bluuebunny/crossref_metadata_2025 huggingface dataset:
The fingerprint of a flow: wrinkle patterns in nonuniform coatings on pre-stretched soft foundations
Authors: Schleifer J. , Marthelot J. , Jones T. J. , Brun P.-T.
Published: January 2019

We study the wrinkle patterns obtained when applying a thin polymeric film on a uniaxially prestretched soft foundation.
Effects of CNTs on thermal transitions, thermal diffusivity and electrical conductivity in nanocomposites: comparison between an amorphous and a semicrystalline polymer matrix
Authors: Klonos Panagiotis A. , Tegopoulos Sokratis N. , Koutsiara Constantina S. , Kontou Evagelia , Pissis Polycarpos , Kyritsis Apostolos
Published: January 2019

Distinct impacts of RAFfillervs. RAFcrystal on thermal transport processes recorded in amorphous vs. semicrystalline polymer CNT-based nanocomposites.
Ultrahigh discharge efficiency and energy density achieved at low electric fields in sandwich-structured polymer films containing dielectric elastomers
Authors: Chen Jie , Wang Yifei , Xu Xinwei , Yuan Qibin , Niu Yujuan , Wang Qing , Wang Hong
Published: January 2019

A sandwich-structured film is capable of an ultra-high efficiency of 89% with an energy density of 11.8 J cm−3 at a low field of 300 MV m−1.
Verifying driver performance for heavy haulage fatigue management
Authors: Vo Son Anh , Mirowski Luke , Scanlan Joel , Turner Paul
Published: January 2019

Working performance of drivers is an important concern of commercial logistics firms as it directly relates to operational efficiency targets. However, in heavy vehicle activity, the enforcement of fatigue management rules by the Australian government can potentially influence this efficiency as the regulation scheme controls maximum work time and minimum rest time of drivers. Therefore, evaluating a driver's performance in the context of fatigue compliance is an essential need that aims to assist transport operators to increase their operational efficiencies. This research proposes a method in assessing how well a driver performs his job by using anomaly detection principles from intrusion detection systems in network security. This approach utilises output data of the logistics fatigue manager application and compliance outcomes of the fatigue compliance verification system to measure the driver's performance. In addition to performance concerns, the system also monitors safety levels based on fatigue conditions of drivers to ensure that the positive evaluation outcomes can be applied standards for the whole fleet in practice. The results highlight the opportunity to monitor driver fatigue levels for verifying fatigue risk within existing fatigue compliance requirements.
Hybrid dual Kalman filtering model for short‐term traffic flow forecasting
Authors: Zhou Teng , Jiang Dazhi , Lin Zhizhe , Han Guoqiang , Xu Xuemiao , Qin Jing
Published: January 2019

Short‐term traffic flow forecasting is a fundamental and challenging task since it is required for the successful deployment of intelligent transportation systems and the traffic flow is dramatically changing through time. This study presents a novel hybrid dual Kalman filter (H‐KF2) for accurate and timely short‐term traffic flow forecasting. To achieve this, the H‐KF2 first models the propagation of the discrepancy between the predictions of the traditional Kalman filter and the random walk model. By estimating the a posteriori state of the prediction errors of both models, the calibrated discrepancy is exploited to compensate the preliminary predictions. The H‐KF2 works with competitive time and space to traditional Kalman filter. Four real‐world datasets and various experiments are employed to evaluate the authors’ model. The experimental results demonstrate the H‐KF2 outperforms the state‐of‐the‐art parametric and non‐parametric models.
A Model to Manage Crude Palm Oil Production System
Authors: John Inyang , Magdalene Andrew-Munot , Syed Tarmizi Syed Shazali , Shirley Johnathan Tanjong
Published: January 2019

This paper reviews key production process for crude palm oil and highlights factors that highly influence the production of crude palm oil. This paper proposes a generic conceptual model for crude palm production process considering these factors. The conceptual model could be modified to consider other factors not included in this paper. The future research would be to construct a simulation model based on the conceptual model proposed in this paper and analyse the effect of these factors on the performance of crude palm oil production system.
The tuning of a small four-stroke spark ignition engine for flexible valve timings through numerical approach
Authors: Rosli M. Haziq Adham , Hanipah M. Razali , Kettner Maurice
Published: January 2019

Variable valve timing has been implemented by various manufacturers to improve internal combustion engine performance while operating at wide speed and load ranges. A novel flexible valve timing system for a small four-stroke engine is currently under development by Automotive Engineering Research Group (AERG) in Universiti Malaysia Pahang (UMP). In this paper, a comprehensive intake and exhaust tuning for the flexible variable valve timing is presented. A numerical assessment has been conducted through one dimensional engine modelling and simulation using validated model. There are eight valve timing configurations investigated for the tuning for three main speed regions. The simulation shows a positive and significant impact to the engine performance in three approaches; namely late intake valve closing, early intake valve closing and late exhaust valve closing. These approaches sufficiently covered the whole range of engine speeds for optimum engine operational performance.
Fault Detection and Diagnosis of Air Handling Unit: A Review
Authors: Leong Cheng Yew
Published: January 2019

