bluuebunny/crossref_metadata_2025 huggingface dataset:
Changes in Turkey Femora Mechanical Properties Resulting From Selective Breeding for Body Weight
Authors: Zhong Ziwei , Agcaoglu Serife , Muckley Matthew , Zhao Hansi , Karcher Darrin , Orth Michael , Lilburn Michael , Akkus Ozan
Published: June 2018

Bone plays an integral role in movement and organ protection. To accomplish these tasks successfully, bone must not only be able to withstand daily fatigue loading, but also have a safety margin for unexpected high loads. The two major inputs that determine bone structure are genetics and environmental stresses [1]. Excessive stresses on bone are dissipated through the formation of microcracks [1]. When the remodeling dynamics are altered, problems such as trabecular and cortical thinning, and inadequate microcrack repair may occur, ultimately leading to bone failure [1].
Interrupted Treatment With Growth Factors in Combination With Hydrodynamic Forces Enhances ECM Deposition in Tissue-Engineered Cartilage
Authors: Yang Yueh-Hsun , Barabino Gilda A.
Published: June 2018

Achievement of viable engineered tissues through in-vitro cultivation in bioreactor systems requires a thorough understanding of the complex interplay between mechanical forces and biochemical cues. Briefly, bioreactors have been employed to impart mechanical stimuli to support tissue growth and development. Continuous fluid-induced shear stress, for example, has been shown to influence morphology and properties of engineered cartilage.1 Fluid flow enhances mass transfer mechanisms and simultaneously provides mechanical stimuli across or through the construct to emulate shear forces that occur in the knee or other joints. Critical biochemical factors, such as growth factors, are secreted by cells2,3 and involved in cell-to-cell signaling. Guided by these molecules, cells can communicate with each other and work synergistically to accomplish a specific task. It has also been demonstrated that the pathways of certain growth factors, such as transforming growth factor-β (TGF-β) family and insulin-like growth factor-1 (IGF-1), are responsive to shear stress, resulting in enhanced cell and tissue activities, and their expression is also up-regulated by fluid-induced shear stress.4,5 This evidence suggests their involvement in mechanotransduction mechanisms. However, a combination of mechanical and biochemical stimuli results in a complex culture environment which is not yet fully characterized. The present study was designed to obtain an understanding of the combined effects of hydrodynamic forces and growth factors on cartilage regeneration by employing a custom-designed wavy-walled bioreactor1 (WWB) and by selecting IGF-1 and TGF-β1 as two model molecules. We hypothesized that bioprocessing conditions which optimize mechanical, biochemical and compositional properties of tissue-engineered cartilage can be achieved under hydrodynamic stimuli in combination with an appropriate use of IGF-1 or TGF-β.
Computational Fluid Dynamics Modeling of Upper Airway During Tidal Breathing Using Volume-Gated MRI in OSAS and Control Subjects
Authors: Persak Steven C. , Sin Sanghun , Arens Raanan , Wootton David M.
Published: June 2018

Three-dimensional (3D) computational fluid dynamic (CFD) analysis was used to model the effect of collapsing airway geometry on internal pressure and velocity in the pharyngeal airway of sedated obese children with and without obstructive sleep apnea syndrome (OSAS). Geometry was reconstructed from volume-gated magnetic resonance images during normal tidal breathing of the respiratory cycle and solved using flow data averaged over 12 consecutive breathing cycles. In the OSAS subject, collapse initiated in the proximal nasopharynx and continued downstream into the oropharynx, while the control experienced negligible collapse. Tube laws (pressure vs. cross-section area) derived for the nasopharynx and oropharynx, indicated the oropharynx in the OSAS subject more compliant than the nasopharynx (1.028 mm2/Pa vs. 0.449 mm2/Pa) and had a lower theoretical limiting flow rate, confirming the oropharynx as the flow-limiting segment of the airway in this subject. This new method may help to differentiate anatomical and functional factors in airway collapse.
Aortic Hemodynamics and Endothelial Gene Expression: An Animal Specific Approach
Authors: Lim Yi Chung , Long David S.
Published: June 2018

Atherosclerosis is a major cause of morbidity and mortality in the developed world. This disease is identified by endothelial dysfunction, inflammation and the accumulation of lipids and cellular elements within the intima of medium and large-sized arteries. Within these arteries, the distribution of atherosclerotic lesions is non-uniform; the inner wall of curved sections and the outer walls of bifurcations are susceptible sites. Evidence suggests that the focal nature of the disease is mediated in part by local fluid mechanical stresses at the interface between flowing blood and the vessel wall. Strategically located at this interface is the monolayer of cells known as the endothelium. Although it was once considered to be an inert cell layer, the endothelium is a highly complex and metabolically dynamic cell layer. As a result, local fluid mechanical stresses at the wall of arteries may alter the phenotype of endothelial cells (ECs). With that in mind, the aim of this study is to better characterize the modulation of the endothelial cell phenotype in response to blood flow induced wall shear stress (WSS).
Higher Order Texture Correlation Algorithms for Cell Mechanics
Authors: Lim Kai Y. , Neu Corey P.
Published: June 2018

