Physics-Guided Dual Self-Supervised Learning for Structure-Based Material Property Prediction

Deep learning models have been widely used for high-performance material property prediction. However, training such models usually requires a large amount of labeled data, which are usually unavailable. Self-supervised learning (SSL) methods have been proposed to address this data scarcity issue. Herein, we present DSSL, a physics-guided dual SSL framework, for graph neural network-based material property prediction, which combines node masking-based generative SSL with atomic coordinate perturbation-based contrastive SSL strategies to capture local and global information about input crystals. Moreover, we achieve physics-guided pretraining by using the macroproperty (e.g., elasticity)-related microproperty prediction of atomic stiffness as an additional pretext task. We pretrain our DSSL model on the Materials Project database and fine-tune it with 10 material property data sets. The experimental results demonstrate that teaching neural networks some physics using the SSL strategy can afford ≤26.89% performance improvement compared to that of the baseline models.

Composition Based Oxidation State Prediction of Materials Using Deep Learning Language Models

Oxidation states (OS) are the charges on atoms due to electrons gained or lost upon applying an ionic approximation to their bonds. As a fundamental property, OS has been widely used in charge-neutrality verification, crystal structure determination, and reaction estimation. Currently, only heuristic rules exist for guessing the oxidation states of a given compound with many exceptions. Recent work has developed machine learning models based on heuristic structural features for predicting the oxidation states of metal ions. However, composition-based oxidation state prediction still remains elusive so far, which has significant implications for the discovery of new materials for which the structures have not been determined. This work proposes a novel deep learning-based BERT transformer language model BERTOS for predicting the oxidation states for all elements of inorganic compounds given only their chemical composition. This model achieves 96.82% accuracy for all-element oxidation states prediction benchmarked on the cleaned ICSD dataset and achieves 97.61% accuracy for oxide materials. It is also demonstrated how it can be used to conduct large-scale screening of hypothetical material compositions for materials discovery.

Probabilistic generative transformer language models for generative design of molecules

Self-supervised neural language models have recently found wide applications in the generative design of organic molecules and protein sequences as well as representation learning for downstream structure classification and functional prediction. However, most of the existing deep learning models for molecule design usually require a big dataset and have a black-box architecture, which makes it difficult to interpret their design logic. Here we propose the Generative Molecular Transformer (GMTransformer), a probabilistic neural network model for generative design of molecules. Our model is built on the blank filling language model originally developed for text processing, which has demonstrated unique advantages in learning the "molecules grammars" with high-quality generation, interpretability, and data efficiency. Benchmarked on the MOSES datasets, our models achieve high novelty and Scaf compared to other baselines. The probabilistic generation steps have the potential in tinkering with molecule design due to their capability of recommending how to modify existing molecules with explanation, guided by the learned implicit molecule chemistry. The source code and datasets can be accessed freely at https://github.com/usccolumbia/GMTransformer.

Global Mapping of Structures and Properties of Crystal Materials

Understanding materials' composition-structure-function relationships is of critical importance for the design and discovery of novel functional materials. While most such studies focus on individual materials, we conducted a global mapping study of all known materials deposited in the Materials Project database to investigate their distributions in the space of a set of seven compositional, structural, physical, and neural latent descriptors. These two-dimensional materials maps along with their density maps allow us to illustrate the distribution of the patterns and clusters of different shapes, which indicates the propensity of these materials and the tinkering history of existing materials. We then overlap the material properties such as composition prototypes and piezoelectric properties over the background material maps to study the relationships of how material compositions and structures affect their physical properties. We also use these maps to study the spatial distributions of properties of known inorganic materials, in particular those of local vicinities in structural space such as structural density and functional diversity. These maps provide a uniquely comprehensive overview of materials and space and thus reveal previously undescribed fundamental properties. Our methodology can be easily extended by other researchers to generate their own global material maps with different background maps and overlap properties for both distribution understanding and cluster-based new material discovery. The source code for feature generation and generated maps is available at https://github.com/usccolumbia/matglobalmapping.

Simultaneously-Collected Multimodal Lying Pose Dataset: Enabling In-Bed Human Pose Monitoring

Computer vision field has achieved great success in interpreting semantic meanings from images, yet its algorithms can be brittle for tasks with adverse vision conditions and the ones suffering from data/label pair limitation. Among these tasks is in-bed human pose monitoring with significant value in many healthcare applications. In-bed pose monitoring in natural settings involves pose estimation in complete darkness or full occlusion. The lack of publicly available in-bed pose datasets hinders the applicability of many successful human pose estimation algorithms for this task. In this paper, we introduce our Simultaneously-collected multimodal Lying Pose (SLP) dataset, which includes in-bed pose images from 109 participants captured using multiple imaging modalities including RGB, long wave infrared (LWIR), depth, and pressure map. We also present a physical hyper parameter tuning strategy for ground truth pose label generation under adverse vision conditions. The SLP design is compatible with the mainstream human pose datasets; therefore, the state-of-the-art 2D pose estimation models can be trained effectively with the SLP data with promising performance as high as 95% at PCKh@0.5 on a single modality. The pose estimation performance of these models can be further improved by including additional modalities through the proposed collaborative scheme.

