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AbstractStar-shaped six-arm polymers with arms of the block copolymers of poly-2-ethyl-2-oxazine and poly-2-isopropyl-2-oxazine were synthesized. The branching center was hexaase[26]cyclophane. The prepared samples differed in the order of block attachment to the core. Molar masses of the two samples were 14200 and 21500 g⋅mol−1. The fractions of poly-2-ethyl-2-oxazine monomers in the arms were 61 and 65%, respectively. It was shown that the arms were strongly folded. Water-salt solutions of the star-shaped block copolymers exhibited thermoresponsiveness. The difference in the phase separation temperatures for the studied samples was caused by the differences in their molar masses and the different contents of poly-2-ethyl- and poly-2-isopropyl-2-oxazine blocks. The concentration dependences of the phase separation temperatures for the synthesized star-shaped copolymers coincided with those for the arms, despite the fact that the molecular masses of the stars and their arms differed by factor of near 6. The addition of NaCl to the aqueous of solutions of the star copolymers did not lead to significant changes in their characteristics. No influence of the order of the block attachment to the core on the molecule conformation and on the thermoresponsive behavior was found. [ABSTRACT FROM AUTHOR]

The ionic association of Alcian Blue dye with poly(styrene sulfonate) in aqueous solutions was studied for analytical purposes. The quadruple-charged cationic dye, Alcian Blue, was found to form colloidal ionic associates with poly(styrene sulfonate) anions. When the amounts of opposite charges are nearly equal, the resulting ionic associates lose solubility and coagulate rapidly. This effect occurs within a narrow range of the ratio of poly(styrene sulfonate) to Alcian Blue. At the point of charge equivalence, the zeta potential of the resulting particles is zero, which facilitates flocculation. The resulting flocs enlarge to approximately 0.05–0.5 mm and precipitate rapidly. FTIR spectroscopy confirms that the precipitate contains both poly(styrene sulfonate) and Alcian Blue dye. Sedimentation kinetics was studied in detail using scanning turbidimetry. Due to the high molar absorbance of the Alcian Blue dye at 600 nm, the point of equimolar charge ratio was precisely determined by spectrophotometry. The complete precipitation of ionic associates occurs when the amount of poly(styrene sulfonate) ranges from 1.4 to 1.55 mmol per 1 g of Alcian Blue dye. Such a narrow coagulation range allows for the use of the studied effect for quantitative analysis. Both Alcian Blue dye and poly(styrene sulfonate) can be quantified if one of their concentrations is known. [ABSTRACT FROM AUTHOR]

Monitoring soil rapidly available potassium (RAK) reserves is extremely significant for developing precise fertilizer recommendations. The sodium tetraphenylborate (NaBPh4)-spectrophotometer method is applied to the detection of soil RAK content as a speedy, efficient and portable approach. However, the detection accuracy of this method is inferior to the ammonium acetate (NH4OAc)-flame photometer method. Here, the detection processes of the NaBPh4 turbidimetry were optimized to find the correlation with the NH4OAc method, further discussed the reasons for the different results by the two methods. The maximum relative error is 13% after conversion through the calibration curve. In addition, the accuracy of the calibration curve was verified by selecting non-fitting soil samples from two experimental sites. Therefore, our work proposes that the NaBPh4 turbidimetry, more convenient and rapid, can accurately detect the soil RAK content in the field. It provides an experimental guidance for the detection method of soil RAK content based on ultraviolet detection and on-site rapid detection devices. [ABSTRACT FROM AUTHOR]

Serological tests of non-treponemal and treponemal types are the most frequently used for syphilis diagnosis. Nontreponemal tests are used to monitor disease activity. Toluidine red unheated serum test (TRUST), as one of nontreponemal tests, is generally applicable to hospitals at different levels. However, accurate judgment of TRUST results is inseparable from an experienced and accurate operator. To reduce current shortcomings of manual TRUST method, we attempted to convert the manual TRUST test into automatic TRUST test, that is, to determine the degree of aggregation of toluidine red particles by detecting the absorbance value of serum after reaction with toluidine red particles. 50 μL of serum sample and 80 μL toluidine red particles were added to 96-well plate. Then, the 96-well plate was placed on a microplate reader at medium grade for 8 min to mix. Then, plasma reagin reacted with toluidine red particles and promoted the aggregation of toluidine red particles to form a large clot, which eventually caused a decrease in the absorbance at 540 nm. The results showed that the specificity of the automatic TRUST test was 100%, the sensitivity was 87%. And this method showed 93.5% correlation with manual TRUST test. The developed method is simple and involves less subjectivity in reading results, opening new avenues for syphilis diagnostic testing. Turbidimetric immunoassay can avoid the shortcomings of subjective interpretation, time-consuming and manual operation of manual TRUST method, and is more suitable for large-scale screening in health examination. [ABSTRACT FROM AUTHOR]

The review primarily considers the scientific progress in the identification of impurities, molecular compounds, and heterophase inclusions in high-purity sulfur. Methods for their determination, established by the present time, based on atomic emission spectrometry, mass spectrometry, colorimetry, gravimetry, titrimetry, turbidimetry, conductometry, gas chromatography, infrared spectrometry, chromatography–mass spectrometry, and laser ultramicroscopy are thoroughly characterized. [ABSTRACT FROM AUTHOR]

It is shown that a more than significant amount of experimental data obtained in the field of studying systems based on thermosensitive hydrophilic polymers and reflected in the literature over the past decades makes the issue of their systematization and classification relevant. This, in turn, makes relevant the question of choosing the appropriate classification criteria. It is shown that the basic classification feature can be the number of phase transition stages, which can vary from one to four or more depending on the nature of the temperature-sensitive system. In this work, the method of inverse phase portraits is proposed for the first time. It was intended, among other things, to identify the number of phase transition stages. Moreover, the accuracy of this method significantly exceeds the accuracy of the previously used method of direct phase portraits since, for the first time, the operation of numerical differentiation is replaced by the operation of numerical integration. A specific example of the application of the proposed method for the analysis of a previously studied temperature-sensitive system is presented. It is shown that this method also allows for a quantitative comparison between the results obtained by the differential calorimetry method and the turbidimetry method. Issues related to increasing the resolution of the method of direct phase portraits are discussed. [ABSTRACT FROM AUTHOR]

In this study, the relationship between known inflammatory markers and serum biotidinase activity in multiple sclerosis (MS) patients was evaluated. This study was conducted between June 2022 and December 2022 in a tertiary referral hospital. MS patients with active infection, end-stage disease, malignancy, and trauma or infection in the last month were excluded. Complete blood count was performed by automated hematology analyzer, C-reactive protein (CRP) was determined by turbidimetric method with serum sample, and serum biotidinase activity was studied by enzymatic spectrophotometric method. The relationship between neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), CRP, immature granulocyte (IG) percentage, and serum biotidinase activity were evaluated with Spearman correlation analysis. A total of 126 patients (mean age was 36.5±9.2 years) were included in our study, and 86 of them (68%) were female. Eighty-four patients (66%) had low biotidinase activity. The patients with low and normal biotidinase activity were compared and there was no significant difference between age, NLR, PLR, CRP levels, and incidence of optic neuritis and myelitis (p=0.509, p=0.548, p=0.883, p=0.911, p=0.403, p=0.892 respectively). By Spearman's correlation analysis, there was no significant correlation between biotidinase activity and CRP, IG percentage, NLR and PLR. A significant correlation was found between NLR with PLR and IG [(p<0.001, r=0.756); (p=0.007, r=0.245), respectively]. This study suggests that biotidinase activity is not an inflammatory enzyme. More comprehensive prospective studies are needed on this subject. [ABSTRACT FROM AUTHOR]

