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1.
Sensors (Basel) ; 24(11)2024 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-38894477

RESUMO

In the field of armored vehicles, up to 70% of accidents are associated with low levels of situational awareness among the occupants, highlighting the importance of situational awareness in improving task performance. In this study, we explored the mechanisms influencing situational awareness by simulating an armored vehicle driving platform with 14 levels of experimentation in terms of five factors: experience, expectations, attention, the cueing channel, and automation. The experimental data included SART and SAGAT questionnaire scores, eye movement indicators, and electrocardiographic and electrodermal signals. Data processing and analysis revealed the following conclusions: (1) Experienced operators have higher levels of situational awareness. (2) Operators with certain expectations have lower levels of situational awareness. (3) Situational awareness levels are negatively correlated with information importance affiliations and the frequency of anomalous information in non-primary tasks. (4) Dual-channel cues lead to higher levels of situational awareness than single-channel cues. (5) Operators' situational awareness is lower at high automation levels.


Assuntos
Condução de Veículo , Conscientização , Humanos , Conscientização/fisiologia , Adulto , Masculino , Feminino , Atenção/fisiologia , Movimentos Oculares/fisiologia , Eletrocardiografia/métodos , Inquéritos e Questionários , Adulto Jovem , Acidentes de Trânsito/prevenção & controle , Sinais (Psicologia) , Automação , Análise e Desempenho de Tarefas , Automóveis
2.
Medicine (Baltimore) ; 103(24): e38456, 2024 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-38875407

RESUMO

Infective endophthalmitis is an ophthalmic infection that in severe cases can cause complete loss of vision. In children, the defense against infection is low and eye tissue is not fully developed, leading to increased vulnerability to endophthalmitis. Children may be unable to understand the symptoms; thus, developing a method for prevention and treatment of this disease in children is important. Therefore, we analyzed the clinical and pathogenic characteristics of infectious endophthalmitis in children and provided evidence for clinical treatment. The clinical data of 78 children (78 eyes) with infectious endophthalmitis were retrospectively analyzed. The clinical characteristics, pathogen distribution, drug sensitivity, clinical medication, and treatments were summarized and analyzed. In total, 74 (94.87%) had ocular infections caused by trauma and 75 (96.15%) were from rural townships. A total of 108 sterile specimens were examined, with a positive detection rate of 37.04%. The sensitivity rates of Gram-positive cocci and bacilli to vancomycin were 100%. The sensitivity rates of Gram-negative bacilli to ceftazidime, piperacillin/tazobactam, amikacin, gentamicin, ciprofloxacin, and levofloxacin were 100%. Of the 78 patients, 53 (67.95%) received intravitreal injection and 54 (69.23%) underwent vitrectomy. Trauma is the main factor leading to infectious endophthalmitis in children, wherein Gram-positive bacteria are the most common pathogens. Thus, a timely understanding of the pathogen and drug sensitivity is needed. Intravitreal injection and vitrectomy are effective treatments.


Assuntos
Antibacterianos , Endoftalmite , Humanos , Endoftalmite/microbiologia , Endoftalmite/epidemiologia , Endoftalmite/tratamento farmacológico , Estudos Retrospectivos , Criança , Masculino , Feminino , Pré-Escolar , Antibacterianos/uso terapêutico , Lactente , Infecções Oculares Bacterianas/microbiologia , Infecções Oculares Bacterianas/epidemiologia , Adolescente , Testes de Sensibilidade Microbiana , Vitrectomia , Injeções Intravítreas
3.
Ophthalmol Ther ; 13(7): 1909-1924, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38743158

