Cut-off Method Research Articles

Bright ab initio photoluminescence of NV+ in diamond

The positively charged nitrogen vacancy (NV+) center in diamond has been traditionally treated as a dark state due to the experimental lack of an optical signature. Recent computational studies have shown that it is possible for the NV+ defect to have an excited state transition equivalent to that of the negatively charged (NV−) center, but no photoluminescence (PL) predictions have been reported so far. We report the first ab initio calculation showing that the NV+ center presents quantum emission, with zero phonon line at 765 nm and a non-zero transition dipole moment, approximately one quarter of the transition dipole moment of NV−. We calculate the energy levels of the multielectron states under the time-dependent density functional theory (singlet and triplet E states), and using our recently developed frequency cutoff method, we predict the full PL spectrum. Our results suggest that this state cannot be considered intrinsically “dark” and charge specific quenching mechanisms should be investigated as the cause of the lack of optical activity in experimental characterizations.

CHARMM-GUI Nanomaterial Modeler for Modeling and Simulation of Nanomaterial Systems.

Molecular modeling and simulation are invaluable tools for nanoscience that predict mechanical, physicochemical, and thermodynamic properties of nanomaterials and provide molecular-level insight into underlying mechanisms. However, building nanomaterial-containing systems remains challenging due to the lack of reliable and integrated cyberinfrastructures. Here we present Nanomaterial Modeler in CHARMM-GUI, a web-based cyberinfrastructure that provides an automated process to generate various nanomaterial models, associated topologies, and configuration files to perform state-of-the-art molecular dynamics simulations using most simulation packages. The nanomaterial models are based on the interface force field, one of the most reliable force fields (FFs). The transferability of nanomaterial models among the simulation programs was assessed by single-point energy calculations, which yielded 0.01% relative absolute energy differences for various surface models and equilibrium nanoparticle shapes. Three widely used Lennard-Jones (LJ) cutoff methods are employed to evaluate the compatibility of nanomaterial models with respect to conventional biomolecular FFs: simple truncation at r = 12 Å (12 cutoff), force-based switching over 10 to 12 Å (10-12 fsw), and LJ particle mesh Ewald with no cutoff (LJPME). The FF parameters with these LJ cutoff methods are extensively validated by reproducing structural, interfacial, and mechanical properties. We find that the computed density and surface energies are in good agreement with reported experimental results, although the simulation results increase in the following order: 10-12 fsw <12 cutoff < LJPME. Nanomaterials in which LJ interactions are a major component show relatively higher deviations (up to 4% in density and 8% in surface energy differences) compared with the experiment. Nanomaterial Modeler's capability is also demonstrated by generating complex systems of nanomaterial-biomolecule and nanomaterial-polymer interfaces with a combination of existing CHARMM-GUI modules. We hope that Nanomaterial Modeler can be used to carry out innovative nanomaterial modeling and simulations to acquire insight into the structure, dynamics, and underlying mechanisms of complex nanomaterial-containing systems.

Prevalence of inadequate intake of folate in the post-fortification era: data from the Brazilian National Dietary Surveys 2008-2009 and 2017-2018.

The objectives were to compare the evolution of dietary folate intake, to estimate the prevalence of folate inadequacy (POFI) and the contribution of food groups to folate intake (dietary folate plus folic acid from fortified foods) in two post-fortification periods in the Brazilian population, according to life stages, geographic regions and per capita income. Population-based study including representative data from the National Dietary Survey - Brazilian Household Budget Surveys (NDS-HBS) 2008-2009 and 2017-2018, with a total of 32749 (2008-2009) and 44744 (2017-2018) individuals aged ≥ 10 years old, excluding pregnant and lactating women. The National Cancer Institute method was used to estimate the distributions of usual dietary folate intake. POFI was estimated according to estimated average requirement cut-off point method. After 10 years of the first NDS-HBS, POFI has increased in all sex-age groups, except for 10-13 years. POFI among women of reproductive age was around 30 and 40 % in 2008-2009 and 2017-2018. Higher POFI was observed in the North region. The top five food groups contributors to folate intake in Brazil were beans, breads, pasta and pizza, cakes and cookies and non-alcoholic beverages groups in both periods, differing in the rank order of the last two groups. Although being a country that has adopted mandatory folic acid flour fortification for almost two decades, increased POFI was observed in 2017-2018. This study brings significant scientific information, which can help understand folate dietary data in different contexts and consequently guide the approach for public health fortification strategies.

