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Transient Dynamics Simulation of Airflow in a CT-Scanned Human Airway Tree: More or Fewer Terminal Bronchi?
Authors: Qi S, Zhang B, Teng Y, Li J, Yue Y, Kang Y, Qian W Abstract Using computational fluid dynamics (CFD) method, the feasibility of simulating transient airflow in a CT-based airway tree with more than 100 outlets for a whole respiratory period is studied, and the influence of truncations of terminal bronchi on CFD characteristics is investigated. After an airway model with 122 outlets is extracted from CT images, the transient airflow is simulated. Spatial and temporal variations of flow velocity, wall pressure, and wall shear stress are presented; the flow pattern and lobar distribution of air are gotten as ...
Source: Computational and Mathematical Methods in Medicine - January 17, 2018 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Corrigendum to "Development of a Patient-Specific Finite Element Model for Predicting Implant Failure in Pelvic Ring Fracture Fixation".
Corrigendum to "Development of a Patient-Specific Finite Element Model for Predicting Implant Failure in Pelvic Ring Fracture Fixation". Comput Math Methods Med. 2017;2017:8956549 Authors: Shim V, Gather A, Höch A, Schreiber D, Grunert R, Peldschus S, Josten C, Böhme J Abstract [This corrects the article DOI: 10.1155/2017/9403821.]. PMID: 29333195 [PubMed - in process] (Source: Computational and Mathematical Methods in Medicine)
Source: Computational and Mathematical Methods in Medicine - January 17, 2018 Category: Statistics Tags: Comput Math Methods Med Source Type: research

The Dynamical Behaviors for a Class of Immunogenic Tumor Model with Delay.
Authors: Bi P, Liu Z, Muthoni MD, Pang J Abstract This paper aims at studying the model proposed by Kuznetsov and Taylor in 1994. Inspired by Mayer et al., time delay is introduced in the general model. The dynamic behaviors of this model are studied, which include the existence and stability of the equilibria and Hopf bifurcation of the model with discrete delays. The properties of the bifurcated periodic solutions are studied by using the normal form on the center manifold. Numerical examples and simulations are given to illustrate the bifurcation analysis and the obtained results. PMID: 29312457 [PubMed - in...
Source: Computational and Mathematical Methods in Medicine - January 11, 2018 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Modeling Impact of Temperature and Human Movement on the Persistence of Dengue Disease.
Authors: Phaijoo GR, Gurung DB Abstract Dengue is a vector-borne infectious disease endemic in many parts of the world. The disease is spreading in new places due to human movement into the dengue disease supporting areas. Temperature is the major climatic factor which affects the biological processes of the mosquitoes and their interaction with the viruses. In the present work, we propose a multipatch model to assess the impact of temperature and human movement in the transmission dynamics of dengue disease. The work consists of system of ordinary differential equations that describe the transmission dynamics of d...
Source: Computational and Mathematical Methods in Medicine - January 11, 2018 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Association of Stressful Life Events with Psychological Problems: A Large-Scale Community-Based Study Using Grouped Outcomes Latent Factor Regression with Latent Predictors.
Authors: Hassanzadeh A, Heidari Z, Feizi A, Hassanzadeh Keshteli A, Roohafza H, Afshar H, Adibi P Abstract Objective: The current study is aimed at investigating the association between stressful life events and psychological problems in a large sample of Iranian adults. Method: In a cross-sectional large-scale community-based study, 4763 Iranian adults, living in Isfahan, Iran, were investigated. Grouped outcomes latent factor regression on latent predictors was used for modeling the association of psychological problems (depression, anxiety, and psychological distress), measured by Hospital Anxiety and Depres...
Source: Computational and Mathematical Methods in Medicine - January 11, 2018 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Dynamics of Immune Checkpoints, Immune System, and BCG in the Treatment of Superficial Bladder Cancer.
Authors: Saad FT, Hincal E, Kaymakamzade B Abstract This paper aims to study the dynamics of immune suppressors/checkpoints, immune system, and BCG in the treatment of superficial bladder cancer. Programmed cell death protein-1 (PD-1), cytotoxic T-lymphocyte-associated antigen 4 (CTLA4), and transforming growth factor-beta (TGF-β) are some of the examples of immune suppressors/checkpoints. They are responsible for deactivating the immune system and enhancing immunological tolerance. Moreover, they categorically downregulate and suppress the immune system by preventing and blocking the activation of T-cells, wh...
