Tribological Properties of Polyimide Composites Modified with Diamondoid Metal-Organic Frameworks.

In this work, diamondoid metal-organic frameworks (MOFs) were efficiently prepared by sonochemical synthesis and grown on polyimide (PI), aiming to improve the anti-wear performance of the PI matrix. By introducing MOFs into the PI matrix, the free movement of PI molecular chains were restricted, and its hardness and elastic modulus were improved. It was found that the wear rate of the 3 wt.% MOFs/PI composites was reduced by 72.6% compared to pure PI at a load of 4 N after tribological testing by using a ball-on-disk tribometer. This can be attributed to the excellent load-bearing and shear resistance of the fourfold-interpenetrated diamondoid networks, in which the transition metal elements can favor the formation of transfer films. It is worth noting that the 3 wt.% MOFs/PI composites still exhibited great tribological properties under high loads or high speeds. The findings of the present study indicate that diamondoid metal-organic frameworks can be used as efficient modifiers to enhance the tribological properties of PI.

Unlocking the Therapeutic Potential of LncRNA BLACAT1 in Hypopharynx Squamous Cell Carcinoma.

BACKGROUND: Identifying the key molecular targets in hypopharynx squamous cell carcinoma (HSCC) is crucial for understanding this prevalent and highly fatal type of head and neck tumor. The study aims to enhance comprehension of the HSCC process by accurately identifying these key molecular targets. MATERIALS AND METHODS: In this study, we examined 47 clinical tissue samples from individuals diagnosed with HSCC using RNA-seq high-throughput assay. Quantitative real-time PCR (RT-PCR) was used to compare long non-coding RNA (lncRNA) bladder cancer-associated transcript 1 (BLACAT1) expression in HSCC tissues versus adjacent non-tumor tissues. The influence of highly expressed lncRNA BLACAT1 on prognostic survival was assessed. Subsequently, we cultured human pharynx squamous cell carcinoma FaDu cells. After reducing lncRNA BLACAT1 expression, we assessed FaDu cell proliferation, invasion, and migration using Cell Counting kit-8 (CCK-8) assay, colony formation assay, EUD assay, Transwell assay, and scratch assay. Additionally, liquid chromatography-tandem mass spectrometry/mass spectrometry (LC-MS/MS) and western blotting analysis were used to analyze proteins that bind to lncRNA BLACAT1. During in vivo experiments, mice received subcutaneous injections of FaDu cells transfected with lncRNA BLACAT1 shRNA or Scr plasmid (Control) in the dorsal region to observe and compare tumor growth. Lastly, tumor tissues underwent hematoxylin-eosin (HE) and immunohistochemical (IHC) staining. RESULTS: lncRNA BLACAT1 was screened as one of the most significant genes among the group of differentially expressed lncRNAs. RT-PCR exhibited elevated lncRNA BLACAT1 expression in HSCC tissues when compared to non-tumor tissues (p < 0.001). Furthermore, increased lncRNA BLACAT1 expression correlated with advanced clinical stages, heightened lymphatic invasion, and a poor prognosis. Subsequent in vitro experiments solidified our observations, demonstrating lncRNA BLACAT1's promotion of HSCC cell proliferation (p < 0.05), migration (p < 0.01), and invasion (p < 0.01) compared with the control group. Moreover, LC-MS/MS identified signal transducer and activator of transcription 3 (STAT3) and Prohibitin 2 (PHB2) as lncRNA BLACAT1-binding proteins and sh-lncRNA BLACAT1 inhibits STAT3/AKT phosphorylation (p < 0.01) and alters the subcellular distribution of PHB2 and P21 compared with the control group (p < 0.01). Moreover, in vivo experiments showed that lncRNA BLACAT1 inhibition suppresses tumorigenicity in an HSCC xenograft model compared to the control group (p < 0.01). CONCLUSIONS: lncRNA BLACAT1 is highly expressed in HSCC tumor tissues and plays a crucial role in the development of HSCC in vitro and in vivo. This increased expression may be caused by STAT3/AKT pathway activation, consequently inhibiting P21 expression through PHB2.

Systematic analysis of variants escaping nonsense-mediated decay uncovers candidate Mendelian diseases.

