Gradient Medium Research Articles

Bilateral Symmetric non-Euclidean multi-frequency invisibility

Light propagation in non-Euclidean geometry has become a hot topic in recent years, while transformation optics theory demonstrates unique advantages in this respect. A notable application of transformation optics in non-Euclidean space is non-Euclidean invisibility cloak which avoids the challenges of negative refraction and anisotropic materials. In this work, we propose another configuration for non-Euclidean invisibility, capable of achieving invisible across a wide spectrum. Using coordinate transformation, we convert this non-Euclidean invisibility into planar gradient medium and validate its effects through full wave simulations. We also discover that the corresponding gradient medium can further relax the material parameters. Our findings suggest diverse strategies for non-Euclidean invisibility and planar gradient media, potentially advancing optical invisibility and transformation optics in non-Euclidean spaces.

Eimeria falciformis extracellular vesicles differentially express host cell lncRNAs.

Long noncoding RNAs (lncRNAs) are regulatory transcripts during protozoan infections in the host intestinal epithelial cells (IECs). Apicomplexan Eimeria falciformis sporozoite extracellular vesicles (EVs) contain virulence factors that modulate host IECs pro-inflammatory genes and immune responses. In this study, E. falciformis sporozoites were made to interact with inactivated host cells, and the parasite EVs were separated from total secretome by ultracentrifugation and purified on density gradient medium. Dose-dependent bio-activity of E. falciformis EVs was investigated by RNA sequencing, functional annotation and quantitative PCR. It was found that E. falciformis EVs induced mRNA, circRNA, and lncRNA expressions in mouse IECs. Of 38, 217 lncRNAs assembled, 157 and 152 were upwardly and downwardly expressed respectively. Differentially expressed lncRNAs were associated with cytokines, pyroptosis, and immune signaling pathways including FoxO, NF-κB, MAPK, and TGF-β. In essence, E. falciformis EVs altered host cell RNA expressions during the interaction with host IECs. Also, differentially expressed lncRNAs are potential diagnostic transcripts during Eimeria infections.

Phosphatidylcholine and cholesterol-loaded-cyclodextrins can replace egg yolk in the cryopreservation of equine spermatozoa

In the horse breeding industry, cryopreservation of spermatozoa has become an integral aspect of modern-day protocols. To avoid sperm damage during the freezing process, freezing media containing egg yolk are used. Recently, urgency to find an alternative to egg yolk has been increased due to the prevalence of Avian Influenza Virus (AIV). In the UK, the World Organization for Animal Health reports that between July and December 2022, an AIV outbreak led to the death of 4.62 million birds (56.73 million globally), with substantial consequences for agriculture, environment and egg availability (WAHIS. 2023; https://wahis.woah.org/#/dashboard/qd-dashboard: Accessed: 12 January 2023). Recent research has also called into question the biosafety of egg yolk, with RNA from highly pathogenic and low pathogenic AIV found on and in eggs (Stephens.et.al. Avian Diseases. 2020; 64:143-148). The cryoprotectant potential of phosphatidylcholine, the main phospholipid in egg yolk, has been investigated in diluents used for cryopreservation of human spermatozoa with some success (Sicchieri.et.al. Translational Andrology and Urology. 2021; 10:397-407). The chemically defined origin and increased biosafety make phosphatidylcholine a desirable alternative to egg yolk for use in cryopreservation. Ejaculates from four horses (n=4) were frozen using four different freezing extenders: a reference medium containing egg yolk and 3% dimethylformamide (control) and media without egg yolk supplemented with 1.5mg/ml2-hydroxypropyl-β-cyclodextrin cholesterol complex, 3% dimethylformamide and either 2% (P1), 4% (P2) or 6% phosphatidylcholine (P3). Samples were diluted and centrifuged on a density gradient medium (1000xg’ for 20 minutes). The cell band was aspirated and resuspended (200 × 10⁶ cells/ml) with allotted treatment extender. Samples were packed into 0.25ml straws, cooled to 5˚C for 25 minutes, then frozen using a programmable freezing unit (IceCube14s, Minitube, Germany). Temperature of the straws was reduced from 4 ˚C to -143˚C in 9 minutes, after which they were plunged directly into liquid nitrogen (-196˚C). Viability was assessed using NucleoCounter® NC-100™. Total motility analyses were performed with computer assisted semen analysis (Hamilton Thorne, USA). No difference in post-thaw viability was found between any of the media tested (P>0.05). No difference in total motility was found between the control (36.75±1.93σM), P1 (29.25±3.82σM) or P2 media (19.5±6.35σM) (P>0.05). However, post-thaw total motility of sperm cryopreserved in P3 media (16±6.01σM) was lower than the control (P<0.05). Media supplemented with 2-4% phosphatidylcholine and 1.5mg/ml cholesterol was effective in limiting loss of total motility and membrane integrity of equine spermatozoa, establishing the need for further breeding trials into the use of phospholipids for egg yolk lipid replacement to improve biosafety. The authors wish to recognize the support of Tullis Matson and Stallion AI Services Ltd in this study.

