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1.
Spectrochim Acta A Mol Biomol Spectrosc ; 320: 124438, 2024 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-38901237

RESUMO

Barium lead alumino fluoroborate (BaPbAlFB) glasses singly and co-doped with Dy3+ and Eu3+ ions were prepared by melt quench method and studied their photoluminescence (PL) properties along with energy migration. Singly doped Dy3+/Eu3+ ions in BaPbAlFB glasses under 365 and 393 nm excitation wavelengths emit the PL bands through Dy: (4F9/2 → 6H15/2 and 4F9/2 → 6H13/2) and Eu: (5D0→7F2) transitions located at (Dy: 483 and 575 nm) and (Eu: 613 nm) respectively. Further, tunability of PL emissions is achieved by exciting the Dy3+/Eu3+ co-doped BaPbAlFB glasses at various wavelengths. The obtained CIE (0.34, 0.33) and CCT value (5080.4 K) of Dy3+/Eu3+ co-doped BaPbAlFB glass produced white light emission under 365 nm excitation wavelength. The corresponding CCT values of Dy3+/Eu3+ co-doped BaPbAlFB glasses varied from 1580 to 5080 K and their corresponding color emission changes from intense red to white light regime quite suitable for fabrication of epoxy-free w-LED devices.

2.
J Fluoresc ; 2023 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-38157084

RESUMO

Dysprosium oxide-doped glasses with a composition of 60B2O3-10Sb2O3-10Al2O3-10NaF-(10-x) LiF-xDy2O3 (x = 0.1,0.5, 1.0,1.5,2.0,2.5 mol%) were prepared using a conventional melt-quenching technique. The glasses were characterized through various analytical investigations, including X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, refractive index, density, optical absorption, excitation, photoluminescence (PL) studies, decay measurements and radiation shielding parameters. The XRD and FT-IR confirms the glassy nature and functional groups present in the titled glass. The absorption spectra were used to determine the oscillator strength of the Dy3+ absorption transitions as well as the bond created with the O-2 ion in the titled glass network. The degree of the suitability of developed glasses for lasing applications was demonstrated by radiative parameters determined using Judd-Ofelt theory. In the prepared glass samples, the optical bandgap measurements indicate the presence of non-bridging oxygen (NBOs), localization of charges and donor centers in the titled glasses. Due to the de-excitation of 4F9/2 to the corresponding 6H15/2,6H13/2 and 6H11/2 states, the PL emission spectrum shows two main strong emissions at blue(480nm), yellow (575nm) and one less emission at red (663nm). The CIE coordinates determined using PL emission spectra reveal the coordinates that are falling within the white light region. Various shielding parameters such as mass attenuation coefficient, mean free path, effective atomic number were estimated to understand the radiative shielding nature of the titled glasses. Within the addition of Dy2O3, it was found that the shielding parameters values of the titled glass samples are increasing. The Mass Attenuation Coefficient, Half Value Layer and Mean Free Path of the as prepared glasses has been compared with different types of concretes to understand the shielding effectiveness of prepared glass.

3.
RSC Adv ; 13(48): 33675-33687, 2023 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-38020000

RESUMO

This paper investigates the synthesis and luminescence characteristics of Tm3+/Tb3+/Eu3+ co-doped Sr4Nb2O9 (SNB) phosphors as potential candidates for white light-emitting diodes (WLEDs). The study explores the energy transfer mechanisms and color-tunable characteristics of these phosphors. The SNB phosphors were prepared using a solid-state reaction method, and their structural and morphological properties were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Fourier-transform infrared (FT-IR) spectroscopy. The diffuse reflectance, photoluminescence (PL) and time resolved photoluminescence (TRPL) properties were investigated, revealing efficient energy transfer processes from Tm3+ to Tb3+ and Eu3+ ions. The energy transfer mechanisms were determined through critical distance calculations and analysis of multipolar interactions. The co-doped phosphors exhibited tunable emission colors ranging from blue to white light, with controllable correlated color temperatures (CCTs) and high color rendering indices (CRIs). The CIE chromaticity coordinates were optimized to approach neutral white light. The PL intensity is maintained at 81.19% at 150 °C of that of room temperature which showcases the remarkable thermal stability of the as-prepared phosphors. The results highlight the potential of Tm3+/Tb3+/Eu3+ co-doped SNB phosphors for generating high-quality, color-tunable white light for advanced lighting applications.