Source: Computational and Mathematical Methods in Medicine - January 11, 2018 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Preventing Neurodegenerative Memory Loss in Hopfield Neuronal Networks Using Cerebral Organoids or External Microelectronics.
In this study, we connect an auxiliary network of neurons, which models the BMI device, to the original Hopfield network and train it to converge to its own auxiliary memory patterns. Injuries to the original Hopfield memory network, induced through neurodegeneration, for instance, can then be analyzed with the goal of evaluating the ability of the BMI to aid in memory retrieval tasks. Dense connectivity between the auxiliary and Hopfield networks is shown to promote robustness of memory retrieval tasks for both optimal and nonoptimal memory sets. Our computations estimate damage levels and parameter ranges for which full ...
Source: Computational and Mathematical Methods in Medicine - January 11, 2018 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Estimating and Interpreting Effects from Nonlinear Exposure-Response Curves in Occupational Cohorts Using Truncated Power Basis Expansions and Penalized Splines.
Authors: Malloy EJ, Kapellusch JM, Garg A Abstract Truncated power basis expansions and penalized spline methods are demonstrated for estimating nonlinear exposure-response relationships in the Cox proportional hazards model. R code is provided for fitting models to get point and interval estimates. The method is illustrated using a simulated data set under a known exposure-response relationship and in a data application examining risk of carpal tunnel syndrome in an occupational cohort. PMID: 29312462 [PubMed - in process] (Source: Computational and Mathematical Methods in Medicine)
Source: Computational and Mathematical Methods in Medicine - January 11, 2018 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Assessment of Differential Item Functioning in Health-Related Outcomes: A Simulation and Empirical Analysis with Hierarchical Polytomous Data.
Conclusions: The current study showed negligible difference between OLR and HOLR in detecting DIF with polytomously scored items in a hierarchical structure. Implications and considerations while analyzing real data were also discussed. PMID: 29312463 [PubMed - in process] (Source: Computational and Mathematical Methods in Medicine)
Source: Computational and Mathematical Methods in Medicine - January 11, 2018 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Correcting Classifiers for Sample Selection Bias in Two-Phase Case-Control Studies.
In conclusion, we provide guidance for choosing correction methods when training classifiers on biased samples. For random forests, our method outperforms state-of-the-art procedures if distribution assumptions are roughly fulfilled. We provide our implementation in the R package sambia. PMID: 29312464 [PubMed - in process] (Source: Computational and Mathematical Methods in Medicine)
Source: Computational and Mathematical Methods in Medicine - January 11, 2018 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Modeling and Control for HIV/AIDS Transmission in China Based on Data from 2004 to 2016.
Authors: Li Z, Teng Z, Miao H Abstract HIV is one of the major life-threatening viruses that are spreading in the People's Republic of China (China for short). A susceptible-exposed in the latent stage-infectious (SEI) model is established to sketch the evolution of epidemic. The basic reproduction number is defined. By constructing Lyapunov function, globally asymptotical stabilities of the disease-free and endemic equilibria are given. Then, optimal control theory is applied in HIV/AIDS epidemic. Precaution, screening, and treatment of control variables are introduced and a new model with control is established. ...
Source: Computational and Mathematical Methods in Medicine - January 11, 2018 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Computing Individual Risks Based on Family History in Genetic Disease in the Presence of Competing Risks.
Authors: Nuel G, Lefebvre A, Bouaziz O Abstract When considering a genetic disease with variable age at onset (e.g., familial amyloid neuropathy, cancers), computing the individual risk of the disease based on family history (FH) is of critical interest for both clinicians and patients. Such a risk is very challenging to compute because (1) the genotype X of the individual of interest is in general unknown, (2) the posterior distribution ℙ(X∣FH, T> t) changes with t (T is the age at disease onset for the targeted individual), and (3) the competing risk of death is not negligible. In this work, we present mod...
Source: Computational and Mathematical Methods in Medicine - January 11, 2018 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Uncertainty Analysis in the Calibration of an Emission Tomography System for Quantitative Imaging.
