Effect of total dissolved gas supersaturation on the survival of common carp (Cyprinus carpio) and silver carp (Hypophthalmichthys molitrix).

Flood discharge results in total dissolved gas (TDG) supersaturation downstream of a dam during the flood period. Fish suffer death from gas bubble disease (GBD) caused by TDG supersaturation. Nonetheless, current studies mainly attach importance to the survival of benthic fish affected by TDG supersaturation in the Yangtze River in China. Few studies have attempted to investigate the survival of pelagic fish influenced by TDG supersaturated water and compare the tolerance characteristics to TDG supersaturation between benthic and pelagic fish. To identify the survival of fish species that inhabit the various water layers affected by TDG supersaturation, silver carp (Hypophthalmichthys molitrix) (pelagic fish) and common carp (Cyprinus carpio) (benthic fish) were chosen to conduct an acute exposure experiment of four different TDG supersaturation levels (125%, 130%, 135% and 140%). The findings illustrated that the two fish species both exhibited evident aberrant behaviours of maladjustment in TDG supersaturated water. Obvious GBD symptoms were also found in the test fish. The survival probability of silver carp and common carp decreased with increasing levels of TDG supersaturation. The median survival time (ST50 ) values of the silver carp exposed to four levels of TDG supersaturated water (125%, 130%, 135% and 140%) were 26.84, 7.96, 5.56 and 3.62 h, respectively, whereas the ST50 values of common carp were 53.50, 26.00, 16.50 and 11.70 h, respectively. When compared with common carp, silver carp had a weaker tolerance to TDG-supersaturated water and were vulnerable to GBD. It shows that levels above 125% are not safe for common carp survival. In terms of the tolerance threshold value, silver carp merits further investigation because it showed lower tolerance to TDG than did common carp.

Correction to: Detecting focal cortical dysplasia lesions from FLAIR-negative images based on cortical thickness.

It was highlighted that the original article [1] contained an error in the Quantitative evaluation of Methods. A bracket was misplaced in the formula. This Correction article shows the incorrect and correct formula.

Detecting focal cortical dysplasia lesions from FLAIR-negative images based on cortical thickness.

BACKGROUND: Focal cortical dysplasia (FCD) is a neuronal migration disorder and is a major cause of drug-resistant epilepsy. However, many focal abnormalities remain undetected during routine visual inspection, and many patients with histologically confirmed FCD have normal fluid-attenuated inversion recovery (FLAIR-negative) images. The aim of this study was to quantitatively evaluate the changes in cortical thickness with magnetic resonance (MR) imaging of patients to identify FCD lesions from FLAIR-negative images. METHODS: We first used the three-dimensional (3D) Laplace method to calculate the cortical thickness for individuals and obtained the cortical thickness mean image and cortical thickness standard deviation (SD) image based on all 32 healthy controls. Then, a cortical thickness extension map was computed by subtracting the cortical thickness mean image from the cortical thickness image of each patient and dividing the result by the cortical thickness SD image. Finally, clusters of voxels larger than three were defined as the FCD lesion area from the cortical thickness extension map. RESULTS: The results showed that three of the four lesions that occurred in non-temporal areas were detected in three patients, but the detection failed in three patients with lesions that occurred in the temporal area. The quantitative analysis of the detected lesions in voxel-wise on images revealed the following: specificity (99.78%), accuracy (99.76%), recall (67.45%), precision (20.42%), Dice coefficient (30.01%), Youden index (67.23%) and area under the curve (AUC) (83.62%). CONCLUSION: Our studies demonstrate an effective method to localize lesions in non-temporal lobe regions. This novel method automatically detected FCD lesions using only FLAIR-negative images from patients and was based only on cortical thickness feature. The method is noninvasive and more effective than a visual analysis for helping doctors make a diagnosis.

Automatic localization and segmentation of focal cortical dysplasia in FLAIR-negative patients using a convolutional neural network.

