Organic Sensitizers Research Articles

Organic sensitizer with azine π-conjugated architecture as co-sensitizer and polymer-based electrolyte for efficient dye-sensitized solar cell

The donor-π-acceptor architecture of a novel organic sensitizer (NHC) is synthesized and used in dye-sensitized solar cells (DSSCs). An azine-spacer (=N-N=) is employed to connect the 3-nitrobenzene anchor unit with the carbazole donor in the sensitizer. Photophysical, electrochemical, and photovoltaic performances of the synthesized dye are studied in depth. Further, polymer-based electrolytes were prepared by doping 1-n-hexyl-3-methylimidazolium iodide (HMIm+I−) to the polyvinylidene fluoride electrolyte solution and studied their conductivity and dielectric properties. DSSC fabricated with NHC dye and HMIm+I−-20% electrolyte displayed an efficiency of 1.24%. In addition, NHC co-sensitization with bis(isothiocyanato)(2,2′-bipyridyl-4,4′-dicarboxylato)(4,4′-dinonyl-2,2′-bipyridyl)ruthenium(II) (Z907) is investigated. As a result, the co-sensitized device exhibit greater photovoltaic performance, with an efficiency of 4.76% compared to the cell with Z907 (4.17%) alone, owing to higher short-circuit current density in conjunction with higher open-circuit voltages.

Synthesis of innovative triphenylamine-functionalized organic photosensitizers outperformed the benchmark dye N719 for high-efficiency dye-sensitized solar cells

Herein, we present a thorough photovoltaic investigation of four triphenylamine organic sensitizers with D–π–A configurations and compare their photovoltaic performances to the conventional ruthenium-based sensitizer N719. SFA-5–8 are synthesized and utilized as sensitizers for dye-sensitized solar cell (DSSC) applications. The effects of the donor unit (triphenylamine), π-conjugation bridge (thiophene ring), and various acceptors (phenylacetonitrile and 2-cyanoacetamide derivatives) were investigated. Moreover, this was asserted by profound calculations of HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) energy levels, the molecular electrostatic potential (MEP), and natural bond orbital (NBO) that had been studied for the TPA-sensitizers. Theoretical density functional theory (DFT) was performed to study the distribution of electron density between donor and acceptor moieties. The sensitization by the absorption of sensitizers SFA-5–8 leads to an obvious enhancement in the visible light absorption (300–750 nm) as well as a higher photovoltaic efficiency in the range of (5.53–7.56%). Under optimized conditions, SFA-7 showed outstanding sensitization of nanocrystalline TiO2, resulting in enhancing the visible light absorption and upgrading the power conversion efficiency (PCE) to approximately 7.56% over that reported for the N719 (7.29%). Remarkably, SFA-7 outperformed N719 by 4% in the total conversion efficiency. Significantly, the superior performance of SFA-7 could be mainly ascribed to the higher short-circuit photocurrents (Jsc) in parallel with larger open-circuit voltages (Voc) and more importantly, the presence of different anchoring moieties that could enhance the ability to fill the gaps on the surface of the TiO2 semiconductor. That could be largely reflected in the overall enhancement in the device efficiency. Moreover, the theoretical electronic and photovoltaic properties of all studied sensitizers have been compared with experimental results. All the 2-cyanoacrylamide derivative sensitizers demonstrated robust photovoltaic performance.

Rational design of ZL003-based organic dyes for highly efficient dye-sensitized solar cells: Influence of alkynyl group and π-spacers on photovoltaic performance