Air-conditioning systems consumed the most energy usage nearly 45% of the total energy used in commercial-building. Where AHU is one of the most extensively operated equipment and this device is typical customize and complex which can results in hardwire failure and controller errors. The efficiency of the system is very much depending on the proper functioning of sensors. Faults arising from the sensors and control systems are a major contribution to the energy wastage. As such faults often go unnoticed for extended periods of time until the deterioration in performance becomes great enough to trigger comfort complaints or total equipment failure. Energy could be reduced if those faults can be detected and identified at early stage. This paper aims to review of various existing automated fault detection and diagnosis (AFDD) methods for an Air Handling Unit. The background of AHU system, general fault detection and diagnosis framework and typical faults in AHU is described. Comparison and evaluation of the various methodologies will be reviewed in this paper. This comparative study also reveals the strengths and weaknesses of the different approaches. The important role of fault diagnosis in the broader context of air- conditioning is also outlined. By identifying and diagnosing faults to be repaired, these techniques can benefits building owners by reducing energy consumption, improving indoor air quality and operations and maintenance.
Catalan numbers out of a stochastic cellular automaton
Authors: Białecki Mariusz
Published: January 2019

Having constructed a stochastic cellular automaton, which is a simple model of earthquakes and has a stationary state described by Motzkin numbers’ recurrence, we define a stochastic cellular automaton, whose stationary state is characterized by Catalan numbers’ recurrence. Thus we provide a new interpretation of Catalan numbers in terms of stochastic discrete dynamical systems.
Pulsed DC bias for the study of negative-ion production on surfaces of insulating materials in low pressure hydrogen plasmas
Authors: Achkasov K. , Moussaoui R. , Kogut D. , Garabedian E. , Layet J. M. , Simonin A. , Gicquel A. , Achard J. , Boussadi A. , Cartry G.
Published: January 2019

In this work, negative-ion production on the surface of a sample negatively DC biased in a hydrogen plasma is studied. The negative ions created under positive ion bombardment are accelerated toward the plasma, self-extracted, and detected according to their energy and mass, by a mass spectrometer placed in front of the sample. The use of a pulsed bias allows applying a quasi-DC bias on insulating material during a short period of time and offers the possibility to extend the measurement method to nonconductive samples. The pulsed-bias tests were performed first with highly oriented pyrolytic graphite (HOPG), a conductive material, to demonstrate the feasibility of the method. By changing the pulsed-bias frequency, it was possible to obtain HOPG material with different hydrogen surface coverages and hence different surface states leading to an increase of negative-ion production by up to 30%–50% as compared to the continuous bias case. To establish a protocol for insulating materials, charge accumulation on the surface during the bias pulse and influence of the bias duration and frequency were explored using microcrystalline diamond (MCD) thin layers. By using a pulse short enough (10 μs) at 1 kHz frequency, it has been possible to measure negative-ions on the MCD sample at a quasi-constant surface bias of 130 V, with only 1 V variation during the measurement. Negative-ion surface production on MCD has been studied in pulsed mode with surface temperature from room temperature to 800 °C. It is shown that pulsing the bias and increasing the temperature allows limiting defect creation on MCD which is favorable for negative-ion production. Consequently, at 400 °C, the yield on MCD in pulsed mode is one order of magnitude higher than the yield on HOPG in continuous mode at room temperature.
First-principles calculations on effects of Al and Ga dopants on atomic and electronic structures of amorphous Ge2Sb2Te5
Authors: Lee Dongheon , Kang Gijae , Lee Kyeongpung , Yoon Sungjoon , Kim Jeenu , Han Seungwu
Published: January 2019

Effects of post-transition metal dopants M (M = Al, Zn, and Ga) on structural and electronic properties of amorphous Ge2Sb2Te5 (a-GST) are investigated through first-principles calculations based on the density functional theory. The doped a-GST is generated through the melt-quench procedure using molecular dynamics simulations. It is found that the three dopants behave similarly in a-GST, and they are mostly coordinated by Te atoms in tetrahedral geometry, which is similar to those in crystalline MxTey. This is in contrast with crystalline GST wherein the most stable position of dopant M is the octahedral vacancy site. The number of wrong bonds such as Ge–Ge, Ge–Sb, or Sb–Sb increases as dopant atoms predominantly bond with Te atoms. The number of 4-fold ring structures, especially ABAB-type, decreases significantly, explaining the enhanced thermal stability of doped a-GST in the experiment. The bandgap estimated from density of states and the optical gap obtained from Tauc plot increase upon doping, which is also in good agreement with the experiment. By successfully relating the experimental doping effects and changes in the atomic structure, we believe that the present work can serve as a key to offer better retention and lower power consumption in phase-change memory.
Piezoelectric-based uniaxial strain cell with high strain throughput and homogeneity
Authors: Kostylev Ivan , Yonezawa Shingo , Maeno Yoshiteru
Published: January 2019

We seek for novel electronic phenomena by using external strain engineering, namely, by the application of external uniaxial strain. A piezoelectric-based uniaxial strain cell has been recently developed by Hicks et al. and successfully utilized for studies of various unconventional superconductors. Here, we propose a modified design that minimizes effects originating from the asymmetry of the strain cell design, in particular with minimal bending moments, by placing the sample at the axis of mirror symmetry of the device to balance out the reactive forces. Results of finite element analyses indicate that placing the sample offset to the axis of the mirror symmetry indeed causes an increase of strain inhomogeneity up to 10%, both at room temperature and at 4.2 K. Furthermore, we found that this bending reduces the overall achievable strain down to 30% of its maximal value without the bending. We also experimentally demonstrate the potential of our constructed device by tracking the displacement of the anvils of the strain cell with a parallel plate capacitor. The full range of motion of the piezo-stacks were demonstrated at room temperature. With a sample and at 0.9 K, we achieved a uniaxial strain of −1.5%, which is enough to induce electronic change in typical materials.
Semipolar (10-11) GaN growth on silicon-on-insulator substrates: Defect reduction and meltback etching suppression
Authors: Mantach Rami , Vennéguès P. , Perez J. Zuniga , De Mierry P. , Leroux M. , Portail M. , Feuillet G.
Published: January 2019