Authors: D'Arienzo M, Cox M Abstract It is generally acknowledged that calibration of the imaging system (be it a SPECT or a PET scanner) is one of the critical components associated with in vivo activity quantification in nuclear medicine. The system calibration is generally performed through the acquisition of a source with a known amount of radioactivity. The decay-corrected calibration factor is the "output" quantity in a measurement model for the process. This quantity is a function of a number of "input" variables, including total counts in the volume of interest (VOI), radionuclide activi...
Source: Computational and Mathematical Methods in Medicine - January 11, 2018 Category: Statistics Tags: Comput Math Methods Med Source Type: research

A Variational Level Set Approach Based on Local Entropy for Image Segmentation and Bias Field Correction.
Authors: Tang J, Jiang X Abstract Image segmentation has always been a considerable challenge in image analysis and understanding due to the intensity inhomogeneity, which is also commonly known as bias field. In this paper, we present a novel region-based approach based on local entropy for segmenting images and estimating the bias field simultaneously. Firstly, a local Gaussian distribution fitting (LGDF) energy function is defined as a weighted energy integral, where the weight is local entropy derived from a grey level distribution of local image. The means of this objective function have a multiplicative facto...
Source: Computational and Mathematical Methods in Medicine - December 29, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Predicting Outcomes in Emergency Medical Admissions Using a Laboratory Only Nomogram.
Conclusion: A nomogram to illustrate and explain the prognostic factors underlying an Acute Illness Severity Score system is described. PMID: 29270210 [PubMed - in process] (Source: Computational and Mathematical Methods in Medicine)
Source: Computational and Mathematical Methods in Medicine - December 23, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Research on Gastroesophageal Reflux Disease Based on Dynamic Features of Ambulatory 24-Hour Esophageal pH Monitoring.
Authors: Liu S, Xu M, Yang J, Qi H, He F, Zhao X, Zhou P, Zhang L, Ming D Abstract Ambulatory 24-hour esophageal pH monitoring has been considered as the gold standard for diagnosing gastroesophageal reflux disease (GERD), and in clinical application, static parameters are widely used, such as DeMeester score. However, a shortcoming of these static variables is their relatively high false negative rate and long recording time required. They may be falsely labeled as nonrefluxers and not appropriately treated. Therefore, it is necessary to seek more accurate and objective parameters to detect and quantify GERD. This...
Source: Computational and Mathematical Methods in Medicine - December 23, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Posterior Estimates of Dynamic Constants in HIV Transmission Modeling.
Authors: Chen Y, Dale R, He H, Le QT Abstract In this paper, we construct a linear differential system in both continuous time and discrete time to model HIV transmission on the population level. The main question is the determination of parameters based on the posterior information obtained from statistical analysis of the HIV population. We call these parameters dynamic constants in the sense that these constants determine the behavior of the system in various models. There is a long history of using linear or nonlinear dynamic systems to study the HIV population dynamics or other infectious diseases. Nevertheles...
Source: Computational and Mathematical Methods in Medicine - December 20, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Periodically Pulsed Immunotherapy in a Mathematical Model of Tumor, CD4+ T Cells, and Antitumor Cytokine Interactions.
Authors: Wei HC, Yu JL, Hsu CY Abstract Immunotherapy is one of the most recent approaches for controlling and curing malignant tumors. In this paper, we consider a mathematical model of periodically pulsed immunotherapy using CD4+ T cells and an antitumor cytokine. Mathematical analyses are performed to determine the threshold of a successful treatment. The interindividual variability is explored by one-, two-, and three-parameter bifurcation diagrams for a nontreatment case. Numerical simulation conducted in this paper shows that (i) the tumor can be regulated by administering CD4+ T cells alone in a patient with...
Source: Computational and Mathematical Methods in Medicine - December 20, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Image Fusion of CT and MR with Sparse Representation in NSST Domain.
Authors: Qiu C, Wang Y, Zhang H, Xia S Abstract Multimodal image fusion techniques can integrate the information from different medical images to get an informative image that is more suitable for joint diagnosis, preoperative planning, intraoperative guidance, and interventional treatment. Fusing images of CT and different MR modalities are studied in this paper. Firstly, the CT and MR images are both transformed to nonsubsampled shearlet transform (NSST) domain. So the low-frequency components and high-frequency components are obtained. Then the high-frequency components are merged using the absolute-maximum rule...