PURPOSE: Focal cortical dysplasia (FCD) is a common cause of epilepsy; the only treatment is surgery. Therefore, detecting FCD using noninvasive imaging technology can help doctors determine whether surgical intervention is required. Since FCD lesions are small and not obvious, diagnosing FCD through visual evaluations of magnetic resonance imaging (MRI) scans is difficult. The purpose of this study is to detect and segment histologically confirmed FCD lesions in images of normal fluid-attenuated inversion recovery (FLAIR)-negative lesions using convolutional neural network (CNN) technology. METHODS: The technique involves training a six-layer CNN named Net-Pos, which consists of two convolutional layers (CLs); two pooling layers (PLs); and two fully connected (FC) layers, including 60 943 learning parameters. We employed activation maximization (AM) to optimize a series of pattern image blocks (PIBs) that were most similar to a lesion image block by using the trained Net-Pos. We developed an AM and convolutional localization (AMCL) algorithm that employs the mean PIBs combined with convolution to locate and segment FCD lesions in FLAIR-negative patients. Five evaluation indices, namely, recall, specificity, accuracy, precision, and the Dice coefficient, were applied to evaluate the localization and segmentation performance of the algorithm. RESULTS: The PIBs most similar to an FCD lesion image block were identified by the trained Net-Pos as image blocks with brighter central areas and darker surrounding image blocks. The technique was evaluated using 18 FLAIR-negative lesion images from 12 patients. The subject-wise recall of the AMCL algorithm was 83.33% (15/18). The Dice coefficient for the segmentation performance was 52.68. CONCLUSION: We developed a novel algorithm referred to as the AMCL algorithm with mean PIBs to effectively and automatically detect and segment FLAIR-negative FCD lesions. This work is the first study to apply a CNN-based model to detect and segment FCD lesions in images of FLAIR-negative lesions.

Revealing the influence of microbiota on the quality of Pu-erh tea during fermentation process by shotgun metagenomic and metabolomic analysis.

Multispecies microbial community in natural solid-state fermentation (SSF) is crucial for the formation of Chinese Pu-erh tea's unique quality. However, the association between microbiota and tea quality are still poorly understood. Herein, shotgun metagenomic and metabolomic analysis showed that significant variations in composition of microbiota, collective functional genes, and flavour compounds occurred during SSF process. Furthermore, the formation pathways of the dominant flavours including theabrownin, methoxy-phenolic compound, alcohol and carvone were proposed. Moreover, biological interaction networks analysis among functional core microbiota, functional genes, and dominant flavours indicated Aspergillus was the main flavour-producing microorganism in the early SSF, while many other genera including Bacillus, Rasamsonia, Lichtheimia, Debaryomyces were determined as the functional core microorganism for flavours production in the late SSF. This study provides a perspective for bridging the gap between the microbiota and quality in Pu-erh tea, and benefited for further optimizing production efficiency and product quality.

Methylglyoxal: A newly detected and potentially harmful metabolite in the blood of ketotic dairy cows.

Ketosis causes serious economic losses for the modern dairy industry because it is a highly prevalent metabolic disease among cows in high-producing herds during the transition period. Due to some striking similarities between diabetes in humans and ketosis in dairy cows, there is potential for the use of methylglyoxal (MGO)-commonly used in human diabetics-as a biomarker in dairy cattle. However, currently no data are available about the presence of MGO in the serum of dairy cattle or about the characteristics of its production or its potential contribution in the pathogenesis of ketosis. To determine the potential origin and pathway of formation of MGO, cows in different metabolic conditions [i.e., non-subclinically ketotic dairy cows in early lactation (n = 7), subclinically ketotic dairy cows in early lactation (n = 8), overconditioned dry cows (BCS >4.25, n = 6), and nonlactating heifers (n = 6)] were selected. Serum MGO concentrations were determined and correlated with indicators of the glucose and lipid metabolism and with haptoglobin (Hp) as an inflammatory marker. The serum MGO concentrations in subclinically ketotic cows (712.60 ± 278.77 nmol/L) were significantly greater than in nonlactating heifers (113.35 ± 38.90 nmol/L), overconditioned dry cows (259.71 ± 117.97 nmol/L), and non-subclinically ketotic cows (347.83 ± 63.56 nmol/L). In serum of lactating cows, concentrations of glucose and fructosamine were lower than in heifers and were negatively correlated with MGO concentrations. Even so, concentrations of metabolic and inflammatory markers such as dihydroxyacetone phosphate, nonesterified fatty acids, ß-hydroxybutyrate, acetone, and Hp were remarkably higher in subclinically ketotic cows compared with nonlactating heifers; these metabolites were also positively correlated with MGO. In human diabetics elevated MGO concentrations are stated to originate from both hyperglycemia and the enhanced lipid metabolism, whereas higher MGO concentrations in subclinically ketotic cows were not associated with hyperglycemia. Therefore, our data suggest MGO in dairy cows to be a metabolite produced from the metabolization of acetone within the lipid metabolization pathway and from the metabolization of dihydroxyacetone phosphate. Furthermore, the highly positive correlation between MGO and Hp suggests that this reactive compound might be involved in the proinflammatory state of subclinical ketosis in dairy cows. However, more research is needed to determine the potential use of MGO as a biomarker for metabolic failure in dairy cows.

