Citrate Buffer Solution Research Articles

A three-components-based disposable electrochemical sensor for the detection of heavy metal ions in water

The development of an efficient sensor based on a novel three-components nanocomposite is presented for the detection of heavy metal ions (Cd2+ and Pb2+) in water. For the preparation of three-components nanocomposite surface, the polydopamine reduced graphene oxide (PyDA/RGO) composite was initially prepared by a one-step polymerization of dopamine (DA) on RGO followed by surface modification of the prepared composite with cysteine (Cys). The formation of three-components nanocomposite surface (i.e., Cys/PyDA/RGO) was initially confirmed through physical characterization techniques, including X-ray diffraction and infrared spectroscopy, whereas scanning electron microscopy revealed the surface morphology after each step of sensor fabrication. The electrochemical properties of the sensing platform were evaluated through electrochemical techniques, including cyclic voltammetry and electrochemical impedance spectroscopy with an external ferri‐−/ferrocyanide redox probe. The prepared three-components nanocomposite on disposable pencil graphite electrode (Cys/PyDA/RGO/PGE) showed an improved charge transfer rate as compared to PyDA/RGO/PGE and bare PGE electrode. Targeted heavy metal ions were detected on the sensor surface using differential pulse voltammetry with greater sensitivity, showing detection limits of 0.77 and 1.13 ppb for Cd+2 and Pb+2 ions in citrate buffer solution, respectively. The sensor demonstrated comparable performance in the tap water samples.

Paintable, Fast Gelation, Highly Adhesive Hydrogels for High-fidelity Electrophysiological Monitoring Wirelessly.

High-fidelity wireless electrophysiological monitoring is essential for ambulatory healthcare applications. Soft solid-like hydrogels have received significant attention as epidermal electrodes because of their tissue-like mechanical properties and high biocompatibility. However, it is challenging to develop a hydrogel electrode that provides robust contact and high adhesiveness with glabrous skin and hairy scalp for high-fidelity, continuous electrophysiological signal detection. Here, a paintable, fast gelation, highly adhesive, and conductive hydrogel is engineered for high-fidelity wireless electrophysiological monitoring. The hydrogel, consisting of gelatin, gallic acid, sodium citrate, lithium chloride, glycerol, and Tris-HCl buffer solution exhibits a reversible thermal phase transition capability, which endows it with the attributes of on-skin applicability and fast in situ gelation with 15 s, thereby addressing the aforementioned limitations. The introduction of gallic acid enhances the adhesive properties of the hydrogel, facilitating secure electrode attachment to the skin or hairy scalp. To accentuate the potential applications in at-home electrophysiological health monitoring, the hydrogel electrodes are demonstrated for high-fidelity electrocardiogram recording for one hour during various daily activities, as well as in simultaneous electroencephalogram and electrocardiogram recording during a 30 min nap.

Inactivating Alicyclobacillus acidoterrestris spores with UVLED: Unraveling the role of turbidity, reactive oxygen species, and water dynamics

Alicyclobacillus acidoterrestris (AAT) is a spore-forming bacterium that can survive thermal pasteurization and acidic conditions. Ultraviolet light emitting diode (UVLED) has received extensive attention as a new technology to replace traditional mercury lamps for fruit juice decontamination, however, very few studies on fruit juice have been reported to investigate the sporicidal effect of UVLED on A. acidoterrestris. This research investigated for the first time the application of UVLEDs at 254 nm for the treatment of AAT in tomato juice. The optimized conditions for UVLED, achieved with the aid of Box Behnken design, were 6 cm, 12 min, and 250 mL/min. The results showed that the AAT spores in citrate buffer solution and tomato juice were inactivated by 3-log reduction with a required fluence of 53.67 mJ/cm2. Additionally, UVLED induced an exclusively cellular damage through direct absorption of UV light and direct DNA damage, and indirectly via reactive oxygen species. Besides, the deactivation of AAT spores, validated by LF-NMR analysis, indicated that the free water in AAT might be due to the rehydration of the spore core by the process of germination and then dehydration. This dehydration was further confirmed by the shrinking of spores observed through SEM and AFM imaging. These outcomes were also correlated with those of potassium ions and DPA leakage. This study emphasizes the energy-saving and resistance-reducing features of UVLED in effectively inactivating AAT.

