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We report five types of patterns with square symmetry, including three novel types obtained by inserting a specially designed grid photonic crystal (PC) into a dielectric barrier discharge system. They are studied using an intensified charge-coupled device camera and photomultiplier tubes. The three novel types of patterns are a square pattern with one structure, a square superlattice pattern with four sublattices and a (1/4)K grid (K grid is the basic wave vector of the grid), and another square pattern with a complex inversion discharge sequence. From the application viewpoint, the five types of patterns can be used as plasma photonic crystals (PPCs). Their band diagrams under a transverse-magnetic wave simulated by the finite element method show that there are a large number of band gaps. Compared with the original PC with only a unidirectional band gap, the five types of PPCs have tunable and omnidirectional band gaps, which is very important in controlling the propagation of electromagnetic waves in the mm-wave region. The experimental results enrich the pattern types in the dielectric barrier discharge system and provide a method for obtaining PPCs with symmetry controllability and bandgap tunability.

The enhancement of plasma generation in atmospheric pressure dielectric barrier discharge (DBD) is gaining increasing interest for various plasma applications. In this paper, the effect of surface charges moving with the rotating dielectric plate on improving the generation of streamer channels is investigated by a statistical analysis of electrical measurements, optical diagnostics, and numerical simulation in a needle-plate DBD device with a rotating dielectric plate. Results suggest that rotating the dielectric plate can improve the spatiotemporal distribution of streamer channels by inducing a bending of the streamer channels and an increase in the number of discharges. Statistical results show that the number of current pulse and discharge energy are increased by 20% and 47%, respectively, at the rotating speed of 160 rps (revolution per second). Based on the interaction between the applied electric field and the electric field induced by surface charges, a formula is proposed to govern the effect of rotating the dielectric plate on the discharge energy and streamer bending. To further understand the mechanism of the influence of rotating the dielectric plate on plasma properties, a 2D fluid model is implemented, and the reduced electric field and streamer propagation are analyzed. Results show that the effective transfer and reuse of surface charges play an important role in the enhancement of plasma generation.

Regenerative medicine (RM) has the potential to restore or establish normal function of cells, tissues and organs that have been lost due to age, disease or injury. It is common for the site of raw material collection, site of manufacture and site of clinical use to be different for RM products, and at the same time cells must remain viable and functional during transportation among different sites. Freezing products down to cryogenic temperatures along with cold chain transportation has become an effective method of preserving RM products. The quality of RM products along this supply chain represents the cumulative effects of all of the processing steps and all of the reagents used in the process. A variety of sources of variability in the preservation of RM products can result in both cell losses and greater variability in the quality of RM products. The purpose of this article is to review the sources of variability in the preservation process as well as the methods by which variability can be controlled or avoided.

Raman spectroscopy has been gaining in popularity for noninvasive analysis of single cells. Raman spectra and images deliver meaningful information regarding the biochemical, biophysical, and structural properties of cells in various states. Low-temperature Raman spectroscopy has been applied to verify the presence of ice inside a frozen cell and to illustrate the distribution of both penetrating and non-penetrating cryoprotectants. This chapter delineates Raman cryomicroscopic imaging of single cells as well as sample handling for spectroscopic measurements at subzero temperature. The experimental setup is depicted with a special emphasis on a custom-built temperature-controlled cooling stage. The use of Raman cryomicroscopic imaging is demonstrated using Jurkat cells cryopreserved in a sucrose solution. Moreover, strategies for determining intracellular ice formation (IIF) and analysis of sucrose partitioning across the cell membrane are presented.

A series of Zr incorporated small crystal size Y zeolites were successfully synthesized by a direct hydrothermal method, and the corresponding NiW catalysts were prepared for the hydrocracking of vacuum gas oil (VGO). The synthesized zeolites and prepared catalysts were characterized by XRD, SEM, FTIR, Pyridine FTIR, H2-TPR and TEM techniques. The results show that the synthesized zeolites have uniform morphology and small crystal size, while Zr4+ incorporated into the framework of Y zeolite has been confirmed by XRD and FTIR. The amount of acid sites of xZrY zeolite slightly increases compared with that of Y zeolite by Pyridine FTIR. Moreover, the Zr4+ incorporation into Y zeolite can increase the W species reducibility, modulate the length and stacking of WS2 phase, and enhance the W species dispersion on the catalyst surface by H2-TPR and TEM, which favor to improve the hydrogenation activity of the catalyst to tune the balance between cracking activity and hydrogenation/dehydrogenation activity. Hence, the catalyst containing xZrY zeolite exhibits not only higher yield and selectivity of middle distillate but also slightly higher conversion of VGO compared with the catalyst containing Y zeolite.

