Minimum Detection Threshold Research Articles

Establishment of a Raman nanosphere based immunochromatographic system for the combined detection of influenza A and B viruses’ antigens on a single T-line

A simple and rapid system based on Raman nanosphere (R-Sphere) immunochromatography was developed in this study for the simultaneous detection of Influenza A, B virus antigens on a single test line (T-line). Two types of R-Sphere with different characteristic Raman spectrum were used as the signal source, which were labeled with monoclonal antibodies against FluA, FluB (tracer antibodies), respectively. A mixture of antibodies containing anti-FluA monoclonal antibody and anti-FluB monoclonal antibody (capture antibody) was sprayed on a single T-line and goat anti-chicken IgY antibody was coated as a C-line, and the antigen solution with known concentration was detected by the strip of lateral flow immunochromatography based on surface-enhanced Raman spectroscopy (SERS). The T-line was scanned with a Raman spectrometer and SERS signals were collected. Simultaneous specific recognition and detection of FluA and FluB were achieved on a single T-line by analyzing the SERS signals. The findings indicated that the test system could identify FluA and FluB in a qualitative manner in just 15 minutes, with a minimum detection threshold of 0.25 ng ml-1, excellent consistency, and specificity. There was no interference with the other four respiratory pathogens, and it exhibited 8 times greater sensitivity compared to the colloidal gold test strip method. The assay system is rapid, sensitive, and does not require repetitive sample pretreatment steps and two viruses can be detected simultaneously on a single T-line by titrating one sample, which improves detection efficiency, and provide a reference for developing multiplexed detection techniques for other respiratory viruses.

Research Note: Development of a reverse transcriptase recombinase-aided amplification method for detection of Parrot Borna Virus 4

The Parrot Borna virus 4 (PaBV-4) is the primary causative agent of parrot developmental disorder (PDD), leading to symptoms such as bloating, undigested feed in stool, decreased appetite, diarrhea, and weight loss. Its impact on the parrot industry has been significant, therefore, it is imperative to develop a rapid detection method for PaBV-4. The detection of PaBV-4 was achieved through the development of an RT-RAA assay, which involved the design of specific probes and primers targeting the N gene. This method allows for detection at 41°C within 30 min and has a minimum detection threshold of 8.56 × 101 copies/μL. The RT-RAA method demonstrated specific detection of PaBV-4 without any cross-reactivity observed with H5N6, H7N9, H9N2 avian influenza virus, newcastle disease virus (NDV), avian infectious bronchitis virus (IBV) and Parrot Borna virus 2 (PaBV-2). The coefficient of variation for the 3 repeatability experiments was below 10%. Tissue samples from 28 suspected cases of PaBV related deaths in parrots were analyzed using both RT-RAA and RT-qPCR methods. The sensitivity and specificity of both methods were 100%, demonstrating perfect agreement between them as indicated by a kappa value of 1. In conclusion, this study created a RT-RAA method for PaBV-4 detection successfully.

A photoelectrochemical sensor based on In2S3/AgInS2 in situ Z-type heterojunction with “photo-modulated interface charge” for sensitive detection of Programmed Death-Ligand 1

The construction of heterostructure photoelectrodes can enhance the performance of photoelectrochemical (PEC) sensors. However, it is still a critical challenge to achieve efficient transfer of interface carriers. In this paper, we propose a strategy of “photo-modulated interface charge” to design a PEC sensor based on a hollow hexagonal tubular In2S3/AgInS2 in situ Z-type heterojunction for the susceptible detection of Programmed Death-ligand 1 (PD-L1). The hollow structured In2S3/AgInS2 is ingeniously synthesized employing indium-sourced MIL-68 as a sacrificial template and in situ cation exchange technique. This composite material has close contact interfaces due to in situ growth, which facilitates the spontaneous establishment of a robust and stable built-in electric field between the interfaces. Moreover, the inner cavity structure promotes multiple light refractions and scatterings, significantly enhancing light trapping capability. Under the influence of both light irradiation and electric field force, the migration direction of the interfacial charge is reversed, forming a Z-transfer path, which effectively delays the compounding of the electron-hole pairs (e-/h+) and further improves the sensitivity of the sensor. The minimum detection threshold of the PEC sensor is 26.58 fg/mL, and the feasibility of real samples is investigated, providing new insights for early diagnosis and prognostic treatment of diseases.