Enhancing efficiency in ethanol production from high solid corn stover: Insights into enzymatic hydrolysis parameters and cellulase recovery

BackgroundThe simultaneous saccharification and co-fermentation (SSCF) at high solid loading is an effective approach to improve the economic feasibility of bioethanol. MethodsIn this study, the high-solid SSCF of superfine grinding corn stover was treated with cheap and readily available deionized water (DW) instead of sodium citrate buffer solution (SCBS). Additionally, the evaluation of temperature, enzyme loading, solid loading, and cellulose recovery were carried out to determine their impact on ethanol production. Significant FindingsThe results of the analysis indicated that replacing SCBS with DW had negligible effects on the SSCF of ethanol and byproducts (acetic acid and glycerol). The ethanol yield increased by 18 % at 35 °C compared to the yield at 30 °C. As enzyme loading increased, more cellulose active sites in corn stover were bound by cellulase, which increased the ethanol yield by improving the efficiency of enzymatic hydrolysis. The SSCF process didn't incorporate any buffer, resulting in an even higher ethanol titer (55.42 g/L). Furthermore, the cellulase productivity increased by 71 % after recovery, compared to the non-recovery. The results indicated that the optimized SSCF process is a potential technique for producing bioethanol on a commercial level because it improves the production efficiency while keeping costs low.

Dapagliflozin Improves Angiogenesis after Hindlimb Ischemia through the PI3K-Akt-eNOS Pathway.

Recently, the vascular protective effect of anti-diabetic agents has been receiving much attention. Sodium glucose cotransporter 2 (SGLT2) inhibitors had demonstrated reductions in cardiovascular (CV) events. However, the therapeutic effect of dapagliflozin on angiogenesis in peripheral arterial disease was unclear. This study aimed to explore the effect and mechanism of dapagliflozin on angiogenesis after hindlimb ischemia. We first evaluated the effect of dapagliflozin on post-ischemic angiogenesis in the hindlimbs of rats. Laser doppler imaging was used to detect the hindlimb blood perfusion. In addition, we used immunohistochemistry to detect the density of new capillaries after ischemia. The relevant signaling pathways of dapagliflozin affecting post-ischemic angiogenesis were screened through phosphoproteomic detection, and then the mechanism of dapagliflozin affecting post-ischemic angiogenesis was verified at the level of human umbilical vein endothelial cells (HUVECs). After subjection to excision of the left femoral artery, all rats were randomly distributed into two groups: the dapagliflozin group (left femoral artery resection, receiving intragastric feeding with dapagliflozin (1 mg/kg/d), for 21 consecutive days) and the model group, that is, the positive control group (left femoral artery resection, receiving intragastric feeding with citric acid-sodium citrate buffer solution (1 mg/kg/d), for 21 consecutive days). In addition, the control group, that is the negative control group (without left femoral artery resection, receiving intragastric feeding with citric acid-sodium citrate buffer solution (1 mg/kg/d), for 21 consecutive days) was added. At day 21 post-surgery, the dapagliflozin-treatment group had the greatest blood perfusion, accompanied by elevated capillary density. The results showed that dapagliflozin could promote angiogenesis after hindlimb ischemia. Then, the ischemic hindlimb adductor-muscle tissue samples from three rats of model group and dapagliflozin group were taken for phosphoproteomic testing. The results showed that the PI3K-Akt-eNOS signaling pathway was closely related to the effect of dapagliflozin on post-ischemic angiogenesis. Our study intended to verify this mechanism from the perspective of endothelial cells. In vitro, dapagliflozin enhanced the tube formation, migration, and proliferation of HUVECs under ischemic and hypoxic conditions. Additionally, the dapagliflozin administration upregulated the expression of angiogenic factors phosphorylated Akt (p-Akt) and phosphorylated endothelial nitric oxide synthase (p-eNOS), as well as vascular endothelial growth factor A (VEGFA), both in vivo and in vitro. These benefits could be blocked by either phosphoinositide 3-kinase (PI3K) or eNOS inhibitor. dapagliflozin could promote angiogenesis after ischemia. This effect might be achieved by promoting the activation of the PI3K-Akt-eNOS signaling pathway. This study provided a new perspective, new ideas, and a theoretical basis for the treatment of peripheral arterial disease.