This study examined the post-thaw recovery of Jurkat cells cryopreserved in three combinations of five osmolytes including trehalose, sucrose, glycerol, mannitol, and creatine. Cellular response was characterized using low-temperature Raman spectroscopy, and variation of post-thaw recovery was analyzed using statistical modeling. Combinations of osmolytes displayed distinct trends of post-thaw recovery, and a nonlinear relationship between compositions and post-thaw recovery was observed, suggesting interactions not only between different solutes but also between solutes and cells. The post-thaw recovery for optimized cryoprotectants in different combinations of osmolytes at a cooling rate of 1°C/min was comparable to that measured with 10% dimethyl sulfoxide. Statistical modeling was used to understand the importance of individual osmolytes as well as interactions between osmolytes on post-thaw recovery. Both higher concentrations of glycerol and certain interactions between sugars and glycerol were found to typically increase the post-thaw recovery. Raman images showed the influence of osmolytes and combinations of osmolytes on ice crystal shape, which reflected the interactions between osmolytes and water. Differences in the composition also influenced the presence or absence of intracellular ice formation, which could also be detected by Raman. These studies help us understand the modes of action for cryoprotective agents in these osmolyte solutions.

Hematopoietic stem cell (HSC) therapy is widely used to treat a growing number of hematological and non-hematological diseases. Cryopreservation of HSCs allows for cells to be transported from the site of processing to the site of clinical use, creates a larger window of time in which cells can be administered to patients, and allows sufficient time for quality control and regulatory testing. Currently, HSCs and other cell therapies conform to the same cryopreservation techniques as cells used for research purposes: cells are cryopreserved in dimethyl sulfoxide (DMSO) at a slow cooling rate. As a result, HSC therapy can result in numerous adverse symptoms in patients due to the infusion of DMSO. Efforts are being made to improve the cryopreservation of HSCs for clinical use. This review discusses advances in the cryopreservation of HSCs from 2007 to the present. The preclinical development of new cryoprotectants and new technology to eliminate cryoprotectants after thawing are discussed in detail. Additional cryopreservation considerations are included, such as cooling rate, storage temperature, and cell concentration. Preclinical cell assessment and quality control are discussed, as well as clinical studies from the past decade that focus on new cryopreservation protocols to improve patient outcomes.

There is considerable interest in the use of sugars to preserve cells. In this study, low temperature Raman spectroscopy was used to characterize the behaviors of sucrose during freezing. The hydrogen bond network between sucrose and water was investigated at -10 °C and -50 °C, and the Raman spectra showed strengthened sucrose-water and sucrose-sucrose hydrogen bonds in more concentrated sucrose solution at -50 °C. The concentration of sucrose at the ice interface increased as the ice density decreased, and it plateaued across a narrow channel of nonfrozen sucrose solution before it decreased toward the next ice interface. The biophysical environment at interfaces between the cell and nonfrozen sucrose solution and between the cell and extracellular ice was also studied. A thin layer of nonfrozen sucrose solution was observed at the interface between the cell and extracellular ice. The extracellular concentration of sucrose at this interface was generally lower than that of bulk nonfrozen sucrose solution. The variation of sucrose concentration outside different regions of the cell membrane suggests that the chemical environment around the cell during freezing may be more heterogeneous than previously thought. Raman spectra and images also showed colocalization of nonfrozen sucrose solution and the cell, which implied that direct interaction between sucrose and cell membrane might be responsible for protective properties of sucrose. Sucrose was predominantly distributed outside the cell, and the observation of strong partitioning of sucrose across the cell membrane is consistent with substantial cell dehydration detected by the Raman spectra. This work enhances our understanding of the behaviors of sucrose solution and its interactions with cells at low temperature and can improve cryopreservation protocols of cells frozen in a sucrose-based media.