RESUMO

INTRODUCTION: To evaluate the intraocular differences in optical coherence tomography (OCT)-based macular curvature index (MCI) among children with anisomyopia and to investigate the relationship between MCI and the macular microvasculature. METHODS: Fifty-two schoolchildren with anisometropia > 2.00 D were enrolled and underwent comprehensive examinations including cycloplegic refraction, axial length (AL), and swept source OCT/OCT angiography. OCT-based MCIs were determined from horizontal and vertical B-scans by a customized curve fitting model in MATLAB R2022 at 1-mm-, 3-mm-, and 6-mm-diameter circles at fovea. Characteristics and topographic variation of MCI was analyzed, and the relationships with microvascularity and its associated factors were investigated. RESULTS: MCI achieved high reliability and repeatability. There were overall larger MCIs in the more myopic eyes than the less myopic eyes in 1-mm-, 3-mm-, and 6-mm-diameter circles at fovea (all p < 0.001). For the topographic variation, horizontal MCI was significantly greater than vertical MCI (all p < 0.001), and was the largest in 6-mm circle, followed by 3-mm and 1-mm circles. Stronger correlation of horizontal MCI with myopic severity than vertical MCI was found. Partial Pearson's correlation found MCI was negatively associated with deep capillary plexus (DCP) vessel density (p = 0.016). Eyes with a higher MCI in a 6-mm circle were more likely to have longer AL (p < 0.001), lower DCP vessel density (p = 0.037), and thinner choroidal thickness (ChT) (p = 0.045). CONCLUSION: Larger MCI was found in the more myopic eyes of children with anisomyopia and was significantly associated with smaller DCP density, suggesting that MCI was an important indicator of myopia-related retinal microvascularity change, and it could be a valuable metric for myopia assessment in children.

4.
J Invertebr Pathol ; 203: 108072, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38341022

RESUMO

Pathogenic microorganism of silkworm are important factors that threaten the high-quality development of sericulture. Among them, Bombyx mori nucleopolyhedrovirus (BmNPV) caused diseases often lead to frequent outbreaks and high mortality, resulting in huge losses to sericultural industry. Current molecular detection methods for BmNPV require expensive equipment and sikilled technical personnel. As a result, the most commonly detection method for silkworm egg production enterprises involves observing the presence of polyhedra under a microscope. However, this method has low accuracy and sensitivity. There is an urgent need to develop a new detection technology with high sensitivity, high specificity, and applicability for silkworm farms, silkworm egg production enterprises and quarantine departments. In this study, we successfully established the CRISPR/Cas13a BmNPV visualized detection technology by combining Recombinase Polymerase Amplification (RPA) technology and CRISPR/Cas13a system. This technology is based on microplate lateral, flow test strips and portable fluorescence detector. The detection sensitivity can reach up to 1 copies/µL for positive standard plasmid and 1 fg/µL for BmNPV genome in 30-45 min, demonstrating high sensitivity. By detecting silkworm tissues infected with different pathogens, we determined that CRISPR/Cas13a detection technology has good specificity. In summary, the newly established nucleic acid detection technology for BmNPV is characterized by high sensitivity, high specificity, low cost and convenience for visualization. It can be applied in field detection and silkworm egg quality monitory system.


Assuntos
Bombyx , Nucleopoliedrovírus , Animais , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/genética , Nucleopoliedrovírus/genética , Sensibilidade e Especificidade
5.
Medicine (Baltimore) ; 102(44): e35784, 2023 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-37933005

RESUMO

RATIONALE: Phacolytic glaucoma (PLG), a secondary open-angle glaucoma caused by high molecular weight proteins leaking through the capsule of a hypermature cataract. Leakage of liquefied lens cortex behind the posterior capsule is rare. In this paper, we review a case of phacolytic glaucoma in the lens cortex behind posterior capsule. PATIENT CONCERNS: This case report describes a 79-year-old male patient with a 7-year history of progressive blurred vision and a 1-day history of distended in his left eye. He underwent phacoemulsification combined with intraocular lens implantation at our facility 7 years ago. DIAGNOSES: The patient had lower vision (light perception vision) and increased intraocular pressure (IOP) (60 mmHg) in the left eye. Auxiliary inspection found that the left eye had deep anterior chamber depth (around 1 corneal thickness of the peripheral AC angle) as well as vitreous and aqueous humor opacity in the left eye. Combining the clinical symptoms and examinations, we made the diagnosis of PLG in the left eye. INTERVENTIONS: The patient underwent trabeculectomy and extracapsular cataract extraction of the left after a stable ocular condition, during the operation to see that white chyous cortex was visible under the posterior capsule and posterior capsule membrane of the lens was avulsed circularly. OUTCOMES: The postoperative condition was stable. During the follow up of 3 months, the IOP of the left eye was stable without ocular discomfort. LESSONS: This case reported a patient with phacolytic glaucoma in the lens cortex behind posterior capsule who underwent successful surgery, indicating spontaneous capsule rupture can occur in the posterior capsules in PLG and when this situation is detected during the operation, the posterior capsule tearing method can be applied to absorb the lens cortex sticking at the posterior surface of the posterior capsule.