Protein-truncating variants (PTVs) near the 3' end of genes may escape nonsense-mediated decay (NMD). PTVs in the NMD-escape region (PTVescs) can cause Mendelian disease but are difficult to interpret given their varying impact on protein function. Previously, PTVesc burden was assessed in an epilepsy cohort, but no large-scale analysis has systematically evaluated these variants in rare disease. We performed a retrospective analysis of 29,031 neurodevelopmental disorder (NDD) parent-offspring trios referred for clinical exome sequencing to identify PTVesc de novo mutations (DNMs). We identified 1,376 PTVesc DNMs and 133 genes that were significantly enriched (binomial p < 0.001). The PTVesc-enriched genes included those with PTVescs previously described to cause dominant Mendelian disease (e.g., SEMA6B, PPM1D, and DAGLA). We annotated ClinVar variants for PTVescs and identified 948 genes with at least one high-confidence pathogenic variant. Twenty-two known Mendelian PTVesc-enriched genes had no prior evidence of PTVesc-associated disease. We found 22 additional PTVesc-enriched genes that are not well established to be associated with Mendelian disease, several of which showed phenotypic similarity between individuals harboring PTVesc variants in the same gene. Four individuals with PTVesc mutations in RAB1A had similar phenotypes including NDD and spasticity. PTVesc mutations in IRF2BP1 were found in two individuals who each had severe immunodeficiency manifesting in NDD. Three individuals with PTVesc mutations in LDB1 all had NDD and multiple congenital anomalies. Using a large-scale, systematic analysis of DNMs, we extend the mutation spectrum for known Mendelian disease-associated genes and identify potentially novel disease-associated genes.

A Disentangled Representation Based Brain Image Fusion via Group Lasso Penalty.

Complementary and redundant relationships inherently exist between multi-modal medical images captured from the same brain. Fusion processes conducted on intermingled representations can cause information distortion and the loss of discriminative modality information. To fully exploit the interdependency between source images for better feature representation and improve the fusion accuracy, we present the multi-modal brain medical image fusion method in a disentangled pipeline under the deep learning framework. A three-branch auto-encoder with two complementary branches and a redundant branch is designed to extract the exclusive modality features and common structure features from input images. Especially, to promote the disentanglement of complement and redundancy, a complementary group lasso penalty is proposed to constrain the extracted feature maps. Then, based on the disentangled representations, different fusion strategies are adopted for complementary features and redundant features, respectively. The experiments demonstrate the superior performance of the proposed fusion method in terms of structure preservation, visual quality, and running efficiency.

Claudin-1/4 as directly target gene of HIF-1α can feedback regulating HIF-1α by PI3K-AKT-mTOR and impact the proliferation of esophageal squamous cell though Rho GTPase and p-JNK pathway.

Immunohistochemical microarray comprising 80 patients with esophageal squamous cell carcinoma (ESCC) and discovered that the expression of CLDN1 and CLDN4 were significantly higher in cancer tissues compared to para-cancerous tissues. Furthermore, CLDN4 significantly affected the overall survival of cancer patients. When two ESCC cell lines (TE1, KYSE410) were exposed to hypoxia (0.1% O2), CLDN1/4 was shown to influence the occurrence and development of esophageal cancer. Compared with the control culture group, the cancer cells cultured under hypoxic conditions exhibited obvious changes in CLDN1 and CLDN4 expression at both the mRNA and protein levels. Through genetic intervention and Chip, we found that HIF-1α could directly regulate the expression of CLDN1 and CLDN4 in cancer cells. Hypoxia can affect the proliferation and apoptosis of cancer cells by regulating the PI3K-Akt-mTOR pathway. Molecular analysis further revealed that CLDN1 and CLDN4 can participate in the regulation process and had a feedback regulatory effect on HIF-1α expression in cancer cells. In vitro cellular experiments and vivo experiments in nude mice further revealed that changes in CLDN4 expression in cancer cells could affect the proliferation of cancer cells via regulation of Rho GTP and p-JNK pathway. Whether CLDN4 can be target for the treatment of ESCC needs further research.

PHF20 inhibition promotes apoptosis and cisplatin chemosensitivity via the OCT4­p­STAT3­MCL1 signaling pathway in hypopharyngeal squamous cell carcinoma.

