Biomechanical analysis of an osteocyte model by considering bone matrix’s piezoelectricity

Osteocytes,the primary cells in bone,play a crucial role in sensing external load environments and regulating other bone cells.Due to the piezoelectric effect of the mineralized matrix and collagen that make up bone,the mechanical stimulus received is converted into an electrical stimulus to affect the reconstruction of bone.Despite the importance of osteocyte,many studies have focused on the mechanical loading and fluid flow of it,there is still a gap in the study of the piezoelectric effects of various mechanosensors on the microscale.In this paper,we developed a finite element model of osteocytes that incorporates the piezoelectric bone matrix.This model is comprehensive,comprising the osteocyte cell body enclosed by lacuna,osteocyte processes enclosed by canaliculi,and the interposed charged ionic fluid.Additionally,it features mechanosensors such as collagen hillocks and primary cilia.In our study,we subjected the piezoelectric bone matrix model to triaxial displacement,subsequently assessing the electrical signal variations across different mechanosensors within the osteocyte.The observed disparities in mechanical perception by various mechanosensors were primarily attributable to greater liquid velocity changes in the polarization direction as opposed to other directions.Collagen hillocks showed insensitivity to piezoelectric signals,serving predominantly to mechanically transmit signals through solid-to-solid contact.In contrast,processes and primary cilia were highly responsive to piezoelectric signals.Interestingly,the processes oriented in the direction of the electric field demonstrated a differential piezoelectric signal perception compared to those in other directions.Primary cilia were especially sensitive to fluid flow pressure changes,which were influenced both by loading rates and external piezoelectric effects.Overall,our findings illuminate the complexity of mechanical perception within osteocytes in a piezoelectric environment.This adds a new dimension to our understanding and suggests avenues for future research in bone reconstruction and cellular mechanical behavioral transmission.

Prospects for the therapeutic development of umbilical cord bloodderived mesenchymal stem cells

Umbilical cord blood(UCB)is a primitive and abundant source of mesenchymal stem cells(MSCs).UCB-derived MSCs have a broad and efficient therapeutic capacity to treat various diseases and disorders.Despite the high latent selfrenewal and differentiation capacity of these cells,the safety,efficacy,and yield of MSCs expanded for ex vivo clinical applications remains a concern.However,immunomodulatory effects have emerged in various disease models,exhibiting specific mechanisms of action,such as cell migration and homing,angiogenesis,anti-apoptosis,proliferation,anti-cancer,anti-fibrosis,anti-inflammation and tissue regeneration.Herein,we review the current literature pertaining to the UCB-derived MSC application as potential treatment strategies,and discuss the concerns regarding the safety and mass production issues in future applications.

Recent advances of flexible perovskite solar cells

In few years only, the efficiency record of perovskite solar cells（PSCs） has raised quickly from 3.8% to over 22%. This emerging photovoltaic technology has primarily shown its great potential of industrialization. Flexible PSCs are thought to be one of the most priority options for mass production, related to the intrinsic advantage of perovskite thin films which could be deposited by facile solution processes at low temperature. Flexible PSCs have at least four advantages in comparison to the rigid counterpart：（1） it can generate higher power output at lighter weight,（2） it is easily portable,（3） it can be easily attached to architectures or textiles with diverse shapes, and（4） it is compatible with roll-to-roll fabrication in a large scale. In this review, we have summarized recent development of the key materials and technologies applied in flexible PSCs. The key materials including flexible substrates, transparent and conductive electrodes, and interfacial materials; some key technologies about roll-to-roll manufacture, encapsulation technology have been overviewed. Finally, a prospect on possible application directions of flexible PSCs has been discussed.

CFD simulation of effect of anode configuration on gas–liquid flow and alumina transport process in an aluminum reduction cell

Numerical simulations of gas–liquid two-phase flow and alumina transport process in an aluminum reduction cell were conducted to investigate the effects of anode configurations on the bath flow, gas volume fraction and alumina content distributions. An Euler–Euler two-fluid model was employed coupled with a species transport equation for alumina content. Three different anode configurations such as anode without a slot, anode with a longitudinal slot and anode with a transversal slot were studied in the simulation. The simulation results clearly show that the slots can reduce the bath velocity and promote the releasing of the anode gas, but can not contribute to the uniformity of the alumina content. Comparisons of the effects between the longitudinal and transversal slots indicate that the longitudinal slot is better in terms of gas–liquid flow but is disadvantageous for alumina mixing and transport process due to a decrease of anode gas under the anode bottom surface. It is demonstrated from the simulations that the mixing and transfer characteristics of alumina are controlled to great extent by the anode gas forces while the electromagnetic forces(EMFs) play the second role.

