bluuebunny/crossref_metadata_2025 huggingface dataset:
VP08 Can Health-Economic Evaluation Provide a Representation of ‘Value For Money’ For HTA?
Authors: Booth Neill
Published: December 2019

Introduction

Health technology assessment (HTA) processes typically combine both evidence and values in order to inform decisions about relative value. Health-economic evaluation and other economic evidence are thought by many to be important for such processes, but there is typically tension between the information offered by health-economic assessment, and the context-specific interpretation of such information. This study reviews the meaning, and interpretation, of ‘health-economic evaluation’ aimed at informing HTA processes. One central aim is to answer the question: “Can health-economic evaluation provide a representation of ‘value for money’ for HTA?”

Methods

A seminal article was used as a starting point and then a variety of search techniques, including bi-directional citation searching, were used to obtain evidence relating to the study objective. A critical review is undertaken spanning the last fifty years of health-economic evaluation, which provides perspective on the balance between more context-independent assessments and the context-specific interpretation of those assessments.

Results

Although health-economic evaluation can legitimately be undertaken in a variety of ways, we find that processes of ‘valuation’ are fundamental to all approaches to economic evaluation in practice. Values influence how these economic value frameworks tend to be operationalized, promoted and understood. Our critical review provides those interested in prioritization with a timely reminder that health-economic evaluation should be thought of as largely context- and content -specific.

Conclusions

Health-economic evaluation can typically only offer a truncated representation of ‘value for money’ to HTA processes. In answer to the question posed above, this study finds that health-economic evaluation will typically not provide a full assessment of ‘value for money’. Therefore, it should always be accompanied by an assessment of its qualities: what is covered in the analysis, how well what is covered is measured or analysed, and what is left out. Humility about what health-economic evaluation can offer would seem useful, especially given that other elements of value exist, such as the potential harms and benefits of medical-industry profits and environmental sustainability.
VP11 Use Of Health Technology Assessment Adaptation In Latin America
Authors: Irisarri Magdalena , Pintos Javier , Deminco Ana , Pedrosa Daniel , Aleman Alicia , Galán Ana Perez
Published: December 2019

Introduction

The development of health technology assessment (HTA) reports is a time-consuming process that requires highly trained human resources. In many Latin American countries this type of personnel is scarce. The adaptation of HTA could be a time-saving process to get inputs for decision. The objective of this study is to determine the frequency of use of HTA adaptation process and to describe type of tools used in this process in Latin American countries.

Methods

The Health Technology Assessment Network of the Americas (REDETSA) is a non-profit network formed by ministries of health, regulatory authorities and health technology assessment agencies (PAHO/WHO). During the last meeting of REDETSA in November 2018, we performed an exploration survey to gather information related to the topic in order to promote the creation of an adaptation working group. The question was whether HTA agencies did adaptation of HTA reports and, if so, what methods and tools were used and what sections of the report were adapted.

Results

Thirty-three institutions from fourteen Latin American countries answered to the consultation. Seven countries do adaptation of HTA (50 percent) and one country does adoption. Of those countries that adapt HTA, three do only economic transferability. Methods and tools are usually developed locally or there is not a systematic approach. In two countries, the economic study transferability tool developed by Hutter and Antoñaza is used.

Conclusions

Adaptation of HTA is not well developed among Latin American agencies, although it seems to be an efficient strategy when assessing efficacy and safety. Adaptation of economic studies is still controversial; nevertheless, it is used in some of the countries of the region. It is necessary to advance in the development of HTA adaptation tools, developed and adapted to local contexts in the region.
VP13 Transferability Instrument Of Health Economic Evaluations For Chile
Authors: Hurtado-Meneses Victoria , De la Puente Catherine , Castillo Marianela , Poblete Sergio
Published: December 2019

Introduction

Any technology submission for the high-cost treatment fund in Chile requires an economic evaluation; however, this is time consuming and given its high number, it is not possible to inform decisions within the established period of time. This presentation proposes a guide for the transferability of international economic evaluation results to our national context, with the intention to inform decision makers in a brief period of time.

Methods

A literature review on transferability analysis, tools and instruments to perform transferability analysis and on how to assess quality of economic evaluations was conducted. In addition, a workshop was held to discuss the proposal with other relevant researchers, in order to receive feedback.

Results

The proposed instrument is based on Welte and consists of: (i) a research question is formulated and a systematic review of economic evaluations is conducted, (ii) the three Welte knock-out criteria are applied to these results and, if these are met, the articles pass to the next stage, (iii) a scored comparison based on twelve criteria is conducted on the articles and each article is compared against the Chilean (economic) reference case, (iv) high-scored economic evaluations will be grouped according of their incremental cost-effectiveness ratio (ICER). If all ICERs do not converge, to the same conclusion, the intervention would not be transferable. If the ICERs of these studies converge, then the results will be compared against the national threshold. If the ICERs are greater than the threshold, the intervention would not be cost-effective. If the ICERs are lower than the threshold, then the intervention would be cost-effective in Chile.

