bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of molecular phenotypic descriptors of breast capsular contracture formation using informatics analysis of the whole genome transcriptome
Authors: Kyle Daniel J. T. , Harvey Alison G. , Shih Barbara , Tan Kian T. , Chaudhry Iskander H. , Bayat Ardeshir 
Published: August 2013

AbstractBreast capsular contracture formation following silicone implant augmentation/reconstruction is a common complication that remains poorly understood. The aim of this study was to identify potential biomarkers implicated in breast capsular contracture formation by using, for the first time, whole genome arrays. Biopsy samples were taken from 18 patients (23 breast capsules) with Baker Grade I–II (Control) and Baker Grade III–IV (Contracted). Whole genome microarrays were performed and six significantly dysregulated genes were selected for further validation with quantitative reverse transcriptase polymerase chain reaction and immunohistochemistry. Hematoxylin and eosin was also carried out to compare the histological characteristics of control and contracted samples. Microarray results showed that aggrecan, tissue inhibitor of metalloproteinase 4 (TIMP4), and tumor necrosis factor superfamily (ligand) member 11 were significantly down‐regulated in contracted capsules; while matrix metallopeptidase 12, serum amyloid A 1, and interleukin 8 (IL8) were significantly up‐regulated. The dysregulation of aggrecan, tumor necrosis factor superfamily (ligand) member 11, TIMP4, and IL8 was validated by quantitative reverse transcriptase polymerase chain reaction (p < 0.05). Immunohistochemistry confirmed an increased protein expression for IL8 and matrix metallopeptidase 12 in contracted capsules (p < 0.05), and decreased protein expression of TIMP4 (p < 0.05). This study has shown, for the first time, a number of unique biomarkers of significance in capsular contracture formation. IL8 and TIMP4 may serve as potential key diagnostic, therapeutic, and prognostic biomarkers in capsular contracture formation.
Three-dimensional counter-examples to the Nash problem
Authors: de Fernex Tommaso 
Published: August 2013

AbstractThe Nash problem asks about the existence of a correspondence between families of arcs through singularities of complex varieties and certain types of divisorial valuations. It has been positively settled in dimension 2 by Fernández de Bobadilla and Pe Pereira, and it was shown to have a negative answer in all dimensions ${\geq }4$ by Ishii and Kollár. In this note we discuss examples which show that the problem has a negative answer in dimension 3 as well. These examples also bring to light the different nature of the problem depending on whether it is formulated in the algebraic setting or in the analytic setting.
Ba2+‐ and bupivacaine‐sensitive background K+ conductances mediate rapid EPSP attenuation in oligodendrocyte precursor cells
Authors: Chan Chu‐Fang , Kuo Tzu‐Wei , Weng Ju‐Yun , Lin Yen‐Chu , Chen Ting‐Yu , Cheng Jen‐Kun , Lien Cheng‐Chang 
Published: August 2013

Key points
We developed detailed passive cable models of rat oligodendrocyte precursor cells (OPCs) based on dual somatic recordings and complete morphological reconstructions.
Both specific membrane capacitance and specific axial resistivity are comparable to those of central neurons, but the average specific membrane resistance (Rm∼4.1 kΩ cm2) is substantially lower in OPCs.
Large Ba2+‐ and bupivacaine‐sensitive background K+ conductances contribute to the low Rm.
Simultaneous dual soma and process whole‐cell recordings reveal powerful voltage attenuation along OPC processes, indicating that OPC processes are a strong voltage attenuator.
The low Rm also sharpens EPSPs and thus narrows the temporal window for EPSP integration.
Abstract  Glutamatergic transmission onto oligodendrocyte precursor cells (OPCs) may regulate OPC proliferation, migration and differentiation. Dendritic integration of excitatory postsynaptic potentials (EPSPs) is critical for neuronal functions, and mechanisms regulating dendritic propagation and summation of EPSPs are well understood. However, little is known about EPSP attenuation and integration in OPCs. We developed realistic OPC models for synaptic integration, based on passive membrane responses of OPCs obtained by simultaneous dual whole‐cell patch‐pipette recordings. Compared with neurons, OPCs have a very low value of membrane resistivity, which is largely mediated by Ba2+‐ and bupivacaine‐sensitive background K+ conductances. The very low membrane resistivity not only leads to rapid EPSP attenuation along OPC processes but also sharpens EPSPs and narrows the temporal window for EPSP summation. Thus, background K+ conductances regulate synaptic responses and integration in OPCs, thereby affecting activity‐dependent neuronal control of OPC development and function.
Short‐term exercise training augments α2‐adrenoreceptor‐mediated sympathetic vasoconstriction in resting and contracting skeletal muscle
Authors: Jendzjowsky Nicholas G. , DeLorey Darren S. 
Published: August 2013