MATERIAL TRANSFORMERS: DEEP LEARNING LANGUAGE MODELS FOR GENERATIVE MATERIALS DESIGN

Pre-trained transformer language models on large unlabeled corpus have produced state-of-the-art results in natural language processing, organic molecule design, and protein sequence generation. However, no such models have been applied to learn the composition patterns for generative design of material compositions. Here we train a series of seven modern transformer models (GPT, GPT-2, GPT-Neo, GPT-J, BLMM, BART, and RoBERTa) for materials design using the expanded formulas of the ICSD, OQMD, and Materials Projects databases. Six different datasets with/out non-charge-neutral or balanced electronegativity samples are used to benchmark the generative design performances and uncover the biases of modern transformer models for the generative design of materials compositions. Our experiments show that the materials transformers based on causal language models can generate chemically valid materials compositions with as high as 97.54\% to be charge neutral and 91.40\% to be electronegativity balanced, which has more than six times higher enrichment compared to the baseline pseudo-random sampling algorithm. Our language models also demonstrate high generation novelty and their potential in new materials discovery is proved by their capability to recover the leave-out materials. We also find that the properties of the generated compositions can be tailored by training the models with selected training sets such as high-bandgap samples. Our experiments also show that different models each have their own preference in terms of the properties of the generated samples and their running time complexity varies a lot. We have applied our materials transformers to discover a set of new materials as validated using DFT calculations. All our trained materials transformer models and code can be accessed freely at \url{http://www.github.com/usccolumbia/MTransformer}.

DeepXRD, a Deep Learning Model for Predicting XRD spectrum from Material Composition

One of the long-standing problems in materials science is how to predict a material's structure and then its properties given only its composition. Experimental characterization of crystal structures has been widely used for structure determination, which is, however, too expensive for high-throughput screening. At the same time, directly predicting crystal structures from compositions remains a challenging unsolved problem. Herein we propose a deep learning algorithm for predicting the XRD spectrum given only the composition of a material, which can then be used to infer key structural features for downstream structural analysis such as crystal system or space group classification or crystal lattice parameter determination or materials property prediction. Benchmark studies on two data sets show that our DeepXRD algorithm can achieve good performance for XRD prediction as evaluated over our test sets. It can thus be used in high-throughput screening in the huge materials composition space for materials discovery.

Implementing hybrid telerehabilitation following major cardiac surgery during COVID-19 pandemic in Hong Kong

Funding Acknowledgements

Type of funding sources: Public hospital(s). Main funding source(s): Department budget

Background

Aerobic exercise is a critical component of cardiac rehabilitation (CR) for patients (pts) who have undergone cardiac surgery. Exercise-based CR is ideally home-based and directly supervised by a trained physiotherapist. During COVID-19 pandemic in Hong Kong, there was increasing emphasis on social distancing and caregiving strategies to better reach pts outside hospital. As most cardiac surgeries were performed on urgent clinical needs including heart transplantation and aortic dissection, we implemented hybrid telerehabilitation (HTR) with transition to the use of remote care in order to continue comprehensive CR. We report the functional outcome of HTR group compared with usual care (UC) group.

Methods

From 7/2020 to10/2021, 36 pts ( 67% men, mean age 57±9.2 years) were enrolled into HTR (n=18) and UC (n=18) groups respectively for 12 weeks’ duration. Demographics in both groups were similar. Types of cardiac surgeries were heart transplant (n=5; 14%), CABG (n=6;17%), valvular surgery (n=17; 47%) and aorta operation (n=8; 22%). An individualized exercise prescription for HTR at home was determined based on initial standardized assessments in hospital and tailored to fit lifestyle and home environment. For HTR group, the goal is set at 150 minutes of low to moderate-intensity aerobic exercise per week at home. Exercise is progressed weekly based on daily metrics recorded by wearable device (exercise log and % target heart rate reserve (THRR) attained) and rate of perceived exertion (RPE). These were reported by pts through an online survey after each exercise session which were reviewed daily, with progress follow-up by phone calls or text messages on a weekly basis.

Functional capacity parameters were evaluated using symptom limited exercise treadmill test (ETT) and 6 minute walk test (6MWT). The advised level is based on the current activity level of the patient using a MET score list at intake by the physiotherapist. Handgrip and quadriceps strength were measured.

Results

All pts participated the programs. Both groups demonstrated significant improvement in MET scores and 6MWT after completion of CR programs.(Table ) Average exercise time at home was reported to be 379 ±98 minutes/ week (72% achieved >150 minutes/ week). Compared with UC, HTR showed significantly increased % change in MET score at baseline and upon completion of CR (22.1% vs 7%; p=0.02) and 6MWT (11.1% vs 5.3%; p=0.01). The effect muscle strength were similar in both groups with improving trend but no significant % change at baseline and end of CR.

Conclusion

Significant improvement in functional status can be demonstrated in comprehensive individualized HTR program in pts after major cardiac surgery. Adoption of digital technology with full integration into standard cardiac rehabilitation program should be recommended.

TCSP: a Template-Based Crystal Structure Prediction Algorithm for Materials Discovery

Fast and accurate crystal structure prediction (CSP) algorithms and web servers are highly desirable for the exploration and discovery of new materials out of the infinite chemical design space. However, currently, the computationally expensive first-principles calculation-based CSP algorithms are applicable to relatively small systems and are out of reach of most materials researchers. Several teams have used an element substitution approach for generating or predicting new structures, but usually in an ad hoc way. Here we develop a template-based crystal structure prediction (TCSP) algorithm and its companion web server, which makes this tool accessible to all materials researchers. Our algorithm uses elemental/chemical similarity and oxidation states to guide the selection of template structures and then rank them based on the substitution compatibility and can return multiple predictions with ranking scores in a few minutes. A benchmark study on the 98290 formulas of the Materials Project database using leave-one-out evaluation shows that our algorithm can achieve high accuracy (for 13145 target structures, TCSP predicted their structures with root-mean-square deviation < 0.1) for a large portion of the formulas. We have also used TCSP to discover new materials of the Ga-B-N system, showing its potential for high-throughput materials discovery. Our user-friendly web app TCSP can be accessed freely at www.materialsatlas.org/crystalstructure on our MaterialsAtlas.org web app platform.