Conclusions

Despite a de novo analysis still being the gold standard to inform decision makers, the proposed instrument could be used as an alternative, given the short time limit and the scarcity of qualified human resources.
VP96 Activities To Optimize Quality And Efficiency Of Medicines In Scotland
Authors: Godman Brian , Kurdi Amanj , McCabe Holly , MacBride-Stewart Sean , Johnson Chris , Hurding Simon , Bennie Marion , Morton Alec
Published: December 2019

Introduction

The growing prevalence of non-communicable diseases, combined with greater recognition of the effectiveness of lipid lowering agents (LLAs), has fuelled their increasing use in recent years. Similarly, increasing recognition of mental health and, arguably, societal expectations and pressures, has driven appreciable growth in antidepressant prescribing in recent years. Concurrent with this, growing resource pressures enhanced by the continual launch of new premium priced medicines necessitates reforms and initiatives within finite budgets. Scotland has introduced multiple measures in recent years to improve both the quality and efficiency of prescribing. There is a need to document these initiatives and outcomes to provide future direction.

Methods

Assessment of the utilization (items dispensed) and expenditure of key LLAs (mainly statins) and SSRIs between 2001 and 2017 in Scotland alongside initiatives.

Results

Multiple interventions have increased international non-proprietary name (INN) prescribing (99% for statins and up to 99.9% for SSRIs). They have also increased preferential prescribing of generic versus patented statins with low costs for generics, reduced inappropriate prescribing of ezetimibe due to effectiveness concerns, and increased the prescribing of higher dose statins (71% in 2015). These measures have resulted in a 50% reduction in LLA expenditure between 2001 and 2015 despite a 412% increase in utilization. Initiatives to reduce the prescribing of escitalopram as lack of evidence demonstrating cost-benefits over generic citalopram, along with high INN prescribing, achieved a 73.7% reduction in SSRI expenditure between 2001 and 2017 despite a 2.34-fold increase in utilisation. Concerns with paroxetine, and more recently citalopram and escitalopram following safety warnings, resulted in a considerable reduction in their use alongside a significant increase in sertraline.

Conclusions

Generic availability coupled with multiple measures has resulted in appreciable shifts in statin and SSRI prescribing behavior and reduced ezetimibe prescribing, resulting in improvements in both the quality and efficiency of prescribing to provide future direction.
VP98 Horizon Scanning For New Alternatives To The Treatment Of Leishmaniasis
Authors: Girardi Juliana , Marinho Daniel , Elias Flavia
Published: December 2019

Introduction

The usual treatment of American Cutaneous Leishmaniasis is based on intravenous drugs of the 1940s and causes adverse events, having as first choice pentavalent antimonials that require clinical and laboratory follow-up in the hospital setting. The present study aimed to identify potentially more effective and safe oral therapies, applying Technological Horizon Scanning.

Methods

The searches were divided into three blocks: clinical trials through the Clinical Trials Registry Platform on the WHO search portal; searches in the PubMed, Embase, Cochrane Library, Lilacs and Center for Reviews and Dissemination databases; and search for patents in the Orbit base. The searches aimed at identifying drugs, authors, institutions and therapeutic classes in order to proceed with scanning process.

Results

We found 197 studies and selected 33 in the Americas region. Of these, seventeen (51%) investigated miltefosine, six (18%) had azithromycin, four (12%) Fluconazole, two (6%) pentoxifylline, two (6%) allopurinol and one (3%) terbinafine. Of the 26 clinical studies, twelve presented positive results for oral medications, six related to miltefosine, two to fluconazole, two to pentoxifylline, one to azithromycin and one to allopurinol. Through the analysis of patents, 35 documents involving 32 institutions and 134 inventors were identified. Of the 32 institutions that registered patent documents, Novartis is the one with the highest number of inventors.

Conclusions

Miltefosine is in the incorporation phase in the Brazilian health system, evaluating its performance and effectiveness in the services. Pentoxifylline was recently incorporated as a coadjuvant to the treatment, and Fluconazole presented positive results, however with a small number of patients and uncertain outcomes. It is recommended to carry out more research directed to the drug association, since the studies indicate the possibility of decreasing occurrence of relapses, dosages and treatment time, increasing adherence to treatment.
R v Dudley and Stephens: Degeneration, the Christian Mindset and Judicial Reasoning
Authors: Woolrich Malcolm
Published: December 2019

This article examines how Lord Coleridge's Victorian experiences and Christian mindset played a prominent and persuasive role in the formulation of his judgment in R v Dudley and Stephens. Notwithstanding efforts to act impartially and objectively, we are all beholden, often unconsciously, to the biases and beliefs permeating the society in which we live. Coleridge was no exception, being a composite of influences: family and educational backgrounds, religious beliefs, personal encounters and societal norms. These prejudices sharpen into focus with the benefit of distant hindsight. An associated challenge is the present difficulty faced when interpreting old judgments in which allusions are made to concepts that no longer resonate in the modern world. Finally, we are left to ponder our own predicament: what are the biases that present-day jurists unconsciously possess, how do they influence the formulation of judgments and how will they be understood in a future age?
Plume ‐Tree Structure Induced by Low‐Viscosity Layers in the Upper Mantle
Authors: Liu Hao , Leng Wei
Published: December 2019