Acid attack on hydrated cement: effect of organic acids on the degradation process

Owing to their ability to form buffer solutions, the attack of organic acids on concrete structural components can be highly aggressive. This work considers the changes in microstructure, chemical and phase composition in hardened Portland cement paste (hcp) exposed to acetic acid/sodium acetate or citric acid/sodium citrate buffer solutions. The degradation products were investigated using 29Si and 27Al NMR spectroscopy with XRD and ICP-OES. Exposure to acetic acid/sodium acetate at pH 3.9 ≤ pH ≤ 5.5 decalcifies hcp to produce aluminosilica gels (0.1 ≤ Al/Si ≤ 0.3) with Si predominately in Q3/Q4 sites and NBO values (non-bridging oxygen per Si atom) 0.6 ≤ NBO ≤ 0.9. Cross-linking processes causing the formation of the gel from C–A–S–H dreierketten incorporate Al, originally in crystalline phases and C–A–S–H phases. Degradation by citric acid/sodium citrate is governed by the precipitation of expansive calcium citrate which continuously removes degraded surface material. Pore-blocking at the degradation front inhibits acid transport deeper into the material. A new mathematical expression is presented which enables the calculation of NBO for aluminosilica gels of known Al/Si ratio from 29Si NMR spectra despite overlapping signals. The expression was verified by a stochastic computer model based on a Si quartz lattice with substituted Al and vacancies. The model simulated the measured 29Si NMR spectra of aluminosilica gels.

PECULIARITIES OF RESPIRATORY CELLULAR IMPLICATIONS IN STREPTOZOTOCIN-INDUCED DIABETES: A FOCUS ON TYPE I ALVEOLOCYTES

Introduction. The escalating global prevalence of diabetes mellitus has ignited concerns, given its multifaceted repercussions that extend beyond conventional metabolic considerations. Recent scientific inquiries have firmly established a profound association between diabetes mellitus and abnormalities within the respiratory system, unveiling a nuanced interplay that transcends mere glycemic control. This study delves into the intricate and far-reaching influence of diabetes on the respiratory system, recognizing it as a vulnerable target organ susceptible to systemic repercussions. Compelling epidemiological evidence underscores a heightened prevalence of respiratory complications among individuals grappling with diabetes. This observation prompts a meticulous exploration of the pathophysiological underpinnings of this intricate relationship, spanning from molecular intricacies to clinical manifestations.
 The aim was to deepen our understanding of the impact of diabetes mellitus on the respiratory system by investigating the pathological alterations in type I alveolocytes within an experimental model of diabetes mellitus.
 Methods. In this experimental model we used 88 male Wistar rats (170-210 g). The rats were divided into three groups: Group 1 (n=10) consisted of intact rats; Group 2 (n=40) served as the control group, and Group 3 (n=38) constituted the experimental group where diabetes was induced by intraperitoneal administration of streptozotocin (Sigma, USA) diluted in 0.1 M citrate buffer with pH 4.5 at a dosage of 60 mg/kg of body weight. The control group received an equivalent volume of 0.1 M citrate buffer solution with a pH of 4.5 via intraperitoneal injection. All procedures were performed under sodium thiopental anesthesia at a dose of 60 mg/kg of body weight. Tissue samples were collected at intervals of 14, 28, 42, and 70 days post streptozotocin injection.
 For electron microscopy analysis, fragments of lung tissue were immersed in a 2.5% glutaraldehyde solution for fixation, followed by fixation in a 1% osmium tetroxide solution. After dehydration, the specimens were embedded in Epon Araldite. Sections, obtained through a "Tesla VS-490" ultramicrotome, underwent examination using a "PEM-125K" electron microscope.
 Results. Throughout the experiment, discernible changes in type I alveolocytes were observed. At 14 days, nuclei exhibited rounding or oval shape with uniform chromatin distribution. Mitochondria displayed small size, and the Golgi apparatus (GA) and granulated endoplasmic reticulum (GER) showed no significant alterations. By 28 days, nuclei adopted an oval shape, chromatin localized peripherally, and mitochondria exhibited diverse morphologies. Increased micropinocytotic vesicles indicated heightened cellular activity. At 42 days, hyperhydration became pronounced, nuclei displayed lower electron density, and cellular components showed advanced changes. By 70 days, dystrophic-destructive changes included low electron density nuclei, disorganized mitochondria, and fragmented GA and GER.
 Conclusion. This comprehensive ultrastructural analysis unveils the progressive impact of diabetes on type I alveolocytes, elucidating unique facets of pulmonary alterations over time. This study contributes to a growing body of knowledge, shedding light on the dynamic nature of pulmonary changes in diabetes mellitus, ultimately urging further exploration for a holistic understanding of its implications on respiratory health.