We demonstrate the growth of almost strain-free (10-11) semipolar GaN on silicon-on-insulator (SOI) substrates, with no meltback etching and with a defect density strongly reduced compared to semipolar templates grown on patterned silicon substrates. This is carried out using SOI substrates with a very thin (∼150 nm) 6° off (001) Si top layer. By resorting to very small nucleation (111) facets, revealed through chemical etching of the topmost thin Si layer, we are able to diminish significantly the overall dislocation density. Cathodoluminescence and scanning electron microscopy images at different stages of the growth illustrate how the defect density reduction operates and confirm the complete suppression of meltback etching over the whole 2 in. wafer. Low temperature photoluminescence and optical reflectivity indicate that complete strain relaxation is closely achieved (D0X at 3.473 ± 0.001 eV), compared to semipolar epilayers grown onto “bulk” silicon (D0X at 3.460 eV). Thanks to this efficient strain relaxation, very thick layers, up to 9 μm, could be obtained crack-free.
Drag coefficient and formation length at the onset of vortex shedding
Authors: Chopra Gaurav , Mittal Sanjay
Published: January 2019

The flow past a circular cylinder at a low Reynolds number (40 ≤ Re ≤ 180) is investigated. A stabilized finite element method is utilized to solve the incompressible flow equations in two-dimensions. The critical Re for the onset of vortex shedding (Rec) is estimated to be 46.985. The variation of time-averaged coefficient of drag (C¯D) with Re is found to be non-monotonic for Re > Rec. Unlike for the steady flow, the pressure component of C¯D increases with an increase in Re in a short range of Re for Re > Rec. This increase is due to a significant rise in the peak suction, near the shoulder of the cylinder, of the time-averaged flow, with Re. Several definitions of vortex formation length (Lf), proposed in the past, are reviewed and compared. A new definition, based on the fluctuation in the local kinetic energy of the flow, is proposed. The variation of Lf with Re is compared with Lw, the separation bubble length. Lf is found to be significantly larger than Lw for Re close to Rec. The difference between the two lengths decreases with an increase in Re. The meaning of Lf, in terms of flow physics, is explored. It is found that the vortices form in the near wake, even for Re close to Rec. They become stronger as they convect downstream and gain full strength at a location Lf downstream of the cylinder, beyond which they begin to decay.
The pure rotational spectrum of the ZnBr radical (X2Σ+): Trends in the zinc halide series
Authors: Burton M. A. , Ziurys L. M.
Published: January 2019

The pure rotational spectrum of ZnBr (X2Σ+) has been recorded in the frequency range 259–310 GHz using millimeter-wave direct absorption techniques. This study is the first quantitative spectroscopic investigation of this free radical. ZnBr was synthesized in a DC discharge by the reaction of zinc vapor in argon with one of three reagents: BrCH3, Br2CH2, or Br2. Eight rotational transitions were measured for six isotopologues (64Zn79Br, 64Zn81Br, 66Zn79Br, 66Zn81Br, 68Zn79Br, and 68Zn81Br), all of which exhibited spin-rotation interactions. Furthermore, transitions originating in the v = 1 through 3 excited vibrational states were obtained for certain isotopologues. Five rotational transitions were also recorded for 67Zn79Br, in which hyperfine splittings were observed arising from the 67Zn nucleus (I = 5/2). The spectra were analyzed using a Hund’s case (bβJ) Hamiltonian, and rotational, spin-rotation, and 67Zn magnetic hyperfine constants were determined. Equilibrium parameters were also derived for the 64Zn79Br, 64Zn81Br, 66Zn79Br, and 66Zn81Br isotopologues, including the vibrational constant, ωe = 286 cm−1. The equilibrium bond length was derived to be re = 2.268 48(90) Å. Analysis of the 67Zn hyperfine parameters suggest a decrease in ionic character in ZnBr from the other known zinc halides, ZnF and ZnCl.
Prevention of network destruction of partially hydrolyzed polyacrylamide (HPAM): Effects of salt, temperature, and fumed silica nanoparticles
Authors: Aliabadian Ehsan , Kamkar Milad , Chen Zhangxin , Sundararaj Uttandaraman
Published: January 2019

