published: June 2014

Plant steroids constitute a diverse group of natural products. Biosynthetically, they are derived from
S
‐squalene‐2,3‐epoxide via acetate‐mevalonate pathway. Among the plant steroids, phytosterols are ubiquitous in the plant kingdom. It is significant that some phytosterols have been reported to possess hypocholesterolemic activity. Withanolides are a large group of steroidal lactones with various biological activities. Brassinosteroids are a small group of plant steroids exhibiting plant growth hormonal activity. Phytoecdysteroids are polyhydroxylated plant steroids, many of which are known to exhibit anabolic effects with no undesirable side effects. Steroidal alkaloids are nitrogen‐containing plant steroids with an array of biological activities. It is noteworthy that trace amounts of cholesterol and mammalian steroidal hormones including progesterone have been detected in some plants. Analyses of plant steroids mainly utilize chromatographic methods such as thin‐layer chromatography (
TLC
), high performance liquid chromatography (
HPLC
), ultra high performance liquid chromatography (
UHPLC
), and gas liquid chromatography (
GLC
), while photodiode array (
PDA
), evaporative light scattering (
ELS
), and fluorescence (
FL
) detectors and mass spectrometry (
MS
) are commonly used for their detection, quantification, and identification. Some less common techniques employed for the analyses of plant steroids are immunoassays and biological assays.
Plant Proteomics
Authors: Yang Liming , Xu Haibin , Chen Shilin
Published: June 2014

With the increase in the completion of the genome sequence of plant organisms, more attention has been focused on understanding the functions of genes on a genome‐wide scale, not only the exact time and location of gene expression, but also which proteins and under what conditions they express in certain cells, tissues, or organs. While the transcriptomic analysis can only provide us the spatial and temporal specificities or regulatory network relationships of gene expressions, proteome analysis can illustrate the post‐translational modifications of proteins, subcellular localizations, protein–protein interactions, and protein conformations. This chapter focuses on the background and concept of proteomics and the principal research techniques of plant proteomics. These techniques are primarily divided into (i) gel‐based proteomics, (ii) mass spectrometry‐based proteomics, and (iii) chip‐based proteomics. Two‐dimensional electrophoresis (2‐DE) and isobaric tags for relative and absolute quantitation (iTRAQ), which are the two most commonly used methods with the highest resolution in high throughput plant proteomics, are described in details. Finally, opportunities and current challenges to the development of plant proteomic research techniques are discussed.
Gold‐Catalyzed Addition ofHXto Alkynes
Authors: Genin Emilie , Michelet Veronique
Published: June 2014

Among the myriad of organic transformations that have been developed in the area of gold catalysis, the addition of HX to alkynes has been a field of intense investigation. This chapter presents the main and recent contributions in the field of gold‐catalyzed nucleophilic addition of HX to alkynes. The presentation includes the addition ofO‐nucleophiles (including water, alcohols and carboxylic acids), ofN‐nucleophiles and other heteroatom nucleophiles (including thiols and halogens) to alkynes. The historical background for inter‐ and intramolecular additions, the domino processes and the applications to natural products synthesis are highlighted.
[18O]‐Peroxides: Synthesis and Biological Applications
Authors: Mascio Paolo Di , Miyamoto Sayuri , Medeiros Marisa H. G. , Martinez Glaucia R. , Cadet Jean
Published: June 2014

The peroxidation reactions of the main cellular targets including nucleic acids, proteins and unsaturated lipids have received major attention during the last two decades. This was particularly the case for the hydroperoxides generated by1O2, one of the main reactive oxygen species that usually oxidizes biomolecules in a more specific way than either •OH or one‐electron oxidants. Most of the endoperoxides and hydroperoxides produced by 1O2 have been shown to be unstable and therefore their identification is often difficult. The use of [18O]‐labeled1O2released from thermolabile endoperoxides in association with HPLC‐ESI‐MS/MS analysis provides a highly suitable way to gain relevant mechanistic insights into the formation and the decomposition pathways of initially generated peroxidic compounds. The possibility of cell penetration afforded by suitable naphthalene endoperoxides has also been exploited for investigating the reaction of1O2with DNA for accrediting the mechanism of oxidation of guanine in the nucleus and providing an elegant approach for assessing the validity of DNA isolation methods used in the measurement of 8‐oxo‐7,8‐dihydroguanine, an ubiquitous oxidation product. Further developments are expected both in mechanistic studies and applications in cells using [18O]‐labeled1O2generators.
Health Services, User Participation in
Authors: Martin Graham P.
Published: June 2014

