Effects of human umbilical cord serum on proliferation and insulin content of human fetal islet-like cell clusters

BACKGROUND: Type 1 diabets is an autoimmune disease caused by the destruction of pancreatic β-cell with an in- creased incidence worldwide in the closing decades of the 20th century. This study was to investigate the effects of human umbilical cord serum (UCS) on the proliferation and function of human fetal islet-like cell clusters (ICCs) in vitro. METHODS: Eight fresh pancreatic glands obtained after in- duction of labor with water bag were mildly exposed to col- lagenase V, and the digested cells were cultured in a RPMI- 1640 medium plus 10% pooled UCS or fetal calf serum (FCS) to permit cells attachment and outgrowth of ICCs. RESULTS: In 8 consecutively explanted glands, develop- ment and proliferation of ICCs were observed. In the pre- sence of FCS, the outgrowth of ICC took place on the top of a flbroblast monocellular layer. UCS affected less growth of fibroblasts and increased the formation of ICCs about four-fold compared with explants from the same glands maintained in FCS. In both UCS and FCS, the insulin con- tent of the medium was variable to a certain extent and progressively declined from day 2 to day 6. Dithizone- stained ICCs in UCS suggested that most cell clusters were islet cells ( β-cells), and the purity of islets was estimated 80%-90%. The ultrastructure of the cultured cells showed a large number of granule-containing cells, most of which were identified as β-cells. CONCLUSION: We conclude that in comparison with ex- plants with FCS, the yield of ICCs and purification of islet cells are markedly increased by UCS and may facilitate the proliferation of pancreatic β-cells intended for islet trans- plantation.

Differentiation of fetal pancreatic stem cells into neuron-like and islet-like cells in vitro

Pancreatic stem cells were isolated and cultured from aborted human fetal pancreases of gestational age 14-20 weeks. They were seeded at a density of 1 × 104 in serum-free media for differentiation into neuron-like cells, expressing β-tubulin III and glial fibrillary acidic protein. These neuron-like cells displayed a synapse-like morphology and appeared to form a neuronal network. Pancreatic stem cells were also seeded at a density of 1 × 105 for differentiation into islet-like cells, expressing insulin and glucagon, with an islet-like morphology. These cells had glucose-stimulated secretion of human insulin and C-peptide. Results suggest that pancreatic stem cells can be differentiated into neuron-like and islet-like cells.

Advanced Coverage Optimization Techniques for Small Cell Clusters

Coverage challenge for small considered to be a optlmlzation is a main cell clusters which are promising solution to provide seamless cellular coverage for large indoor or outdoor areas. This paper focuses on small cell cluster coverage problems and proposes both centralized and distributed self-optimization methods. Modified Particle swarm optimization （MPSO） is introduced to centralized optimization which employs particle swarm optimization （PSO） and introduces a heuristic power control scheme to accelerate the algorithm to search tbr the global optimum solution. Distributed coverage optimization is modeled as a non-cooperative game, with a utility function considering both throughput and interference. An iterative power control algorithm is then proposed using game theory （DGT） which converges to Nash Equilibrium （NE）. Simulation results show that both MPSO and DGT have excellent performance in coverage optimization and outperform optimization using simulated annealing algorithm （SA）, reaching higher coverage ratio and throughput while with less iterations.

Photocurrent improvement of an ultra-thin silicon solar cell using the localized surface plasmonic effect of clustering nanoparticles

The cluster-shaped plasmonic nanostructures are used to manage the incident light inside an ultra-thin silicon solar cell.Here we simulate spherical,conical,pyramidal,and cylindrical nanoparticles in a form of a cluster at the rear side of a thin silicon cell,using the finite difference time domain(FDTD)method.By calculating the optical absorption and hence the photocurrent,it is shown that the clustering of nanoparticles significantly improves them.The photocurrent enhancement is the result of the plasmonic effects of clustering the nanoparticles.For comparison,first a cell with a single nanoparticle at the rear side is evaluated.Then four smaller nanoparticles are put around it to make a cluster.The photocurrents of 20.478 mA/cm2,23.186 mA/cm2,21.427 mA/cm2,and 21.243 mA/cm2 are obtained for the cells using clustering conical,spherical,pyramidal,cylindrical NPs at the backside,respectively.These values are 13.987 mA/cm2,16.901 mA/cm2,16.507 mA/cm2,17.926 mA/cm2 for the cell with one conical,spherical,pyramidal,cylindrical NPs at the backside,respectively.Therefore,clustering can significantly improve the photocurrents.Finally,the distribution of the electric field and the generation rate for the proposed structures are calculated.