Assuntos
Extração de Catarata , Catarata , Glaucoma de Ângulo Aberto , Glaucoma , Idoso , Humanos , Masculino , Catarata/complicações , Glaucoma/cirurgia , Glaucoma de Ângulo Aberto/cirurgia , Pressão Intraocular
6.
J Math Biol ; 87(4): 62, 2023 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-37736867

RESUMO

Our earlier work in Nguyen et al. (Maximizing metapopulation growth rate and biomass in stream networks. arXiv preprint arXiv:2306.05555 , 2023) shows that concentrating resources on the upstream end tends to maximize the total biomass in a metapopulation model for a stream species. In this paper, we continue our research direction by further considering a Lotka-Volterra competition patch model for two stream species. We show that the species whose resource allocations maximize the total biomass has the competitive advantage.


Assuntos
Alocação de Recursos , Biomassa
7.
Hum Gene Ther ; 34(23-24): 1190-1203, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37642232

RESUMO

The clustered regularly interspaced short palindromic repeat (CRISPR)-CRISPR-associated (Cas) system is a powerful genomic DNA editing tool. The increased applications of gene editing tools, including the CRISPR-Cas system, have contributed to recent advances in biological fields, such as genetic disease therapy, disease-associated gene screening and detection, and cancer therapy. However, the major limiting factor for the wide application of gene editing tools is gene editing efficiency. This review summarizes the recent advances in factors affecting the gene editing efficiency of the CRISPR-Cas9 system and the CRISPR-Cas9 system optimization strategies. The homology-directed repair efficiency-related signal pathways and the form and delivery method of the CRISPR-Cas9 system are the major factors that influence the repair efficiency of gene editing tools. Based on these influencing factors, several strategies have been developed to improve the repair efficiency of gene editing tools. This review provides novel insights for improving the repair efficiency of the CRISPR-Cas9 gene editing system, which may enable the development and improvement of gene editing tools.


Assuntos
Sistemas CRISPR-Cas , Edição de Genes , Edição de Genes/métodos , Proteína 9 Associada à CRISPR/genética , Reparo de DNA por Recombinação , Terapia Genética
8.
Dev Comp Immunol ; 142: 104667, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36773793

RESUMO

As a highly infectious pathogen, Bombyx mori nuclear polyhedrosis virus (BmNPV) has a high lethality rate in silkworm. Our previous study have confirmed that Hsp90 plays a positive role in BmNPV proliferation and Hsp90 inhibitor, geldanamycin (GA) can decrease the replication of BmNPV in vitro. However, its molecular mechanism is not fully understood. In the present study, first, we found that GA could inhibit the proliferation of BmNPV in a dose-dependent manner and delay the pathogenesis of BmNPV in vivo possibly by altering the transcript level of genes associated with cell apoptosis and immune pathways. Furthermore, by immunoprecipitation (IP) and mass spectrometry analysis, we identified a series of proteins potentially interacting with Hsp90 including two BmNPV encoded proteins. Subsequently, by Co-IP we confirmed the interaction between BmActin-4 and BmHsp90. Knocking down Bmhsp90 by small interfering RNA inhibited the protein expression level of BmActin-4. Over-expression of Bmactin-4 promoted the replication of BmNPV whereas knockdown of Bmactin-4 suppressed BmNPV replication. In addition, decrease of the transcript level of Bmhsp90 in Bmactin-4 knocking down BmN cells was also detected. Taken together, BmHsp90 can interact with BmActin-4 and promote its expression, thereby promoting BmNPV proliferation. Our findings may enrich the molecular mechanism of Hsp90 for promoting virus proliferation and provide new clues to elucidate the interact mechanism between silkworm and virus.


