Lactate cross-feeding between Bifidobacterium species and Megasphaera indica contributes to butyrate formation in the human colonic environment.

Butyrate, a physiologically active molecule, can be synthesized through metabolic interactions among colonic microorganisms. Previously, in a fermenting trial of human fecal microbiota, we observed that the butyrogenic effect positively correlated with the increasing Bifidobacterium population and an unidentified Megasphaera species. Therefore, we hypothesized that a cross-feeding phenomenon exists between Bifidobacterium and Megasphaera, where Megasphaera is the butyrate producer, and its growth relies on the metabolites generated by Bifidobacterium. To validate this hypothesis, three bacterial species (B. longum, B. pseudocatenulatum, and M. indica) were isolated from fecal cultures fermenting hydrolyzed xylan; pairwise cocultures were conducted between the Bifidobacterium and M. indica isolates; the microbial interactions were determined based on bacterial genome information, cell growth, substrate consumption, metabolite quantification, and metatranscriptomics. The results indicated that two Bifidobacterium isolates contained distinct gene clusters for xylan utilization and expressed varying substrate preferences. In contrast, M. indica alone scarcely grew on the xylose-based substrates. The growth of M. indica was significantly elevated by coculturing it with bifidobacteria, while the two Bifidobacterium species responded differently in the kinetics of cell growth and substrate consumption. Coculturing led to the depletion of lactate and increased the formation of butyrate. An RNA-seq analysis further revealed the upregulation of M. indica genes involved in the lactate utilization and butyrate formation pathways. We concluded that lactate generated by Bifidobacterium through catabolizing xylose fueled the growth of M. indica and triggered the synthesis of butyrate. Our findings demonstrated a novel cross-feeding mechanism to generate butyrate in the human colon.IMPORTANCEButyrate is an important short-chain fatty acid that is produced in the human colon through microbial fermentation. Although many butyrate-producing bacteria exhibit a limited capacity to degrade nondigestible food materials, butyrate can be formed through cross-feeding microbial metabolites, such as acetate or lactate. Previously, the literature has explicated the butyrate-forming links between Bifidobacterium and Faecalibacterium prausnitzii and between Bifidobacterium and Eubacterium rectale. In this study, we provided an alternative butyrate synthetic pathway through the interaction between Bifidobacterium and Megasphaera indica. M. indica is a species named in 2014 and is indigenous to the human intestinal tract. Scientific studies explaining the function of M. indica in the human colon are still limited. Our results show that M. indica proliferated based on the lactate generated by bifidobacteria and produced butyrate as its end metabolic product. The pathways identified here may contribute to understanding butyrate formation in the gut microbiota.

Novel Low-Power Construction of Chaotic S-Box in Multilayer Perceptron.

Multilayer perceptron is composed of massive distributed neural processors interconnected. The nonlinear dynamic components in these processors expand the input data into a linear combination of synapses. However, the nonlinear mapping ability of original multilayer perceptron is limited when processing high complexity information. The introduction of more powerful nonlinear components (e.g., S-box) to multilayer perceptron can not only reinforce its information processing ability, but also enhance the overall security. Therefore, we combine the methods of cryptography and information theory to design a low-power chaotic S-box (LPC S-box) with entropy coding in the hidden layer to make the multilayer perceptron process information more efficiently and safely. In the performance test, our S-box architecture has good properties, which can effectively resist main known attacks (e.g., Berlekamp Massey-attack and Ronjom-Helleseth attack). This interdisciplinary work can attract more attention from academia and industry to the security of multilayer perceptron.

Temporal event searches based on event maps and relationships.

To satisfy a user's need to find and understand the whole picture of an event effectively and efficiently, in this paper we formalize the problem of temporal event searches and propose a framework of event relationship analysis for search events based on user queries. We define three kinds of event relationships: temporal, content dependence, and event reference, that can be used to identify to what extent a component event is dependent on another in the evolution of a target event (i.e., the query event). The search results are organized as a temporal event map (TEM) that serves as the whole picture about an event's evolution or development by showing the dependence relationships among events. Based on the event relationships in the TEM, we further propose a method to measure the degrees of importance of events, so as to discover the important component events for a query, as well as the several algebraic operators involved in the TEM, that allow users to view the target event. Experiments conducted on a real data set show that our method outperforms the baseline method Event Evolution Graph (EEG), and it can help discover certain new relationships missed by previous methods and even by human annotators.