Glycosylated hemoglobin levels and the risk for contrast-induced nephropathy in diabetic patients undergoing coronary arteriography/percutaneous coronary intervention

Backgrounds

Diabetes mellitus is an independent risk factor for Contrast-induced nephropathy (CIN) in patients undergoing Coronary arteriography (CAG)/percutaneous coronary intervention (PCI). Glycosylated hemoglobin (HbA1c) is the gold standard to measure blood glucose control, which has important clinical significance for evaluating blood glucose control in diabetic patients in the past 3 months. This study aimed to assess whether preoperative HbA1c levels in diabetic patients who received CAG/PCI impacted the occurrence of postoperative CIN.

Methods

We reviewed the incidence of preoperative HbA1c and postoperative CIN in 670 patients with CAG/PCI from January 1, 2020 to October 30, 2020 and divided the preoperative HbA1c levels into 5 groups. Blood samples were collected at admission, 48 h and 72 h after operation to measure the Scr value of patients. Categorical variables were compared using a chi-square test, and continuous variables were compared using an analysis of variance. Fisher’s exact test was used to compare the percentages when the expected frequency was less than 5. Univariable and multivariable logistic regression analysis was used to exclude the influence of confounding factors, and P for trend was used to analyze the trend between HbA1c levels and the increased risk of CIN.

Results

Patients with elevated HbA1c had higher BMI, FBG, and LDL-C, and they were more often on therapy with hypoglycemic agents, Insulin and PCI. They also had higher basal, 48 h and 72 h Scr. The incidence of CIN in the 5 groups of patients were: 9.8, 11.9, 15.2, 25.3, 48.1%. (p < 0.0001) The multivariate analysis confirmed that in the main high-risk subgroup, patients with elevated HbA1C levels (≥8.8%) had a higher risk of CIN disease. Trend test showed the change of OR (1.000,1.248,1.553,2.625,5.829).

Conclusions

Studies have shown that in diabetic patients undergoing CAG/PCI, elevated HbA1c is independently associated with the risk of CIN, and when HbA1c > 9.5%, the incidence of CIN trends increase. Therefore, we should attach great importance to patients with elevated HbA1c at admission and take more active measures to prevent CIN.

P101 Cardiac rehabilitation program for end-stage heart failure patients with left ventricular assist devices in Hong Kong

Background

Implantation of modern durable left ventricular assist device (LVAD) in advanced heart failure (HF) patients is associated with increased survival and improved quality of life. Exercise-based cardiac rehabilitation (EBCR) has been demonstrated to exercise capacity in HF patients but data on effect of EBCR in advanced HF patients with LVAD are limited.

Objectives

To evaluate the effect of EBCR program  on the functional capacity of advanced heart failure patients with LVAD

Methods

Out of  the current 64 LVAD recipients in Hong Kong, 43 patients who have had LVAD implanted and survived 1 year were screened.  The EBCRP consisted of cardiorespiratory and strength training exercise once a week for a total of 24 sessions (6 months). The functional rehabilitation outcome  was evaluated by 6 minute walk test (6MWT) at baseline, before LVAD implantation, pre-EBCR and by end of EBCP ( 6 months). The muscle strength was evaluated by an isokinetic knee extension strength test defined by 10 repetitive maximum (RM) torque of quadriceps strength before starting EBCR and at 6 months upon termination of EBCR.

Results

A total of 33 LVAD patients were recruited into our EBCR program. There were 27 (82%) men with mean age of 48.7± 13.6 years. Average duration from LVAD surgery to commencement of EBCR was 5.3 months. Baseline 6MWT could not be performed in 21 patients due to extreme poor functional class (NYHA class IV) with prolonged hospitalizations requiring inotropes and circulatory support. For the other 12 patients, there were no significant differences in 6 MWT at baseline and post LVAD before starting EBCP. Overall 6MWT significantly improved by end of EBCR (pre- EBCR mean 382.2, ±95.2m vs  post -EBCR mean 440.8 ±88.2m  p= 0.001). There were significant improvement in quadriceps strength by the end of EBCRP program. (pre- CRP 1.8 ± 2.5 kg vs post CRP 3.5 ± 3.5 kg p &lt; 0.001).

Conclusions

LVAD patients show high level of impairment of functional capacity despite after LVAD imaplntation with improved circulatory output. EBCR program allowed greater improvement in exercise capacity evolution and peripheral physiology such as muscle strengthening.

[An interpretation of the AASLD practice guideline on the diagnosis and management of nonalcoholic fatty liver disease in 2017]