Assuntos
Bombyx , Nucleopoliedrovírus , Animais , Actinas/metabolismo , Nucleopoliedrovírus/genética , Proteínas de Choque Térmico HSP90/genética , Proteínas de Choque Térmico HSP90/metabolismo , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Proliferação de Células
9.
Immunotherapy ; 15(2): 101-115, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36597704

RESUMO

Gastric cancer is the fifth most common cancer worldwide. With the development of immunotherapy, especially the application of immune checkpoint inhibitors (ICIs), the prognosis of advanced gastric cancer has improved. At present, ICIs combined with other therapies or dual ICI strategies in the treatment of advanced gastric cancer have shown clinical effectiveness and controllable safety. In addition, predictive biomarkers facilitate the precise selection of patients. Therefore, it is crucial to explore rational combinations and reliable predictive biomarkers for ICI therapy. This article reviews the recent advances in ICIs and relevant predictive biomarkers in the treatment of gastric cancer.


In recent years, with the application of immunotherapy, clinical efficacy in gastric cancer has been effectively improved. At present, it is encouraging that immunotherapy combined with chemotherapy has become the first choice for the treatment of patients with advanced gastric cancer. However, researchers remain committed to exploring the efficacy of immunotherapy in combination with various therapies. Equally important, the identification of biomarkers can facilitate the selection of patients suitable for immunotherapy. This article summarizes important immunotherapy clinical trials and discusses therapeutic combinations and biomarkers being explored.


Assuntos
Inibidores de Checkpoint Imunológico , Neoplasias Gástricas , Humanos , Inibidores de Checkpoint Imunológico/uso terapêutico , Neoplasias Gástricas/terapia , Biomarcadores , Imunoterapia , Prognóstico
10.
World J Clin Cases ; 10(27): 9670-9679, 2022 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-36186212

RESUMO

BACKGROUND: Solitary fibrous tumor (SFT) is predominant within the pleura but very rare in the orbit, which is why the diagnosis of orbital SFT poses challenges in clinical practice. Accordingly, an integrated approach that incorporates specific clinical features, histological, histopathological, and immunohistochemical (IHC) examinations, and molecular analyses is warranted. AIM: To retrospectively explore the clinical and imaging characteristics, treatment, outcomes of a series of patients with orbital SFT. METHODS: We conducted a retrospective review of a series of patients diagnosed with a histopathologic orbital SFT treated at a single institution. All data on demogra/phics, clinical characteristics, imaging, treatment, postoperative histopathological and IHC examinations, and prognosis were collected. RESULTS: In total, 13 patients were enrolled, 7 (53.8%) of whom had the tumor located in the superomedial quadrant of the orbit. Computed tomography revealed a solitary ovoid lesion in 10 (76.9%) patients and irregular lesion in 3 (23.1%) patients. Magnetic resonance imaging results were as follows: On T1 weighted images, 3 (23.1%) patients had hypointense mixed signals, whereas 10 (76.9%) patients showed isointense mixed signals; on T2 weighted images (T2WI), 3 (23.1%), 4 (30.8%), and 6 (46.2%) patients exhibited hypointense mixed, isointense mixed, and hyperintense signals, respectively. Notably, 12 (92.3%) patients showed significant enhancement, whereas there were patchy slightly enhanced areas in the tumor. All patients were treated by surgery. IHC analysis demonstrated that the tumor cells were immunoreactive for CD34, CD99, STAT-6, and vimentin in all patients. The lesions showed Ki-67 positivity < 5% in 1 (7.7) patient, 5%-10% in 10 (76.9%), and > 10% in 2 (15.4%). Two (15.4%) patients exhibited tumor recurrence. CONCLUSION: The clinical manifestations and radiologic characteristics of orbital SFT are diverse and not specific. Accurate diagnosis and treatment require detailed radiological and histopathological/IHC evaluation.