Cisplatin is a widely used platinum­based chemotherapeutic agent for hypopharyngeal squamous cell carcinoma (HSCC). However, resistance to cisplatin limits its use for the treatment of HSCC, and the underlying molecular mechanism requires further investigation. The present study performed functional assays to determine whether the expression of plant homeodomain finger protein 20 (PHF20) may be involved in the apoptosis and cisplatin resistance of HSCC. The expression levels of PHF20 were higher in cisplatin­resistant HSCC cells compared with those in cisplatin­sensitive cells. The inhibition of PHF20 suppressed cell viability but did not affect the migratory and invasive abilities of HSCC cells compared with those of negative control­transfected cells. Furthermore, PHF20 inhibition reduced cell viability by enhancing apoptosis compared with those in the control cells in vitro. Notably, the inhibition of PHF20 sensitized HSCC cells to cisplatin, thus increasing apoptosis via the signal transducer and activator of transcription 3 (STAT3)­myeloid cell leukemia­1 (MCL1) pathway. Octamer­binding transcription factor 4 (OCT4) overexpression restored phosphorylated STAT3­MCL1­mediated apoptosis induced by PHF20 inhibition. In vivo experiments confirmed that PHF20 silencing induced tumor growth and increased apoptosis in HSCC cells compared with those in the control cells. Thus, PHF20 inhibition may promote apoptosis and improve cisplatin chemosensitivity via the OCT4­p­STAT3­MCL1 signaling pathway in HSCC.

Evidence for 28 genetic disorders discovered by combining healthcare and research data.

De novo mutations in protein-coding genes are a well-established cause of developmental disorders1. However, genes known to be associated with developmental disorders account for only a minority of the observed excess of such de novo mutations1,2. Here, to identify previously undescribed genes associated with developmental disorders, we integrate healthcare and research exome-sequence data from 31,058 parent-offspring trios of individuals with developmental disorders, and develop a simulation-based statistical test to identify gene-specific enrichment of de novo mutations. We identified 285 genes that were significantly associated with developmental disorders, including 28 that had not previously been robustly associated with developmental disorders. Although we detected more genes associated with developmental disorders, much of the excess of de novo mutations in protein-coding genes remains unaccounted for. Modelling suggests that more than 1,000 genes associated with developmental disorders have not yet been described, many of which are likely to be less penetrant than the currently known genes. Research access to clinical diagnostic datasets will be critical for completing the map of genes associated with developmental disorders.

Mobile element insertion detection in 89,874 clinical exomes.

PURPOSE: Exome sequencing (ES) is increasingly used for the diagnosis of rare genetic disease. However, some pathogenic sequence variants within the exome go undetected due to the technical difficulty of identifying them. Mobile element insertions (MEIs) are a known cause of genetic disease in humans but have been historically difficult to detect via ES and similar targeted sequencing methods. METHODS: We developed and applied a novel MEI detection method prospectively to samples received for clinical ES beginning in November 2017. Positive MEI findings were confirmed by an orthogonal method and reported back to the ordering provider. In this study, we examined 89,874 samples from 38,871 cases. RESULTS: Diagnostic MEIs were present in 0.03% (95% binomial test confidence interval: 0.02-0.06%) of all cases and account for 0.15% (95% binomial test confidence interval: 0.08-0.25%) of cases with a molecular diagnosis. One diagnostic MEI was a novel founder event. Most patients with pathogenic MEIs had prior genetic testing, three of whom had previous negative DNA sequencing analysis of the diagnostic gene. CONCLUSION: MEI detection from ES is a valuable diagnostic tool, reveals molecular findings that may be undetected by other sequencing assays, and increases diagnostic yield by 0.15%.

Sex-Based Analysis of De Novo Variants in Neurodevelopmental Disorders.

While genes with an excess of de novo mutations (DNMs) have been identified in children with neurodevelopmental disorders (NDDs), few studies focus on DNM patterns where the sex of affected children is examined separately. We considered ∼8,825 sequenced parent-child trios (n ∼26,475 individuals) and identify 54 genes with a DNM enrichment in males (n = 18), females (n = 17), or overlapping in both the male and female subsets (n = 19). A replication cohort of 18,778 sequenced parent-child trios (n = 56,334 individuals) confirms 25 genes (n = 3 in males, n = 7 in females, n = 15 in both male and female subsets). As expected, we observe significant enrichment on the X chromosome for females but also find autosomal genes with potential sex bias (females, CDK13, ITPR1; males, CHD8, MBD5, SYNGAP1); 6.5% of females harbor a DNM in a female-enriched gene, whereas 2.7% of males have a DNM in a male-enriched gene. Sex-biased genes are enriched in transcriptional processes and chromatin binding, primarily reside in the nucleus of cells, and have brain expression. By downsampling, we find that DNM gene discovery is greatest when studying affected females. Finally, directly comparing de novo allele counts in NDD-affected males and females identifies one replicated genome-wide significant gene (DDX3X) with locus-specific enrichment in females. Our sex-based DNM enrichment analysis identifies candidate NDD genes differentially affecting males and females and indicates that the study of females with NDDs leads to greater gene discovery consistent with the female-protective effect.