Inadequate preservation methods of human induced pluripotent stem cells (hiPSCs) have impeded efficient reestablishment of cell culture after the freeze–thaw process. In this study, we examined roles of the cooling rate, seeding temperature, and difference between cell aggregates (3–50 cells) and single cells in controlled rate freezing of hiPSCs. Intracellular ice formation (IIF), post-thaw membrane integrity, cell attachment, apoptosis, and cytoskeleton organization were evaluated to understand the different freezing responses between hiPSC single cells and aggregates, among cooling rates of 1, 3, and 10°C/min, and between seeding temperatures of −4°C and −8°C. Raman spectroscopy images of ice showed that a lower seeding temperature (−8°C) did not affect IIF in single cells, but significantly increased IIF in aggregates, suggesting higher sensitivity of aggregates to supercooling. In the absence of IIF, Raman images showed greater variation of dimethyl sulfoxide concentration across aggregates than single cells, suggesting cryoprotectant transport limitations in aggregates. The ability of cryopreserved aggregates to attach to culture substrates did not correlate with membrane integrity for the wide range of freezing parameters, indicating inadequacy of using only membrane integrity-based optimization metrics. Lower cooling rates (1 and 3°C/min) combined with higher seeding temperature (−4°C) were better at preventing IIF and preserving cell function than a higher cooling rate (10°C/min) or lower seeding temperature (−8°C), proving the seeding temperature range of −7°C to −12°C from literature to be suboptimal. Unique f-actin cytoskeletal organization into a honeycomb-like pattern was observed in postpassage and post-thaw colonies and correlated with successful reestablishment of cell culture.

In the unique supply chain of cellular therapies, preservation is important to keep the cell product viable. Many factors in cryopreservation affect the outcome of a cell therapy: (i) formulation and introduction of a freezing medium, (ii) cooling rate, (iii) storage conditions, (iv) thawing conditions and (v) post-thaw processing. This article surveys clinical trials of cellular immunotherapy that used cryopreserved regulatory, chimeric antigen receptor or gamma delta T cells, dendritic cells or natural killer (NK) cells. Several observations are summarized from the given information. The aforementioned cell types have been similarly frozen in media containing 5-10% dimethyl sulfoxide (DMSO) with plasma, serum or human serum albumin. Two common freezing methods are an insulated freezing container such as Nalgene Mr. Frosty and a controlled-rate freezer at a cooling rate of -1°C/min. Water baths at approximately 37°C have been commonly used for thawing. Post-thaw processing of cryopreserved cells varied greatly: some studies infused the cells immediately upon thawing; some diluted the cells in a carrier solution of varying formulation before infusion; some washed cells to remove cryoprotective agents; and others re-cultured cells to recover cell viability or functionality lost due to cryopreservation. Emerging approaches to preserving cellular immunotherapies are also described. DMSO-free formulations of the freezing media have demonstrated improved preservation of cell viability in T lymphocytes and of cytotoxic function in natural killer cells. Saccharides are a common type of molecule used as an alternative cryoprotective agent to DMSO. Improving methods of preservation will be critical to growth in the clinical use of cellular immunotherapies.

We report a continuous three-dimensional pattern with the symmetry of D2h in dielectric barrier discharge by introducing surface discharges (SDs) with a specially designed device for the first time. From the front view, it consists of dark spots and bright bars, which correspond to the conventional volume discharge (VD) and novel VD. Different from the conventional VD, the novel VD bends through three gas gaps and discharges multiple times per half-voltage-cycle, which results from the complex interaction between the VD and SD. By using this device, three surfaces of the sample inserted between electrodes are processed simultaneously, which greatly improves the plasma processing efficiency.

This study examined the post-thaw recovery of Jurkat cells cryopreserved in single osmolyte solutions containing sucrose, glycerol or isoleucine, as well as in a combination of the three osmolytes. Cell response was determined using low temperature Raman Spectroscopy and variation in post-thaw recovery with composition was analyzed using statistical modeling. Post-thaw recovery of Jurkat cells in single osmolyte was low. A combination of the osmolytes displayed a non-linear relationship between composition and post-thaw recovery, suggesting that interactions exist between the different solutes. The post-thaw recovery for an optimized multicomponent solution was comparable to that observed using 10% dimethyl sulfoxide and a cooling rate of 1 °C/min. Statistical modeling was used to characterize the importance of each osmolyte in the combination and test for interactions between osmolytes. Higher concentrations of glycerol increase post-thaw recovery and interactions between sucrose and glycerol, as well as sucrose and isoleucine improve post-thaw recovery. Raman images clearly demonstrated that damaging intracellular ice formation was observed more often in the presence of single osmolytes as well as non-optimized multi-component solution compositions.