Investigating freezing-induced acidity changes in citrate buffers

Citrate buffers are commonly utilized in the field of biomolecule stabilization. We investigate their applicability in the frozen state within a range of initial pHs (2.5 to 8.0) and concentrations (0.02 to 0.60 M). Citrate buffer solutions subjected to various cooling and heating temperatures are examined in terms of the freezing-induced acidity changes, revealing that citrate buffers acidify upon cooling. The acidity is assessed with sulfonephthalein molecular probes frozen in the samples. Optical cryomicroscopy combined with differential scanning calorimetry was employed to investigate the causes of the observed acidity changes. The buffers partly crystallize and partly vitrify in the ice matrix; these processes influence the resulting pH and allow designing the optimal storage temperatures in the frozen state. The freezing-induced acidification apparently depends on the buffer concentration; at each pH, we suggest pertinent concentration, at which freezing causes minimal acidification.

Effect of dual-frequency thermosonication, food matrix, and germinants on Alicyclobacillus acidoterrestris spore germination

The off-odors associated with spoilage of acidic beverages are linked to the germination and growth of Alicyclobacillus acidoterrestris (AAT) spores. As a consequence, we determined the influence of nutrients, non-nutrient germinants, dual-frequency thermosonication (DFTS), and food matrix on spore germination. AAT spores in orange juice (OJ), supplemented by L-alanine (L-ala), had the highest germination rate and lowest DPA content at 10 h of incubation. The formation of microscopic pores in cell membranes during DFTS caused irreversible damage in AAT spores in citrate buffer solution (CBS); however, it stimulated AAT spore germination in CBS containing L-ala. Hence, the germination potential was established in the order: L-ala > Calcium dipicolinate > asparagine, glucose, fructose, and potassium ion mixture (AGFK) > L-valine. The conductivity analysis indicated that membrane damage could be a key factor contributing to the artificial germination in CBS. AFM images revealed that after 2 h of adding L-ala, the protein content increased with increased germinated cells. TEM showed that membrane poration and coat detachment were the main pre-germination morphological changes detected after DFTS treatment. This study provides evidence that germination stimulated with DFTS might be an effective strategy for reducing A. acidoterrestris spores in fruit juices.

Rapid Elution of 226Th from a Two-Column 230U/226Th Generator with Diluted and Buffer Solutions.

A radionuclide generator of the short-lived alpha emitter 226Th was proposed. An original scheme consisting of two in-series chromatographic columns was developed for rapidly producing a neutral citric-buffered eluate of high purity 226Th. The first column filled with TEVA resin retained the parent 230U, while 226Th was eluted with 7 M HCl solution to be immediately adsorbed on the second column containing DGA resin or UTEVA resin. Having substituted the strongly acidic medium of second column with neutral salt solution, 226Th was desorbed with diluted citric buffer solution. One cycle of generator milking took 5-7 min and produced >90% of 226Th in 1.5 mL of eluate (pH 4.5-5.0) appropriate for direct use in radiopharmaceutical synthesis. The 230U impurity in 226Th eluate was less than 0.01%. The proposed two-column 230U/226Th generator was tested over 2 months including a second loading of 230U additionally accumulated from 230Pa.