A Method for Solving Percolation Overflow Boundary Based on Maximum of Horizontal Energy Loss Rate

The determination of overflow boundary is a prerequisite for the accurate solution of the seepage field by the finite element method. In this paper, a method for solving overflow boundary according to the maximum value of horizontal energy loss rate is proposed, which based on the analysis of the physical meaning of functional and the water head distribution of seepage field under different overflow boundaries. This method considers that the overflow boundary that makes the horizontal energy loss rate reach the maximum value is the real boundary overflow. Compared with the previous iterative computation method of overflow point and free surface, the method of solving overflow boundary based on the maximum horizontal energy loss rate does not need iteration, so the problem of non-convergence does not exist. The relative error of the overflow points is only 1.54% and 0.98% by calculating the two-dimensional model of the glycerol test and the three-dimensional model of the electric stimulation test, respectively. Compared with the overflow boundary calculated by the node virtual flow method, improved cut-off negative pressure method, initial flow method, and improved discarding element method, this method has a higher accuracy.

Going Beyond Sweep Voltammetry: Alternative Approaches in Search of the Elusive Electrochemical Stability of Polymer Electrolytes

Solid polymer electrolytes (SPEs) are promising candidates for solid-state lithium-ion batteries. Potentially, they can be used with lithium metal anodes and high-voltage cathodes, provided that their electrochemical stability is sufficient. Thus far, the oxidative stability has largely been asserted based on results obtained with sweep voltammetry, which are often determined and reliant on arbitrary assessments that are highly dependent on the experimental conditions and do not take the interaction between the electrolyte and the electrode material into account. In this study, alternative techniques are introduced to address the pitfalls of sweep voltammetry for determining the oxidative stability of SPEs. Staircase voltammetry involves static conditions and eliminates the kinetic aspects of sweep voltammetry, and coupled with impedance spectroscopy provides information of changes in resistance and interphase layer formation. Synthetic charge–discharge profile voltammetry applies the real voltage profile of the active material of interest. The added effect of the electrode active material is investigated with a cut-off increase cell cycling method where the upper cut-off voltage during galvanostatic cycling is gradually increased. The feasibility of these techniques has been tested with both poly(ethylene oxide) and poly(trimethylene carbonate) combined with LiTFSI, thereby showing the applicability for several categories of SPEs.

A novel cut-off grade method for increasing the sustainability of underground metalliferous mining operations

The determination of a cut-off grade is considered to be one of the main steps in the design and strategic planning of mining operations. This is due to its role in distinguishing between waste material and valuable ore. This becomes increasingly important as the mining industry is facing lower grades within an uncertain market. The implementation of pre-concentration systems prior to main processing has significant potential to increase the sustainability and resource utilisation of mining operations, which can result in the reduction of mine cut-off grade. This paper reviews the technical concepts of integration of pre-concentration systems into underground mines and presents a novel method for underground cut-off grade calculation. The proposed model is implemented on a sublevel stoping operation to illustrate the impacts and advantages of the underground pre-concentration integration. The outputs of this study and investigation of various scenarios prove an increase in the profitability, efficiency and sustainability of the underground operations.

Energy-Based Interface Detection for Phase Change Processes of Monatomic Fluids in Nanoconfinements.

An energy-based liquid-vapor interface detection method is presented using molecular dynamics simulations of liquid menisci confined between two parallel plates under equilibrium and evaporation/condensation conditions. This method defines the liquid-vapor interface at the location where the average kinetic energy of atoms first exceeds the average potential energy imposed by all neighboring molecules. This definition naturally adapts to the location of the menisci relative to the walls and can properly model the behavior of the liquid adsorbed layers. Unlike the density cutoff methods frequently used in the literature that suffer from density layering effects, this new method gives smooth and continuous liquid-vapor interfaces in nanoconfinements. Surface tension values calculated from the equilibrium MD simulations match the Young-Laplace equation better when using the radius of curvatures calculated from this method. Overall, this energy-based liquid-vapor interface detection method can be used in studies of nanoscale phase change processes and other relevant applications.

