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At least 19 recordsLinked to original sources
PubMed2024

Genetic characterization and selection of litter size traits of Guizhou Black goat and Meigu goat.

The aim of this study is to explore the genetic characteristics of Guizhou Black goats and Meigu goats and their relationship to reproductive performance through population structure analysis, genetic diversity assessment, and selection signal analysis. Blood samples of 19 Guizhou Black goats and 11 Meigu goats were collected for whole-genome high-throughput sequencing. Using PCA and ADMIXTURE analyses, their population structure and genetic relationships were revealed. Further genetic diversity analysis showed that although there is significant population differentiation, the levels of genetic diversity are similar. Subsequently, these goats were categorized into high-yield and low-yield groups based on their litter sizes, with 15 goats in each group. Then, a selection signal analysis was performed using FST and π ratios for 33,563 SNP loci. The results identified six candidate genes, including KCNIP4, GFRA2, and DGKH, which are significantly associated with high litter performance. These findings enhanced our understanding of the genetic characteristics and population structure of Guizhou Black goats and Meigu goats. Moreover, they provide an important theoretical foundation and scientific basis for further breeding improvements.

Animals↗
PubMed2025

Landscape genomics analysis reveals the genetic basis underlying cashmere goats and dairy goats adaptation to frigid environments.

Understanding the genetic mechanism of cold adaptation in cashmere goats and dairy goats is very important to improve their production performance. The purpose of this study was to comprehensively analyze the genetic basis of goat adaptation to cold environments, clarify the impact of environmental factors on genome diversity, and lay the foundation for breeding goat breeds to adapt to climate change. A total of 240 dairy goats were subjected to genome resequencing, and the whole genome sequencing data of 57 individuals from 6 published breeds were incorporated. By integrating multiple approaches such as phylogenetic analysis, population structure analysis, gene flow and population history exploration, selection signal analysis, and genome-environment association analysis, an in-depth investigation was carried out. Phylogenetic analysis unraveled the genetic relationships and differentiation patterns among dairy goats and other goat breeds. Through signal analysis (θπ, FST, XP-CLR), we identified numerous candidate genes associated with cold adaptation in dairy goats (STRIP1, ALX3, HTR4, NTRK2, MRPL11, PELI3, DPP3, BBS1) and cashmere goats (MED12L, MARC2, MARC1, DSG3, C6H4orf22, CHD7, MYPN, KIAA0825, MITF). Genome-environment association (GEA) analysis confirmed the link between these genes and environmental factors. Moreover, a detailed analysis of the critical genes C6H4orf22 and STRIP1 demonstrated their significant roles in the geographical variations of cold adaptation and allele frequency differences among different breeds. This study contributes to understanding the genetic basis of cold adaptation, providing crucial theoretical support for precision breeding programs aimed at improving production performance in cold regions by leveraging adaptive alleles, thereby ensuring sustainable animal husbandry.

Environmental adaptation↗
PubMed2005

Is the method of signal analysis and test selection important for measuring standing balance in subjects with persistent whiplash?

Dizziness and or unsteadiness, associated with episodes of loss of balance, are frequent complaints in those suffering from persistent problems following a whiplash injury. Research has been inconclusive with respect to possible aetiology, discriminative tests and analyses used. The aim of this pilot research was to identify the test conditions and the most appropriate method for the analysis of sway that may differentiate subjects with persistent whiplash associated disorders (WAD) from healthy controls. The six conditions of the Clinical Test for Sensory Interaction in Balance was performed in both comfortable and tandem stance in 20 subjects with persistent WAD compared to 20 control subjects. The analyses were carried out using a traditional method of measurement, total sway distance, to results obtained from the use of wavelet analysis. Subjects with WAD were significantly less able to complete the tandem stance tests on a firm surface than controls. In comfortable stance, using wavelet analysis, significant differences between subjects with WAD and the control group were evident in total energy of the trace for all test conditions apart from eyes open on the firm surface. In contrast, the results of the analysis using total sway distance revealed no significant differences between groups across all six conditions. Wavelet analysis may be more appropriate for detecting disturbances in balance in whiplash subjects because the technique allows separation of the noise from the underlying systematic effect of sway. These findings will be used to direct future studies on the aeitiology of balance disturbances in WAD.