Source: Computational and Mathematical Methods in Medicine - December 20, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

A Hybrid Wavelet-Based Method for the Peak Detection of Photoplethysmography Signals.
Authors: Li S, Jiang S, Jiang S, Wu J, Xiong W, Diao S Abstract The noninvasive peripheral oxygen saturation (SpO2) and the pulse rate can be extracted from photoplethysmography (PPG) signals. However, the accuracy of the extraction is directly affected by the quality of the signal obtained and the peak of the signal identified; therefore, a hybrid wavelet-based method is proposed in this study. Firstly, we suppressed the partial motion artifacts and corrected the baseline drift by using a wavelet method based on the principle of wavelet multiresolution. And then, we designed a quadratic spline wavelet modulus maxi...
Source: Computational and Mathematical Methods in Medicine - December 20, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

A Structure Design Method for Reduction of MRI Acoustic Noise.
Authors: Nan J, Zong N, Chen Q, Zhang L, Zheng Q, Xia Y Abstract The acoustic problem of the split gradient coil is one challenge in a Magnetic Resonance Imaging and Linear Accelerator (MRI-LINAC) system. In this paper, we aimed to develop a scheme to reduce the acoustic noise of the split gradient coil. First, a split gradient assembly with an asymmetric configuration was designed to avoid vibration in same resonant modes for the two assembly cylinders. Next, the outer ends of the split main magnet were constructed using horn structures, which can distribute the acoustic field away from patient region. Finally, a ...
Source: Computational and Mathematical Methods in Medicine - December 15, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Interactive K-Means Clustering Method Based on User Behavior for Different Analysis Target in Medicine.
Authors: Lei Y, Yu D, Bin Z, Yang Y Abstract Clustering algorithm as a basis of data analysis is widely used in analysis systems. However, as for the high dimensions of the data, the clustering algorithm may overlook the business relation between these dimensions especially in the medical fields. As a result, usually the clustering result may not meet the business goals of the users. Then, in the clustering process, if it can combine the knowledge of the users, that is, the doctor's knowledge or the analysis intent, the clustering result can be more satisfied. In this paper, we propose an interactive K-means cluste...
Source: Computational and Mathematical Methods in Medicine - December 13, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Advanced Image Enhancement Method for Distant Vessels and Structures in Capsule Endoscopy.
Authors: Rukundo O, Pedersen M, Hovde Ø Abstract This paper proposes an advanced method for contrast enhancement of capsule endoscopic images, with the main objective to obtain sufficient information about the vessels and structures in more distant (or darker) parts of capsule endoscopic images. The proposed method (PM) combines two algorithms for the enhancement of darker and brighter areas of capsule endoscopic images, respectively. The half-unit weighted-bilinear algorithm (HWB) proposed in our previous work is used to enhance darker areas according to the darker map content of its HSV's component V. Enha...
Source: Computational and Mathematical Methods in Medicine - December 13, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

A Cross-Lingual Mobile Medical Communication System Prototype for Foreigners and Subjects with Speech, Hearing, and Mental Disabilities Based on Pictograms.
Authors: Wołk K, Wołk A, Glinkowski W Abstract People with speech, hearing, or mental impairment require special communication assistance, especially for medical purposes. Automatic solutions for speech recognition and voice synthesis from text are poor fits for communication in the medical domain because they are dependent on error-prone statistical models. Systems dependent on manual text input are insufficient. Recently introduced systems for automatic sign language recognition are dependent on statistical models as well as on image and gesture quality. Such systems remain in early development and are based mo...
Source: Computational and Mathematical Methods in Medicine - December 13, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Measuring Coupling of Rhythmical Time Series Using Cross Sample Entropy and Cross Recurrence Quantification Analysis.