Polymer flooding is one of the most effective enhanced oil recovery (EOR) methods. High temperature and a high salt content in oil reservoirs significantly decrease the performance of polymer flooding. In this work, the viscoelastic properties of a partially hydrolyzed polyacrylamide (HPAM) solution with and without salt (NaCl) and at two different temperatures (35 °C and 70 °C) were evaluated using rheological approaches. Two fumed silica nanoparticles (NPs) featuring different surface chemistries were used, and their ability to prevent destruction of the polymer network structure against salt addition and temperature increase was investigated. Linear rheological tests (frequency sweep, creep, and creep recovery) and nonlinear rheological tests (large amplitude oscillatory shear) were employed to evaluate the network structure of these systems. The results showed that either adding salt or increasing the temperature destroyed the mechanical integrity of the HPAM 3-dimensional elastic network. However, the introduction of both types of NPs at a sufficient concentration maintained the network structure of HPAM solutions in the small deformation region. In the large deformation region, it was shown that the extent of intra-cycle shear-thickening behavior in the HPAM solution (T = 35 °C and without any salt) decreased by incorporating salt or by increasing the temperature. Moreover, upon incorporating either of the NPs to the HPAM solution, the nonlinear viscoelastic behavior dramatically changed, and the critical strain (linear to nonlinear transition) decreased to a much lower strain amplitude. The outcomes of this study will help petroleum scientists to design more efficient EOR methods.
Double-emission mechanism of laser-induced HOPG-exfoliated Graphene Quantum Dots (GQDs)
Authors: An Miao , Wu Junxiao , Wang Peijie , Fang Yan
Published: January 2019

The photoluminescence (PL) mechanism of graphene quantum dots (GQDs) has remained ambiguous, which restricts their simulations and applications. Here, stable and pure GQDs were fabricated by laser ablation of highly oriented pyrolytic graphite along the orientation parallel to the graphite layers. Two intense PL peaks were surprisingly achieved, which experimentally demonstrates that the double emissions coexist in the PL mechanism. This finding contrasts with the conventionally reported cases in which only one PL peak was observed and intensively studied. The peak at shorter wavelengths corresponds to the reported PL peak. This peak is redshifted with excitation wavelengths and is attributed to transitions from π* to π states rather than from π* to surface states as in most conventionally assigned situations. Notably, the peak at longer wavelengths is derived from the emission transition from π* to surface states and exhibits an excitation wavelength-independent feature. Because of the sufficient passivation and the resulting increase in electron density on the GQDs, the bandwidth that is composed of the energy levels of all surface states becomes narrowed and close to that of a single GQD, which causes the peak position to be insensitive to the sizes of the GQDs. Furthermore, an investigation indicates that in quite a few reported PL spectra, with an intense peak, a weak shoulder at longer wavelengths appeared with excitation wavelength-independence although this shoulder was usually ignored. This work is significant not only for true understanding of the PL mechanism but also for multi-colour photoluminescence and cancer cell imaging applications.
On the Hall-mediated resistive tearing instability of highly elongated current sheets
Authors: Vekstein Grigory
Published: January 2019

The present paper provides a comprehensive description of various regimes involved in the two-fluid model of resistive tearing instability. These include two novel regimes of this instability, which correspond to the long-wave modes that can develop in a highly elongated current sheet. This issue is relevant to the study of fast magnetic reconnection and magnetic turbulence in magnetohydrodynamic objects with a large value of the Lundquist number.
AlN-based hybrid thin films with self-assembled plasmonic Au and Ag nanoinclusions
Authors: Wang Xuejing , Nguyen Trang , Cao Yang , Jian Jie , Malis Oana , Wang Haiyan
Published: January 2019

Aluminum nitride (AlN)-based two-phase nanocomposite thin films with plasmonic Au and Ag nanoinclusions have been demonstrated using a one-step thin film growth method. Such AlN-based nanocomposites, while maintaining their wide bandgap semiconductor behavior, present tunable optical properties such as bandgap, plasmonic resonance, and complex dielectric function. Depending on the growth atmosphere, the metallic nanoinclusions self-organized into different geometries, such as nano-dendrites, nano-disks, and nanoparticles, providing enhanced optical anisotropy in-plane and out-of-plane. The infrared transmission measurements demonstrate the signature peaks of AlN as well as a broad transmission window attributed to the plasmonic nanoinclusions. This unique AlN-metal hybrid thin film platform provides a route to modulate the optical response of wide bandgap III-V nitride semiconductors towards infrared sensing or all optical based integrated circuits.
Vortex shedding from a circular cylinder in shear-thinning Carreau fluids
Authors: Bailoor Shantanu , Seo Jung-Hee , Mittal Rajat
Published: January 2019

Results from numerical simulations of two-dimensional, shear-thinning Carreau fluid flow over an unconfined circular cylinder are presented in this paper. Parametric sweeps are performed over the various Carreau model parameters, and trends of the time-averaged force coefficients and vortex characteristics are reported. In general, increased shear-thinning results in lower viscous forces on the body but greater pressure forces, resulting in a complex non-monotonic drag response. Lift forces generally increased with shear-thinning due to the dominant pressure contribution. The decrease in fluid viscosity also led to shorter vortex formation lengths and the consequent rise in the Strouhal frequency of vortex shedding. It is expected that these results will be useful for verification of computational models of unsteady non-Newtonian flows.
Diagnostic Accuracy of Early Secretory Antigenic Target-6–Free Interferon-gamma Release Assay Compared to QuantiFERON-TB Gold In-tube
Authors: Nemes Elisa , Abrahams Deborah , Scriba Thomas J , Ratangee Frances , Keyser Alana , Makhethe Lebohang , Erasmus Mzwandile , Mabwe Simbarashe , Bilek Nicole , Rozot Virginie , Geldenhuys Hennie , Hatherill Mark , Lempicki Maria D , Holm Line Lindebo , Bogardus Leah , Ginsberg Ann M , Blauenfeldt Thomas , Smith Bronwyn , Ellis Ruth D , Loxton Andre G , Walzl Gerhard , Andersen Peter , Ruhwald Morten
Published: January 2019

Background

Early secretory antigenic target-6 (ESAT-6) is an immunodominant Mycobacterium tuberculosis (M.tb) antigen included in novel vaccines against tuberculosis (TB) and in interferon-gamma (IFN-γ) release assays (IGRAs). Therefore, the availability of an ESAT-6–free IGRA is essential to determine M.tb infection status following vaccination with ESAT-6–containing vaccines. We aimed to qualify a recently developed ESAT-6–free IGRA and to assess its diagnostic performance in comparison to QuantiFERON-TB Gold In-tube (QFT).