The American Association for the Study of Liver Diseases (AASLD) updated and published the Practice Guidance for the Diagnosis and Management of Nonalcoholic Fatty Liver Disease (NAFLD) in July 2017, which provides recommendations for the accurate diagnosis, treatment, and effective prevention of NAFLD. Related metabolic diseases should be considered during the initial evaluation of patients suspected of NAFLD. Noninvasive diagnostic techniques including transient elastography, magnetic resonance elastography, and serum biochemical models should be used to evaluate the development and progression of liver fibrosis in patients with NAFLD. Clinical liver pathology report should clearly differentiate between nonalcoholic fatty liver (NAFL), NAFL with inflammation, and nonalcoholic steatohepatitis (NASH) and identify the presence or absence of liver fibrosis and its degree. Early medication for NAFLD can only be used in patients with pathologically confirmed NASH and liver fibrosis, and it is not recommended to use pioglitazone and vitamin E as the first-line drugs for patients with NASH which has not been proven by biopsy or non-diabetic NASH patients. Foregut bariatric surgery can be considered for obese patients with NAFLD/NASH who meet related indications. It is emphasized that the risk factors for cardiovascular disease should be eliminated for NAFLD patients. Statins can be used for the treatment of dyslipidemia in patients with NAFLD/NASH, but they cannot be used in patients with decompensated liver cirrhosis. Routine screening or hepatocellular carcinoma surveillance is not recommended for NASH patients without liver cirrhosis. Cardiovascular disease should be taken seriously during liver transplantation evaluation. There is still no adequate clinical evidence for the treatment of NAFLD in children and adolescents, and intensive lifestyle intervention is recommended as the first-line therapy for such patients.

Comparative efficacy of adjuvant trastuzumab-containing chemotherapies for patients with early HER2-positive primary breast cancer: a network meta-analysis

BACKGROUND

Trastuzumab (H) with chemotherapy benefits patients with HER2+ breast cancer (BC); however, we lack head-to-head pairwise assessment of survival or cardiotoxicity for specific combinations. We sought to identify optimal combinations.

METHODS

We searched PubMed, updated October 2017, using keywords "Breast Neoplasms/drug therapy," "Trastuzumab," and "Clinical Trial" and searched Cochrane Library. Our search included randomized trials of adjuvant H plus chemotherapy for early-stage HER2+ BC, and excluding trials of neoadjuvant therapy or without data to obtain hazard ratios (HRs) for outcomes. Following PRISMA guidelines, one investigator did initial search; two others independently confirmed and extracted information; and consensus with another investigator resolved disagreements. Before gathering data, we set outcomes of overall survival (OS), event-free survival (EFS), and severe cardiac adverse events (SCAEs). Analyzing 6 trials and 13,621 patients, we made direct and indirect comparisons using network meta-analysis on HR for OS or EFS and on odds ratio (OR) for SCAE; ranked therapy was done based on outcomes using p scores.

RESULTS

Compared with anthracycline-cyclophosphamide with taxane (ACT), ACT with concurrent H (ACT+H) showed best OS (HR 0.63, 95% confidence interval [CI] 0.55, 0.72), followed by taxane and carboplatin (TC) with concurrent H (TC+H) (HR 0.77, 95% CI 0.59, 1) and ACT with sequential H (ACT-H) (HR 0.85, 95% CI 0.68, 1.05). Pairwise comparisons showed statistically significant OS benefit for ACT+H over others; similar results for EFS. TC+H showed statistically significant lower SCAE risk compared to ACT+H (OR 0.13, 95% CI 0.03, 0.61).

CONCLUSIONS

Concurrent H with ACT or TC showed most clinical benefit for early-stage HER2+ BC; TC+H had lowest cardiotoxicity.

Effect of a potential probiotics Lactococcus garvieae B301 on the growth performance, immune parameters and caecum microflora of broiler chickens

In this study, a novel Lactococcus garvieae B301 was isolated from the intestinal tract of a healthy piglet. L. garvieae B301 was tolerant to acid pH, simulated gastric and small intestinal transit juices, indicating that it was capable of surviving in the gastrointestinal tract. L. garvieae B301 was safe and beneficial to broilers, as broiler chickens supplemented with L. garvieae B301 had lower diarrhoea incidence and mortality than the Control. Moreover, supplementation of broiler diets with L. garvieae B301 resulted in an increase in body weight and the number of caecum lactic acid bacteria and Bifidobacterium spp., and decrease in feed-to-gain ratio and the number of caecum coliforms. It also had a positive effect on the thymus index and bursa of Fabricius index and enhanced serum levels of immune globulins. All these results showed that L. garvieae B301 could enhance the growth performance of broiler chickens and improve their health. Thus, L. garvieae B301 could be a promising feed additive for broiler chickens.

Serological surveillance for Penicillium marneffei infection in HIV-infected patients during 2004-2011 in Guangzhou, China

Prevalence of disseminated Penicillium marneffei infection is not known in human immunodeficiency virus (HIV)-infected patients. This retrospective study aimed to evaluate the prevalence of and risk factors for disseminated P. marneffei infection in HIV-infected patients during 2004-11 in Guangzhou, China. We tested 8131 archived HIV-infected patient serum samples for P. marneffei-specific mannoprotein (Mp1p) antigen using a highly sensitive and specific ELISA that we previously established. The CD4 count of 2686 cases was determined by flow cytometry. Logistic regression was used to assess predictors of Mp1p antigenaemia. The overall prevalence of disseminated penicilliosis as detected by positive serum Mp1p antigen was 9.36% (761/8131), in good concordance with Platelia™ Aspergillus immunoassay. During 2004-11, the prevalence increased to a peak of 12.58% (158/1256) in 2010 and decreased in 2011. Penicilliosis was strongly associated with progression from HIV to AIDS (OR 4.66, 95% CI 3.94-5.51, p <0.001) and humidity (OR 1.02, 95% CI 1.01-1.03, p 0.002). Disseminated penicilliosis occurred mainly during the rainy seasons (p <0.001). For 2686 cases with known CD4 count, logistic regression showed that CD4 count of <200 cells/μL was a risk factor for penicilliosis (OR 2.90, 95% CI 1.10-7.66, p 0.032), especially when it was <50 cells/μL (OR 24.26, 95% CI 10.63-55.36, p <0.001) during which 28.06% of patients developed disseminated penicilliosis. In conclusion, approximately 9.36% of the HIV-infected patients in our study developed disseminated penicilliosis. Rapid diagnosis may be achieved by performing serological surveillance for Mp1p antigenaemia as a routine procedure for all HIV-infected patients with CD4 count of <50 cells/μL.