Raman microspectroscopy was used to quantify freezing response of cells to various cooling rates and solution compositions. The distribution pattern of cytochrome c in individual cells was used as a measure of cell viability in the frozen state and this metric agreed well with the population-averaged viability and trypan blue staining experiments. Raman imaging of cells demonstrated that intracellular ice formation (IIF) was common and did not necessarily result in cell death. The amount of intracellular ice as well as ice crystal size played a role in determining whether or not ice inside the cell was a lethal event. Intracellular ice crystals were colocated to the sections of cell membrane in close proximity to extracellular ice. Increasing the distance between extracellular ice and cell membrane decreased the incidence of IIF. Reducing the effective stiffness of the cell membrane by disrupting the actin cytoskeleton using cytochalasin D increased the amount of IIF. Strong intracellular osmotic gradients were observed when IIF was present. These observations support the hypothesis that interactions between the cell membrane and extracellular ice result in IIF. Raman spectromicroscopy provides a powerful tool for observing IIF and understanding its role in cell death during freezing, and enables the development, to our knowledge, of new and improved cell preservation protocols.

Three catalysts NiW/Al 2 O 3 , NiW–P/Al 2 O 3 and NiW–CA/Al 2 O 3 with different morphologies but similar pore structures and acidity properties were prepared for studying the effect of morphology properties on the hydrodesulfurization (HDS) activity for individual sulfur compounds in fluid catalytic cracking (FCC) diesel. The morphology properties of the selected catalysts in oxidation and sulfidation states were characterized and the contents of individual sulfur compounds were determined by gas chromatography–pulse flame photometric detector (GC–PFPD). The results showed that NiW–P/Al 2 O 3 possessed the highest edge density of WS 2 phase and NiW–CA/Al 2 O 3 had the highest stacking degree of multilayered WS 2 phase. The HDS assessment showed that NiW–CA/Al 2 O 3 demonstrated positive effects on the HDS of refractory sulfur compounds like 4,6-dimethyldibenzothiophene (4,6-DMDBT) or dibenzothiophene (DBT) with alkyl substitutes containing 3 carbons (C 3 DBT) but slight negative effects on the HDS of simple sulfur compounds such as benzothiophene (BT) with alkyl substitutes containing 1 ~ 5 carbons (C 1 ~ C 5 BT) and DBT with alkyl substitutes containing 1 carbon (C 1 DBT); while NiW–P/Al 2 O 3 favored for the HDS of simple sulfur compounds. The present results indicated that the morphology of WS 2 phase has a great influence on the HDS selectivity for different structured sulfur compounds.

USY zeolites were modified by zirconium, phosphorus and both zirconium and phosphorus, and the corresponding catalysts were prepared for hydrocracking of vacuum gas oil. The results showed that Zr-modified USY enhanced W species dispersion on catalyst surface, weakened interaction of W species with support and improved W species reducibility, leading to formation of highly stacked WS2 slabs and higher sulfidation degree of W species, which was favorable for the enhancement of hydrogenation activity. The influence of the modification with zirconium and phosphorus on these properties of catalyst was more pronounced than that of zirconium or phosphorus modification because of the synergistic action of phosphorus and zirconium. The catalyst containing Zr-USY had slightly lower hydrocracking activity than that containing USY owing to a diminution of acid sites, but presented obviously greater middle distillate selectivity arising from the improvement of hydrogenation activity. The middle distillate selectivity on catalyst containing Zr-P-USY was higher than that on catalysts containing Zr-USY or P-USY, corresponding to its more effective catalyst properties.

