Knee Arthroplasty Incidence Rate vs. Revision of Knee Arthroplasty and Its Associated Comorbidities in Colombia

Introduction: Total knee arthroplasty (TKA) has been established as a transformative solution in the treatment of advanced degenerative diseases of the knee, such as osteoarthritis, rheumatoid arthritis, and posttraumatic arthritis. In this sense, TKA surgery, which seeks to replace the damaged joint with prosthetic components, has proven to be highly effective in relieving pain, improving joint function, and, ultimately, significantly increasing patients’ quality of life. The present study describes the TKA and revision knee arthroplasty (RKA) rates and, identifies the associated co morbidities in the Colombian context. Methods: A retrospective cohort study was carried out. It describes demographic and clinical characteristics between two groups of patients, TKA or RKA, and its association with mortality at 30 days, 90 days, or one year after the intervention. Results: The incidence rate of the population undergoing TKA was approximately 11.71 cases per 100,000 inhabitants. Furthermore, the incidence rate for revision knee arthroplasty (RKA) procedures in the same period was around 0.96 per 100,000 inhabitants. In both groups at 30 days postoperatively, a total mortality rate of 0.09%was recorded. When the follow-up was extended to 90 days, it increased to 0.15%;at one year postoperatively, it rose to 0.88%. Conclusion: Mortality after surgery was low in Colombia in 2019. Although RKA is a beneficial procedure, in certain circumstances, it was noted that it carries a higher risk compared to primary TKA. Our results emphasize the importance of careful evaluation of co morbidities and risk factors in patients undergoing these surgical procedures. The application of quality-of-life questionnaires should be considered in future studies on effectiveness and mortality for TKA and RKA in our country.

GLOBAL STABILITY OF SIRS EPIDEMIC MODELS WITH A CLASS OF NONLINEAR INCIDENCE RATES AND DISTRIBUTED DELAYS

In this article, we establish the global asymptotic stability of a disease-free equilibrium and an endemic equilibrium of an SIRS epidemic model with a class of nonlin- ear incidence rates and distributed delays. By using strict monotonicity of the incidence function and constructing a Lyapunov functional, we obtain sufficient conditions under which the endemic equilibrium is globally asymptotically stable. When the nonlinear inci- dence rate is a saturated incidence rate, our result provides a new global stability condition for a small rate of immunity loss.

TWO DIFFERENTIAL INFECTIVITY EPIDEMIC MODELS WITH NONLINEAR INCIDENCE RATE

This paper considers two differential infectivity（DI） epidemic models with a nonlinear incidence rate and constant or varying population size. The models exhibits two equilibria, namely., a disease-free equilibrium O and a unique endemic equilibrium. If the basic reproductive number σ is below unity,O is globally stable and the disease always dies out. If σ〉1, O is unstable and the sufficient conditions for global stability of endemic equilibrium are derived. Moreover,when σ〈 1 ,the local or global asymptotical stability of endemic equilibrium for DI model with constant population size in n-dimensional or two-dimensional space is obtained.

Stability Analysis of SIQS Epidemic Model with Saturated Incidence Rate

A SIQS epidemic model with saturated incidence rate is studied. Two equilibrium points exist for the system, disease-free and endemic equilibrium. The stability of the disease-free equilibrium and endemic equilibrium exists when the basic reproduction number R0, is less or greater than unity respectively. The global stability of the disease-free and endemic equilibrium is proved using Lyapunov functions and Poincare-Bendixson theorem plus Dulac’s criterion respectively.

Dynamics of a Nonautonomous SIR Model with Time-Varying Impulsive Release and General Nonlinear Incidence Rate in a Polluted Environment

In a polluted environment, considering the biological population infected with a kind of disease and hunted by human beings, we formulate a nonautonomous SIR population-epidemic model with time-varying impulsive release and general nonlinear incidence rate and investigate dynamical behaviors of the model. Under the reasonable assumptions, the sufficient conditions which guarantee the globally attractive of the disease-free periodic solution and the permanence of the infected fish are established, that is, the infected fish dies out if , whereas the disease persists if . To substantiate our theoretical results, extensive numerical simulations are performed for a hypothetical set of parameter values.