4.
J Fluoresc ; 2023 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-37804477

RESUMO

In the current study, Sm3+ ions doped Lithium Barium Tungstate (Li2Ba5W3O15) (LBW) phosphors with the ability to emit orange-red light were made using the traditional high-temperature solid-state reaction technique. The structure and phase of the as-synthesized phosphor samples were examined via X-ray diffraction (XRD) patterns. The diffraction peaks of the undoped LBW and Sm3+ ions doped LBW phosphors closely resemble those of the Joint Committee on Powder Diffraction Standards (JCPDS) pattern with card number 01-072-1717. Scanning electron microscopy (SEM) was employed for the analysis of the morphological characteristics of the synthesized phosphor material. Fourier Transform Infrared (FT-IR) spectroscopy was used to study several vibrational and molecular bands present in the host matrix. Using diffuse reflectance spectra (DRS), the optical band gap values (Eg) were evaluated by applying Tauc's method. The photoluminescence (PL) spectra characteristics at λex = 336 nm indicate the emission of dopant ions (Sm3+) in the deep orange-red region corresponding to 4G5/2 → 6H5/2 transition (at 581 nm) with concentration quenching after 2 mol % of Sm3+ ions. Using the PL spectra, the CIE chromaticity coordinates of LBWS2.0 phosphor were estimated and found in the deep visible orange-red area, indicating the potential use of the prepared phosphor material for phosphor-converted white light emitting diodes (w-LEDs) applications. Double exponential behaviour can be seen in the PL decay spectral profiles obtained under λem = 581 nm and λex = 336 nm. The experimental lifetimes (τexp) decrease as the concentration of Sm3+ ions rise. The temperature-dependent PL (TDPL) and activation energy results show that the as-synthesized phosphor has considerably superior thermal stability. The results of the current research contemplate us the applicability of Sm3+ ions doped LBW phosphor for photonic devices such as w-LEDs.

5.
RSC Adv ; 13(24): 16663-16670, 2023 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-37274394

RESUMO

Chromium-doped calcium aluminozincate phosphor with a distinct amount of chromium was prepared via the sol-gel technique. The phase analysis and morphological study along with optical properties were conducted on the prepared material. The room temperature luminescent traits of the sample were studied in detail under 540 nm excitation wavelength. The deep red emission was confirmed from the CIE coordinates calculated using emission data. The decay curves were recorded to calculate the lifetime values for the aforementioned powder samples. The temperature-dependent luminescent characteristics were also investigated to identify the activation energy and thermal stability. The quantum yield was also calculated using luminescence spectra and found to be relatively good for the present phosphor. All of the investigated studies specified above signify that the synthesized phosphor is well suited as a red emitter in lighting and display devices.

6.
RSC Adv ; 13(17): 11557-11568, 2023 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-37063722

RESUMO

With an intend to develop white light emitting phosphor, for w-LED application, a series of dysprosium (Dy3+) doped novel Na3Ba2LaNb10O30 phosphors were prepared using solid state reaction technique at 1300 °C. Their structural, morphological and vibrational spectroscopic analysis was performed. We illustrate the luminescence characteristics of the prepared phosphors for various Dy3+ ion doping concentration. The XRD analysis demonstrates that the prepared phosphors were in single phase, and of tetragonal tungsten bronze structure of the P4bm space group. The FE-SEM image reveals that the prepared phosphors contained irregular shaped both nano and micro particles. Under near-ultraviolet (n-UV) irradiation at 387 nm, the photoluminescence (PL) emission spectra shows three characteristic bands at 481 nm (blue), 575 nm (yellow) and 666 nm (red). Obtained optimized Dy3+ ion concentration for the prepared sample is 7.0 mol%, beyond which the concentration quenching begins. Bonding between Dy-O is covalent in nature as confirmed by bonding parameters and the Dexter theory revealed that the energy transfer among Dy3+ ions is dipole-diploe interaction. CIE chromaticity coordinates, CCT and color purity confirms the formation of warm white light emitting phosphors. Lifetime analysis demonstrates the longer decay time in the phosphors. The Internal Quantum Yield (IQE) and brightness (B) for the optimised phosphor is calculated as 45.35% and 11.41% respectively, which makes it a suitable phosphor for w-LED.