Optimization of Tacrolimus Loaded Reconstituted Nanoparticles by QbD Method

The aim of the present study is to implement QbD approach for development and optimization of Tacrolimus Loaded Reconstituted Nanoparticles. Tacrolimus-loaded nanoparticles were prepared by using Kollisolve PEG 300, Kolliphor ELP, Citrate buffer solution and Tween 80. The aqueous medium was added drop by drop into the organic phase at continuous stirring on a magnetic stirrer for half an hour. The solution then homogenized at high pressure that reduced particle size. Drying was done by using Low Endotoxin Lactose Monohydrate as a carrier. The final reconstituted powder stored in a closed container and assessed for zeta potential, drug loading, FT-IR Studies, Particle Size Analysis, SEM, X-Ray Diffraction, DSC etc. Optimization was performed by using Design Expert 8 software, 3 Level Factorial design was selected from Response Surface Design. The drug was found to be 98.65% w/w by assay. The particle size was found to be in the range of 263nm - 500nm. Tacrolimus powder shows O-H stretching vibration at 3374.91cm−1, C = O stretching vibrations at 1733.38 cm−1, and C = C stretching vibration at 1631.55 cm−1, C–O (ester) stretching vibration at 1248.11 cm−1. Tacrolimus nanoparticles were optimized by QbD method, Methanol: Phosphate Buffer (80:20) solvent phase was used having pH 6. The maximum wavelength of Tacrolimus was found to be 293nm. The desirability value of that optimized method was found to be 1. Tacrolimus Loaded Reconstituted Nanoparticles leads to enhanced solubility and we can conclude that an increase in pH was responsible for increment in absorbance and thus showed the direct relationship between them.

Subtle Intricacies Identified during Streptozotocin-Induced Diabetes in Wistar Rats

Abstract: Aim: This study aimed to establish the dose of streptozotocin required to induce Type -1 diabetes in Wistar rats. Background: Streptozotocin is currently employed worldwide to induce insulin-dependent diabetes mellitus also known as Type 1 diabetes mellitus in experimental animals. Though many reports on the use of streptozotocin induction of diabetes are reported in the literature, they were not reproducible. Moreover, there was no mention of the mortality associated with the same as well as the conditions followed during the study. Materials and Methods: In the present study, the dose, route, and solvent used for streptozotocin were investigated. Various doses of streptozotocin 55, 50, 40, and 35mg/kg dissolved in either freshly prepared cold 10mM sodium citrate buffer (pH 4.5) or normal saline solution was administered intraperitoneally as well as intravenously. For intraperitoneal administration, the dose-volume was 10mL/kg whereas for intravenous administration the dose-volume was 2mL/Kg. Different routes were employed to ascertain the cause of mortality for which an autopsy was performed. Besides mortality rate was also determined. Results and Discussion: The findings of the study revealed that a 35-40mg/kg dose of streptozotocin showed less percentage mortality and successful induction of diabetes. Conclusion: Mortality (10-20%) was observed at a dose of 35-40mg/kg streptozotocin. Therefore, streptozotocin (35-40mg/kg) was confirmed to be safe and effective for the induction of diabetes in Wistar rats. This paper highlights subtle intricacies observed during induction of diabetes in Wistar rats using streptozotocin Keywords: Male Wistar rats, Streptozotocin, Type-1 diabetes, 5% dextrose, Mortality, Normal saline solution.

Pharmacological Studies on the Antidiabetic, Antioxidant, and Antimicrobial Efficacies of Commiphora myrrha Resin in Streptozotocin-Induced Diabetes in Rats: A Preclinical Study.

The aqueous extracts of MAE were phytochemically analyzed, and the results revealed the presence of high concentrations of tannins, sterols, and isoprenoids (terpenoids), while steroids and flavonoids were found in moderate concentrations. The plant extract showed promising inhibition of the growth of gram-positive and gram-negative pathogens. It also showed that MAE has potential antihyperglycemic and antioxidant activities. Microscopic examination of the pancreas showed degenerative changes and atrophy associated with dilatation of the exocrine ducts in the STZ-induced diabetic rats, while the treatment revealed that the Langerhans islets were close to normal without any histopathological alteration. The present results suggested that an aqueous extract of MAE could be considered an efficient antidiabetic, antioxidant, and antimicrobial treatment in the future.