Evolution of the theoretical description of the isoelectric focusing experiment: I. The path from Svensson's steady-state model to the current two-stage model of isoelectric focusing.

In 1961, Svensson described isoelectric focusing (IEF), the separation of ampholytic compounds in a stationary, natural pH gradient that was formed by passing current through a sucrose density gradient-stabilized ampholyte mixture in a constant cross-section apparatus, free of mixing. Stable pH gradients were formed as the electrophoretic transport built up a series of isoelectric ampholyte zones-the concentration of which decreased with their distance from the electrodes-and a diffusive flux which balanced the generating electrophoretic flux. When polyacrylamide gel replaced the sucrose density gradient as the stabilizing medium, the spatial and temporal stability of Svensson's pH gradient became lost, igniting a search for the explanation and mitigation of the loss. Over time, through a series of insightful suggestions, the currently held notion emerged that in the modern IEF experiment-where the carrier ampholyte (CA) mixture is placed between the anolyte- and catholyte-containing large-volume electrode vessels (open-system IEF)-a two-stage process operates that comprises a rapid first phase during which a linear pH gradient develops, and a subsequent slow, second stage, during which the pH gradient decays as isotachophoretic processes move the extreme pI CAs into the electrode vessels. Here we trace the development of the two-stage IEF model using quotes from the original publications and point out critical results that the IEF community should have embraced but missed. This manuscript sets the foundation for the companion papers, Parts 2 and 3, in which an alternative model, transient bidirectional isotachophoresis is presented to describe the open-system IEF experiment.

Effect of Oral Antidiabetic Drugs on Tuberculosis Risk and Treatment Outcomes: Systematic Review and Meta-Analysis.

Tuberculosis and diabetes mellitus are two global pandemics and rising public health problems. Recent studies suggest that oral antidiabetic drugs (OADs) could reduce the risk of tuberculosis and improve clinical outcomes. However, the evidence is controversial. Therefore, we aimed to assess the effect of OADs on the risk of tuberculosis and treatment outcomes. We systematically searched for six databases from inception to 31 August 2022. We followed a predefined PICO/PECO strategy and included two randomized controlled trials and sixteen observational studies. This study collects 1,109,660 participants, 908,211 diabetic patients, and at least 13,841 tuberculosis cases. Our results show that metformin decreases the risk of active tuberculosis by 40% (RR 0.60; 95% CI 0.47-0.77) in diabetic patients. In addition, metformin exhibits a dose-response gradient (medium doses reduce the risk of active tuberculosis by 45%, while high doses reduce this risk by 52%). On the other hand, DPP IV inhibitors increase the risk of active tuberculosis by 43% (RR 1.43; 95% CI 1.02-2.02). Subgroup analysis showed that study design and metformin dose accounted for the heterogeneity. We conclude that metformin significantly protects against active tuberculosis among diabetic patients. On the contrary, DPP IV inhibitors could increase the risk of developing active tuberculosis.

Non-Destructive Extraction and Separation of Nano- and Microplastics from Environmental Samples by Density Gradient Ultracentrifugation.