Adult↗
PubMed2007

Comparison of multivariate calibration models for glucose, urea, and lactate from near-infrared and Raman spectra.

Partial least-squares (PLS) calibration models have been generated from a series of near-infrared (near-IR) and Raman spectra acquired separately from sixty different mixed solutions of glucose, lactate, and urea in aqueous phosphate buffer. Independent PLS models were prepared and compared for glucose, lactate, and urea. Near-IR and Raman spectral features differed substantially for these solutes, with Raman spectra enabling greater distinction with less spectral overlap than features in the near-IR spectra. Despite this, PLS models derived from near-IR spectra outperformed those from Raman spectra. Standard errors of prediction were 0.24, 0.11, and 0.14 mmol L(-1) for glucose, lactate, and urea, respectively, from near-IR spectra and 0.40, 0.42, and 0.36 mmol L(-1) for glucose, lactate, and urea, respectively, from Raman spectra. Differences between instrumental signal-to-noise ratios were responsible for the better performance of the near-IR models. The chemical basis of model selectivity was examined for each model by using a pure component selectivity analysis combined with analysis of the net analyte signal for each solute. This selectivity analysis showed that models based on either near-IR or Raman spectra had excellent selectivity for the targeted analyte. The net analyte signal analysis also revealed that analytical sensitivity was higher for the models generated from near-IR spectra. This is consistent with the lower standard errors of prediction.

Calibration↗
PubMed1997

Residues in the membrane-spanning and extracellular loop regions of the parathyroid hormone (PTH)-2 receptor determine signaling selectivity for PTH and PTH-related peptide.

The parathyroid hormone (PTH)-2 receptor displays strong ligand selectivity in that it responds fully to PTH but not at all to PTH-related peptide (PTHrP). In contrast, the PTH-1 receptor (PTH/PTHrP receptor) responds fully to both ligands. Previously it was shown that two divergent residues in PTH and PTHrP account for PTH-2 receptor selectivity; position 23 (Trp in PTH and Phe in PTHrP) determines binding selectivity and position 5 (Ile in PTH and His in PTHrP) determines signaling selectivity. To identify sites in the PTH-2 receptor involved in discriminating between His5 and Ile5, we constructed PTH-2 receptor/PTH-1 receptor chimeras, expressed them in COS-7 cells, and tested for cAMP responsiveness to [Trp23] PTHrP-(1-36), and to the nondiscriminating peptide [Ile5, Trp23]PTHrP-(1-36) (the Phe23 --> Trp modification enabled high affinity binding of each ligand to the PTH-2 receptor). The chimeras revealed that the membrane-spanning/loop region of the receptor determined His5/Ile5 signaling selectivity. Subsequent analysis of smaller cassette substitutions and then individual point mutations led to the identification of two single residues that function as major determinants of residue 5 signaling selectivity. These residues, Ile244 at the extracellular end of transmembrane helix 3, and Tyr318 at the COOH-terminal portion of extracellular loop 2, are replaced by Leu and Ile in the PTH-1 receptor, respectively. The results thus indicate a functional interaction between two residues in the core region of the PTH-2 receptor and residue 5 of the ligand.

Amino Acid Sequence↗
PubMed1986

Improved selection of patients for programmed ventricular stimulation by frequency analysis of signal-averaged electrocardiograms.