Implication of Reported Viral Hepatitis Incidence Rate Change in Hubei Province, China, between 2004-2010

This study examined the change of reported incidence rate for viral hepatitis in Hubei province, China, between 2004 to 2010 to provide scientific evidence for viral hepatitis control. Reported viral hepatitis infection cases were queried from Centre for Disease Control of Hubei Province, China. The incidence of viral hepatitis A decreased steadily across the study period. Viral hepatitis B composed 85% of the viral hepatitis cases. When reported incidence rates for chronic hepatitis B increased, the rates of acute and unclassified cases dropped from 2005 to 2010. The reported viral hepatitis B incidence rate for males was around 1.5-2 times higher than for females. The average annual percentage change of reported viral hepatitis B incidence rates was 4%. The same index for viral hepatitis C was 28%. The reported viral hepatitis B incidence rate of people under 20 years old declined over the period. This decrease was mainly attributed to the recent implementation of vaccination plan. Reported incidence rate of viral hepatitis E also rose in those years. Having a better understanding on reported incidence rates of the present surveillance system is important for developing strategies for further prevention of viral hepatitis. In addition, the data showed that a surveillance system that differentiates new and former infected cases will be more effective in providing evidence for disease control.

Global Analysis of an SEIR Epidemic Model with Nonlinear Incidence Rates

In this paper,an SEIR model with nonlinear incidence rates are studied.The basic reproduction number R_0 characterizes the disease transmission dynamics: if R_0≤ 1,the disease-free equilibrium is globally asymptotically stable and the disease always dies out,if R_0> 1 then there is a unique endemic equilibrium which is globally asymptotically stable and the disease persists.

National Breast Cancer Mortality and Incidence Rates According to the Human Development Index: An Ecological Study

Background: This study aimed to identify the role of human development index (HDI) in the incidence and mortality rates of breast cancer (BC) worldwide. Methods: Data on the age-standardized incidence and mortality rates of BC for 184 countries were obtained from the GLOBOCAN. Data about the HDI and other indices were obtained from the World Bank Report 2013. Linear regression model was used for assessment the effect of HDI on BC occurrence rates. Results: In 2012, BCs were estimated to have affected a total of 1,671,149 individuals (crude rate: 47.8 per 100,000 individuals), and caused 521,907 deaths worldwide (crude rate: 14.7 per 100,000 individuals). Nearly half of total female BC cases (46.3%) with the highest risk of incidence (age-standardized Rate (ASR): 128 per 100,000) had occurred in very high HDI regions. The most proportion of the mortality burden was in low HDI and medium HDI areas. Linear regression analyses showed a direct significant correlation between the incidence of BC and HDI at the global level (B = 104.5, P < 0.001). The mortality rate of BC was not significantly associated with HDI (B = 3.26, P = 0.160). Conclusion: Our study showed that the burden of female BC is enormous in very high HDI and low HID regions. Targeted interventions have the ability to reduce this number significantly through resource-dependent interventions. Moreover, further reductions in mortality could be brought about by increasing access to curative treatment for patients with BC.

A Novel Analysis Approach of Uniform Persistence for an Epidemic Model with Quarantine and Standard Incidence Rate

Inspired by the transmission characteristics of the coronavirus disease 2019(COVID-19),an epidemic model with quarantine and standard incidence rate is first developed,then a novel analysis approach is proposed for finding the ultimate lower bound of the number of infected individuals,which means that the epidemic is uniformly persistent if the control reproduction number R_(c)>1.This approach can be applied to the related biomat hem at ical models,and some existing works can be improved by using that.In addition,the infection-free equilibrium V^(0)of the model is locally asymptotically stable(LAS)if R_(c)<1 and linearly stable if R_(c)=1;while V^(0)is unstable if R_(c)>1.

The effect of the fear factor on the dynamics of an eco-epidemiological system with standard incidence rate

In order to protect endangered prey,ecologists suggest introducing parasites into predators which have achieved the expected goal in practice.Then how to explain the inherent mechanism and validate the effectiveness of this approach theoretically?In response to this question,we propose an eco-epidemiological system with the standard incidence rate and the anti-predator behavior in this paper,where the predator population is infected by parasites.We show the existence and local stability of equilibria for the system,and verify the occurrence of Hopf bifurcation.Theoretical and numerical results suggest that the fear effect reduces the density of the predator population but has no effect on the density of prey population.In addition,the cost of fear may not only break the stability of the equilibrium of the system,but also induce the equilibrium to change from unstable to stable.Based on the theoretical analysis,we confirm that introducing parasites into the predator population is an effective method to protect endangered prey.

