102 research outputs found
Cloning of the koi herpesvirus (KHV) gene encoding thymidine kinase and its use for a highly sensitive PCR based diagnosis
BACKGROUND: Outbreaks with mass mortality among common carp Cyprinus carpio carpio and koi Cyprinus carpio koi have occurred worldwide since 1998. The herpes-like virus isolated from diseased fish is different from Herpesvirus cyprini and channel catfish virus and was accordingly designated koi herpesvirus (KHV). Diagnosis of KHV infection based on viral isolation and current PCR assays has a limited sensitivity and therefore new tools for the diagnosis of KHV infections are necessary. RESULTS: A robust and sensitive PCR assay based on a defined gene sequence of KHV was developed to improve the diagnosis of KHV infection. From a KHV genomic library, a hypothetical thymidine kinase gene (TK) was identified, subcloned and expressed as a recombinant protein. Preliminary characterization of the recombinant TK showed that it has a kinase activity using dTTP but not dCTP as a substrate. A PCR assay based on primers selected from the defined DNA sequence of the TK gene was developed and resulted in a 409 bp amplified fragment. The TK based PCR assay did not amplify the DNAs of other fish herpesviruses such as Herpesvirus cyprini (CHV) and the channel catfish virus (CCV). The TK based PCR assay was specific for the detection of KHV and was able to detect as little as 10 fentograms of KHV DNA corresponding to 30 virions. The TK based PCR was compared to previously described PCR assays and to viral culture in diseased fish and was shown to be the most sensitive method of diagnosis of KHV infection. CONCLUSION: The TK based PCR assay developed in this work was shown to be specific for the detection of KHV. The TK based PCR assay was more sensitive for the detection of KHV than previously described PCR assays; it was as sensitive as virus isolation which is the golden standard method for KHV diagnosis and was able to detect as little as 10 fentograms of KHV DNA corresponding to 30 virions
Airports at Risk: The Impact of Information Sources on Security Decisions
Security decisions in high risk organizations such as airports involve obtaining ongoing and frequent information about potential threats. Utilizing questionnaire survey data from a sample of airport
employees in European Airports across the continent, we analyzed
how both formal and informal sources of security information affect employee's decisions to comply with the security rules and
directives. This led us to trace information network flows to assess its impact on the degree employees making security decisions comply or deviate with the prescribed security rules. The results of the multivariate analysis showed that security information obtained through formal and informal networks differentially determine if employee will comply or not with the rules. Information sources emanating from the informal network tends to encourage employees to be more flexible in their security decisions
while formal sources lead to be more rigid with complying with rules and protocols. These results suggest that alongside the formal administrative structure of airports, there exists a diverse and pervasiveness set of informal communications networks that are a potent factor in determining airport security levels
Health promotion programs in prison: attendance and role in promoting physical activity and subjective health status
IntroductionMaintaining an inmate’s health can serve as a challenge due to unhealthy background, risky behavior, and long imprisonment. This study aimed to analyze the prevalence of participation in health promotion activities among Israeli inmates and its association with their physical activity levels and subjective health status.MethodsA cross-sectional study was designed to examine 522 inmates (429 males, 93 females). The data were collected by trained face-to-face interviewers and self-report questionnaires.ResultsMost of the participants (82.37%) did not meet the recommended physical activity level. Half of the participants reported that their physical activity levels decreased since they were in prison compared with 29.50% who reported that their physical activity levels increased. Physical activity and subjective health status were significantly higher among younger male inmates. Furthermore, participation in health-promoting activities was associated with higher levels of physical activity and subjective health status.DiscussionHealth promotion activities may play an important role in addressing the challenges of maintaining inmate health. Implications of the findings are further discussed
Development and validation of a multivariable risk factor questionnaire to detect oesophageal cancer in 2-week wait patients