Key points
Postsynaptic α1‐ and α2‐adrenoreceptors produce tonic vasoconstriction in resting and contracting skeletal muscle.
Muscular contraction attenuates sympathetic vasoconstriction (functional sympatholysis). The blunting of sympathetic vasoconstriction during contraction has been mechanistically linked to a reduction in postsynaptic α1‐ and α2‐adrenoreceptor responsiveness and nitric oxide.
We recently demonstrated that exercise training augmented sympathetic vasoconstrictor responsiveness and functional sympatholysis. Whether these vascular adaptations were mediated by changes to postsynaptic adrenoreceptors was not investigated.
The present findings demonstrate that exercise training augmented α2‐adrenoreceptor‐ mediated vasoconstriction in resting and contracting skeletal muscle.
These data indicate that exercise training alters the relative contributions of α‐adrenoreceptors to sympathetic vasoconstriction in resting and contracting skeletal muscle and that the regulation of sympathetic vasoconstriction becomes more complex following exercise training.
Abstract  We hypothesized that exercise training (ET) would alter α2‐adrenoreceptor‐mediated sympathetic vasoconstriction. Sprague‐Dawley rats (n= 30) were randomized to sedentary (S), mild‐ (M) or heavy‐intensity (H) treadmill ET groups (5 days per week for 4 weeks). Following the ET component of the study, rats were anaesthetized, and instrumented for lumbar sympathetic chain stimulation, triceps surae muscle contraction and measurement of femoral vascular conductance (FVC). The percentage change of FVC in response to sympathetic stimulation was determined at rest and during contraction in control, α2 blockade (yohimbine) and combined α2+ nitric oxide (NO) synthase (NOS) blockade (Nω‐nitro‐l‐arginine methyl ester hydrochloride, l‐NAME) conditions. ET augmented (P < 0.05) sympathetic vasoconstrictor responses at rest and during contraction. Yohimbine reduced (P < 0.05) the vasoconstrictor response in ET rats at rest (M: 2 Hz: 8 ± 2%, 5 Hz: 9 ± 4%; H: 2 Hz: 14 ± 5%, 5 Hz: 11 ± 6%) and during contraction (M: 2 Hz: 9 ± 2%, 5 Hz: 9 ± 5%; H: 2 Hz: 8 ± 3%, 5 Hz: 6 ± 6%) but did not change the response in S rats. The addition of l‐NAME caused a larger increase (P < 0.05) in the vasoconstrictor response in ET than in S rats at rest (2 Hz: S: 8 ± 2%, M: 15 ± 3%, H: 23 ± 7%; 5 Hz: S: 8 ± 5%, M: 15 ± 3%, H: 17 ± 5%) and during contraction (2 Hz: S: 9 ± 3%, M: 18 ± 3%, H: 22 ± 6%; 5 Hz: S: 9 ± 5%, M: 22 ± 4%, H:26 ± 9%). Sympatholysis was greater (P < 0.05) in ET than in S rats. Blockade of α2‐adrenoreceptors and NOS reduced (P < 0.05) sympatholysis in ET rats, but had no effect on sympatholysis in S rats. In conclusion, ET increased α2‐mediated vasoconstriction at rest and during contraction.
The fast exercise drive to breathe
Authors: Duffin James 
Published: August 2013