User participation is the collective involvement of service users (often defined inclusively to include wider groups such as carers and potential patients) in the planning, purchasing, management, delivery, or evaluation of health care services. This entry covers the rationales behind user participation, the processes by which it is put into practice, and the challenges it faces in its operation.
Directing Valvular Interstitial Cell Myofibroblast‐Like Differentiation in a Hybrid Hydrogel Platform
Authors: Hjortnaes Jesper , Camci‐Unal Gulden , Hutcheson Joshua D. , Jung Sung Mi , Schoen Frederick J. , Kluin Jolanda , Aikawa Elena , Khademhosseini Ali
Published: June 2014

Three dimensional (3D) hydrogel platforms are powerful tools, providing controllable, physiologically relevant microenvironments that could aid in understanding how various environmental factors direct valvular interstitial cell (VIC) phenotype. Continuous activation of VICs and their transformation from quiescent fibroblast to activated myofibroblast phenotype is considered to be an initiating event in the onset of valve disease. However, the relative contribution VIC phenotypes is poorly understood since most 2D culture systems lead to spontaneous VIC myofibroblastic activation. Here, a hydrogel platform composed of photocrosslinkable versions of native valvular extracellular matrix components—methacrylated hyaluronic acid (HAMA) and methacrylated gelatin (GelMA)—is proposed as a 3D culture system to study VIC phenotypic changes. These results show that VIC myofibroblast‐like differentiation occurs spontaneously in mechanically soft GelMA hydrogels. Conversely, differentiation of VICs encapsulated in HAMA‐GelMA hybrid hydrogels, does not occur spontaneously and requires exogenous delivery of TGFβ1, indicating that hybrid hydrogels can be used to study cytokine‐dependent transition of VICs. This study demonstrates that a hybrid hydrogel platform can be used to maintain a quiescent VIC phenotype and study the effect of environmental cues on VIC activation, which will aid in understanding pathobiology of valvular disease.
High‐Performance Plasmonic Sensors Based on Two‐Dimensional Ag Nanowell Crystals
Authors: Ye Shunsheng , Zhang Xuemin , Chang Lingxia , Wang Tieqiang , Li Zibo , Zhang Junhu , Yang Bai
Published: June 2014

A high‐performance plasmonic biosensor based on two‐dimensional (2D) Ag nanowell crystals is rationally designed and fabricated by colloidal litho­graphy. The crystals act as 2D metallic gratings that directly couple incident photons to surface plasmon polaritons (SPPs). The nanowell sizes are properly tuned to enable coupling between the SPPs and Raleigh anomalies, which proves to greatly contribute to sharp reflectance dips. Other geometric parameters including the nanowell depth and the lattice constant are respectively adjusted to optimize the lineshape and sensitivity. These inferences and experimental results are verified by finite‐difference time‐domain (FDTD) calculations. In this study, the fabricated crystal with 670 nm lattice constant, 483 nm nanowell size, and 40 nm nanowell depth possesses the highest refractive index sensitivity (RIS) (623.7 nm RIU−1), the maximum figure of merit (FOM) (55.2 RIU−1), and a very high value of full height/full width at half‐maximum (FH/FWHM) (28.3 ×10−3 nm−1). As a proof‐of‐concept, we adopt the well‐studied antigen‐antibody couple as a model system to illustrate the potential of the nanowell crystal in a quantitative analytical bioassay. The excellent sensing performance, together with the compact structure and the simple read‐out apparatus, suggest that the 2D Ag nanowell crystal is an excellent candidate for a label‐free biosensing platform.
The First Allylation of Esters by an Allylsilane: One‐Pot Domino Synthesis of Triallylmethane Derivatives
Authors: Bandi Chenna Kesava Reddy , Belostotskii Anatoly , Hassner Alfred
Published: June 2014

We report the first successful allylation of aromatic esters by allyltrimethylsilane. The reaction is mediated by 0.3–1.0 equiv. of titanium tetrachloride (TiCl4) at room temperature and leads in a multi‐step, one‐pot reaction to quaternary triallylmethane derivatives 5. The most efficient ester possessed two ortho‐methoxy substituents on the phenol ring. Molecular modelling revealed the ability of this compound to form a bidentate titanium complex, thus improving the steric accessibility of the ester carbonyl to nucleophilic attack.