Unveiling the X-ray polarimetric properties of LMC X−3 with IXPE, NICER, and Swift/XRT

ABSTRACT The incoming Imaging X-ray Polarimetry Explorer (IXPE) observations of X-ray binaries provide a new tool to investigate the underlying accretion geometry. Here, we report the first measurements of X-ray polarization of the extragalactic black-hole X-ray binary LMC X−3. We find a polarization fraction of $\sim 3~{{\ \rm per\ cent}}$ at a polarization angle of ∼135° in the 2–8 keV energy band with statistical significance at the 7σ level. This polarization measurement significantly exceeds the minimum detectable polarization threshold of 1.2 per cent for the source, ascertained at a 99 per cent confidence level within the 2–8 keV energy band. The simultaneous spectro-polarimetric fitting of Neutron Star Interior Composition Explorer, Swift/X-Ray Telescope (XRT), and IXPE revealed the presence of a disc with a temperature of ∼1 keV and a Comptonized component with a power-law index of ∼2.4, confirming the soft nature of the source. The polarization degree increases with energy from ∼3 per cent in the 2–5.7 keV band to ∼9 per cent in the 5.7–8 keV band, while the polarization angle is energy independent. The observed energy dependence and the sudden jump of polarization fraction above 5 keV supports the idea of a static slab coronal geometry for the Comptonizing medium of LMC X−3.

Establishment and Application Prospect of Reverse Transcriptase Recombinase-Aided Amplification Assay for Subgroup C Avian Metapneumovirus.

Among broilers, the main pathogen that leads to swollen head syndrome (SHS) is the subgroup C avian metapneumovirus (aMPV-C). The aMPV-C infection can lead to an upsurge in the rate of soft-shell eggs, resulting in reduced egg production and seriously affecting the economy of the livestock industry. Therefore, a rapid method for aMPV-C detection needs to be invented. According to the N gene of aMPV-C, we designed the specific probe and primer and created a reverse transcription recombinase-aided amplification assay (RT-RAA) for the detection of aMPV-C. aMPV-C could be detected quickly and specifically by this method at 41 °C for 30 min. The sensitivity assay inferred that the minimum detection threshold of RT-RAA was 3.38 × 101 copies/μL. A specificity assay showed that the RT-RAA method did not cross-react with other subgroups (aMPV-A, aMPV-B, aMPV-D) or other viruses (H9N2, NDV, IBV, IBDV). Forty samples of known clinical background were tested by RT-RAA and RT-qPCR. The two approaches had a 100% correlation rate. In conclusion, this research successfully created an RT-RAA assay for aMPV-C.

Associations between fat taste sensitivity, nutritional intakes, body mass index and papillae density in healthy Algerian women: A cross-sectional study

Introduction: This study aimed to evaluate the link between nutritional intake, fat taste sensitivity, papillae density, and body mass index (BMI) in the Algerian women population. Methods: This work is a cross-sectional study; 140 women were recruited. Weight, height, and waist circumference were measured. Detection thresholds for oleic acid (OA) were determined according to three alternative forced choice method. Based on the cumulative distribution of minimum detection thresholds, participants were classified into hyposensitive ≥ 3 mM and hypersensitive < 3 mM. Food intakes were recorded using 24-hour diaries on three different days. Fatty food consumption frequencies were studied using a frequency consumption survey. Papillae density was determined by tongue photography. Statistical analysis was performed with SPSS software version 25. Results: Our results indicated that 50 % of our population was overweight including 27 % of obesity. Average OA detection thresholds were greater in overweight and obese subjects compared to normal-weight subjects (p ˂ 0.001). A positive correlation was found between OA detection thresholds and BMI and waist circumference (p ˂ 0.001). Hyposensitive subjects consumed more energy and fat intake compared to hypersensitive subjects. Papillae density was inversely associated with BMI and OA detection thresholds. Conclusions: The study confirms the association between fat taste sensitivity and weight status in Algerian women. Overweight and/or obese participants were the least sensitive to OA compared to normal-weight participants. Hyposensitive subjects had higher intakes of energy and lipids compared to hypersensitive subjects. They also expressed a lower number of fungiform papillae. Overweight participants also had a lower number of fungiform papillae compared to normal-weight participants. A better understanding of the links between the detection of dietary lipids and energy/fat intakes in obese subjects may lead to new nutritional strategies to limit the risk of obesity.