AbstractThis paper presents a personal view of research into the exercise drive to breathe that can be observed to act immediately to increase breathing at the start of rhythmic exercise. It is based on a talk given at the Experimental Biology 2013 meeting in a session entitled ‘Recent advances in understanding mechanisms regulating breathing during exercise’. This drive to breathe has its origin in a combination of central command, whereby voluntary motor commands to the exercising muscles produce a concurrent respiratory drive, and afferent feedback, whereby afferent information from the exercising muscles affects breathing. The drive at the start and end of rhythmic exercise is proportional to limb movement frequency, and its magnitude decays as exercise continues so that the immediate decrease of ventilation at the end of exercise is about 60% of the immediate increase at the start. With such evidence for the effect of this fast drive to breathe at the start and end of rhythmic exercise, its existence during exercise is hypothesised. Experiments to test this hypothesis have, however, provided debatable evidence. A fast drive to breathe during both ramp and sine wave changes in treadmill exercise speed and grade appears to be present in some individuals, but is not as evident in the general population. Recent sine‐wave cycling experiments show that when cadence is varied sinusoidally the ventilation response lags by about 10 s, whereas when pedal loading is varied ventilation lags by about 30 s. It therefore appears that limb movement frequency is effective in influencing ventilation during exercise as well as at the start and end of exercise.
Online correction of licking‐induced brain motion during two‐photon imaging with a tunable lens
Authors: Chen Jerry L. , Pfäffli Oliver A. , Voigt Fabian F. , Margolis David J. , Helmchen Fritjof 
Published: August 2013

Key points
In order to understand the underlying behaviour of neuronal circuit dynamics, it is necessary to monitor brain activity in the awake, behaving animal.
Licking to obtain water reward is an approach that is often used to measure an animal's decision during reward‐based behaviour tasks.
In head‐fixed mice, licking produces stereotyped brain motion that interferes with two‐photon calcium imaging of neuronal activity.
We describe a method to provide online optical correction of licking‐induced brain motion during two‐photon imaging using refocusing with an electrically tunable lens.
Online correction of licking‐induced brain motion improves the measurement of neuronal activity during reward‐based behaviour.
Abstract  Two‐photon calcium imaging in awake, head‐fixed animals enables the measurement of neuronal activity during behaviour. Often, licking for the retrieval of water reward is used as a measurable report of the animal's decision during reward‐driven behaviour. However, licking behaviour can induce severe motion artifacts that interfere with two‐photon imaging of cellular activity. Here, we describe a simple method for the online correction of licking‐induced focus shifts for two‐photon calcium imaging of neocortical neurons in the head‐fixed mouse. We found that licking causes a stereotyped drop of neocortical tissue, shifting neurons up to 20 μm out of focus. Based on the measurement of licking with a piezo film sensor, we developed a feedback model, which provides a corrective signal for fast optical focus adjustments with an electrically tunable lens. Using online correction with this feedback model, we demonstrate a reduction of licking‐related focus changes below 3 μm, minimizing motion artifact contamination of cellular calcium signals. Focus correction with a tunable lens is a simple and effective method to improve the ability to monitor neuronal activity during reward‐based behaviour.
MarkUs: An Open-Source Web Application to Annotate Student Papers On-Line
Authors: Magnin Morgan , Moreau Guillaume , Varoquaux Nelle , Vialle Benjamin , Reid Karen , Conley Mike , Gehwolf Severin 
Published: August 2013

