bluuebunny/crossref_metadata_2025_split huggingface dataset:
Noninvasive assessment of intracranial elastance and pressure in spontaneous intracranial hypotension by MRI
Authors: Tsai Yi‐Hsin , Chen Hung‐Chieh , Tung Hsin , Wu Yi‐Ying , Chen Hsian‐Min , Pan Kuan‐Jung , Cheng Da‐Chuan , Chen Jeon‐Hor , Chen Clayton Chi‐Chang , Chai Jyh‐Wen , Shen Wu‐Chung 
Published: February 2018

BackgroundSpontaneous intracranial hypotension (SIH) is often misdiagnosed, and can lead to severe complications. Conventional MR sequences show a limited ability to aid in this diagnosis. MR‐based intracranial pressure (MR‐ICP) may be able to detect changes of intracranial elastance and pressure.PurposeTo determine whether MR‐ICP is able to differentiate SIH patients from normal subjects, improve diagnostic sensitivity, and provide an insight into the pathophysiology.Study TypeProspective.SubjectsTwenty‐eight SIH cases with orthostatic headache and 20 healthy volunteers.Field Strength/SequenceCine phase‐contrast MRI on a 1.5T scanner.AssessmentIntracranial elastance (IE) was derived from the ratio of the peak‐to‐peak cerebrospinal fluid (CSF) pressure gradient (PGcsf‐pp) and intracranial volume change, obtained by summing all flows before each sequential cardiac frame.Statistical TestsStudent's t‐test was used to compare the MR‐ICP indexes and flow parameters between SIH patients and healthy volunteers (P < 0.01).ResultsThe SIH patients with cervical epidural venous dilatation (EVD) had an IE of 0.121 ± 0.027 mmHg/cm/ml, significantly higher than that of the normal volunteers (0.085 ± 0.027 mmHg/cm/ml; P = 0.002). In contradistinction, the EVD‐negative SIH patients, including four with no sign of CSF leaks, had significantly lower IE (0.055 ± 0.012 mmHg/cm/ml) compared with the normal volunteers and the EVD‐positive group (P = 0.001, P < 0.001). The EVD‐negative patients had significantly lower PGcsf‐pp (0.024 ± 0.007 mmHg/cm) compared with the normal volunteers and the EVD‐positive group (0.035 ± 0.011 mmHg/cm, 0.040 ± 0.010 mmHg/cm; P = 0.003, P < 0.001). Additionally, the MRI flow study showed a significant decrease in transcranial inflow and outflow of SIH patients (P < 0.01).Data ConclusionWe found that the MR‐ICP method is potentially more sensitive than morphological MRI in the early diagnosis of SIH. Also, contrary to common belief, our results suggest that an abnormal craniospinal elastance might be the cause of SIH, instead of CSF leak.Level of Evidence: 2Technical Efficacy: Stage 3J. Magn. Reson. Imaging 2018;47:1255–1263.
Simultaneous determination and pharmacokinetics study of four quinones in rat plasma by ultra high performance liquid chromatography with electrospray ionization tandem mass spectrometry after the oral administration of Qianzhi capsules
Authors: Gao Mingjie , Wang Zhibin , Yang Jing , Wang Liqian , Wu Chengcui , Cui Binbin , Yang Chunjuan 
Published: February 2018

AbstractA sensitive, specific, and accurate ultra high‐performance liquid chromatography with electrospray ionization tandem mass spectrometry method was developed and validated for the simultaneous quantification of purpurin, munjistin, mollugin, and alizarin from Qianzhi capsules in rat plasma. Chromatographic separation was performed on an Agilent Eclipse Plus C18 RRHD column with a mobile phase consisting of methanol and 5 mM ammonium acetate/water with gradient elution. The analytes were quantified on a triple quadrupole mass spectrometer, operating in the multiple reaction monitoring mode and switching the electrospray ion source polarity with positive electrospray ionization in a single run. Samples were pretreated by liquid–liquid extraction with cyclohexane. The intra‐ and interday precision and accuracy of the assay were within acceptable ranges. Matrix effects for all of the analytes were between 90.16 and 100.21%. The average recovery ranged from 75.38 to 88.96%. This method was successfully applied to study the pharmacokinetic parameters of the four compounds in rat plasma after oral administration of Qianzhi capsules. Four quinones could be rapidly absorbed into blood (tmax, 0.80–1.93 h) and eliminated relatively slowly (t1/2, 8.07–11.97 h). The results might be helpful for guiding the clinical application of Qianzhi capsules in the future.
A novel sorbent based on carbon nanotube/amino‐functionalized sol–gel for the headspace solid‐phase microextraction of α‐bisabolol from medicinal plant samples using experimental design
Authors: Yarazavi Mina , Noroozian Ebrahim 
Published: February 2018