Previous seismological results and geodynamic modeling showed that mantle plumes have thin tails. However, the latest geophysical observations reveal the presence of broad and bifurcate plumes in the lower and upper mantle, providing a new challenge to further understand the evolution of plume morphology. Here, developing 3‐D numerical models, we demonstrate that a plume shaped like a tree, derived from the mantle transition zone, branches up to surface volcanoes due to the combined influence of weak layers in the asthenosphere and the mantle transition zone. Clusters of mantle plumes likely explain the simultaneous occurrence of multiple subparallel hot spot tracks in the Pacific and Atlantic Oceans. Meanwhile, the mantle plume wandering at a rate of ~1.5 cm/year in the upper mantle without a strong mantle wind provides a new mechanism for hot spot motions. Thus, our model represents a significant advance for linking plume studies in seismology, geochemistry, and plate reconstruction.
Predicting the flow stress and dominant yielding mechanisms: analytical models based on discrete dislocation plasticity
Authors: Hu Jianqiao , Song Hengxu , Liu Zhanli , Zhuang Zhuo , Liu Xiaoming , Sandfeld Stefan
Published: December 2019

Dislocations are the carriers of plasticity in crystalline materials. Their collective interaction behavior is dependent on the strain rate and sample size. In small specimens, details of the nucleation process are of particular importance. In the present work, discrete dislocation dynamics (DDD) simulations are performed to investigate the dominant yielding mechanisms in single crystalline copper pillars with diameters ranging from 100 to 800 nm. Based on our simulations with different strain rates and sample size, we observe a transition of the relevant nucleation mechanism from “dislocation multiplication” to “surface nucleation”. Two physics-based analytical models are established to quantitatively predict this transition, showing a good agreement for different strain rates with our DDD simulation data and with available experimental data. Therefore, the proposed analytical models help to understand the interplay between different physical parameters and nucleation mechanisms and are well suitable to estimate the material strength for different material properties and under given loading conditions.
Therapeutic effects of statins against lung adenocarcinoma via p53 mutant-mediated apoptosis
Authors: Chou Cheng-Wei , Lin Ching-Heng , Hsiao Tzu-Hung , Lo Chia-Chien , Hsieh Chih-Ying , Huang Cheng-Chung , Sher Yuh-Pyng
Published: December 2019

The p53 gene is an important tumour suppressor gene. Mutant p53 genes account for about half of all lung cancer cases. There is increasing evidence for the anti-tumour effects of statins via inhibition of the mevalonate pathway. We retrospectively investigated the correlation between statin use and lung cancer prognosis using the Taiwanese National Health Insurance Research Database, mainly focusing on early-stage lung cancer. This study reports the protective effects of statin use in early-stage lung cancer patients regardless of chemotherapy. Statin treatments reduced the 5-year mortality (odds ratio, 0.43; P < 0.001) in this population-based study. Significantly higher levels of cellular apoptosis, inhibited cell growth, and regulated lipid raft content were observed in mutant p53 lung cancer cells treated with simvastatin. Further, simvastatin increased the caspase-dependent apoptotic pathway, promotes mutant p53 protein degradation, and decreased motile activity in lung cancer cells with p53 missense mutations. These data suggest that statin use in selected lung cancer patients may have clinical benefits.
Optogenetic stimulation of the VTA modulates a frequency-specific gain of thalamocortical inputs in infragranular layers of the auditory cortex
Authors: Brunk Michael G. K. , Deane Katrina E. , Kisse Martin , Deliano Matthias , Vieweg Silvia , Ohl Frank W. , Lippert Michael T. , Happel Max F. K.
Published: December 2019

Reward associations during auditory learning induce cortical plasticity in the primary auditory cortex. A prominent source of such influence is the ventral tegmental area (VTA), which conveys a dopaminergic teaching signal to the primary auditory cortex. Yet, it is unknown, how the VTA influences cortical frequency processing and spectral integration. Therefore, we investigated the temporal effects of direct optogenetic stimulation of the VTA onto spectral integration in the auditory cortex on a synaptic circuit level by current-source-density analysis in anesthetized Mongolian gerbils. While auditory lemniscal input predominantly terminates in the granular input layers III/IV, we found that VTA-mediated modulation of spectral processing is relayed by a different circuit, namely enhanced thalamic inputs to the infragranular layers Vb/VIa. Activation of this circuit yields a frequency-specific gain amplification of local sensory input and enhances corticocortical information transfer, especially in supragranular layers I/II. This effects persisted over more than 30 minutes after VTA stimulation. Altogether, we demonstrate that the VTA exhibits a long-lasting influence on sensory cortical processing via infragranular layers transcending the signaling of a mere reward-prediction error. We thereby demonstrate a cellular and circuit substrate for the influence of reinforcement-evaluating brain systems on sensory processing in the auditory cortex.
Optimizing the role of impact ionization in conventional insulators
Authors: Manousakis Efstratios
Published: December 2019

A mechanism for multiple carrier generation through impact ionization (IA) proposed earlier for bulk systems of strongly correlated insulators is generalized to the case of conventional insulators that contain localized bands a few eV above and below the highest occupied band. Specifically, we study the case of hybridization of localized orbitals with more dispersive bands near the Fermi level, where the generated multiple carriers, which ultimately decay to the edges of the dispersive bands by means of IA processes, acquire lighter mass and this could allow their more efficient separation before recombination. We argue that this may be applicable to the case of halide perovskites and it could be one of the reasons for their observed photovoltaic efficiency. We discuss the criteria one should use to uncover the appropriate material in order to harvest the optimum effect of IA for the spectrum of the solar photon energy distribution.
Insight into the active site and reaction mechanism for selective oxidation of methane to methanol using H2O2 on a Rh1/ZrO2 catalyst
Authors: Zhao Qi , Liu Bing , Xu Yuebing , Jiang Feng , Liu Xiaohao
Published: December 2019