Nano-/microplastics (NMPs, particle diameter < 5 mm) are widespread emerging pollutants causing diverse impacts on organisms due to their sizes, shapes, and chemical properties. Despite the fast increase in NMP research, an effective method to separate and identify NMP types from environmental samples is still lacking. Here, we developed a simple and effective approach for the non-destructive extraction and separation of various types of NMPs from environmental samples by density gradient ultracentrifugation (DGU). For the first time, DGU was capable to separate various NMPs from the complex matrix with high selectivity (100%), purity (93%), and applicability. Through a gradually changing density of the density gradient medium by changing the concentrations or volumes of CsCl/water solution (from 0.00065 to 0.01989 g cm-3 mm-1), various NMPs (with particle sizes as little as 50 nm) could be extracted and separated from soil samples with high recovery (78.5-96.0%). We confirmed the effectiveness and compatibility of DGU through a correct identification of all types of NMPs separated from artificial soil samples with Raman spectroscopy, simultaneous thermal analysis (STA), and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS). DGU is compatible with all analytical processes compared to other existing methods with much less sample pretreatment time (0.5 h). Overall, DGU is an effective and cheap method (2.2 USD/sample) to separate NMPs from environmental samples such as soil and water and, hence, can facilitate research on NMPs related to terrestrial and marine environments as well as human health.

Waveguide properties of interface separating a photorefractive crystal with diffusion nonlinearity and an exponential graded-index medium

Waveguide properties of the planar interface between the photorefractive crystal with diffusion type of nonlinearity and exponential graded-index medium are described theoretically. The wave equation with complicated refractive index spatially distributed and intensity-dependent is proposed and its exact solutions are found, which describe the transverse magnetic waves of two types. Waves of first type decay monotonically into the media at the both sides from interface, and waves of the second type decay with oscillations into the photorefractive crystal. It is possible to achieve such localization of the wave by choosing the values of the parameters in such a way that the oscillation period becomes sufficiently large. It is shown that narrow localization of the second type waves can be achieved by choosing the values of the parameters in such a way that the oscillation period becomes sufficiently large. The waveguide modes, the order of which is determined by the number of the intensity maxima in the exponential graded-index medium, are obtained. The waveguide mode decays with oscillations in an exponentially gradient medium. It is shown that the transition between modes is carried out by increasing the characteristic thickness of the exponential graded-index layer. The total power flow is calculated and the possibility of redistributing wave energy between contacting media is investigated with its using.

Eimeria falciformis secretes extracellular vesicles to modulate proinflammatory response during interaction with mouse intestinal epithelial cells

BackgroundProtozoan parasite secretions can be triggered by various modified media and diverse physicochemical stressors. Equally, host-parasite interactions are known to co-opt the exchange and secretion of soluble biochemical components. Analysis of Eimeria falciformis sporozoite secretions in response to interaction with mouse intestinal epithelial cells (MIECs) may reveal parasite secretory motifs, protein composition and inflammatory activities of E. falciformis extracellular vesicles (EVs).MethodsEimeria falciformis sporozoites were allowed to interact with inactivated MIECs. Parasite secretions were separated into EV and vesicle-free (VF) fractions by discontinuous centrifugation and ultracentrifugation. Secreted EVs were purified in an iodixanol density gradient medium and the protein composition of both EV and VF fractions were analyzed by liquid chromatoraphy-tandem mass spectroscopy. The inflammatory activities of E. falciformis sporozoite EV on MIECs were then investigated.ResultsDuring the interaction of E. falciformis sporozoites with inactivated MIECs, the parasite secreted VF and vesicle-bound molecules. Eimeria falciformis vesicles are typical pathogenic protozoan EVs with a mean diameter of 264 ± 2 nm, and enclosed heat shock protein (Hsp) 70 as classical EV marker. Refractile body-associated aspartyl proteinase (or eimepsin), GAP45 and aminopeptidase were the main components of E. falciformis sporozoite EVs, while VF proteins include Hsp90, actin, Vps54 and kinases, among others. Proteomic data revealed that E. falciformis EV and VF proteins are aggregates of bioactive, antigenic and immunogenic molecules which act in concert for E. falciformis sporozoite motility, pathogenesis and survival. Moreover, in MIECs, E. falciformis EVs induced upregulation of gene expression and secretion of IL-1β, IL-6, IL-17, IL-18, MCP1 as well as pyroptosis-dependent caspase 11 and NLRP6 inflammasomes with the concomitant secretion of lactate dehydrogenase.ConclusionsEimeria falciformis sporozoite interaction with MIECs triggered the secretion of immunogenic and antigenic proteins. In addition, E. falciformis sporozoite EVs constitute parasite-associated molecular pattern that induced inflammatory response and cell death. This study offers additional insight in the secretion and protein composition of E. falciformis secretomes as well as the proinflammatory functions of E. falciformis sporozoite EVs.Graphical