Iron Atom-Cluster Strategy Synthesis of Hierarchically Porous Fe-N-C Catalysts for Proton Exchange Membrane Fuel Cells

Developing nonprecious metal-nitrogen-doped carbon(M-N-C)catalysts with high activity and stability is critical to their widespread use in fuel cells;however,these catalysts still face considerable challenges.Herein,a novel iron atom-cluster strategy for the synthesis of iron-based N-C catalyst comprising Fe nanoparticles(Fe NPs)surrounded by Fe-N_(x) sites is developed for oxygen reduction reactions in an acidic fuel cell.Iron oxide NPs were incorporated into zeolitic imidazolate framework-8(ZIF-8)-derived carbon materials and pyrolyzed at high temperatures using NaCl as a modifi er to produce Fe NPs and Fe-N_(x) composite active sites.The half-wave potential of the optimized Fe_(NP)/FeNC-NaCl material was substantially improved to 0.81 V.Furthermore,even after 15,000 cycles,the half-wave potential of the catalyst remained essentially unchanged.As a cathode catalyst for fuel cells,it realized a high peak power density of 436 mW/cm^(2)under a practical H_(2)-air atmosphere.Therefore,this study presents a new approach for designing and synthesizing electrocatalytic materials with high catalytic activity and stability.

Differentiation of Pancreatic Ductal Epithelial Cells into Insulin Like Cell Clusters in Chronic Pancreatitis

Background/Aim: Islet regeneration in chronic pancreatitis (CP) is relevant for managing the associated loss of endocrine function. Because ductal epithelial cells were earlier demonstrated to differentiate into pancreatic endocrine mass, we evaluated their proliferation and differentiation in chronic pancreatitis. Methods: Pancreatic ducts were obtained from surgically resected pancreata of 12 patients with chronic pancreatitis and 15 control subjects. CK19 positive ductal cells were evaluated for their proliferating and differentiating abilities upon immunostaining with Ki 67 and hormone positivity for insulin and glucagon, apart from monitoring Pdx 1 expression. Results: In comparison to the controls, a greater number of proliferating pancreatic ductal epithelial cells (PDECs) were observed under conditions of CP. The increase in Pdx1 expressing PDECs (22%) and proliferating Pdx1 expressing PDECs (30%) was significant (P < 0.04). Number of cells expressing insulin/glucagon in the exocrine ducts increased significantly in CP as compared to controls (P ?β?cell mass adjacent to the ducts increased by 28%.?Conclusion: Enhanced capability of PDECs to proliferate and differentiate into endocrine mass suggests that PDECs form a source of progenitors for cell based therapy in chronic pancreatitis.

Theoretical Study on Electronic, Optical, and Charge Transfer Properties of Starburst Triphenylamine as Sensibilizer @TiO2 Cluster for Dye-sensitized Solar Cells

Here, a series of starburst triphenylamine(WD8) derivatives for dye-sensitized solar cells(DSSCs) applications have been designed. The frontier molecular orbitals(FMOs) property, absorption spectra, and charge transfer rate property of WD8 and its derivatives were simulated. We also evaluated the FMOs energies and absorption spectra of WD8 and its derivatives with the TiO2 cluster. The simulation results show that the phenothiazine-triphenylamine and 2-cyanoacetic acid groups in the ortho-position will increase the HOMO energy, decrease the LUMO energy, and narrow the HOMO-LUMO gap of WD8. The charge injection from WD8 and its derivatives to TiO2 should be more favorable. The phenothiazine-triphenylamine and 2-cyanoacetic acid groups in the ortho-position will decrease the electron and hole injection barriers of WD8. The phenothiazinetriphenylamine and 2-cyanoacetic acid groups in the ortho-position will improve the absorption spectra properties of WD8. The absorption spectra of WD8 and its derivatives with the TiO2 cluster would have a red shift. The phenothiazine-triphenylamine and 2-cyanoacetic acid groups in the ortho-position will increase the charge transfer property of WD8.

Directional-to-random transition of cell cluster migration

Efficient cell migration is crucial for the functioning of biological processes, e.g., morphogenesis, wound healing, and cancer metastasis. In this study, we monitor the migratory behavior of the 3D fibroblast clusters using live cell microscopy,and find that crowded environment affects cell migration, i.e., crowding leads to directional migration at the cluster’s periphery. The number of cell layers being stacked during seeding determines the directional-to-random transition. Intriguingly,the migratory behavior of cell clusters resembles the dispersion dynamics of clouds of passive particles, indicating that the biological process is driven by physical effects(e.g., entropy) rather than cell communication. Our findings highlight the role of intrinsic physical characteristics, such as crowding, in regulating biological behavior, and suggest new therapeutic approaches targeting at cancer metastasis.