Five-coordinated Rh leads to the over-oxidation of CH4, while four-coordinated Rh stabilizes CH3 and facilitates methanol formation via the CH3OOH intermediate.
Fluorescence and Opalescence of Two Dental Composite Resins
Authors: Tabatabaei Masoomeh Hasani , Nahavandi Alireza Mahmoudi , Khorshidi Sotude , Hashemikamangar Sedighe Sadat
Published: December 2019

Objective Lifelike esthetic appearance of dental restorations is among the main goals in restorative dentistry. This study aimed to assess and compare the opalescence and fluorescence of two dental composite resins.

Materials and Methods This in vitro experimental study evaluated the A2 shade of Filtek Z350 XT Enamel, Filtek Z350 XT Dentin, Aelite Aesthetic Enamel, and Aelite All Purpose Body composite resins. Composite discs were fabricated with 10 mm diameter and 0.5 and 1 mm thicknesses (n = 2) using a plexiglass mold and subjected to colorimetry. The color parameters were determined according to the International Commission on Illumination (CIE) L*a*b* system using a spectrophotometer. The fluorescence and opalescence were also measured and reported separately for 0.5 and 1 mm thicknesses of Z350, Aelite Body, and Enamel composite resins. To determine the opalescence, the color of samples in the reflectance mode was measured using a calibration cylinder and in the transmittance mode in presence of 100% ultraviolet (UV) light. To determine the fluorescence, the color of samples against a white background in the reflectance mode in presence or absence of 100% UV light was measured.

Statistical Analysis Data were analyzed using SPSS via three-way analysis of variance and independent t-test.

Results The fluorescence of 0.5 mm thickness of all composites was higher than that of 1 mm thickness (p < 0.05). The fluorescence of Aelite was higher than that of Z350 (p < 0.05). The fluorescence of Aelite Enamel was higher than that of Aelite Body irrespective of their thickness, but the results were opposite for Z350 (p < 0.05). In Aelite composite, opalescence increased by an increase in thickness (p < 0.05). The opalescence of Aelite was significantly higher than that of Z350 (p < 0.05). The opalescence of 0.5 mm thickness of Aelite Enamel was higher than that of Aelite Body, while the opalescence of 1 mm thickness of Z350 Body was higher than that of Z350 Enamel (p < 0.05).

Conclusion Thickness, type, and brand of composite resins affected their fluorescence and opalescence.
A Survey of Common Payment Methods and Their Determinants in Dental Clinics, in Tehran, 2018
Authors: Emrani Reza , Sargeran Katayoun , Grytten Justein , Hessari Hossein
Published: December 2019

Objective It is believed that the payment method to dentists may affect their treatment decisions. Although payment systems may enhance job satisfaction, reduce the costs, and make better treatment decisions, there is little information about how to achieve these objectives. The aim of the present study was to survey the payment methods and the related factors in dental clinics of Tehran.

Materials and Methods Using the latest list published by the Iranian Ministry of Health, we visited all dental clinics located in Tehran, and used a checklist to collect the data of the type of management, geographical location of the clinic in Tehran, payment method and its amount, history of payment method changes in the last decade, relationship between the amount of payment and the position of technical supervisor dentist, any difference in the amount of payment to male and female dentists and to young and experienced dentists. Then, the relationship between the amount of payment and the above-mentioned variables was investigated.

Results The governmental sector tends to use fixed salary methods and the private sector usually uses the fee-for-service (FFS) method. Geographical location, type of management, date of establishment, and having the position of technical supervisor dentist had a significant relationship with the amount of payment. The dentist’s gender and years of experience did not have any relationship with the amount of payment.

Conclusion According to the results of the present study, the method and amount of payment to dentists were related to the date of clinic establishment, having the position of technical supervisor dentist, and geographical location of the clinic. These factors could be considered as the main elements in balancing costs in clinics and improving job satisfaction among dentists.
Debris Apically Extruded by Two Reciprocating Systems: A Comparative Quantitative Study
Authors: Amaral Andressa Pinho , Limongi Patrícia Bastos Oliveira Conceição , Fontana Carlos Eduardo , Martin Alexandre Sigrist De , Bueno Carlos Eduardo Da Silveira , Pinheiro Sérgio Luiz
Published: December 2019

Objective The objective of this study was to quantify the amount of debris apically extruded after instrumentation with two reciprocating systems.

Materials and Methods Forty-two single-rooted mandibular premolars with only one straight root canal and apical diameter compatible with a no. 15 K-file were randomly divided into two groups (n = 21) according to the instrument used: ProDesign R (Easy Equipamentos; Belo Horizonte, Minas Gerais, Brazil) and Reciproc Blue (VDW; Munich, Germany). Dry Eppendorf tubes were weighed three consecutive times for the initial mean weight. A silicone stopper was then fitted into the mouth of the tube. Each tooth was inserted through the stopper up to the cementoenamel junction and instrumented with one of the two systems to the predetermined working length (18 mm). The root canals were instrumented per root thirds. At each instrumented root third, the canal was irrigated with 3 mL of double-distilled water, followed by patency control. Each stopper was then separated from the tube and tubes were incubated at 70°C for 5 days. Tubes were again weighed, and the amount of extruded debris was calculated by subtracting the initial mean weight from the final mean weight.