Dye-sensitized solar cells (DSSCs) have displayed huge potential in inexpensive, efficient, and clean solar energy-technology. To achieve highly efficient DSSCs, a series of D-π-A organic dyes were designed and their optoelectrical properties were calculated by density functional theory (DFT) and time-dependent density functional theory (TD-DFT). Compared with ZL003, ZS1 designed by introducing the triple bond between donor and π bridge, has higher conjugation, narrower HOMO-LUMO bandgap, and extended absorption spectra. Then five new organic dyes were designed by substituting benzothiadiazole part of ZS1 with five electron-deficient heterocycles. The designed dyes have more conjugated structure, which leads to stronger light harvesting ability with the absorption spectra expanding to the near infrared region, the maximum absorption wavelength red shifting 78 nm∼448 nm and light harvesting efficiency (LHE) curve broadening obviously. The intermolecular electron transfer (IET) rate of the design dye is much faster than that of ZL003, over 85.3% of electrons in the design dye have been injected into TiO2 within 200 fs. Especially, the power conversion efficiency (PCE) of BBTD, BTTD and BZOD is more than 25.7%, mainly reflected in the obvious jump of the theoretical short current density (Jscpred.) by more than 68%. Therefore, the design dyes have a good application prospect. We believe that this work could provide theoretical guidance for the design of potential organic sensitizers in highly efficient DSSCs.

Accumulation of microplastics in fish guts and gills from a large natural lake: Selective or non-selective?

In recent years, microplastics (MPs) have become emerging contaminant causing widespread concern about their ecotoxicological effects. However, little is known regarding the accumulation of MPs in different tissues of fishes, especially for freshwater fishes in natural environments. In this study, MPs in guts and gills of 11 fish species from Lake Chao, China were examined to explore the accumulation differences and foraging preferences of MPs. In general, MPs in fish guts varied from 2.85 to 8.38 items/individual, while ranged from 3.06 to 8.90 items/individual in fish gills. In terms of characteristic composition (shape, color, size, and polymer type), our results demonstrate higher occurrence of fibrous, black, small sized (<1 mm), and polypropylene MPs. Meanwhile, MPs concentrations in fish guts differed significantly among various feeding groups, with none significant difference detected in fish gills. In addition, fish guts exhibit more distinct foraging preferences for specific featured MPs in contrast with fish gills. These results indicate selective MPs accumulation in fish guts whereas random MPs accumulation in fish gills. Fish gills, adhering MPs by non-selective water exchange, may be more related to the real-time MPs abundance in water. To some extent, fish gills may be employed as important instruments to reflect MPs contamination in aquatic environments. Influenced by diverse feeding behaviors such as visual cues and sensory systems, MPs accumulation in fish guts reflect intrinsic differences, thus making fish guts sensitive organ in monitoring MPs’ ecological risk for their health.

A locust bean and pectin polymer blend integrated with thio-bridged pyridinyl additive as a novel cobalt and copper gel electrolyte system for dye-sensitized solar cells

An intensive correlation has been attempted on 2-(pyridin-2-yl)-1-(4-(trifluoromethyl)phenyl)-1H-benzo[d]imidazole ligand-coordinated cobalt and copper metal complex electrolytes (Co2+/3+[ptpbi]3 and Cu1+/2+[ptpbi]2) with blend biopolymer electrolyte based on Locust Bean Gum and Pectin (LP) as a host matrix to enhance the performance of organic DPTCY sensitizer (2D-π-D′-A-π-A). Comparatively, the ligand coupled bulky CF3 acceptor on the para position of benzyl moiety-substituted 2-(pyridin-2-yl)-benzimidazole (on the N–H position) [ptpbi]-coordinated copper metal complex shows a higher redox potential (0.62 V vs NHE) compare to Co2+/3+ redox system. The photovoltaic performance of thio-bridged pyridinyl based organic compounds (MPP and DSP) with/without highly electron-donating substituents (methyl group) as an additive in QSSE host for dye-sensitized solar cell applications has been employed. A thorough investigation has been made for blending polysaccharide polymer-based electrolytes E1 to E4 through DSC, FTIR, UV–Vis spectroscopic techniques. The analysis of assembled device as [TiO2/DPTCY Dye/Mn+/m + redox/additive/LP blend biopolymer/Pt] has achieved a maximum PCE of 5.97% under 1 sun (100 mW cm−2) condition with 1.5AM. These results signify a record for copper complex with methyl-substituted thio-bridged pyridinyl (MPP) with higher efficiency. These devices had shown a higher chemical capacitance (6.06 × 10−6 F), recombination resistance (25.5 Ω), charge transfer resistance (5.67 Ω), ionic conductivity (1.568 (S cm−1) × 10−3), electron lifetime (48.97 ms), diffusion coefficient (2.63 × 10−7 cm−2 s), dielectric constant (2.76 × 102) and dielectric loss (4.41 × 103) compared with other substitution-based additives. These additives have trapped the diffusion of Cu2+ and Co3+ ion species has resulted in the constraint resistance and enhancement of the catalytic effect of the counter electrode. The higher charge relaxation time and a negative shift in the Quasi-Fermi level of TiO2 arise by correlating photocurrent and photovoltage in suppression of recombination reaction.