Pretreatment prognostic nutritional index as a prognostic marker in head and neck cancer: a systematic review and meta-analysis

The predictive value of the pretreatment prognostic nutritional index (PNI) for head and neck cancer (HNC) remains controversial. We conducted a meta-analysis to assess the predictive value of PNI in HNC patients. A systematic search through internet databases including PubMed, Embase, and Cochrane Library for qualified studies estimating the association of PNI with HNC patient survival was performed. Overall survival (OS), progression-free survival (PFS), disease-specific survival (DSS), disease-free survival (DFS) and distant metastasis-free survival (DMFS) data were collected and evaluated. A random-effects model was used to calculate the pooled hazard ratios (pHRs) and corresponding 95% confidence intervals (CIs). A total of 7815 HNC patients from 14 eligible studies were involved. Pooled analysis showed that low pretreatment PNI was correlated with poor OS (pHR: 1.93, 95% CI 1.62–2.30, p < 0.001), PFS (pHR: 1.51, 95% CI 1.19–1.92, p = 0.008), DSS (pHR: 1.98, 95% CI 1.12–3.50, p < 0.001), DFS (pHR: 2.20, 95% CI 1.66–2.91, p < 0.001) and DMFS (pHR: 2.04, 95% CI 1.74–2.38, p < 0.001). Furthermore, low pretreatment PNI was correlated with poor OS despite variations in the cancer site, sample size, PNI cut-off value, analysis method (multivariate analysis or univariate analysis) and treatment modality in subgroup analysis. Elevated pretreatment PNI is correlated with a superior prognosis in HNC patients and could be used as a biomarker in clinical practice for prognosis prediction and treatment stratification.

Developing Cutoff Scores for the Inventory of Callous-Unemotional Traits (ICU) in Justice-Involved and Community Samples

ABSTRACT Objective: The recent addition of the callous-unemotional (CU) traits specifier, “with Limited Prosocial Emotions (LPE),” to major classification systems has prompted the need for assessment tools that aid in the identification of elevations on these traits for diagnostic purposes. The goal of the current study was to use and evaluate multiple methods for establishing cutoff scores for the multi-informant questionnaire, the Inventory of Callous-Unemotional Traits (ICU). Method: The present study compared the clinical utility of various proposed cutoff methods and scores (i.e., empirically derived cutoffs using receiver operating characteristic (ROC), normative cutoffs, and rational scoring approximations of LPE criteria) in both a longitudinal sample of justice-involved male adolescents (N = 1,216; M age = 15.29, SD = 1.29) and a cross-sectional sample of school children (N = 289; M age = 11.47 years; SD = 2.26). Results: Methods resulted in a range of cutoff scores with substantial diagnostic overlap and validity. Specifically, they designated justice-involved adolescents at risk for later delinquency, aggression, and rearrests, and they designated school children more likely to be rated by parents and teacher as having conduct problems and rated by peers as being rejected and mean. Conclusions: The results lead to ranges of ICU scores that have support for their validity and can help to guide clinical decisions about children and adolescents who may be elevated on CU traits.

Feasibility and Acceptability of Photographic Food Record, Food Diary and Weighed Food Record in People with Serious Mental Illness.

People with serious mental illness (SMI) experience challenges that may make typical dietary assessment methods less feasible and accurate. This study aims to determine the feasibility, acceptability and preliminary validity of a 3-day photographic food record (PR), a 1-day food diary (FD) and a 1-day weighed food protocol (WR) in people with SMI. Participants completed measures at two timepoints, with a 4-week interval. Feasibility and acceptability for each method were measured through four outcomes: percent of completers, quality assessment, number of participants requiring technical devices and satisfaction questionnaire. Relative validity was measured by agreement in estimated energy intake between methods, using Bland–Altman analysis and WR as the benchmark, and prevalence of misreporting, using the Goldberg cut-off method, updated by Black. In total, 63 participants were recruited, with a dropout rate of 19.0% prior to timepoint 1 and additional 6.4% prior to timepoint 2. Quality deficits were identified for all methods. The FD was most acceptable to participants, followed by the PR. The difference in estimated energy intake between assessment methods was not statistically significant, though there was considerable individual variability. Underreporting was considerable across all methods but appeared highest in the PR. A FD and PR present as feasible and acceptable methods for assessing dietary intake in people with SMI. Further validity testing is required. In addition, clear guidance for completion and removal of potential barriers is required for participants.