AbstractA novel sol–gel coating on a stainless‐steel fiber was developed for the first time for the headspace solid‐phase microextraction and determination of α‐bisabolol with gas chromatography and flame ionization detection. The parameters influencing the efficiency of solid‐phase microextraction process, such as extraction time and temperature, pH, and ionic strength, were optimized by the experimental design method. Under optimized conditions, the linear range was between 0.0027 and 100 μg/mL. The relative standard deviations determined at 0.01 and 1.0 μg/mL concentration levels (n = 3), respectively, were as follows: intraday relative standard deviations 3.4 and 3.3%; interday relative standard deviations 5.0 and 4.3%; and fiber‐to‐fiber relative standard deviations 6.0 and 3.5%. The relative recovery values were 90.3 and 101.4% at 0.01 and 1.0 μg/mL spiking levels, respectively. The proposed method was successfully applied to various real samples containing α‐bisabolol.
Evaluation of solid‐phase extraction procedures for the quantitation of venlafaxine in human saliva by high‐performance liquid chromatography
Authors: Dziurkowska Ewelina , Wesolowski Marek 
Published: February 2018

AbstractIn recent years, the use of human saliva for diagnostic purposes has evoked great interest. Thus, the aim of this study was to choose the optimal solid‐phase extraction cartridges and extraction solvents for the quantitation of venlafaxine in saliva. Blank saliva samples spiked with venlafaxine concentrations between 25 and 750 ng/mL were analyzed using five solid‐phase extraction columns (C18, C8, Strata‐X, Strata‐X‐C, and Strata‐X‐AW), washing solvents (deionized water, phosphate buffer at pH 5.5, and their mixtures with methanol), and elution solvents (methanol, acetonitrile, and their mixtures with 25% ammonia). A high‐performance liquid chromatography system was used to quantify venlafaxine in saliva. The results of this study revealed that nine of 25 procedures enabled quantitation of venlafaxine in the tested concentration range. The procedure that used a C18 cartridge, a mixture of methanol and deionized water as the washing solvent, and methanol as the elution solvent was the most effective and allowed quantitation of all venlafaxine concentrations with an acceptable recovery. In contrast, the Strata‐X‐C cartridge could not detect venlafaxine at the lowest concentration (25 ng/mL). The data acquired from the high‐performance liquid chromatography system were confirmed by a multivariate data analysis.
The application of natural landform analogy and geology‐based spoil classification to improve surface stability of elevated spoil landforms in the Bowen Basin, Australia—A review
Authors: Emmerton Bevan , Burgess Jon , Esterle Joan , Erskine Peter , Baumgartl Thomas 
Published: February 2018

AbstractLarge‐scale open cut mining has occurred within the Bowen Basin for over 4 decades, transitioning from shallow mining depths and limited spoil elevation to increased mining depths, prestripping and increasingly elevated mesa‐like landforms.As a result of this evolution, the stabilisation of modern constructed landforms is no longer assured through the establishment of vegetation alone. The selection of resilient fragmental spoil types for the construction of final landform surfaces, and as cladding for stabilising steep erosive batters, is a practical methodology that has the potential to significantly improve rehabilitation outcomes, by increasing surface rock cover, roughness, and infiltration and reducing erodibility. An understanding of the properties and behaviour of individual spoil materials disturbed during mining is required.Relevant information from published literature on the geological origins, lithology, and weathering characteristics of individual strata within the Bowen Basin Coal Measures (and younger overlying weathered strata) has been reviewed, related to natural landforms and applied to the surface stability of major strata types when disturbed by mining.A spoil classification derived from geological characteristics and weathering behaviour of identifiable lithologic components has been reviewed and refined, demonstrating the application of use of geological information.This classification system is a tool for the allocation of spoil types and use of categories that have application in premine feasibility investigations, landform design, and material selection and placement. The logic of classifying materials based on their stability in the natural landscape has wider relevance to other mining areas where elevated landforms of sedimentary material are constructed.
Peat bog and alluvial deposits reveal land degradation during 16th‐ and 17th‐century colonisation of the Western Carpathians (Czech Republic)
Authors: Kapustová Veronika , Pánek Tomáš , Hradecký Jan , Zernitskaya Valentina , Hutchinson Simon M. , Mulková Monika , Sedláček Jan , Bajer Vojtěch 
Published: February 2018