Age-adjusted association of homologous recombination genes with ovarian cancer using clinical exomes as controls.

BACKGROUND: Genes in the homologous recombination pathway have shown varying results in the literature regarding ovarian cancer (OC) association. Recent case-control studies have used allele counts alone to quantify genetic associations with cancer. METHODS: A retrospective case-control study was performed on 6,182 women with OC referred for hereditary cancer multi-gene panel testing (cases) and 4,690 mothers from trios who were referred for whole-exome sequencing (controls). We present age-adjusted odds ratios (ORAdj) to determine association of OC with pathogenic variants (PVs) in homologous recombination genes. RESULTS: Significant associations with OC were observed in BRCA1, BRCA2, RAD51C and RAD51D. Other homologous recombination genes, BARD1, NBN, and PALB2, were not significantly associated with OC. ATM and CHEK2 were only significantly associated with OC by crude odds ratio (ORCrude) or by ORAdj, respectively. However, there was no significant difference between ORCrude and ORAdj for these two genes. The significant association of PVs in BRIP1 by ORCrude (2.05, CI = 1.11 to 3.94, P = 0.03) was not observed by ORAdj (0.87, CI = 0.41 to 1.93, P = 0.73). Interestingly, the confidence intervals of the two effect sizes were significantly different (P = 0.04). CONCLUSION: The lack of association of PVs in BRIP1 with OC by ORAdj is inconsistent with some previous literature and current management recommendations, highlighted by the significantly older age of OC onset for BRIP1 PV carriers compared to non-carriers. By reporting ORAdj, this study presents associations that reflect more informed genetic contributions to OC when compared to traditional count-based methods.

Biallelic Mutations in MRPS34 Lead to Instability of the Small Mitoribosomal Subunit and Leigh Syndrome.

The synthesis of all 13 mitochondrial DNA (mtDNA)-encoded protein subunits of the human oxidative phosphorylation (OXPHOS) system is carried out by mitochondrial ribosomes (mitoribosomes). Defects in the stability of mitoribosomal proteins or mitoribosome assembly impair mitochondrial protein translation, causing combined OXPHOS enzyme deficiency and clinical disease. Here we report four autosomal-recessive pathogenic mutations in the gene encoding the small mitoribosomal subunit protein, MRPS34, in six subjects from four unrelated families with Leigh syndrome and combined OXPHOS defects. Whole-exome sequencing was used to independently identify all variants. Two splice-site mutations were identified, including homozygous c.321+1G>T in a subject of Italian ancestry and homozygous c.322-10G>A in affected sibling pairs from two unrelated families of Puerto Rican descent. In addition, compound heterozygous MRPS34 mutations were identified in a proband of French ancestry; a missense (c.37G>A [p.Glu13Lys]) and a nonsense (c.94C>T [p.Gln32∗]) variant. We demonstrated that these mutations reduce MRPS34 protein levels and the synthesis of OXPHOS subunits encoded by mtDNA. Examination of the mitoribosome profile and quantitative proteomics showed that the mitochondrial translation defect was caused by destabilization of the small mitoribosomal subunit and impaired monosome assembly. Lentiviral-mediated expression of wild-type MRPS34 rescued the defect in mitochondrial translation observed in skin fibroblasts from affected subjects, confirming the pathogenicity of MRPS34 mutations. Our data establish that MRPS34 is required for normal function of the mitoribosome in humans and furthermore demonstrate the power of quantitative proteomic analysis to identify signatures of defects in specific cellular pathways in fibroblasts from subjects with inherited disease.

Heartbeat classification using disease-specific feature selection.

