The protective effect of oleic acid on Lactiplantibacillus plantarum during freeze-drying

Membrane characteristics are determined by the fatty acids composition,which affects survival rates after freeze-drying.However,it is unknown which composition provides the greatest effect.In this study,we found that the addition of Tween 80 and Tween 20 significantly increased survival rates of Lactiplantibacillus plantarum,which reached a maximum of 93.1%.Conversely,Tween 60 caused a significant decrease.We further found that the difference between the effects of adding Tween 80 and Tween 60 was the change in oleic acid contents.To verify the role of oleic acid,we used CRISPR-Cas9 to knock-out the key synthesis gene cla-er.The survival rates of L.plantarum AR113Δcla-er declined to 5.48%.The addition of oleic acid restored the rates to those of wild type strains.Moreover,the membrane integrity and fl uidity of knockout strains markedly decreased.This is the fi rst confi rmation that Tween 80 or Tween 20 increases the survival rate by increasing the content of oleic acid in the cell membrane.These fi ndings also indicated that oleic acid in cell membranes has a substantial protective effect on L.plantarum during freeze-drying.

Facile synthesis of Li3V2（PO4）3/C cathode material for lithium-ion battery via freeze-drying

In this work, we report a facile route for the synthesis of Li3V2(PO4)3/C cathode material via freezedrying and then calcination. The effect of calcination temperature on the electrochemical properties of the Li3V2(PO4)3/C is also investigated. When used as a lithium-ion battery cathode, the optimized Li3V2(PO4)3/C (LVP-800) through calcination at 800 ℃ exhibits a high initial charge and discharge capacity. The excellent electrochemical performance of LVP-800 is attributed to the good crystallinity and uniform morphology of the electrode material. In addition, the residual carbon can also improve the conductivity and buffer the volume expansion during the Li-ion extraction/reinsertion. Meanwhile, charge compensation also plays an important role in excellent electrochemical performance.

Microstructure of porous Cu fabricated by freeze-drying process of CuO/camphene slurry

Porous Cu with macroscopically aligned channels was synthesized using a freeze-drying process.Camphene-based CuO slurry was prepared by milling at 60 °C with a small amount of dispersant.Freezing of a slurry was done at 25 °C while unidirectionally controlling the growth direction of the camphene.Pores were generated subsequently by sublimation of the camphene during drying.The green body was hydrogen-reduced at 300 °C for 30 min,and sintered in the furnace at 700 °C for 1 h under a hydrogen atmosphere.Microstructural observation reveals that all of the sintered samples are composed of only Cu phase and show macroscopic open pores with an average size of 100 μm which are aligned along its macroscopic growth direction.The internal wall of the macroscopic aligned pore shows relatively small pores due to the traces of the camphene left between the concentrated Cu particles on the internal wall.Increase in the porosity and pore size with increasing camphene content was explained by the change of the growth behavior of the camphene crystals.

Luminescence properties of nitrogen-rich Ca-SiAlON:Eu2+ phosphors prepared by freeze-drying assisted combustion synthesis

Nitrogen-rich Eu2+-doped Ca-α-SiAlON phosphors(Cam/2-xSi12-m-nAlm+nOnN16-n:xEu) were synthesized by a freeze-drying assisted combustion synthesis(CS) route. Fast-synthesized products with high purity and uniform particle morphology were confirmed by X-ray diffraction(XRD) and scanning electron microscopy(SEM). The analysis of lattice parameters by comparison with empirical equations showed that the as-prepared phosphors had low oxygen content. A series of samples were prepared according to the stoichiometry of Cam/2-0.08Si12-mAlmN16:0.08 Eu for further research. The influences of m value on the luminescence properties were investigated in detail. As m increased, a redshift phenomenon was observed in both the excitation and emission spectra. First-principle electronic structure calculations showed that the 3d energy level of Ca played an important role in the occurrence of the redshift phenomenon.