Effects of EMS Treatments on Multiplication and Differentiation of Sugarcane Embryonic Cell Clusters

[ Objective] This study aimed to investigate the effects of EMS （ethyl methane sulfonate） treatments on multiplication and differentiation of sugarcane embryonic cell clusters. [ Method] Sugarcane variety Xintaitang 22 （ROC22） was used as the experimental material. After treated with different concentrations of EMS for different time, sugarcane embryonic cell clusters were collected for subculture, differentiation and rooting, to compare and analyze the correlation of differ- ent EMS treatments with the muhiplicafion and differentiation of sugarcane embryonic cell clusters. [ Result] Treating ROC22 embryonic cell clusters with 0. 10% -0.15% EMS for4-6 h led to the best results, which reached the level of semi-lethal dose. Sugarcane embryonic cell clusters treated with EMS were adopted for subculture; results indicated that browning rate of cell clusters was higher than that in control （CK） but embryonic structure proportion was lower than that in control ; in addition, multiplication multiple of sugarcane embryonic cell clusters was also lower than that in control. After treated with EMS, sugarcane em- bryonic cell clusters exhibited significantly lower bud differentiation rate and higher browning rate compared with control. Furthermore, treating sugarcane embryonic cell clusters with 0.15% EMS for 2 h was conducive to plantlet emergence and rooting of sugarcane embryonic cell clusters. [ Conclusion] This study provided the- oretical basis for effective mutagenesis of sugarcane using EMS.

Synthesis of Ag/Ag₂S Nanoclusters Resistive Switches for Memory Cells

Resistive switching Ag/Ag2S nanoclusters were formed by sulphidation of melting-dispersed thin and continuous Ag films. The morphology, structure and electrical properties of the prepared clusters were characterized by scanning (SEM), transmitting electron (TEM), scanning resistance microscopes (SRM) and Raman scattering. Hysteretic resistive switching behavior was observed in the samples that were studied with ON/OFF switching voltage equal to 8 - 10 V respectively. Simple empirical numerical simulation model, based on Deal-Grove model assumptions and mechanisms, for silver nanoclusters sulphidation process, was proposed.

Algorithm to identify circulating tumor cell clusters using in vivo flow cytometer

Recent studies in oncology have addressed the importance of detecting circulating tumor cell clusters because circulating tumor cell clusters might survive and metastasize more easily than single circulating tumor cells.Signals with larger peak widths detected by in vivo flow cytometer(IVFC)have been used to identify cell clusters in previous studies.However,the accuracy of this criterion might be greatly degraded by variance in blood°ow and the rolling behaviors of circulating tumor cells.Here,we propose a criterion and algorithm to distinguish cell clusters from single cells.In this work,we first used area-based and volume-based models for single°uorescent cells.Simulating each model,we analyzed the corresponding morphology of IVFC signals from cell clusters.According to the Rayleigh criterion,the valley between two adjacent peak signals from two distinguishable cells should be lower than 73.5%of the peak values.A novel signal processing algorithm for IVFC was developed based on this criterion.The results showed that cell clusters can be reliably identied using our proposed algorithm.Intravital imaging was also performed to further support our algorithm.With enhanced accuracy,IVFC is a powerful tool to study circulating cell clusters.

Experiment on inducing apoptosis of melanoma cells by micro-plasma jet

As a promising cancer treatment method,cold atmospheric plasma has received widespread attention in recent years.However,previous research has focused more on how to realize and expand the anti-cancer scope of plasma jet.There are also studies on the killing of small-scale cancer cells,but the effects of plasma jet on normal cells and normal cell clusters have been ignored.Therefore,we proposed a 50μm sized micro-plasma jet device,and used the device to treat melanoma cells(A-375)and human glial cells(HA1800)to evaluate their anti-cancer effects and effects on normal cells.The experimental results show that this kind of micro-plasma jet device can effectively inactivate cancer cells in a short period of time,while having little effect on normal cells.This work provides a certain experimental basis for the application offine plasma jet to clinically inactivate cancer cells.