Texture correlation, a modified digital image correlation procedure, utilizes the natural texture of biological tissues to measure displacement fields between two consecutive digital images [1]. This algorithm is based on the assumption that a pixel within an image can be characterized by a unique intensity pattern of a subset of pixels surrounding it. The displacement of the unique subset can be tracked by comparing the reference and deformed image.
Fiber Angle and Aspect Ratio Influence the Shear Mechanics of Electrospun Nanofibrous Scaffolds
Authors: Driscoll Tristan P. , Nerurkar Nandan L. , Jacobs Nathan T. , Elliott Dawn M. , Mauck Robert L.
Published: June 2018

Fibrocartilages, including the meniscus of the knee and annulus fibrosus (AF) of the intervertebral disc, are dense connective tissues with an organized collagenous structure that play critical roles in motion and load transmission across joints. Proper mechanical function of these tissues is dependent on their structure and composition, both of which are compromised with degeneration. Tissue engineering strategies present a promising alternative to current treatments. Aligned electrospun scaffolds show promise for tissue engineering of fibrous soft tissues due to their ability to direct cell alignment and matrix deposition [1]. Furthermore, this matrix deposition results in constructs with near-native tensile properties. However, the large multi-directional forces experienced by these tissues in vivo requires that engineered constructs resist considerable shear and compressive loads as well. Unfortunately, shear properties of electrospun scaffolds are not well established. Simple shear is an appealing testing configuration because the application of tensile prestrain allows for combined fiber stretch and shear as occurs in situ. However, due to possible strain field heterogeneity, proper analysis of strain distributions must be performed [2]. The objective of this study was to quantify the effects of fiber orientation and sample aspect ratio on the shear properties of aligned electrospun scaffolds.
Collagen Fiber Alignment and Maximum Principal Strain in the Glenohumeral Capsule Predict Location of Failure During Uniaxial Extension
Authors: Luu Kelvin , Voycheck Carrie A. , McMahon Patrick J. , Debski Richard E.
Published: June 2018

The glenohumeral joint is frequently dislocated causing injury to the glenohumeral capsule (axillary pouch (AP), anterior band of the inferior glenohumeral ligament (AB-IGHL), posterior band of the inferior glenohumeral ligament (PB-IGHL), posterior (Post), and anterosuperior region (AS)). [1, 2] The capsule is a passive stabilizer to the glenohumeral joint and primarily functions to resist dislocation during extreme ranges of motion. [3] When unloaded, the capsule consists of randomly oriented collagen fibers, which play a pertinent role in its function to resist loading in multiple directions. [4] The location of failure in only the axillary pouch has been shown to correspond with the highest degree of collagen fiber orientation and maximum principle strain just prior to failure. [4, 5] However, several discrepancies were found when comparing the collagen fiber alignment between the AB-IGHL, AP, and PB-IGHL. [3,6,7] Therefore, the objective was to determine the collagen fiber alignment and maximum principal strain in five regions of the capsule during uniaxial extension to failure and to determine if these parameters could predict the location of tissue failure. Since the capsule functions as a continuous sheet, we hypothesized that maximum principal strain and peak collagen fiber alignment would correspond with the location of tissue failure in all regions of the glenohumeral capsule.
The Effects of Vitamin D Deficiency on Histomorphometry and Strength of Rat Vertebrae
Authors: Chou Kathy , Kim Grace , van der Meulen Marjolein C. H.
Published: June 2018

Vitamin D3 is integral to both bone remodeling and calcium homeostasis [1]. With vitamin D deficiency, rickets develops during growth and osteomalacia results in adulthood [2]; in both cases, mineralization is altered and bones are more prone to fracture. Although the degenerative effects of vitamin D deficiency on trabecular architecture have been studied, investigations examining both compromised tissue material properties and mechanical properties in the vertebrae of growing animals are scarce. Therefore, the objective of this study was to investigate cancellous bone architecture and mechanical property changes caused by altered mineralization through vitamin D deficiency in growing rats.
Developing Population-Specific Predictive Regression Equations for Body Segment Parameters
Authors: Sukits Alison L. , Chambers April J. , Perera Subashan , Cham Rakié
Published: June 2018

With an increase in the older adult population aged 65 and over in the United States, there has also been an increase in the incidence of injury amongst this age group. In 2003, injury was the sixth leading cause of death in adults aged 65–74 and seventh in adults aged 75–84 [1,2]. Additionally, the cost of non-fatal injuries doubled from ages 65–74 to ages 75–84, showing not only a potential for increased injury risk in older adults, but also an increase in economic burden with age [1,3]. However, age is just one factor contributing to the increased injury risk. Obesity has also been shown to impact injury risk [4,5]. Research has shown that overweight adults over the age of 65 have a greater risk for impaired physical function and injury [4,5].
Contrast-Enhanced Computed Tomography for Non-Destructive, Quantitative Assessment of the Early Stages of Fracture Healing
Authors: De Bakker C. M. J. , Hayward L. N. M. , Gerstenfeld L. C. , Grinstaff M. W. , Morgan E. F.
Published: June 2018

Each year in the United States, approximately 600,000 bone fractures show delayed or impaired healing and require subsequent surgical intervention1. Techniques for early identification of these cases are presently lacking but could make substantial impact on reducing the morbidity and costs associated with poor bone healing. A current barrier to early assessment of fracture healing is the difficulty in visualizing the cartilaginous “soft” callus that forms at the fracture site in the early stages of repair. The soft callus serves to partially stabilize the fracture and provides a template for subsequent formation of the bony “hard” callus2. Although measurement or estimation of the size, stiffness, and strength of the hard callus is possible by x-ray or computed tomography (CT)3, no analogous methods have been developed for the soft callus, due to the low radio-opacity of cartilage.
Effects of Composite Substrate Microstructure on Fibroblast Morphology and Migration
Authors: Chang Wei-Jen , Chahine Nadeen , Chao Pen-Hsiu Grace
Published: June 2018