Application of near infrared spectroscopy in monitoring the moisture content in freeze-drying process of human coagulation factor VIII

As an important process analysis tool,near infrared spectroscopy(NIRS)has been widely used in process monitoring.In the present work,the feasibility of NIRS for monitoring the moisture content of human coagulation factor VIII(FVIII)in freeze-drying process was investigated.A partial least squares regression(PLS-R)model for moisture content determination was built with 88 samples.Different pre-processing methods were explored,and the best method found was standard normal variate(SNV)transformation combined with 1st derivation with Savitzky–Golay(SG)15 point smoothing.Then,four different variable selection methods,including uninformative variable elimination(UVE),interval partial least squares regression(iPLS),competitive adaptive reweighted sampling(CARS)and manual method,were compared for eliminating irrelevant variables,and iPLS was chosen as the best variable selection method.The correlation coe±cient(R),correlation coe±cient of calibration set(Rcal),correlation coefficient of validation set(Rval),root mean square errors of cross-validation(RMSECV)and root mean square errors of prediction(RMSEP)of PLS model were 0.9284,0.9463,0.8890,0.4986% and 0.4514%,respectively.The results showed that the model for moisture content determination has a wide range,good linearity,accuracy and precision.The developed approach was demonstrated to be a potential for monitoring the moisture content of FVIII in freeze-drying process.

Chicken Embryo Inhibition Test of Recombinant Freeze-drying Chicken Interferon against Newcastle Disease Virus( NDV) F_(48)E_(10)

The paper was to study the inhibitory effect of recombinant freeze-drying chicken interferon against Newcastle disease virus （NDV） F48E10. Nine-day-old chicken embryos were inoculated with recombinant freeze-drying chicken interferon via allaotoic sack, while 10-day-old chicken embryos were inoculated with NDV F48E10, and in vivo protective efficacy of interferon on chichen embryos was studied. The results showed that the recombinant freeze-drying chicken interferon at the dose of 1.28 mg/embryo reached the protection ratio of 90% on chicken embryo infected by F48E10.

Growth and Freeze-Drying Optimization of Bifidobacterium crudilactis

Bifidobacterium crudilactis FR62/b/3 belongs to a new population of bifidobacteria isolated from raw milk and raw milk cheese. The objective of this work was to study the large scale culture of the strain and its stability in a dry formulation. Growth rate of Bifidobacterium crudilactis FR62/b/3 was optimal at a pH of 5.0 and a temperature of 37°C. At a temperature growth of 33°C and a pH of 5.0, the stationary phase was reached after 22 h, the viable cell number and the mean dry biomass concentration were respectively of 8.3 × 109 CFU/mL and of 2.1 g/L. Resistance of Bifidobacterium crudilactis FR62/b/3 to freeze-drying and effect of a variety of cryoprotectants to maintain the viability were also evaluated. Sorbitol was the most suitable cryoprotectant for freeze-drying as well as storage whereas sucrose and monosodium glutamate were only efficient during storage.

Freeze-drying synthesis of O,N-CeF_(3) with enhanced photocatalytic oxygen evolution

Drying methods have been verified to have a considerable impact on photocatalytic efficiency via altering surface area.In this study,the preparations of O,N-CeF_(3) under identical conditions using the vacuum freezing method and the oven method are compared.Surface hydroxyl,as opposed to adsorbed oxygen in CeF_(3)-O,is the main component of O faults on the surface of CeF_(3)-V.Small particle size and the doping atom defects of CeF_(3)-V allow for more efficient separation and faster migration of photogenerated charge carriers.CeF_(3)-V has an oxygen evolution rate of up to 1.4138 mmol/(g·h)and an apparent quantum yield of 90.90%at 550 nm.Energy tails are produced as a result of the doping O and N changing the intrinsic band structures.CeF_(3)-V shows a secondary conduction band potential that is sufficient for satisfying the minimal water oxidation potential simultaneously.These elucidate that defects in the states of doping O and N significantly influence CeF_(3) energy levels.Focusing on how the drying process affects the band structure and encourages carriers'separation via defects is valuable,which affects how well the photocatalysis works.