11.
World J Clin Cases ; 10(5): 1623-1629, 2022 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-35211602

RESUMO

BACKGROUND: Synovial sarcoma is a malignant mesenchymal neoplasm with variable epithelial differentiation. Most synovial sarcoma cases are reported in young adults and can arise in any body site. Notably, primary orbital synovial sarcoma is rare. CASE SUMMARY: An 8-year-old east Asian girl with 1-month history of gradual painless proptosis and lacrimation of the right eye was admitted. The patient presented with painless proptosis, downward eyeball displacement, and upward movement disorders. According to clinical manifestations, imaging examinations and postoperative immunohistochemical examinations, the diagnosis was monophasic synovial sarcoma with calcification. The patient underwent anterior orbitotomy procedure for removal of the right orbital mass under general anesthesia. The diagnosis of monophasic synovial sarcoma with calcification was confirmed finally through histological and immunohistochemical exam. The follow-up period was 6 mo, and no recurrence was observed during this period. CONCLUSION: Primary orbital monophasic synovial sarcoma with calcification is a rare sarcoma, and clinical manifestations and imaging results are not specific. The tumor may present similar features as a benign tumor. Comprehensive analysis of clinical, radiological, and pathological findings is critically important for making the right diagnosis. Conventional treatment approach for synovial sarcoma is surgical resection with adjuvant or neoadjuvant radiotherapy, which is highly effective for localized tumors.

12.
Exp Ther Med ; 21(3): 253, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33603860

RESUMO

The present study aimed to explore the clinical role of heat shock protein 70 (HSP70) in patients with acute angle-closure glaucoma (AACG). Seventy-four AACG patients who were admitted to our hospital from April 2017 to April 2019 were enrolled as a study group (SG). A further 70 healthy people undergoing physical examinations during the same period were enrolled as a control group (CG). HSP70 concentration was compared between the two groups, and the clinical value of this protein in AACG was analyzed. HSP70 concentration in SG was significantly lower than that in CG (P<0.050). The sensitivity and specificity of HSP70 for diagnosing AACG were 79.73 and 74.29%, respectively (P<0.001). HSP70 concentration was positively correlated with central anterior chamber depth and peripheral anterior chamber depth, but negatively correlated with anterior angle and intraocular pressure (P<0.001). HSP70 had a relatively satisfactory predictive value for adverse reactions during the treatment (P<0.001). HSP70 concentration was markedly reduced in AACG patients, and its detection had a relatively satisfactory predictive value for AACG. Thus, HSP70 may be a potential and notable indicator for diagnosing and treating glaucoma in the future.

13.
Medicine (Baltimore) ; 100(7): e24801, 2021 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-33607842

RESUMO

RATIONALE: Orbital schwannoma is a relatively rare orbital tumor, and calcification of the lesion is rarely found in the orbit. We report a case of orbital schwannoma which was characterized by calcification in the orbital muscle cone, and was cured by intracapsular excision. PATIENT CONCERNS: A 54-year-old female with a complaint of a mass in the left orbit during a magnetic resonance imaging examination and symptom of dizziness 6 months before, presented with painless exophthalmos and vision decline in the left eye. DIAGNOSES: According to clinical manifestations, imaging examinations and postoperative immunohistochemical examinations, the diagnosis was orbital schwannoma, with calcification in the muscle cone. INTERVENTIONS: The patient was treated by intracapsular excision of the left orbit. We removed the intracapsular mass and most part of the cyst wall in order to prevent orbital apex syndrome. OUTCOMES: The diagnosis of schwannoma with calcification was confirmed finally through histological and immunohistochemical exam. The patient was followed up for 28 months and the orbital CT scan showed that there were no significant lesions found in the orbital muscle cone. LESSONS: Understanding clinical, imaging diagnostic, and histopathological features of rare orbital schwannoma with calcification will facilitate timely diagnosis and treatment of this condition. The intracapsular excision can help in avoiding complications.


Assuntos
Calcinose/cirurgia , Neurilemoma/cirurgia , Neoplasias Orbitárias/cirurgia , Calcinose/complicações , Calcinose/diagnóstico por imagem , Calcinose/patologia , Feminino , Humanos , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade , Neurilemoma/complicações , Neurilemoma/diagnóstico por imagem , Neurilemoma/patologia , Músculos Oculomotores/diagnóstico por imagem , Músculos Oculomotores/patologia , Neoplasias Orbitárias/complicações , Neoplasias Orbitárias/diagnóstico por imagem , Neoplasias Orbitárias/patologia
14.
J R Soc Interface ; 17(169): 20200429, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32752993

RESUMO

A mathematical model is developed to describe the dynamics of the spread of a waterborne disease among communities located along a flowing waterway. The model is formulated as a system of reaction-diffusion-advection partial differential equations in this spatial setting. The compartments of the model consist of susceptible, infected, and recovered individuals in the communities along the waterway, together with a term representing the pathogen load in each community and a term representing the spatial concentration of pathogens flowing along the waterway. The model is applied to the cholera outbreak in Haiti in 2010.