Tetraploid complementation proves pluripotency of induced pluripotent stem cells derived from adipose tissue

OBJECTIVES

Recently, pluripotency of induced pluripotent stem (iPS) cells has been displayed after producing adult mice, in tetraploid complementation assays. These studies lead us to the last piece of the puzzle for reprogramming somatic cells into fully pluripotent cells which function as embryonic stem cells in most applications. However, in all of previous studies, skin fibroblasts were used as the starting population for reprogramming, raising questions as to whether the pluripotency of the iPS cells was dependent on the particular starting cell type.

MATERIALS AND METHODS

Our iPS cell lines were prepared from murine adipose stem cells (ASCs). Their multi-potency was first tested by teratoma formation in nude mice. Then, tetraploid complementation was performed to generate progeny from them.

RESULTS

We succeeded to the birth of viable and fertile adult mice derived entirely from reprogrammed ASC, indicating cell types other than fibroblasts can also be restored to the embryonic level of pluripotency.

CONCLUSIONS

We also directed differentiation of iPS cells into chondrocytes, thus adipose-derived iPS cells can be used as models to study chondrogenic differentiation and cartilage regeneration.

Adipogenic differentiation potential of adipose-derived mesenchymal stem cells from ovariectomized mice

OBJECTIVES

In human post-menopausal osteoporosis, enhanced adipogenesis in bone marrow and enhanced formation of adipose tissue in vivo are observed. These changes correlate with reduced trabecular bone volume and increased adipocyte cell size as well as cell number. However, cellular and molecular mechanisms underlying osteoporosis-related changes in adipocyte cell volume are not known. This study was designed to compare adipogenic potential of adipose tissue-derived stem cells (ADSCs) obtained from ovariectomized mice with that of control ADSCs, and to analyse pathological mechanisms from the point of functional changes of ADSCs.

MATERIALS AND METHODS

Healthy female C57BL/6J mice were randomly divided into ovariectomy and sham-surgery groups. Mouse ADSCs were isolated and cultured in vitro up to passage 3. After adipogenic induction, oil red O staining of lipid droplets was used to detect adipogenic ability of ADSCs; real-time PCR and immunofluorescence staining were used to detect expression of adipogenesis-related genes and proteins.

RESULTS

As indicated by increased expression of adipogenic and lipogenic genes and proteins, and lipid droplets accumulation shown by oil red-O staining, adipogenic differentiation of ADSCs was significantly enhanced in the ovariectomy group compared to the sham-surgery group (P < 0.05).

CONCLUSION

These findings suggest that enhanced adipogenic differentiation of ADSCs is likely to be the important cause for increased adipogenesis in vivo and subsequent obesity-like changes in body mass, in mice, after ovariectomy.

Electrospun P34HB fibres: a scaffold for tissue engineering

OBJECTIVES

Amongst the fourth generation of PHAs is bio-plasticpoly3-hydroxybutyrate4-hydroxybutyrate (P34HB); it is thus appropriate to perform novel research on its uses and applications. The main objective of this study was to determine whether electrospun P34HB fibres would accommodate viability, growth and differentiation of mouse adipose-derived stem cells (mASCs).

MATERIALS AND METHODS

In the present study, we looked at P34HB in two forms, electrospun P34HB fibres and P34HB film. Morphology of electrospun P34HB fibres and P34HB film were characterized using scanning electron microscopy, fluorescence microscopy and confocal laser scanning microscopy, after cell seeding. Cell adhesion, proliferation and cytotoxicity tests were conducted on both by MTT and CCK-8 assays, respectively. After being cultured with osteogenic induction, expression of adipogenic genes Runx2, OPN and OCN, were examined by real-time PCR.

RESULTS

By scanning electron microscopy, light microscopy and confocal laser scanning microscopy, we observed that the mASCs grew well associated with the P34HB materials. After MTT and CCK-8 assay, we concluded that P34HB would, indeed, be a material suitable for further cell adhesion and proliferation studies. More importantly, we found that the P34HB matrices promoted expression of Runx2, OPN and OCN with osteogenic induction.

CONCLUSIONS

In this investigation, we can confirm that the electrospun P34HB fibres accommodated survival, proliferation and differentiation of mASCs, and we have been able to draw the conclusion that fibre scaffolds produced by the electrospinning process are promising for application of bone tissue engineering.

Effects of bone morphogenetic protein-4 (BMP-4) on adipocyte differentiation from mouse adipose-derived stem cells

OBJECTIVES

As mesenchymal stem cells (MSCs) can be isolated easily from adipose tissues while retaining their self-renewal and multi-potential differentiation capacities, they hold promising possibilities for being applied extensively in tissue engineering. Bone morphogenetic protein (BMP) family members have been reported to provide instructive signals to MSCs for them to differentiate into several different cell lineages. The study described here aims to investigate whether BMP-4 could promote adipose-derived stem cell (ASC) differentiation into adipocytes under various concentrations.

MATERIALS AND METHODS

ASCs were isolated from mouse inguinal adipose pads and cultured in vitro. 10 ng/ml and 50 ng/ml BMP-4 were added to adipogenic media for 8 days. Oil red-O staining, reverse transcription/polymerase chain reaction and immunocytofluorescence staining were performed to examine differentiation of the ASCs.