Monte-carlo simulation of the effective lunar aperture for detection of ultra-high energy neutrinos with LOFAR

Ultra-high-energy (UHE) cosmic neutrinos interacting with the Moon’s regolith generate particle showers that emit Askaryan radiation. This radiation can be observed from the Earth using ground-based radio telescopes like LOFAR. We simulate the effective detection aperture for UHE neutrinos hitting the Moon. Under the same assumptions, results from this work are in good agreement with previous analytic parameterizations and Monte Carlo codes. The dependence of the effective detection aperture on the observing parameters, such as observing frequency and minimum detection threshold, and lunar characteristics like surface topography have been studied. Using a Monte Carlo simulation, we find that the detectable neutrino energy threshold is lowered when we include a realistic treatment of the inelasticity, transmission coefficient, and surface roughness. Lunar surface roughness at large scales enhances the total aperture for higher observation frequencies (ν≥1GHz\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ u \\ge 1~\ extrm{GHz}$$\\end{document}) but has no significant effect on the LOFAR aperture. However, roughness at scales small compared to the wavelength reduces the aperture at all frequencies.

Adaptive photoperiod interpretation modulates phenological timing in Atlantic salmon

Photoperiod, the portion of 24-h cycle during which an organism is exposed to illumination, is an important phenological cue in many animals. However, despite its influence on critical biological processes, there remain many unknowns regarding how variations in light intensity translate into perceived photoperiod. This experiment examined how light intensity variations affect perceived photoperiod in Atlantic salmon (Salmo salar) to determine whether photoperiod interpretation is, a) fixed such that anything above a minimum detection threshold is regarded as ‘illumination’, or b) adaptive and varies with recent light exposure. To do this we compared the frequency of smoltification and sexual maturation between groups of male parr which were exposed to one of eight light regimes on a 12:12 cycling regime (12-hour day/12-hour night). The eight regimes were divided into two treatments, four with ‘High’ daytime light intensity and four with ‘Low’ daytime light intensity. The ‘High' and ‘Low' intensity treatments were each sub-divided into four groups for which the subjective ‘night’ light intensity was 100%, 10%, 1% and 0% of the daytime light intensity, with four replicate tanks of each treatment. The results show that above a minimum detection threshold, Atlantic salmon have adaptive photoperiod interpretation which varies with recent light exposure, and that adaptive photoperiod interpretation modulates the timing of the parr-smolt transformation and sexual maturation. Further, we show that photoperiod interpretation varies between closely related families. Given the influence of phenological timing on species survival, our results reveal a critical role for integration of photoperiod interpretation in attempts to understand how geographically shifting thermal niches due to climate change will affect future populations.