Bifurcation analysis of an SIS epidemic model with a generalized non-monotonic and saturated incidence rate

In this paper,a new generalized non-monotonic and saturated incidence rate was introduced into a susceptible-infected-susceptible(SIS)epidemic model to account for inhibitory effect and crowding effect.The dynamic properties of the model were studied by qualitative theory and bifurcation theory.It is shown that when the infuence of psychological factors is large,the model has only disease-free equilibrium point,and this disease-free equilibrium point is globally asymptotically stable;when the influence of psychological factors is small,for some parameter conditions,the model has a unique endemic equilibrium point,which is a cusp point of co-dimension two,and for other parameter conditions the model has two endemic equilibrium points,one of which could be weak focus or center.In addition,the results of the model undergoing saddle-node bifurcation,Hopf bifurcation and Bogdanov-Takens bifurcation as the parameters vary were also proved.These results shed light on the impact of psychological behavior of susceptible people on the disease transmission.

Analysis of within-host CHIKV dynamics models with general incidence rate

In this paper we study the stability analysis of two within-host Chikungunya virus （CHIKV） dynamics models. The incidence rate between the CHIKV and the uninfected mouocytes is modeled by a general nonlinear function. The second model considers two types of infected monocytes （i） latently infected monocytes which do not generate CHIKV and （ii） actively infected monocytes which produce the CHIKV particles. Sufficient conditions are found which guarantee the global stability of the positive steady states. Using the Lyapunov function, we established the global stability of the steady states of the models. The theoretical results are confirmed by numerical simulations.

An age-structured epidemic model with waning immunity and general nonlinear incidence rate

In this paper, a susceptible-vazcinated-exposed-infectious-recovered epidemic model with waning immunity and continuous age structures in vaccinated, exposed and infectious classes has been formulated. By using the Fluctuation lemma and the approach of Lyapunov functionals, we establish a threshold dynamics completely determined by the basic reproduction number. When the basic reproduction number is less than one, the disease-free steady state is globally asymptotically stable, and otherwise the endemic steady state is globally asymptotically stable.

Dynamical analysis of a reaction-diffusion SEI epidemic model with nonlinear incidence rate

In this paper,a reaction-diffusion SEI epidemic model with nonlinear incidence rate is proposed.The well-posedness of solutions is studied,including the existence of positive and unique classical solution and the existence and the ultimate boundedness of global solutions.The basic reproduction numbers are given in both heterogeneous and homogeneous environments.For spatially heterogeneous environment,by the comparison principle of the diffusion system,the infection-free steady state is proved to be globally asymptotically stable if R_(0)<1,if R_(0)>1,the system will be persistent and admit at least one positive steady state.For spatially homogenous environment,by constructing a Lyapunov function,the infect ion-free steady state is proved to be globally asymptotically stable if,R_(0)<1,and then the unique positive steady state is achieved and is proved to be globally asymptotically stable if R_(0)>1.Finally,two examples are given via numerical simulations,and then some control strategies are also presented by the sensitive analysis.

Dynamical behavior of a stochastic multigroup staged-progression HIV model with saturated incidence rate and higher-order perturbations

In this paper,we analyze a higher-order stochastically perturbed multigroup staged-progression model for the transmission of HlV with saturated incidence rate.We obtainsufficient conditions for the existence and uniqueness of an ergodic stationary distribu-tion of positive solutions to the system by establishing a suitable stochastic Lyapunovfunction.In addition,we make up adequate conditions for complete eradication and wip-ing out the infectious disease.In a biological interpretation,the existence of a stationarydistribution implies that the disease will prevail and persist in the long term.Finally,examples and numerical simulations are introduced to validate our theoretical results.