Abstract Background Understanding thiamin (thiamine; vitamin B1) metabolism in plants is crucial, as it impacts plant nutritional value as well as stress tolerance. Studies aimed at elucidating novel aspects of thiamin in plants rely on adequate assessment of thiamin content. Mass spectrometry-based methods provide reliable quantification of thiamin as well as closely related biomolecules. However, these techniques require expensive equipment and expertise. Microbiological turbidimetric assays can evaluate the presence of thiamin in a given sample, only requiring low-cost, standard lab equipment. Although these microbiological assays do not reach the accuracy provided by mass spectrometry-based methods, the ease with which they can be deployed in an inexpensive and high-throughput manner, makes them a favorable method in many circumstances. However, the thiamin research field could benefit from a detailed step-by-step protocol to perform such assays as well as a further assessment of its potential and limitations. Results Here, we show that the Saccharomyces cerevisiae thiamin biosynthesis mutant thi6 is an ideal candidate to be implemented in a turbidimetric assay aimed at assessing the content of thiamin and its phosphorylated equivalents (total vitamer B1). An optimized protocol was generated, adapted from a previously established microbiological assay using the thi4 mutant. A step-by-step guidance for this protocol is presented. Furthermore, the applicability of the assay is illustrated by assessment of different samples, including plant as well as non-plant materials. In doing so, our work provides an extension of the applicability of the microbiological assay on top of providing important considerations upon implementing the protocol. Conclusions An inexpensive, user-friendly protocol, including step-by-step guidance, which allows adequate estimation of vitamer B1 content of samples, is provided. The method is well-suited to screen materials to identify altered vitamer B1 content, such as in metabolic engineering or screening of germplasm.

Background: Understanding thiamin (thiamine; vitamin B1) metabolism in plants is crucial, as it impacts plant nutritional value as well as stress tolerance. Studies aimed at elucidating novel aspects of thiamin in plants rely on adequate assessment of thiamin content. Mass spectrometry-based methods provide reliable quantification of thiamin as well as closely related biomolecules. However, these techniques require expensive equipment and expertise. Microbiological turbidimetric assays can evaluate the presence of thiamin in a given sample, only requiring low-cost, standard lab equipment. Although these microbiological assays do not reach the accuracy provided by mass spectrometry-based methods, the ease with which they can be deployed in an inexpensive and high-throughput manner, makes them a favorable method in many circumstances. However, the thiamin research field could benefit from a detailed step-by-step protocol to perform such assays as well as a further assessment of its potential and limitations. Results: Here, we show that the Saccharomyces cerevisiae thiamin biosynthesis mutant thi6 is an ideal candidate to be implemented in a turbidimetric assay aimed at assessing the content of thiamin and its phosphorylated equivalents (total vitamer B1). An optimized protocol was generated, adapted from a previously established microbiological assay using the thi4 mutant. A step-by-step guidance for this protocol is presented. Furthermore, the applicability of the assay is illustrated by assessment of different samples, including plant as well as non-plant materials. In doing so, our work provides an extension of the applicability of the microbiological assay on top of providing important considerations upon implementing the protocol. Conclusions: An inexpensive, user-friendly protocol, including step-by-step guidance, which allows adequate estimation of vitamer B1 content of samples, is provided. The method is well-suited to screen materials to identify altered vitamer B1 content, such as in metabolic engineering or screening of germplasm. [ABSTRACT FROM AUTHOR]

A broad spectrum of application fields, including human and animal health, food safety and environmental monitoring, require performing real time, on-field chemical determinations, a concept known as point-of-need testing (PONT). In the case of infectious diseases, it allows for early diagnosis, which usually enables better treatment options for the patient, and permits early outbreak detection and intervention with proper control measures. PONT solutions are usually developed on microfluidic chips, preferably with no extra equipment, as to lower their cost, ease their delivery and portability. However, equipment-free PONT is not always feasible, since off-chip operations (e.g., pumping or heating) might be required and provided by the so-called analyzers. A typical example is the hardware for optical reading, which is the subject of this perspective article. Firstly, the state-of-the-art is briefly analyzed considering the solutions provided by both academy and industry. Special emphasis is made on the smartphone-based approaches that use no additional hardware (add-ons) for optical reading. Smartphones are the straightforward option, since they can replace a number of operations typically done by analyzers. The issues arising from using smartphones without add-ons are classified into variability sources and technical challenges. Finally, a set of methods for dealing with these challenges is proposed and briefly discussed. Simpler systems will be more easily adopted by more users, for a broader range of application cases, and will let PONT be a more powerful tool for improving disease diagnosis and outbreak management. [ABSTRACT FROM AUTHOR]

This work presents the first development of an analytical turbidimetric method for the determination of legal alcohols in alcohol-based hand sanitizer products. A typical iodoform reaction is exploited to form a yellow product in the form of precipitates. An iodoform test shows a positive result as yellow precipitates in the presence of ethanol and isopropanol; therefore, the test can only be used to distinguish between methanol and those legal alcohols. In the presence of molecular iodine (I2) and a strong alkaline solution, the legal alcohol is converted to the corresponding carbonyl compound (i.e., ethanol to acetaldehyde, isopropanol to acetone). The susceptibility of this intermediate towards the reaction with hydroxide ions (strong alkaline condition) results in formations of yellow precipitation of iodoform (CHI3) and a water-soluble carboxylate salt in the solution. Therefore, this change allows for the detection of legal alcohols through either naked-eye observation (as semi-quantitative analysis) or a common benchtop/portable photometer/spectrophotometer (as quantitative analysis) by means of turbidimetric analysis. In this work, turbidimetry is employed, which is a useful alternative detection method in analytical practice, especially with colored samples in hand sanitizing products. This is because they can employ wavelengths at which the colored solution does not absorb light. As a result of our developed method, the calibration plots are in the range of 30 to 100% (v/v) for both ethanol and isopropanol. The limit of detection (LOD) (3SD of y-intercept/slope) was found to be 7.4% (v/v) ethanol and 6.5% (v/v) isopropanol. Direct analysis of the non-pretreatment of the sample is achieved. The results indicate that our new proposed analytical method is fit for purpose and valid to detect the legal alcohols in alcohol-based hand sanitizing products for both international and Thai regulations (at least 70% (v/v)). Our quantitative results were also comparable to a standard analytical method, such as the use of a gas chromatography-flame ionization detector (GC-FID). Our developed method and analytical operation could potentially be developed into a practically portable analysis.