RESULTS

As indicated by increased expression of adipogenic and lipogenic genes (PPAR-γ, APN and LPL) and proteins, 50 ng/ml BMP-4 seemed to induce mASCs to differentiate into the adipo-lineage compared to 10 ng/ml BMP-4, and control groups. In addition, lipid droplets accumulated within the adipocytes under 50 ng/ml BMP-4 stimulation, as shown by oil red-O staining.

CONCLUSIONS

Our present study suggests that BMP-4, as an adipo-inducing factor, promoted adipogenesis of ASCs at higher concentrations (50 ng/ml) and can perhaps be considered as a candidate for use in adipose tissue engineering.

Mechanical compressive force inhibits adipogenesis of adipose stem cells

OBJECTIVE

The aim of this study was to investigate effects of mechanical compressive force on differentiation of adipose-derived stem cells (ASCs) in vitro.

MATERIALS AND METHODS

Mice ASCs were treated with compressive force (2000 με, 1 Hz) for 2 or 6 h after adipogenic induction for 3 days, then oil red O staining was used to examine oil droplet-filled cells. Adipogenic genes, PPAR-γ1 and APN, were examined by real-time PCR and immunofluorescence (IF) staining was performed to test expression of de-PPAR-γ and ph-PPAR-γ at the protein level.

RESULTS

Our data showed that mechanical compressive force reduced numbers of oil droplet-filled cells, and down-regulated mRNA levels of both PPAR-γ1 and APN and protein level of PPAR-γ, in ASCs.

CONCLUSIONS

In culture medium containing adipogenic stimuli, mechanical compressive force inhibited adipogenesis of ASCs.

Osteogenic differentiation of adipose-derived stem cells prompted by low-intensity pulsed ultrasound

OBJECTIVES

Based on in vivo studies, low-intensity pulsed ultrasound (LIPUS) stimulation has been widely used in the clinic for advancing bone growth during healing of non-union alignment, fractures and other osseous defects. In this study, we have investigated osteogenic differentiation of adipose stem cells (ASCs) regulated by LIPUS, and also in a preliminarily manner, we have discussed diverse effects of different duty ratio parameters.

MATERIALS AND METHODS

Mouse adipose stem cells were isolated and osteogenically induced. Then they were treated with LIPUS for 10 min/day for 3 days, 5 days and 7 days, respectively. Finally, effects of LIPUS on osteogenic differentiation of the ASCs were analysed by real-time PCR, western blotting and immunofluorescence.

RESULTS

Our data indicated that LIPUS promoted mRNA levels of runt-related transcription factor 2, osteopontin and osterix in the presence of osteo-induction medium; moreover, protein levels of runt-related transcription factor 2 and osteopontin were upregulated.

CONCLUSIONS

We successfully demonstrated that LIPUS enhanced osteogenesis of ASCs, specially at the duty ratio of 20%.

Low-intensity pulsed ultrasound induced enhanced adipogenesis of adipose-derived stem cells

OBJECTIVE

The aim of this study was to investigate effects of low-intensity pulsed ultrasound (LIPUS) on differentiation of adipose-derived stem cells (ASCs), in vitro.

MATERIALS AND METHODS

Murine ASCs were treated with LIPUS for either three or five days, immediately after adipogenic induction, or delayed for 2 days. Expression of adipogenic genes PPAR-γ1, and APN, was examined by real-time PCR. Immunofluorescence (IF) staining was performed to test for PPAR-γ at the protein level.

RESULTS

Our data revealed that specific patterns of LIPUS up-regulated levels of both PPAR-γ1 and APN mRNA, and PPAR-γ protein.

CONCLUSIONS

In culture medium containing adipogenic reagents, LIPUS enhanced ASC adipogenesis.

Characteristics of anaphylaxis-inducing IgG immune complexes triggering murine passive systemic anaphylaxis

BACKGROUND

With the broad and increasing application of therapeutic monoclonal antibodies (mAbs) in clinical settings, IgG-induced allergic reactions, including passive systemic anaphylaxis (PSA), have attracted significant attention. However, it is not clear which types of IgG mAb-antigen complexes or IgG aggregates formed by antigen binding can trigger PSA, as not all immune complexes (ICs) are capable of triggering PSA. Here, we characterise mAb-antigen complexes capable of inducing murine PSA to evaluate and predict which ICs are able to induce PSA.

METHODS

Thirty-six combinatory reactions with eight antigens and 27 corresponding mAbs were used to trigger PSA, which was defined by rectal temperature. Sandwich ELISA, passive cutaneous anaphylaxis (PCA) induction and flow cytometry analysis of CD16/32 (FcγRIII/II) expression were used to characterise the ICs. The dynamic concentrations of antigen in the peripheral blood were measured by ELISA.

RESULTS

Only 14 of the 36 ICs could trigger PSA and thus be termed anaphylaxis-inducing immune complexes (Ai-ICs). The Ai-ICs could be characterised by constructing sandwich ELISA, inducing PCA and down-regulating CD16/32 (FcγRIII/II) expression on blood neutrophils in vitro and in vivo. Additionally, the occurrence and severity of PSA was found to be associated with the instantaneous concentration of antigen in the peripheral blood in the presence of antibody.

CONCLUSIONS

Only Ai-ICs, not all ICs, could trigger IgG-mediated PSA, which could be characterised by the above simple methods. The occurrence and severity of PSA was associated with the instantaneous concentration of antigen in the peripheral blood in the presence of antibody.

Jagged-1-mediated activation of notch signalling induces adipogenesis of adipose-derived stem cells

OBJECTIVES

Notch signalling plays an important role in many cell activities, involving proliferation, migration, differentiation and cell death. The aim of this study was to investigate effects of such signalling on adipogenesis of mouse adipose-derived stem cells (mASCs).

