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1.
Clin Nephrol ; 101(3): 123-131, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38156780

ABSTRACT

AIM: Acute kidney injury (AKI) worsens the outcome in a significant number of hospitalized patients. Risk models mainly address cardiac surgery, while significantly less attention is paid to AKI after major abdominal surgery (MAS). This study aims to evaluate the incidence, along with risk factors, and intrahospital outcomes of AKI after MAS. MATERIAL AND METHODS: Our retrospective study included 200 adult patients treated with MAS (in the same institution). Exclusion criteria were obstructive nephropathy, contrast-induced nephropathy, and dialysis dependence whether due to end-stage renal disease (ESRD) or AKI before MAS. Data on preoperative, intraoperative, as well as postoperative variables were collected from patients' medical history and electronic medical records. RESULTS: AKI was diagnosed in 33 (16.5%) patients, with 2 patients treated with hemodialysis. The multivariate logistic regression model showed that the number of intraoperative blood transfusions (p = 0.01), pneumonia (p < 0.001), and vasoactive drug use (p = 0.02) were independently associated with postoperative AKI. Each blood transfusion administered increased the risk of developing AKI by 1.41, vasoactive drug use by 4.13, and the risk of AKI in those with pneumonia was 15.32 times higher. The lethal outcome was observed significantly more frequently in patients with AKI (39.4 vs. 4.8%, p < 0.001). CONCLUSION: Identification of independent predictors of AKI after MAS such as the number of transfusions during surgery, sepsis, pneumonia, and the need for vasoactive drug therapy could help prevent AKI and lower the probability of lethal outcomes after MAS.


Subject(s)
Acute Kidney Injury , Pneumonia , Adult , Humans , Retrospective Studies , Renal Dialysis/adverse effects , Risk Factors , Acute Kidney Injury/epidemiology , Acute Kidney Injury/etiology , Pneumonia/complications , Postoperative Complications/epidemiology , Postoperative Complications/etiology
2.
Food Sci Nutr ; 11(10): 6393-6402, 2023 Oct.
Article in English | MEDLINE | ID: mdl-37823160

ABSTRACT

Laetiporus sulphureus (Bull.) Murrill is a well-known edible mushroom consumed in nutrition as delicacy. It has been used in traditional medicine because of its beneficial effects on human wellness, such as antimicrobial, antioxidant, and anticancer potential. The present study determined the phenolic profile of Laetiporus sulphureus ethanolic extract (LSE) by high-performance liquid chromatographic method. Tolerance of two probiotic bacterial strains Lactiplantibacillus plantarum 229v, Bifidobacterium animalis subsp. lactis and probiotic yeast Saccharomyces boulardii on LSE was analyzed in terms of viability and biofilm formation. Effects of extract on colorectal (HCT-116) and cervical (HeLa) cancer cells viability was determined using MTT test in concentration range: 1-500 µg/mL after 24 and 72 h. Redox parameters (superoxide anion radicals, nitrites, and reduced glutathione) were evaluated using NBT, Griess, and GSH assays in the concentration range of 1-500 µg/mL after 24 and 72 h. Antimigratory activity was determined by wound healing method using selected concentrations of 10 and 50 µg/mL after 24 h. Untreated cells were considered as control. As control cell line, we used healthy fibroblasts (MRC-5). Our results demonstrated abundance of LSE in phenolics, with rosmarinic acid as the main component. LSE induced low tolerance of tested planktonic probiotic strains, with no affection on their ability to form biofilm. No significant cytotoxicity on tested cancer cells was observed, with prooxidative and antimigratory effects noticed. Extract exerted significant antimigratory activity on cancer cells without effect on planktonic and probiotic cultures in biofilm. These results indicate potential application of Laetiporus sulphureus ethanolic extract as natural protector of probiotics with prominent ability to suppress cancer cell motility.

3.
Nutrients ; 15(9)2023 Apr 24.
Article in English | MEDLINE | ID: mdl-37432214

ABSTRACT

In previous publications, we pointed out the importance of mannosylation of fibrinogen for the development of cardiovascular complications and fucosylation as a predictor of peritoneal membrane dysfunction in patients on peritoneal dialysis (PD). After a follow-up period of 30 months from the onset of the COVID-19 pandemic, we evaluated the significance of 1,25-dihydroxyvitamin D3 (calcitriol) therapy, primary disease, biochemical and hematologic analyzes, and previously performed glycan analysis by lectin-based microarray as predictors of mortality in this patient group. After univariate Cox regression analysis, diabetes mellitus (DM) and calcitriol therapy were found to be potential predictors of mortality. Additional multivariate Cox regression analysis confirmed that only DM was a predictor of mortality. Nevertheless, the use of calcitriol in therapy significantly reduced mortality in this patient group, as shown by the Kaplan-Meier survival curve. The presence of DM as a concomitant disease proved to be a strong predictor of fatal outcome in PD patients infected with SARS-CoV-2. This is the first study to indicate the importance and beneficial effect of calcitriol therapy on survival in PD patients with COVID-19 infection. In addition, this study points to the possibility that adverse thrombogenic events observed in PD patients during the pandemic may be caused by aberrant fibrinogen glycosylation.