Authors: McCamley J, Denton W, Lyden E, Yentes JM Abstract The aim of this investigation was to compare and contrast the use of cross sample entropy (xSE) and cross recurrence quantification analysis (cRQA) measures for the assessment of coupling of rhythmical patterns. Measures were assessed using simulated signals with regular, chaotic, and random fluctuations in frequency, amplitude, and a combination of both. Biological data were studied as models of normal and abnormal locomotor-respiratory coupling. Nine signal types were generated for seven frequency ratios. Fifteen patients with COPD (abnormal coupling) and...
Source: Computational and Mathematical Methods in Medicine - December 6, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Corrigendum to "Comparative Sensitivity Analysis of Muscle Activation Dynamics".
Corrigendum to "Comparative Sensitivity Analysis of Muscle Activation Dynamics". Comput Math Methods Med. 2017;2017:6752731 Authors: Rockenfeller R, Günther M, Schmitt S, Götz T Abstract [This corrects the article DOI: 10.1155/2015/585409.]. PMID: 29177003 [PubMed - in process] (Source: Computational and Mathematical Methods in Medicine)
Source: Computational and Mathematical Methods in Medicine - November 29, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Deep Convolutional Neural Networks for Classifying Body Constitution Based on Face Image.
Authors: Huan EY, Wen GH, Zhang SJ, Li DY, Hu Y, Chang TY, Wang Q, Huang BL Abstract Body constitution classification is the basis and core content of traditional Chinese medicine constitution research. It is to extract the relevant laws from the complex constitution phenomenon and finally build the constitution classification system. Traditional identification methods have the disadvantages of inefficiency and low accuracy, for instance, questionnaires. This paper proposed a body constitution recognition algorithm based on deep convolutional neural network, which can classify individual constitution types accordin...
Source: Computational and Mathematical Methods in Medicine - November 29, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Construction of an miRNA-Regulated Pathway Network Reveals Candidate Biomarkers for Postmenopausal Osteoporosis.
Authors: Shao M Abstract We aimed to identify risk pathways for postmenopausal osteoporosis (PMOP) via establishing an microRNAs- (miRNA-) regulated pathway network (MRPN). Firstly, we identified differential pathways through calculating gene- and pathway-level statistics based on the accumulated normal samples using the individual pathway aberrance score (iPAS). Significant pathways based on differentially expressed genes (DEGs) using DAVID were extracted, followed by identifying the common pathways between iPAS and DAVID methods. Next, miRNAs prediction was implemented via calculating TargetScore values with prec...
Source: Computational and Mathematical Methods in Medicine - November 23, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Numerical Investigation of Pulse Wave Propagation in Arteries Using Fluid Structure Interaction Capabilities.
Authors: Elkenani H, Al-Bahkali E, Souli M Abstract The aim of this study is to present a reliable computational scheme to serve in pulse wave velocity (PWV) assessment in large arteries. Clinicians considered it as an indication of human blood vessels' stiffness. The simulation of PWV was conducted using a 3D elastic tube representing an artery. The constitutive material model specific for vascular applications was applied to the tube material. The fluid was defined with an equation of state representing the blood material. The onset of a velocity pulse was applied at the tube inlet to produce wave propagation. Th...
Source: Computational and Mathematical Methods in Medicine - November 19, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Pairwise Multiple Comparison Adjustment Procedure for Survival Functions with Right-Censored Data.
Authors: Colak E, Ozen H, Emir B, Oner S Abstract The aim of this study is to propose a new pairwise multiple comparison adjustment procedure based on Genz's numerical computation of probabilities from a multivariate normal distribution. This method is applied to the results of two-sample log-rank and weighted log-rank statistics where the survival data contained right-censored observations. We conducted Monte Carlo simulation studies not only to evaluate the familywise error rate and power of the proposed procedure but also to compare the procedure with conventional methods. The proposed method is also applied to ...
Source: Computational and Mathematical Methods in Medicine - November 12, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Hemoglobin-Dilution Method: Effect of Measurement Errors on Vascular Volume Estimation.
This study uses a "Monte Carlo" approach to determine the distribution of these errors. The finding was that these errors could be closely approximated with a log-normal distribution that can be parameterized by a geometric mean (X) and a dispersion factor (S). When the ratio of successive Hb concentrations is used to estimate blood volume, normally distributed hemoglobin measurement errors tend to produce exponentially higher values of X and S as the SD of the measurement error increases. The longer tail of the distribution to the right could produce much greater overestimations than would be expected from the S...