Enhancement of power conversion efficiency of dye-sensitized solar cell via symmetrical Bi-anchoring organic molecules as co-sensitizer

A strategy has carried to improvise the photovoltaic performance of DSSCs using auxiliary compounds as co-sensitizer along with organic sensitizer. Herein, bi-anchoring metal-free aromatic organic molecules (A-π-A) based co-sensitizer was utilized with organic sensitizer (DTTCY) and a Co 2+/3+ [bnbip] redox couple incorporated PEG-HEC quasi-solid-state electrolyte for an efficient DSSCs. Interestingly, ACY organic co-sensitized device (typically TiO 2 /ACY/DTTCY/Co 2+/3+ [bnbip]/PEG-HEC/Pt) has achieved a maximum power conversion efficiency of 8.3% under AM 1.5 G illumination (100 mW cm −2 ). At the same instance, NCY and PCY co-sensitized devices achieved comparably lower PCE of 7.44% and 6.99% respectively. These results prove that longer π-conjugation and bi-anchoring group of ACY molecules has induced electron injection process on TiO 2 surface. The influences of co-sensitizer are strongly covered the naked spectrum in the UV region and fill the vacant area in TiO 2 that induces a change in Quasi Fermi level of and decreases recombination flanked by photo-anode and oxidized cobalt species. The PCE results of ACY sensitized device are sustained by some electrochemical factors such as Bulk Resistance (R s = 17.23 Ω), Recombination Resistance (R Rec = 18.84 Ω), Charge Transfer Resistance (R CT = 1.136 Ω), Chemical capacitance (C μ = 13.66 μF), Ionic Conductivity (σ = 2.31 E −03 S cm −1 ), electron lifetime (τ n = 52.85 μs), electron transport time (τ d = 3.29.\μs) and collection efficiency (η COL = 93.97 %), rate of reaction constant (K eff = 18.92 s −1 ), Electron Density (n s = 1.21 E +17 cm −3 ), Dielectric constant (D eff = 0.011 mm 2 s -1 ), Dielectric Length (L n = 0.776 mm). The opportunity of trapping the co-sensitizer system functionalizes the anode surface supposed to avoid back electron transfer and dye degradation. The motive of the study is to enhance the photo-ability of metal-free DTTCY sensitizer along with metal-free co-sensitizer and metal-free additives integrated into the blend polymer electrolyte. • Design and synthesis of (A-π-A) based co-sensitizer for DSSCs application. • PEG-HEC polymer with Cobalt redox couple used as an effective QSS electrolyte. • ACY organic co-sensitized device has achieved a maximum PCE of 8.3%. • ACY co-sensitizer reduces recombination reaction in DSSCs.

Novel D-A-π-A1 Type Organic Sensitizers from 4,7-Dibromobenzo[d][1,2,3]thiadiazole and Indoline Donors for Dye-Sensitized Solar Cells.