Methods

Participants with different levels of M.tb exposure and TB disease were enrolled to determine the ESAT-6–free IGRA cutoff, test assay performance in independent cohorts compared to standard QFT, and perform a technical qualification of antigen-coated blood collection tubes.

Results

ESAT-6–free IGRA antigen recognition was evaluated in QFT-positive and QFT-negative South African adolescents. The ESAT-6–free IGRA cutoff was established at 0.61 IU/mL, based on receiver operating characteristic analysis in M.tb-unexposed controls and microbiologically confirmed pulmonary TB patients. In an independent cohort of healthy adolescents, levels of IFN-γ released in QFT and ESAT-6–free IGRA were highly correlated (P < .0001, r = 0.83) and yielded comparable positivity rates, 41.5% and 43.5%, respectively, with 91% concordance between the tests (kappa = 0.82; 95% confidence interval, 0.74–0.90; McNemar test P = .48). ESAT-6–free IGRA blood collection tubes had acceptable lot-to-lot variability, precision, and stability.

Conclusions

The novel ESAT-6–free IGRA had diagnostic accuracy comparable to QFT and is suitable for use in clinical trials to assess efficacy of candidate TB vaccines to prevent established M.tb infection.
The use of intravesical cidofovir for the treatment of adenovirus-associated haemorrhagic cystitis in a kidney transplant recipient
Authors: Ho Quan Yao , Tan Chieh Suai , Thien Siew Yee , Kee Terence , Chlebicki Maciej Piotr
Published: January 2019

Adenovirus is an important cause of haemorrhagic cystitis in kidney transplant recipients. The optimal treatment for adenovirus-associated haemorrhagic cystitis (AAHC) is unknown. Intravenous cidofovir may be effective, but nephrotoxicity is a major concern. The use of intravesical cidofovir for viral haemorrhagic cystitis has been reported in haematopoietic stem cell transplant recipients and may be associated with a lower risk of nephrotoxicity, but its use has not been reported in kidney transplant recipients. We report the use of intravesical cidofovir for the treatment of AAHC in a kidney transplant recipients, along with a review of the literature.
Modulation of temozolomide dose differentially affects T-cell response to immune checkpoint inhibition
Authors: Karachi Aida , Yang Changlin , Dastmalchi Farhad , Sayour Elias J , Huang Jianping , Azari Hassan , Long Yu , Flores Catherine , Mitchell Duane A , Rahman Maryam
Published: January 2019

Background

The changes induced in host immunity and the tumor microenvironment by chemotherapy have been shown to impact immunotherapy response in both a positive and a negative fashion. Temozolomide is the most common chemotherapy used to treat glioblastoma (GBM) and has been shown to have variable effects on immune response to immunotherapy. Therefore, we aimed to determine the immune modulatory effects of temozolomide that would impact response to immune checkpoint inhibition in the treatment of experimental GBM.

Methods

Immune function and antitumor efficacy of immune checkpoint inhibition were tested after treatment with metronomic dose (MD) temozolomide (25 mg/kg × 10 days) or standard dose (SD) temozolomide (50 mg/kg × 5 days) in the GL261 and KR158 murine glioma models.

Results

SD temozolomide treatment resulted in an upregulation of markers of T-cell exhaustion such as LAG-3 and TIM-3 in lymphocytes which was not seen with MD temozolomide. When temozolomide treatment was combined with programmed cell death 1 (PD-1) antibody therapy, the MD temozolomide/PD-1 antibody group demonstrated a decrease in exhaustion markers in tumor infiltrating lymphocytes that was not observed in the SD temozolomide/PD-1 antibody group. Also, the survival advantage of PD-1 antibody therapy in a murine syngeneic intracranial glioma model was abrogated by adding SD temozolomide to treatment. However, when MD temozolomide was added to PD-1 inhibition, it preserved the survival benefit that was seen by PD-1 antibody therapy alone.

Conclusion

The peripheral and intratumoral immune microenvironments are distinctively affected by dose modulation of temozolomide.
Top-Down Suppression of Sensory Cortex in an NMDAR Hypofunction Model of Psychosis
Authors: Ranson Adam , Broom Eluned , Powell Anna , Chen Fangli , Major Guy , Hall Jeremy
Published: January 2019