Nucleation kinetics-based solvent selection for the liquid antisolvent crystallization of a lipophilic intermediate

The fundamental understanding of solubility and nucleation kinetics are two primary pillars for liquid antisolvent crystallization (LASC) process development. In our present work, the solubility of intermediate A in four different solvents and binary mixtures with water, in the temperature range from 273 K to 323 K, was determined using a liquid chromatographic method to acquire the fundamental thermodynamic information for the LASC process. Intermediate A was monitored both in the solid phase and in the liquid phase by in line Raman spectroscopy. The importance of selection of the optimum scale and mixing conditions (volume and fluid dynamics dependency) for conducting metastable zone width (MSZW) measurements for the nucleation kinetics study, due to stochastic nature of nucleation, has been demonstrated to translate the findings to larger industrial scales. The 3.5 mL volume in reactor with a 3 blade downflow overhead impeller in the Crystalline™ (Technobis) was found to be an optimal platform for the data generation for the extraction of nucleation kinetics. The minimum detection threshold value (fN) reported in the literature was experimentally derived for the intermediate A-solvent systems used, covering the effect of supersaturation, reaction volume and agitation rate. The combined polythermal and antisolvent addition approach was applied to determine MSZWs and, subsequently, the kinetic parameters were estimated based on both linearized integral and 3D nucleation models. It was demonstrated how the derived parameters complemented with accurate solubility data are required to guide solvent selection for bottom-up generation of nanosuspensions. The findings were validated by conducting batch and continuous LASC of intermediate A. Particle size distributions derived from electron scanning microscopy obtained at similar driving forces confirmed the solvents selection order based on their nucleation tendency of dissolved intermediate A. These results serve as an example for applying a nucleation kinetics-based fundamental approach for solvent selection in the development of LASC process for generation of long-acting injectable suspensions.

Understanding the potential of Sentinel-2 for monitoring methane point emissions

Abstract. The use of satellite instruments to detect and quantify methane emissions from fossil fuel production activities is highly beneficial to support climate change mitigation. Different hyperspectral and multispectral satellite sensors have recently shown potential to detect and quantify point-source emissions from space. The Sentinel-2 (S2) mission, despite its limited spectral design, supports the detection of large emissions with global coverage and high revisit frequency thanks to coarse spectral coverage of methane absorption lines in the shortwave infrared. Validation of S2 methane retrieval algorithms is instrumental in accelerating the development of a systematic and global monitoring system for methane point sources. Here, we develop a benchmarking framework for such validation. We first develop a methodology to generate simulated S2 datasets including methane point-source plumes. These benchmark datasets have been created for scenes in three oil and gas basins (Hassi Messaoud, Algeria; Korpeje, Turkmenistan; Permian Basin, USA) under different scene heterogeneity conditions and for simulated methane plumes with different spatial distributions. We use the simulated methane plumes to validate the retrieval for different flux rate levels and define a minimum detection threshold for each case study. The results suggest that for homogeneous and temporally invariant surfaces, the detection limit of the proposed S2 methane retrieval ranges from 1000 to 2000 kg h−1, whereas for areas with large surface heterogeneity and temporal variations, the retrieval can only detect plumes in excess of 500 kg h−1. The different sources of uncertainty in the flux rate estimates have also been examined. Dominant quantification errors are either wind-related or plume mask-related, depending on the surface type. Uncertainty in wind speed, both in the 10 m wind (U10) and in mapping U10 to the effective wind (Ueff) driving plume transport, is the dominant source of error for quantifying individual plumes in homogeneous scenes. For heterogeneous and temporally variant scenes, the surface structure underlying the methane plume affects the plume masking and can become a dominant source of uncertainty.

Ossified Particles in the Peripheral Circulation of Young and Old male Fischer‐344 Rats following Bone Marrow Ablation and Interleukin‐1 Receptor Antagonism