Statistical Analysis Results were analyzed using the Mann–Whitney test at a 5% significance level.

Results No significant difference was observed in debris extrusion between the ProDesign R and Reciproc Blue systems (p = 0.7557).

Conclusions The two reciprocating systems tested produced similar amounts of postinstrumentation apically extruded debris.
Postorthodontic Relapse Prevention by Administration of Grape Seed (Vitis vinifera) Extract Containing Cyanidine in Rats
Authors: Alhasyimi Ananto Ali , Rosyida Niswati Fathmah , Rihadini Mufliha Santi
Published: December 2019

Objective The aim of this study was to analyze the effect of grape seed extract containing cyanidin on osteoclastogenesis (by means of receptor activator of nuclear factor-κ B ligand [RANKL] and osteoprotegerin [OPG] levels) and the number of osteoclasts during orthodontic relapse in Wistar rats.

Materials and Methods This study is an in vivo quasi experimental research. A total of 32 male Wistar rats were used in the study, which were randomly split equally into two groups, grape seed (GS) and control group (CG). All rats were given an orthodontic force of 35 cN using a stainless steel 3-spin coil spring that was activated for 7 days and then conditioned to be passive. During this phase, the GS group was administered grape seed extract containing cyanidin once per day. Orthodontic appliances were removed from both groups afterward, and then the alveolar bone tissue was isolated consecutively according to observation days (days 1, 3, 7, and 14), while OPG and RANKL levels were analyzed in their gingival crevicular fluid using a specific enzyme-linked immunosorbent assay (ELISA). Tissues were then stained with hematoxylin–eosin (H&E) and observed under a light microscope to count the number of osteoclast cells. Data were analyzed statistically using an independent t-test (p < 0.05).

Results The number of osteoclasts in the GS group was significantly lower than that in the CG group on all experiment days (p = 0.021; p = 0.001; p = 0.024; p = 0.001; p < 0.05). ELISA results showed that the RANKL level of the GS group was significantly lower on days 3 and 7 (p = 0.025; p = 0.039; p < 0.05), while the OPG level was significantly higher on days 1 and 3 in the GS group than in the CG group (p = 0.039; p = 0.021; p < 0.05).

Conclusion Grape seed extract can prevent postorthodontic relapse movement by inhibiting osteoclastogenesis and reducing the number of osteoclasts in Wistar rats.
A triarterial arcade - the radial - median - ulnar type of superficial palmar arch
Authors: Bhagyalakshmi Bovindala , Prabha Challa Ratna , Aparna Gullapalli , Chandramohan Madabhushi
Published: December 2019

The most essential prerequisite for hand surgeons is a comprehensive knowledge of variations in the arterial architecture of the hand. There are two well designed arterial arches, superficial palmar arch (SPA) and the deep palmar arch (DPA) situated superficial and deep to flexor tendons and lumbrical muscles respectively. Even though both are formed by the contribution of radial and ulnar arteries, variations are numerous and frequent in SPA that attracts the attention of surgeons. During the routine dissections we found a rare variation in the structural architecture of SPA which was formed by anastomosis of the radial - median and ulnar arteries. This triarterial combination of SPA is an advantage in reconstructive hand surgeries, microvascular surgeries and radial artery harvesting for Coronary artery bypass graft. Presence of incomplete SPA is dangerous to tackle surgically. Screening is essential to know the exact arterial pattern for successful hand surgeries without postoperative complications.
Occipital condyle and its relevance during surgery
Authors: Sinha Manisha B , Trivedi Soumitra , Siddiqui Abu Ubaida , Rathore Mrithunjay
Published: December 2019

Background : Occipital condyle (OC) is an important landmark for transcondylar approach of surgeries in case of lesions ventral to brainstem and craniovertebral junctional anomalies. To go through this approach, one should have an extensive knowledge of occipital condyle. The aim of the current study is to provide linear and angular measurements of OC. Material and methods : The study was performed in 36 dry adult skulls of unknown age and sex. Various morphological and Metric data were collected from specimen. Results : Average length, width and height of the occipital condyle were found to be 22.49mm, 11.87mm, 9.13mm. Intracranial orifices of hypoglossal canal were found to be present against the junction of 2nd and 3rd quarter or against the 3rd quarter of occipital condyle. Extracranial orifices of hypoglossal canal were found to be present against the junction of 1st and 2nd quarter or against the 2rd quarter of occipital condyle. Conclusion : There is no significant racial variation in shape and size of occipital condyle. The safest area to be drilled in occipital condyle is the 4th quarter as no important structure is located against this region. This study would help in surgeries of lesions ventral to brainstem and craniovertebral junctional anomalies.
On learning Hamiltonian systems from data
Authors: Bertalan Tom , Dietrich Felix , Mezić Igor , Kevrekidis Ioannis G.
Published: December 2019