Direct Differentiation of Plants from Small Cell Clusters of Indica Rice in Suspension Culture

The major factors affecting plant regeneration in suspension culture were investigated.The resultsshow that,in order for cell clusters to differentiate directly in liquid medium,it is essential toestablish an embryogenic callus line with high potential for plant regeneration.Embryogenic calliwere suspended in AA basic medium supplemented with 2,4-D 1 mg/L,6-benzylaminopurine 0.5mg/L,CH 300 mg/L,sucrose 3％ and mannitol 3％ and subcultured 7 days for each passage.Aftermore than 6 months of culturing,a fine suspension culture of small cell clusters(SCC)wasestablished.The SCC,80-270μin diameter,were then transferred to a liquid medium(MSsupplemented with NAA 0.01 mg/L and 4-pyridylurae(4-PU)0.5 mg/L)and allowed to grow instationary culture.Finally direct differentiation from SCC was observed.Several factors in suspension-subculture exerted strong after-effects on differentiation ofSCC.Basicmedia,kinds and concentration combinations of auxin and cytokinin in the subculture media,duration of shaking at each subculture passage,and amount of packed cell volume transferred to newmedium at each subculture passage and so on,all these affected the frequency of differentiation ofSCC.Higher concentrations of NAA and kinetin in the differentiation medium inhibited the directdifferentiation of SCC.Low concentrations(0.01-0.1 mg/L)of NAA with 4-PU in thedifferentiation medium were helpful for the direct differentiation of SCC.The differentiated clusterspossessed typical embryogenic structure from which normal plantlets could develop after transferringto agar medium.

基于2018-2022年国家自然科学基金结题项目分析干细胞研究现状

背景:目前大多数研究从国家自然科学基金资助论文和项目申请角度出发,对干细胞某一方面进行深入分析,或者验证某种评价方法,缺乏对干细胞领域国家自然科学基金已结题项目的全面分析。目的:了解2018-2022年干细胞领域国家自然科学基金结题项目资助情况及研究热点,为后续研究提供参考。

Supragel-mediated efficient generation of pancreatic progenitor clusters and functional glucose-responsive islet-like clusters

Although several synthetic hydrogels with defined stiffness have been developed to facilitate the proliferation and maintenance of human pluripotent stem cells(hPSCs),the influence of biochemical cues in lineage-specific differentiation and functional cluster formation has been rarely reported.Here,we present the application of Supragel,a supramolecular hydrogel formed by synthesized biotinylated peptides,for islet-like cluster differentiation.We observed that Supragel,with a peptide concentration of 5 mg/mL promoted spontaneous hPSCs formation into uniform clusters,which is mainly attributable to a supporting stiffness of∼1.5 kPa as provided by the Supragel matrix.Supragel was also found to interact with the hPSCs and facilitate endodermal and subsequent insulin-secreting cell differentiation,partially through its components:the sequences of RGD and YIGSR that interacts with cell membrane molecules of integrin receptor.Compared to Matrigel and suspension culturing conditions,more efficient differentiation of the hPSCs was also observed at the stages 3 and 4,as well as the final stage toward generation of insulin-secreting cells.This could be explained by 1)suitable average size of the hPSCs clusters cultured on Supragel;2)appropriate level of cell adhesive sites provided by Supragel during differentiation.It is worth noting that the Supragel culture system was more tolerance in terms of the initial seeding densities and less demanding,since a standard static cell culture condition was sufficient for the entire differentiation process.Our observations demonstrate a positive role of Supragel for hPSCs differentiation into islet-like cells,with additional potential in facilitating germ layer differentiation.

Daily genetic profiling indicates JAK/STAT signaling promotes early hepatic stellate cell transdifferentiation

AIM: To identify signaling pathways and genes that initiate and commit hepatic stellate cells (HSCs) to transdifferentiation. METHODS: Primary HSCs were isolated from male Sprague-Dawley rats and cultured on plastic for 0-10 d. Gene expression was assessed daily (quiescent to day 10 culture-activation) by real time polymerase chain reaction and data clustered using AMADA software. The significance of JAK/STAT signaling to HSC transdifferentiation was determined by treating cells with a JAK2 inhibitor. RESULTS: Genetic cluster analyses, based on expression of these 21 genes, showed similar expression profiles on days 1-3, days 5 and 6, and days 7-10, while freshly isolated cells (day Q) and day 4 cells were genotypically distinct from any of the other days. Additionally, gene expression clustering revealed strong upregulation of interleukin-6, JAK2 and STAT3 mRNA in the early stages of activation. Inhibition of the JAK/STAT signaling pathway impeded the morphological transdifferentiation of HSCs which correlated with decreased mRNA expression of several profibrotic genes including collagens, α-SMA, PDGFR and TGFβR. CONCLUSION: These data demonstrate unique clustered genetic profiles during the daily progression of HSC transdifferentiation and that JAK/STAT signaling may be critical in the early stages of transdifferentiation.