7.
Environ Res ; 206: 112575, 2022 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-34932979

RESUMO

While Indigenous food systems remain critical for community well-being, traditionally harvested foods are a potential source of toxic exposures. The Tsleil-Waututh Nation (TWN) is seeking to restore shellfish harvesting in Burrard Inlet (British Columbia [BC], Canada), where the cumulative effects of industrial activity have nearly eliminated safe harvesting. The Trans Mountain Expansion project would triple the capacity to transport oil through the inlet, threatening TWN's progress to restore shellfish harvesting. To inform ongoing efforts we assessed contamination by heavy metals (arsenic, cadmium, lead, and mercury) and 48 polycyclic aromatic hydrocarbons (PAHs) congeners in different shellfish species (Softshell clams, Varnish clams, and Dungeness crab) in three areas. We compared our results against local screening values (SVs) established by the TWN and BC Ministry of Environment and Climate Change Strategy, as well as provincial and national benchmarks. In total, we analyzed 18 composite samples of Softshell clams and Varnish clams (5 individuals per sample), as well as 17 individual crabs. We found chemical contamination in all species at all sites. PAHs were most frequently detected in Softshell clams, highest in the site closest to the pipeline terminus. Clams presented higher levels of contamination than crabs for PAHs, but not for heavy metals. For Softshell and Varnish clams, all heavy metals across study sites exceeded at least one of the population-specific SVs. Of the 14 PAHs detected, benzo(a)pyrene presented a median concentration in Softshell clams of 3.25 µ/kg, exceeding local SV for subsistence fisher. Our results call for further assessment of human health impacts related to food harvesting within Burrard Inlet and establishing a long-term coordinated program co-led by the TWN to monitor contamination and inform future harvesting programs. The study draws attention to the need to consider locally-relevant toxicity benchmarks, and include potential health impacts of food contamination in appraising development project proposals.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos , Poluentes Químicos da Água , Baías , Colúmbia Britânica , Monitoramento Ambiental , Contaminação de Alimentos/análise , Inocuidade dos Alimentos , Humanos , Desenvolvimento Industrial , Hidrocarbonetos Policíclicos Aromáticos/análise , Frutos do Mar/análise , Poluentes Químicos da Água/análise
8.
Spine Deform ; 9(4): 949-954, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33660241

RESUMO

INTRODUCTION: Clinicians and patients must weigh the benefits of radiological imaging against the risks of radiation exposure in the diagnosis and treatment of scoliosis. This report aims to estimate the cumulative absorbed and equivalent dose of radiation in patients undergoing surgical treatment for scoliosis, and to present this as an estimated risk of cancer compared to background radiation levels. METHODS: Retrospective review of estimated absorbed dose on the Computerised Radiology Information System (CRIS®). Patients undergoing surgical correction of scoliosis (age ≤ 25) from August 2010 to August 2015 investigated. Estimated absorbed dose [milligrays (mGy)] recorded. Pedicle screws inserted using image intensification. Equivalent dose [millisieverts (mSv)] and additional cancer risk calculated from the National Research Council document 'Health risks from exposure to low levels of ionising radiation' (2006). RESULTS: 271 patients identified. Mean age 15 (range 2-25). Mean total absorbed dose 2136 mGy [standard deviation (SD) 1700 mGy]. Mean number of plain spine radiographs was 8 (SD 3) with total 1884 mGy exposure (SD 1609 mGy). Additional dose provided by CT (mean 0.17 episodes), plain chest and abdominal radiographs and image intensification. Mean number of image intensification episodes was 1.1 with mean estimated exposure 180 mGy (SD 238 mGy). Image intensification accounted for 8% of the estimated absorbed dose during treatment. Estimated mean effective dose delivered was 20.952 mSv equating to an additional cancer risk of 0.27-0.45%. CONCLUSION: Additional cancer risk from cumulative imaging is small and equivalent to approximately 8 years of natural background radiation. Use of image intensification for pedicle screw insertion is a minor contribution (8%) to the total patient dose.