Differences among [18F]FDG PET-derived parameters in lung cancer produced by three software packages

Investigation of differences in derived [18F]FDG PET metabolic and volumetric parameters among three different software programs in lung cancer. A retrospective analysis was performed on a group of 98 lung cancer patients who underwent a baseline [18F]FDG PET/CT study. To assess appropriate delineation methods, the NEMA phantom study was first performed using the following software: Philips EBW (Extended Brilliance Workstation), MIM Software and Rover. Based on this study, the best cut-off methods (dependent on tumour size) were selected, extracted and applied for lung cancer delineation. Several semiquantitative [18F]FDG parameters (SUVmax, SUVmean, TLG and MTV) were assessed and compared among the three software programs. The parameters were assessed based on body weight (BW), lean body mass (LBM) and Bq/mL. Statistically significant differences were found in SUVmean (LBM) between MIM Software and Rover (4.62 ± 2.15 vs 4.84 ± 1.20; p < 0.005), in SUVmean (Bq/mL) between Rover and Philips EBW (21,852.30 ± 21,821.23 vs 19,274.81 ± 13,340.28; p < 0.005) and Rover and MIM Software (21,852.30 ± 21,821.23 vs 19,399.40 ± 10,051.30; p < 0.005), and in MTV between MIM Software and Philips EBW (19.87 ± 25.83 vs 78.82 ± 228.00; p = 0.0489). This study showed statistically significant differences in the estimation of semiquantitative parameters using three independent image analysis tools. These findings are important for performing further diagnostic and treatment procedures in lung cancer patients.

Prognostic impact of the pre-treatment controlling nutritional status score in patients with non-small cell lung cancer: A meta-analysis.

Background:The influence of pre-treatment controlling nutritional status (CONUT) score on the prognosis of non-small cell lung cancer (NSCLC) patients is inconclusive. We performed this meta-analysis to evaluate the prognostic significance of CONUT score in NSCLC patients.Methods:A systematic literature review was conducted using PubMed, Embase, and the Cochrane Library databases. The hazard ratio (HR) and 95% confidence interval (CI) were extracted to assess the correlation between the CONUT score and the overall survival (OS), disease-free survival (DFS), recurrence-free survival (RFS), as well as the cancer-specific survival.Results:A total of 11 studies with 3029 patients were included in the analysis. Pooled results indicated that a high CONUT score was positively correlated with poor OS (HR: 1.63, 95%CI: 1.40–1.88, P < .001) and shortened DFS/RFS (HR: 1.65, 95%CI: 1.35–2.01, P < .001), but no significant relationship with the cancer-specific survival (HR: 1.28, 95%CI: 0.60–2.73, P = .517) was identified. The negative effect of high CONUT score on the OS and DFS/RFS was detected in every subgroup with varying treatment methods, cancer stage, CONUT cut-off values, sample size, and analysis methods of HR. Additionally, preoperative high CONUT score was an independent predictor of postoperative complications (odds ratio: 1.58, 95%CI: 1.21–2.06, P = .001) in NSCLC. Last but not least, high CONUT score was not significantly correlated with the patients’ sex, smoking status, cancer stage, lymphatic invasion, vascular invasion, pleural invasion, and pathological cancer type.Conclusion:These results demonstrate that high CONUT score is positively related to poor prognoses. The CONUT score may therefore be considered as an effective prognostic marker in NSCLC patients.