Expression of cell adhesion molecule CD44 in gastric adenocarcinoma and its prognostic importance

AIM: To evaluate the relation of cluster of differentiation 44 (CD44) expression with clinicopathological features of gastric adenocarcinoma, and also its effect on prognosis with an emphasis on the differences between intestinal and diffuse types. METHODS: From 2000 to 2006, 100 patients with gastric adenocarcinoma, who had undergone total or subtotal gastrectomy without any prior treatment, were studied. Haematoxylin & eosin (HE) staining was used for histological evaluation, including the type (Lauren's classifi cation) and grading of the tumor. The expression of CD44 in the gastric adenocarcinoma mucosa and the adjacent mucosa were determined by immunohistochemistry. The survival analysis was obtained using the Kaplan-Meier test. RESULTS: Of 100 patients, 74 (74%) patients were male. The tumors were categorized as intestinal type (78%) or diffuse type (22%). Sixty-five percent of patients were CD44-positive. CD44 expression was not detected in normal gastric mucosa. Rather, CD44 was more commonly expressed in the intestinal subtype (P = 0.002). A signifi cant relation was seen between the grade of tumor and the expression of CD44 (P = 0.014). The survival analysis showed a poor prognosis of patients with CD44-positive tumors (P = 0.008); and this was more prominent in the intestinal (P = 0.001) rather than diffuse type. CONCLUSION: Cell adhesion molecule CD44 is highly expressed in gastric adenocarcinoma. CD44 expression is correlated with a poor prognosis in patients with the intestinal type of gastric adenocarcinoma. CD44 can, therefore, be utilized as a prognostic marker for this group of patients.

Output Tracking Control of a Hydrogen-air PEM Fuel Cell

Hydrogen-air proton exchange membrane U+0028 PEM U+0029 fuel cell is a promising clean energy. However, the stack output tracking control is still a challenging problem due to the soft characteristic of the stack. Both over- and less-control will cause the stack flooding or oxygen lacking which dramatically decreases the life of stacks. Traditional control methods rely on the accurate model of the fuel cell system, which is a high-order nonlinear system, and involve a complex controller design process. This paper combines the data-based fuzzy cluster modeling technology with the sliding mode control and the integral actions. The sliding mode controller tracks the dynamic changes of the fuel cell system and the integral controller eliminates the steady-state errors. Simulation results demonstrate good performance of the proposed control method. © 2017 Chinese Association of Automation.

Clustered Regularly Interspaced Short Palindromic Repeats(CRISPR):A critical overview on the most promising applications of molecular scissors in oral medicine

The scientific community is continuously working to translate the novel biomedical techniques into effective medical treatments.CRISPR-Cas9 system(Clustered Regularly Interspaced Short Palindromic Repeats-9),commonly known as the“molecular scissor”,represents a recently developed biotechnology able to improve the quality and the efficacy of traditional treatments,related to several human diseases,such as chronic diseases,neurodegenerative pathologies and,interestingly,oral diseases.Of course,dental medicine has notably increased the use of biotechnologies to ensure modern and conservative approaches:in this landscape,the use of CRISPR-Cas9 system may speed and personalize the traditional therapies,ensuring a good predictability of clinical results.The aim of this critical overview is to provide evidence on CRISPR efficacy,taking into specific account its applications in oral medicine.

Combination of CRISPR/Cas9 System and CAR-T Cell Therapy:A New Era for Refractory and Relapsed Hematological Malignancies

Chimeric antigen receptor T(CAR-T)cell therapy is the novel treatment strategy for hematological malignancies such as acute lymphoblastic leukemia(ALL),lymphoma and multiple myeloma.However,treatment-related toxicities such as cytokine release syndrome(CRS)and immune effector cell-associated neurotoxicity syndrome(ICANS)have become significant hurdles to CAR-T treatment.Multiple strategies were established to alter the CAR structure on the genomic level to improve efficacy and reduce toxicities.Recently,the innovative gene-editing technology-clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated nuclease9(Cas9)system,which particularly exhibits preponderance in knock-in and knockout at specific sites,is widely utilized to manufacture CAR-T products.The application of CRISPR/Cas9 to CAR-T cell therapy has shown promising clinical results with minimal toxicity.In this review,we summarized the past achievements of CRISPR/Cas9 in CAR-T therapy and focused on the potential CAR-T targets.