Improved selection of patients with suspected sustained ventricular tachycardia (VT) for programmed ventricular stimulation is needed. To determine if frequency analysis detects patients in whom sustained VT might be induced, we first obtained fast-Fourier transforms (FFT) of signal-averaged electrocardiograms (ECGs) from 20 patients with spontaneous sustained VT (group 1) and compared them with the results of programmed ventricular stimulation with single and double extrastimuli during two cycle lengths and burst pacing from two right ventricular sites. The FFT data were expressed as an area ratio that quantified the relative contributions of 20 to 50 Hz frequencies in the terminal QRS and ST segment. A logistic regression with inducibility as the dependent variable was used to help define area ratio values greater than 20 as abnormal. Sustained monomorphic VT was induced in 18 patients, each with an area ratio value greater than 20. Sustained VT was not induced in two patients, each with an area ratio value less than 20. FFT data were then compared prospectively with the results of programmed stimulation in 38 patients (group II) with nonsustained VT (12 patients) or syncope (26 patients) referred for electrophysiologic study. In none of the 26 patients in group II with normal FFT values was VT inducible. Sustained monomorphic VT was induced in five of 12 patients with abnormal FFT values. Thus, the results of FFT analysis correctly predicted the results of programmed ventricular stimulation in 88% of patients studied and in 82% of patients in group II with syncope or nonsustained VT. Moreover, all five patients in group II in whom sustained VT was induced were identified correctly.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2006

A metabonomic study of transgenic maize (Zea mays) seeds revealed variations in osmolytes and branched amino acids.

The aim of the research was to investigate metabolic variations associated with genetic modifications in the grains of Zea mays using metabonomic techniques. With this in mind, the non-targeted characteristic of the technique is useful to identify metabolites peculiar to the genetic modification and initially undefined. The results obtained showed that the genetic modification, introducing Cry1Ab gene expression, induces metabolic variations involving the primary nitrogen pathway. Concerning the methodological aspects, the experimental protocol used has been applied in this field for the first time. It consists of a combination of partial least square-discriminant analysis and principal component analysis. The most important metabolites for discrimination were selected and the metabolic correlations linking them are identified. Principal component analysis on selected signals confirms metabolic variations, highlighting important details about the changes induced on the metabolic network by the presence of a Bt transgene in the maize genome.

Amino Acids, Branched-Chain↗
PubMed1979

Perceptual origins of the phoneme boundary effect and selective adaptation to speech: a signal detection theory analysis.

Differences in discriminability of stimuli near phoneme boundaries and findings from selective adaptation have been used to argue for the existence of neurophysiological mechanisms--feature detectors--which mediate the perception of speech and speechlike sounds. A detection theory model was used in order to discover whether or not the phoneme boundary effect and the shift in phoneme boundary after adaptation might rather be attributable to changes in response bias. This model was applied in the analysis of phoneme identifications of three sets of stimuli before and after adaptation. While the origins for the phoneme boundary effect appear to lie below the level of response bias, findings suggest that identification changes after adaptation may be due solely to shifts in criterion, rather than changes at the sensory level.

Adult↗
PubMed2002

Habitat-dependent song divergence in the little greenbul: an analysis of environmental selection pressures on acoustic signals.

Bird song is a sexual trait important in mate choice and known to be shaped by environmental selection. Here we investigate the ecological factors shaping song variation across a rainforest gradient in central Africa. We show that the little greenbul (Andropadus virens), previously shown to vary morphologically across the gradient in fitness-related characters, also varies with respect to song characteristics. Acoustic features, including minimum and maximum frequency, and delivery rate of song notes showed significant differences between habitats. In contrast, we found dialectal variation independent of habitat in population-typical songtype sequences. This pattern is consistent with ongoing gene flow across habitats and in line with the view that song variation in the order in which songtypes are produced is not dependent on habitat characteristics in the same way physical song characteristics are. Sound transmission characteristics of the two habitats did not vary significantly, but analyses of ambient noise spectra revealed dramatic and consistent habitat-dependent differences. Matching between low ambient noise levels for low frequencies in the rainforest and lower minimal frequencies in greenbul songs in this habitat suggests that part of the song divergence may be driven by habitat-dependent ambient noise patterns. These results suggest that habitat-dependent selection may act simultaneously on traits of ecological importance and those important in prezygotic isolation, leading to an association between morphological and acoustic divergence. Such an association may promote assortative mating and may be a mechanism driving reproductive divergence across ecological gradients.

Animals↗
PubMed1992

Selecting a stimulus signal for linear systems analysis of the vestibulo-ocular reflex.