A critical component of the learning process lies in the feedback that students receive on their work that validates their progress, identifies flaws in their thinking, and identifies skills that still need to be learned. Many higher-education institutions have developed an active pedagogy that gives students opportunities for different forms of assessment and feedback. This means that students have numerous lab exercises, assignments, and projects. Both instructors and students thus require effective tools to efficiently manage the submission, assessment, and individualized feedback of students’ work. The open-source web application MarkUs aims at meeting these needs: it facilitates the submission and assessment of students’ work. Students directly submit their work using MarkUs, rather than printing it, or sending it by email. The instructors or teaching assistants use MarkUs’s interface to view the students’ work, annotate it, and fill in a marking rubric. Students use the same interface to read the annotations and learn from the assessment. Managing the students’ submissions and the instructors assessments within a single online system, has led to several positive pedagogical outcomes: the number of late submissions has decreased, the assessment time has been drastically reduced, students can access their results and read the instructor’s feedback immediately after the grading process is completed. Using MarkUs has also significantly reduced the time that instructors spend collecting assignments, creating the marking schemes, passing them on to graders, handling special cases, and returning work to the students.
In this paper, we introduce MarkUs’ features, and illustrate their benefits for higher education through our own teaching experiences and that of our colleagues. We also describe an important benefit of the fact that the tool itself is open-source. MarkUs has been developed entirely by students giving them a valuable learning opportunity as they work on a large software system that real users depend on. Virtuous circles indeed arise, with former users of MarkUs becoming developers and then supervisors of further development.
We will conclude by drawing perspectives about forthcoming features and use, both technically and pedagogically.
Study of the Static and Dynamic Performance of Rectangular Air Pads by Means of Lumped Parameters Models
Authors: Belforte Guido , Colombo Federico , Raparelli Terenziano , Trivella Andrea , Viktorov Vladimir 
Published: August 2013

Externally pressurized gas bearings are widely used in linear guide-ways for measuring machines and precision positioning systems. The number and the diameter of the supply orifices and their position strongly influence the characteristic of the pad. Usually during the design process of a pad a distributed parameters model is used to simulate the pressure distribution under the pad because it doesn’t exist a general formula suitable for all possible geometries. Analytical methods can be applied for simplified geometries to calculate static and dynamic performance of pneumatic bearings. Analytical and lumped parameters models are of faster implementation with respect to distributed parameters models and are easier to implement in the design process.
The present paper proposes different lumped parameters models to obtain the static and dynamic characteristics of pneumatic pads. These methods can be used in order to optimize the stiffness in correspondence of the operating conditions. Rectangular air pads of size 30×60 mm are considered. The results are compared with that obtained with a distributed parameters model to estimate the accuracy of the models.
Dynamic Mechanical Characterization of CF/GF Hybrid Reinforced Polymeric Composite Structures
Authors: Luca Motoc Dana 
Published: August 2013

The importance of dynamic mechanical analysis (DMA) as a research tool in the study of polymeric composite structures behavior has been already demonstrated in the literature. Many papers were approaching the relaxation phenomenon within the polymer based composite structures and thereby their behavior under various conditions of stress and temperature. Supplementary, the effect of fillers geometry, orientation and volume fraction have been extensively approached while considering the micromechanical level and their role in the mechanical properties were suitable stated. Hybridization of two different fillers has proven to an effective method in material design allowing their developers to tailor their properties according to the application driven imposed requirements.
The herein paper attempts to present a comparative study centered on the development and characterization of a hybrid polymeric composite structures made up from different combinations of carbon and glass fibers by evaluating their dynamic mechanical properties.
The samples were measured using the Dynamic Mechanical Analyzer (DMA) from NETZSCH-DMA 242 C, in the 3-point bending mode, nitrogen atmosphere, at a scanning rate of 3 K/min from −40 to 180° C with a fixed frequency of 1 Hz. Storage and loss modulus, loss tangent were recorded as function of temperature both on longitudinal and transverse direction of the unidirectional carbon fibers, in two consecutive heating cycles. A reference sample was set up to aid the comparison analysis, made entire from one filler type.
The effect of the fillers type, fillers relative volume fraction and temperature on the storage and loss moduli will be deeply investigated.
Experimental Characterization of a Permanent Magnet Magnetorheological Clutch for Automotive Applications
Authors: Bucchi Francesco , Forte Paola , Frendo Francesco 
Published: August 2013