Assuntos
Neoplasias , Escoliose , Adolescente , Criança , Humanos , Doses de Radiação , Estudos Retrospectivos , Escoliose/diagnóstico por imagem , Escoliose/cirurgia , Tomografia Computadorizada por Raios X , Raios X
10.
J Appl Microbiol ; 131(5): 2114-2130, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33570824

RESUMO

The essence of appropriate nutritional intake on a regular basis has a great impact in maintaining fundamental physiological functions and the body metabolism. Considering how pivotal maintaining a nourishing fat diet is to human health, Omega-3 fatty acids have gained a lot of attention in recent times. Omega-3 fatty acids (n-3 FAs) such as eicosapentaenoic acid (EPA) and DHA are considered as essential fatty acids (EFAs) offering enormous nutritional benefits: from playing a major role in the prevention and treatment of a number of human diseases, such as cardiovascular disorders and neurological disorders, to having anti-inflammatory properties, to providing joint support, etc. Hence, their incorporation into our daily diet is of great importance. Also, both EPA and DHA have been shown to be therapeutically significant in treating several infectious diseases. EFAs were initially thought to be marine in origin, produced by fishes. Consequentially, this led to the increase in the industrial extraction of fish oils for meeting the commercial need for of n-3-rich dietary supplements. Although fish oil supplementation met almost all of the dietary demand for EFAs, they did come with a fair share of drawbacks such as undesirable odour and flavour, heavy metal contamination, extinction of fish species, etc. Oleaginous micro-organisms are a promising alternative for the production of a more sustainable, consistent and quality production of n-3 FAs. Thus, the entire review focuses on understanding the eco-friendlier production of n-3 FAs by micro-organisms.


Assuntos
Ácidos Docosa-Hexaenoicos , Ácidos Graxos Ômega-3 , Dieta , Suplementos Nutricionais , Ácido Eicosapentaenoico , Óleos de Peixe , Humanos
11.
Dalton Trans ; 49(29): 10058-10068, 2020 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-32657304

RESUMO

Systematic and strong rare-earth photoluminescence (PL) color flips that are highly sensitive to structural phase transformation in KLaF4:RE3+ (RE3+ = Eu3+, Er3+/Yb3+) nanocrystals are demonstrated. Room-temperature wet chemical synthesis at various reaction times involves a systematic conversion from cubic (α, space group Fm3[combining macron]m) to hexagonal (ß, space group P6[combining macron]2m) polymorph nanocrystals of 4 to 8 nm sizes. The unusual down-conversion photoluminescence (DC-PL) asymmetric ratio of the hypersensitive transition (5D0→7F2, Red) to that of nearly invariant transition (5D0→7F1, Orange) (R/O from 1.2 to 3.0) of KLaF4:Eu3+ is substantially affected by the site-selective occupancy and local symmetry around the Eu3+ ions, according to crystal packing transformation. The NIR excited up-conversion photoluminescence (UC-PL) of Er3+ ions produces a strong color flip from green (2H11/2 and 4S3/2) to red (4F9/2) dominated emissions based on their cubic or hexagonal crystal packing. The site occupancy and phonon energies strongly influence various nonlinear energy transfer mechanisms within RE3+ ion energies and the results are explained accordingly. The present study substantially reveals the local host effects and these two distinct polymorph nanoparticles can be potentially utilized for color-specific studies related to applications such as color-specific biological in vitro and in vivo imaging and other optoelectronic device applications.

12.
Spectrochim Acta A Mol Biomol Spectrosc ; 240: 118568, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32554261

RESUMO

The ZnO + Bi2O3 + BaF2 + B2O3 + TeO2 (ZnBiBaBFTe) host glass was prepared by melt quenching technique with the aim of achieving white light emission from Dy3+ ions. Their structural and spectroscopic properties were systemically investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV-Visible absorption, emission spectra and decay times. Judd-Ofelt (JO) parameters (Ωλ) evaluated from absorption spectrum were utilized to calculate the radiative parameters for 4F9/2 level of Dy3+ ions. The optical band gap energy of as-prepared glasses were calculated for the indirect, (αhυ)1/2 and direct, (αhυ)2 allowed transitions. The emission spectra of Dy3+:ZnBiBaBFTe glasses showed two intense peaks at 575 nm (4F9/2→6H13/2) and 481 nm (4F9/26H15/2) upon 386 nm excitation. The highest emission intensity was observed at 1.0 mol% of Dy3+ for 4F9/2→6H13/2 transition and the results are used in conjunction with lifetime measurements to derive spectroscopic parameters for the stimulated emission cross-section (25.2 × 10-22 cm2), gain bandwidth (5.86 × 10-28 cm3), and favourable quantum efficiency (74.2%). Moreover, white light can be realized with a CIE coordinates by adjusting the concentration of Dy3+ ions in ZnBiBaBFTe host glass. Efficient spectroscopic values and realizable white lighting in Dy3+-doped ZnBiBaBFTe glasses may have potential applications in laser illumination devices.