Two novel D-A-π-A1 metal-free organic dyes of the KEA series containing benzo[d][1,2,3]thiadiazole (isoBT) internal acceptor, indoline donors fused with cyclopentane or cyclohexane rings (D), a thiophene as a π-spacer, and a cyanoacrylate as an anchor part were synthesized. Monoarylation of 4,7-dibromobenzo[d][1,2,3]thiadiazole by Suzuki-Miyamura cross-coupling reaction showed that in the case of indoline and carbazole donors, the reaction was non-selective, i.e., two monosubstituted derivatives were isolated in each case, whereas only one mono-isomer was formed with phenyl- and 2-thienylboronic acids. This was explained by the fact that heterocyclic indoline and carbazole fragments are much stronger donor groups compared to thiophene and benzene, as confirmed by cyclic voltammetry measurements and calculation of HOMO energies of indoline, carbazole, thiophene and benzene molecules. The structure of monoaryl(hetaryl) derivatives was strictly proven by NMR spectroscopy and X-ray diffraction. The optical and photovoltaic properties observed for the KEA dyes showed that these compounds are promising for the creation of solar cells. A comparison with symmetrical benzo[c][1,2,3]thiadiazole dyes WS-2 and MAX114 showed that the asymmetric nature of benzo[d][1,2,3]thiadiazole KEA dyes leads to a hypsochromic shift of the ICT band in comparison with the corresponding benzo[c][1,2,5]thiadiazole isomers. KEA dyes have a narrow HOMO-LUMO gap of 1.5–1.6 eV. Amongst these dyes, KEA321 recorded the best power efficiency (PCE), i.e., 5.17%, which is superior to the corresponding symmetrical benzo[c][1,2,3]thiadiazole dyes WS-2 and MAX114 (5.07 and 4.90%).

The Use of Optical Coherence Tomography to Demonstrate Dark and Light Adaptation in a Live Moth.

To work effectively, the eyes of nocturnal insects have a problem they must overcome. During the night, the light levels are low, so their eyes need to be very sensitive; but they also need a way of adapting to environmental light conditions, and protecting those sensitive organs, if a bright light is encountered. Human eyes have a pupil that changes size to regulate light input to the eye. Moths (Lepidoptera) use a light absorbing pigment that moves position to limit the light within the eye. This pigment migration is difficult to record because it is a dynamic process and will only occur in a live moth. This paper presents the first use of Ocular Coherence Tomography as a method of viewing anatomical detail in a compound eye. This is noninvasive and does not harm the insect. To demonstrate the effectiveness, this article documents the dynamic process of light adaptation within a moth’s eye.

Liposomal Form of 2,4-Dinitrophenol Lipophilic Derivatives as a Promising Therapeutic Agent for ATP Synthesis Inhibition.

Mitochondrial uncoupler 2,4-dinitrophenol (2,4-DNP) is a promising antidiabetic and antiobesity agent. Its clinical use is limited by a narrow dynamic range and accumulation in non-target sensitive organs, which results in whole-body toxicity. A liposomal formulation could enable the mentioned drawbacks to be overcome and simplify the liver-targeted delivery and sustained release of 2,4-DNP. We synthesized 2,4-DNP esters with carboxylic acids of various lipophilic degrees using carboxylic acid chloride and then loaded them into liposomes. We demonstrated the effective increase in the entrapment of 2,4-DNP into liposomes when esters were used. Here, we examined the dependence of the sustained release of 2,4-DNP from liposomes on the lipid composition and LogPoct of the ester. We posit that the optimal chain length of the ester should be close to the palmitic acid and the lipid membrane should be composed of phospholipids with a certain phase transition point depending on the desired release rate. The increased effect of the ATP synthesis inhibition of the liposomal forms of caproic and palmitic acid esters compared to free molecules in liver hepatocytes was demonstrated. The liposomes’ stability could well be responsible for this result. This work demonstrates promising possibilities for the liver-targeted delivery of the 2,4-DNP esters with carboxylic acids loaded into liposomes for ATP synthesis inhibition.