We evaluated 3 types of stimulus signals for use in estimating the transfer function of the vestibulo-ocular reflex. We used individual sine-wave, sum-of-sine, and pseudorandom stimuli. Five normal human subjects were tested 5 times each using each of the 3 stimulus types. Frequency domain techniques were used to estimate the transfer function at 0.01, 0.03, and 0.05 Hz. The most consistent estimates were obtained using individual sine-wave stimuli. The pseudorandom signal yielded the most variable estimates. A sum-of-sine stimulus composed of 3 sine-wave signals provided estimates slightly more variable than the individual sine-wave stimuli, but much less variable than the pseudorandom stimulus. The redundency of the sine and sum-of-sine stimuli seems to be an advantage by providing stable estimates of the transfer function in the presence of noise.

Adult↗
PubMed2006

Sensor, signal, and image informatics - state of the art and current topics.

OBJECTIVES: The number of articles published annually in the fields of biomedical signal and image acquisition and processing is increasing. Based on selected examples, this survey aims at comprehensively demonstrating the recent trends and developments. METHODS: Four articles are selected for biomedical data acquisition covering topics such as dose saving in CT, C-arm X-ray imaging systems for volume imaging, and the replacement of dose-intensive CT-based diagnostic with harmonic ultrasound imaging. Regarding biomedical signal analysis (BSA), the four selected articles discuss the equivalence of different time-frequency approaches for signal analysis, an application to Cochlea implants, where time-frequency analysis is applied for controlling the replacement system, recent trends for fusion of different modalities, and the role of BSA as part of a brain machine interfaces. To cover the broad spectrum of publications in the field of biomedical image processing, six papers are focused. Important topics are content-based image retrieval in medical applications, automatic classification of tongue photographs from traditional Chinese medicine, brain perfusion analysis in single photon emission computed tomography (SPECT), model-based visualization of vascular trees, and virtual surgery, where enhanced visualization and haptic feedback techniques are combined with a sphere-filled model of the organ. RESULTS: The selected papers emphasize the five fields forming the chain of biomedical data processing: (1) data acquisition, (2) data reconstruction and pre-processing, (3) data handling, (4) data analysis, and (5) data visualization. Fields 1 and 2 form the sensor informatics, while fields 2 to 5 form signal or image informatics with respect to the nature of the data considered. CONCLUSIONS: Biomedical data acquisition and pre-processing, as well as data handling, analysis and visualization aims at providing reliable tools for decision support that improve the quality of health care. Comprehensive evaluation of the processing methods and their reliable integration in routine applications are future challenges in the field of sensor, signal and image informatics.

Diagnostic Imaging↗
PubMed1996

Selective discrete Fourier transform algorithm for time-frequency analysis: method and application on simulated and cardiovascular signals.

The Selective Discrete Fourier transform (DFT) Algorithm [SDA] method for the calculation and display of time-frequency distribution has been developed and validated. For each time and frequency, the algorithm selects the shortest required trace length and calculates the corresponding spectral component by means of DFT. This approach can be extended to any cardiovascular related signal and provides time-dependent power spectra which are intuitively easy to consider, due to their close relation to the classical spectral analysis approach. The optimal parameters of the SDA for cardiovascular-like signals were chosen. The SDA perform standard spectral analysis on stationary simulated signals as well as reliably detect abrupt changes in the frequency content of nonstationary signals. The SDA applied during a stimulated respiration experiment, accurately detected the changes in the frequency location and amplitude of the respiratory peak in the heart rate (HR) spectrum. It also detected and quantified the expected increase in vagal tone during vagal stimuli. Furthermore, the HR time-dependent power spectrum displayed the increase in sympathetic activity and the vagal withdrawal on standing. Such transient changes in HR control would have been smeared out by standard heart rate variability (HRV), which requires consideration of long trace lengths. The SDA provides a reliable tool for the evaluation and quantification of the control exerted by the Central Nervous System, during clinical and experimental procedures resulting in nonstationary signals.

Adult↗
PubMed1997

Power spectra accuracy improvement by optimal signal epoch selection: an heuristic approach.