Concise, accurate descriptions of physical systems through their conserved quantities abound in the natural sciences. In data science, however, current research often focuses on regression problems, without routinely incorporating additional assumptions about the system that generated the data. Here, we propose to explore a particular type of underlying structure in the data: Hamiltonian systems, where an “energy” is conserved. Given a collection of observations of such a Hamiltonian system over time, we extract phase space coordinates and a Hamiltonian function of them that acts as the generator of the system dynamics. The approach employs an autoencoder neural network component to estimate the transformation from observations to the phase space of a Hamiltonian system. An additional neural network component is used to approximate the Hamiltonian function on this constructed space, and the two components are trained jointly. As an alternative approach, we also demonstrate the use of Gaussian processes for the estimation of such a Hamiltonian. After two illustrative examples, we extract an underlying phase space as well as the generating Hamiltonian from a collection of movies of a pendulum. The approach is fully data-driven and does not assume a particular form of the Hamiltonian function.
Single-layer LaBr2: Two-dimensional valleytronic semiconductor with spontaneous spin and valley polarizations
Authors: Zhao Pei , Ma Yandong , Lei Chengan , Wang Hao , Huang Baibiao , Dai Ying
Published: December 2019

The current focus of valleytronics research lies in how to produce valley polarization. Although many schemes have been broadly studied, spontaneous valley polarization is rarely explored. Here, we report the discovery of a two-dimensional material with the long-pursued spontaneous spin and valley polarizations. Using first-principles calculations, we reveal that single-layer LaBr2 is dynamically and thermally stable, which could be exfoliated from its bulk material. Single-layer LaBr2 is found to be a compelling two-dimensional ferromagnetic semiconductor. More interestingly, we show that single-layer LaBr2 harbors the extremely rare intrinsic valley polarization, owing to the coexistence of inversion symmetry and time-reversal symmetry breakings. Its spontaneous valley polarization reaches 33 meV, sizable enough for operating room-temperature valleytronic physics. Our work thus provides a promising material for experimental studies and practical applications of two-dimensional spintronics and valleytronics.
Magnetic field effects in rigidly linked D-A dyads: Extreme on-resonance quantum coherence effect on charge recombination
Authors: Mims David , Schmiedel Alexander , Holzapfel Marco , Lukzen Nikita N. , Lambert Christoph , Steiner Ulrich E.
Published: December 2019

Charge recombination in the photoinduced charge separated (CS) state of a rigidly linked donor/bridge/acceptor triad with a triarylamine (TAA) donor, a 1,3-diethynyl-2,5-dimethoxy benzene bridge (OMe), and a perylenediimide (PDI) unit as an acceptor, represents a spin chemical paradigm case of a rigid radical ion pair formed with singlet spin and recombining almost exclusively to the locally excited PDI triplet state (3PDI). The magnetic field dependence of the CS state decay and 3PDI formation kinetics are investigated from 0 to 1800 mT by nanosecond laser flash spectroscopy. The time-resolved magnetic field affected reaction yields spectra of the CS state population and 3PDI population exhibit a sharp and deep resonance at 18.9 mT, indicating level crossing of the S and T+ levels separated by an exchange interaction of J = 18.9/2 mT at zero field. The kinetics are biexponential around the resonance field and monoexponential outside that range. The monoexponential behavior can be simulated by a classical kinetic model assuming a single field dependent double Lorentzian function for the energy gap dependence of all spin conversion processes. The full field dependence of the kinetics has been simulated quantum theoretically. It has been shown that incoherent and coherent hyperfine coupling contribute to S/T+ spin conversion at all fields and that the biexponentiality of the kinetics at resonance is due to a partitioning of the overall kinetics into 2/3 of the singlet hyperfine states exhibiting strong isotropic coupling to T+ and 1/3 of the singlet hyperfine states that do not or only weakly couple isotropically to T+.
Resolving the puzzle of sound propagation in liquid helium at low temperatures
Authors: Scott Tony C. , Zloshchastiev Konstantin G.
Published: December 2019

Experimental data suggests that, at temperatures below 1 K, the pressure in liquid helium has a cubic dependence on density. Thus the speed of sound scales as a cubic root of pressure. Near a critical pressure point, this speed approaches zero whereby the critical pressure is negative, thus indicating a cavitation instability regime. We demonstrate that to explain this dependence, one has to view liquid helium as a mixture of three quantum Bose liquids: dilute (Gross–Pitaevskii-type) Bose–Einstein condensate, Ginzburg–Sobyanin-type fluid, and logarithmic superfluid. Therefore, the dynamics of such a mixture is described by a quantum wave equation, which contains not only the polynomial (Gross–Pitaevskii and Ginzburg–Sobyanin) nonlinearities with respect to a condensate wavefunction, but also a non-polynomial logarithmic nonlinearity. We derive an equation of state and speed of sound in our model, and show their agreement with the experiment.
Vortices in a curved artery linked to heart disease
Authors: Mandel Savannah
Published: December 2019

A computer simulation shows how vortices moving through a curved artery may correlate with heart disease.
Australasian impact crater buried under the Bolaven volcanic field, Southern Laos
Authors: Sieh Kerry , Herrin Jason , Jicha Brian , Schonwalder Angel Dayana , Moore James D. P. , Banerjee Paramesh , Wiwegwin Weerachat , Sihavong Vanpheng , Singer Brad , Chualaowanich Tawachai , Charusiri Punya
Published: December 2019