Automatic heartbeat classification is an important technique to assist doctors to identify ectopic heartbeats in long-term Holter recording. In this paper, we introduce a novel disease-specific feature selection method which consists of a one-versus-one (OvO) features ranking stage and a feature search stage wrapped in the same OvO-rule support vector machine (SVM) binary classifier. The proposed method differs from traditional approaches in that it focuses on the selection of effective feature subsets for distinguishing a class from others by making OvO comparison. The electrocardiograms (ECG) from the MIT-BIH arrhythmia database (MIT-BIH-AR) are used to evaluate the proposed feature selection method. The ECG features adopted include inter-beat and intra-beat intervals, amplitude morphology, area morphology and morphological distance. Following the recommendation of the Advancement of Medical Instrumentation (AAMI), all the heartbeat samples of MIT-BIH-AR are grouped into four classes, namely, normal or bundle branch block (N), supraventricular ectopic (S), ventricular ectopic (V) and fusion of ventricular and normal (F). The division of training and testing data complies with the inter-patient schema. Experimental results show that the average classification accuracy of the proposed feature selection method is 86.66%, outperforming those methods without feature selection. The sensitivities for the classes N, S, V and F are 88.94%, 79.06%, 85.48% and 93.81% respectively, and the corresponding positive predictive values are 98.98%, 35.98%, 92.75% and 13.74% respectively. In terms of geometric means of sensitivity and positive predictivity, the proposed method also demonstrates better performance than other state-of-the-art feature selection methods.

Generalized locality preserving Maxi-Min Margin Machine.

Research on large margin classifiers from the "local" and "global" view has become an active topic in machine learning and pattern recognition. Inspired from the typical local and global learning machine Maxi-Min Margin Machine (M4) and the idea of the Locality Preserving Projections (LPP), we propose a novel large margin classifier, the Generalized Locality Preserving Maxi-Min Margin Machine (GLPM), where the within-class matrices are constructed using the labeled training points in a supervised way, and then used to build the classifier. The within-class matrices of GLPM preserve the intra-class manifold in the training sets, as well as the covariance matrices which indicate the global projection direction in the M4 model. Moreover, the connections among GLPM, M4 and LFDA are theoretically analyzed, and we show that GLPM can be considered as a generalized M4 machine. The GLPM is also more robust since it requires no assumption on data distribution while Gaussian data distribution is assumed in the M4 machine. Experiments on data sets from the machine learning repository demonstrate its advantage over M4 in both local and global learning performance.

The accessible chromatin landscape of the human genome.

DNase I hypersensitive sites (DHSs) are markers of regulatory DNA and have underpinned the discovery of all classes of cis-regulatory elements including enhancers, promoters, insulators, silencers and locus control regions. Here we present the first extensive map of human DHSs identified through genome-wide profiling in 125 diverse cell and tissue types. We identify ∼2.9 million DHSs that encompass virtually all known experimentally validated cis-regulatory sequences and expose a vast trove of novel elements, most with highly cell-selective regulation. Annotating these elements using ENCODE data reveals novel relationships between chromatin accessibility, transcription, DNA methylation and regulatory factor occupancy patterns. We connect ∼580,000 distal DHSs with their target promoters, revealing systematic pairing of different classes of distal DHSs and specific promoter types. Patterning of chromatin accessibility at many regulatory regions is organized with dozens to hundreds of co-activated elements, and the transcellular DNase I sensitivity pattern at a given region can predict cell-type-specific functional behaviours. The DHS landscape shows signatures of recent functional evolutionary constraint. However, the DHS compartment in pluripotent and immortalized cells exhibits higher mutation rates than that in highly differentiated cells, exposing an unexpected link between chromatin accessibility, proliferative potential and patterns of human variation.

Open chromatin defined by DNaseI and FAIRE identifies regulatory elements that shape cell-type identity.

The human body contains thousands of unique cell types, each with specialized functions. Cell identity is governed in large part by gene transcription programs, which are determined by regulatory elements encoded in DNA. To identify regulatory elements active in seven cell lines representative of diverse human cell types, we used DNase-seq and FAIRE-seq (Formaldehyde Assisted Isolation of Regulatory Elements) to map "open chromatin." Over 870,000 DNaseI or FAIRE sites, which correspond tightly to nucleosome-depleted regions, were identified across the seven cell lines, covering nearly 9% of the genome. The combination of DNaseI and FAIRE is more effective than either assay alone in identifying likely regulatory elements, as judged by coincidence with transcription factor binding locations determined in the same cells. Open chromatin common to all seven cell types tended to be at or near transcription start sites and to be coincident with CTCF binding sites, while open chromatin sites found in only one cell type were typically located away from transcription start sites and contained DNA motifs recognized by regulators of cell-type identity. We show that open chromatin regions bound by CTCF are potent insulators. We identified clusters of open regulatory elements (COREs) that were physically near each other and whose appearance was coordinated among one or more cell types. Gene expression and RNA Pol II binding data support the hypothesis that COREs control gene activity required for the maintenance of cell-type identity. This publicly available atlas of regulatory elements may prove valuable in identifying noncoding DNA sequence variants that are causally linked to human disease.