Super-resolution acquisition and reconstruction for cone-beam SPECT with low-resolution detector.

BACKGROUND AND OBJECTIVE: Single-photon emission computed tomography (SPECT) imaging, which provides information that reflects the human body's metabolic processes, has unique application value in disease diagnosis and efficacy evaluation. The imaging resolution of SPECT can be improved by exploiting high-performance detector hardware, but this exploitation generates high research and development costs. In addition, the inherent hardware structure of SPECT requires the use of a collimator, which limits the resolution in SPECT. The objective of this study is to propose a novel super-resolution (SR) reconstruction algorithm with two acquisition methods for cone-beam SPECT with low-resolution (LR) detector. METHODS: A SR algorithm with two acquisition methods is proposed for cone-beam SPECT imaging in the projection domain. At each sampling angle, multi LR projections can be obtained by regularly moving the LR detector. For the two proposed acquisition methods, we develop a new SR reconstruction algorithm. Using our SR algorithm, a SR projection with the corresponding sampling angle can be obtained from multi LR projections via multi-iterations, and then, the SR SPECT image can be reconstructed. The peak signal-to-noise ratio (PSNR), structural similarity index measure (SSIM), signal-to-noise ratio (SNR) and contrast recovery coefficient (CRC) are used to evaluate the final reconstruction quality. RESULTS: The simulation results obtained under clean and noisy conditions verify the effectiveness of our SR algorithm. Three different phantoms are verified separately. 16 LR projections are obtained at each sampling angle, each with 32 × 32 bins. The high-resolution (HR) projection has 128 × 128 bins. The reconstruction result of the SR algorithm obtains an evaluation value that is almost the same as that of the HR reconstruction result. Our results indicate that the resolution of the resulting SPECT image is almost four times higher. CONCLUSIONS: The authors develop a SR reconstruction algorithm with two acquisition methods for the cone-beam SPECT system. The simulation results obtained in clean and noisy environments prove that the SR algorithm has potential value, but it needs to be further tested on real equipment.

Improved detection of focal cortical dysplasia in normal-appearing FLAIR images using a Bayesian classifier.

PURPOSE: Focal cortical dysplasia (FCD) is a malformation of cortical development that often causes pharmacologically intractable epilepsy. However, FCD lesions are frequently characterized by minor structural abnormalities that can easily go unrecognized, making diagnosis difficult. Therefore, many epileptic patients have had pathologically confirmed FCD lesions that appeared normal in pre-surgical fluid-attenuated inversion recovery (FLAIR) magnetic resonance (MR) studies. Such lesions are called "FLAIR-negative." This study aimed to improve the detection of histopathologically verified FCD in a sample of patients without visually appreciable lesions. METHODS: The technique first extracts a series of features from a FLAIR image. Then, three naive Bayesian classifiers with probability (NBCP) are trained based on different numbers of feature maps to classify voxels as lesional or healthy voxels and assign the lesions a probability of correct classification. This method classifies the three-dimensional (3D) images of all patients using leave-one-out cross-validation (LOOCV). Finally, the 3D lesion probability map, including epileptogenic lesions, is obtained by removing false-positive voxel outliers using the morphological method. The performance of the NBCP was assessed for quantitative analysis by specificity, accuracy, recall, precision, and Dice coefficient in subject-wise, lesion-wise, and voxel-wise manners. RESULTS: The best detection results were obtained by using four features: cortical thickness, symmetry, K-means, and modified texture energy. There were eight lesions in seven patients. The subject-wise sensitivity of the proposed method was 85.71% (6/7). Seven out of eight lesions were detected, so the lesion-wise sensitivity was 87.50% (7/8). No significant differences in effectiveness were found between automated lesion detection using four features and lesion detection using manual segmentation, as voxels were quantitatively analyzed in terms of specificity (mean ± SD = 99.64 ± 0.13), accuracy (mean ± SD = 99.62 ± 0.14), recall (mean ± SD = 73.27 ± 26.11), precision (mean ± SD = 11.93 ± 8.16), and Dice coefficient (mean ± SD = 22.82 ± 15.57). CONCLUSION: We developed a novel automatic voxel-based method to improve the detection of FCD FLAIR-negative lesions. To the best of our knowledge, this study is the first to detect FCD lesions that appear normal in pre-surgical 3D high-resolution FLAIR images alone with a limited number of radiomics features. We optimized the algorithm and selected the best prior probability to improve the detection. For non-temporal lobe epilepsy (non-TLE) patients, lesions could be accurately located, although there were still false-positive areas.

Effect of Total Dissolved Gas Supersaturation on the Survival of Bighead Carp (Hypophthalmichthys Nobilis).