INTRODUCTION: Oesophageal cancer is associated with poor health outcomes. Upper GI (UGI) endoscopy is the gold standard for diagnosis but is associated with patient discomfort and low yield for cancer. We used a machine learning approach to create a model which predicted oesophageal cancer based on questionnaire responses. METHODS: We used data from 2 separate prospective cross-sectional studies: the Saliva to Predict rIsk of disease using Transcriptomics and epigenetics (SPIT) study and predicting RIsk of diSease using detailed Questionnaires (RISQ) study. We recruited patients from National Health Service (NHS) suspected cancer pathways as well as patients with known cancer. We identified patient characteristics and questionnaire responses which were most associated with the development of oesophageal cancer. Using the SPIT dataset, we trained seven different machine learning models, selecting the best area under the receiver operator curve (AUC) to create our final model. We further applied a cost function to maximise cancer detection. We then independently validated the model using the RISQ dataset. RESULTS: 807 patients were included in model training and testing, split in a 70:30 ratio. 294 patients were included in model validation. The best model during training was regularised logistic regression using 17 features (median AUC: 0.81, interquartile range (IQR): 0.69-0.85). For testing and validation datasets, the model achieved an AUC of 0.71 (95% CI: 0.61-0.81) and 0.92 (95% CI: 0.88-0.96) respectively. At a set cut off, our model achieved a sensitivity of 97.6% and specificity of 59.1%. We additionally piloted the model in 12 patients with gastric cancer; 9/12 (75%) of patients were correctly classified. CONCLUSIONS: We have developed and validated a risk stratification tool using a questionnaire approach. This could aid prioritising patients at high risk of having oesophageal cancer for endoscopy. Our tool could help address endoscopic backlogs caused by the COVID-19 pandemic
Three low-mass companions around aged stars discovered by TESS
We report the discovery of three transiting low-mass companions to aged
stars: a brown dwarf (TOI-2336b) and two objects near the hydrogen burning mass
limit (TOI-1608b and TOI-2521b). These three systems were first identified
using data from the Transiting Exoplanet Survey Satellite (TESS). TOI-2336b has
a radius of , a mass of and an orbital
period of 7.71 days. TOI-1608b has a radius of , a mass of
and an orbital period of 2.47 days. TOI-2521b has a radius
of , a mass of and an orbital period of
5.56 days. We found all these low-mass companions are inflated. We fitted a
relation between radius, mass and incident flux using the sample of known
transiting brown dwarfs and low-mass M dwarfs. We found a positive correlation
between the flux and the radius for brown dwarfs and for low-mass stars that is
weaker than the correlation observed for giant planets.Comment: 20 pages, 13 figures; submitted to MNRA
A massive hot Jupiter orbiting a metal-rich early-M star discovered in the TESS full frame images
Observations and statistical studies have shown that giant planets are rare
around M dwarfs compared with Sun-like stars. The formation mechanism of these
extreme systems remains under debate for decades. With the help of the TESS
mission and ground based follow-up observations, we report the discovery of
TOI-4201b, the most massive and densest hot Jupiter around an M dwarf known so
far with a radius of and a mass of ,
about 5 times heavier than most other giant planets around M dwarfs. It also
has the highest planet-to-star mass ratio () among such
systems. The host star is an early-M dwarf with a mass of $0.61\pm0.02\
M_{\odot}0.63\pm0.02\ R_{\odot}0.52\pm 0.08$ dex). However, interior
structure modeling suggests that its planet TOI-4201b is metal-poor, which
challenges the classical core-accretion correlation of stellar-planet
metallicity, unless the planet is inflated by additional energy sources.
Building on the detection of this planet, we compare the stellar metallicity
distribution of four planetary groups: hot/warm Jupiters around G/M dwarfs. We
find that hot/warm Jupiters show a similar metallicity dependence around G-type
stars. For M dwarf host stars, the occurrence of hot Jupiters shows a much
stronger correlation with iron abundance, while warm Jupiters display a weaker
preference, indicating possible different formation histories.Comment: 21 pages, 11 figures, 4 tables, submitted to A
TESS delivers its first Earth-sized planet and a warm sub-Neptune
The future of exoplanet science is bright, as TESS once again demonstrates
with the discovery of its longest-period confirmed planet to date. We hereby
present HD 21749b (TOI 186.01), a sub-Neptune in a 36-day orbit around a bright
(V = 8.1) nearby (16 pc) K4.5 dwarf. TESS measures HD21749b to be
2.61 , and combined archival and follow-up
precision radial velocity data put the mass of the planet at
. HD 21749b contributes to the TESS Level 1
Science Requirement of providing 50 transiting planets smaller than 4
with measured masses. Furthermore, we report the discovery of HD
21749c (TOI 186.02), the first Earth-sized () planet from TESS. The HD21749 system is a prime target for
comparative studies of planetary composition and architecture in multi-planet
systems.Comment: Published in ApJ Letters; 5 figures, 1 tabl
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