P-267 A continuous culture medium with a lower concentration of lactate has a pronounced effect on the percentage of usable blastocysts on day 5

Abstract Study question Does Continuous Single Culture Medium NX, an embryo culture medium containing 1mM lactate, support increased blastocyst development over high lactate Vitrolife G1/G2 Series sequential culture? Summary answer There is a statistically significant increase in day 5 usable blastocysts in low lactate culture medium compared to the one with high lactate medium. What is known already Studies have shown that day 5 is the most desirable day to obtain blastocysts that are of an expansion, grade and quality to be utilized for transfer and/or vitrification procedures as those result in the highest success of clinical pregnancy,as compared to day 6/ 7 blastocysts, that do not meet criteria. Moreover, recent studies have indicated that there is an increase in chromosomal correctness of embryos cultured in a 1mM lactate environment as opposed to the higher 6-10mM lactate concentrations that have historically been believed necessary for successful blastocyst culture and resulting pregnancy. Study design, size, duration A prospective split sibling oocytes study was performed on 50 ICSI and IMSI cycles from October 2020 through April 2021. Oocytes were divided into the low lactate medium and high lactate gradient medium immediately following ICSI/IMSI and thereafter cultured in those medium until the final day of blastocyst culture. All patient ages were included in the sample population. Participants/materials, setting, methods This study was carried out in a private clinic. All patient stimulation protocol information and diagnosis’ were recorded; however, there was no restriction on participation. The endpoint was to analyse the resulting usable blastocyst rates on day 5 and day 6 in both arms of the study, using a denominator of normal 2PN fertilization. If a blastocyst was transferred or cryopreserved on day 5 or day 6, it was determined to be usable. Main results and the role of chance The resulting data was stratified not only by day 5 and day 6 usable blastocyst rates but also by patient age. It illustrates a statistically significant improvement in day 5 usable blastocysts for patients &amp;lt;35 in CSCM-NXC vs G1/G2 at 56% and 42%, respectively, a 14% increase (p &amp;lt; .05). The overall day 5 usable blastocyst rate was also statistically significant in CSCM-NXC (47%) as compared to G1/G2 (36%), (p &amp;lt; .05) with all ages considered. Additionally, on day 5, there was a higher percentage of usable blastocysts demonstrated in low lactate vs high in patients aged 35-37 (65% vs 42%, respectively) and 41-42 (41% vs 15%). Statistical significance was reversed in patients &amp;lt;35 on day 6, with G1/G2 having 24% usable blasts and CSCM-NXC 10% (p &amp;lt; .05). Interestingly, though not significant, G1/G2 had an increase in usable blastocyst percentage on day 5 in patients &amp;gt;42 (20% vs 11%), but overall, CSCM-NXC saw an increase in that same age group by 16%. Limitations, reasons for caution Though statistical significance was found in this study, a greater number will help to bolster the statistical power of the observations. Additionally, more studies are needed in order to ascertain if low lactate has an effect on the development prior to ICSI and resulting culture. Wider implications of the findings The mechanism of action that leads to the successful embryo development in low lactate embryo culture medium is vastly unknown, so further studies are required in order to understand the complexities and the impact of the observations provided. Trial registration number not applicable.

Polymethyl(1-Butyric acidyl)silane-Assisted Dispersion and Density Gradient Ultracentrifugation Separation of Single-Walled Carbon Nanotubes.