Investigating Preservice Science Teachers’ Cognitive Structures on Environmental Issues

Environmental knowledge and awareness of individuals affect their attitudes and behavior toward the environment. In this regard, it is essential to specify how environmental issues are interpreted in individuals’ cognitive structures. This study aims to investigate preservice science teachers’ cognitive structures on environmental issues. The study was conducted with 78 third-year preservice science teachers. The data were collected through a word association test that contains eight stimulus words about environmental problems and protecting the environment. Global warming, greenhouse effect, radiation, and acid rain were chosen for environmental problems; recycling, waste disposal, sustainability, and solar energy were selected for protecting the environment. Besides, preservice science teachers were asked to write a sentence for each stimulus word. Two concept networks were created based on the cut-off point method for the word association test, and content analysis was used for sentences. Besides, by comparing the data obtained from the concept networks and sentence analysis, an attempt was made to obtain more in-depth information. It is concluded that preservice science teachers focused on daily life rather than scientific facts about environmental issues. In this respect, new courses such as Green Chemistry may effectively eliminate alternative conceptions and raise awareness on environmental issues.

Bayesian Binary Mixture Models as a Flexible Alternative to Cut-Off Analysis of ELISA Results, a Case Study of Seoul Orthohantavirus.

Serological assays, such as the enzyme-linked immunosorbent assay (ELISA), are popular tools for establishing the seroprevalence of various infectious diseases in humans and animals. In the ELISA, the optical density is measured and gives an indication of the antibody level. However, there is variability in optical density values for individuals that have been exposed to the pathogen of interest, as well as individuals that have not been exposed. In general, the distribution of values that can be expected for these two categories partly overlap. Often, a cut-off value is determined to decide which individuals should be considered seropositive or seronegative. However, the classical cut-off approach based on a putative threshold ignores heterogeneity in immune response in the population and is thus not the optimal solution for the analysis of serological data. A binary mixture model does include this heterogeneity, offers measures of uncertainty and the direct estimation of seroprevalence without the need for correction based on sensitivity and specificity. Furthermore, the probability of being seropositive can be estimated for individual samples, and both continuous and categorical covariates (risk-factors) can be included in the analysis. Using ELISA results from rats tested for the Seoul orthohantavirus, we compared the classical cut-off method with a binary mixture model set in a Bayesian framework. We show that it performs similarly or better than cut-off methods, by comparing with real-time quantitative polymerase chain reaction (RT-qPCR) results. We therefore recommend binary mixture models as an analysis tool over classical cut-off methods. An example code is included to facilitate the practical use of binary mixture models in everyday practice.

LncRNA AWPPH as a prognostic predictor in human cancers in Chinese population: evidence from meta-analysis.

Background: Long non-coding RNA associated with poor prognosis of hepatocellular carcinoma (AWPPH) is dysregulated in a variety of human cancers. However, the prognostic value of AWPPH in various cancers remains unclear.Methods: Comprehensive literature search was performed in PubMed, Web of Science, CNKI and Wangfang databases, and eligible studies were obtained according to the inclusion and exclusion criteria. The pooled hazard ratios (HRs) and odds ratios (ORs) were applied to assess the clinical value of AWPPH expression for overall survival (OS) and clinicopathological features.Results: A total of 19 articles including 1699 cancer patients were included in the study. The pooled results demonstrated that evaluated AWPPH expression was positively related to a poorer overall survival of patients with cancers (HR = 1.79, 95%CI: 1.44–2.14, P<0.001). Subgroup analysis revealed that tumor type and sample size affect the predictive value of AWPPH on OS, whereas cut-off value and HR estimation method have no impact on it. In addition, the pooled data also showed that AWPPH was positively linked to advanced TNM stage (OR = 2.50, 95%CI: 1.94–3.22, P<0.001), bigger tumor size (OR = 2.64, 95%CI: 1.47–4.73, P=0.001), macro-vascular invasion (OR = 2.08, 95%CI: 1.04–4.16, P=0.04) and lymph node metastasis (OR = 2.68, 95%CI: 1.82–3.96, P<0.001). Moreover, the results of the trim and fill analysis confirmed the reliability of our finding.Conclusions: Up-regulation of AWPPH was associated with advanced TNM stage, bigger tumor size, worse lymph node metastasis, macro-vascular invasion and shorter overall survival, suggesting that AWPPH may serve as a biomarker for prognosis and clinicopathological characteristics in human cancers among the Chinese population.