Orientational dynamics of water in phospholipid bilayers with different hydration levels.

We performed molecular dynamics computer simulations to study the orientational dynamics of water next to bilayers containing dilauroyl phosphatidylcholine (DLPC) phospholipids with different hydration levels: from 2 to 32 water molecules per lipid. It was observed that water orientational relaxation slowed down as the hydration level of lipids was reduced, in agreement with the recent experimental study. We performed different fits for some of the relaxation curves and observed that fit constants depend strongly on the time period over which the correlation function was measured. We also studied hydrogen bonding properties of water and found that hydrogen bonding switch between water molecules is responsible for a substantial orientational relaxation and that this switch can be explained by the molecular jump model (MJM) in the hydration region of lipid bilayers, as it does in bulk water.

Energetics of cholesterol transfer between lipid bilayers.

It is believed that natural biological membranes contain domains of lipid ordered phase enriched in cholesterol and sphingomyelin. Although the existence of these domains, called lipid rafts, is still not firmly established for natural membranes, direct microscopic observations and phase diagrams obtained from the study of three-component mixtures containing saturated phospholipids, unsaturated phospholipids, and cholesterol demonstrate the existence of lipid rafts in synthetic membranes. The presence of the domains or rafts in these membranes is often ascribed to the preferential interactions between cholesterol and saturated phospholipids, for example, between cholesterol and sphingomyelin. In this work, we calculate, using molecular dynamics computer simulation technique, the free energy of cholesterol transfer from the bilayer containing unsaturated phosphatidylcholine lipid molecules to the bilayer containing sphingomyelin molecules and find that the affinity of cholesterol to sphingomyelin is higher. Our calculations of the free-energy components, energy and entropy, show that cholesterol transfer is exothermic and promoted by the favorable change in the lipid-lipid interactions near cholesterol and not by the favorable energy of cholesterol-sphingomyelin interaction, as assumed previously.

Molecular dynamics simulations of bilayers containing mixtures of sphingomyelin with cholesterol and phosphatidylcholine with cholesterol.

We performed six molecular dynamics simulations: three on hydrated bilayers containing pure phospholipids and three on hydrated bilayers containing mixtures of these phospholipids with cholesterol. The phospholipids in our simulations were SSM (sphingomyelin containing a saturated 18:0 acyl chain), OSM (sphingomyelin with an unsaturated 18:1 acyl chain), and POPC (palmitoyloleoylphosphatidylcholine containing one saturated and one unsaturated chain). Data from our simulations were used to study systematically the effect of cholesterol on phospholipids that differed in their headgroup and tail composition. In addition to the structural analysis, we performed an energetic analysis and observed that energies of interaction between cholesterol and neighboring SM molecules are similar to the energies of interaction between cholesterol and POPC. We also observed that the interaction energy between cholesterol and neighboring lipids cannot be used for the determination of which lipids are involved in the creation of a complex.

Molecular dynamics simulations of SOPS and sphingomyelin bilayers containing cholesterol.

We performed a molecular dynamics simulation of an asymmetric bilayer that contained different lipid mixtures in its outer and inner leaflets. The outer leaflet contained a mixture of sphingomyelin (SM) with cholesterol and the inner leaflet a mixture of stearoyl-oleoyl-phosphatidylserine (SOPS) with cholesterol. For comparison purposes, we also performed two simulations on symmetric bilayers: the first simulation was performed on a bilayer containing a binary mixture of SOPS with cholesterol; the second contained a mixture of SM with cholesterol. We studied the hydrogen-bonding network of the bilayers in our simulations and the difference in the network properties in the monolayers either with SM or SOPS. We observed that in the asymmetric bilayer the properties of monolayers were the same as in the corresponding monolayers in the symmetric bilayers.