BACKGROUNDA pro‐inflammatory marrow microenvironment presumably augments ossification in bone marrow blood vessels. We speculate that ossifying blood vessels results in bone‐like particles (i.e., ossified particles, OSP) in the peripheral blood. By performing bone marrow ablation (BMA) and administering an interleukin‐1 receptor antagonist (IL‐1RA) during recovery, we sought to reduce the number of OSP in the circulation.METHODSYoung (6‐mon) and old (24‐mon) male Fischer‐344 rats were assigned accordingly: Control (young CON, n=10; old CON, n=8), IL‐1RA (young, n=11; old, n=8), BMA (young, n=12; old, n=7) and combined treatment (young IL‐1RA+BMA, n=8; old IL‐1RA+BMA, n= 8). In the BMA and IL‐1RA+BMA rats, bone marrow in the right femoral shaft was ablated. During 3 weeks of recovery, CON and BMA rats received PBS (100 μL, 3 d/wk, i.p.), while IL‐1RA and IL‐1RA+BMA rats received the antagonist (3 μg/kg, 3 d/wk, i.p.). At sacrifice, left ventricular whole blood samples were collected. Plasma IL‐1α and IL‐1β were measured by ELISA. Five‐hundred microliters of blood were prepared for flow cytometry and OSP were sorted to obtain a count. The diameters of OSP were determined with a Cellometer. Some samples were pooled to meet the minimum detection threshold. These data are expressed as a percent of the total OSP count according to diameter, i.e., % OSP per 0‐14µm, 15‐30µm, 31‐45µm, and 46‐60µm. ELISA data were analyzed by two‐way ANOVA using SPSS (v. 25). The OSP count distributions were highly positively skewed with a mean and variance indicating overdispersed data. Therefore, negative binomial models were used to compare OSP count and % OSP using SAS GENMODE (v. 9.4). Data are presented as Means ± Standard Error.RESULTSMain effects for Age and Condition were detected in the ELISAs. Plasma IL‐1α did not differ; however, IL‐1β was higher (p<0.05) in Old (30.8±4.6 pg/mL) vs. Young (15.0±4.3 pg/mL). For Condition, IL‐1RA+BMA (49.6±14.1 pg/mL) had higher (p<0.05) plasma IL‐1α vs. CON (7.5E‐15±12.7 pg/mL) and IL‐1RA (9.4±13.2 pg/mL), and both CON (31.7±6.1 pg/mL) and IL‐1RA (41.2±6.3 pg/mL) had higher plasma IL‐1β vs. BMA (6.5±5.8 pg/mL) and IL‐1RA+BMA (12.3±6.8 pg/mL). For the OSP, Age x Condition interactions were detected. OSP count was higher (p<0.05) in Old IL‐1RA+BMA (3977±1631) vs. all other groups except Old IL‐1RA (1422±476). In addition, OSP count was higher (p<0.05) in Old IL‐1RA vs. Young IL‐1RA (212±67), Young BMA (276±80), and Young IL‐1RA+BMA (298±106). OSP count did not differ between Young CON (399±134) and Old CON (561±199). Analysis of % OSP revealed a main effect for diameter. Of the total in circulation, 38.4±7.8% were 15‐30µm, higher (p<0.05) than those 31‐45µm (5.7±1.2%) and 46‐60µm (2.2±0.5%). In addition, the % OSP 0‐14 µm (25.7±3.8%) were higher (p<0.05) vs. 31‐45µm and 45‐60µm. Further, the % OSP 31‐45µm was higher (p<0.05) vs. 46‐60µm.CONCLUSIONPlasma concentrations of IL‐1α and IL‐1β varied with age and condition. Treatment with the IL‐1RA in old rats exacerbated the number of OSP in circulation, with the combined treatment (i.e., IL‐1RA+BMA) having the most dramatic effects. The majority of circulating OSP were 15‐30 µm in diameter, i.e., diameters amenable to embolism.

Cross-Cultural adaptation and validation of the Exercise-Induced Leg Pain questionnaire for Spanish speaking patients