Synthesis of W-Y2O3 alloys by freeze-drying and subsequent low temperature sintering:Microstructure refinement and second phase particles regulation

In this work,W-Y2 O3 alloys are prepared by freeze-drying and subsequent low temperature sintering.The average size of reduced W-Y2 O3 composite powders prepared by freeze-drying method is only 18.1 nm.After low temperature sintering of these composite nanopowders,the formed W-Y2 O3 alloys possess a smaller grain size of 510 nm while maintaining a comparatively higher density of 97.8%.Besides a few submicron Y2 O3 particles(about 100-300 nm)with a W-Y-O phase diffusion layer on their surface distribute at W grain boundaries,lots of nano Y2 WO6 particles(<20 nm)exist in W matrix.Moreover,many Y6 WO12(<10 nm)particles exist within submicron Y2 O3 particles.The formation of these ternary phases indicates that some oxygen impurities in the W matrix can be adsorbed by ternary phases,resulting in the purification of W matrix and the strengthening of phase boundaries.The combined action of the above factors makes the hardness of the sintered W-Y2 O3 alloys in our work as high as 656.6±39.0 HV0.2.Our work indicates that freeze-drying and subsequent low temperature sintering is a promising method for preparing high performance W-Y2 O3 alloys.

Additive-free porous assemblies of Ti3C2Tx by freeze-drying for high performance supercapacitors

Ti3C2Tx has shown great potential in energy storage filed,but the restacking between Ti3C2Tx nanosheets seriously hampers the maximization of its capacitance.In this study,we rationally designed and synthesized porous Ti3C2Tx assemblies without any additive by introducing ice as spacers using a facile freeze-drying method.The porous Ti3C2Tx assemblies have a three-dimensional network structure,which consists of ultra large Ti3C2Tx lamellar walls and lots of macro-and mesopores.It has been proven that there are more-O groups on the surface of the porous Ti3C2Tx assemblies than the Ti3C2Tx film.The porous Ti3C2Tx assemblies deliver a maximum areal capacitance of 1668 mF/cm^2 when the mass loading is 8.4 mg/cm^2,an optimized specific capacitance of 247.2 F/g when the mass loading is 5.3 mg/cm^2,and87%capacitance retention over 10000 cycles.The symmetric solid-state supercapacitors based on the porous Ti3C2Tx assemblies show an areal capacitance of 355.8 mF/cm^2,the maximum power density of50 mW/cm^2 and an outstanding flexibility under different deformation.

Refined microstructure and enhanced mechanical properties in Mo-Y_(2)O_(3)alloys prepared by freeze-drying method and subsequent low temperature sintering

The ultrafine Mo-Y_(2)O_(3)composite powders were successfully synthesized by innovative freeze-drying method.Consequently,the freeze-dried Mo-Y_(2)O_(3)composite powders with high sintering activities possess an average grain size of 54 nm.After low temperature sintering at 1600°C,the Mo-Y_(2)O_(3)alloys maintaining a high density(99.6%)have the finest grain size(620 nm)comparing with available literature about oxide dispersion strengthened molybdenum alloy(ODS-Mo).The oxide particles remain their small size(mainly<50 nm)within Mo grains and at Mo grain boundaries.Furthermore,the Y_(5)MO_(2)O_(12)particles were firstly observed within Mo matrix,and its formation can absorb nearby oxygen impurities,which involves the purification of Mo matrix.The mechanical properties show that Mo-Y_(2)O_(3)alloy possess a high hardness of 487±28 HV_(0.2),a high yield strength of 902 MPa,a high compressive strength of1110 MPa,respectively.Our work suggests that freeze-drying and subsequent low temperature sintering can shed light on the preparation of ultrafine ODS-Mo alloys with high performance.