FEATURES OF CYTOKINE PROFILE OF BLOOD IN RATS WITH STREPTOZOTOCIN-INDUCED DIABETES

In the pathogenesis of many diseases, including diabetes mellitus, cytokines play a crucial role. It is known that cytokines are the regulators of intercellular and intersystem interactions, ensuring the consistency of the actions of the endocrine, immune, and nervous systems under standard conditions and in response to pathogenetic factors, and are involved in the development of autoimmune processes. It was established that proinflammatory cytokines, namely tumor necrosis factor-alpha, interleukin-1β, and interleukin-6 play a significant role in the loss of insulin-producing function by beta cells of the islets of Langerhans, as well as are implicated in the formation of insulin resistance in peripheral tissues.
 The aim is to study the dynamics of the content of tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6) in the blood serum of rats with streptozotocin-induced diabetes.
 Materials and methods The experiments were performed on 88 white male Wistar rats weighing 170–210 g, which were kept on a standard diet with free access to water. Animals were divided into three groups: 1 – intact (n=10); 2 – control (n=40); 3 – experimental (n=38) with a model of diabetes mellitus, which was reproduced by intraperitoneal injection of streptozotocin by "Sigma" company (USA), diluted in 0.1 M citrate buffer with a pH of 4.5, at a rate of 60 mg/kg body weight. The control group of animals received an intraperitoneal injection with an equivalent dose of 0.1 M citrate buffer solution with a pH of 4.5. Serum levels of TNF-α, IL-1β, and IL-6 were determined by rat enzyme-linked immunosorbent assay Rat ELISA Kits (Elabscience, USA) according to the manufacturer's instructions 14, 28, 42 and 70 days after streptozotocin injection. To assess the reliability of data changes in dynamics (14, 28, 42, 70 days) within each of the comparison groups, a non-parametric method was used (for three or more comparison groups) - Friedman's analysis of variance and Kendall's coefficient of concordance (Friedman ANOVA and Kendall's W).
 Results Conducted biochemical studies of blood serum showed that in animals with streptozotocin-induced diabetes, there was an increase in the content of proinflammatory cytokines at all stages of the experiment. In particular, TNF-α increased by 11.8% in 14 days, 34.4% in 28 days, 59.1% in 42 days and 80.1% in 70 days after the start of the experiment. An increase in the level of IL-1β was observed in the blood serum at the same time. In 14 days, the content of this cytokine increased by 22.5%, in 28 days increased by 40.2%, in 42 days increased by 72.8%, in 70 days increased by 107.2%. Along with this, we also observed an increase in the activity of IL-6 levels. In 14 days, in the blood serum, the IL-6 level was increased by 17.5%, in 28 days by 33.2%, in 42 days by 60.6% and after 70 days by 94.9% compared to the control group of animals. The analysis of the dynamics of pro-inflammatory cytokines TNF-α, IL-1β, and IL-6 in blood serum under conditions of experimental diabetes indicates their unidirectional changes.
 Conclusions The conducted studies showed that pro-inflammatory cytokines play a leading role in the pathogenesis of diabetes mellitus: TNF-α, IL-1β, and IL-6, which is indicated by a significant increase in the levels of such cytokines in blood serum at all stages of the experiment. The most pronounced changes in pro-inflammatory cytokines levels are observed at 70-day.

Ultrastructural organization of the respiratory part of the lungs in streptozotocin-induced diabetes

Background. Diabetes mellitus is a metabolic disease characterized by persistent hyperglycemia, the prevalence and incidence of which have dramatically increased worldwide. Our research aimed to study the dynamics of changes in the components of the respiratory part of the lungs in streptozotocin-induced diabetes. Materials and methods. The experiments were performed on 88 white male Wistar rats weighing 170-210 g. The animals were divided into three groups: 1 - intact (n=10); 2 - control (n=40); 3 - experimental (n=38) with a model of diabetes mellitus, which was reproduced by intraperitoneal injection of streptozotocin company "Sigma" (USA), diluted in 0.1 M citrate buffer with pH 4.5, at a rate of 60 mg/kg body weight. The control group of animals received an intraperitoneal injection with an equivalent dose of 0.1 M citrate buffer solution with a pH of 4.5. Pulmonary tissue collection for electron microscopic examination was performed under thiopental anesthesia 14, 28, 42, and 70 days after streptozotocin injection. Pieces of lung tissue were fixed in 2.5% glutaraldehyde solution, followed by fixation in 1% osmium tetroxide solution. After dehydration, the material was poured into epon-araldite. Sections obtained on an ultramicrotome "Tesla BS-490" were studied in an electron microscope «PEM-125K». All studies were performed under sodium thiopental anesthesia at the rate of 60 mg/kg of body weight. Results. Our research showed that 14 days after the modeling of streptozotocin-induced diabetes, mainly reactive changes were observed in the components of the respiratory part of the lungs. With an increase in the duration of the study (28-70 days), changes of a dystrophic-destructive nature were noted in alveolocytes of types I and II, and endotheliocytes of hemocapillaries. At the same time, cells with increased functional activity were determined in the components of the respiratory part of the lungs. Conclusion. Streptozotocin-induced diabetes leads to violations of the ultrastructural organization of components of the respiratory part of the lungs. The nature and severity of structural changes in type I, II alveolocytes, and endotheliocytes of hemocapillaries depend on the duration of diabetes.