Objectives To cross-culturally adapt and validate a Spanish version of the Exercise-Induced Leg Pain questionnaire. Design Clinical measurement study. Participants The validity and reliability of the adapted version were assessed in four groups of 40 patients with exercise-induced leg pain, 40 physically active healthy individuals (control group), 40 athletes with other leg conditions and 40 athletes, military personnel and candidates with no history of injury (risk group). Main measure Exercise-Induced Leg Pain questionnaire. Reference measures Spanish version of the Short-Form 36 and Schepsis postsurgical classification scale. Results In patients with exercise-induced leg pain, the mean age was 24.9 (± 6.7) years and the mean score of the questionnaire was 62.8 (± 10.9). The standard error of measurement and minimum detectable change threshold were 1.67 and 4.63 points, respectively. Excellent internal consistency (Cronbach’s α = 0.942) and test-retest reliability (intraclass correlation coefficient = 0.995) were found. The exploratory and confirmatory factor analyses indicated that a one-factor solution explained 66.84% of the variance. For construct validity, 87.5% of the previously stated hypotheses were fulfilled between the total score of the questionnaire and Short-Form 36 dimensions. Concurrent validity, assessed by the Schepsis scale, was almost perfect (r = 0.92, p < 0.001). The predictive validity of the questionnaire was demonstrated using the receiving operating curve (area of 0.992; 95% CI: 0.983–1, p < 0.001). Conclusion The Spanish version of the Exercise-Induced Leg Pain questionnaire resulted in a reliable and valid instrument to assess patients with exercise-induced leg pain.

The Value of Whole-Genome Sequencing for Mitochondrial DNA Population Studies: Strategies and Criteria for Extracting High-Quality Mitogenome Haplotypes.

Whole-genome sequencing (WGS) data present a readily available resource for mitochondrial genome (mitogenome) haplotypes that can be utilized for genetics research including population studies. However, the reconstruction of the mitogenome is complicated by nuclear mitochondrial DNA (mtDNA) segments (NUMTs) that co-align with the mtDNA sequences and mimic authentic heteroplasmy. Two minimum variant detection thresholds, 5% and 10%, were assessed for the ability to produce authentic mitogenome haplotypes from a previously generated WGS dataset. Variants associated with NUMTs were detected in the mtDNA alignments for 91 of 917 (~8%) Swedish samples when the 5% frequency threshold was applied. The 413 observed NUMT variants were predominantly detected in two regions (nps 12,612–13,105 and 16,390–16,527), which were consistent with previously documented NUMTs. The number of NUMT variants was reduced by ~97% (400) using a 10% frequency threshold. Furthermore, the 5% frequency data were inconsistent with a platinum-quality mitogenome dataset with respect to observed heteroplasmy. These analyses illustrate that a 10% variant detection threshold may be necessary to ensure the generation of reliable mitogenome haplotypes from WGS data resources.

Link between SARS-CoV-2 emissions and airborne concentrations: Closing the gap in understanding

The airborne transmission of SARS-CoV-2 remains surprisingly controversial; indeed, health and regulatory authorities still require direct proof of this mode of transmission. To close this gap, we measured the viral load of SARS-CoV-2 of an infected subject in a hospital room (through an oral and nasopharyngeal swab), as well as the airborne SARS-CoV-2 concentration in the room resulting from the person breathing and speaking. Moreover, we simulated the same scenarios to estimate the concentration of RNA copies in the air through a novel theoretical approach and conducted a comparative analysis between experimental and theoretical results. Results showed that for an infected subject's viral load ranging between 2.4 × 106 and 5.5 × 106 RNA copies mL-1, the corresponding airborne SARS-CoV-2 concentration was below the minimum detection threshold when the person was breathing, and 16.1 (expanded uncertainty of 32.8) RNA copies m-3 when speaking. The application of the predictive approach provided concentrations metrologically compatible with the available experimental data (i.e. for speaking activity). Thus, the study presented significant evidence to close the gap in understanding airborne transmission, given that the airborne SARS-CoV-2 concentration was shown to be directly related to the SARS-CoV-2 emitted. Moreover, the theoretical analysis was shown to be able to quantitatively link the airborne concentration to the emission.