Many studies have focused on the effects of substrate rigidity on cell traction, migration, and differentiation [1–3]. Most cells are known to migrate toward the stiffer substrate, a phenomenon known as durotaxis. Recent reports have also demonstrated the ‘depth-sensing’ ability of cells on soft hydrogels where cell behaviors on thin gels are more similar to those on stiffer substrates [4–5]. Taking advantage of the high fidelity of microfabrication and soft lithography products, we created novel composite substrates composed of a top layer of collagen hydrogel and an underlying microstructure of silicon elastomer. We hypothesize that cells can sense the underlying microstructures and regulate cell translocation and morphology accordingly.
Development of a Finite Element Lumbar Segment Model for Simulation of Coupled Loading Conditions Validated With In Vitro Experimental Studies
Authors: Li Yuan , Kelly Brian P. , DiAngelo Denis J.
Published: June 2018

The traditional approach for evaluating the biomechanics of the spine, both experimentally and computationally, is through a series of planar loading scenarios that are reduced to sagittal (flexion/extension), frontal (lateral bending), and transverse (axial) planes of movement [1]. However, coupled movements occur through daily living activities that place further demands on a spinal device beyond simple planar movements. The objective of this study was to investigate the in vitro biomechanics of the L4-L5 lumbar motion segment unit (MSU) under the coupled loading conditions, and to use the experimental data to validate a high-fidelity non-parametric finite element (FE) model of the L4-L5 lumbar MSU.
Relationship Between Tibial and Femoral Bone Morphology and Soft Tissue Laxity of the Knee Using a PCA Model
Authors: Cyr Adam , Courtis Patrick , Komosa Mark , Mane Amit , FitzPatrick David , Maletsky Lorin
Published: June 2018

Understanding morphological variations in bone has become an important topic, specifically for total knee arthroplasties (TKA). The need for implants to cater to differences in bone shape has been highly debated [1–2]. Equally important is understanding the relationship between bone shape and kinematic variations. Previous work has investigated the relationship of several anatomical measures on varus-valgus (VV) and internal-external (IE) laxity [3]. However, the relationship between VV and IE laxity is less understood. The first objective of this research was to understand the relationship between IE and VV laxity using a single principal component analysis (PCA) model. The second objective was to correlate the results of the laxity model with a more inclusive measure of shape variation using statistical shape modeling (SSM). The use of SSM allows for quantifications of variation between subjects to be expressed in a manner which provides a more thorough understanding of bone variation [4]. The purpose of this research was to identify the relationship between IE and VV laxity, and correlate those results with variations in bone morphology of the femur and tibia.
Training-Monitoring Engagement: An Evidence-Based Approach in Elite Sport
Authors: Neupert Emma C. , Cotterill Stewart T. , Jobson Simon A.
Published: June 2018

Purpose: Poor athlete buy-in and adherence to training-monitoring systems (TMS) can be problematic in elite sport. This is a significant issue, as failure to record, interpret, and respond appropriately to negative changes in athlete well-being and training status may result in undesirable consequences such as maladaptation and/or underperformance. This study examined the perceptions of elite athletes to their TMS and their primary reasons for noncompletion. Methods: Nine national-team sprint athletes participated in semistructured interviews on their perceptions of their TMS. Interview data were analyzed qualitatively, based on grounded theory, and TMS adherence information was collected. Results: Thematic analysis showed that athletes reported their main reason for poor buy-in to TMS was a lack of feedback on their monitoring data from key staff. Furthermore, training modifications made in response to meaningful changes in monitoring data were sometimes perceived to be disproportionate, resulting in dishonest reporting practices. Conclusions: Perceptions of opaque or unfair decision making on training-program modifications and insufficient feedback were the primary causes for poor athlete TMS adherence. Supporting TMS implementation with a behavioral-change model that targets problem areas could improve buy-in and enable limited resources to be appropriately directed.
A Randomized Controlled Trial Investigating the Feasibility and Adherence to an Aerobic Training Program in Healthy Individuals
Authors: Teel Elizabeth F. , Marshall Stephen W. , Appelbaum L. Gregory , Battaglini Claudio L. , Carneiro Kevin A. , Guskiewicz Kevin M. , Register-Mihalik Johna K. , Mihalik Jason P.
Published: June 2018