Conceptual and computational models have been advanced that propose that perceptual disturbances in psychosis, such as hallucinations, may arise due to a disruption in the balance between bottom-up (ie sensory) and top-down (ie from higher brain areas) information streams in sensory cortex. However, the neural activity underlying this hypothesized alteration remains largely unexplored. Pharmacological N-methyl-d-aspartate receptor (NMDAR) antagonism presents an attractive model to examine potential changes as it acutely recapitulates many of the symptoms of schizophrenia including hallucinations, and NMDAR hypofunction is strongly implicated in the pathogenesis of schizophrenia as evidenced by large-scale genetic studies. Here we use in vivo 2-photon imaging to measure frontal top-down signals from the anterior cingulate cortex (ACC) and their influence on activity of the primary visual cortex (V1) in mice during pharmacologically induced NMDAR hypofunction. We find that global NMDAR hypofunction causes a significant increase in activation of top-down ACC axons, and that surprisingly this is associated with an ACC-dependent net suppression of spontaneous activity in V1 as well as a reduction in V1 sensory-evoked activity. These findings are consistent with a model in which perceptual disturbances in psychosis are caused in part by aberrant top-down frontal cortex activity that suppresses the transmission of sensory signals through early sensory areas.
Diagnosis of occupational hypersensitivity pneumonitis
Authors: Morell Ferran , Ojanguren Iñigo , Cruz María-Jesús
Published: January 2019

Purpose of review

To discuss the diagnostic methods currently used in the study of patients with hypersensitivity pneumonitis, with special emphasis on the most recent contributions published in the medical literature regarding the diagnosis of occupational hypersensitivity pneumonitis (OHP). This review presents an update of the use of these diagnostic tests, a controversial issue among experts.

Recent findings

In spite of the multiple attempts at systematization and the publication of expert consensus statements, standardizing and diagnostic methods and criteria remain particularly difficult. As a result, centers tend to rely on their own experience and establish diagnosis by consensus among their multidisciplinary teams. Though recommendable in many ways, this method presents significant limitations.

Diagnosis of OHP should be made with a thorough clinical history of the symptoms and clinical signs as well as a meticulous review, if possible by an expert, of possible exposures in the working environment; a meticulous physical examination; high-resolution computed tomography of the thorax; serum determination of specific immunoglobuline Gs; bronchoalveolar lavage and possibly cryobiopsy; fungal culture; and, when appropriate, a specific inhalation challenge test with the suspected antigen.
The North Carolina Community Preceptor Experience: Third Study of Trends Over 12 Years
Authors: Latessa Robyn , Keen Susan , Byerley Julie , Foley Kathleen A. , Payne Lauren E. , Conner Kirstie T. , Tarantino Heather , Peyser Bruce , Steiner Beat D.
Published: January 2019

Purpose

To measure community-based preceptors’ overall satisfaction and motivations, the influence of students on preceptors’ practices, and compare with 2005 and 2011 studies.

Method

North Carolina primary care preceptors across disciplines (physicians, pharmacists, advanced practice nurses, physician assistants) received survey invitations via e-mail, fax, postcard, and/or full paper survey. Most questions in 2017 were the same as questions used in prior years, including satisfaction with precepting, likelihood to continue precepting, perceived influence of teaching students in their practice, and incentives for precepting. A brief survey or phone interview was conducted with 62 nonresponders. Chi-square tests were used to examine differences across discipline groups and to compare group responses over time.

Results

Of the 2,786 preceptors contacted, 893 (32.1%) completed questionnaires. Satisfaction (816/890; 91.7%) and likelihood of continuing to precept (778/890; 87.4%) remained unchanged from 2005 and 2011. However, more preceptors reported a negative influence for patient flow (422/888; 47.5%) in 2017 than in 2011 (452/1,266; 35.7%) and 2005 (496/1,379; 36.0%) (P < .0001), and work hours (392/889; 44.1%) in 2017 than in 2011 (416/1,268; 32.8%) and 2005 (463/1,392; 33.3%) (P < .0001). Importance of receiving payment for teaching increased from 32.2% (371/1,152) in 2011 to 46.4% (366/789) in 2017 (P < .0001).

Conclusions

This 2017 survey suggests preceptor satisfaction and likelihood to continue precepting have remained unchanged from prior years. However, increased reporting of negative influence of students on practice and growing value of receiving payment highlight growing concerns about preceptors’ time and finances and present a call to action.
Addressing Race, Culture, and Structural Inequality in Medical Education: A Guide for Revising Teaching Cases
Authors: Krishnan Aparna , Rabinowitz Molly , Ziminsky Ariana , Scott Stephen M. , Chretien Katherine C.
Published: January 2019

Problem

Sociodemographic identities, including race, culture, ethnicity, gender, and sexual orientation (race and culture), are recognized as important determinants of health, with significant impacts on patients’ health outcomes, but teaching medical students about this is challenging. The authors sought to identify areas for improvement in delivery of critical content about race, culture, structural inequalities, and health disparities within a set of virtual patient cases used by U.S. medical schools and develop revision guidelines.

Approach

A workgroup (medical students and faculty) conducted a literature review in 2017 to identify challenges and best practices for teaching and learning about race and culture in medicine. Using an analytic framework informed by this review, they analyzed 63 Aquifer virtual patient teaching cases for effectiveness of the presentation of race and culture, resulting in six main themes describing common mistakes or pitfalls. They then developed an evidence-based guide for systematic case revision.

Outcomes

The authors present a novel, practical guide for medical educators to use to revise existing teaching cases and improve the delivery of critical concepts surrounding race and culture. This guide includes fundamental definitions and six sections to guide structured case revision based on the main themes. It includes examples of language, suggested edits, and the rationale and evidence for recommendations.