A simple, ultrasensitive and cost-effective electrochemical sensor for the determination of ciprofloxacin in various types of samples

In this study, a simple, ultrasensitive, inexpensive, and environmentally friendly sensor was developed for the electrochemical determination of ciprofloxacin (CPRO) using a choline chloride-modified carbon paste electrode (ChCl/CPE). The electrochemical properties of ChCl/CPE were examined by square wave voltammetry (SWV). Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), ultraviolet-visible (UV–Vis) spectroscopy, and Fourier transform infrared (FT-IR) spectrometry were used for electrochemical and morphological characterizations. The sensor exhibits excellent conductivity and superior electrocatalytic activity, within the linear range of 0.005–200 μM, for the detection of CPRO in citrate buffer solution (CBS) at pH 5, with detection and quantification limits of 0.36 nM and 1.2 nM. The electroactive surface area of ChCl/CPE was calculated to be 0.123 cm3, which is four times higher than that of the bare CPE (0.037 cm2). The ChCl/CPE is not only simple, inexpensive and time-saving, but also has the lowest detection limit and widest linear range compared to the recently reported sensors for the determination of CPRO. The developed sensor also showed excellent reproducibility, repeatability, long-term stability, and exceptional selectivity against potentially interfering organic, inorganic, and antibiotic species. In addition, ChCl/CPE was successfully applied for the determination of ciprofloxacin in eye drops, river water, and egg samples with very good recoveries of 97–102% and relative standard deviations (RSD) of 0.27–3.85%. Therefore, the proposed electrochemical sensor is a potential candidate for the determination of ciprofloxacin in various matrices.

Simultaneous determination of five triarylmethane colorants in syrup by applying multivariate curve resolution to second-derivative visible absorption spectra.

A method for the simultaneous determination of five triarylmethane colorants (brilliant blue FCF, patent blue V, patent blue VF, fast green FCF, and green S) in syrup samples was proposed by applying multivariate curve resolution to second-derivative visible absorption spectra in citrate and carbonate buffer solutions. Even for heavily overlapping spectra, adopting second-derivative spectra and multiway analysis in citrate and carbonate buffer solutions enhanced specificity for the analytes and achieved prediction performance with a coefficient of determination (R2) > 0.90, root mean square error of prediction (RMSEP) < 0.20mg/L, and limit of detection (LOD) < 0.50mg/L for all five analytes. The basis set expansion method succeeded in a reasonable estimation of the second-derivative spectra with the interferant. For commercial syrup samples, the present method predicted results without significant differences compared to the results measured using liquid chromatography-mass spectrometry. The proposed method provides a rapid alternative to liquid chromatography techniques for the quantification of multiple colorants in food samples.