Context: Concussion management is moving from passive rest strategies to active interventions, including aerobic exercise therapy. Little information is available regarding the feasibility and adherence of these programs. Objectives: To determine whether an aerobic exercise training program intended for rehabilitation in people with concussion is feasible. Healthy, nonconcussed subjects were studied in this phase 1 trial. Design: Phase 1 parallel-group, randomized controlled trial in a sample of healthy (nonconcussed), recreationally active university students. Setting: Laboratory. Patients: 40 healthy university students. Methods: Participants were equally randomized to acute concussion therapy intervention (ACTIVE) training or nontraining groups. All participants completed maximal cardiopulmonary exercise tests on a stationary cycle ergometer at 2 test sessions approximately 14 days apart. During this 2-week study period, ACTIVE training participants completed six 30-minute cycling sessions, progressing from 60% to 80% of the participant’s individualized maximal oxygen consumption. A subset of participants (NACTIVE = 12, Nnontraining = 11) wore physical activity monitors throughout the 2-week study period. Main Outcomes Measures: Study protocol and randomization effectiveness, exercise safety and adherence, and progressive intensity of the ACTIVE training procedures. Results: No adverse events occurred during any exercise sessions. Twelve ACTIVE training participants (60%) completed all training sessions, and every participant completed at least 4 sessions. Heart rate increased throughout the training period (P < .001), but symptom changes and training adherence remained stable despite the progressively increasing workload. ACTIVE training participants completed approximately 30 additional minutes of physical activity on training sessions days, although that was not statistically significant (P = .20). Conclusions: University-aged students were adherent to the ACTIVE training protocol. Future research should investigate the safety and feasibility of aerobic training programs in acutely concussed individuals to determine their appropriateness as a clinical rehabilitation strategy.
Efficacy of ReBound Diathermy as a Thermal Heating Agent: A Critically Appraised Topic
Authors: Rhode Alissa C. , Lavelle Lauren M. , Berry David C.
Published: June 2018

Clinical Scenario: ReBound is a portable shortwave diathermy unit used to heat tissues using the same principle as induction drum shortwave diathermy. It is unclear if ReBound can vigorously (4°C) heat intramuscular tissue as efficiently as other thermal agents. Clinical Question: In adults (P), is ReBound diathermy (I) compared with other thermal agents (C) effective at increasing intramuscular tissue temperature by 4°C (O)? Summary of Key Findings: (1) Three studies were included for review, all randomized crossover studies. (2) All studies agreed ReBound does not achieve vigorous (4°C) heating effects during a 30-minute treatment to the triceps surae muscle (depth = 1 and 3 cm). (3) Studies agreed that the heat generated by ReBound dissipates slower than (P < .001) or similar to pulsed shortwave diathermy at 3 cm and faster than moist hot packs (P < .001) at 1 cm. (4) One study found that intramuscular tissue temperatures increased more with ReBound (3.69°C [1.50°C]) than moist hot packs (2.82°C [0.90°C]) at superficial depths (1 cm, d = 0.70). (5) Two studies compared ReBound with MegaPulse II pulsed shortwave diathermy at a 3 cm depth. One found that the MegaPulse II increased intramuscular tissue temperature by 4.32°C (1.79°C) compared with the ReBound’s 2.31°C (0.87°C) increase (d = 1.43). The final study reported that the MegaPulse II increased triceps surae muscle temperature by 3.47°C (0.92°C) versus ReBound at 3.08°C (1.19°C) (d = 0.37). (6) The combined results are an increase of 3.81 (1.38°C) for the MegaPulse II and 2.77 (1.12°C) for ReBound (d = 0.83). Clinical Bottom Line: Results strongly indicate that the ReBound should not be used for vigorous (4°C) heating effects in the triceps surae muscle at 1 and 3 cm. Clinicians can use ReBound when traveling or instead of moist hot packs for moderate (2°C–3°C) heating effects at deep and superficial levels (1 and 3 cm) for large treatment areas with subcutaneous fat thickness <15 mm. Strength of Recommendation: Consistent level B findings indicate that ReBound does not achieve vigorous heating effects (4°C).
Hop Stabilization Training Improves Neuromuscular Control in College Basketball Players With Chronic Ankle Instability: A Randomized Controlled Trial
Authors: Minoonejad Hooman , Karimizadeh Ardakani Mohammad , Rajabi Reza , Wikstrom Erik A. , Sharifnezhad Ali
Published: June 2018

Context: Neuromuscular control deficit has been reported in people with chronic ankle instability (CAI) and hopping exercises have been recommended as a functional training tool to prevent lower limb injury, but its effects on lower-extremity neuromuscular control in those with CAI are unclear. Objective: To investigate the effect of hop stabilization training on neuromuscular control and self-reported function in college basketball players with CAI. Study Design: A randomized controlled trial. Setting: Research Laboratory. Patients (or Other Participants): A total of 28 college basketball players with CAI were randomly assigned to the experimental hop stabilization group (age = 22.78 [3.09] y, weight = 82.59 [9.51] kg, and height = 187.96 [7.93] cm) or the control group (age = 22.57 [2.76] y, weight = 78.35 [7.02] kg, and height = 185.69 [7.28] cm). Intervention: Participants in the experimental group performed supervised hop stabilization exercises 3 times per week for 6 weeks. The control group received no intervention. Main Outcome Measures: Preparatory and reactive muscle activation levels and muscle onset time were assessed from 8 lower-extremity muscles during a jump-landing task before and after the 6-week training program. Results: Significant improvements in preparatory muscle activation, reactive muscle activation, and muscle onset time were noted across the lower-extremity in the experimental group relative to the control group (P < .05). Self-reported function also improved in the experimental group relative to the control group (P < .05). Conclusions: These findings demonstrate that 6 weeks of hop stabilization training is effective in improving neuromuscular control and self-reported function in college basketball players with CAI. Hop stabilization exercises can be incorporated into the rehabilitation program for CAI.
Random number generators go public
Authors: Chen Sophia
Published: June 2018

Free, web-based beacons could be used in commerce, politics, and science
Second Chern number of a quantum-simulated non-Abelian Yang monopole
Authors: Sugawa Seiji , Salces-Carcoba Francisco , Perry Abigail R. , Yue Yuchen , Spielman I. B.
Published: June 2018

Going beyond the first Chern number

Topological properties of physical systems are reflected in so-called Chern numbers: A nonzero Chern number typically means that a system is topologically nontrivial. Sugawa
et al.
engineered a cold atom system with a nonzero second Chern number, in contrast to condensed matter physics, where only the first Chern number is usually invoked. The exotic topology relates to the emergence of a type of magnetic monopole called the Yang monopole (known from theoretical high-energy physics) in a five-dimensional space of internal degrees of freedom in a rubidium Bose-Einstein condensate. The results illustrate the potential of cold atoms physics to simulate high-energy phenomena.