Individual single–walled carbon nanotubes (SWNTs) with distinct electronic types are crucial for the fabrication of SWNTs–based electronic and magnetic devices. Herein, the water–soluble polymethyl(1–butyric acidyl)silane (BA–PMS) was synthesized via the hydrosilylation reaction between 3–butenoic acid and polymethylsilane catalyzed by 2,2′–azodibutyronitrile. As a new dispersant, BA–PMS displayed a quite good dispersing capacity to arc–discharged SWNTs and moderate selectivity for metallic species. The application of sucrose–DGU, the density gradient ultracentrifugation with sucrose as the gradient medium, to the co–surfactants (BA–PMS and sodium dodecyl sulfonate) individually dispersed SWNTs yielded metallic SWNTs of 85.6% purity and semiconducting SWNTs of 99% purity, respectively. This work paves a path to the DGU separation of the SWNTs dispersed by polymer–based dispersants with hydrophobic alkyl chains.

The Effect of Various Stimulants on Cytokine Secretion Profiles in Freshly Isolated Peripheral Blood Mononuclear Cells (PBMC)

Abstract Cytokines play critical roles in in cancer, in regulating autoimmune diseases and in chemically induced tissue damage repair. In response to antibody treatment or as a result of corona virus disease (COVID), a cytokine storm may occur where high levels of inflammatory cytokines are produced leading to organ damage. To understand how to regulate cytokine levels, primary cell in vitro assays may assess the effects of small molecule compounds or antibodies. We evaluated OKT3, Polyinosinic-polycytidylic acid (Poly I:C), Resiquimod, CpG oligodeoxynucleotides (CpG ODN), DynaBeads with aCD3/aCD28, Phytohemagglutinin (PHA)-M and lipoplolysaccharide (LPS) on cytokine secretion from 6 normal donors. PBMCs isolated from fresh blood using a density gradient medium were plated at 1 × 105 cells per well in the presence and absence of the test compounds for 48 hours. Supernatants were assessed for interleukin 2 (IL-2), tumor necrosis factor-α (TNFα) and interferon-γ (IFNγ). The remaining cells were assessed for viability to evaluate cytotoxicity. Flow cytometric profiles of T cell subsets were determined. The data generated from the 6 normal donors varied greatly, though the effects of the stimulants followed the same trends. The Dynabeads (CD3/28) generated the highest values of IL-2, IFNγ and TNFα in all donors. OKT3 and PHA-M, Resiquimod and LPS generated lesser amounts of the cytokines whereas Poly I:C and CpG ODN did not induce these cytokines over background levels. Only PHA-M caused a decrease in cell viability. Additionally, the release of cytokines was not associated with activation of T cells. Cytokine release assays provide a robust readout with certain stimuli and may facilitate evaluation of novel test compounds for functional activity.

Ejaculate parameters and the results of &lt;i&gt;in vitro &lt;/i&gt; fertilization treatment in infertile couples with overweight and obese men

BACKGROUND: Infertility and obesity are actual and at the same time occurring problems of many couples. Conflicting data have been obtained on ejaculate parameters and the results of infertility treatment using in vitro fertilization treatment (IVF) in overweight and obese men.&#x0D; AIM: To evaluate the results of examination and treatment using ART, depending on the body mass index (BMI) of men in infertile couples.&#x0D; MATERIALS AND METHODS: A retrospective analysis of the results of treatment at the International Center for Reproductive Medicine in 368 infertile couples was carried out. The mean age of men and women was 36.4 6.2 and 33.9 5 years, respectively. Previous treatment for varicocele, sexually transmitted infections, prostatitis and cryptorchidism was performed in 58 (15.7%), 43 (11.7%), 42 (11.4%) and 11 (2.9%) men, respectively. Height and weight were measured for all patients, and BMI was calculated. The ejaculate was processed using a gradient medium (SupraSperm, Origio), IVF or ICSI were used in 110 (29.9%) and 258 (70.1%) couples, respectively, signs of good embryo quality were determined according to recommendations of professional societies for reproductive medicine. The onset of pregnancy was confirmed by the results of ultrasound sonography of the uterus. The results were subjected to statistical analysis.&#x0D; RESULTS: The BMI mean was 27.4 4.4 kg/m2, overweight and obesity of the 1st and 2nd degrees were observed in 161 (43%), 58 (15.8%) and 23 (7%) men respectively. Higher BMI values of men corresponded to higher BMI values of women (p 0.001), BMI values did not depend on ejaculate volume, concentration, total number and number of motile spermatozoa, proportion of high-quality embryos, and pregnancy rate. The highest pregnancy rate was noted after treatment of couples with younger women and higher values of the total number, concentration and number of progressively motile spermatozoa and ejaculate volume (p = 0.037, p = 0.028, p 0.001, p = 0.003, p 0.0001, respectively).&#x0D; CONCLUSIONS: Overweight and obese men prevail in infertile couples seeking IVF treatment. IVF treatment can overcome infertility in couples with overweight and obese men.