The problem of epoch selection in frequency analysis of biomedical signals often involves tradeoffs between the physiological system studied stationarity, the spectral resolution required, the need for dynamic investigations implying shorter epochs, etc. The accuracy of the spectra strongly depends on the epoch length. We propose a method for optimal epoch selection introducing the notion of 'quality of power spectra'. Two criteria for quantitative estimation of spectral quality are defined, considering a quality to be high when more power is concentrated in narrow frequency bands. A synthesized signal is used for describing the procedure developed and evaluating the accuracy. Noise sensitivity is assessed by adding intensive noise to the signal. Hundreds of synthesized signals are used for validation of the method and some initial experiments with heart rate variation data are presented.

Child↗
PubMed2006

Use of the 1H nuclear magnetic resonance spectra signals from polyphenols and acids for chemometric characterization of cider apple juices.

The low field region (5.8-9.0 ppm) corresponding to aromatic protons and the region 1.8-3.0 ppm of the (1)H NMR spectra were used for characterization and chemometric differentiation of 52 apple juices obtained from six cider apple varieties. The data set consisted of 14 integrated areas corresponding to resonances from acids and phenolic compounds. Multivariate procedures based on hierarchical cluster and discriminant analysis were performed on selected signals of the spectra to determine whether it was possible to distinguish the different juices. Cluster analysis was able to satisfactorily classify the six apple varieties. Discriminant analysis, by means of stepwise procedure for variables selection and leave-one-out for cross-validation, was applied to 40 samples from the year 2001, obtaining recognition and prediction abilities of 100%. The most discriminant variables corresponded to poliphenols, (-)-epicatechin, phloridzin-phloretin, and p-coumaric, chlorogenic, and malic acids. The classification model was applied to 12 samples from apples harvested in the years 2002 and 2003, and the prediction ability was 91.7%.

Beverages↗
PubMed2002

Analysis of the neuronal selectivity underlying low fMRI signals.

BACKGROUND: A prevailing assumption in neuroimaging studies is that relatively low fMRI signals are due to weak neuronal activation, and, therefore, they are commonly ignored. However, lower fMRI signals may also result from intense activation by highly selective, albeit small, subsets of neurons in the imaged voxel. We report on an approach that could form a basis for resolving this ambiguity imposed by the low (mm range) spatial resolution of fMRI. Our approach employs fMR-adaptation as an indicator for highly active neuronal populations even when the measured fMRI signal is low. RESULTS: In this study, we first showed that fMRI-adaptation is diminished when overall neuronal activity is lowered substantially by reducing image contrast. We then applied the same adaptation paradigm, but this time we lowered the fMRI signal by changing object shape. While the overall fMRI signal in category-related regions such as the face-related pFs was drastically reduced for non-face stimuli, the adaptation level obtained for these stimuli remained high. We hypothesize that the relatively greater adaptation level following exposure to "nonoptimal" object shapes is indicative of small subsets of neurons responding vigorously to these "nonoptimal" objects even when the overall fMRI activity is low. CONCLUSIONS: Our results show that fMR-adaptation can be used to differentiate between neuronal activation patterns that appear similar in the overall fMRI signal. The results suggest that it may be possible to employ fMR-adaptation to reveal functionally heterogeneous islands of activity, which are too small to image using conventional imaging methods.

Adult↗
PubMed1989

Nuclear magnetic resonance study of free and bound water fractions in normal lenses.

Proton NMR relaxation times T1 and T2 were determined for normal lenses excised from sexually mature animals from seven different species. Lenses were immersed in physiological buffer during measurements, and suppression methods were employed to null the buffer signal. This enabled selective analysis of lenticular water. Observed relaxation times were correlated with protein and water content. At 37 degrees C and 1.89 Tesla, single-exponential spin-lattice relaxation was observed, but spin-spin relaxation was found to be double-exponential. It was shown that the short-T2 fraction is proportional to protein concentration; this fraction was attributed to water bound to protein. The long-T2 fraction was attributed to free lenticular water. The amounts of free and bound water thus obtained were used in the spin-lattice relaxation rate equation for rapid exchange in a two-component system to calculate the magnitudes of the two corresponding T1 relaxation components.

Animals↗