Chaos detection in SIR model with modified Beddington–De Angelis type incidence rate and saturated treatment

In this paper, we construct an SIR epidemic model with a modified Beddington–DeAngelis type incidence rate and saturated treatment rate. We modify the incidence rateto incorporate the isolation of infected individuals after detection, and separation of somesusceptible individuals from the rest to avoid the infection, without an increase in thenumber of classes. We find that the system has a unique disease-free equilibrium (DFE)which is locally asymptotically stable when the reproduction number is less than unity.The multiple endemic equilibria may exist irrespective of the basic reproduction number.The existence of bistability is encountered. Supercritical transcritical (forward), as wellas subcritical transcritical (backward) bifurcation, may occur at R0 = 1 where contactrate, β = β∗ acts as the bifurcation parameter. Therefore, DFE need not be globallystable. The conditions for the existence of Andronov–Hopf bifurcation are deduced withmaximum treatment capacity, c = c0 as the bifurcation parameter. The impacts of isolation of confirmed infected cases and separation of some susceptible from rest are studiednumerically as well as the effect of saturation in treatment. The existence of chaoticbehavior is deduced by showing the maximum Lyapunov exponent to be positive as wellas the sensitivity to initial conditions. The computation of the Kalpan–Yorke dimensionto be fractional confirms the existence of fractal-type strange attractor. The positiveKolmogorov–Sinai entropy further strengthens the claim of the existence of chaos.

Trends of incidence and mortality rates of stroke from 1983 to 2000 in Hanzhong rural population

Objective: To explore the trends of incidence and mortality rates of stroke in Hanzhong rural population. Methods: Acting as the WHO MONICA project. Results: The incidence rate of stroke was 152.9/100 000. There was decline trend in male(P<0.05). The mortality rate of stroke was 115.9/100 000. There was no significant decline trend during 18-year period (P<0.05). The incidence and mortality rates of stroke of male were higher than those of female(P<0.05).The incidence and mortality rates were all increased with age(P<0.01). Conclusion: It must stick to the long- term prevention measures to decrease incidence rate, and improve the condition of medical treatment to reduce the mortality rate in rural population.

ANALYSIS OF AN EPIDEMIC MODEL WITH CROWLEY-MARTIN INCIDENCE RATE AND HOLLING TYPE Ⅱ TREATMENT

We propose an epidemic model consisting five compartments within a total population with Crowley-Martin incidence rate and Holling type Ⅱ treatment,where total population is separated by the susceptible, the vaccinated, the exposed, the infected and the removed in this paper. We firstly prove that the epidemic model admits a unique global positive solution by contradiction. We then find out that diseases tend to extinction provided that the basic reproduction number is less than one. Moreover, the sufficient conditions of persistence for infectious diseases are obtained by constructing suitable Lyapunov functions.

Stability analysis for delayed viral infection model with multitarget cells and general incidence rate

In this paper, the sharp threshold properties of a （2n ＋ 1）-dimensional delayed viral infection model are investigated. This model combines with n classes of uninfected tar- get cells, n classes of infected cells and nonlinear incidence rate h（x,v）. Two kinds of distributed time delays are incorporated into the model to describe the time needed for infection of uninfected target cells and virus replication. Under certain conditions, it is shown that the basic reproduction number is a threshold parameter for the existence of the equilibria, uniform persistence, as well as for global stability of the equilibria of the model.

Evaluation and application of a milk antibody ELISA for assessing the prevalence and incidence of bovine tuberculosis in dairy herds in Hubei Province,China

Bovine tuberculosis(bTB)is a chronic zoonotic disease that is endemic in China.Current in-vitro tests for bTB are mainly based on blood assays.Collection of samples results in some stress to the sampled cattle and associated economic losses for the herd owner.This study was designed to investigate the relationship between milk and serum antibody tests for bTB in dairy cows using 85 cows with milk and corresponding blood samples.Totally 4,395 milk samples were used to assesse the apparent(test)prevalence and incidence of bTB using the milk antibody ELISA.The association between levels of bTB milk antibody and milk quality was also evaluated.Milk and serum antibody tests showed a good correlation with a 87.5%(95%CI:61.7%,98.4)positive agreement and 98.7%(95%CI:95.4,99.8)negative agreement.The animal level lactoprevalence ranged from 0.3%(95%CI:0,1.2)to 33.3%(95%CI:26.6,40.6)in different farms and the incidence rate ranged from 0 head/cow-month(95%CI:0,0.02)to 0.04 head/cow-month(95%CI:0.02,0.07).Twenty percent of sampled farms met the criteria for bTB control in China.The prevalence on large-scale farms was lower(p<0.001)than on small farms.The bTB milk antibody levels had a negative correlation with milk yield and a positive correlation with somatic cell count(SCC),milk protein percentage(MPP)and percentage of total solids(TS).According to this research,milk ELISA could be used as a supplement of blood samples to assist in the surveillance for bTB and for alerting control and eradication of bTB.