C1 inhibitor of serine proteases (C1-INH) performs a regulatory function in the complement system and vascular permeability. Deficiency of C1-INH leads to various forms of angioedema, including hereditary angioedema (HAE). The cause of HAE is a genetically determined violation of the synthesis of C1-INH. A decrease in the level of C1-INH to 50% relative to the norm leads to an increase in the production of bradykinin, which is the basis for the diagnosis of HAE. The development of affordable ELISA for the quantitative determination of C1-INH is a popular direction for clinicians. During the development of a new kit for quantitative determination of C1-INH, two mouse monoclonal antibodies (mAb) with different epitope specificities were obtained. On their basis, a sandwich-type ELISA was developed. The specificity of the obtained mAb's was confirmed using the medical device “Berinert”. To prepare calibrators, C1-INH was affinity purified from human blood plasma using a sorbent with immobilized mAbs. The identity of the C1-INH protein was confirmed by PAGE electrophoresis, immunoblotting, and mass spectrometry on MALDI-TOF/TOF UltrafleXtreme mass spectrometer. To assess the quality indicators of developed reagents kit, studies were carried out in accordance with GOST R 51352-2013 and TU 21.20.23-041-01967164-2022. Values of quality indicators: accuracy — 93.53%; measurement linearity interval — 22.00-176.07 ng/mL. Using the developed ELISA test system, we examined 28 blood sera from healthy donors and 7 blood sera from patients with confirmed HAE. In the same samples, the content of C1-INH was determined by turbidimetric method, using the "Diagnostic reagents for in vitro immunochemical studies of specific blood proteins. Model: C1-esterase inhibitor (C1 EsteraseInhibitor)" (Aptec, Belgium). The correlation coefficient was 0.94 (p < 0.05). It was found that the diagnostic sensitivity and specificity of the developed ELISA is 100%. As a result of the study, an original ELISA test system for the quantitative determination of C1-INH was developed "Reagent kit for enzyme-linked immunosorbent assay of human C1-inhibitor (C1-inh PS)".

A broad spectrum of application fields, including human and animal health, food safety and environmental monitoring, require performing real time, on-field chemical determinations, a concept known as point-of-need testing (PONT). In the case of infectious diseases, it allows for early diagnosis, which usually enables better treatment options for the patient, and permits early outbreak detection and intervention with proper control measures. PONT solutions are usually developed on microfluidic chips, preferably with no extra equipment, as to lower their cost, ease their delivery and portability. However, equipment-free PONT is not always feasible, since off-chip operations (e.g., pumping or heating) might be required and provided by the so-called analyzers. A typical example is the hardware for optical reading, which is the subject of this perspective article. Firstly, the state-of-the-art is briefly analyzed considering the solutions provided by both academy and industry. Special emphasis is made on the smartphone-based approaches that use no additional hardware (add-ons) for optical reading. Smartphones are the straightforward option, since they can replace a number of operations typically done by analyzers. The issues arising from using smartphones without add-ons are classified into variability sources and technical challenges. Finally, a set of methods for dealing with these challenges is proposed and briefly discussed. Simpler systems will be more easily adopted by more users, for a broader range of application cases, and will let PONT be a more powerful tool for improving disease diagnosis and outbreak management.

This work presents the first development of an analytical turbidimetric method for the determination of legal alcohols in alcohol-based hand sanitizer products. A typical iodoform reaction is exploited to form a yellow product in the form of precipitates. An iodoform test shows a positive result as yellow precipitates in the presence of ethanol and isopropanol; therefore, the test can only be used to distinguish between methanol and those legal alcohols. In the presence of molecular iodine (I2) and a strong alkaline solution, the legal alcohol is converted to the corresponding carbonyl compound (i.e., ethanol to acetaldehyde, isopropanol to acetone). The susceptibility of this intermediate towards the reaction with hydroxide ions (strong alkaline condition) results in formations of yellow precipitation of iodoform (CHI3) and a water-soluble carboxylate salt in the solution. Therefore, this change allows for the detection of legal alcohols through either naked-eye observation (as semi-quantitative analysis) or a common benchtop/portable photometer/spectrophotometer (as quantitative analysis) by means of turbidimetric analysis. In this work, turbidimetry is employed, which is a useful alternative detection method in analytical practice, especially with colored samples in hand sanitizing products. This is because they can employ wavelengths at which the colored solution does not absorb light. As a result of our developed method, the calibration plots are in the range of 30 to 100% (v/v) for both ethanol and isopropanol. The limit of detection (LOD) (3SD of y-intercept/slope) was found to be 7.4% (v/v) ethanol and 6.5% (v/v) isopropanol. Direct analysis of the non-pretreatment of the sample is achieved. The results indicate that our new proposed analytical method is fit for purpose and valid to detect the legal alcohols in alcohol-based hand sanitizing products for both international and Thai regulations (at least 70% (v/v)). Our quantitative results were also comparable to a standard analytical method, such as the use of a gas chromatography-flame ionization detector (GC-FID). Our developed method and analytical operation could potentially be developed into a practically portable analysis. [ABSTRACT FROM AUTHOR]

Background: Marbofloxacin (MAR) is an antimicrobial belonging to the fluoroquinolone class and is marketed in the form of tablets. There is no microbiological monograph in official compendia to evaluate the potency of the final product. Furthermore, the literature is scarce in this context. Objective: The objective is to develop and validate a microbiological method by turbidimetry to evaluate the potency of MAR-based tablets, based on the principles of green analytical chemistry. Methods: Purified water–ethanol (9 þ 1, v/v) was used as diluent to prepare the MAR solutions at concentrations of 0.25, 0.8, and 2.56 mg/mL, brain heart infusion (BHI) broth as culture media, E. coli American Type Culture Collection (ATCC) 25922 at 10% and incubation in a shaker at 37C for 4 h were used in the method. Results: The method was: linear in the range of 0.25 to 2.56 mg/mL; selective against the sample adjuvants; precise (intra-day RSD 2.26%, inter-day RSD 3.49%, and inter-analyst RSD 3.59%); accurate with a recovery of 100.20%; and robust against changes in culture medium volume in the tube, shaker rotation, and incubation temperature in the shaker. The potency of MAR tablets was 96.98% using the proposed method. Conclusion: The turbidimetric method developed is a new, fast, and optimized option to the routine QC of MAR in tablets, since it allows the evaluation of the drug’s potency in the final product and can be used to complement the results of the physicochemical analysis, in addition to being a green and sustainable alternative. Highlights: The work shows an ecological and green alternative to the routine microbiological pharmaceutical analysis of MAR tablets. [ABSTRACT FROM AUTHOR]

Aerobic vaginitis (AV) is a vaginal infection caused mainly by overgrowth of Escherichia coli and a reduction of Lactobacilli in the vagina. The infection is linked with adverse pregnancy outcomes, such as preterm birth. The current medical therapy for AV with antibiotics is associated with adverse effects and necessitates the use of alternative treatments. Apple cider vinegar (ACV) is a natural fermented product produced from apples and is reported to exhibit potent antibacterial activity. ACV also contains lactic acid bacteria, which can act as probiotics. Symptoms of AV can be improved by restoring the disturbed microbial imbalance rather than exposing the vagina to synthetic drugs. Hence, an attempt was made to investigate whether ACV could support growth of the beneficial bacteria and inhibit growth of the pathogenic bacteria such as E. coli in the vagina. In vitro evaluation of the anti-bacterial potential of ACV against E. coli showed a potent antibacterial activity, recording a zone of inhibition diameter of 32.9 ± 0.5 mm; however, no zone of inhibition was observed against Lactobacillus acidophilus. Turbidimetric analysis was used to ensure growth of the bacteria in a simulated vaginal fluid (SVF) by using a nephelometer as a Nephelometric Turbidity Unit (NTU). Both E. coli and L. acidophilus were grown individually in SVF containing ACV. The ACV expressed antibacterial efficacy against E. coli and favoured growth of L. acidophilus in the SVF. Conclusively, ACV can help in growth of the beneficial bacteria and restore the natural microbiota of the vagina, thus proving to be beneficial in the management of AV.