The crater and proximal effects of the largest known young meteorite impact on Earth have eluded discovery for nearly a century. We present 4 lines of evidence that the 0.79-Ma impact crater of the Australasian tektites lies buried beneath lavas of a long-lived, 910-km3volcanic field in Southern Laos: 1) Tektite geochemistry implies the presence of young, weathered basalts at the site at the time of the impact. 2) Geologic mapping and40Ar-39Ar dates confirm that both pre- and postimpact basaltic lavas exist at the proposed impact site and that postimpact basalts wholly cover it. 3) A gravity anomaly there may also reflect the presence of a buried ∼17 × 13-km crater. 4) The nature of an outcrop of thick, crudely layered, bouldery sandstone and mudstone breccia 10–20 km from the center of the impact and fractured quartz grains within its boulder clasts support its being part of the proximal ejecta blanket.
A general-purpose protein design framework based on mining sequence–structure relationships in known protein structures
Authors: Zhou Jianfu , Panaitiu Alexandra E. , Grigoryan Gevorg
Published: December 2019

Significance

Evolution has given us proteins that perform amazingly complex tasks in living systems, each molecule appearing “custom-built” for its particular purpose. Protein design seeks to enable the “custom building” of proteins at will, for specific tasks, without waiting for evolution. This is a grand challenge, because how a protein’s 3-dimensional structure and function are encoded in its amino acid sequence is exceedingly difficult to model. In this paper, we argue that sequence–structure encodings can instead be learned directly from proteins of known structure, which enables an approach to design. We are at an exciting time in protein science, where emergent principles inferred from data may allow us to make headway in cases where application of first principles is challenging.
Sensitivity of self-reported noncognitive skills to survey administration conditions
Authors: Chen Yuanyuan , Feng Shuaizhang , Heckman James J. , Kautz Tim
Published: December 2019

Significance

Recent evidence has shown that noncognitive skills matter for success in life and can be shaped through interventions. Because of this evidence, policy makers and researchers have increasingly become interested in measuring noncognitive skills and typically rely on self-reported measures in which respondents rate their own skills. Such self-reports have been applied in program evaluations, as well as school accountability and improvement systems. We demonstrate that self-reports are sensitive to survey administration conditions, including whether a survey administrator describes the skills being assessed and whether respondents receive incentives tied to performance on other tasks. These findings have implications for the interpretation of self-reported measures. Social policies or interventions might affect responses on self-reported noncognitive skills without affecting the skills themselves.
Structure and regulation of human epithelial cell transforming 2 protein
Authors: Chen Mengran , Pan Han , Sun Lingfei , Shi Peng , Zhang Yikan , Li Le , Huang Yuxing , Chen Jianhui , Jiang Peng , Fang Xianyang , Wu Congying , Chen Zhucheng
Published: December 2019

Epithelial cell transforming 2 (Ect2) protein activates Rho GTPases and controls cytokinesis and many other cellular processes. Dysregulation of Ect2 is associated with various cancers. Here, we report the crystal structure of human Ect2 and complementary mechanistic analyses. The data show the C-terminal PH domain of Ect2 folds back and blocks the canonical RhoA-binding site at the catalytic center of the DH domain, providing a mechanism of Ect2 autoinhibition. Ect2 is activated by binding of GTP-bound RhoA to the PH domain, which suggests an allosteric mechanism of Ect2 activation and a positive-feedback loop reinforcing RhoA signaling. This bimodal RhoA binding of Ect2 is unusual and was confirmed with Förster resonance energy transfer (FRET) and hydrogen–deuterium exchange mass spectrometry (HDX-MS) analyses. Several recurrent cancer-associated mutations map to the catalytic and regulatory interfaces, and dysregulate Ect2 in vitro and in vivo. Together, our findings provide mechanistic insights into Ect2 regulation in normal cells and under disease conditions.
Reward does not facilitate visual perceptual learning until sleep occurs
Authors: Tamaki Masako , Berard Aaron V. , Barnes-Diana Tyler , Siegel Jesse , Watanabe Takeo , Sasaki Yuka
Published: December 2019

Significance

Independent lines of research have shown that visual perceptual learning (VPL) is improved by reward or sleep. Here, we show that reward provided during training increased offline performance gains of VPL over sleep. Moreover, during posttraining sleep, reward was associated with longer REM sleep, increased activity in reward processing in the prefrontal region during REM sleep, and decreased activity in the untrained region of early visual areas during NREM and REM sleep. Offline performance gains were correlated with modulated oscillatory activity in reward processing during REM sleep and visual processing during NREM sleep. These results suggest that reward provided during training becomes effective on VPL through the interaction between reward and visual processing during sleep after training.
Behavioral evidence for geomagnetic imprinting and transgenerational inheritance in fruit flies
Authors: Oh In-Taek , Kwon Hye-Jin , Kim Soo-Chan , Kim Hyung-Jun , Lohmann Kenneth J. , Chae Kwon-Seok
Published: December 2019