Source: Computational and Mathematical Methods in Medicine - November 10, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Modelling Risk to US Military Populations from Stopping Blanket Mandatory Polio Vaccination.
Conclusion: Risk-based immunization driven by deployment to polio-endemic regions is sufficient to prevent transmission among both deployed and nondeployed US military populations. PMID: 29104608 [PubMed - in process] (Source: Computational and Mathematical Methods in Medicine)
Source: Computational and Mathematical Methods in Medicine - November 8, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Biomarker MicroRNAs for Diagnosis of Oral Squamous Cell Carcinoma Identified Based on Gene Expression Data and MicroRNA-mRNA Network Analysis.
Authors: Zhang H, Li T, Zheng L, Huang X Abstract Oral squamous cell carcinoma is one of the most malignant tumors with high mortality rate worldwide. Biomarker discovery is critical for early diagnosis and precision treatment of this disease. MicroRNAs are small noncoding RNA molecules which often regulate essential biological processes and are good candidates for biomarkers. By integrative analysis of both the cancer-associated gene expression data and microRNA-mRNA network, miR-148b-3p, miR-629-3p, miR-27a-3p, and miR-142-3p were screened as novel diagnostic biomarkers for oral squamous cell carcinoma based on t...
Source: Computational and Mathematical Methods in Medicine - November 5, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Predictive Modelling Based on Statistical Learning in Biomedicine.
Authors: Gefeller O, Hofner B, Mayr A, Waldmann E PMID: 29093744 [PubMed - in process] (Source: Computational and Mathematical Methods in Medicine)
Source: Computational and Mathematical Methods in Medicine - November 3, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Modelling and Optimal Control of Typhoid Fever Disease with Cost-Effective Strategies.
Authors: Tilahun GT, Makinde OD, Malonza D Abstract We propose and analyze a compartmental nonlinear deterministic mathematical model for the typhoid fever outbreak and optimal control strategies in a community with varying population. The model is studied qualitatively using stability theory of differential equations and the basic reproductive number that represents the epidemic indicator is obtained from the largest eigenvalue of the next-generation matrix. Both local and global asymptotic stability conditions for disease-free and endemic equilibria are determined. The model exhibits a forward transcritical bifur...
Source: Computational and Mathematical Methods in Medicine - October 31, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

The Applications of Finite Element Analysis in Proximal Humeral Fractures.
Authors: Ye Y, You W, Zhu W, Cui J, Chen K, Wang D Abstract Proximal humeral fractures are common and most challenging, due to the complexity of the glenohumeral joint, especially in the geriatric population with impacted fractures, that the development of implants continues because currently the problems with their fixation are not solved. Pre-, intra-, and postoperative assessments are crucial in management of those patients. Finite element analysis, as one of the valuable tools, has been implemented as an effective and noninvasive method to analyze proximal humeral fractures, providing solid evidence for managem...
Source: Computational and Mathematical Methods in Medicine - October 31, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Anisotropy Influences on the Drug Delivery Mechanisms by Means of Joint Invariant Functions.
Authors: Cioca G, Bacaita ES, Agop M, Lupascu Ursulescu C Abstract In the frame of Higuchi's type functionality, this paper presents the anisotropy influences on the drug delivery mechanisms through the joint invariant functions to the simultaneous actions of the two SL(2R) isomorphic groups. Then, a new equation for drug delivery mechanism, independent of the type of polymer matrix and/or drug, is proposed. PMID: 29081830 [PubMed - in process] (Source: Computational and Mathematical Methods in Medicine)
Source: Computational and Mathematical Methods in Medicine - October 31, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Stochastic Models of Emerging Infectious Disease Transmission on Adaptive Random Networks.
We presented adaptive random network models to describe human behavioral change during epidemics and performed stochastic simulations of SIR (susceptible-infectious-recovered) epidemic models on adaptive random networks. The interplay between infectious disease dynamics and network adaptation dynamics was investigated in regard to the disease transmission and the cumulative number of infection cases. We found that the cumulative case was reduced and associated with an increasing network adaptation probability but was increased with an increasing disease transmission probability. It was found that the topological changes of...