13.
Phytother Res ; 34(8): 1902-1925, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32147928

RESUMO

Tephrosia purpurea (L.) Pers. is a well-known plant in Ayurveda and named "Sarwa wranvishapaka" for its property to heal wounds. Traditionally, it is practiced for impotency, asthma, dyspepsia, hemorrhoids, syphilis gonorrhea, rheumatism, enlargement of kidney and spleen. It is an important component of herbal preparations like Tephroli and Yakrifti used to cure liver disorders. Various phytocompounds including pongamol, purpurin, purpurenone, tephrosin, bulnesol, tephrostachin, ß-sitosterol, and so on have been reported. Modern pharmacological studies have shown that the plant have wound healing, antileishmanial, anticarcinogenic, antimicrobial, antioxidant, hepatoprotective, antifertility, antispermatogenic, anti-diarrheal, diuretic, and insecticidal properties. Acetylcholinesterase inhibitory action reported from this plant aids its utilization for the development of drugs for Alzheimer's and dementia neurological disorders. Among the known active compounds of T. purpurea, tephrostachin is responsible for antiplasmodial activity, tephrosin, pongaglabol, and semiglabrin exerts antiulcer activity while quercetin, rutin, ß-sitosterol, and lupeol are mainly responsible for its anti-inflammatory and anti-cancer properties. From different toxicological studies, concentrations up to 2,000 mg/kg were considered safe. The present review comprehensively summarizes the ethnomedicine, phytochemistry, pharmacology, and toxicology of T. purpurea. Further research on elucidation of the structure-function relationship among active compounds, understanding of multi-target network pharmacology and clinical applications will intensify its therapeutic potential.


Assuntos
Ayurveda/métodos , Medicina Tradicional/métodos , Plantas/química , Tephrosia/toxicidade , Humanos
14.
Heliyon ; 6(2): e03260, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32055725

RESUMO

Qualitative elemental analysis was determined in various parts of potential anti-asthmatic medicinal plants using Energy Dispersive X-ray Fluorescence (EDXRF) spectrometer. X-ray beam was used to excite each sample and spectra were recorded with a high resolution Si(Li) detector. The data analysis was carried out by the nEXT software. Trace elements P, S, Cl, K, Ca, Mn, Fe, Cu, Zn, Se, Br, Rb and Sr were estimated and elemental concentrations were determined. The results of the present study compared with standard reference material NIST1515 apple leaves for accuracy. The elements K, Ca, Cl, S and P are major constituents and besides Cu, Zn, Fe, Mn, Se, Br, Rb and Sr were present at low level. The presence of Cu, Zn, Mn and Se in medicinal plants plays a vital role on management and control of asthma disease.

15.
Endosc Ultrasound ; 8(6): 418-427, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31552915

RESUMO

BACKGROUND AND OBJECTIVES: Currently, pancreatic cystic lesions (PCLs) are recognized with increasing frequency and have become a more common finding in clinical practice. EUS is challenging in the diagnosis of PCLs and evidence-based decisions are lacking in its application. This study aimed to develop strong recommendations for the use of EUS in the diagnosis of PCLs, based on the experience of experts in the field. METHODS: A survey regarding the practice of EUS in the evaluation of PCLs was drafted by the committee member of the International Society of EUS Task Force (ISEUS-TF). It was disseminated to experts of EUS who were also members of the ISEUS-TF. In some cases, percentage agreement with some statements was calculated; in others, the options with the greatest numbers of responses were summarized. RESULTS: Fifteen questions were extracted and disseminated among 60 experts for the survey. Fifty-three experts completed the survey within the specified time frame. The average volume of EUS cases at the experts' institutions is 988.5 cases per year. CONCLUSION: Despite the limitations of EUS alone in the morphologic diagnosis of PCLs, the results of the survey indicate that EUS-guided fine-needle aspiration is widely expected to become a more valuable method.