AbstractWallachian (shepherd) colonisation of the upper parts of the Carpathians, the second largest mountain range in Europe, provides a unique opportunity to study human‐induced ecological changes and subsequent sediment mobilisation within slope and fluvial systems. The Wallachians came to the nearly pristine landscape in the Czech part of the Western Carpathians during the 16th to 17th century bringing large‐scale deforestation and grazing to the upper parts of its ridges. Despite the importance of this event, there is a lack of high‐resolution multiproxy reconstructions to help decipher the relative influence of anthropogenic and climate factors on this landscape. Here, we provide an approximately 2.1‐kyr record obtained from a peat bog where, using chronological, sedimentological, and pollen analyses, we were able to differentiate between environmental conditions before, during, and after colonisation. Prior to colonisation, climate deterioration following the onset of Little Ice Age caused changes in forest composition and erosion events (causing a ~ad 0–1500 gap in the record). Abrupt human‐induced deforestation detected in the pollen record, together with the abundant fine‐grained minerogenic content of peat deposits between ad ~1640 and ad 1870, corresponds to increased run‐off and sheet erosion on slopes, enhanced by Little Ice Age climate deterioration. The sedimentary record in alluvial deposits downstream indicates that the colonisation of the mountain slopes in this region not only had a local effect on soil degradation, but it also increased the net aggradation of overbank deposits within valley floors. After reforestation, net aggradation was replaced by river incision into alluvia.
Ants respond more strongly to grazing than changes in shrub cover
Authors: Radnan Gabriella N. , Eldridge David J. 
Published: February 2018

AbstractIncreases in the cover or density of woody plants (encroachment) and overgrazing by European livestock are 2 major drivers of ecosystem structure and function in drylands and are often associated with land degradation. Although the effects of encroachment and overgrazing on vascular plants are relatively well known, little is known about their effects on arthropods such as ants. We examined ant community composition at sites ranging in shrub cover in a wooded dryland in eastern Australia, testing the notion that increasing shrub cover and grazing intensity would alter ant assemblages and functional group composition. We used ants because they are abundant, diverse, and respond to small‐scale environmental changes. Increasing shrub cover had no effect on ant richness, diversity, or evenness but increased the abundance of Subordinate Camponotini. Larger shrubs tended to have greater ant richness, and abundance of Cold Climate Specialists, but fewer Generalized Myrmicinae and Hot Climate Specialists. More intense grazing was associated with greater ant richness, diversity, and evenness; a greater abundance of Hot Climate Specialists and Dominant Dolichoridae; and lower abundance of Subordinate Camponotini. Our study indicates that changes in grazing intensity had stronger effects on ant richness than any increase in shrub cover. The effects of grazing likely resulted from changes in soil surface complexity such as barer ground associated with grazing‐induced degradation.
Early response ofQuercus roburseedlings to soil compaction following germination
Authors: Cambi Martina , Mariotti Barbara , Fabiano Fabio , Maltoni Alberto , Tani Andrea , Foderi Cristiano , Laschi Andrea , Marchi Enrico 
Published: February 2018

AbstractLogging operations using heavy machinery effect changes in soil characteristics due to compaction; such conditions can negatively influence seedling development. In stands managed on the basis of close‐to‐nature silviculture or continuous cover forestry, successful establishment of natural regeneration after logging is important to ensure the proper functioning of a forest ecosystem, to promote soil recovery, and to prevent and mitigate land degradation processes (such as soil erosion, mudflow, waterlogging, and landslides) related to soil compaction and rutting. This work aimed to assess the early response ofQuercus roburseedlings to soil compaction during the first 1.5 months after germination. The study was carried out in a controlled environment using 8 L containers filled with natural alluvial soil. Three levels of soil compaction were applied in a laboratory using a compression‐testing machine placed on the top surface of the soil in the containers. The morphological traits of the seedling shoot and root systems were analysed to compare 3 compaction levels. There were significant differences in seedling traits among the treatments, and they indicated that increasing levels of compaction reduced early seedling growth after emergence. Compaction had a larger impact on the root system, particularly the development at depth (root system depth, and main root length), compared with the shoot system. Our results suggest that compaction affects seedling root system growth following the first growth stages after germination; thus, compaction represents an additional critical factor for seedling establishment, particularly in environments where early growth is crucial for overcoming the dry season.
A Stereolithography‐Based 3D Printed Hybrid Scaffold for In Situ Cartilage Defect Repair
Authors: Aisenbrey Elizabeth A. , Tomaschke Andrew , Kleinjan Eric , Muralidharan Archish , Pascual‐Garrido Cecilia , McLeod Robert R. , Ferguson Virginia L. , Bryant Stephanie J. 
Published: February 2018