The aim of this paper is to examine the contribution of turbidimetry measurements in the characterisation of cement pastes bleeding. In some cases (e.g. the presence of superplasticiser), the bleed water becomes turbid due to dispersion of the finest particles, and the boundary between the bleed water and the consolidated paste becomes difficult to detect. A Turbiscan device allows this boundary to be detected more accurately than in traditional tests. The role of superplasticiser and solid volume fraction in bleeding is examined. The bleeding measurements highlight the role of the superplasticiser in bleeding and its kinetics. The effect of superplasticiser may be explained by better dispersion leading to the release of water trapped between agglomerates. Furthermore, the existence of a critical volume fraction is shown, above which no bleeding occurs, and close to that corresponding to the appearance of contacts between particles. Finally, using rheological measurements, the correlation between the yield stress and bleeding has been possible. [ABSTRACT FROM AUTHOR]

Thrombosis is responsible for thousands of deaths in a myriad of countries particularly the developed ones. Venous thrombosis incidents such as deep vein thrombosis and thromboembolism are the inevitable results of the contemporary lifestyle. In this article, we have designed a new family of tehtrahydro pyrido pyrimidines inspired by structures of antiplatelet agents reported in the literature. Furthermore, 13 derivatives of our lead compound N'-benzylidene-7-(4-methoxyphenyl)-2,4-dioxo-1,2,3,4-tetrahydropyrido[2,3-d]pyrimidine-5-carbohydrazide have been synthesized. The molecular docking study was conducted on COX-1 enzyme (pdb: 2oye), Compounds 8b and 8d had the most calculated binding energy with ΔG values of −8.41 and −7.74 Kcal/mol, sequentially. The platelet aggregometry inhibition effects of the synthesized compounds have been measured on the voluntarily donated human platelets using BORN turbidimetry method. Furthermore, compound 8d showed the most potency with the IC50 value of 16.9 and 37.41 µM on the ADP and AA inducers, respectively. Generally, all the compounds with electron-withdrawing substituents showed plausible activity against the ADP-inducing platelet aggregation. Besides, electron-withdrawing compounds in para position showed an acceptable inhibitory effect on the AA platelet inducer. [ABSTRACT FROM AUTHOR]

[Display omitted] The shape and quantity of hydrophilic silica nanoparticles (NPs) can be used to tune the microstructure, rheology, and stability of phase-separating polymer solutions. In thermoresponsive polymer systems, silica nanospheres are well-studied whereas anisotropic NPs have little literature precedent. Here, we hypothesize that NP shape and concentration lower the onset of rheological and turbidimetric transitions of aqueous poly(N-isopropyl acrylamide) (PNIPAM) solutions. Differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), turbidimetry, and oscillatory rheology are utilized to examine interactions between NPs, PNIPAM, and water and to track changes in phase separation and rheological properties due to NP concentration and shape. NP addition reduces phase separation enthalpy due to PNIPAM-NP hydrogen bonding interactions, the degree to which depends on polymer content. While NP addition minorly impacts thermodynamic and optical properties, rheological transitions and associated rheological properties are dramatically altered with increasing temperature, and depend on NP quantity, shape, and polymer molecular weight. Thus NP content and shape can be used to finely tune transition temperatures and mechanical properties for applications in stimuli-responsive materials. [ABSTRACT FROM AUTHOR]

Hemoglobin and glycosylated hemoglobin (HbA1C) are frequently monitored health indicators in population based studies for information about the status of nutrition and diabetes control. We present here possibly for the first time the findings of simultaneous estimation of Hemoglobin and HbA1C on Dried blood spot (DBS) samples by a single test. Validation was done by turbidimetric inhibition immunoassay (TINIA) using Roche Integra 400 plus instrument. Paired whole blood and DBS samples were tested for HbA1C estimation by Integra 400 plus. Total hemoglobin values obtained during HbA1C estimation were compared with hemoglobin values estimated by Coulter AcT 5 Diff CP Hematology counter. Agreement in HbA1C and hemoglobin values between paired whole blood and DBS samples was found to be high with R² values of 0.994 and 0.9349, respectively. Intra- and inter-assay precision was found to be within 10% for both parameters. Values obtained after assaying DBS samples prepared by spotting proficiency samples on Whatman 903 protein saver cards demonstrated acceptable standard deviation indices resulting in successful participation in EQAS programs for both these parameters. The results reveal the potential of TINIA for simultaneous estimation of hemoglobin and HbA1C from a single punch of the DBS samples. [ABSTRACT FROM AUTHOR]

Objective: To determine the effect of pasteurization and freezing on the content of IgA1 and IgA2 in breast Methods: Observational, retrospective study, carried out in women who had been breastfeeding their newborn for more than 30 days, and could donate 50 mL of milk. The concentration of IgA1 and IgA2 was determined by turbidimetry, before and after being subjected to pasteurization and freezing, every 15 days for 2 months. Freezing was at -20°C. A total IgA content of 1598.5 mg/dL was found. Results: 10 breast milk donors were selected. The initial concentration of IgA1 and IA2 was 651 and 945.7 mg/dL, respectively; At the end of the freezing times, the content of both immunoglobulins decreased: IgA1 of 74% and IgA2 of 86%. After the treatments, the immunoglobulin content decreased dramatically, with a significant difference of p < 0.05. Conclusion: Pasteurization and freezing significantly affect the content of IgA1 and IgA in breast milk; therefore, breast-feeding remains the best way to offer full immunological protection to the infant. [ABSTRACT FROM AUTHOR]

A polycondensation aromatic polyester with an oxygen spacer was synthesized and used as a macroinitiator for the grafting of linear poly(2-isopropyl-2-oxazoline) (PiPrOx) by the cationic polymerization method. The length of the thermosensitive side chains was varied by the initiator:monomer ratio. Using methods of molecular hydrodynamics, light scattering and turbidimetry, the copolymers were studied in organic solvents and in water. The molecular characteristics of the main chain and graft copolymers, the polymerization degree of side chains and their grafting density have been determined. The equilibrium rigidity of the macroinitiator and the conformations of grafted macromolecules were evaluated. In selective solvents, they take on a star-like conformation or aggregate depending on the degree of shielding of the main chain by side chains. The thermoresponsiveness of graft copolymers in aqueous solutions was studied, and their LCST were estimated. The results are compared with data for graft copolymers composed of PiPrOx side chains and flexible or rigid chain backbones of aromatic polyester type. [ABSTRACT FROM AUTHOR]