Freeze-drying-assisted Synthesis of Mesoporous CoMoO4 Nanosheets as Anode Electrode Material for Enhanced Lithium Batteries

A facile and green freeze-drying-assisted method was proposed to synthesize C0MoO4 mesoporous nano-sheets(MPNSs).The resulting product exhibits a Mgh specific capacity and good rate perfomance when evalimte an anode material for lithium-ion batteries(LIBs).The reversible specific capacity can be kept at 1105.2 mA·h·g^-1 after 100 cycles at a current density of 0.2 A/g.Even at the current densities of 1 and 4 A/gs the CoMoO4 MPNSs electrode can still retain the reversible capacities of 1148.7 and 540 mA·h·g^-1,respectively.Furthermore,the full cell(LiPePO4 catliode/CoMoO4 MPNSs anode)displays a stable discharge capacity of 146.7 mA·h·g^-1 at 0.1 C(1 C=170 mA/g)together with an initial coulombic efficiency of 98.2%.In addition,the CoMoO4 crystal structure is destroyed and reduced into Co^0 and Mo^0 in the first discharge process.In the subsequent cycles,the attractive Li storage properties come from the reversible conversions between Co/Co^2+and Mo/Mo^6+.The improved electroche-mical performance of CoMoO4 MPNSs is mainly attributed to their unique porous structures,which not only possess a good ion diffusion and electronic conduction pathway,but also provide many cavities to alleviate the volume changes during repeated cycling.This work offers a new perspective to the design of other porous electrode materials with a good energy storage performance.

Freeze-Drying Formulations Increased the Adenovirus and Poxvirus Vaccine Storage Times and Antigen Stabilities

Successful vaccines induce specific immune responses and protect against various viral and bacterial infections. Noninactivated vaccines, especially viral vector vaccines such as adenovirus and poxvirus vaccines, dominate the vaccine market because their viral particles are able to replicate and proliferate in vivo and produce lasting immunity in a manner similar to natural infection. One challenge of human and livestock vaccination is vaccine stability related to the antigenicity and infectivity. Freeze-drying is the typical method to maintain virus vaccine stability, while cold chain transportation is required for temperatures about 2 °C–8 °C. The financial and technological resource requirements hinder vaccine distribution in underdeveloped areas. In this study, we developed a freeze-drying formula consisting of bovine serum albumin(BSA), L-glutamic acid(L-Glu), polyethylene glycol(PEG), and dextran(DEX) to improve the thermal stability and activity of viral vaccines, including vaccinia recombinant vaccine(rTTV-OVA) and adenovirus vaccine(Ad5-ENV). We compared a panel of five different formulations(PEG: DEX: BSA: L-GLU = 50:9:0:0(#1), 50:5:4:0(#2), 50:10:9:0(#3),50:0:0:9(#4), and 50:1:0:8(#5), respectively) and optimized the freeze-drying formula for rTTV-OVA and Ad5-ENV. We found that the freeze-drying formulations #2 and #3 could maintain rTTV-OVA infectivity at temperatures of 4 °C and25 °C and that r TTV-OVA immunogenicity was retained during lyophilization. However, formulations #4 and #5 maintained Ad5-ENV infectivity under the same conditions, and Ad5-ENV immunogenicity had maximum retention with freeze-drying formulation #4. In summary, we developed new freeze-drying formulations that increased virus vaccine storage times and retained immunogenicity at an ambient temperature.

PREPARATION OF POROUS NANOCOMPOSITE SCAFFOLDS WITH HONEYCOMB MONOLITH STRUCTURE BY ONE PHASE SOLUTION FREEZE-DRYING METHOD

Biodegradable porous nanocomposite scaffolds of poly（lactide-co-glycolide）（PLGA） and L-lactic acid（LAc） oligomer surface-grafted hydroxyapatite nanoparticles（op-HA） with a honeycomb monolith structure were fabricated with the single-phase solution freeze-drying method.The effects of different freezing temperatures on the properties of the scaffolds,such as microstructures,compressive strength,cell penetration and cell proliferation were studied.The highly porous and well interconnected scaffolds with a tunable pore structure were obtained.The effect of different freezing temperature（4℃,-20℃,-80℃and -196℃） was investigated in relation to the scaffold morphology,the porosity varied from 91.2%to 83.0%and the average pore diameter varied from（167.2±62.6）μm to（11.9±4.2）μm while theσ_（10） increased significantly.The cell proliferation were decreased and associated with the above-mentioned properties.Uniform distribution of op-HA particles and homogeneous roughness of pore wall surfaces were found in the 4℃frozen scaffold.The 4℃frozen scaffold exhibited better cell penetration and increased cell proliferation because of its larger pore size,higher porosity and interconnection.The microstructures described here provide a new approach for the design and fabrication of op-HA/PLGA based scaffold materials with potentially broad applicability for replacement of bone defects.