Source: Computational and Mathematical Methods in Medicine - October 29, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Pathway Interaction Network Analysis Identifies Dysregulated Pathways in Human Monocytes Infected by Listeria monocytogenes.
Authors: Fan W, Zhou Y, Li H Abstract In our study, we aimed to extract dysregulated pathways in human monocytes infected by Listeria monocytogenes (LM) based on pathway interaction network (PIN) which presented the functional dependency between pathways. After genes were aligned to the pathways, principal component analysis (PCA) was used to calculate the pathway activity for each pathway, followed by detecting seed pathway. A PIN was constructed based on gene expression profile, protein-protein interactions (PPIs), and cellular pathways. Identifying dysregulated pathways from the PIN was performed relying on seed...
Source: Computational and Mathematical Methods in Medicine - September 29, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Hamiltonian Analysis of Subcritical Stochastic Epidemic Dynamics.
Authors: Worden L, Schwartz IB, Bianco S, Ackley SF, Lietman TM, Porco TC Abstract We extend a technique of approximation of the long-term behavior of a supercritical stochastic epidemic model, using the WKB approximation and a Hamiltonian phase space, to the subcritical case. The limiting behavior of the model and approximation are qualitatively different in the subcritical case, requiring a novel analysis of the limiting behavior of the Hamiltonian system away from its deterministic subsystem. This yields a novel, general technique of approximation of the quasistationary distribution of stochastic epidemic and bi...
Source: Computational and Mathematical Methods in Medicine - September 23, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Effect of Rainfall for the Dynamical Transmission Model of the Dengue Disease in Thailand.
Authors: Chanprasopchai P, Pongsumpun P, Tang IM Abstract The SEIR (Susceptible-Exposed-Infected-Recovered) model is used to describe the transmission of dengue virus. The main contribution is determining the role of the rainfall in Thailand in the model. The transmission of dengue disease is assumed to depend on the nature of the rainfall in Thailand. We analyze the dynamic transmission of dengue disease. The stability of the solution of the model is analyzed. It is investigated by using the Routh-Hurwitz criteria. We find two equilibrium states: a disease-free state and an endemic equilibrium state. The basic rep...
Source: Computational and Mathematical Methods in Medicine - September 22, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Mechanistic Model for Cancer Growth and Response to Chemotherapy.
Authors: Simbawa E Abstract Cancer treatment has developed over the years; however not all patients respond to this treatment, and therefore further research is needed. In this paper, we employ mathematical modeling to understand the behavior of cancer and its interaction with therapy. We study a drug delivery and drug-cell interaction model along with cell proliferation. Due to the fact that cancer cells grow when there are enough nutrients and oxygen, proliferation can be a barrier against a response to therapy. To understand the effect of this factor, we perform numerical simulations of the model for different v...
Source: Computational and Mathematical Methods in Medicine - September 22, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Sensitivity Analysis of the Integral Quality Monitoring System ® Using Monte Carlo Simulation.
Sensitivity Analysis of the Integral Quality Monitoring System® Using Monte Carlo Simulation. Comput Math Methods Med. 2017;2017:7025281 Authors: Oderinde OM, du Plessis FCP Abstract The Integral Quality Monitoring (IQM) System is a real-time beam output verifying system that validates the integrity and accuracy of patient treatment plan (TP) data during radiation treatment. The purpose of this study was to evaluate the sensitivity of the IQM to errors in segment using EGSnrc/BEAMnrc Monte Carlo (MC) codes. Sensitivity analysis (SA) techniques were applied to study the significance of small alterat...
Source: Computational and Mathematical Methods in Medicine - September 22, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Segmentation of Left and Right Ventricles in Cardiac MRI Using Active Contours.
Authors: Soomro S, Akram F, Munir A, Lee CH, Choi KN Abstract Segmentation of left and right ventricles plays a crucial role in quantitatively analyzing the global and regional information in the cardiac magnetic resonance imaging (MRI). In MRI, the intensity inhomogeneity and weak or blurred object boundaries are the problems, which makes it difficult for the intensity-based segmentation methods to properly delineate the regions of interests (ROI). In this paper, a hybrid signed pressure force function (SPF) is proposed, which yields both local and global image fitted differences in an additive fashion. A characte...