Science
, this issue p.
1429
Emergence of coexisting ordered states in active matter systems
Authors: Huber L. , Suzuki R. , Krüger T. , Frey E. , Bausch A. R.
Published: June 2018

A balance between motion and cooperation

In active matter systems, the infusion of energy and motion drives ordering processes. Huber
et al.
present a combination of experiments and numerical simulations on an active matter system consisting of actin filaments propelled across a surface by surface-attached myosin motor proteins. Adding a depletion agent—polymer chains that weakened interactions between the actin filaments—drove the system between ferromagnetic (polar) and nematic (liquid crystal) ordering.

Science
, this issue p.
255
Heterogeneous to homogeneous melting transition visualized with ultrafast electron diffraction
Authors: Mo M. Z. , Chen Z. , Li R. K. , Dunning M. , Witte B. B. L. , Baldwin J. K. , Fletcher L. B. , Kim J. B. , Ng A. , Redmer R. , Reid A. H. , Shekhar P. , Shen X. Z. , Shen M. , Sokolowski-Tinten K. , Tsui Y. Y. , Wang Y. Q. , Zheng Q. , Wang X. J. , Glenzer S. H.
Published: June 2018

Golden ultrafast melting

Understanding fast melting of metals is important for applications such as welding and micromachining. However, fast melting leaves simulation as the only option for probing the process. Mo
et al.
performed ultrafast electron diffraction experiments on laser-pulsed gold films. This allowed detailed mapping of the melting process, which proceeds through two distinct regimes while the bonding behavior changes in unexpected ways. The results require adding new physical processes to high-energy melting models.

Science
, this issue p.
1451
Cryo-EM structure of a mitochondrial calcium uniporter
Authors: Yoo Jiho , Wu Mengyu , Yin Ying , Herzik Mark A. , Lander Gabriel C. , Lee Seok-Yong
Published: June 2018

A channel for calcium

Maintaining the correct balance of calcium concentrations between the cytosol and the mitochondria is essential for cellular physiology. A calcium-selective channel called the mitochondrial calcium uniporter (MCU) mediates calcium entry into mitochondria. Yoo
et al.
report the high-resolution structure of MCU from
Neurospora crassa.
The channel is formed by four MCU protomers with differing symmetry between the soluble and membrane domains. The structure, together with mutagenesis, suggests that two acidic rings inside the channel provide the selectivity for calcium.

Science
, this issue p.
506
Predictive modeling of U.S. health care spending in late life
Authors: Einav Liran , Finkelstein Amy , Mullainathan Sendhil , Obermeyer Ziad
Published: June 2018

End-of-life health care spending

In the United States, one-quarter of Medicare spending occurs in the last 12 months of life, which is commonly seen as evidence of waste. Einav
et al.
used predictive modeling to reassess this interpretation. From detailed Medicare claims data, the extent to which spending is concentrated not just on those who die, but on those who are expected to die, can be estimated. Most deaths are unpredictable; hence, focusing on end-of-life spending does not necessarily identify “wasteful” spending.

Science
, this issue p.
1462
Two-channel model for ultralow thermal conductivity of crystalline Tl
3
VSe
4
Authors: Mukhopadhyay Saikat , Parker David S. , Sales Brian C. , Puretzky Alexander A. , McGuire Michael A. , Lindsay Lucas
Published: June 2018

Glass-like and crystal-like

Crystals with glass-like ultralow thermal conductivity are appealing as barrier coatings and thermoelectric materials. Mukhopadhyay
et al.
developed a class of thallium selenides with glass-like thermal conductivity. These materials may be promising for applications, but they also require the combination of glass-like and crystal-like thermal transport to explain their thermal properties. This two-channel model can be used to identify potential ultralow-thermal-conductivity compounds.

Science
, this issue p.
1455
Dirac electrons in a dodecagonal graphene quasicrystal
Authors: Ahn Sung Joon , Moon Pilkyung , Kim Tae-Hoon , Kim Hyun-Woo , Shin Ha-Chul , Kim Eun Hye , Cha Hyun Woo , Kahng Se-Jong , Kim Philip , Koshino Mikito , Son Young-Woo , Yang Cheol-Woong , Ahn Joung Real
Published: June 2018

Dirac fermions in quasicrystalline graphene

Quasicrystal lattices, which can have rotational order but lack translational symmetry, can be used to explore electronic properties of materials between crystals and disordered solids. Ahn
et al.
grew graphene bilayers rotated exactly 30° that have 12-fold rotational order. Electron diffraction and microscopy confirmed the formation of quasicrystals, and angle-resolved photoemission spectroscopy revealed anomalous interlayer electronic coupling that was quasi-periodic. The millimeter-scale layers can potentially be transferred to other substrates.