Anchor Link Prediction across Attributed Networks via Network Embedding.

Presently, many users are involved in multiple social networks. Identifying the same user in different networks, also known as anchor link prediction, becomes an important problem, which can serve numerous applications, e.g., cross-network recommendation, user profiling, etc. Previous studies mainly use hand-crafted structure features, which, if not carefully designed, may fail to reflect the intrinsic structure regularities. Moreover, most of the methods neglect the attribute information of social networks. In this paper, we propose a novel semi-supervised network-embedding model to address the problem. In the model, each node of the multiple networks is represented by a vector for anchor link prediction, which is learnt with awareness of observed anchor links as semi-supervised information, and topology structure and attributes as input. Experimental results on the real-world data sets demonstrate the superiority of the proposed model compared to state-of-the-art techniques.

Nearly Pure Red Color Upconversion Luminescence of Ln-Doped Sc2O3 with Unexpected RE-MOFs Molecular Alloys as Precursor.

Unexpected Sc/Ln codoped rare earth metal-organic frameworks (RE-MOFs) molecular alloys (MAs) based on an oxalic acid ligands were obtained. Calcination of the RE-MOFs MAs gave the corresponding codoped rare earth oxides a strong and nearly pure red color upconversion luminescence. It allows the resulting lanthanide ion (Ln3+) doped upconversion materials a wide range of applications from optical communications to disease diagnosis. Moreover, the pyrolysis RE-MOFs MAs precursor has demonstrated to be an effective preparation method for a uniform Ln-doped Sc2O3 system.

Roughness-controlled self-assembly of mannitol/LB agar microparticles by polymorphic transformation for pulmonary drug delivery.

Novel roughness-controlled mannitol/LB Agar microparticles were synthesized by polymorphic transformation and self-assembly method using hexane as the polymorphic transformation reagent and spray-dried mannitol/LB Agar microparticles as the starting material. As-prepared microparticles were characterized by Fourier transform infrared spectra (FTIR), X-ray diffraction spectra (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), and Andersen Cascade Impactor (ACI). The XRD and DSC results indicate that after immersing spray-dried mannitol/LB Agar microparticles in hexane, ß-mannitol was completely transformed to α-mannitol in 1 h, and all the δ-mannitol was transformed to α form after 14 days. SEM shows that during the transformation the nanobelts on the spray-dried mannitol/LB Agar microparticles become more dispersed and the contour of the individual nanobelts becomes more noticeable. Afterward, the nanobelts self-assemble to nanorods and result in rod-covered mannitol/LB Agar microparticles. FTIR indicates new hydrogen bonds were formed among mannitol, LB Agar, and hexane. SEM images coupled with image analysis software reveal that different surface morphology of the microparticles have different drug adhesion mechanisms. Comparison of ACI results and image analysis of SEM images shows that an increase in the particle surface roughness can increase the fine particle fractions (FPFs) using the rod-covered mannitol microparticles as drug carriers. Transformed microparticles show higher FPFs than commercially available lactose carriers. An FPF of 28.6 ± 2.4% was achieved by microparticles transformed from spray-dried microparticles using 2% mannitol(w/v)/LB Agar as feed solution. It is comparable to the highest FPF reported in the literature using lactose and spray-dried mannitol as carriers.

Influence of chain length on the colonic fermentation of xylooligosaccharides.

Xylooligosaccharides (XOS) have been employed as prebiotics containing oligomers of varying sizes or molecular ratios. XOS with a low degree of polymerization (DP) has been demonstrated to have high prebiotic potential. However, there is limited information regarding the specific chain length of XOS required to elicit distinct responses in the gut microbiota. In this study, we aimed to explore whether variations in XOS DP could alter the fate of colonic fermentation. Five XOS fractions (BWXFs) with DP ranges of >40, 20-40, 10-20, 5-10, and 2-4 were prepared by beechwood xylan autohydrolysis and tested on human gut microbiota. Extracellular XOS degradation was observed for molecules with a DP exceeding 5. BWXF treatments altered the microbial community structures, and substrate size-dependent effects on the microbial composition and metabolic outputs were observed. Bacteroidaceae were specifically enriched by xylan. Lachnospiraceae were particularly stimulated by XOS with a DP of 20-40 and 2-4. Bifidobacteriaceae were notably enriched by XOS with a DP of 5-20. High butyrate yields were obtained from cultures containing long-chain BWXFs. Microbiota responses differed with XOS DP composition changes, and microbial competition with XOS with a DP of 2-4 requires further exploration.