Source: Computational and Mathematical Methods in Medicine - September 22, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Dendritic Immunotherapy Improvement for an Optimal Control Murine Model.
Authors: Rangel-Reyes JC, Chimal-Eguía JC, Castillo-Montiel E Abstract Therapeutic protocols in immunotherapy are usually proposed following the intuition and experience of the therapist. In order to deduce such protocols mathematical modeling, optimal control and simulations are used instead of the therapist's experience. Clinical efficacy of dendritic cell (DC) vaccines to cancer treatment is still unclear, since dendritic cells face several obstacles in the host environment, such as immunosuppression and poor transference to the lymph nodes reducing the vaccine effect. In view of that, we have created a m...
Source: Computational and Mathematical Methods in Medicine - September 17, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Products of Compartmental Models in Epidemiology.
Authors: Worden L, Porco TC Abstract We show that many structured epidemic models may be described using a straightforward product structure in this paper. Such products, derived from products of directed graphs, may represent useful refinements including geographic and demographic structure, age structure, gender, risk groups, or immunity status. Extension to multistrain dynamics, that is, pathogen heterogeneity, is also shown to be feasible in this framework. Systematic use of such products may aid in model development and exploration, can yield insight, and could form the basis of a systematic approach to numeri...
Source: Computational and Mathematical Methods in Medicine - September 14, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Computational and Mathematical Methods to Estimate the Basic Reproduction Number and Final Size for Single-Stage and Multistage Progression Disease Models for Zika with Preventative Measures.
We present new mathematical models that include the impact of using selected preventative measures such as insecticide treated nets (ITN) in controlling or ameliorating the spread of the Zika virus. For these models, we derive the basic reproduction number and sharp estimates for the final size relation. We first present a single-stage model which is later extended to a new multistage model for Zika that incorporates more realistic incubation stages for both the humans and vectors. For each of these models, we derive a basic reproduction number and a final size relation estimate. We observe that the basic reproduction numb...
Source: Computational and Mathematical Methods in Medicine - September 13, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

A Novel Dynamic Model Describing the Spread of the MERS-CoV and the Expression of Dipeptidyl Peptidase 4.
Authors: Tang S, Ma W, Bai P Abstract The Middle East respiratory syndrome (MERS) coronavirus, a newly identified pathogen, causes severe pneumonia in humans. MERS is caused by a coronavirus known as MERS-CoV, which attacks the respiratory system. The recently defined receptor for MERS-CoV, dipeptidyl peptidase 4 (DPP4), is generally expressed in endothelial and epithelial cells and has been shown to be present on cultured human nonciliated bronchiolar epithelium cells. In this paper, a class of novel four-dimensional dynamic model describing the infection of MERS-CoV is given, and then global stability of the equi...
Source: Computational and Mathematical Methods in Medicine - September 13, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

Several Indicators of Critical Transitions for Complex Diseases Based on Stochastic Analysis.
Authors: Wang G, Li Y, Zou X Abstract Many complex diseases (chronic disease onset, development and differentiation, self-assembly, etc.) are reminiscent of phase transitions in a dynamical system: quantitative changes accumulate largely unnoticed until a critical threshold is reached, which causes abrupt qualitative changes of the system. Understanding such nonlinear behaviors is critical to dissect the multiple genetic/environmental factors that together shape the genetic and physiological landscape underlying basic biological functions and to identify the key driving molecules. Based on stochastic differential e...
Source: Computational and Mathematical Methods in Medicine - August 25, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research

A Multicriteria Approach to Find Predictive and Sparse Models with Stable Feature Selection for High-Dimensional Data.
Authors: Bommert A, Rahnenführer J, Lang M Abstract Finding a good predictive model for a high-dimensional data set can be challenging. For genetic data, it is not only important to find a model with high predictive accuracy, but it is also important that this model uses only few features and that the selection of these features is stable. This is because, in bioinformatics, the models are used not only for prediction but also for drawing biological conclusions which makes the interpretability and reliability of the model crucial. We suggest using three target criteria when fitting a predictive model to a high...
Source: Computational and Mathematical Methods in Medicine - August 25, 2017 Category: Statistics Tags: Comput Math Methods Med Source Type: research