Freeze-drying and hot-pressing strategy to embed two-dimensional Ti_(0.87)O_(2) monolayers in commercial polypropylene films with enhanced dielectric properties

The dielectric capacitor has been widely used in advanced electronic and electrical power systems due to its capability of ultrafast charging–discharging and ultrahigh power density.Nevertheless,its energy density is still limited by the low dielectric constant(≈2.2)of the commercial dielectric polypropylene(PP).The conventional enhancement strategy by embedding inorganic fillers in PP matrix is still difficult and challenging due to that PP hardly dissolves in any inorganic/organic solvent.In this work,we develop a new strategy including freeze-drying,surface functionalization,and hot-pressing to incorporate Ti_(0.87)O_(2) monolayers in PP film.A series of uniform composited Ti_(0.87)O_(2)@PP film has been successfully fabricated with Ti0.87O2 content range of 0–15 wt%.The maximum dielectric constant of the as-prepared Ti_(0.87)O_(2)@PP film is 3.27 when the Ti_(0.87)O_(2) content is 9 wt%,which is about 1.5 times higher than that of pure PP.Our study provides a feasible strategy to embed two-dimensional material into commercial PP thin-film with superior dielectric performance for practical application.

Effects of Rosmarinic Acid on DNA Integrity and H19 Differentially Methylated Region Methylation Levels in Human Sperm Preserved by Freeze-Drying

Original Article Effects of Rosmarinic Acid on DNA Integrity and H19 Differentially Methylated Region Methylation Levels in Human Sperm Preserved by Freeze-Drying Wang Yi-Yu,Zhu Wei-Jie Published 2021-03-25 Cite as Reprod Dev Med,2021,05 Reprod Dev Med,2021,05(1):9-14.DOI:10.4103/2096-2924.309790 Abstract Objective:To investigate the effects of rosmarinic acid(RA)on the DNA integrity and methylation levels of the H19 differentially methylated region(DMR)of freeze-dried human sperm after 1 week and 6 months of storage at 4℃.Methods:Semen samples from 15 healthy normospermic donors were used in this study.The samples were divided into five groups,including the control group with fresh sperm and four experimental groups with freeze-dried sperm(1-week storage with EGTA buffer solution,Group A;1-week storage with EGTA buffer solution containing 105μmol/L RA,Group B;6-month storage with EGTA buffer solution,Group C;and 6-month storage with EGTA buffer solution containing 105μmol/L RA,Group D).DNA integrity was evaluated using the sperm chromatin dispersion test.H19 DMR methylation levels were detected by bisulfite sequencing polymerase chain reaction.Results:After 1 week of storage,no differences in sperm DNA integrity were observed among Groups A,B,and controls(P>0.05).After 6 months of storage,the sperm DNA integrity of Group D did not change significantly compared with that of the control group(P>0.05),whereas that of Group C decreased significantly(P<0.05).There were no differences in H19 DMR methylation levels among the five groups(P>0.05).Conclusions:The DNA integrity of freeze-dried human sperm can be effectively protected by adding RA within 6 months,and the H19 DMR methylation level of human sperm can be maintained for 6 months after freeze-drying.