There is demand for non-dimethyl sulfoxide (DMSO) cryoprotective agents that maintain cell viability without causing poor postthaw function or systemic toxicity. The focus of this investigation involves expanding our understanding of multicomponent osmolyte solutions and their ability to preserve cell viability during freezing. Controlled cooling rate freezing, Raman microscopy, and differential scanning calorimetry (DSC) were utilized to evaluate the differences in recovery and ice crystal formation behavior for solutions containing multiple cryoprotectants, including sugars, sugar alcohols, and small molecule additives. Postthaw recovery of mesenchymal stem cells (MSCs) in solutions containing multiple osmolytes have been shown to be comparable or better than that of MSCs frozen in 10% DMSO at 1°C/min when the solution composition is optimized. Maximum postthaw recovery was observed in these multiple osmolyte solutions with incubation times of up to 2 h before freezing. Raman images demonstrate large ice crystal formation in cryopreserved cells incubated for shorter periods of time (∼30 min), suggesting that longer permeation times are needed for these solutions. Recovery was dependent upon the concentration of each component in solution, and was not strongly correlated with osmolarity. It is noteworthy that the postthaw recovery varied significantly with the composition of solutions containing the same three components and this variation exhibited an inverted U-shape behavior, indicating that there may be a “sweet spot” for different combinations of osmolytes. Raman images of freezing behavior in different solution compositions were consistent with the observed postthaw recovery. Phase change behavior (solidification patterns and glass-forming tendency) did not differ for solutions with similar osmolarity, but differences in postthaw recovery suggest that biological, not physical, methods of protection are at play. Lastly, molecular substitution of glucose (a monosaccharide) for sucrose (a disaccharide) resulted in a significant drop in recovery. Taken together, the information from these studies increases our understanding of non-DMSO multicomponent cryoprotective solutions and the manner by which they enhance postthaw recovery.

The effects of the Y zeolite crystallite size on the hydrocracking activity and middle distillate selectivity in hydrocracking of vacuum gas oil have been investigated using Ni–W catalysts with zeo...

This article presents a novel method for preparing hydrodenitrogenation (HDN) catalysts via combined phosphorous modification of alumina and ethylenediaminetetraacetic acid (EDTA)-assisted dispersion of active metals. The results showed that the catalyst prepared with this method possessed high dispersion of nickel and tungsten species, ascribed to EDTA addition. Simultaneously, high sulfidation degree of tungsten and nickel species was obtained due to the addition of phosphorous and EDTA. So the catalyst prepared by this method exhibited a greatly enhanced hydrodenitrogenation activity than the conventional method prepared.

We report on the interaction between surface discharges (SDs) and volume discharges (VDs) in the spot-line white-eye hexagonal superlattice pattern in dielectric barrier discharge using an intensified charge-coupled device camera, a high-speed video camera, and a spectrograph. The small spot-lines and halos discharge in the first pulse and the second pulse at the rising edge of the voltage, respectively. The central spots discharge at the falling edge of voltage. The small spots are VDs whose discharge time is incompletely simultaneous. The lines are direction-selective SDs induced by small spots. It is found that the above phenomena result from the interaction between SDs and VDs. The incompletely simultaneous discharge of the small spots is due to the different quantities of wall charges transported by the SDs induced by small spots. The directional selectivity of the SDs results from that the SDs are extinguished when they are close to halos due to the neutralization of the wall charge of halos (VDs) and the wall charge of SDs, while they can stretch to other small spots.

When the signal in a transform domain is sparse or compressible, it could be projected to low-dimensional vector utilizing measurement matrix. This projection maintains the information required by reconstructing signal. By research about the basic theories for compressed sensing, this article adopted FFT and DWT as the transform matrix Φ respectively, the random matrix as the sampling φ, then analyzed the coherence among them in addition to the sparsity of the sampling signals, explored further the ability of the two methods for recovering signals.

Forecast error is the main and direct reason for the increase of product inventory in the garment enterprise whose product is based on market forecast. Product customer satisfaction can reflect market prospect of the product effectively. The appraisal and analysis of the product customer satisfaction can improve the accuracy of garment enterprises market forecast, and increase the possibility of success in the product research and development. The measurement model of product customer satisfaction is the foundation of product customer satisfaction analysis system development. The measurement method of the product customer satisfaction is based on the main factors which affect the garment product customer satisfaction, and analysis on the factors from different levels and aspects. And the corresponding measurement model is also established. The evaluation and analysis on the measurement result of the product customer satisfaction and influencing factors would benefit the enterprise to adjust product development plan in time and product garment products which satisfy the market demand better according to the relationship and current situation among different affective factors and product satisfaction, thus further improve the product customer satisfaction for garment enterprises.