MATERIALS AND METHODS

Jagged1 (50 and 100 ng/ml) was added to mASCs to activate Notch signalling, 2 days before adipogenic induction. At 5 and 7 days after induction, oil red-O staining was performed to evaluate lipid accumulation. Then real-time PCR was performed to examine expression of Notch downstream genes (Notch-1, -2, Hes-1 and Hey-1) and adipogenic transcription factor (PPAR-γ). Expressions of Hes-1 and PPAR-γ at protein level were confirmed by immunofluorescence staining.

RESULTS

Our data indicated that Jagged1 promoted adipogenic differentiation of mASCs. Moreover, Jagged1 also increased expression of Notch downstream genes and PPAR-γ. Expressions of Hes-1 and PPAR-γ were found to be enhanced in Jagged1 pre-treated mASCs when compared to controls.

DISCUSSION

The results led to the conclusion that activation of Notch signalling had stimulated adipogenesis of mASCs in the presence of adipogenic medium by promoting expression of PPAR-γ.

Uniform amorphous lactose microspheres formed in simultaneous convective and dehydration antisolvent precipitation under atmospheric conditions

A simultaneous convection-dehydration and antisolvent precipitation approach has been shown to produce uniform microsized lactose particles from aqueous droplet at atmospheric pressure. Microparticles with high uniformity having diameters of between 1.0 and 2.4 μm have been obtained. The precipitation of the microparticles is driven by a unique self-assembly mechanism that cannot be fully elucidated by supersaturation alone. Further analysis suggests that structural changes in the solvent/antisolvent mixture, due to hydrophobic hydration, could play a role in the precipitation process observed.

Robust Local Search for Solving RCPSP/max with Durational Uncertainty

Scheduling problems in manufacturing, logistics and project management have frequently been modeled using the framework of Resource Constrained Project Scheduling Problems with minimum and maximum time lags (RCPSP/max). Due to the importance of these problems, providing scalable solution schedules for RCPSP/max problems is a topic of extensive research. However, all existing methods for solving RCPSP/max assume that durations of activities are known with certainty, an assumption that does not hold in real world scheduling problems where unexpected external events such as manpower availability, weather changes, etc. lead to delays or advances in completion of activities. Thus, in this paper, our focus is on providing a scalable method for solving RCPSP/max problems with durational uncertainty. To that end, we introduce the robust local search method consisting of three key ideas: (a) Introducing and studying the properties of two decision rule approximations used to compute start times of activities with respect to dynamic realizations of the durational uncertainty; (b) Deriving the expression for robust makespan of an execution strategy based on decision rule approximations; and (c) A robust local search mechanism to efficiently compute activity execution strategies that are robust against durational uncertainty. Furthermore, we also provide enhancements to local search that exploit temporal dependencies between activities. Our experimental results illustrate that robust local search is able to provide robust execution strategies efficiently.

CC chemokine ligand 21 enhances the immunogenicity of the breast cancer cell line MCF-7 upon assistance of TLR2

CC chemokine ligand 21 (CCL21) is a known attractant for CCR7-positive (CCR7+) cells, but its additional role in the immunogenicity of CCR7+ cells remains poorly understood. This study explored the effects of CCL21-CCR7 ligation on cancer immunogenicity and related antitumor immune response, in the presence and absence of mitomycin C (MMC) treatment. CCL21-CCR7 binding upregulated human leukocyte antigen class I-restricted tumor antigen presentation with increased expression of human leukocyte antigen class I and transporter associated with antigen processing-1. In addition, CCL21 restrained the tumor-derived immunosuppressive factors FasL and transforming growth factor-β. Consequently, CCL21 facilitated cancer-educated lymphocytes reaction in vitro. In the tumor-bearing mouse, CCL21 inhibited tumor growth and prolonged mouse survival via lymphocytes, especially in CCR7+ cancer cells. Furthermore, Toll-like receptor 2 activation of lymphocytes assisted the tumor-suppression functions of CCL21, in vitro and in vivo. This study implies that CCL21 improved the immunogenicity of the CCR7+ breast cancer cell line even with MMC treatment and triggered antitumor response by lymphocytes. These findings provide a new insight into the research and application of CCL21-associated antitumor response.

Improvement in reproductive parameters in hypogonadal female mice by regulated gene replacement therapy in the central nervous system

One of the challenges of gene targeting is to achieve regulated transgene expression in specific target cells. The hypogonadal (hpg) mice are genetically deficient in hypothalamic gonadotropin-releasing hormone (GnRH) production due to a deletion in the GnRH gene, resulting in hypogonadotropic hypogonadism. Here we show an improvement in reproductive parameters of adult female homozygous hpg mice by direct infusion into the hypothalamic preoptic area (POA) of a herpes simplex virus (HSV)-based amplicon vector containing a 13.5 kb genomic fragment encoding the GnRH gene together with its cognate promoter and regulatory elements. Following vector injection, GnRH-expressing neurons were detected in the POA, and pituitary and plasma gonadotropin levels as well as ovarian and uterine weights increased. In addition, a subset of injected hpg mice demonstrated cyclic estrous changes, consistent with regulated control of GnRH production. Administration of kisspeptin-10 resulted in an increase in plasma luteinizing hormone levels, further supporting appropriate regulation of the introduced GnRH transgene. These findings indicate that delivery of the GnRH gene resulted in selective neuronal expression of GnRH and regulated hypothalamic GnRH release. To our knowledge, this is the first example of the correct targeting of a gene under its cognate promoter to neurons resulting in selective and regulated synthesis of a biologically active peptide, and thus may have a wide range of applications in the treatment of human disorders.