The Study of Calibration for the Hybrid Pixel Detector With Single Photon Counting in HEPS-BPIX

The calibration process for a hybrid pixel detector designed for the High Energy Photon Source in China, called HEPS-BPIX, is presented in this article. The relationship between the energy and threshold is quantified for the threshold calibration based on a threshold scanning. For threshold trimming, a precise algorithm based on local digital to analog converter (LDAC) characteristics and a fast algorithm based on LDAC scanning are proposed in this article to study the performance of threshold digital to analog converters (DACs) that will be applied to pixels. The threshold dispersion was reduced from 46.28 mV without the algorithm to 6.78 mV with the precise algorithm, whereas it was 7.61 mV with the fast algorithm. For temperatures from 5 °C to 60 °C, the threshold dispersion of the precise algorithm varies in the range of 5.69 mV. In contrast, it is 33.21 mV with the fast algorithm, which can be recorrected to 1.49 mV. The measurement results show that the fast algorithm could obtain the applicable threshold dispersion for a silicon pixel module and took less time. In comparison, the precise algorithm could obtain better threshold dispersion but was time-consuming. The temperature dependence of the silicon pixel module noise was also studied to assess the detector working status. The minimum detectable energy threshold could be reduced to 0.83-4.36 keV at a temperature of 5 °C.

Effects of exercise on browning of adipose tissue in OLETF rat

Browning of subcutaneous white adipose tissue (WAT) is induced by stimulation of β3 adrenergic receptor agonist with cold exposure and exercise training. However, it is remained unknown whether browning of adipose tissue equally inducing between obesity and non-obesity. The purpose of the present study was to investigate the effects of exercise on browning of adipose tissue in obesity. Male Otsuka Long-Evans Tokushima fatty (OLETF) rats and Long-Evans Tokushima Otsuka (LETO) rats were used as models of obesity and non-obesity, respectively. The rats were divided into exercise and sedentary groups. The rats of exercise groups were placed in the cages with a running wheel for 12 h (20:00 to 8:00 h) daily from 19 to 21 weeks of age. Food and water were provided ad libitum. There were no significant differences in the amount of voluntary wheel running between animal strains. Although there were no significant differences in the expression level of uncoupling protein 1 (UCP1) of brown adipose tissue (BAT) between the exercise and sedentary groups of LETO rats, the expression levels were significantly higher in the exercise group than the sedentary group of OLETF rats. In the inguinal WAT, the expression levels of UCP1 were below the minimum detectable threshold among all groups in both strains. These results suggest differential sensitivity of activation of UCP1 in BAT between obesity and non-obesity. In addition, one of the reasons for undetectable exercise-induced UCP1 expression in the WAT could be due to the low intensity by voluntary wheel running. This study was approved by the Institutional Animal Care and Use Committee of Hiroshima University (A19-163) and conducted in accordance with the Hiroshima University Regulations for Animal Experimentation. All experiments complied with the National Institute of Health Guidelines for the Care and Use of Laboratory Animals.

Commercial kefir products assessed for label accuracy of microbial composition and density

Kefirs are fermented beverages containing yeast and bacteria produced by the fermentation of water or milk with kefir grains. Because microorganism density may influence a product's health benefits, label accuracy regarding viable bacterial density and taxonomy of fermented foods is important. In this study, the microbiota of 5 commercial kefir products were measured quantitatively using standard plating techniques and characterized using high-resolution, long-read 16S rRNA gene amplicon sequencing. To enumerate viable lactic acid bacteria, 2 lots of each product were plated on de Man, Rogosa and Sharpe agar upon opening and following 14 d and incubated under anaerobic and aerobic conditions. Results revealed that 66% of products with a guaranteed count of colony-forming units per gram overstated microorganism density by at least 1 log, with only product E exceeding 1 × 109 cfu/g. Sequencing results demonstrated moderate product label accuracy in regard to taxonomy, yet several products contained bacterial species above the minimum detectable threshold (0.001% relative abundance) that were not included on the labels (e.g., Streptococcus salivarius, Lactobacillus paracasei). Our results demonstrate a moderate level of labeling accuracy for commercial kefir products intended for human consumption. Regulatory agencies and consumers must continue to scrutinize these products and demand a higher level of accuracy and quality.