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Association of the T102C polymorphism in the HTR2A gene with major depressive disorder, bipolar disorder, and schizophrenia
Authors: Tan Jinjing , Chen Shan , Su Li , Long Jianxiong , Xie Juanjuan , Shen Tingting , Jiang Juan , Gu Lian
Published: June 2014

A number of studies have assessed a relationship between the T102C polymorphism in the HTR2A gene with an increased risk of major depressive disorder (MDD), bipolar disorder (BPD), and schizophrenia (SCZ). However, the results have been inconsistent. Hence, we performed this study to further evaluate potential associations between the T102C polymorphism and MDD, BPD, and SCZ. The strength of separate associations between the T102C polymorphism and the risk of MDD, BPD, or SCZ was measured by ORs and 95% confidence intervals (CIs) in six genetic models. Cochran's chi‐square‐based Q‐statistic and I2 were used to evaluate the heterogeneity between studies. The funnel plot and the Egger's test were used to assess the publication bias. Cumulative meta‐analysis was also performed to evaluate the trend in OR over time. No significant association was found in the overall analysis of MDD, BPD and SCZ with a sample size of 17,178 cases and 20,855 control subjects. In a further analysis by ethnicity, the OR and 95% CIs indicated the T102C polymorphism was not associated with MDD, BPD, or SCZ in Caucasian, Asian or Chinese populations. No publication bias was observed in the meta‐analysis, and the cumulative analyses indicated the robust stability of the results. Thus, the results of our study indicate that the T102C polymorphism is not associates with increased susceptibility to MDD, BPD, and SCZ. © 2014 Wiley Periodicals, Inc.
Trifluormethylierung von Alkenen unter gleichzeitiger Einführung weiterer funktioneller Gruppen
Authors: Egami Hiromichi , Sodeoka Mikiko
Published: June 2014

Die Trifluormethylgruppe ist Bestandteil vieler synthetischer bioaktiver Verbindungen, und die Difunktionalisierung von CC‐Bindung wurde als wirksame Strategie zum Aufbau von Verbindungen mit verschiedenen Funktionalitäten intensiv erforscht. Folgerichtig ist die difunktionalisierende Trifluormethylierung von Alkenen auf wachsendes Interesse gestoßen, da die Produkte potenzielle Bausteine für bioaktive Moleküle darstellen. Dieser Aufsatz stellt neueste Fortschritte bei der Trifluormethylierung von Alkenen unter gleichzeitiger Einführung weiterer funktioneller Gruppen vor.
Strategien für die Synthese funktioneller Naphthalindiimide
Authors: Suraru Sabin‐Lucian , Würthner Frank
Published: June 2014

Naphthalindiimide, die lange im Schatten ihrer größeren homologen Perylendiimide standen, gehören gegenwärtig zu einer der am meisten untersuchten organischen Substanzklassen. Zu verdanken ist dies vornehmlich den präparativen Vorarbeiten zur Kernfunktionalisierung zu Beginn des letzten Jahrzehnts, welche die vielfältigen strukturellen Modifizierungen des Naphthalindiimid‐Grundkörpers ermöglichten. Mit relativ geringem Syntheseaufwand sind Verbindungen mit stark veränderten optischen und elektrochemischen Eigenschaften zugänglich, die je nach Funktionalisierung leicht und effektiv eingestellt werden können. Dies hat verschiedene interessante Anwendungen zur Folge. So macht der elektronenarme Charakter der Verbindungen sie besonders auf dem Gebiet der organischen Elektronik als luftstabile n‐Halbleiter höchst bedeutsam, während die durch Kernsubstituenten über den gesamten sichtbaren Spektralbereich einstellbaren Absorptionsbanden interessante Photosysteme und Photovoltaikanwendungen möglich gemacht haben. Dieser Aufsatz gibt einen Überblick über die verschiedenen Möglichkeiten zur Kernfunktionalisierung und die vornehmlich in den letzten fünf Jahren entwickelten Synthesestrategien zur Kernexpansion des Naphthalindiimids.
Elektrochemisch erzeugte Gradienten
Authors: Krabbenborg Sven O. , Huskens Jurriaan
Published: June 2014