Certain long-distance migratory animals, such as salmon and sea turtles, are thought to imprint on the magnetic field of their natal area and to use this information to help them return as adults. Despite a growing body of indirect support for such imprinting, direct experimental evidence thereof remains elusive. Here, using the fruit fly as a magnetoreceptive model organism, we demonstrate that exposure to a specific geographic magnetic field during a critical period of early development affected responses to a matching magnetic field gradient later in life. Specifically, hungry flies that had imprinted on a specific magnetic field from 1 of 3 widely separated geographic locations responded to the imprinted field, but not other magnetic fields, by moving downward, a geotactic behavior associated with foraging. This same behavior occurred spontaneously in the progeny of the next generation: female progeny moved downward in response to the field on which their parents had imprinted, whereas male progeny did so only in the presence of these females. These results represent experimental evidence that organisms can learn and remember a magnetic field to which they were exposed during a critical period of development. Although the function of the behavior is not known, one possibility is that imprinting on the magnetic field of a natal area assists flies and their offspring in recognizing locations likely to be favorable for foraging and reproduction.
Shape-controlled single-crystal growth of InP at low temperatures down to 220 °C
Authors: Hettick Mark , Li Hao , Lien Der-Hsien , Yeh Matthew , Yang Tzu-Yi , Amani Matin , Gupta Niharika , Chrzan Daryl C. , Chueh Yu-Lun , Javey Ali
Published: December 2019

III–V compound semiconductors are widely used for electronic and optoelectronic applications. However, interfacing III–Vs with other materials has been fundamentally limited by the high growth temperatures and lattice-match requirements of traditional deposition processes. Recently, we developed the templated liquid-phase (TLP) crystal growth method for enabling direct growth of shape-controlled single-crystal III-Vs on amorphous substrates. Although in theory, the lowest temperature for TLP growth is that of the melting point of the group III metal (e.g., 156.6 °C for indium), previous experiments required a minimum growth temperature of 500 °C, thus being incompatible with many application-specific substrates. Here, we demonstrate low-temperature TLP (LT-TLP) growth of single-crystalline InP patterns at substrate temperatures down to 220 °C by first activating the precursor, thus enabling the direct growth of InP even on low thermal budget substrates such as plastics and indium-tin-oxide (ITO)–coated glass. Importantly, the material exhibits high electron mobilities and good optoelectronic properties as demonstrated by the fabrication of high-performance transistors and light-emitting devices. Furthermore, this work may enable integration of III–Vs with silicon complementary metal-oxide-semiconductor (CMOS) processing for monolithic 3D integrated circuits and/or back-end electronics.
Fin ray patterns at the fin-to-limb transition
Authors: Stewart Thomas A. , Lemberg Justin B. , Taft Natalia K. , Yoo Ihna , Daeschler Edward B. , Shubin Neil H.
Published: December 2019

The fin-to-limb transition was marked by the origin of digits and the loss of dermal fin rays. Paleontological research into this transformation has focused on the evolution of the endoskeleton, with little attention paid to fin ray structure and function. To address this knowledge gap, we study the dermal rays of the pectoral fins of 3 key tetrapodomorph taxa—Sauripterus taylori(Rhizodontida),Eusthenopteron foordi(Tristichopteridae), andTiktaalik roseae(Elpistostegalia)—using computed tomography. These data show several trends in the lineage leading to digited forms, including the consolidation of fin rays (e.g., reduced segmentation and branching), reduction of the fin web, and unexpectedly, the evolution of asymmetry between dorsal and ventral hemitrichia. InEusthenopteron, dorsal rays cover the preaxial endoskeleton slightly more than ventral rays. InTiktaalik, dorsal rays fully cover the third and fourth mesomeres, while ventral rays are restricted distal to these elements, suggesting the presence of ventralized musculature at the fin tip analogous to a fleshy “palm.” Asymmetry is also observed in cross-sectional areas of dorsal and ventral rays.Eusthenopterondorsal rays are slightly larger than ventral rays; by contrast,Tiktaalikdorsal rays can be several times larger than ventral rays, and degree of asymmetry appears to be greater at larger sizes. Analysis of extant osteichthyans suggests that cross-sectional asymmetry in the dermal rays of paired fins is plesiomorphic to crown group osteichthyans. The evolution of dermal rays in crownward stem tetrapods reflects adaptation for a fin-supported elevated posture and resistance to substrate-based loading prior to the origin of digits.
The proton electrochemical gradient induces a kinetic asymmetry in the symport cycle of LacY
Authors: Jiang Xiaoxu , Ermolova Natalia , Lim John , Choi Seo Woo , Kaback H. Ronald
Published: December 2019

Significance

Protonation and deprotonation of Glu325 with a pK
a
of 10.5 is required for symport. Moreover, the H
+
electrochemical gradient (

∆

μ

∼

H

+

) accelerates deprotonation on the intracellular side with a 50- to 100-fold decrease in the K
m
. To probe the pK on the cytoplasmic side of the membrane, rates of lactose/H
+
efflux were determined from pH 5.0 to 9.0 without or with a membrane potential (ΔΨ, interior positive) in right-side-out membrane vesicles. WT lactose efflux has an apparent pK of ∼7.2 that is unaffected by ΔΨ, mutant E325A is defective, and pH or ΔΨ (interior positive) has no effect. The effect of ΔΨ (interior positive) on the K
m
for efflux with WT LacY is insignificant relative to the marked effect on influx.