Changes on membrane integrity and ultrastructure of human sperm after freeze-drying

Objective To observe changes on membrane integrity and ultrastructure of human sperm after freeze-drying.Methods Semen samples from both normospermic donors（group A, n=15） and infertile men with abnormal sperm parameters（group B, n=15） were enrolled into this study. These samples were freeze-dried by using a freeze-drying method. The membrane integrity in the head and tail regions of individual spermatozoon was examined by using the combined hypo-osmotic swelling-eosin Y exclusion test. Sperm ultrastructure in groups A（n=3） and B（n=3） was observed by scanning electron microscopy（SEM）.Results After freeze-drying, all spermatozoa were types I（damaged both head and tail membranes） and III（damaged head membrane and intact tail membrane） membrane integrity in groups A and B. Type III of group B had lower value than that of group A（P〈0.01）. Under SEM, intact freeze-dried spermatozoa including abnormal morphology and normal-looking morphology were observed in both groups A and B. A few freezedried sperm heads had unsmooth or fuzzy surface. Isolated sperm heads, bent tails,broken sperm tails or fragmentary tails were more frequently seen in group B than those in group A.Conclusion Freeze-dried human spermatozoa could have intact structural components. However, freeze-drying resulted in severe damage on membrane integrity and ultrastructure of sperm. Samples from infertile men would have less resistance to freeze-drying.

Viability of Two Freeze-dried Strains of Bifidobacterium Preparations at Various Temperatures during Prolonged Storage

Viability of bifidobacteria in freeze-dried probiotic products at various temperatures during prolonged storage was assessed. Bifidobacterium longum and Bifidobacterium infantis were freeze-dried. The freeze-dried preparations were stored at -18 , 4 , and 20 ℃. Cell counts were enumerated using BS agar at 37 ℃ for 48 h under anaerobic conditions at 0, 45 and 120 days. Storage at 20 ℃ showed the greatest decline in the viability of bifidobacteria, whereas that at -18 ℃ showed the least decrease.

Ag/TiO_2/freeze-dried graphene nanocomposite as a high performance photocatalyst under visible light irradiation

Ag/TiO2/freeze-dried graphene nanocomposites have been prepared via a facile one-step solvothermal method for the photocatalytic degradation of Rh B under visible light irradiation. During the solvothermal process, reduction of graphene oxide and loading of Ag/TiO2nanoparticles on graphene sheets were achieved. Investigation of chemical state of products showed that covering of Ag/TiO2surface with higher weight ratio of graphene resulting in that Ag metals in Ag/TiO2were oxidized to Ag2 O in nanocomposite structure after solvothermal process. Degree of photocatalytic activity enhancement strongly depends on the coverage of Ag/TiO2surface by porous graphene. The sample of 1 wt% porous graphene hybridized Ag/TiO2showed the highest photocatalytic activity, which is related to high migration efficiency of photoinduced of electrons and reduction of electron–hole recombination rate due to high electrical conductivity of graphene. Expanding of absorption to visible light region was ascribed to surface plasmon resonance effect of Ag metals and presence of graphene. Investigation of photocatalytic performance of formic acid as a dye-less organic pollutant showed that dye sensitization effect of Rh B molecules during evaluation of photocatalytic performance was negligible.

Study of self-made freeze-dried bilayered fibrin-binding amniotic membrane in ocular trabeculectomy in rabbits

AIM: To investigate the antifibrotic effect of freeze-dried bilayered fibrin-binding amniotic membrane on trabeculectomy in a rabbit model. METHODS: Twenty-four Japanese white rabbits were randomized into three groups: the experimental group (ocular trabeculectomy in combination with freeze-dried bilayered fibrin-binding amniotic membrane transplantation), the control group (ocular trabeculectomy in combination with natural bilayered fibrin-binding amniotic membrane) and the blank group (single trabeculectomy). Clinical observation, hematoxylin-eosin staining, Massion staining, real-time PCR and immunohistochemistry for alpha -SMA were performed on days 7, 14, 21 and 30 following surgery. RESULTS: Statistical differences were noted in survival. analysis and intraocular pressure(IOP) among groups on days 7, 14, 21 and 30 following surgery. Histology, immunohistochemistry and real-time PCR further demonstrated that trabeculectomy in combination with freeze-dried bilayered fibrin-binding amniotic membrane resulted in good wound healing and no scar formation. CONCLUSION: Self-made freeze-dried bilayered fibrin-binding amniotic membrane may inhibit the formation of scarring in glaucoma after trabeculectomy.