Perpetual cutoff method and CDE′(K, N) condition on graphs

Perpetual cutoff method and CDE′(K, N) condition on graphs

Joukowski’s wake model for tip-splitting rotors

The interaction between a tip vortex and a solid surface is responsible for premature structural component fatigue in wind turbines and undesirable noise in helicopter rotors during low speed and descending flight. One noise reduction strategy uses a modified airfoil to split and spread the vorticity in two tip vortices. The present paper aims to provide the wake structure produced by such a rotor for wind turbine and helicopter regimes. We use a filamentary approach, such that vortices are assumed to roll-up quickly to form thin vortex filaments of finite but small size and compute the induced velocity using a cut-off method. The structure of the wake is analyzed in the near- and far-fields separately. It is found to have a dual nature and to be well-described by a twisted vortex pair locally aligned along with a larger helical structure. The linear stability of the far-wake with respect to long-wave displacements is also analyzed. Two kinds of instability modes are obtained associated with a pairing between successive turns of the large helical structure and a pairing between successive turns of the vortex pair.

Particle–particle particle–tree code for planetary system formation with individual cut-off method: GPLUM

Abstract In a standard theory of the formation of the planets in our Solar System, terrestrial planets and cores of gas giants are formed through accretion of kilometer-sized objects (planetesimals) in a protoplanetary disk. Gravitational N-body simulations of a disk system made up of numerous planetesimals are the most direct way to study the accretion process. However, the use of N-body simulations has been limited to idealized models (e.g., perfect accretion) and/or narrow spatial ranges in the radial direction, due to the limited number of simulation runs and particles available. We have developed new N-body simulation code equipped with a particle–particle particle–tree (P3T) scheme for studying the planetary system formation process: GPLUM. For each particle, GPLUM uses the fourth-order Hermite scheme to calculate gravitational interactions with particles within cut-off radii and the Barnes–Hut tree scheme for particles outside the cut-off radii. In existing implementations, P3T schemes use the same cut-off radius for all particles, making a simulation become slower when the mass range of the planetesimal population becomes wider. We have solved this problem by allowing each particle to have an appropriate cut-off radius depending on its mass, its distance from the central star, and the local velocity dispersion of planetesimals. In addition to achieving a significant speed-up, we have also improved the scalability of the code to reach a good strong-scaling performance up to 1024 cores in the case of N = 106.

A cut-off method to realize the exact boundary controllability of nodal profile for Saint-Venant systems on general networks with loops

In this paper, we consider the exact boundary controllability of nodal profile for Saint-Venant systems on a network with loops. In the case with one object-node, the proposed cut-off method not only contains the results obtained in [13] on a special network with a triangle-like loop in a unified way, but also generalizes these results to general networks with loops. Based on the results in the case with one object-node, the proposed cut-off method can also be applied successfully to the case with several object-nodes.

Joint hypermobility and its association with self-reported knee health: A cross-sectional study of healthy Australian adults.

The primary aim of this study was to determine the association between generalized joint hypermobility (GJH), knee-specific hypermobility (KSH) and self-reported knee health in an Australian population. Secondary aims included elucidating ethnic/gender differences in GJH/KSH prevalence and knee health, and identifying KSH using a novel knee extension range of motion cut-off method. Knee extension range, Beighton score, and 5 domains of the Knee Injury and Osteoarthritis Outcome Score (KOOS) were collected from adults aged 18-101years self-identifying as healthy, and were grouped by ethnicity and gender. Two established Beighton score criteria and 1 novel knee extension range cut-off method were used to determine GJH and KSH respectively. Point-biserial correlation tested the associations between GJH/KSH and KOOS. Differences in GJH/KSH prevalence and knee health between ethnic/gender groups were determined with the Chi-squared test. Of 732 participants (50% male), 80.3% were Caucasian. No correlations were found between GJH and KOOS while a very weak correlation was found between KSH and 1 KOOS domain (r>-.30; P=.04). Prevalence of GJH was higher in non-Caucasians (17.4% vs 5.6%, P<.001) and females (4.4% vs 1.1%, P=.007). Prevalence of KSH between ethnic and gender groups was not significantly different (P=.50 and P=.69 respectively). Non-Caucasians scored higher (better) in all KOOS domains than Caucasians (all P<.05). Those who met the age- and gender-specific criteria for GJH/KSH did not report worse knee health than their non-hypermobile counterparts. Clinicians can assure individuals who exhibit GJH/KSH that these are not associated with lower knee health and function.