Do it yourself! – Initial experiences with self-synthesized CsTFA for RNA-SIP analyses

Cesium trifluoroacetate (CsTFA) is a gradient medium for isopycnic centrifugation in RNA-based Stable Isotope Probing (RNA-SIP), an important means to link the structure and function of microbial communities. We report a protocol to easily synthesize CsTFA from cesium carbonate (Cs2CO3) and trifluoroacetic acid (TFA) and show that self-synthesized CsTFA performs similarly to commercial CsTFA in the separation of isotopically labelled and unlabelled bacterial RNA.

Non-heat-stressed Method to Isolate Hepatic Stellate Cells From Highly Steatotic Tumor-bearing Liver Using CD49a.

Non-heat-stressed Method to Isolate Hepatic Stellate Cells From Highly Steatotic Tumor-bearing Liver Using CD49a.

The composite planar waveguide structure consisting of the linearly graded-index layer and the nonlinear layer formed with an increasing the electric field

The new type of the composite planar waveguide characterized by unique optical properties caused by the special selection of the waveguide layers is described. The interface between linearly graded-index layer and medium characterized by a sharp appearance of self-focusing Kerr type nonlinear response is considered. The nonlinear surface wave propagating along the interface is obtained analytically as exact solution to the wave equation with dielectric function depending on across interface coordinate and electric field. The possibility of controlling the redistribution of wave energy between layers along the waveguide with an increase in the effective refractive index and the characteristic distance of the gradient medium is shown.

Staphylococcus-Induced Bacteriospermia In Vitro: Consequences on the Bovine Spermatozoa Quality, Extracellular Calcium and Magnesium Content.

Bacterial contamination of bovine ejaculates intended for artificial insemination may be reflected in a significant economic loss due to unsuccessful fertilization as well as health issues of the recipients. The Staphylococcus genus represents a large part of bacteriocenosis of bovine ejaculates. Therefore, this study aims to get a closer look on the effects of Staphylococcus-induced bacteriospermia under in vitro conditions on bovine sperm quality. Prior to inducing bacteriospermia, spermatozoa were separated from each ejaculate using Percoll® Plus gradient medium in order to limit the effects only to the selected bacterial species. Seven Staphylococcus species previously isolated from bovine semen were used for our experiments at a turbidity of 0.5 McFarland (equivalent to 1.5 × 108 colony-forming units per mL). The contaminated semen samples were incubated at 37 °C and at times of 0, 2, and 4 h, motility, mitochondrial membrane potential, reactive oxygen species (ROS) generation, sperm DNA fragmentation, and magnesium (Mg) and calcium (Ca) extracellular concentration were analyzed and compared with the control group (uncontaminated). The results showed no significant changes at the initial measurement. However, significant adverse effects were observed after 2 h and 4 h of incubation. Most notably, the presence of S. aureus, S. warneri, S. kloosii, and S. cohnii caused a significantly increased ROS production, leading to sperm DNA fragmentation, changes in the mitochondrial membrane potential, and a decreased sperm motility. Furthermore, the presence of Staphylococcus species led to lower extracellular concentrations of Mg and Ca. In conclusion, the overgrowth of Staphylococcus bacteria in bovine semen may contribute to oxidative stress resulting in sperm DNA fragmentation, altered mitochondrial membrane potential, and diminished sperm motility.