Gegenstand dieses Aufsatz ist die aktuellen Entwicklung auf dem Gebiet von elektrochemisch erzeugten Gradienten. Eine graduelle Änderung von Merkmalen, die das Charakteristikum von Gradienten ist, hat für Technologie und Biologie eine große Bedeutung, wie das “directional wetting” bzw. die Chemotaxis zeigen. Elektrochemische Techniken bieten viele Vorteile, darunter die Erzeugung von dynamischen Lösungs‐ und Oberflächengradienten, die Integration von elektronischen Bauteilen und die Automatisierung. Hier werden neue Methoden vorgestellt, von rein elektrochemischen Techniken bis hin zur Kombination von Elektrochemie mit anderen Verfahren. Elektrochemisch erzeugte Gradienten werden in biologischem und technologischem Kontext eingesetzt. Beispiele sind Hochdurchsatzscreening und ‐galvanisierung sowie elektronische Bauelemente. Besonders vielversprechend sind Entwicklungen, die sich mit der Untersuchung und gezielten Beeinflussung von dynamischen Phänomenen befassen, etwa mit der gerichteten Bewegung von Molekülen, Tröpfchen und Zellen.
Organokatalytische asymmetrische Hydrolyse von Epoxiden
Authors: Monaco Mattia Riccardo , Prévost Sébastien , List Benjamin
Published: June 2014

Die hydrolytische Ringöffnung von Epoxiden ist eine wichtige biosynthetische Umwandlung und wird auch industriell eingesetzt. Wir berichten von der ersten organokatalytischen Variante dieser Reaktion. Hierbei nutzen wir unsere kürzlich entdeckte Aktivierung von Carbonsäuren mit chiralen Phosphorsäuren über Heterodimerbildung. Die Methode ahmt den enzymatischen Mechanismus nach, der ein enzymgebundenes Carboxylatnukleophil aufweist. Eine neu entwickelte Phosphorsäure zeigt hohe Stereokontrolle in der Desymmetrisierung von meso‐Epoxiden. Die Methode ist breit anwendbar auf cyclische, acyclische, aromatische und aliphatische Substrate. Des Weiteren nutzen wir unsere Methode in der ersten hochenantioselektiven anti‐Dihydroxylierung von einfachen Olefinen.
Self‐Assembly of DNA–Oligo(p‐phenylene‐ethynylene) Hybrid Amphiphiles into Surface‐Engineered Vesicles with Enhanced Emission
Authors: Albert Shine K. , Thelu Hari Veera Prasad , Golla Murali , Krishnan Nithiyanandan , Chaudhary Soma , Varghese Reji
Published: June 2014

Surface‐addressable nanostructures of linearly π‐conjugated molecules play a crucial role in the emerging field of nanoelectronics. Herein, by using DNA as the hydrophilic segment, we demonstrate a solid‐phase “click” chemistry approach for the synthesis of a series of DNA–chromophore hybrid amphiphiles and report their reversible self‐assembly into surface‐engineered vesicles with enhanced emission. DNA‐directed surface addressability of the vesicles was demonstrated through the integration of gold nanoparticles onto the surface of the vesicles by sequence‐specific DNA hybridization. This system could be converted to a supramolecular light‐harvesting antenna by integrating suitable FRET acceptors onto the surface of the nanostructures. The general nature of the synthesis, surface addressability, and biocompatibility of the resulting nanostructures offer great promises for nanoelectronics, energy, and biomedical applications.
Die Totalsynthese von (−)‐Nitidasin
Authors: Hog Daniel T. , Huber Florian M. E. , Mayer Peter , Trauner Dirk
Published: June 2014

Nitidasin, ein komplexes Sesterterpenoid mit einem seltenen 5‐8‐6‐5‐Kohlenstoffgerüst, wurde aus dem peruanischen Naturheilmittel “Hercampuri” isoliert und ist ein Vertreter einer kleinen Gruppe von polycyclischen Sesterterpenoiden, die eine trans‐Hydrindaneinheit mit einem Isopropylsubstituenten aufweisen. Als erstes Ergebnis unseres allgemeinen Ansatzes zur Synthese solcher Naturstoffe stellen wir die Totalsynthese der Titelverbindung vor. Die Schlüsselsequenz unserer stereoselektiven und konvergenten Route besteht aus der Addition einer komplexen Alkenyllithiumverbindung an ein trans‐Hydrindanon, einer chemoselektiven Epoxidierung und einer Ringschlussmetathese.