Epigenome-Metabolome-Epigenome signaling cascade in cell biological processes

Cell fate determination as a fundamental question in cell biology has been extensively studied at different regulatory levels for many years.However,the mechanisms of multilevel regulation of cell fate determination remain unclear.Recently,we have proposed an Epigenome-Metabolome-Epigenome(E-M-E)signaling cascade model to describe the cross-over cooperation during mouse somatic cell reprogramming.In this review,we summarize the broad roles of E-M-E signaling cascade in different cell biological processes,including cell differentiation and dedifferentiation,cell specialization,cell proliferation,and cell pathologic processes.Precise E-M-E signaling cascades are critical in these cell biological processes,and it is of worth to explore each step of E-M-E signaling cascade.E-M-E signaling cascade model sheds light on and may open a window to explore the mechanisms of multilevel regulation of cell biological processes.

Process engineering in electrochemical energy devices innovation

This review focuses on the application of process engineering in electrochemical energy conversion and storage devices innovation. For polymer electrolyte based devices, it highlights that a strategic simple switch from proton exchange membranes(PEMs) to hydroxide exchange membranes(HEMs) may lead to a new-generation of affordable electrochemical energy devices including fuel cells, electrolyzers, and solar hydrogen generators. For lithium-ion batteries, a series of advancements in design and chemistry are required for electric vehicle and energy storage applications. Manufacturing process development and optimization of the LiF eP O_4/C cathode materials and several emerging novel anode materials are also discussed using the authors' work as examples.Design and manufacturing process of lithium-ion battery electrodes are introduced in detail, and modeling and optimization of large-scale lithium-ion batteries are also presented. Electrochemical energy materials and device innovations can be further prompted by better understanding of the fundamental transport phenomena involved in unit operations.

Over 9% efficiency achieved for all-polymer solar cells processed by a green solvent

Bulk-heterojunction polymer solar cells （PSCs） have at- tracted considerable attention owning to their potential for fabricating flexible, light-weight and large area solar cell panels via high-throughput roll-to-roll technologies. Compared with conventional PSCs comprising small mol- ecule acceptors, such as fullerenes, all-polymer solar cells （all-PSCs） containing blends of p-type/n-type polymers in the photoactive layer provide advantages including easily tunable absorption band, enhanced absorption coefficient,

Interfacial engineering of printable bottom back metal electrodes for full-solution processed flexible organic solar cells

Printing of metal bottom back electrodes of flexible organic solar cells（FOSCs） at low temperature is of great significance to realize the full-solution fabrication technology. However, this has been difficult to achieve because often the interfacial properties of those printed electrodes, including conductivity, roughness, work function,optical and mechanical flexibility, cannot meet the device requirement at the same time. In this work, we fabricate printed Ag and Cu bottom back cathodes by a low-temperature solution technique named polymer-assisted metal deposition（PAMD） on flexible PET substrates. Branched polyethylenimine（PEI） and ZnO thin films are used as the interface modification layers（IMLs） of these cathodes. Detailed experimental studies on the electrical, mechanical, and morphological properties, and simulation study on the optical properties of these IMLs are carried out to understand and optimize the interface of printed cathodes. We demonstrate that the highest power conversion efficiency over 3.0% can be achieved from a full-solution processed OFSC with the device structure being PAMDAg/PEI/P3 HT：PC61BM/PH1000. This device also acquires remarkable stability upon repeating bending tests.

Electron transport layer driven to improve the open-circuit voltage of CH_3NH_3PbI_3 planar perovskite solar cells

Suitable electron transport layers are essential for high performance planar perovskite heterojunction solar cells. Here, we use ZnO electron transport layer sputtered under oxygen-rich atmosphere at room temperature to decrease the hydroxide and then suppress decomposition of perovskite films. The perovskite films with improved crystallinity and morphology are achieved. Besides, on the ZnO substrate fabricated at oxygen-rich atmosphere, open-circuit voltage of the CH_3NH_3PbI_3-based perovskite solar cells increased by 0.13 V.A high open-circuit voltage of 1.16 V provides a good prospect for the perovskite-based tandem solar cells. The ZnO sputtered at room temperature can be easily fabricated industrially on a large scale, therefore, compatible to flexible and tandem devices. Those properties make the sputtered ZnO films promising as electron transport materials for perovskite solar cells.

