Neural-Singular-Hessian: Implicit Neural Representation of Unoriented Point Clouds by Enforcing Singular Hessian

Neural implicit representation is a promising approach for reconstructing surfaces from point clouds. Existing methods combine various regularization terms, such as the Eikonal and Laplacian energy terms, to enforce the learned neural function to possess the properties of a Signed Distance Function (SDF). However, inferring the actual topology and geometry of the underlying surface from poor-quality unoriented point clouds remains challenging. In accordance with Differential Geometry, the Hessian of the SDF is singular for points within the differential thin-shell space surrounding the surface. Our approach enforces the Hessian of the neural implicit function to have a zero determinant for points near the surface. This technique aligns the gradients for a near-surface point and its on-surface projection point, producing a rough but faithful shape within just a few iterations. By annealing the weight of the singular-Hessian term, our approach ultimately produces a high-fidelity reconstruction result. Extensive experimental results demonstrate that our approach effectively suppresses ghost geometry and recovers details from unoriented point clouds with better expressiveness than existing fitting-based methods

RhoA of the Rho Family Small GTPases Is Essential for B Lymphocyte Development

RhoA is a member of the Rho family small GTPases that are implicated in various cell functions including proliferation and survival. However, the physiological role of RhoA in vivo remains largely unknown. Here, we deleted RhoA in the B cell and hematopoietic stem cell (HSC) populations in RhoA flox/flox mice with CD19 and Mx promoter-driven Cre expression, respectively. Deletion of RhoA by CD19 Cre/+ significantly blocked B cell development in spleen, leading to a marked reduction in the number of transitional, marginal zone, and follicular B cells. Surprisingly, neither B cell proliferation in response to either LPS or B cell receptor (BCR) engagement nor B cell survival rate in vivo was affected by RhoA deletion. Furthermore, RhoA 2/2 B cells, like control cells, were rescued from apoptosis by BCR crosslinking in vitro. In contrast, RhoA deficiency led to a defect in B cell activating factor (BAFF)-mediated B cell survival that was associated with a dampened expression of BAFF receptor and a loss of BAFF-mediated Akt activation. Finally, HSC deletion of RhoA by Mx-Cre severely reduced proB/preB and immature B cell populations in bone marrow while common lymphoid progenitors were increased, indicating that RhoA is also required for B cell progenitor/precursor differentiation. Taken together, our results uncover an important role for RhoA at multiple stages of B cell development

Candle Soot-Based Electrosprayed Superhydrophobic Coatings for Self-Cleaning, Anti-Corrosion and Oil/Water Separation

The interest in candle soot (CS)-based superhydrophobic coatings has grown rapidly in recent years. Here, a simple and low-cost process has been developed for the fabrication of CS-based superhydrophobic coatings through electrospraying of the composite cocktail solution of CS and polyvinylidene fluoride (PVDF). Results show that the superhydrophobicity of the coating closely relates to the loading amount of CS which results in coatings with different roughnesses. Specifically, increasing the CS amount (not more than 0.4 g) normally enhances the superhydrophobicity of the coating due to higher roughness being presented in the produced microspheres. Further experiments demonstrate that the superhydrophobicity induced in the electrosprayed coating results from the synergistic effect of the cocktail solution and electrospray process, indicating the importance of the coating technique and the solution used. Versatile applications of CS-based superhydrophobic coatings including self-cleaning, anti-corrosion and oil/water separation are demonstrated. The present work provides a convenient method for the fabrication of CS-based superhydrophobic coatings, which is believed to gain great interest in the future

mTOR has a developmental stage-specific role in mitochondrial fitness independent of conventional mTORC1 and mTORC2 and the kinase activity.

