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.

Optimizing the Chemical Compositions of Protective Agents for Freeze-drying Bifidobacterium longum BIOMA 5920

Freeze drying has a deleterious effect on the viability of microorganisms. In front of this difficulty, the present study adopts response surface methodology to optimize the chemical compositions of protective agents to seek for maximum viability of Bifidobacterium longum BIOMA 5920 during freeze-drying. Through the compara- tive analysis of single protectant, the complex protective agents show better effect on the Bifidobacterium viability. Human-like collagen (HLC), trehalose and glycerol are confirmed as significant factors by Box-Behnken Design. The optimized formula for these three variables is tested as follows: HLC 1.23%, trehalose 11.50% and glycerol 4.65%. Under this formula, the viability is 88.23%, 39.67% higher in comparison to the control. The viable count is 1.07×10 9 cfu·g-1 , greatly exceeding the minimum viable count requirement (10 6 cfu·g-1 ).

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.

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.

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.

Technological Study on Instant Date Powder in Natural Ziziphus jujuba through Vacuum Freeze-drying

[Objective] The aim was to get optimized conditions for date powder with good color and taste.[Method] The pectinase enzymolysis and vacuum freeze-drying technology were used in the extract process of date powder.[Result] The production boasts of superior quality were with rich fragrance and uniform particle under certain process conditions.The optimized conditions for pectinase enzymolysis were:the amount of pectinase reached to 0.1% of that of date syrup,enzymolysis temperature and time were 50 ℃ and 50 min respectively,the pH value was 4.0.The optimized conditions for vaccum freeze-drying were:10% altodextrin,three times volumn of water with the thickness of 7 mm.[Conclusion] The optimized conditions were obtained in this study to produce instant date powder from Ziziphus jujuba.

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.

Preparation of norovirus GII loop mediated isothermal amplification freeze-drying microsphere reagents and its application in an on-site integrated rapid detection platform

Norovirus is an infectious disease that can cause non-bacterial gastroenteritis,which has a low infectious dose,rapid onset,and strong transmission ability;therefore,rapid and sensitive detection is essential to reduce the transmission of gastroenteritis.In the study,a norovirus GII loop-mediated isothermal amplification assay was developed and prepared into freeze-drying microspheres,and a closed-cassette-based,integrated,reagent-ambient storage,on-site instant detection platform for norovirus GII was constructed using a commercial,fully automated nucleic acid analyzer with integrated magnetic bearing based nuclear acid extraction and nucleic acid detection,with a sensitivity of 10 copies/μL,with no cross-reactivity with other 5 viruses.For 28 simulated samples,the integrated assay platform was consistent with the experimental results of reverse transcription-quantitative polymerase chain reaction(RT-qPCR)assays after conventional laboratory nucleic acid extraction.The entire process can be finished in about 1 h,which is ideal for immediate rapid detection.

Sensory Evaluation of Freeze-Dried Facial Mask and Analysis of User Profile

To thoroughly understand market opportunity of freeze-dried facial mask and deeply get insight of consumers’usage behavior and needs,evaluate sensory feelings of 10 screened commercial freeze-dried facial mask products,group test products according to the differences of sensory attributions via Principal Component Analysis(PCA)and Agglomerative Hierarchical Clustering(AHC),pick up the representative products.Freeze-dried facial mask users evaluate satisfaction degree of picked up products and participate survey of usage behavior/cognition.Analyze consumer data by AHC to get consumer segmentations and their profile.The test results show that,sensory data and consumer data,which is from consumers test of screened representative products by performing PCA and AHC on sensory data,can be verified mutually.It is helpful to understand the needs of consumer segmentations and reason to buy by combining sensory data and consumer test.

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.

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.

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.

Ultralight 3D-γ-MnOOH porous materials fabricated by hydrothermal treatment and freeze-drying

Creating three-dimensional(3D) ultralight metal oxide using cost-effective precursors and facile approaches is important. Here, shape-controlled γ-MnOOH(density lower than 0.078 g cm-3) with a continuously 3D porous network(3D-γ-MnOOH) was successfully fabricated with KMnO4, MnCl2 and NaOH via hydrothermal treatment and freeze-drying. The hydrothermal condition and the amount of reactants were systematically investigated, and the optimal procedure occurs at 180°C for 10 h with the molar ratios of NaOH/KMnO4 and MnCl2/KMnO4 as 5.0 and 3.5,respectively. Owing to the low density, 3D network, and the filling of air inside the channel, the new γ-MnOOH can float on the water for at least 4 months with complete structure.The formation and floating mechanism of the 3D-γ-MnOOH were also explored. This new 3D-γ-MnOOH could be utilized in oil absorption.

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.

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.

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 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.