Science
, this issue p.
782
A method for single-neuron chronic recording from the retina in awake mice
Authors: Hong Guosong , Fu Tian-Ming , Qiao Mu , Viveros Robert D. , Yang Xiao , Zhou Tao , Lee Jung Min , Park Hong-Gyu , Sanes Joshua R. , Lieber Charles M.
Published: June 2018

Eye can see neural activity

Organisms take up a tremendous amount of information through the visual system, which is then processed by the neural circuitry. Hong
et al.
developed a mesh electronics implant that is delivered by injection into mice retinas. With these devices, it is possible to obtain recordings from retinal ganglion cells over long time periods in awake, active mice. Both orientation- and direction-selective retinal ganglion cells can be monitored, as can the circadian modulation of retinal ganglion cell activity.

Science
, this issue p.
1447
Toward a sustainable materials system
Authors: Olivetti Elsa A. , Cullen Jonathan M.
Published: June 2018

An unprecedented effort is needed to achieve sustainable materials production and use
Bacterial Production of Gellan Gum as a Do-It-Yourself Alternative to Agar
Authors: McGuffey Jenna C. , Leon Dacia , Dhanji Erum Z. , Mishler Dennis M. , Barrick Jeffrey E.
Published: June 2018

Lack of access to reagents and equipment can make performing microbiology experiments difficult in K-12 classrooms and do-it-yourself (DIY) science settings. We demonstrate how the bacterium Sphingomonas paucimobilis can be used to synthesize gellan gum, an alternative to agar, with materials available to DIY scientists and educators. The method involves microwaving cultures of S. paucimobilis after a two-step growth procedure, supplementing them with additional media components as necessary, and then pouring plates. Gellan gum produced in the S. paucimobilis culture acts as a solidifying agent and provides a resilient surface that supports growth of microbes, including Escherichia coli and Saccharomyces cerevisiae. This procedure offers a unique opportunity to experiment with microbial production of an extracellular polysaccharide and to cheaply and sustainably source a reagent for research.
Modified Anoikis Assay That Functionally Segregates Epstein-Barr Virus LMP1 Strains into Two Groups
Authors: Wasil Laura R. , Shair Kathy H. Y.
Published: June 2018

LMP1 is one of the most divergent sequences in the EBV genome and phylogenetically segregates into seven LMP1 strains. The LMP1 strains differ in geographical distribution and NPC tumor prevalence, but the molecular basis for this potential selection is not clear. While there are signaling motifs conserved in all LMP1 sequences from circulating EBV isolates, phylogenetic studies of NPC also suggest that there may be sequence selection for tumor-associated LMP1 strains and polymorphisms. The present study describes a modified anoikis assay that can distinguish LMP1 strains into two groups by biological properties. The pleiotropic LMP1 signaling properties and sequence diversity may offer a unique opportunity to illuminate the complex mechanisms of metastasis. Although the host genomic landscape is variable between NPC tumors, the present functional-mapping studies on LMP1 support the notion that viral proteins could serve as molecular tool kits and potentially reveal sequence-associated risk factors in NPC metastatic progression.
Geminivirus Replication Protein Impairs SUMO Conjugation of Proliferating Cellular Nuclear Antigen at Two Acceptor Sites
Authors: Arroyo-Mateos Manuel , Sabarit Blanca , Maio Francesca , Sánchez-Durán Miguel A. , Rosas-Díaz Tabata , Prins Marcel , Ruiz-Albert Javier , Luna Ana P. , van den Burg Harrold A. , Bejarano Eduardo R.
Published: June 2018

SUMO adducts have a key role in regulating the activity of animal and yeast PCNA on DNA repair and replication. Our work demonstrates for the first time that sumoylation of plant PCNA occurs in plant cells and that a plant virus interferes with this modification. This work marks the importance of sumoylation in allowing viral infection and replication in plants. Moreover, it constitutes a prime example of how viral proteins interfere with posttranslational modifications of selected host factors to create a proper environment for infection.
Herpes Simplex Virus 2 Latency-Associated Transcript (LAT) Region Mutations Do Not Identify a Role for LAT-Associated MicroRNAs in Viral Reactivation in Guinea Pig Genital Models
Authors: Kawamura Yoshiki , Bosch-Marce Marta , Tang Shuang , Patel Amita , Krause Philip R.
Published: June 2018

Despite the long-standing observation that herpes simplex virus (HSV) latency-associated transcript (LAT) promoter deletion viruses show impaired recurrence phenotypes in relevant animal models, the mechanism by which these sequences exert this phenotypic effect is unknown. We constructed and evaluated four mutant HSV-2 isolates with targeted mutations in the LAT promoter and LAT-associated microRNAs (miRNAs) affecting (i) the LAT TATA box; (ii) the LAT ICP4-binding site; (iii) miRNA I (miR-I) and miR-II (miR-I/II), which both target ICP34.5; and (iv) miR-III, which targets ICP0. While the LAT TATA box mutant caused milder acute infections than wild-type (WT) virus, there was no difference in the recurrence phenotype between these viruses. LAT and miRNA expression during latency was not impaired by this mutation, suggesting that other promoter elements may be more important for latent HSV-2 LAT expression. Mutation of the LAT ICP4-binding site also did not cause an
in vivo
phenotypic difference between mutant and WT viruses. Acute infection and reactivation from latency of the miR-I/II mutant were similar to those of its rescuant, although the acute infection was slightly reduced in severity relative to that caused by the wild-type virus. The miR-III mutant also exhibited WT phenotypes in acute and recurrent phases of infection. While they do not rule out an effect of these elements in human latency or reactivation, these findings do not identify a specific role for LAT or LAT-associated miRNAs in the HSV-2 LAT promoter deletion phenotype in guinea pigs. Thus, other sequences in this region may play a more important role in the long-studied LAT-associated phenotype in animals.