Real time monitoring of bioreactor mAb IgG3 cell culture process dynamics via Fourier transform infrared spectroscopy： Implications for enabling cell culture process analytical technology

Compared to small molecule process analytical technology （PAT） applications, biotechnology product PAT applications have certain unique challenges and opportunities. Understanding process dynamics of bioreactor cell culture process is essential to establish an appropriate process control strategy for biotechnology product PAT applications. Inline spectroscopic techniques for real time monitoring of bioreactor cell culture process have the distinct potential to develop PAT approaches in manufac- turing biotechnology drug products. However, the use of inline Fourier transform infrared （FTIR） spectroscopic techniques for bioreactor cell culture process monitoring has not been reported. In this work, real time inline FTIR Spectroscopy was applied to a lab scale bioreactor mAb IgG3 cell culture fluid biomolecular dynamic model. The technical feasibility of using FTIR Spectroscopy for real time tracking and monitoring four key cell culture metabolites （including glucose, glutamine, lactate, and ammonia） and protein yield at increasing levels of complexity （simple binary system, fully formulated media, actual bioreactor cell culture process） was evaluated via a stepwise approach. The FTIR fingerprints of the key metabolites were identified. The multivariate partial least squares （PLS） calibration models were established to correlate the process FTIR spectra with the concentrations of key metabolites and protein yield of in-process samples, either individually for each metabolite and protein or globally for all four metabolites simultaneously. Applying the 2＇ld derivative pre-processing algorithm to the FTIR spectra helps to reduce the number of PLS latent variables needed significantly and thus simplify the interpretation of the PLS models. The validated PLS models show promise in predicting the concentration profiles of glucose, glutamine, lactate, and ammonia and protein yield over the course of the bioreactor cell culture process. Therefore, this work demonstrated the technical feasibility of real time monitoring of the bioreactor cell culture process via FTIR spectroscopy. Its implications for enabling cell culture PAT were discussed.

Efficient perovskite solar cells based on the novel low-temperature processed electron transport layer

With the support by the National Natural Science Foundation of China,the research team led by Prof.Hou Yu(侯宇)and Prof.Yang Huagui(杨化桂)at the Key Laboratory for Ultrafine Materials of Ministry of Education,School of Materials Science and Engineering,East China University of Science

A putative plant organelle RNA recognition protein gene is essential for maize kernel development

Basal endosperm transfer layer（BETL） cells are responsible for transferring apoplastic solutes from the maternal pedicel into the endosperm,supplying the grain with compounds required for embryo development and storage reserve accumulation.Here,we analyze the maize（Zea mays L.） empty pericarp6（emp6） mutant,which causes early arrest in grain development.The Emp6 tgene function is required independently in both the embryo and endosperm.The emp6 mutant causes a notable effect on the differentiation of BETL cells;the extensive cell wall ingrowths that distinguish BETL cells are diminished and BETL marker gene expression is compromised in mutant kernels.Transposon tagging identified the emp6 locus as encoding a putative plant organelle RNA recognition（PORR） protein,1 of 15 PORR family members in maize.The emp6 transcript is widely detected in plant tissues with highest Researclevels in embryos and developing kernels.EMP6-green fluorescent protein（GFP） fusion proteins transiently expressed in Nicotiana benthamiana leaves were targeted specifically to mitochondria.These results suggest that BETL cell differentiation might be particularly energy intensive,or alternatively,that mitochondria might confer a developmental function.

Mechanosensation of osteocyte with collagen hillocks and primary cilia under pressure and electric field stimulation

Mechanosensors are the most important organelles for osteocytes to perceive the changes of surrounding mechanical environment.To evaluate the biomechanical effectiveness of collagen hillock,cell process and primary·cilium in lacunar-canalicular system(LCS),we developed pressure-electricity-structure interaction models by using the COMSOL Multiphysics software to characterize the deformation of collagen hillocks-and primary cilium-based mechanosensors in osteocyte under fluid flow and electric field stimulation.And mechanical signals(pore pressure,fluid velocity,stress,deformation)were analyzed in LCS.The effects of changes in the elastic modulus of collagen hillocks,the number and location of cell processes,the length and location of primary cilia on the mechanosensitivity and the overall poroelastic responses of osteocytes were studied.These models predict that the presence of primary cilium and collagen hillocks resulted in significant stress amplifications(one and two orders of magnitude larger than osteocyte body)on the osteocyte.The growth of cell process along the long axis could stimulate osteocyte to a higher level than along the short axis.The Mises stress of the basal body of primary cilia near the top of osteocyte is 8 Pa greater than that near the bottom.However,the presence of collagen hillocks and primary cilium does not affect the mechanical signal of the whole osteocyte body.The established model can be used for studying the mechanism of bone mechanotransduction at the multiscale level.