The Effect of Diet Composition on the Post-operative Outcomes of Roux-en-Y Gastric Bypass in Mice.

PURPOSE: Roux-en-Y gastric bypass (RYGB) leads to the improvement of many obesity-associated conditions. The degree to which post-operative macronutrient composition contributes to metabolic improvement after RYGB is understudied. METHODS: A mouse model of RYGB was used to examine the effects of diet on the post-operative outcomes of RYGB. Obese mice underwent either Sham or RYGB surgery and were administered either chow or HFD and then monitored for an additional 8 weeks. RESULTS: After RYGB, reductions to body weight, fat mass, and lean mass were similar regardless of diet. RYGB and HFD were independently detrimental to bone mineral density and plasma vitamin D levels. Independent of surgery, HFD accelerated hematopoietic stem and progenitor cell proliferation and differentiation and exhibited greater myeloid lineage commitment. Independent of diet, systemic iron deficiency was present after RYGB. In both Sham and RYGB groups, HFD increased energy expenditure. RYGB increased fecal energy loss, and HFD after RYGB increased fecal lipid content. RYGB lowered fasting glucose and liver glycogen levels but HFD had an opposing effect. Indices of insulin sensitivity improved independent of diet. HFD impaired improvements to dyslipidemia, NAFLD, and fibrosis. CONCLUSION: Post-operative diet plays a significant role in determining the degree to which RYGB reverses obesity-induced metabolic abnormalities such as hyperglycemia, dyslipidemia, and NAFLD. Diet composition may be targeted in order to assist in the treatment of post-RYGB bone mineral density loss and vitamin D deficiency as well as to reverse myeloid lineage commitment. HFD after RYGB continues to pose a significant multidimensional health risk.

Hydrodynamics and mass transfer of concentric-tube internal loop airlift reactors: A review.

The concentric-tube internal loop airlift reactor is a typical reactor configuration which has been adopted for a myriad of chemical and biological processes. The reactor hydrodynamics (including mixing) and the mass transfer between the gas and liquid phases remarkably affect the operational conditions and thus are crucial to the overall reactor performance. Hence, this study aims at providing a thorough description of the basic concepts and a comprehensive review of the relevant reported studies on the hydrodynamics and mass transfer of the concentric-tube internal loop airlift reactors, taking microalgae cultivation as an exemplary application. In particular, the reactor characteristics, geometry, CFD modeling, experimental characterization, and scale up considerations are elucidated. The research gaps for future research and development are also identified.

Reversal of NAFLD After VSG Is Independent of Weight-Loss but RYGB Offers More Efficacy When Maintained on a High-Fat Diet.

PURPOSE: Bariatric surgery is emerging as an effective treatment for obesity and the metabolic syndrome. Recently, we demonstrated that Roux-en-Y gastric bypass (RYGB), but not vertical sleeve gastrectomy (VSG), resulted in improvements to white adipose physiology and enhanced brown adipose functioning. Since beneficial alterations to liver health are also expected after bariatric surgery, comparing the post-operative effects of RYGB and VSG on liver physiology is essential to their application in the treatment of non-alcoholic fatty liver disease (NAFLD). MATERIALS AND METHODS: The effects of RYGB and VSG on liver physiology were compared using diet induced mouse model of obesity. High-fat diet (HFD) was administered for 12 weeks after surgery and alterations to liver physiology were assessed. RESULTS: Both RYGB and VSG showed decreased liver weight as well as reductions to hepatic cholesterol and triglyceride levels. There were demonstrable improvements to NAFLD activity score (NAS) and fibrosis stage scoring after both surgeries. In RYGB, these beneficial changes to liver function resulted from the downregulation of pro-fibrotic and upregulation anti-fibrotic genes, as well as increased fatty acid oxidation and bile acid flux. For VSG, though similar alterations were observed, they were less potent. However, VSG did significantly downregulate pro-fibrotic genes and showed increased glycogen content paralleled by decreased glycogenolysis which may have contributed to the resolution of NAFLD. CONCLUSION: RYGB and VSG improve liver physiology and function, but RYGB is more efficacious. Resolutions of NAFLD in RYGB and VSG are achieved through different processes, independent of weight loss.