Blood Divider for Simple, Surface Tension‐Based Isolation of Peripheral Blood Mononuclear Cells

AbstractPeripheral blood mononuclear cell (PBMC) separation is routinely performed by centrifugation with a density gradient medium, and is essential for immunological research and clinical applications. PBMC separation highly relies on laborious, time‐consuming blood layering and PBMC collection by careful pipetting. Current methods to address this problem use a physical barrier formed between the separation medium and a blood sample to avoid the need for delicate pipetting, but still pose a risk of red blood cell (RBC) contamination. Here, a blood divider (B‐DV) is proposed as a centrifuge tube insert that allows blood cells to pass through a separation medium in one direction, while blocking fluid passage in the opposite direction and thus preventing RBC contamination during PBMC harvest. The B‐DV is a 3D‐printed mesh in which a fluid can divide into two, above and below the mesh face as soon as inverting the centrifuge tube. Such complete fluid division enables minimizing the volume of the separation medium to the extent of RBC volume to be packed, thus reducing the sedimentation distance for RBCs, and facilitating rapid PBMC isolation by simple tube inverting. This technology enables rapid, easy PBMC separation without user‐to‐user variability on PBMC separation efficiencies.

Local material symmetry group for first- and second-order strain gradient fluids

Using an unified approach based on the local material symmetry group introduced for general first- and second-order strain gradient elastic media, we analyze the constitutive equations of strain gradient fluids. For the strain gradient medium there exists a strain energy density dependent on first- and higher-order gradients of placement vector, whereas for fluids a strain energy depends on a current mass density and its gradients. Both models found applications to modeling of materials with complex inner structure such as beam-lattice metamaterials and fluids at small scales. The local material symmetry group is formed through such transformations of a reference placement which cannot be experimentally detected within the considered material model. We show that considering maximal symmetry group, i.e. material with strain energy that is independent of the choice of a reference placement, one comes to the constitutive equations of gradient fluids introduced independently on general strain gradient continua.

Development polymeric micellar system for targeted delivery of antitumor drugs

Asymmetric block copolymers PAAc-b-PAAm (DBC) and PAAm-b-PAAc-b-PAAm (TBC) comprised poly(acrylic acid) and polyacrylamide have been evaluated as potential vehicles for doxorubicin (Dox) targeted delivery. The processes of Dox release from the DBC and TBC micelles under the influence of the drug’s concentration gradient and various surrounding medium, such as NaCl solution and aqueous medium at pH= 5.75 and 9, were examined. The previously established tendency to significantly reduce the Dox encapsulation degree by the DBC and TBC micelles at the increase of the size of their “corona” was fully confirmed (Kunitskaya et al. 2018). Noticed that PAAm block’s lengthening complicated the Dox release against all environments under study. It was revealed that micelles which easily and effectively encapsulate Dox as easily "give away" the drug during dialysis. Increasing pH of the DBC and TBC solutions to 9 prevented drug release. It can be stipulated by enhancing interaction between Dox and micellar “core” caused by the ionization of –COOH groups contained in PAAc blocks. Preliminary biological investigations in vitro against human T-leukemia cells demonstrate essential anticancer activity of Dox/DBC and Dox/TDC compositions, as compared to pure Dox.

Separation of human granulocytes and mononuclear cells from whole blood using percoll on a centrifugal microfluidic disc

In this study, a new and robust strategy based on a lab-on-a-disc (LOD) platform for isolating human white blood cells (WBCs) from whole blood is presented. Fully automated disc performance is defined based on standard cell separation techniques with density gradient media (DGM). In this centrifugal microfluidic system, capillary and siphon valves' integration controls liquids' flow and handling. The one-step isolation process performed depends on the selective sedimentation on the percoll and no need for labeling. This pattern is achieved without any additional steps of extracellular filtration or cell lysis by optimizing the concentration of percoll media and centrifuge conditions. Five percoll media in the density range of 1.058–1.095 g.ml−1 have made it possible to achieve a cell band with the desired recovery rate and purity. Sedimentation process performed using gradient media, 1.058–1.077, and 1.077–1.088 g.ml−1 at a purity rate of 83% and 96%, respectively, in mononuclear cells (MNCs) and neutrophils isolation has recorded. For having high purity in blood cell analysis, a gradient medium with a density of 1.088 instead of 1.095 g.ml−1 has been used. Thus, the level of red blood cells (RBCs) contamination in the isolated granulocyte layer is effectively reduced. The obtained data prove that cellular viability is maintained during the performed processes, and the number of dead cells is less than 10%. Therefore, the proposed microfluidic disc is the right candidate in a wide range of bioanalysis assays and clinical diagnostics with a meager amount of sample.