16.
J Appl Microbiol ; 127(3): 683-692, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31216600

RESUMO

AIMS: The objective of this study was to compare qualitatively and quantitatively the results of identification of the bacteria present in milk samples from cows with subclinical mastitis using multiplex qPCR assay and matrix-assisted laser desorption-ionization time of flight mass spectrometry (MALDI-TOF MS® ) after bacteriological growth. METHODS AND RESULTS: A total of 182 samples were aseptically collected from 119 cows with high somatic cell counts (>2·105 SCC per ml) on 11 farms in Belgium in 2014. The mutiplex qPCR assay was carried out on 350 µl of milk with the PathoProof® Complete-16kit. Ten microlitre of milk was streaked on Columbia blood agar and three selective agar plates. Growing colonies were identified by MALDI-TOF MS. Of the 182 samples, 90 gave positive results with either or both tests for one or two bacterial species/genera. Total qualitative agreement of the bacteria identified was observed in 41 mono- or bi-bacterial samples (46%) and partial agreement in 19 bi-bacterial samples at both or either tests (21%). The results of both tests on those mono- and bi-bacterial samples were not significantly different (McNemar test; P = 0·395) with a fair agreement (Cohen's kappa test; k = 0·375; P = 0·055). Moreover, quantitative correlation between the qPCR intensity and the numbers of growing colonies was observed in half of the 60 samples with qualitative matching results. CONCLUSIONS: Both methods give identical qualitative and quantitative results with approximately a half and a quarter of the mono- and bi-bacterial samples respectively. Several reasons can explain the differences. The multiplex qPCR assay only targets the most important mammary gland pathogens and can detect DNA of bacteria both alive and dead. Conversely, bacteria only grow when alive and the MALDI-TOF MS databases do not include all bovine milk-associated bacterial species yet. SIGNIFICANCE AND IMPACT OF THE STUDY: This study further highlights the limitations and complementarity of the genetic and phenotypic tests for the identification of bacteria present in milk samples.


Assuntos
Bactérias/isolamento & purificação , Mastite Bovina/microbiologia , Leite/microbiologia , Reação em Cadeia da Polimerase em Tempo Real , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Animais , Bactérias/genética , Bovinos , Feminino
18.
Vet Parasitol ; 233: 62-72, 2017 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-28043390

RESUMO

Coccidiosis is one of the biggest challenges faced by the global poultry industry. Recent studies have highlighted the ubiquitous distribution of all Eimeria species which can cause this disease in chickens, but intriguingly revealed a regional divide in genetic diversity and population structure for at least one species, Eimeria tenella. The drivers associated with such distinct geographic variation are unclear, but may impact on the occurrence and extent of resistance to anticoccidial drugs and future subunit vaccines. India is one of the largest poultry producers in the world and includes a transition between E. tenella populations defined by high and low genetic diversity. The aim of this study was to identify risk factors associated with the prevalence of Eimeria species defined by high and low pathogenicity in northern and southern states of India, and seek to understand factors which vary between the regions as possible drivers for differential genetic variation. Faecal samples and data relating to farm characteristics and management were collected from 107 farms from northern India and 133 farms from southern India. Faecal samples were analysed using microscopy and PCR to identify Eimeria occurrence. Multiple correspondence analysis was applied to transform correlated putative risk factors into a smaller number of synthetic uncorrelated factors. Hierarchical cluster analysis was used to identify poultry farm typologies, revealing three distinct clusters in the studied regions. The association between clusters and presence of Eimeria species was assessed by logistic regression. The study found that large-scale broiler farms in the north were at greatest risk of harbouring any Eimeria species and a larger proportion of such farms were positive for E. necatrix, the most pathogenic species. Comparison revealed a more even distribution for E. tenella across production systems in south India, but with a lower overall occurrence. Such a polarised region- and system-specific distribution may contribute to the different levels of genetic diversity observed previously in India and may influence parasite population structure across much of Asia and Africa. The findings of the study can be used to prioritise target farms to launch and optimise appropriate anticoccidial strategies for long-term control.