AbstractDamage to articular cartilage can over time cause degeneration to the tissue surrounding the injury. To address this problem, scaffolds that prevent degeneration and promote neotissue growth are needed. A new hybrid scaffold that combines a stereolithography‐based 3D printed support structure with an injectable and photopolymerizable hydrogel for delivering cells to treat focal chondral defects is introduced. In this proof of concept study, the ability to a) infill the support structure with an injectable hydrogel precursor solution, b) incorporate cartilage cells during infilling using a degradable hydrogel that promotes neotissue deposition, and c) minimize damage to the surrounding cartilage when the hybrid scaffold is placed in situ in a focal chondral defect in an osteochondral plug that is cultured under mechanical loading is demonstrated. With the ability to independently control the properties of the structure and the injectable hydrogel, this hybrid scaffold approach holds promise for treating chondral defects.
Asymmetric Alkyl Side‐Chain Engineering of Naphthalene Diimide‐Based n‐Type Polymers for Efficient All‐Polymer Solar Cells
Authors: Jia Tao , Li Zhenye , Ying Lei , Jia Jianchao , Fan Baobing , Zhong Wenkai , Pan Feilong , He Penghui , Chen Junwu , Huang Fei , Cao Yong 
Published: February 2018

AbstractThe design and synthesis of three n‐type conjugated polymers based on a naphthalene diimide–thiophene skeleton are presented. The control polymer, PNDI‐2HD, has two identical 2‐hexyldecyl side chains, and the other polymers have different alkyl side chains; PNDI‐EHDT has a 2‐ethylhexyl and a 2‐decyltetradecyl side chain, and PNDI‐BOOD has a 2‐butyloctyl and a 2‐octyldodecyl side chain. These copolymers with different alkyl side chains exhibit higher melting and crystallization temperatures, and stronger aggregation in solution, than the control copolymer PNDI‐2HD that has the same side chain. Polymer solar cells based on the electron‐donating copolymer PTB7‐Th and these novel copolymers exhibit nearly the same open‐circuit voltage of 0.77 V. Devices based on the copolymer PNDI‐BOOD with different side chains have a power‐conversion efficiency of up to 6.89%, which is much higher than the 4.30% obtained with the symmetric PNDI‐2HD. This improvement can be attributed to the improved charge‐carrier mobility and the formation of favorable film morphology. These observations suggest that the molecular design strategy of incorporating different side chains can provide a new and promising approach to developing n‐type conjugated polymers.
Low‐Density Self‐Assembled Poly(N‐Isopropyl Acrylamide) Sponges with Ultrahigh and Extremely Fast Water Uptake and Release
Authors: Jiang Shaohua , Helfricht Nicolas , Papastavrou Georg , Greiner Andreas , Agarwal Seema 
Published: February 2018

AbstractPoly(N‐isopropyl acrylamide) (PNIPAM) hydrogels are well known for their temperature‐dependent water uptake and release. Hence, they are ideal candidates for water management applications. However, efficiency and rate of water uptake and release, respectively, have to be optimized. Here, highly stable 3D PNIPAM sponges that show a sufficiently low density and high specific pore volume, required for maximizing the amount and rate of water absorption‐desorption, are presented. They are prepared by a top‐down approach based on freeze‐drying a dispersion of short crosslinked PNIPAM fibers coated with crosslinked PNIPAM. The sponges have low densities (4.10–21.04 mg cm−3), high porosities >98%, and high specific pore volumes in the range of 47–243 cm3 g−1 depending on the concentration of the dispersions. The sponges absorb high amounts of water (≈7000%) at temperatures below the lower critical solution temperature (LCST) of PNIPAM and can release more than 80% of the absorbed water above the LCST in less than 2 min. Moreover, the water‐swollen sponges are reversibly foldable, can be confined to different shapes, and have compressive elastic modulus below 10 Pa. Hence, these spongy materials are of interest not only for water management but also for biomedical applications, smart textiles, and catalysis.
Effect of load on tribofilms at the contact interface under dry sliding conditions at 500 °C
Authors: Saleem S.S. , Wani M.F. 
Published: February 2018