Protocol for reducing radiation exposure during pediatric thoracic radiography

IntroductionThis work aims to assess if the anode position during chest radiography of pediatric patients with heart congenital disease (HCD) influences medical image results. The approach is to reverse the orientation of the x-ray tube, with the anode end directed towards the patient's face (anode-heel effect). MethodsFive specialists analyzed 48 images, 24 from the control group (CG) and 24 with the anode end directed towards the patients' face (experimental group, EC). An ionization chamber was used to assess radiation dose received by sensitive organs. ResultsThe specialists considered both CG and EC images acceptable. But, the EC group's dose evaluation revealed that the thyroid received 12% less radiation and the gonads presented a 5.9% reduction. Based on the results, a new protocol was developed. Discussion/conclusionThe standardization of radiographic imaging procedures will reduce acquisition errors, resulting in adequate images in pediatric patients with HCD with less radiation dose, thus increasing patient safety and extending the life of the equipment.

Kharakterystyka klinichno-laboratornykh pokaznykiv vmistu mahniiu u syrovattsi krovy vahitnykh iz rannim hestozom riznoho stupenia tiazhkosty

Introduction. Early gestosis is a pathological pregnancy state linked to the development of a fertilized egg or its elements and is characterized by several symptoms. In today’s conditions, the frequency of early gestosis is observed in 60.0-80.0 % of pregnant women, and the need for hospitalization and special treatment occurs in 12.0-17.8 % of pregnant women. According to statistics, up to 90.0 % of pregnant women suffer from nausea and vomiting of varying severity. One of the main issues of medical care for pregnant women with early preeclampsia, in addition to the number of episodes of vomiting during the day, is the presence and severity of micronutrient and vitamin imbalance, which should be inevitable due to nutritional deficiencies due to incontinence and loss of micronutrients with vomiting. One of the key moments of vomiting in pregnant women is expressed misbalance in microelements, especially magnesium (Mg). Mg is necessary for vitamin D biosynthesis, transportation, and activation which is one of the key factors determining the effectiveness of our immune system. Mg participates in vitamin D metabolism, normalizes it, and increases the sensitivity of the target organs. Magnesium has a significant role in immune response as a cofactor for immunoglobulin synthesis and other processes associated with T- and B-cells function is a natural antistress factor that slows down excitation of the central nervous system. The prospects of magnesium insufficiency influencing the severity of early gestosis are poorly studied, which became the reasoning for this study. The aim of the study. To characterize clinical and laboratory indices of magnesium levels in blood serum in pregnant women with early gestosis of different severity grades. Materials and methods. We examined 150 women, 100 ones (the main group) with signs of early gestoses: 41 females with mild signs, 37 women with moderate signs, 22 ones with severe signs, and 50 females (the control group) with the physiologic course of the first trimester of pregnancy. We considered the patient’s complaints, information from case history, physical examination data, common laboratory tests, and ultrasound imaging. The evaluation of Mg deficit was performed according to an adapted standardized score that was used in the international medical practice according to the scale of deficit signs and the Mg levels in blood serum were tested. The reference values of normal Mg levels in blood serum were 0.80-0.85 mmol/L. The statistical analysis of the results was performed using methods of variability with the help of MS Excel and Statistica SPSS10.0 for Windows. Results. According to the results of the questionnaire, the women from the main group mostly presented the Mg deficit and only 17 (17.0%) of pregnant females had no Mg deficit; at the same time, the pregnant women presented Mg insufficiency in 7 (14.0%), and Mg deficit was observed only in 1 (2%) case. the gotten results showed that at increasing gestosis severity, Mg deficit frequency in blood serum increases as well. The analysis of Mg indices in blood serum and using the questionnaire for Mg deficit allowed the determination significant prevalence of magnesium deficit. Conclusion. Most women aged 18-40 years with single live intrauterine pregnancy at 4-12 weeks and signs of early gestosis present magnesium insufficiency and deficit and the frequency of such cases increases with higher severity of early gestosis.