Microsomal triglyceride transfer protein regulates intracellular lipolysis in adipocytes independent of its lipid transfer activity.

BACKGROUND: The triglyceride (TG) transfer activity of microsomal triglyceride transfer protein (MTP) is essential for lipoprotein assembly in the liver and intestine; however, its function in adipose tissue, which does not assemble lipoproteins, is unknown. Here we have elucidated the function of MTP in adipocytes. APPROACH AND RESULTS: We demonstrated that MTP is present on lipid droplets in human adipocytes. Adipose-specific MTP deficient (A-Mttp-/-) male and female mice fed an obesogenic diet gained less weight than Mttpf/f mice, had less fat mass, smaller adipocytes and were insulin sensitive. A-Mttp-/- mice showed higher energy expenditure than Mttpf/f mice. During a cold challenge, A-Mttp-/- mice maintained higher body temperature by mobilizing more fatty acids. Biochemical studies indicated that MTP deficiency de-repressed adipose triglyceride lipase (ATGL) activity and increased TG lipolysis. Both wild type MTP and mutant MTP deficient in TG transfer activity interacted with and inhibited ATGL activity. Thus, the TG transfer activity of MTP is not required for ATGL inhibition. C-terminally truncated ATGL that retains its lipase activity interacted less efficiently than full-length ATGL. CONCLUSION: Our findings demonstrate that adipose-specific MTP deficiency increases ATGL-mediated TG lipolysis and enhances energy expenditure, thereby resisting diet-induced obesity. We speculate that the regulatory function of MTP involving protein-protein interactions might have evolved before the acquisition of TG transfer activity in vertebrates. Adipose-specific inhibition of MTP-ATGL interactions may ameliorate obesity while avoiding the adverse effects associated with inhibition of the lipid transfer activity of MTP.

Recomposition and storage of sunlight with intelligent phosphors for enhanced photosynthesis.

This work presents a smart solar energy regulation strategy using photon tunable long persistent phosphors as solar energy harvesting antennas to enhance overall sunlight utilization by photosynthetic organisms in multiple modes.

RYGB Is More Effective than VSG at Protecting Mice from Prolonged High-Fat Diet Exposure: An Occasion to Roll Up Our Sleeves?

PURPOSE: Understanding the effects of Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG) on adipose tissue physiology is important for the treatment of obesity-related metabolic disorders. By using robust mouse models of bariatric surgery that closely resemble those performed in humans, we can compare the effects of RYGB and VSG on adipose physiology in the absence of post-operative confounds such as diet and lifestyle changes. MATERIALS AND METHODS: RYGB and VSG were compared using a diet-induced mouse model of obesity. High-fat diet (HFD) was administered post-operatively and changes to white and brown adipose tissue were evaluated, along with alterations to weight, glucose homeostasis, dyslipidemia, and insulin sensitivity. RESULTS: After prolonged exposure to high-fat diet post-operatively, RYGB was effective in achieving sustained weight loss, while VSG unexpectedly accelerated weight gain rates. The resolution of obesity-related comorbidities such as glucose and insulin intolerance, dyslipidemia, and insulin sensitivity was improved after RYGB, but not for VSG. In RYGB, there were improvements to the function and health of white adipose tissue, enhanced brown adipose metabolism, and the browning of subcutaneous white adipose tissue, with no comparable changes seen for these factors after VSG. Some markers of systemic inflammation improved after both RYGB and VSG. CONCLUSION: There are significantly different effects between RYGB and VSG when HFD is administered post-operatively and robust mouse models of bariatric surgery are used. RYGB resulted in lasting physiological and metabolic changes but VSG showed little difference from that of its sham-operated, DIO counterpart.

Enhanced Biophotocurrent Generation in Living Photosynthetic Optical Resonator.