To assess the effect of TDG on the survival of different sizes of pelagic fish, bighead carp (Hypophthalmichthys nobilis) were subjected to TDG supersaturated water at levels of 125, 130, 135, and 140%. The results showed that apparent abnormal behaviours and symptoms of gas bubble disease (GBD) were observed in bighead carp. The survival probability of large and small juvenile bighead carp declined with increasing TDG levels. The median survival time (ST50) values of large juvenile bighead carp were 74.97 and 31.90 h at 130% and 140% TDG, respectively. While the ST50 of small fish were 22.40 and 6.72 h at the same TDG levels. In comparison to the large juvenile bighead carp, the small juvenile bighead carp showed weaker tolerance to TDG supersaturated water. Furthermore, acute lethality experiments after chronic exposure to TDG were initiated to further investigate the effect of TDG on bighead carp. The juveniles were first subjected to 115% TDG supersaturated water for 96 h. After chronic exposure, live fish were immediately transferred to TDG supersaturated water at levels of 125, 130, 135, and 140%. The results demonstrated that no fish died under chronic exposure and few fish exhibited slight GBD symptoms. The ST50 values for bighead carp subjected to acute exposure after chronic exposure were 61.23 and 23.50 h at 130 and 140%, respectively. Compared with the bighead carp subjected to acute exposure, bighead carp subjected to multiple exposures were more vulnerable to TDG.

Lethal Effect of Total Dissolved Gas-Supersaturated Water with Suspended Sediment on River Sturgeon (Acipenser dabryanus).

High total dissolved gas (TDG) levels and excessive suspended sediment (SS) concentrations pose serious threats to fish survival during flood season. However, little information is available on the effects of TDG supersaturation with varying SS concentrations on fish. In this study, laboratory experiments were performed to investigate the effects of TDG supersaturation with varying SS concentrations on five-month-old river sturgeons (Acipenser dabryanus). The test fish were exposed to combinations of SS concentrations (0, 200, 600 and 1,000 mg/L) and TDG levels (125, 130, 135 and 140%), and their mortality and median lethal time (LT50) were quantified. The fish showed abnormal behaviors (e.g., quick breathing, fast swimming and an agitated escape response) and symptoms of gas bubble disease (GBD). SS increased the mortality of river sturgeon exposed to TDG supersaturation. Furthermore, the LT50 values at 125% TDG were 4.47, 3.11, 3.07 and 2.68 h for the different SS concentrations (0, 200, 600 and 1,000 mg/L, respectively), representing a significant decrease in LT50 with increasing SS. However, at higher TDG levels (130-140%), there was no significant increase in LT50 with increasing SS. Therefore, river sturgeon showed weak tolerance of TDG-supersaturated water with SS.

Inhibition of Methylglyoxal-Induced Histone H1 Nε-Carboxymethyllysine Formation by (+)-Catechin.

Reactive dicarbonyl species (RCS) such as methylglyoxal (MGO) and glyoxal (GO) are common intermediates in protein damage, leading to the formation of advanced glycation end products (AGEs) through nonenzymatic glycation. (+)-Catechin, a natural plant extract from tea, has been evaluated for its ability in trapping GO and MGO. However, (+)-catechin is also reported to have both antioxidant ability and pro-oxidant properties. Until now, whether (+)-catechin can inhibit the formation of nonenzymatic glycation and the mechanism of the inhibition in nucleoprotein nonenzymatic glycation is still unclear. In the present study, histone H1 and MGO were used to establish an in vitro (100 mM phosphate buffer solution (PBS), pH 7.4, 37 °C) protein glycation model to study the trapping ability of (+)-catechin. Our data show that MGO caused dose-dependent protein damage, and the content of MGO-induced Schiff base formation was inhibited by (+)-catechin when the molecular ratio of catechin:MGO was 1:6. The formation of Nε-carboxymethyllysine (CML) was reduced significantly when the ratio of (+)-catechin and MGO was 1:1, which was similar to the inhibition effect of aminoguanidine (AG). The formation of CML under in vitro conditions can be inhibited by low concentration (12.5-100 µM) of (+)-catechin but not with high concentration (200-800 µM) of (+)-catechin. The reason is that the high concentration of (+)-catechin did not inhibit CML formations due to H2O2 produced by (+)-catechin. In the presence of catalase, catechin can inhibit MGO-induced CML formation. In conclusion, the trapping ability of (+)-catechin may be more effective at the early stage of nonenzymatic glycation. However, a high concentration (200-800 µM) of (+)-catechin may not inhibit the formation of CML because it induced the increase of H2O2 formation.