Dynamics of endogenous intoxication in experimental diabetes mellitus

Background. Nowadays, diabetes mellitus is defined as one of the global medical and social problems and shows a growing tendency. The purpose of the study was to analyze the dynamics of endogenous intoxication in experimental diabetes mellitus. Materials and methods. The experiments were performed on 88 white male Wistar rats weighing 170-210 g. Animals were divided into three groups: 1 - intact; 2 - control; 3 - experimental with a model of diabetes mellitus, which was reproduced by intraperitoneal injection of streptozotocin by “Sigma" company (USA), diluted in 0.1 M citrate buffer with a pH of 4.5, at a rate of 60 mg/kg body weight. The control group of animals received an intraperitoneal injection with an equivalent dose of 0.1 M citrate buffer solution with a pH of 4.5.&#x0D; All studies were performed under thiopental-sodium anesthesia at a rate of 60 mg/kg body weight. To determine endogenous intoxication, blood sampling of middle mass molecules (MMM) was performed 14, 28, 42 and 70 days after the streptozotocin injection. Detection of MMM fractions was performed by spectrophotometer «SF46» at the wavelength of 254 nm (MMM254) and 280 nm (MMM280). The STATISTICA 10 program was used for statistical processing of the obtained results. Results. The conducted biochemical studies of blood serum showed that in animals with streptozotocin-induced diabetes mellitus there was an increase in the content of both MMM fractions compared to the similar indicators of the control group of animals at all stages of the experiment: in the 14 days increased by 32,9% - MMM254, by 12.7%- MMM280, in the 28 days increased by 44,3 % MMM254, by 34,0 % MMM 280, in the 42 days increased by 62,8 % MMM254, by 64,8 % MMM280, in 70 days increased by 76,1 % MMM254, by 81,1% MMM280. Conclusions. Streptozotocin-induced diabetes mellitus is accompanied by an increase in the level of endogenous intoxication which is manifested by an increase of both MMM fractions content in serum.&#x0D; The severity of endogenous intoxication depends on the duration of the endogenous factor.

Effect of Erosive Agents on Surface Characteristics of Nano-Fluorapatite Ceramic: An In-Vitro Study.

Erosive beverages cause dissolution of natural teeth and intra-oral restorations, resulting in surface characteristic changes, particularly roughness and degradation. The purpose of this study was to evaluate the surface roughness and topography of a dental ceramic following immersion in locally available erosive solutions. A total of 160 disc specimens of a nano-fluorapatite type ceramic (12 mm diameter and 2 mm thickness) were fabricated and equally distributed into two groups (n = 80) and then evenly distributed among the following five testing groups (n = 16): lemon juice, citrate buffer solution, 4% acetic acid, soft cola drink, and distilled water which served as a control. The surface roughness (Ra) and topography were evaluated using a profilometer and scanning electron microscope at baseline, 24 h, 96 h, and 168 h respectively. Data were analyzed using ANOVA and Tukey’s multiple comparisons (p ≤ 0.05). Surface changes were observed upon exposure to all acidic beverages except distilled water. Amongst all immersion media, 4% acetic acid produced the most severe surface roughness across all time periods (i.e., baseline, 24 h, 96 h, and 168 h). A statistically significant difference in the surface roughness values between all immersion media and across all four time intervals was observed. Erosive agents had a negative effect on the surface roughness and topography of the tested ceramic. The surface roughness increased with increased storage time intervals.

Pasting Properties of Mocaf (Modified Cassava Flour) Using Rapid Visco Analyzer With Variations of pH Solution

Starch is a glucose polysaccharide which includes amylose and amylopectin. Natural starch in its utilization has several weaknesses so that modified starch begins to develop, one of which is MOCAF. MOCAF is a modified cassava flour by fermentation using lactic acid bacteria (BAL). The weakness of natural starch is become thicky when the food processing at high temperature and acidic conditions. MOCAF is expected to be able to provide solutions for food processing at high temperatures and acidic conditions. This research was conducted to determine the gelatinization profile of MOCAF during processing at several pH levels. Physical properties of the MOCAF firstly were analyzed including water, starch, amylose, and amylopectin content. After that, the MOCAF gelatinization profile was measured using a Rapid Visco Analyzer (RVA), with observation parameters namely peak viscosity (PV), minimum viscosity (MV), breakdown (BD), final viscosity (FV), setback (SB), pasting temperature (PT), and peak time (Ptime). The results showed that the acidic conditions affected the gelatinization profile of the starch. In the sample which was mixed with citrate buffer solution pH 3 showed the highest peak viscosity (4206.4 cP) and breakdown (3047.6 cP), while the lowest minimum viscosity (1158.6 cP), final viscosity (1604.0 cP), setback (445.2 cP), pasting temperature (74.28°C), and peak time (4.31 minutes). Thus, the low-pH processed MOCAF has the lowest viscosity stability and retrogradability.