Assuntos
Cólera , Doenças Transmissíveis , Cólera/epidemiologia , Surtos de Doenças , Haiti/epidemiologia , Humanos , Modelos Teóricos
15.
J Math Biol ; 80(7): 2363-2393, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32415373

RESUMO

We develop a model of honey bee colony collapse based on contamination of forager bees in pesticide contaminated spatial environments. The model consists of differential and difference equations for the spatial distributions of the uncontaminated and contaminated forager bees. A key feature of the model is incorporation of the return to the hive each day of forager bees. The model quantifies colony collapse in terms of two significant properties of honey bee colonies: (1) the fraction of contaminated forager bees that fail to return home due to pesticide contamination, and (2) the fraction of forager bees in the total forager bee population that return to the sites visited on the previous day. If the fraction of contaminated foragers failing to return home is high, then the total population falls below a critical threshold and colony collapse ensues. If the fraction of all foragers that return to previous foraging sites is high, then foragers who visit contaminated sites multiple times have a higher probability of becoming contaminated, and colony collapse ensues. This quantification of colony collapse provides guidance for implementing measures for its avoidance.


Assuntos
Abelhas/efeitos dos fármacos , Colapso da Colônia/induzido quimicamente , Modelos Biológicos , Praguicidas/toxicidade , Animais , Criação de Abelhas , Abelhas/fisiologia , Colapso da Colônia/epidemiologia , Colapso da Colônia/prevenção & controle , Simulação por Computador , Poluentes Ambientais/toxicidade , Comportamento Alimentar , Comportamento de Retorno ao Território Vital , Conceitos Matemáticos
16.
J Math Biol ; 80(7): 2327-2361, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32377791

RESUMO

The dynamics of an SIS epidemic patch model with asymmetric connectivity matrix is analyzed. It is shown that the basic reproduction number [Formula: see text] is strictly decreasing with respect to the dispersal rate of the infected individuals. When [Formula: see text], the model admits a unique endemic equilibrium, and its asymptotic profiles are characterized for small dispersal rates. Specifically, the endemic equilibrium converges to a limiting disease-free equilibrium as the dispersal rate of susceptible individuals tends to zero, and the limiting disease-free equilibrium has a positive number of susceptible individuals on each low-risk patch. Furthermore, a sufficient and necessary condition is provided to characterize that the limiting disease-free equilibrium has no positive number of susceptible individuals on each high-risk patch. Our results extend earlier results for symmetric connectivity matrix, providing a positive answer to an open problem in Allen et al. (SIAM J Appl Math 67(5):1283-1309, 2007).


Assuntos
Doenças Transmissíveis/epidemiologia , Doenças Transmissíveis/transmissão , Epidemias/estatística & dados numéricos , Modelos Biológicos , Número Básico de Reprodução/estatística & dados numéricos , Simulação por Computador , Suscetibilidade a Doenças , Doenças Endêmicas/estatística & dados numéricos , Humanos , Conceitos Matemáticos
17.
Bull Math Biol ; 81(12): 4908-4931, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31515674

RESUMO

We develop a model of honey bee colony collapse based on the contamination of forager bees in environmental regions contaminated with pesticides. An important feature of the model is the daily homing capacity each day of foragers bees. The model consists of difference equations describing the daily homing of uncontaminated and contaminated forager bees, with an increased homing failure of contaminated bees. The model quantifies colony collapse in terms of the fraction of contaminated bees subject to this increased homing failure. If the fraction is sufficiently high, then the hive falls below a viability threshold population size that leads to rapid disintegration. If the fraction is sufficiently low, then the hive can rise above the viability threshold and attain a stable population level.