α-C–H Photoalkylation of a Glucose Derivative in Continuous Flow

AbstractSite-selective photoalkylation is a powerful strategy to extend the carbon framework of carbohydrates, otherwise often attainable only through laborious syntheses. This work describes the adaptation and upscaling of the photoalkylation of a glucose derivative as a continuous flow process. The reported iridium catalyst is replaced by an organic sensitizer and the reaction has been carried out on 40-gram scale.

Environmental Impact of Radiation Emitted from Radionuclide Across Southern Borno, Nigeria Using Inspector Alert Nuclear Radiation Monitor

Radiation association with the body produces micro sub-cellular-level effects that may course cellular responses and, in the accumulation, may produce macro observable health effects on some organs or tissues. This work aimed to check the environmental impact of radiation emitted from radionuclide across southern Borno, Nigeria using Inspector Alert Nuclear Radiation Monitor. Finding of this study have revealed that the mean Dorgan values for the lungs, ovaries, bone marrow, testes, kidney, liver and whole body for different local governments of southern Borno are 0.065, 0.059, 0.070, 0.083, 0.063, 0.046 and 0.069 mSv/y respectively. From the findings presented, it can be concluded that the background radiation in Southern Borno is not an issue of health concern in regards to sensitive organs and may not course immediate health effect except on excessive exposure which may cause cancer to the indoor members on approximately seventy years of exposure. It is therefore, advised or recommended that the government encourage regular researches of such for easy control of the health effects.

Natural radionuclide concentration and associated health hazard indices in coal samples from Okobo Coal Mine, Nigeria

Background: Mining activities of coal have the capacity to raise the level of natural radionuclide concentration in our environment. This exposes human population to ionizing radiations with their associated health hazards. This study was aimed at measuring natural radionuclide concentration of 226Ra, 232Th and 40K, and their associated health hazard indices in coal samples from Okobo coal mine. Materials and Methods: The survey design adopted for this study was the cross sectional type. Coal samples totaling ten (10) in number, were randomly collected from the coal mine. The sampled coal was analyzed at the University of Ibadan, in the laboratory of the National Institute of Radiation Protection and Research (NIRPR), using high resolution spectrometry technique, with high purity germanium (HPGe) detectors. Results: The obtained results revealed that the radionucide concentration of 226Ra in the sampled coal recorded slightly higher value (21.34±7.94 Bq/kg) than global average of 20 Bq/Kg. However, the recorded values for 232Th (13.61±5.08 Bq/kg) and 40K (20.91±15.77 Bq/kg) fall below the global average value of 20 and 50 Bq/Kg respectively. All calculated radiological hazard parameters recorded lower values than the global permissible value but for annual gonadal dose equivalent (AGDE) which recorded significantly higher value (407.74 mSv/yr) than the world acceptable limit of 300 mSv/yr. Conclusion: The activity concentration of 226Ra for Okobo coal sample recorded a unit mean value higher than the global average, however the recorded values for 232Th and 40K fall below global permissible values. All radiological health hazards recorded lower values than the precautionary safe limit but for annual gonadal equivalent dose which recorded significantly higher value than the global permissible limit. This implies that both staff and residents of the community could be exposed to radiological threat, which might affect the functionality of their sensitive organs if prolonged and cumulative exposure is not avoided.

Comparison of product safety data sheet ingredient lists with skin irritants and sensitizers present in a convenience sample of light-curing resins used in additive manufacturing