The mammalian target of rapamycin (mTOR), present in mTOR complex 1 (mTORC1) and mTORC2, is a serine/threonine kinase that integrates nutrients, growth factors, and cellular energy status to control protein synthesis, cell growth, survival and metabolism. However, it remains elusive whether mTOR plays a developmental stage-specific role in tissue development and whether mTOR can function independent of its complexes and kinase activity. In this study, by inducible genetic manipulation approach, we investigated the role of mTOR and its dependence on mTOR complexes and kinase activity in mitochondrial fitness of early, progenitor stage (lineage-negative; Lin-) versus later, lineage-committed stage (lineage-positive; Lin+) of hematopoietic cells. We found that oxidative phosphorylation (OXPHOS), ATP production and mitochondrial DNA synthesis were decreased in mTOR-/- Lin- cells but increased in mTOR-/- Lin+ cells, suggesting that mTOR plays a developmental stage-specific role in OXPHOS, ATP production and mitochondrial DNA synthesis. In contrast to mTOR deletion, simultaneous deletion of Raptor, a key component of mTORC1, and Rictor, a key component of mTORC2, led to increased mitochondrial DNA in Lin- cells and decreased mitochondrial DNA and ATP production in Lin+ cells, suggesting that mTOR regulates mitochondrial DNA synthesis in Lin- and Lin+ cells and ATP production in Lin+ cells independent of mTORC1 and mTORC2. Similar to mTOR deletion, deletion of Raptor alone attenuated glycolysis and increased mitochondrial mass and mitochondrial membrane potential in Lin- cells and increased mitochondrial mass and OXPHOS in Lin+ cells, whereas deletion of Rictor alone had no effect on these mitochondrial parameters in Lin- and Lin+ cells, suggesting that mTOR regulates glycolysis and mitochondrial membrane potential in Lin- cells, OXPHOS in Lin+ cells, and mitochondrial mass in both Lin- and Lin+ cells dependent on mTORC1, but not mTORC2. Either Raptor deficiency or Rictor deficiency recapitulated mTOR deletion in decreasing OXPHOS in Lin- cells and glycolysis in Lin+ cells, suggesting that mTOR regulates OXPHOS in Lin- cells and glycolysis in Lin+ cells dependent on both mTORC1 and mTORC2. Finally, mice harboring a mTOR kinase dead D2338A knock-in mutant showed decreased glycolysis in Lin+ cells, as seen in mTOR-/- Lin+ cells, but no change in glycolysis in Lin- cells, in contrast to the decreased glycolysis in mTOR-/- Lin- cells, suggesting that mTOR regulates glycolysis in Lin+ cells dependent on its kinase activity, whereas mTOR regulates glycolysis in Lin- cells independent of its kinase activity

B cell-specific deletion of RhoA impairs splenic B cell development.

<p>(A) Generation of <i>RhoA^−/−</i> B cells. Left, the loxP/Cre-mediated gene targeting strategy to generate the <i>RhoA</i> knockout allele (<i>RhoA⁻</i>) in B cells. Right, Western blot showing RhoA expression in B220⁺ B cells purified from bone marrow and spleen of <i>CD19^Cre/+; RhoA^+/+</i> (control) and <i>CD19^Cre/+; RhoA^flox/flox</i> (<i>RhoA^−/−</i>) mice. (B) Bone marrow cells from control and <i>RhoA^−/−</i> mice were stained with antibodies against B220 and IgM and analyzed by flow cytometry (left). The number of B cell subsets was calculated by multiplying the total number of bone marrow cells by the percentage of each subset of cells (right). n = 5. (C) Splenocytes from control and <i>RhoA^−/−</i> mice were stained with antibodies against B220, CD21 and CD23 and analyzed by flow cytometry (left). The number of B cell subsets was calculated by multiplying the total number of splenocytes by the percentage of each subset of cells (right). T: transitional B cells, FO B: follicular B cells, and MZ B: marginal zone B cells. n = 5. (D) Spleen sections from control and <i>RhoA^−/−</i> mice, stained with hematoxylin and eosin. Data are representative of 3 mice. Error bars represent mean ± SD. **p<0.01. Statistical analysis was performed using a Student's unpaired t-test with a two-tailed distribution.</p

RhoA is necessary for BAFF-mediated B cell survival but not proliferation.

<p>(A) Splenic B220⁺ B cells from <i>CD19^Cre/+; RhoA^+/+</i> (control) and <i>CD19^Cre/+; RhoA^flox/flox</i> (<i>RhoA^−/−</i>) mice were cultured for 48 hours on 96-well plates (4×10⁵ cells/well) with or without (−) 2 µg/mL anti-IgM F(ab')₂ antibody or LPS. Cell growth rate was analyzed using the CellTiter 96® AQ_ueous Non-Radioactive Cell Proliferation Assay (MTS) kit. Data are expressed as absorbance OD₄₉₀. n = 5. (B) Splenocytes from control and <i>RhoA^−/−</i> mice were stained with anti-B220, -CD21, and -CD23 antibodies followed by Annexin V staining. The cells were then analyzed by flow cytometry. T: transitional B cells, FO B: follicular B cells, and MZ B: marginal zone B cells. n = 5. (C) Splenic B220⁺ B cells from control and <i>RhoA^−/−</i> mice were cultured for 72 hours on 96-well plates (2×10⁵ cells/well) with or without (−) 2 µg/mL anti-IgM F(ab')₂ antibody or indicated concentrations of BAFF (left). Alternatively, control B cells were incubated with or without (−) BAFF and/or Y27632 (10 µM) (right). The cells were then stained with Annexin V and analyzed by flow cytometry. n = 5. (D) Splenocytes from control and <i>RhoA^−/−</i> mice were stained with antibodies against B220, CD21, CD23 and BAFFR, and then analyzed by flow cytometry. The numbers above bracketed lines indicate the percentage of BAFFR⁺ cells in each B cell subset and the numbers below the bracketed lines indicate mean fluorescence intensity (MFI) of BAFFR in each B cell subset (left). The percentage of BAFFR⁺ cells and MFI of BAFFR were averaged from 5 mice for each genotype (right). (E) Splenic B220⁺ B cells from control and <i>RhoA^−/−</i> mice were subjected to Western blot for BAFFR and IgM (left). β-actin serves as loading control (left). The protein expression was quantified and normalized to β-actin and the data are expressed as fold of expression (right). n = 3. (F) Splenic B220⁺ B cells from control and <i>RhoA^−/−</i> mice were analyzed for BAFFR mRNA levels by quantitative RT-PCR. The expression of GAPDH was used to normalize samples and the relative fold of expression is shown. n = 4. (G) Splenic B220⁺ B cells from control and <i>RhoA^−/−</i> mice were stimulated with or without BAFF(100 ng/mL) for 30 min and then subjected to Western blot (left). Phospho (p)-Akt (S473) is quantified and normalized to total Akt and the data are expressed as relative fold of p-Akt (right). n = 3. Error bars represent mean ± SD. **p<0.01. *p<0.05. Statistical analysis was performed using a Student's unpaired t-test with a two-tailed distribution.</p