Using reproductive hormone concentrations from the muscle of white sharks Carcharodon carcharias to evaluate reproductive status in the Northwest Atlantic Ocean

Novel, non-lethal approaches are needed to improve our current understanding of the reproductive biology and ecology of the white shark Carcharodon carcharias. Previous studies have demonstrated that concentrations of reproductive hormones in muscle tissue can be used as reliable indicators of reproductive status for many vertebrate species, including elasmobranchs. Here, we applied this method to assess the concentrations of testosterone (T) and estradiol (E2) in muscle biopsies from free-swimming white sharks at a known aggregation site off the coast of Cape Cod, Massachusetts (USA), in the Northwest Atlantic Ocean, to determine whether this technique could be used to evaluate the reproductive status of this species. A total of 14 muscle samples from 13 white sharks (7 males [1 sampled twice], 6 females), ranging in size from 3.3 to 4.2 m total length, were analyzed for this study. T and E2 were present in sufficient amounts to be quantified in 7 of the 8 (87.5%) male and 1 of the 6 (16.7%) female samples, respectively. As expected, most samples collected from immature individuals were below minimum detection thresholds. Hormone concentrations in males presumed to be adults were also generally low, suggesting these individuals were not actively producing sperm at the time of sample collection. Overall, the results herein are similar to those found in other species and indicate that concentrations of hormones in the skeletal muscle of subadult and adult white sharks can provide information on the reproductive status of individuals. This technique could have wide-ranging applications for the study of white shark reproduction in the future.

Quantification of Pseudomonas protegens FD6 and Bacillus subtilis NCD-2 in soil and the wheat rhizosphere and suppression of root pathogenic Rhizoctonia solani AG-8

Bacillus subtilis strain NCD-2 and Pseudomonas protegens strain FD6 produce a range of antimicrobial metabolites known to be effective against soil-borne plant pathogens. Quantitative qPCR assays were designed from sequence characterized amplified fragment length polymorphisms (AFLP) diagnostic for each inoculant genotype. The qPCR minimum detection thresholds (MDT) for NCD-2 and FD6 ranged between 5.2 × 103 (log 3.71) and 1.5 × 106 (log 6.18) genome (cell) equivalents g−1 of soil or wheat root tissue and were independent of soil type. Wheat rhizosphere populations of strains FD6 and NCD-2 significantly declined during the first 14 days postinoculation and then remained stable for the next 14 days. Colonization of wheat roots, rhizosphere soil and bulk (non-rhizosphere) soil by FD6 was significantly greater than that of NCD-2. Strains FD6 and NCD-2 significantly decreased in vitro growth of wheat root pathogenic Rhizoctonia solani AG-8, Pythium irregulare and Gaeumannomyces graminis var. tritici, fungal antibiosis by FD6 greater than NCD-2. Wheat rhizosphere colonization by NCD-2 and FD6 significantly decreased abundance of R. solani AG-8 in the rhizosphere by 3- and 13-fold respectively, pathogen suppression increasing (21%–29%) foliar biomass of wheat seedlings to levels not significantly different to the non-diseased control. The qPCR assays developed in this study were used to monitor soil and rhizosphere populations of P. protegens FD6 and B. subtilis NCD-2 and their suppressive efficacies against R. solani AG-8 in wheat. These assays can be applied to monitor the dynamics of these inoculants in suppressing Rhizoctonia root rot and other crop diseases.

A Novel Direction-of-Arrival Estimation Algorithm Without Knowing the Source Number

As the eigenvalue ranking problem is analyzed, a direction-of-arrival (DOA) estimation method without knowing the number of sources is proposed. The proposed method is utilized through ranking the eigenvalue of specific covariance matrix to get the smallest eigenvalue and construct a new spatial spectrum. By deducing the novel algorithm, the mapping between the eigenvalues and power of signals is presented. Using the mapping, the minimum detection threshold for this algorithm is derived. Besides, the reason for the formation of pseudo-peaks is interpreted, and an approach to parameter selection is provided. The validity of the related theory of the algorithm is further investigated by simulations.