Material jetting and vat photopolymerization additive manufacturing (AM) processes use liquid resins to build objects. These resins can contain skin irritants and/or sensitizers but product safety data sheets (SDSs) might not declare all ingredients. We characterized elemental and organic skin irritants and sensitizers present in 39 commercial products; evaluated the influence of resin manufacturer, system, color, and AM process type on the presence of irritants and sensitizers; and compared product SDSs to results. Among all products, analyses identified 23 irritant elements, 54 irritant organic substances, 22 sensitizing elements, and 23 sensitizing organic substances; SDSs listed 3, 9, 4, and 6 of these ingredients, respectively. Per product, the number and total mass (an indicator of potential dermal loading) of ingredients varied: five to 17 irritant elements (8.32–4756.65 mg/kg), one to 17 irritant organics (3273 to 356,000 mg/kg), four to 17 sensitizing elements (8.27–4755.63 mg/kg), and one to seven sensitizing organics (15–382,170 mg/kg). Median numbers and concentrations of irritants and sensitizers were significantly influenced by resin system and AM process type. The presence of undeclared irritants and sensitizers in these resins supports the need for more complete information on product SDSs for comprehensive dermal risk assessments.

Process Engineering of Semitransparent DSSC Modules and Panel Incorporating an Organic Sensitizer

Among the technologies adopted in the building‐integrated photovoltaics sector, dye‐sensitized solar cells appear very attractive because of unique features like tunable color and good transparency. However, the prospect of their low‐cost fabrication is realistic only if reliable and scalable processes under real manufacturing conditions (i.e., pilot line and/or plant factory) are designed, developed, and optimized for large‐area, efficient, and stable devices. Herein, a highly reproducible process is shown based on the deposition of different inks by screen‐printing technique to realize twenty modules (400 cm2) and one panel (0.2 m2) incorporating an organic sensitizer. Module design considers the resistive losses caused by electron transport, the durability of the device and its aspect ratio (&gt;70%). The module champion efficiency is 5.1% with 35.7% transparency (average visible transmittance), and its stability is determined to be &gt;1000 h according to two International Summit on Organic Photovoltaic Stability (ISOS) protocols (D‐2 and L‐1). The modules show no structural failures, electrolyte leakage, or other signs of degradation. The consistency of the gap between photo‐ and counter‐electrodes before and after stress is demonstrated. An industrial lamination process to realize a panel with an outdoor efficiency of 2.7% at 60 °C tilt angle is adopted.

Polymer Coated Polymeric (PCP) Microneedles for Controlled Delivery of Drugs (Dermal and Intravitreal)

Microneedles are used to deliver drugs topically across the skin and mucous membranes. Dissolvable microneedles are made using soluble polymers, which disintegrates in the tissue and release the entire payload instantaneously including the polymer construct. Often, a slow release of drug into the tissue is desirable to overcome the severity of side effects at the site of administration as well as systemic adverse effects. In addition, controlled release of active pharmaceutical ingredient (API) only (not the excipients) is safe and effective particularly when the drug delivery is intended to sensitive organs like the eye. In this project, the feasibility of fabricating polymer coated polymeric (PCP) microneedles to achieve a gradual release of only the active ingredient from the device was investigated. The potential application of such PCP microneedles in the dermal and intravitreal drug delivery was also explored using animal tissue models. The PCP microneedles were found to be intact even after prolonged contact with the release medium. The time at which 50% (T50%) of dextran (10 K) was released in case of microneedles prepared using 20% of core polymer (PVP-K30) was about 15 min versus less than 5 min in the case of uncoated microneedles. Whereas when the core polymer concentration was increased to 50%, the T50% was increased to 90 min. The rate of release depended on the polymer molecular weight grade. The rate of drug release was not influenced by the total amount of concentration of dextran. The PCP microneedles of lidocaine hydrochloride could constantly release the drug for up to 9 h in the skin tissue. Likewise, the PCP microneedles infused voriconazole, intravitreally for 6 h.