Assuntos
Abelhas/efeitos dos fármacos , Colapso da Colônia/induzido quimicamente , Modelos Biológicos , Praguicidas/toxicidade , Animais , Abelhas/fisiologia , Simulação por Computador , Poluentes Ambientais/toxicidade , Comportamento Alimentar/efeitos dos fármacos , Comportamento Alimentar/fisiologia , Comportamento de Retorno ao Território Vital/efeitos dos fármacos , Comportamento de Retorno ao Território Vital/fisiologia , Conceitos Matemáticos , Neonicotinoides/toxicidade
18.
Math Biosci ; 312: 77-87, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31039365

RESUMO

We investigate a time-dependent spatial vector-host epidemic model with non-coincident domains for the vector and host populations. The host population resides in small non-overlapping sub-regions, while the vector population resides throughout a much larger region. The dynamics of the populations are modeled by a reaction-diffusion-advection compartmental system of partial differential equations. The disease is transmitted through vector and host populations in criss-cross fashion. We establish global well-posedness and uniform a prior bounds as well as the long-term behavior. The model is applied to simulate the outbreak of bluetongue disease in sheep transmitted by midges infected with bluetongue virus. We show that the long-range directed movement of the midge population, due to wind-aided movement, enhances the transmission of the disease to sheep in distant sites.


Assuntos
Vírus Bluetongue/patogenicidade , Bluetongue/transmissão , Vetores de Doenças , Epidemias , Interações Hospedeiro-Patógeno , Modelos Biológicos , Análise Espaço-Temporal , Animais , Ceratopogonidae , Ovinos
19.
Math Biosci Eng ; 13(1): 1-18, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26776256

RESUMO

We consider a two-strain pathogen model described by a system of reaction-diffusion equations. We define a basic reproduction number R0 and show that when the model parameters are constant (spatially homogeneous), if R0 >1 then one strain will outcompete the other strain and drive it to extinction, but if R0 ≤ 1 then the disease-free equilibrium is globally attractive. When we assume that the diffusion rates are equal while the transmission and recovery rates are heterogeneous, then there are two possible outcomes under the condition R0 < 1: 1) Competitive exclusion where one strain dies out. 2) Coexistence between the two strains. Thus, spatial heterogeneity promotes coexistence.


Assuntos
Comportamento Competitivo/fisiologia , Extinção Biológica , Modelos Biológicos , Modelos Estatísticos , Dinâmica Populacional , Reprodução/fisiologia , Animais , Antibiose/fisiologia , Simulação por Computador , Difusão , Humanos , Simbiose/fisiologia
20.
PLoS One ; 10(3): e0119725, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25789487

RESUMO

Corneal chemical burns are common ophthalmic injuries that may result in permanent visual impairment. Although significant advances have been achieved on the treatment of such cases, the structural and functional restoration of a chemical burn-injured cornea remains challenging. The applications of polysaccharide hydrogel and subconjunctival injection of mesenchymal stem cells (MSCs) have been reported to promote the healing of corneal wounds. In this study, polysaccharide was extracted from Hardy Orchid and mesenchymal stem cells (MSCs) were derived from Sprague-Dawley rats. Supplementation of the polysaccharide significantly enhanced the migration rate of primarily cultured rat corneal epithelial cells. We examined the therapeutic effects of polysaccharide in conjunction with MSCs application on the healing of corneal alkali burns in rats. Compared with either treatment alone, the combination strategy resulted in significantly better recovery of corneal epithelium and reduction in inflammation, neovascularization and opacity of healed cornea. Polysaccharide and MSCs acted additively to increase the expression of anti-inflammatory cytokine (TGF-ß), antiangiogenic cytokine (TSP-1) and decrease those promoting inflammation (TNF-α), chemotaxis (MIP-1α and MCP-1) and angiogenesis (VEGF and MMP-2). This study provided evidence that Hardy Orchid derived polysaccharide and MSCs are safe and effective treatments for corneal alkali burns and that their benefits are additive when used in combination. We concluded that combination therapy with polysaccharide and MSCs is a promising clinical treatment for corneal alkali burns and may be applicable for other types of corneal disorder.


Assuntos
Queimaduras Químicas/terapia , Lesões da Córnea/terapia , Transplante de Células-Tronco Mesenquimais , Polissacarídeos/administração & dosagem , Álcalis/toxicidade , Animais , Queimaduras Químicas/patologia , Lesões da Córnea/patologia , Humanos , Hidrogel de Polietilenoglicol-Dimetacrilato/administração & dosagem , Células-Tronco Mesenquimais , Ratos , Cicatrização
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