Bioenergy from photosynthetic living organisms is a potential solution for energy-harvesting and bioelectricity-generation issues. With the emerging interest in biophotovoltaics, extracting electricity from photosynthetic organisms remains challenging because of the low electron-transition rate and photon collection efficiency due to membrane shielding. In this study, the concept of "photosynthetic resonator" to amplify biological nanoelectricity through the confinement of living microalgae (Chlorella sp.) in an optical micro/nanocavity is demonstrated. Strong energy coupling between the Fabry-Perot cavity mode and photosynthetic resonance offers the potential of exploiting optical resonators to amplify photocurrent generation as well as energy harvesting. Biomimetic models and living photosynthesis are explored in which the power is increased by almost 600% and 200%, respectively. Systematic studies of photosystem fluorescence and photocurrent are simultaneously carried out. Finally, an optofluidic-based photosynthetic device is developed. It is envisaged that the key innovations proposed in this study can provide comprehensive insights in biological-energy sciences, suggesting a new avenue to amplify electrochemical signals using an optical cavity. Promising applications include photocatalysis, photoelectrochemistry, biofuel devices, and sustainable optoelectronics.

Effect of particle shape on dry particle inhalation: study of flowability, aerosolization, and deposition properties.

The shape effects of dry particles on flowability, aerosolization, and deposition properties in inhalation drug delivery are studied. The properties are compared with similar size range particles of different shapes such as sphere, needle, cube, plate, and pollen. Flowability of the particles is characterized by Carr's compressibility index and angle of slide (theta) method. The aerosolization and deposition properties of the particles are studied in vitro using an eight-stage Anderson cascade impactor with a Rotahaler. Pollen-shaped particles are found to exhibit better flowability, higher emitted dose, and higher fine particle fraction than particles of other shapes in similar size range. They showed minimum theta of 35 degrees and maximum emitted dose of 87% and fine particle fraction of 16%. The use of pollen-shaped particles can be a potential improvement in dry particle inhalation.

Surgical Mouse Models of Vertical Sleeve Gastrectomy and Roux-en Y Gastric Bypass: a Review.

Reviewed here are multiple mouse models of vertical sleeve gastrectomy (VSG) and Roux-en Y gastric bypass (RYGB) that have emerged over the past decade. These models use diverse approaches to both operative and perioperative procedures. Scrutinizing the benefits and pitfalls of each surgical model and what to expect in terms of post-operative outcomes will enhance our assessment of studies using mouse models, as well as advance our understanding of their translational potential. Two mouse models of bariatric surgery, VSG-lembert and RYGB-small pouch, demonstrate low mortality and most closely recapitulate the human forms of surgery. The use of liquid diets can be minimized, and in mice, RYGB demonstrates more reliable and longer lasting effects on weight loss compared to that of VSG.

On the Effectiveness of Least Squares Generative Adversarial Networks.

Unsupervised learning with generative adversarial networks (GANs) has proven to be hugely successful. Regular GANs hypothesize the discriminator as a classifier with the sigmoid cross entropy loss function. However, we found that this loss function may lead to the vanishing gradients problem during the learning process. To overcome such a problem, we propose in this paper the Least Squares Generative Adversarial Networks (LSGANs) which adopt the least squares loss for both the discriminator and the generator. We show that minimizing the objective function of LSGAN yields minimizing the Pearson χ2 divergence. We also show that the derived objective function that yields minimizing the Pearson χ2 divergence performs better than the classical one of using least squares for classification. There are two benefits of LSGANs over regular GANs. First, LSGANs are able to generate higher quality images than regular GANs. Second, LSGANs perform more stably during the learning process. For evaluating the image quality, we conduct both qualitative and quantitative experiments, and the experimental results show that LSGANs can generate higher quality images than regular GANs. Furthermore, we evaluate the stability of LSGANs in two groups. One is to compare between LSGANs and regular GANs without gradient penalty. We conduct three experiments, including Gaussian mixture distribution, difficult architectures, and a newly proposed method - datasets with small variability, to illustrate the stability of LSGANs. The other one is to compare between LSGANs with gradient penalty (LSGANs-GP) and WGANs with gradient penalty (WGANs-GP). The experimental results show that LSGANs-GP succeed in training for all the difficult architectures used in WGANs-GP, including 101-layer ResNet.