Assuntos
Coccidiose/veterinária , Eimeria/fisiologia , Variação Genética , Doenças das Aves Domésticas/epidemiologia , Doenças das Aves Domésticas/parasitologia , Criação de Animais Domésticos , Animais , Biodiversidade , Galinhas , Análise por Conglomerados , Coccidiose/epidemiologia , Coccidiose/parasitologia , DNA de Protozoário/genética , Eimeria/genética , Fezes/parasitologia , Geografia , Índia/epidemiologia , Prevalência , Fatores de Risco
20.
J Dairy Sci ; 99(3): 2026-2042, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26778316

RESUMO

A blinded, negative controlled, randomized intervention study was undertaken to test the hypothesis that addition of meloxicam, a nonsteroidal anti-inflammatory drug, to antimicrobial treatment of mild to moderate clinical mastitis would improve fertility and reduce the risk of removal from the herd. Cows (n=509) from 61 herds in 8 regions (sites) in 6 European countries were enrolled. Following herd-owner diagnosis of mild to moderate clinical mastitis within the first 120 d of lactation in a single gland, the rectal temperature, milk appearance, and California Mastitis Test score were assessed. Cows were randomly assigned within each site to be treated either with meloxicam or a placebo (control). All cows were additionally treated with 1 to 4 intramammary infusions of cephalexin and kanamycin at 24-h intervals. Prior to treatment and at 14 and 21 d posttreatment, milk samples were collected for bacteriology and somatic cell count. Cows were bred by artificial insemination and pregnancy status was subsequently defined. General estimating equations were used to determine the effect of treatment (meloxicam versus control) on bacteriological cure, somatic cell count, the probability of being inseminated by 21 d after the voluntary waiting period, the probability of conception to first artificial insemination, the number of artificial insemination/conception, the probability of pregnancy by 120 or 200 d postcalving, and the risk of removal by 300 d after treatment. Cox's proportional hazards models were used to test the effect of treatment on the calving to first insemination and calving to conception intervals. Groups did not differ in terms of age, clot score, California Mastitis Test score, rectal temperature, number of antimicrobial treatments given or bacteria present at the time of enrollment, but cows treated with meloxicam had greater days in milk at enrollment. Cows treated with meloxicam had a higher bacteriological cure proportion than those treated with the placebo [0.66 (standard error=0.04) versus 0.50 (standard error=0.06), respectively], although the proportion of glands from which no bacteria were isolated posttreatment did not differ between groups. No difference was observed in the somatic cell count between groups pre- or posttreatment. The proportion of cows that underwent artificial insemination by 21 d after the voluntary waiting period was unaffected by treatment. Treatment with meloxicam was associated with a higher proportion of cows conceiving to their first artificial insemination (0.31 versus 0.21), and a higher proportion of meloxicam-treated cows were pregnant by 120 d after calving (0.40 versus 0.31). The number of artificial inseminations required to achieve conception was lower in the meloxicam compared with control cows (2.43 versus 2.92). No difference was observed between groups in the proportion of cows pregnant by 200 d after calving or in the proportion of cows that were culled, died, or sold by 300 d after calving (17% versus 21% for meloxicam versus control, respectively). It was concluded that use of meloxicam, in conjunction with antimicrobial therapy, for mild to moderate cases of clinical mastitis, resulted in a higher probability of bacteriological cure, an increased probability of conception to first artificial insemination, fewer artificial inseminations, and a greater proportion of cows pregnant by 120 d in milk.


Assuntos
Anti-Inflamatórios não Esteroides/uso terapêutico , Mastite Bovina/tratamento farmacológico , Reprodução/efeitos dos fármacos , Tiazinas/uso terapêutico , Tiazóis/uso terapêutico , Animais , Antibacterianos/uso terapêutico , Bactérias , Bovinos , Contagem de Células , Cefalexina/uso terapêutico , Quimioterapia Combinada , Europa (Continente)/epidemiologia , Feminino , Fertilidade , Fertilização , Inseminação Artificial/veterinária , Canamicina/uso terapêutico , Lactação/efeitos dos fármacos , Mastite/tratamento farmacológico , Mastite Bovina/epidemiologia , Meloxicam , Leite/microbiologia , Gravidez
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