Regular and irregular molecular brushes with polydimethylsiloxane backbone and poly-2-isopropyl-2-oxazoline side chains have been synthesized. Prepared samples differed strongly in the side chain grafting density, namely, in the ratio of the lengths of spacer between the grafting points and the side chains. The hydrodynamic properties and molecular conformation of the synthesized grafted copolymers and their behavior in aqueous solutions on heating were studied by the methods of molecular hydrodynamics and optics. It was found that the regularity and the grafting density do not affect the molecular shape of the studied samples of molecular brushes in the selective solvent. On the contrary, the grafting density is one of the most important factors determining the thermoresponsivity of grafted copolymers. It was shown that in analyzing self-organization and LCST values in aqueous solutions of poly-2-isopropyl-2-oxazolines with complex architecture, many factors should be considered. First is the molar fraction of the hydrophobic fragment and the intramolecular density. It was found that molar mass is not a factor that greatly affects the phase transition temperature of poly-2-isopropyl-2-oxazolines solutions at a passage from one molecular architecture to another. [ABSTRACT FROM AUTHOR]

A comparative study was carried out on the thermal stability of ovotransferrins (OTrfs) from chicken, duck, guinea fowl, Japanese quail, ostrich and turkey by differential scanning calorimetry (DSC), differential scanning fluorimetry (DSF) and turbidimetry. The average temperature at the denaturation midpoint in DSC (TmDSC) was 42.8 ℃ at pH 4.0, 63.8 ℃ at pH 7.0 and 59.4 ℃ at pH 9.0, and the differences in the TmDSC values between chicken and the other poultry, except ostrich, were less than 3.5 ℃. The results of DSF were almost comparable to those of DSC. In an analysis of poultry OTrf solution turbidi ties, ostrich OTrf solution remained clear up to 95.0 ℃ at pH 4.0 and pH 8.0, while the others became turbid at around 40 ℃ at pH 4.0 and 60 ℃ at pH 8.0. Turkey, Japanese quail and duck OTrfs remained soluble at pH 9.0 up to 73.0 °C, 85.0 °C and 95.0 °C, respectively, though turbidity appeared up to 60 ℃ in the others. Such findings on the similarities and differences among poultry OTrfs should be significant for the utilization of poultry eggs other than chicken eggs since the thermal processes required for chicken egg products often depends on the behavior of heat-susceptible chicken OTrf. [ABSTRACT FROM AUTHOR]

The paper presents the results of in situ studies of marine particles of different nature using a submersible digital holographic camera (DHC) during the Arctic expedition. It also describes the features, performance specifications, and possibilities of the DHC and the DHC technology. The DHC technology can be used for noninvasive automatic evaluation of spatial and temporal characteristics of plankton, including the distribution of plankton concentrations. The comparison of quantitative analysis of zooplankton net samples and classification results using the DHC revealed that the error of the DHC classification of mesoplankton at the level of the main systematic orders was about 30%. The results of determining the data on the medium, such as water turbidity, according to the radiation shielding factor (degree) by the particles of the Suspension taxon using the DHC technology are presented; the prospects for studying the size of gas bubbles and their volume content according to the Bubble taxon data are shown. The use of holographic data for in situ point estimates is considered. [ABSTRACT FROM AUTHOR]

The conditions for the smart colorimetric determination of cetylpyridinium chloride and sodium dodecyl sulfate by reaction with Coomassie brilliant blue G (CBBG) have been proposed. The nature of the absorption and fluorescence spectra of aqueous solutions of CBBG as a function of acidity has been investigated. A variety of reagent forms and associations with ionic surfactants have been demonstrated. The composition of the associates formed in the CBBG–cationic surfactant system has been established. The increase in the analytical signal of the cationic surfactant and the stabilization of the colloid-chemical state of the system during reactions in the organized medium of the nonionic surfactant Triton X-100 has been demonstrated. These effects are realized through association in premicellar solutions and as a result of the solubilization of components in Triton X-100 micellar solutions. The addition of long-chain cationic surfactants to the reagent occurs with the replacement of the heteroatom proton. The absorption of CBBG–cationic surfactant associates solutions increases with the length of the cationic surfactant hydrocarbon chain. Ethanol additives decrease the aggregation of CBBG. The technique of cationic surfactant determination has been tested in the analysis of the pharmaceutical. The results show that the simplicity of analytical signal registration with satisfactory correctness and acceptably high sensitivity of determination is an advantage of the developed technique. [ABSTRACT FROM AUTHOR]

BACKGROUND: To overcome the limitations in the use of protein as an emulsifier, soy lecithin, a natural surfactant, was used along with whey protein isolate (WPI) to produce o/w emulsions containing cholecalciferol and α‐tocopherol. The physical stability of the emulsions prepared with WPI and varying concentrations of lecithin (0, 1, 2, and 3% w/w) was measured in different heat, pH, and ionic‐strength food environmental conditions. RESULTS: All emulsions were shown to be less than 250 nm in size and less than 0.3 in polydispersity index (PDI). The morphology of the emulsions was spherical, and the droplets of the emulsion containing lecithin were thicker and larger than those of the emulsion without lecithin (WPI_L0). After autoclaving, WPI_L0 increased in size from 197.8 ± 1.7 nm to 528.5 ± 28.4 nm, and the retention of cholecalciferol and α‐tocopherol decreased to 40.83 ± 0.63% and 49.68 ± 1.84%, respectively. At pH 5.5, near the isoelectric point of WPI, WPI_L0 increased in size due to aggregation, but emulsions containing lecithin remained stable at a PDI under 0.3. Turbiscan stability index of the emulsion prepared with WPI and 3% lecithin was the lowest, indicating good storage stability. In addition, it was confirmed that the higher the lecithin content, the higher the viscosity, and the higher the amount of free fatty acids released in the in vitro digestion model. CONCLUSION: This study can provide theoretical evidence for enhancing the physical stability of protein emulsions by co‐stabilization with lecithin, promoting their application in various foods. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background: Mechanisms by which chronic kidney disease (CKD) influences fibrin clot properties in atrial fibrillation (AF) remain ill-defined. We aimed to investigate the effects of AF and CKD on fibrin clot properties and lipoproteins, and determine the relationship between these factors. Methods: Prospective cross-sectional study of patients recruited from cardiology services in Liverpool between September 2019 and October 2021. Primary groups consisted of anticoagulated AF patients with and without CKD in a 1:1 ratio. Control group comprised anticoagulated patients without AF or CKD. Fibrin clot properties were analysed using turbidity and permeation assays. Detailed lipoprotein characteristics, including total cholesterol, low-density lipoprotein cholesterol (LDL-C), small dense LDL and oxidised LDL, were measured. Results: Fifty-six anticoagulated patients were enrolled (median age 72.5; 34% female); 46 with AF (23 with CKD and 23 without CKD) and 10 controls. AF was associated with changes in three indices of fibrin clot properties using PTT (Tlag 314 vs. 358 s, p = 0.047; Abspeak 0.153 vs. 0.111 units, p = 0.031; Tlysis50% 884 vs. 280 s, p = 0.047) and thrombin reagents (Tlag 170 vs. 132 s, p = 0.031; Tmax 590 vs. 462 s, p = 0.047; Tpeak50% 406 vs. 220 s, p = 0.005) while the concomitant presence of CKD led to changes in fibrin clot properties using kaolin (Tlag 1072 vs. 1640 s, p = 0.003; Tmax 1458 vs. 1962 s, p = 0.005; Tpeak50% 1294 vs. 2046, p = 0.008) and PPP reagents (Tlag 566 vs. 748 s, p = 0.044). Neither of these conditions were associated with changes in fibrin clot permeability. Deteriorating eGFR was significantly correlated to the speed of clot formation, and CKD was independently associated with unfavourable clot properties (Tlag −778, p = 0.002; Tmax −867, p = 0.004; Tpeak50% −853, p = 0.004 with kaolin reagent). AF alone was not associated with changes in lipoprotein distribution while AF patients with CKD had lower total cholesterol, LDL-C and small dense LDL due to the presence of other risk factors. No significant relationship was observed between fibrin clot properties and lipoprotein distribution. Conclusions: There are important changes that occur in fibrin clot properties with AF and CKD that may account for the increased risk of thromboembolic complications. However, these changes in fibrin clot properties were not attributable to alterations in lipoprotein distribution. [ABSTRACT FROM AUTHOR]