In this work a magnetorheological clutch prototype with a permanent magnet is presented and the torque transmitted in several operating configurations is obtained by a specifically designed test bench. The clutch prototype was designed in order to have the possibility to disengage the vacuum pump which operates the power brake in diesel engines continuously. Torque transmission and size specifications were suggested by the specific application. A permanent magnet was used in order to obtain a fail-safe operation and particular attention was focused on materials selection in order to maximize torque transmission in the engaged mode and to minimize power consumption when the clutch is disengaged.
Tests were carried out on the test bench, in which electric motors apply the driving and braking torques to the primary and secondary shaft of the clutch; the transmitted torque was measured by a torque-meter at several rotational speeds. Experimental results are discussed in the paper with reference to classical literature models. The experimental tests gave also useful indications on possible improvements in the clutch design, especially regarding the seals, which have to prevent leakages at the working fluid pressure and to keep the friction losses low.
Design of a New Mechanical Variable Valve Actuation System for Motorcycle Engines
Authors: Abagnale Carmelina , Migliaccio Mariano , Pennacchia Ottavio 
Published: August 2013

This paper deals with design and manufacturing of a mechanical variable valve actuation (VVA) system, developed as part of a MUR financed research project concerning the realization of a high performance motorcycle engine, through a partnership of Moto Morini (Bologna), Dell’Orto (Milano), Istituto Motori - CNR (Napoli) and DiME (Department of Mechanical Engineering and Energetics) – University of Napoli Federico II.
After a synthetic description of the main variable valve actuation methods currently employed, the paper presents the results of our mechanical VVA system, consisting of three main elements: cam, main rocker arm with fixed fulcrum and secondary rocker arm with mobile fulcrum. This VVA system (system 1) enables valve lift variation by a simple translation of one of the three elements (the intermediate one). The study has been conducted implementing a numerical procedure specifically designed to determine cam profile and kinematic and dynamic characteristics of the whole system, starting from the following input data: rocker arm geometry, relative positions and inertial data of elements, spring stiffness and preloading, camshaft speed and valve lift law. The model has been validated against the conventional timing system using kinematic simulations. Results of the numerical procedure verify the validity of the VVA system, capable of a valve lift variation, with a limited acceleration. Starting from the numerical results, we have developed a new mechanical variable valve actuation system (system 2): it consists of the same three elements used previously, but they are connected in a different way. The newer system enables more general lift profile distributions with a similar geometric complexity. The activity has been extended to research for a new solution (always a mechanical system), capable to allow inlet valves complete closing and timing and duration variation (system 3).
This paper reports results reachable with the simplest system 1, that gives better perspectives of use for a new two-wheel vehicle engine.
A Functional Approach to Optimal Dimensioning of Automotive Transmission Shafts
Authors: Lanzotti Antonio , Patalano Stanislao , Rufrano Vito 
Published: August 2013

The paper deals with a functional approach to optimal dimensioning of automotive transmission shafts. In particular, the paper summarizes the results of a research activity developed on automotive transmission shafts to reduce the unpleasant movement of the transmission lever known as “shift lever movement”. The design problem was faced by focusing the axial clearances of the wheels assembled on the transmission shaft.
First, the functional approach to optimal dimensioning proceeds from the study of different working conditions of the automotive manual transmission and focuses on corresponding geometrical constraints and design parameters. Then, it uses simplified schemes, each of them related to a different working condition, to set a series of functional dimensioning loops for the transmission shaft. Subsequently, the approach introduces an appropriate index to evaluate the Information Content for each dimensioning scheme and it addresses the optimal dimensioning scheme, related to the minimization of the Information Content. After this, the approach foresees worst-case to check the axial clearances of the wheels assembled on the shaft. In a such way the effect of the dimensioning are directly evaluated in terms of performances of the transmission. In fact, the reduction of axial clearances for the wheels assembled on the shaft causes a direct reduction of the “shift lever movement”.
The functional approach to optimal dimensioning is applied to an automotive transmission set and the proposed dimensioning schema of the shaft is compared with different dimensioning schemes including one currently used in an international automotive company. A final discussion of the results, in terms of reduction of axial clearances of the parts assembled on the shaft, is provided.