Next Steps

Feedback from faculty and students regarding implementation of the guide and delivery of revised content in Aquifer cases will be critical in determining the guide’s effectiveness. This structured guide may be adapted to a variety of teaching modalities in medicine.
Pelvic Tilt Changes After Hamstring Lengthening in Children With Cerebral Palsy
Authors: Wijesekera Maheshi P.C. , Wilson Nichola C. , Trinca Daniele , Holmes Gillian , Bass Alfie , Wright David M. , Walton Roger
Published: January 2019

Background:

Flexion deformity of the knee is a common presentation in children with cerebral palsy with hamstring surgery as an option for addressing this. However, concerns with regard to increased pelvic tilt have been raised. The purpose of this study was to compare preoperative and postoperative pelvic tilt after isolated hamstring lengthening versus combined hamstring lengthening and the influence of Gross Motor Function Classification System (GMFCS) levels on pelvic tilt.

Methods:

This retrospective study included 46 ambulatory children with cerebral palsy who had had open medial hamstring lengthening (mean age at surgery, 11 y 11 mo; SD, 2 y 11 mo; GMFCS I, 16; GMFCS II 20; GMFCS III 10). Twelve children underwent isolated surgery and 34 children underwent combined surgery. The isolated hamstring procedures could be combined with foot and/or ankle-level surgery, as only the hamstring procedure would affect the pelvic tilt. Combined surgery was defined as hamstring lengthening with other procedures performed at the knee or more proximally. The preoperative and postoperative 3-dimensional gait analysis data were evaluated in this study.

Results:

Both the isolated and combined hamstring lengthening groups showed no significant change in pelvic tilt (∆1.28, P=0.203; ∆1.47, P=0.113, respectively). A significant change in pelvic tilt was seen in children functioning at GMFCS III (∆4.66, P=0.009) but not GMFCS I and II (∆0.37, P=0.718; ∆0.48, P=0.697). Significant postoperative decreases in the knee flexion angle at initial contact were seen for both isolated (∆5.72, P=0.010) and combined hamstring lengthening (∆10.95, P<0.001).

Conclusions:

Hamstring lengthening, for the majority of patients, did not lead to a clinically significant change in mean pelvic tilt and improved knee flexion angle at initial contact. Children who functioned at GMFCS level III had an increase in anterior pelvic tilt and caution should be exercised in this group.

Study Design:

Level IV evidence—case series.
Reflectance Confocal Microscopy Features of Plaque Psoriasis Overlap With Horizontal Histopathological Sections: A Case Series
Authors: Verzì Anna Elisa , Lacarrubba Francesco , Caltabiano Rosario , Broggi Giuseppe , Musumeci Maria Letizia , Micali Giuseppe
Published: January 2019

Reflectance confocal microscopy (RCM) displays horizontal, en face tissue sections of the epidermis and upper dermis, and interpretation of its features is classically based on the comparison with vertical conventional histopathological sections that, as known, do not reflect the same plane of observation. In 10 patients affected by psoriasis, we correlated RCM images with horizontal histopathological sections from skin biopsies, observing in all cases marked overlaps between the 2 techniques. Although vertical section examination remains the gold standard for the diagnosis of psoriasis, this novel comparative approach may contribute to a more precise definition of RCM findings and could represent the drive for further research as well as an innovative tool for educational purposes.
Exploring Patient Experience of Facial Nerve Palsy to Inform the Development of a PROM
Authors: Norris Jonathan H. , Longmire Natasha M. , Kilcoyne Sarah , Johnson David , Fitzpatrick Ray , Klassen Anne F.
Published: January 2019

Background:

There is currently a mandate globally to incorporate patient’s perceptions of their illness into outcome measures, in order to provide a deeper insight into medical practice. Facial nerve palsy (FNP) is a devastating condition that can significantly impact quality of life. However, no measure currently exists that comprehensively assesses outcome in FNP using patient perception. The aim of this study is to explore patients’ experiences of FNP with the aim of informing the development of a patient-reported outcome measure.

Methods:

Presented is a qualitative study, using in-depth semi-structured interviews with FNP patients. An interview guide was developed using expert opinion and a literature review. Interpretative description was used as the qualitative approach. Interviews were audio-recorded, transcribed, and coded line-by-line. Codes were refined using the constant comparison approach. Interviews continued until data saturation was reached. The data were used to develop a conceptual framework of patient perceived issues relating to FNP.

Results:

The sample included 5 men and 9 women aged 57.7 years (range, 36–78) with a range of causes of FNP, including Bell’s palsy (n = 5), acoustic neuroma (n = 3), trauma (n = 2), meningioma (n = 1), muscular dystrophy (n = 1), congenital (n = 1), and Ramsay Hunt syndrome (n = 1). Analysis of the 14 participant interviews led to identification of 5 major domains including “facial function concerns,” “appearance concerns,” “psychological function,” “social function,” and “experience of care.”

Conclusion:

This study provides a conceptual framework covering outcomes that matter to patients with FNP, which can be used to inform the development of a new comprehensive FNP-specific patient-reported outcome measure.
Immediate Dental Implantation in Oncologic Jaw Reconstruction: Workflow Optimization to Decrease Time to Full Dental Rehabilitation
Authors: Allen Robert J. , Shenaq Deana S. , Rosen Evan B. , Patel Snehal G. , Ganly Ian , Boyle Jay O. , Nelson Jonas A. , Matros Evan
Published: January 2019