Microstructural assessment of organs and tissues in experimental immunosuppression and correction in animals

Abstract. Modern technological conditions of keeping and exploitation of animals and poultry do not exclude the negative impact of stress on their body. This leads to a decrease in the body’s resistance, an increase in morbidity and mortality. In addition, the quantity and quality of the products obtained are reduced. Stress prevention helps to increase the natural resistance of the body. The search for effective means of preventing stress reactions of the body in animal husbandry and poultry farming is an urgent problem of practical veterinary medicine. Polymineral feed additives of natural and artificial origin may exhibit adaptogenic properties. The purpose of this study was to give a microhistochemical assessment of the effectiveness of a mineral feed additive on some internal organs during experimental immunosuppression in laboratory animals. In the conditions of experimental immunosuppression, to identify the effect of a feed additive on the structure of organ cells and their metabolism. Materials and methods. To confirm the effectiveness of the mineral adaptogen, histological, morphometric and histochemical studies of stress-determining organs (adrenal glands), organs of excretion of metabolic products (kidneys) and the central organ of homeostasis (liver) were performed. As a result of the conducted studies, the organoprotective role of the mineral adaptogen was revealed. The most sensitive organs to the action of adverse factors (liver, kidneys, adrenal glands) have been identified. Morphometrically determined the reliability of morphological changes in them. During prophylactic feeding of mineral adaptogen in the studied organs, the revealed changes did not have total destruction, approaching the structure and metabolic processes in cells to the structure of these organs in intact animals. Scientific novelty. For the first time, a comparative microstructural, histochemical and morphometric assessment of some internal organs in the body of laboratory animals under conditions of artificially induced immunosuppression was carried out, confirming the organoprotective effect of a mineral adaptogen – a feed mineral additive of domestic production.

Histological Alteration of Green Mussel Perna viridis Organs Exposed to Microplastics

Microplastic in the oceans might interfere the health of marine organisms, including the green mussels (Perna viridis). This is due to microplastic accumulation in mussels organs, such as gills, hepatopancreas, and gonads. Therefore, tissue alteration is a good indicator for ecological risk analysis and other ecotoxicological study activities. Green mussels with shells 4.1 to 5.0 cm in length were collected from Mandalle waters, Pangkep Regency (Pangkajene Islands), Indonesia. Green mussels were exposed for seven days to microplastic with concentrations of 0.05 (A), 0.5 (B), and 5 (C) g/L. The results showed that the higher the concentration of microplastics exposed to the green mussel, the higher the accumulation of microplastics in the body of the mussel, within the tested concentrations. The increased concentration of microplastics increased the level of tissue alteration in the gills, hepatopancreas, and gonads, with the most sensitive organ being the hepatopancreas. Overall, the study confirmed that the histological assay of mussel organs could be used as a biomarker in ecotoxicological studies.

Comparative analysis of residual neurovirulence of vaccine and low attenuated rubella virus (Matonaviridae: Rubivirus: Rubella virus) strains in the experiments on the macaque rhesus (Macaca mulatta) monkeys

Rubella is currently an infection controlled by specific prophylaxis. Not only the right vaccine prophylaxis strategy and tactics, but also the use of effective and safe vaccine preparations is crucial for the elimination of this disease.The aim of the investigation was to study the morphological and pathogenetic patterns of changes developing in the central nervous system (CNS) and internal organs of monkeys (Haplorhini) during intracerebral inoculation with 2 strains of rubella virus (Matonaviridae: Rubivirus: Rubella virus) (RV): highly attenuated Orlov-B, and low attenuated Orlov-14. In the experiments, seronegative rhesus macaque monkeys (Macaca mulatta) weighing 3.3-5.1 kg (n = 7) were used. Neurovirulence of the strains was determined by a complex of clinical, pathomorphological, and virological methods. It was found that during attenuation, the Orlov-B strain lost the ability to replicate in CNS cells and induce moderate/expressed specific changes in them, as well as to overcome the blood-brain barrier and cause the damage of sensitive organs and tissues. This fact indicates a low level of residual neurovirulence of the vaccine strain. The results obtained in this study regarding the clinical symptoms of CNS lesions and the nature of the pathological process in its tissues in experimental animals can be significant for the improvement of safety control of live rubella vaccines. These data indicate that the Orlov-B strain can be considered as a candidate strain for further study on the development of a rubella vaccine based on the domestic vaccine strain.