The mechanism of flocculation of silica hydrosol (Ludox TM-40) with polyacrylamide (Magnafloc brand) was studied by viscometry, turbidimetry, and dynamic light scattering (DLS). The existence of two stages of flocculation is shown: the formation of primary floccules according to the mechanism of heteroadagulation of silica nanoparticles on the surface of polymer microglobules and enlargement of polymer associates with the formation of sedimentation-unstable composite particles. The transition from the first step of the process to the second step is characterized by the value of the critical flocculation concentration (CCF). The intensity of flocculation increases with an increase in the molecular weight of polyacrylamide and the degree of hydrolysis of amide groups (anionic nature of the polymer). [ABSTRACT FROM AUTHOR]

Gypsum is widely found in soils under arid and semi-arid climates due to its semi-soluble nature. In spite of that, they are less known than other soils, and this has generated some misunderstandings in some initial pedological concepts and in soil classification systems. In addition, the quantification of gypsum, and in particular of its secondary accumulations is affected by the sampling procedures and sample handling in the lab; besides by the methods used for the determination of gypsum themselves, since they differ on the accuracy, cost, and expertise needed. The objective of our research is to improve some laboratory procedures in order to determine and quantify gypsum in the soil, especially secondary accumulations. We applied several methods of sample handling and gypsum analysis to a loess profile in the Ebro Valley (NE Iberia), consisting of 10 horizons containing gypsum in varying amounts (0 to about 50%); of different sizes and morphologies. We propose a protocol considering procedures (sieving or not), qualitative determinations and two methods (turbidimetry and dehydration of crystallization water) for an optimal determination of gypsum depending on the characteristics of the sample and compared them with the acetone method (US Salinity Laboratory Staff, Agric. Handb., 1954, 60, 175; Nelson, 1978, 181), as it is the reference method in the main Classification Systems. The results obtained after applying the different methods for the analysis of gypsum in bulk samples have allowed us to propose a decision tree procedure for the determination of gypsum in soil materials. This procedure includes, determination of gypsum in all fractions, coarse and fine, the estimated amount of gypsum in the field (as a major or minor component) and the presence of other components that may interfere with the results. The most accurate results are obtained with those methods based on the loss of gypsum water upon heating when gypsum content is >4%, and with the turbidimetric method in case of lower amounts of gypsum. Finally, we discuss the implications of these analyses when a soil is classified according to the main soil classification systems (WRB 2014; Soil Survey Staff, SSS- NRCS, 2014).

In this paper, the variation of suspension stability under the electric field was studied. Ceramic suspensions such as YSZ/acetyl acetone, YSZ/1propanol, and SnO2/ethanol were analyzed by applying different voltages. The novel turbidimetry technique was employed to illustrate the stability changes versus electrophoretic deposition (EPD) time. Macro-photography was employed to study the colloidal stability before and after EPD. Also, the weight of the deposited particles was measured. Particles in the suspension were sediment after applying voltage, making the suspension transparent in our deposition cell, especially at 100 V. The electrical conductivity of suspension increased by applying the electric field, showing a peak at 100 V. The suspension conductivity measurements also revealed a peak at 100 V. The occurred transparency became more in-depth over time. As suspension stability is an essential factor for a successful EPD process, the electric field-assisted agglomeration of particles should be considered in tests to reach repeatable results. Our research showed that despite the use of high voltage in routine EPD research, the instability of suspensions and its effect on the results of the coating should be considered. [ABSTRACT FROM AUTHOR]

Light scattering and turbidimetry techniques are classical tools for characterizing the dynamics and structure of single nanoparticles or nanostructured networks. They work by analyzing, as a function of time (Dynamic Light Scattering, DLS) or angles (Static Light Scattering, SLS), the light scattered by a sample, or measuring, as a function of the wavelength, the intensity scattered over the entire solid angle when the sample is illuminated with white light (Multi Wavelength Turbidimetry, MWT). Light scattering methods probe different length scales, in the ranges of ~ 5 – 500   nm (DLS), or ~ 0.1 – 5   μ m (Wide Angle SLS), or ~ 1 – 100   μ m (Low Angle SLS), and some of them can be operated in a time-resolved mode, with the possibility of characterizing not only stationary, but also aggregating, polymerizing, or self-assembling samples. Thus, the combined use of these techniques represents a powerful approach for studying systems characterized by very different length scales. In this work, we will review some typical applications of these methods, ranging from the field of colloidal fractal aggregation to the polymerization of biologic networks made of randomly entangled nanosized fibers. We will also discuss the opportunity of combining together different scattering techniques, emphasizing the advantages of a global analysis with respect to single-methods data processing. [ABSTRACT FROM AUTHOR]

Cataract is one of the most prevalent protein aggregation disorders and still the most common cause of vision loss worldwide. The metabolically quiescent core region of the human lens lacks cellular or protein turnover; it has therefore evolved remarkable mechanisms to resist light-scattering protein aggregation for a lifetime. We now report that one such mechanism involves an unusually abundant lens metabolite, myo-inositol, suppressing aggregation of lens crystallins. We quantified aggregation suppression using our previously well-characterized in vitro aggregation assays of oxidation-mimicking human γD-crystallin variants and investigated myo-inositol's molecular mechanism of action using solution NMR, negative-stain TEM, differential scanning fluorometry, thermal scanning Raman spectroscopy, turbidimetry in redox buffers, and free thiol quantitation. Unlike many known chemical chaperones, myo-inositol's primary target was not the native, unfolded, or final aggregated states of the protein; rather, we propose that it was the rate-limiting bimolecular step on the aggregation pathway. Given recent metabolomic evidence that it is severely depleted in human cataractous lenses compared to age-matched controls, we suggest that maintaining or restoring healthy levels of myo-inositol in the lens may be a simple, safe, and globally accessible strategy to prevent or delay lens opacification due to age-onset cataract. [ABSTRACT FROM AUTHOR]