Full dental rehabilitation following segmental mandibulectomy or maxillectomy for oncologic tumor ablation should be the goal for every patient. But despite advances in technology and reconstructive techniques, many patients do not achieve timely or complete oral rehabilitation. Recognizing this fault, we recently adopted an innovative workflow to increase the number of patients undergoing dental restoration, irrespective of tumor pathology or need for adjuvant radiotherapy. Preoperatively, every osseous jaw reconstruction undergoes virtual surgical planning to incorporate the placement of endosseous implants into the fibula osteocutaneous free flap. The dental implants are then placed intraoperatively at the time of tumor ablation and reconstruction. Four-to-six weeks following the initial surgery, the patient returns to the operating room for vestibuloplasty and exposure of the dental implants. Within 3 days of the vestibuloplasty, a temporary dental prosthesis is placed in the dental clinic, and the patient can then begin radiation therapy if needed. Following adjuvant radiation therapy, the temporary prosthesis can be replaced with a permanent one. At our institution, this innovative workflow has allowed for earlier aesthetic restoration of the jaw and greatly expanded the number of patients able to achieve oral rehabilitation. Herein, we describe this innovative workflow and provide technical pearls for successful execution.
THE TEXAS TACO TECHNIQUE FOR INTERNAL LIMITING MEMBRANE FLAP IN LARGE FULL-THICKNESS MACULAR HOLES
Authors: Major James C. , Lampen Shaun I. R. , Wykoff Charles C. , Ou William C. , Brown David M. , Wong Tien P. , Shah Ankoor R.
Published: January 2019

Purpose:

To determine the efficacy of a novel application of a surgical internal limiting membrane flap technique that requires no additional surgical adjuvants in closure of large full-thickness macular holes (FTMHs).

Methods:

The electronic medical records of patients (n = 8) with large (>400 µm) FTMHs repaired with the “Texas Taco” technique were retrospectively reviewed.

Results:

Operated patients had a mean age of 63.8 ± 19.2 (range, 19–80) years. There were five (62.5%) phakic and three (37.5%) pseudophakic eyes preoperatively. Mean follow-up time was 9.1 ± 4.7 (1.5–14.5) months. Across all patients, mean FTMH diameter at the shortest and greatest widths were 529 ± 101 (404–661) and 1,189 ± 290 (829–1,656) µm, respectively. Mean best-corrected logarithm of the minimum angle of resolution visual acuity was 1.3 ± 0.23 preoperatively (approximately Snellen acuity 20/400) and 0.66 ± 0.40 postoperatively (approximately Snellen acuity 20/100) (P < 0.001). All FTMHs remained closed at all postoperative visits.

Conclusion:

The Texas Taco technique provided anatomical and functional improvement in challenging cases of large FTMHs without the need of additional surgical adjuvants.
CLINICAL APPLICATION OF MULTICOLOR IMAGING IN CENTRAL SEROUS CHORIORETINOPATHY
Authors: He Lu , Chen Changzheng , Yi Zuohuizi , Wang Xiaoling , Liu Juejun , Zheng Hongmei
Published: January 2019

Purpose:

To characterize features of central serous chorioretinopathy (CSC) using multicolor (MC) imaging and to compare the efficacy of using MC imaging and traditional color fundus photography (CFP) for detecting features of CSC.

Methods:

A retrospective review of 75 eyes of 69 participants with CSC from the Eye Center of the Renmin Hospital of Wuhan University. The patients underwent same-day CFP, fundus fluorescein angiography (FFA), spectral domain optical coherence tomography (SD-OCT), and MC imaging (including infrared reflectance (IR), green reflectance (GR), blue reflectance (BR), combined standard MC image, and green-blue–enhanced image). Positive CSC lesions were evaluated using FFA and SD-OCT. Features in images of CFP, standard MC, green-blue–enhanced, IR, GR, and BR were analyzed and calculated.

Results:

Among the 75 eyes of 69 patients, 75 eyes with subretinal fluid (SRF) and retinal pigment epithelial (RPE) leakage point, and 43 eyes with RPE damage were observed by FFA and SD-OCT. The detection rate of SRF was significantly higher with the standard MC image (92.0%), green-blue–enhanced image (92.0%), IR (88.0%), and GR (88.0%) than that with CFP (66.7%) (P < 0.05). Blue reflectance (45.3%) was associated with lower rate of SRF detection compared to CFP (P < 0.05). The standard MC image (84.0%), green-blue–enhanced image (84.0%), IR (78.7%), and GR (80%) delineated the boundaries of SRF more effectively than CFP (44%). The abnormal areas corresponding to RPE leakage points on FFA were observed with the standard MC image, green-blue–enhanced image, and IR at detection rates of 90.7, 82.7, and 90.7%, respectively, which were significantly higher than with CFP (29.3%) (P < 0.05). However, the detection rates of the abnormalities corresponding to leakage on FFA were lower with GR (5.3%) and BR (1.3%) than those with CFP (P < 0.05). Areas of RPE damage on FFA were observed at the same locations with the standard MC image, green-blue–enhanced image, and IR at detection rates of 97.7, 93.0, and 95.3%, respectively, which were significantly higher than with CFP (41.9%) (P < 0.05). Compared with CFP, the detectable rates of RPE damage on GR (14.0%) and BR (9.3%) were lower (P < 0.05).

Conclusion:

As an adjunct to SD-OCT, the MC image can delineate the extent or boundaries of SRF more effectively than CFP. As an adjunct to FFA, the MC image can identify foci of leakage more effectively than CFP. The MC image, particularly the IR channel, can identify areas of RPE damage more effectively than CFP. Therefore, the MC image may be a useful adjunct to FFA and OCT for detecting or monitoring CSC.