AbstractThis paper presents a study of the effect of load on the retention of the tribofilms formed at the interface of a dry sliding contact between exhaust valve material, Nimonic alloy (N 80A) and valve‐seat material, ductile cast iron (GGG‐40), at a temperature of 500 °C. The role of tribofilms in influencing friction and wear behaviour at elevated temperature is highlighted. Reciprocating pin‐on‐disc experiments were conducted using a hemispherical shaped pin sliding against a flat disc at 20 Hz oscillating frequency, 2 mm stroke at loads of 20 N to 50 N. Low coefficient of friction, in the range of 0.13 to 0.15, was observed at loads up to 40 N whereas at a load of 50 N, the average coefficient of friction increased to 0.29. Optical and scanning electron micrographs with energy dispersive spectroscopy analysis indicate evidence of formation and retention of well compacted and strongly adhering tribofilms at loads up to 40 N. At 50 N, even though more abrasive wear is seen, initial deterioration and subsequent reforming of the tribofilms with increasing sliding time is observed. Overall, more wear was observed for the valve‐seat material as compared to the valve material. Raman spectroscopy primarily indicates the presence of hematite on the worn surfaces at loads of 20 N to 40 N, whereas magnetite presence is strongest at the highest load of 50 N. Increase in tribofilm hardness was observed with increase in contact load whereas the thickness of the tribofilm was not significantly affected by the contact load.
Nigrostriatal dopamine transporter availability in early Parkinson's disease
Authors: Fazio Patrik , Svenningsson Per , Cselényi Zsolt , Halldin Christer , Farde Lars , Varrone Andrea 
Published: February 2018

ABSTRACTBackground: The imaging of biomarkers for characterization of dopaminergic impairment in Parkinson's disease (PD) is useful for diagnosis, patient stratification, and assessment of treatment outcomes. [18F]FE‐PE2I is an improved imaging tool allowing for detailed mapping of the dopamine transporter protein in the nigro‐striatal system at the level of cell bodies (substantia nigra), axons, and presynaptic terminals (striatum).Objectives: The objective of this study was to compare the dopamine transporter protein loss in the presynaptic terminals to that in the cell bodies and axons in early PD patients using [18F](E)‐N‐(3‐iodoprop‐2‐enyl)‐2b‐carbofluoroethoxy‐3b‐(4′‐methyl‐phenyl) nortropane ([18F]FE‐PE2I) and high‐resolution PET.Methods: A total of 20 early PD patients (15 men/5 women, 62 ± 8 years) and 20 controls (15 men/5 women, 62 ± 7 years) underwent high‐resolution [18F]FE‐PE2I PET. Dopamine transporter protein availability was estimated for the different nigro‐striatal regions and expressed as nondisplaceable binding potential values.Results: When compared with controls, the binding potential values in PD patients were reduced by 36% to 70% in presynaptic terminals and by 30% in cell bodies. Dopamine transporter availability along the tracts was not different between the 2 groups (controls 0.5 ± 0.1 vs PD 0.4 ± 0.1).Conclusions: This is the first study that examines dopamine transporter protein availability in vivo within the entire nigro‐striatal pathway. The results suggest that at early stages of symptomatic PD a greater loss is observed at the level of the axonal terminals when compared with cell bodies and axons of dopaminergic neurons. The findings suggest a relative preservation of cell bodies in early PD, which might be relevant for novel disease‐modifying strategies. © 2018 International Parkinson and Movement Disorder Society
Ataxia‐telangiectasia: A review of movement disorders, clinical features, and genotype correlations
Authors: Levy Ariel , Lang Anthony E. 
Published: February 2018

ABSTRACTAtaxia‐telangiectasia is an autosomal recessive neurodegenerative disorder that was initially thought to present exclusively in childhood. With the discovery of the ATM gene, the phenotypic spectrum of the condition has expanded. This review elaborates the expanded phenomenology, including oculomotor apraxia and immunodeficiency, and estimates the presence of each movement disorder feature from previously reported literature. Initial manifestations of Ataxia‐telangiectasia include cerebellar symptoms (67%), dystonia (18%), choreoathetosis (10%), and tremor (4%), with parkinsonism and myoclonus not reported as initial features. The prevalence of movement disorders during the course of the disease includes cerebellar symptoms (96%), dystonia (89%), parkinsonism (41%), choreoathetosis (89%), myoclonus (92%), and tremor (74%). Phenomenology and age of onset is modulated by presence of residual ATM kinase activity, with genotypes heavily truncating the ATM protein associated with the most severe phenotypes. Ataxia‐telangiectasia commonly results in a spectrum of movement disorders beyond ataxia and telangiectasias. © 2018 International Parkinson and Movement Disorder Society