Turbidimetry is an experimental technique often used to study the structure of filamentous networks. To extract structural properties such as filament diameter from turbidimetric data, simplifications to light scattering theory must be employed. In this work, we evaluate the applicability of three commonly utilized turbidimetric analysis approaches, each using slightly different simplifications. We make a specific application towards analyzing fibrin fibers, which form the structural scaffold of blood clots, but the results are generalizable. Numerical simulations were utilized to assess the applicability of each approach across a range of fiber lengths and diameters. Simulation results indicated that all three turbidimetric approaches commonly underestimate fiber diameter, and that the "Carr-Hermans" approach, utilizing wavelengths in the range of 500–800 nm, provided <10% error for the largest number of diameter/length combinations. These theoretical results were confirmed, under select conditions, via the comparison of fiber diameters extracted from experimental turbidimetric data, with diameters obtained using super-resolution microscopy. [ABSTRACT FROM AUTHOR]

Lytic polysaccharide monooxygenases (LPMOs) are widely distributed in fungi, and catalyze the oxidative degradation of polysaccharides such as cellulose. Despite their name, LPMOs possess a dominant peroxygenase activity that is reflected in high turnover numbers but also causes deactivation. We report on the influence of small molecules and ions on the activity and stability of LPMO during catalysis. Turbidimetric and photometric assays were used to identify LPMO inhibitors and measure their inhibitory effect. Selected inhibitors were employed to study LPMO activity and stability during cellulose depolymerization by HPLC and turbidimetry. It was found that the fungal metabolic products oxalic acid and citric acid strongly reduce LPMO activity, but also protect the enzyme from deactivation. QM calculations showed that the copper atom in the catalytic site could be ligated by bi- or tridentate chelating compounds, which replace two water molecules. MD simulations and QM calculations show that the most likely inhibition pattern is the competition between the inhibitor and reducing agent in the oxidized Cu(II) state. A correlation between the complexation energy and the IC50 values demonstrates that small, bidentate molecules interact strongest with the catalytic site copper and could be used by the fungus as physiological effectors to regulate LPMO activity. [ABSTRACT FROM AUTHOR]

The present investigation focuses on the analysis of the interactions among human lactoferrin (LF), SARS-CoV-2 receptor-binding domain (RBD) and human angiotensin-converting enzyme 2 (ACE2) receptor in order to assess possible mutual interactions that could provide a molecular basis of the reported preventative effect of lactoferrin against CoV-2 infection. In particular, kinetic and thermodynamic parameters for the pairwise interactions among the three proteins were measured via two independent techniques, biolayer interferometry and latex nanoparticle-enhanced turbidimetry. The results obtained clearly indicate that LF is able to bind the ACE2 receptor ectodomain with significantly high affinity, whereas no binding to the RBD was observed up to the maximum "physiological" lactoferrin concentration range. Lactoferrin, above 1 µM concentration, thus appears to directly interfere with RBD–ACE2 binding, bringing about a measurable, up to 300-fold increase of the KD value relative to RBD–ACE2 complex formation. [ABSTRACT FROM AUTHOR]

In the present scenario, food security is of major concern due to exponentially increasing population and depleted crop production. The fungal diseases have contributed majorly to the scarcity of staple food products and economic loss worldwide. This problem could be tackled by preventing the crop loss during both pre and post-harvest seasons. During the current investigation, the bioactive compound eicosane was extracted from Streptomyces sp. KF15, subjected to purification and identified based on mass spectrometry and NMR analysis. The evaluation of in-vitro antifungal activity was done by poisoned food method, SEM analysis and growth pattern analysis. The bioactive compound eicosane with molecular weight of 282.5475 g/mol was purified by column chromatography and the straight chain hydrocarbon structure of CH 3 CH 2(18) CH 3 was elucidated by NMR analysis. In poisoned food assay, eicosane effectively inhibited the radial growth of all tested fungal pathogens; F. oxysporum was found to be the most sensitive with 24.2%, 33.3%, 42.4%, and 63.6% inhibition at 25–100 μg/ml concentrations. The SEM micrograph established clear differences in the morphology of eicosane treated fungi with damaged hyphae, flaccid mycelium and collapsed spores as compared to the tubular, turgid and entire fungi in control sample. Finally, the growth curve assay depicted the right side shift in the pattern of eicosane treated fungi indicating the delay in adapting to the conditions of growth and multiplication. The findings of this study encourage further research and development towards the novel antifungal drugs that can act against major phytopathogens. • Eicosane with molecular weight of 282.5475 g/mol was identified by GC-MS analysis. • NMR analysis determined the structure of eicosane as a straight chain hydrocarbon. • Eicosane exhibited increased antifungal activity with increase in concentration. • Eicosane treated fungal cells were deformed, collapsed with shrinkage & aplanation. • Eicosane treated fungal cells failed to attain exponential growth in the analysis. [ABSTRACT FROM AUTHOR]

Summary: Thiamin (or thiamine), known as vitamin B1, represents an indispensable component of human diets, being pivotal in energy metabolism. Thiamin research depends on adequate vitamin quantification in plant tissues. A recently developed quantitative liquid chromatography–tandem mass spectrometry (LC–MS/MS) method is able to assess the level of thiamin, its phosphorylated entities and its biosynthetic intermediates in the model plant Arabidopsis thaliana, as well as in rice. However, their implementation requires expensive equipment and substantial technical expertise. Microbiological assays can be useful in deter‐mining metabolite levels in plant material and provide an affordable alternative to MS‐based analysis.Here, we evaluate, by comparison to the LC–MS/MS reference method, the potential of a carefully chosen panel of yeast assays to estimate levels of total vitamin B1, as well as its biosynthetic intermediates pyrimidine and thiazole in Arabidopsis samples.The examined panel of Saccharomyces cerevisiae mutants was, when implemented in microbiological assays, capable of correctly assigning a series of wild‐type and thiamin biofortified Arabidopsis plant samples.The assays provide a readily applicable method allowing rapid screening of vitamin B1 (and its biosynthetic intermediates) content in plant material, which is particularly useful in metabolic engineering approaches and in germplasm screening across or within species. [ABSTRACT FROM AUTHOR]

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Bloodstream infections and antimicrobial resistance are an increasing problem in low-income countries. There is a clear need for adapted diagnostic tools. To address this need, we developed a simple, universal reader prototype that detects bacterial growth in blood culture bottles. Our "turbidimeter" evaluates bacterial growth, based on the turbidity of the broth and the color change of the colorimetric CO2 indicator in commercially available blood culture bottles. A total of 60 measurements were performed using 10 relevant microbial species, spiked in horse blood, to compare the turbidimeter's performance with that of an automatic reference system. The turbidimeter was able to detect growth in all but one of the spiked blood culture bottles. In the majority (7/10) of the species tested, time-to-detection of the turbidimeter was shown to be non-inferior to the reference automated time-to-detection. This was, however, only the case when both the turbidity and color change in the colorimetric CO2-indicator were used to evaluate growth. We could not demonstrate the non-inferiority of the turbidity measurement alone. Overall, the turbidimeter performed well, but we also identified some improvements that will be implemented in the next version of the prototype. [ABSTRACT FROM AUTHOR]