IMPORTANCE
While it has been known for several decades that specific HSV-1 and HSV-2 sequences near the LAT promoter are required for efficient viral reactivation in animal models, the mechanism is still not known. We constructed four mutant viruses with the goal of identifying critical sequence elements and of specifically testing the hypothesis that microRNAs that are expressed during latency play a role. Determination that specific LAT promoter sequences and miRNA sequences do not influence viral reactivation of HSV-2 helps to narrow down the search for the mechanism by which the virus controls its latency and recurrence phenotype.
A Novel Nanobody Targeting Middle East Respiratory Syndrome Coronavirus (MERS-CoV) Receptor-Binding Domain Has Potent Cross-Neutralizing Activity and Protective Efficacy against MERS-CoV
Authors: Zhao Guangyu , He Lei , Sun Shihui , Qiu Hongjie , Tai Wanbo , Chen Jiawei , Li Jiangfan , Chen Yuehong , Guo Yan , Wang Yufei , Shang Jian , Ji Kaiyuan , Fan Ruiwen , Du Enqi , Jiang Shibo , Li Fang , Du Lanying , Zhou Yusen
Published: June 2018

Therapeutic development is critical for preventing and treating continual MERS-CoV infections in humans and camels. Because of their small size, nanobodies (Nbs) have advantages as antiviral therapeutics (e.g., high expression yield and robustness for storage and transportation) and also potential limitations (e.g., low antigen-binding affinity and fast renal clearance). Here, we have developed novel Nbs that specifically target the receptor-binding domain (RBD) of MERS-CoV spike protein. They bind to a conserved site on MERS-CoV RBD with high affinity, blocking RBD's binding to MERS-CoV receptor. Through engineering a C-terminal human Fc tag, the
in vivo
half-life of the Nbs is significantly extended. Moreover, the Nbs can potently cross-neutralize the infections of diverse MERS-CoV strains isolated from humans and camels. The Fc-tagged Nb also completely protects humanized mice from lethal MERS-CoV challenge. Taken together, our study has discovered novel Nbs that hold promise as potent, cost-effective, and broad-spectrum anti-MERS-CoV therapeutic agents.
Prevalence and clinical consequences of cytomegalovirus DNA in the aqueous humour and corneal transplants
Authors: Hsiao Ching-Hsi , Hwang Yih-Shiou , Chuang Wen-Yu , Ma David H K , Yeh Lung-Kun , Chen Shin-Yi , Shu Jwu-Ching
Published: June 2018

Aim

To determine the prevalence and clinical consequences of cytomegalovirus (CMV) DNA in the aqueous and corneal tissues obtained at the time of corneal transplantation to evaluate the diagnostic value of PCR analysis in identifying patients at risk of postkeratoplasty CMV endotheliitis.

Methods

Thirty patients who underwent corneal transplantation were included in 2011. The aqueous, excised recipient corneas and donor corneoscleral rims were analysed by PCR for the presence of CMV DNA. The medical records of the patients were retrospectively reviewed and linked with PCR results.

Results

CMV DNA was detected in three (10%) aqueous, eight (26.7%) recipient corneas and six (20.0%) donor corneas obtained during keratoplasty from the 30 patients. Postoperatively, four patients, who had CMV DNA in either aqueous (3) or recipient cornea (1), were diagnosed with CMV endotheliitis based on clinical features and repeat aqueous tapping for real-time PCR analysis. At the median 60.5 months follow-up, 8 (72.7%), including 4 with postkeratoplasty CMV endotheliitis, of the 11 patients with CMV positivity in any one sample had graft failure, while 9 (47.3%) of the 19 patients without evidence of CMV DNA experienced graft failure.

Conclusions

We found a relatively high prevalence of CMV DNA in the aqueous and corneas obtained during keratoplasty. All the patients who had CMV positivity in aqueous developed CMV endotheliitis postoperatively and experienced graft failure eventually. Aqueous tapping at the time of corneal transplantation for PCR analysis may help to improve the diagnosis and follow-up management of postkeratoplasty CMV endotheliitis.
Quantitative retinal microvasculature in children using swept-source optical coherence tomography: the Hong Kong Children Eye Study
Authors: Cheung Carol Y , Li Jian , Yuan Nan , Lau Gordon Yiu Leung , Chan Anthony Yu Fung , Lam Alexander , Tang Fang Yao , Tham Clement C , Pang Chi-Pui , Chen Li Jia , Yam Jason C
Published: June 2018

Aims

To evaluate the distributions of quantitative optical coherence tomography angiography (OCT-A) metrics and its associated factors in children.