Mouse gene targeting reveals an essential role of mTOR in hematopoietic stem cell engraftment and hematopoiesis

mTOR integrates signals from nutrients and growth factors to control protein synthesis, cell growth, and survival. Although mTOR has been established as a therapeutic target in hematologic malignancies, its physiological role in regulating hematopoiesis remains unclear. Here we show that conditional gene targeting of mTOR causes bone marrow failure and defects in multi-lineage hematopoiesis including myelopoiesis, erythropoiesis, thrombopoiesis, and lymphopoiesis. mTOR deficiency results in loss of quiescence of hematopoietic stem cells, leading to a transient increase but long-term exhaustion and defective engraftment of hematopoietic stem cells in lethally irradiated recipient mice. Furthermore, ablation of mTOR causes increased apoptosis in lineage-committed blood cells but not hematopoietic stem cells, indicating a differentiation stage-specific function. These results demonstrate that mTOR is essential for hematopoietic stem cell engraftment and multi-lineage hematopoiesis

GBGVD: Growth-based geodesic Voronoi diagrams

Given a set of generators, the geodesic Voronoi diagram (GVD) defines how the base surface is decomposed into separate regions such that each generator dominates a region in terms of geodesic distance to the generators. Generally speaking, each ordinary bisector point of the GVD is determined by two adjacent generators while each branching point of the GVD is given by at least three generators. When there are sufficiently many generators, straight-line distance serves as an effective alternative of geodesic distance for computing GVDs. However, for a set of sparse generators, one has to use exact or approximate geodesic distance instead, which requires a high computational cost to trace the bisectors and the branching points. We observe that it is easier to infer the branching points by stretching the ordinary segments than competing between wavefronts from different directions. Based on the observation, we develop an unfolding technique to compute the ordinary points of the GVD, as well as a growth-based technique to stretch the traced bisector segments such that they finally grow into a complete GVD. Experimental results show that our algorithm runs 3 times as fast as the state-of-the-art method at the same accuracy level

Physicochemical, Nutritional Properties and Metabolomics Analysis Fat Deposition Mechanism of Chahua Chicken No. 2 and Yao Chicken

Poultry is an important dietary source of animal protein, accounting for approximately 30% of global meat consumption. Because of its low price, low fat and cholesterol content, and no religious restrictions, chicken is considered a widely available healthy meat. Chahua chicken No. 2 is a synthetic breed of Chahua chicken derived from five generations of specialized strain breeding. In this study, Chahua chicken No. 2 (CH) and Yao chicken (Y) were used as the research objects to compare the differences in physicochemical and nutritional indicators of meat quality between the two chicken breeds, and metabolomics was used to analyze the differences in metabolites and lipid metabolism pathways and to explore the expression of genes involved in adipogenesis. The physical index and nutritional value of CH are better than that of Y, and the chemical index of Y is better than that of CH. However, the chemical index results of CH are also within the normal theoretical value range. Comprehensive comparison shows that the meat quality of CH is relatively good. Metabolomics analysis showed that CH and Y had 85 different metabolites, and the differential metabolites were mainly classified into eight categories. KEGG pathway enrichment analysis revealed 13 different metabolic pathways. The screened PPARG, FABP3, ACSL5, FASN, UCP3 and SC5D were negatively correlated with muscle fat deposition, while PPAR&alpha;, ACACA and ACOX1 were positively correlated with muscle fat deposition. The meat quality of CH was better than Y. The metabolites and metabolic pathways obtained by metabonomics analysis mainly involved the metabolism of amino acids and fatty acids, which were consistent with the differences in meat quality between the two breeds and the contents of precursors affecting flavor. The screened genes were associated with fatty deposition in poultry