Engineering and functional evaluation of a single-chain antibody against HIV-1 external glycoprotein gp120

The HIV-1 envelope glycoprotein surface subunit gp120 is an attractive target for molecular intervention. This is because anti-HIV-1 gp120 neutralizing antibodies display the potential ability to inhibit HIV-1 infection. The present investigation describes the construction of a genetically engineered single chain antibody (scFv102) against HIV-1 gp120, its expression and functional evaluation. The parental hybridoma cell line (102) produces an immunoglobulin directed against the conserved CD4-binding region of gp120. cDNAs encoding the variable regions of the heavy (V(H)) and light (V(L)) chains were prepared by reverse transcription PCR and linked together with an oligonucleotide encoding a linker peptide (Gly(4)Ser)(3) to produce a single chain antibody gene. The resulting DNA construct was cloned into a prokaryotic expression vector (pET28) and recombinant scFv102 was expressed in Eserichia coli as an insoluble protein. The denatured scFv102 was refolded and purified by immobilized metal ion affinity chromatography. Purified scFv102 had the same specificity as the intact IgG in immuno-blotting assays and immuno-fluorescence (IF) detection, but ELISA analyses demonstrated the affinity of scFv102 to be 5-fold lower than that of the parental monoclonal antibody. In neutralization assays, scFv102 at concentrations lower than 40 microg/ml exhibited efficient interference with viral replication and inhibition of viral infection (90%) across a range of primary isolates of subtype B HIV-1. These results suggest that the constructed anti-HIV-1 gp120 scFv102 has good biological activity and can potentially be used for in vitro diagnostic and in vivo therapeutic applications.

Soluble member(s) of the mesothelin/megakaryocyte potentiating factor family are detectable in sera from patients with ovarian carcinoma

mAb OV569 was made by immunizing mice with ovarian carcinoma cells. It binds to cells from ovarian carcinomas and, to a lesser extent, to cells from certain other carcinomas whereas the binding to normal tissues is low to nondetectable. It also binds to soluble molecule(s) in culture supernatants from antigen-positive carcinomas. OV569 recognizes a protein(s) of 42-45 kDa with the same N-terminal amino acid sequence as the membrane-bound portion of mesothelin and megakaryocyte potentiating factor (MPF). Binding assays with fusion proteins comprising either the N-terminal part of mesothelin/MPF (D1Ig), reported to be easily cleaved off, or a noncleavable, membrane-associated part (D2Ig) showed that OV569 only binds to D2hIg. A new member of the mesothelin/MPF family was discovered, which has an 82-bp insert in the membrane-associated part, leading to a frameshift of 212 bp, and whose predicted molecular structure indicates that it is soluble. To test patient sera for soluble tumor antigen, antigen was isolated from cell-free tumor culture supernatants via immunoadsorption with OV569 and used to generate murine mAbs to an epitope different from the one to which OV569 binds, after which mAbs to two different epitopes were used to develop a "sandwich ELISA." Using this assay, the level of circulating antigen was elevated significantly in 23 of 30 sera from patients with ovarian carcinoma, as compared with 0 of 68 sera from healthy controls, 0 of 3 sera from patients with nonneoplastic diseases, and 25 of 75 sera from patients with other tumors. Soluble molecules of the mesothelin/MPF family may provide useful new marker(s) for diagnosis of ovarian carcinoma and/or monitoring its response to therapy.

[Anti-promoting and anti-mutagenic actions of G9315]

G9315, a complex extracted from Glycyrrhizae inflata Bat (III), consists of 6 flavonoids with significant antioxidant effects. At 1 mg dose it inhibited the mouse ear edema induced by croton oil, and showed strong anti-promoting effects on two-stage carcinogenesis in mouse skin induced by DMBA plus croton oil. The TPA enhanced 32Pi-incorporation into phospholipid fraction in HeLa cells was inhibited, and the micronuclei in mouse bone marrow cells induced by cytoxan was also depressed.

[Antioxidant action of garlic oil and allitridi]

The lipid peroxidation and chemiluminescence (CL) of mouse liver mitochondria induced by a Vc/FeSO4 reaction system was greatly inhibited by garlic oil (GO) and allitridi (Alt) at 0.1 mg/ml. HpD-induced photohemolysis was moderately inhibited by garlic oil (25 micrograms/ml) and allitridi (20 micrograms/ml). Allitridi (200 micrograms/ml) effectively prevented inactivation of red cell membrane acetylcholine sterase (AchEs) caused by .OH, and at 250 micrograms/ml it markedly inhibited blood CL stimulated by croton oil. Garlic oil (5 micrograms/ml) and allitridi (100 micrograms/ml) significantly increased O2-. production. Allitridi at 0.25 mg/ml and 1 mg/ml enhanced lipid peroxidation of mitochondria and blood CL caused by H2O2.

[Protective effect of tannic acid against TPA- and cigarette smoke condensate-induced DNA strand breaks in human white cells and its antioxidant action]

Tannic acid was extracted from Rhus chinensis Mill. At a concentration of 50 micrograms/ml it could significantly prevent the DNA damaging effects induced by TPA (100 ng/ml) or cigarette smoke condensate (400 micrograms/ml). At concentrations of 5 micrograms/ml and 80 micrograms/ml, it could effectively scavenge the O2-. produced by VB2 + hv and cigarette smoke condensate, respectively. The lipid peroxidation of red cell membrane induced by H2O2 was decreased significantly by tannic acid at a concentration of 5 micrograms/ml.