Methods

1059 children aged 6–8 years were recruited from the Hong Kong Children Eye Study. All the participants underwent OCT-A with a swept-source OCT. Retinal microvasculature on superficial capillary plexus was assessed and quantified by a customised automated image analysis programme. Univariable and multiple linear regression analyses were performed to determine systemic (body mass index (BMI), waist circumference, head circumference and blood pressure), demographic and ocular (axial length (AL), macular thickness and volume, retinal nerve fibre layer (RNFL) thickness and visual acuity) variables (independent variables) associated with OCT-A metrics (dependent variables).

Results

In multiple linear regression analyses, enlarged foveal avascular zone area was associated with female gender (β=0.110, p<0.001), decreased AL (β=−0.097, p<0.001) and decreased central macular thickness (β=−0.008, p<0.001). Decreased vessel density was associated with increased BMI (β=−4.12×10−4, p=0.006), decreased AL (β=0.003, p<0.001) and decreased central macular thickness (β=7.87×10−5, p=0.001). Increased vessel diameter index was associated with female gender (β=0.020, p=0.007) and decreased AL (β=−0.020, p<0.001). Decreased fractal dimension was associated with older age (β=−0.001, p=0.008). There were no significant correlations between OCT-A metrics with visual acuity, RNFL thickness, central corneal thickness, waist circumference, head circumference and blood pressure (all p>0.05).

Conclusion

Our findings provides new information on baseline morphology of retinal microvasculature and its associated factors in school children, which will be useful for interpreting OCT-A metrics and for identifying and characterising pathological changes in retinal microvasculature.
Sexual health prevention for incarcerated women: eroticising safe sex during re-entry to the community
Authors: Kuo Caroline C , Rosen Rochelle K , Zlotnick Caron , Wechsberg Wendee M , Peabody Marlanea , Johnson Jennifer E
Published: June 2018

Introduction

In the USA, incarcerated women are disproportionately affected by sexually transmitted infections (STIs) including HIV. Transitioning from incarceration into the community is accompanied by elevated risk behaviours related to acquisition of STIs, yet few efficacious interventions address sexual health prevention among incarcerated women.

Methods

We conducted an exploratory qualitative study with 21 incarcerated women at four women’s state prison facilities in two Northeastern states in the USA. Qualitative data were gathered from four focus groups to guide future intervention development. Focus group discussions were guided by a semi-structured protocol exploring perceptions of sexual health prevention methods, experience with implementing prevention technologies and protective behaviours, and strategies to overcome challenges in implementing sexual health prevention behaviours. Focus groups were audio-recorded and transcribed verbatim. Data were analysed using thematic analysis.

Results

Women described challenges in uptake of existing low-cost sexual health prevention strategies such as condoms. They identified strategies to facilitate use of prevention tools, and to increase protective behaviours relating to sexual health during the transition from incarceration to the community. For example, women described methods for eroticising male and female condoms, including selecting condoms with novel features, explaining to partners that condoms could increase sexual pleasure, and incorporating condom application into foreplay and/or oral sex.

Conclusion

Incorporating these insights, including how to eroticise safe sex, can inform the design of future preventive interventions tailored to meet the urgent sexual health needs of incarcerated women preparing for reintegration into the community.

Clinical trial registration

NCT01907126.
A 42-year-old woman with acute myocardial infarction
Authors: Fahey James K , Ihdayhid Abdul Rahman , White Anthony John
Published: June 2018

Clinical introduction

A 42-year-old woman presented with anterior ST elevation myocardial infarction. Urgent coronary angiography revealed tapering then occlusion of the distal left anterior descending (LAD) coronary artery with no flow in the distal LAD (figure 1A). Balloon angioplasty with a 2.0×8 mm balloon re-established flow into the distal LAD. An angiogram of the right external iliac artery was also performed (figure 1B).

Figure 1

Invasive angiography of the left coronary system (A) and the right external iliac artery (B). The coronary angiogram (A) shows tapering and then occlusion (arrow) of the distal left anterior descending coronary artery.

Question

Which of the following explains the abnormal appearance of the external iliac artery (figure 1B)?

Atherosclerosis.

Concertina effect.

Fibromuscular dysplasia.

Perforation.

Multiple aneurysms.
Models for predicting risk of dementia: a systematic review
Authors: Hou Xiao-He , Feng Lei , Zhang Can , Cao Xi-Peng , Tan Lan , Yu Jin-Tai
Published: June 2018

Background

Information from well-established dementia risk models can guide targeted intervention to prevent dementia, in addition to the main purpose of quantifying the probability of developing dementia in the future.

Methods

We conducted a systematic review of published studies on existing dementia risk models. The models were assessed by sensitivity, specificity and area under the curve (AUC) from receiver operating characteristic analysis.

Results

Of 8462 studies reviewed, 61 articles describing dementia risk models were identified, with the majority of the articles modelling late life risk (n=39), followed by those modelling prediction of mild cognitive impairment to Alzheimer’s disease (n=15), mid-life risk (n=4) and patients with diabetes (n=3). Age, sex, education, Mini Mental State Examination, the Consortium to Establish a Registry for Alzheimer’s Disease neuropsychological assessment battery, Alzheimer’s Disease Assessment Scale-cognitive subscale, body mass index, alcohol intake and genetic variables are the most common predictors included in the models. Most risk models had moderate-to-high predictive ability (AUC>0.70). The highest AUC value (0.932) was produced from a risk model developed for patients with mild cognitive impairment.

Conclusion

The predictive ability of existing dementia risk models is acceptable. Population-specific dementia risk models are necessary for populations and subpopulations with different characteristics.