The influence of preparation conditions on the size characteristics and stability of particles of aqueous dispersions of positively and negatively charged polyelectrolyte complexes based on N-succinyl chitosan and poly-N,N-diallyl-N,N-dimethylammonium chloride was studied. An increase in the concentrations of the initial polymer solutions, irrespective of the order of their mixing and the charge of the complex, makes narrower the interval of the molar ratios of the initial polyelectrolytes at which the dispersions of particles of the complexes exhibit aggregation stability. The widest interval of molar ratios at which the dispersions are stable (0.20–0.55) is observed for systems of negatively charged complexes with the initial concentration of the components of 0.05%. In the presence of 0.1 М NaCl, the initial particle radius in both types of complexes decreases to 75–80 nm. Addition of more concentrated sodium chloride solutions, especially into systems based on positively charged complexes, leads to an increase in the initial particle radius to 90–700 nm. With time, the particle size increases, and variation of the component molar ratio does not noticeably affect the particle size of the complexes. The mean particle size of polyelectrolyte complexes in the region of relative sedimentation stability of disperse systems is 75–403 nm, which opens prospects for using these particles as drug carriers for targeted delivery. [ABSTRACT FROM AUTHOR]

A method for the experimental determination of turbidity in thermoresponsive polymer solutions is presented. The method is based on measuring the intensity of light streams: weakened and backscattered from the sample, which is in the region of the volume phase transition. The turbidimeter developed by us, unlike industrial devices of this type, is equipped with a thermostat that allows to study the dependence of the solution turbidity on the temperature. The device operates automatically, the values of luminosity and temperature from digital sensors are processed by the microcontroller and transmitted via the RS-232 protocol to USB ports of a personal computer. The error of luminosity measurement does not exceed 0.1 lux, the temperature measurement accuracy is ± 0.1 °C. This article demonstrates an example of using the designed turbidimeter to study the first-order phase transition in an aqueous solution of hydroxypropylcellulose (2 wt. %) in the presence (absence) of NaCl ions. It is assumed that the sol-gel transition in the investigated solution is due to swelling of polymer coils and their subsequent aggregation. In our opinion, the displacement of the phase transition temperature is due to additional swelling of polymer coils owing to shielding of the electrostatic interaction of monomers in the presence of NaCl ions. It is shown that the intensity of backscattered light corresponds to the kinetics of the formation of the gel network, which makes it possible to establish the dimensions of formed aggregates in the network nodes. [ABSTRACT FROM AUTHOR]

The application of an adaptation strategy for probiotics, which may improve their stress tolerance, requires the identification of the growth range for each parameter tested. In this study, 4 probiotics (Lactobacillus acidophilus , Lacticaseibacillus casei , Lacticaseibacillus rhamnosus , and Lactiplantibacillus plantarum) were grown under different pH, NaCl, and sucrose concentrations at 25°C, 30°C, and 37°C. Turbidimetric growth curves were carried out and lag phase duration, maximum growth rate, and amplitude (i.e., the difference between initial and stationary phase optical density) were estimated. Moreover, cell morphology was observed, and cell length measured. The growth response, as well as the morphological changes, were quite different within the 4 species. The L. acidophilus was the most sensitive strain, whereas L. plantarum was shown to better tolerate a wide range of stressful conditions. Frequently, morphological changes occurred when the growth curve was delayed. Based on the results, ranges of environmental parameters are proposed that can be considered suboptimal for each strain, and therefore could be tested. The quantitative evaluation of the growth kinetics as well as the morphological observation of the cells can constitute useful support to the choice of the parameters to be used in an adaptation strategy, notwithstanding the need to verify the effect on viability both in model systems and in foods. [ABSTRACT FROM AUTHOR]

In analytical quality management, target setting models that are selected by the purpose together with the error models that are applied correctly have critical importance. In our study, we aimed to compare the analytical performance characteristics of routine clinical chemistry and immunoassay tests with different target-setting models proposed by various organizations. Our study was performed with internal and external quality control data obtained using Beckman Coulter AU680 for clinical chemistry analytes and Roche Cobas 8000 autoanalyzer for immunoassay analytes. The total analytical error (TAE) was calculated by the formula TAH%=1.65×(CV%)+Bias%. Measurement uncertainty (MU) has been calculated adhering to the Nordtest guideline. Results were compared with BVEFLM, CLIA, RCPA, PRDEQA%, pUEQAS%, and permissible MU (pU%) data to investigate analytical performance qualities. When we compare the results of TAE and MU, MU was found to be higher than TAE for all analytes. ALT, AST, glucose, K, and triglycerides met all target values, showing the best performance. Taken together, our results show that CLIA for total analytical error and PRDEQA% and pUEQAS% for measurement uncertainty can match better than BVEFLM, RCPA and pU%. These test results should be evaluated with measurement uncertainty to avoid misdiagnosis. Appropriate specification limits should be defined for the examination of test methods that meet the objectives for fitness for clinical purposes. [ABSTRACT FROM AUTHOR]

Around 1.5% of the total clinical biochemistry tests performed in laboratories are affected by preanalytical errors. Large, automated chemistry analysers prevent errors and interference by using control systems such as spectrophotometric measurements to evaluate serum indices, i.e. haemolysis (H), icterus (I), and lipemia/turbidity (L). However, still preanalytical errors can remain undetected. Our laboratory experienced an incident caused by laboratory-induced preanalytical errors, where approximately 100 sedimented lithium heparin samples bypassed centrifugation and entered our automated analyser. Based on index results, we investigated the possibility of using turbidimetry measurement, as a mean to prevent analysis on uncentrifuged sedimented whole blood. 14078 L-indices from 8 days in August 2019 were extracted from the middleware and used to develop and evaluate stop rules. Similarly, a one-day validation dataset was identified in December 2020 and used for an independent validation. Three different types of stop rules were evaluated: (1) A single L-index result above a cut-off; (2) A sequence of an L-index results above a cut-off; (3) A simple moving average of n results above a cut-off. A stop rule using 3 consecutive L-indices of 40–60 was found to be superior. However, practical implementation in the instrument middleware on a Roche Cobas 8000 only allowed a simple moving average of 110 (n = 5). This rule was found to be able to identify and stop sedimented whole blood analysis. Additionally, the rule has minimal impact on daily routine production in the laboratory. [ABSTRACT FROM AUTHOR]

Amaç: C-reaktif protein CRP ; inflamatuvar hastalıklarda, kardiyovasküler olaylarda, travma ve inflamasyonla ilişkili bir çok durumda belirteç olarak kullanılmaktadır. Bu çalışmada farklı cihazlar ile immunnefelometrik ve immunturbidimetrik yöntemler karşılaştırılmıştır.Gereç ve Yöntem: BN II System Siemens Diagnostics, Germany ’de rutin olarak çalışılan 150 CRP numunesi 4 düzey 10 mg/L oluşturularak çalışmaya alındı. Tüm numuneler Immage 800, Architect c16000, Beckman AU680, Cobas C501 cihazlarında çalışıldı.Bulgular: İkili grup olarak immunnefelometrik BN II System ve Immage 800 cihazlarındaki CRP sonuçları karşılaştırıldığında aralarında anlamlı fark olduğu saptanmıştır p