Subject(s)
COVID-19 , Hemostatics , Peritoneal Dialysis , Humans , Calcitriol , Pandemics , SARS-CoV-2 , Peritoneal Dialysis/adverse effects , Fibrinogen
4.
Heliyon ; 9(7): e17664, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37455950

ABSTRACT

Great waste production alongside limited natural resources represents huge environmental and economic problems worldwide. Sustainable waste management and industrial production can reduce pollution and gain some economic benefits. Eco-friendly thermal insulators such as foam glasses can be produced using secondary raw materials in open-loop recycling. Foam glasses were successfully produced using green bottle glass and sugar beet factory lime (SBFL), CaCO3-rich waste as a novel foaming agent. Glass powder was mixed with different amounts of SBFL, uniaxially pressed at 20 MPa, and sintered at different temperatures. The influence of sintering temperature and the addition of a foaming agent was examined. Obtained samples were mechanically, thermally, and microstructurally characterized. Results showed that samples sintered at 800 °C have the best properties. Obtained foam glasses can be used in a variety of industries where thermal insulation, non-flammability, and non-toxic materials are required.

5.
Materials (Basel) ; 16(13)2023 Jul 04.
Article in English | MEDLINE | ID: mdl-37445132

ABSTRACT

The spillage of oil causes severe and long-lasting impacts on both the environment and human life. It is crucial to carefully reconsider the methods and techniques currently employed to recover spilled oil in order to prevent any possible secondary pollution and save time. Therefore, the techniques used to recover spilled oil should be readily available, highly responsive, cost-effective, environmentally safe, and, last but not least, they should have a high sorption capacity. The use of sorbents obtained from natural materials is considered a suitable approach for dealing with oil spills because of their exceptional physical characteristics that support sustainable environmental protection strategies. This article presents a novel sorbent material, which is a composite siloxane foam filled with bentonite clay, aimed at enhancing the hydrophobic and oleophilic behavior of the material. The thermal treatment of bentonite optimizes its sorption capacity by eliminating water, and increasing the surface area, and, consequently, its interaction with oils. In particular, the maximum sorption capacity is observed in kerosene and naphtha for the bentonite clay thermally treated at 600 °C, showing an uptake at saturation of 496.8% and 520.1%, respectively. Additionally, the reusability of the composite foam is evaluated by squeezing it after reaching its saturation point to determine its sorption capacity and reusability.

6.
Chem Biodivers ; 20(7): e202300553, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37329266

ABSTRACT

This is the first study on cuticular wax variability of Abies alba, A.×borisii-regis and A. cephalonica, using 18 native populations from the assumed hybrid zone in the Balkan Peninsula. Presence of 13 n-alkanes with chain-lengths ranging from C21 to C33 , one primary alcohol, two diterpenes, one triterpene and one sterol was determined in hexane extracts of 269 needle samples. The multivariate statistical analyses at the population level entirely failed in supporting circumscription of Balkan Abies taxa and therefore, in identifying hybrid populations. However, performed at the species level, these analyses revealed a certain tendency of differentiation between A. alba and A. cephalonica, while individuals of A.×borisii-regis were largely overlapped by the clouds of both parent species. Finally, the correlation analysis suggested that the observed variation of wax compounds was probably genetically conditioned and that it does not represent an adaptive response to various environmental factors.


Subject(s)
Abies , Plant Leaves , Humans , Plant Leaves/chemistry , Balkan Peninsula , Waxes/analysis , Ethanol
7.
Radiat Prot Dosimetry ; 199(8-9): 941-946, 2023 May 24.
Article in English | MEDLINE | ID: mdl-37225179

ABSTRACT

In accordance with ISO/IEC 17025:2017, the testing laboratory needs to verify its ability to properly perform methods. For radiological testing, the sampling does not affect the results directly, but it has to ensure that sample adequately represents the tested material. To verify the procedure, a sampling of red mud and bauxite ore was conducted. All samples were measured in identical geometry by HPGe spectrometer. The counting rates per unit mass in the recorded spectra were compared. For each measurement series, the mean and standard deviations of respected peaks were calculated, as well as average and standard deviation of all series. The obtained results of each individual series were considered satisfactory, i.e. sampling procedure ensures the representativeness of the bulk material, if it is within ± two standard deviations of the average of the mean values.


Subject(s)
Radioactivity , Radiology , Aluminum Oxide , Industry , Laboratories
8.
Toxics ; 11(4)2023 Apr 05.
Article in English | MEDLINE | ID: mdl-37112572

ABSTRACT

This work presents the natural radioactivity distribution of 21 surface soil samples taken in the city of Novi Sad, Serbia. The analysis for radioactivity was performed using a gas low-level proportional counter for gross alpha and gross beta activity, while the specific activities of radionuclides were determined using HPGe detectors. The gross alpha activity of 20 samples was below the minimum detectable concentration (MDC), while in 1 sample it was 243 Bq kg-1; the gross beta activity ranged from the MDC (11 samples) to 566 Bq kg-1. The gamma spectrometry measurements showed naturally occurring radionuclides 226Ra, 232Th, 40K, and 238U in all investigated samples, with average values (Bq kg-1) of 33.9, 36.7, 513.8, and 34.7, respectively. Natural radionuclide 235U was detected in 18 samples with activity concentrations in the range of 1.3-4.1 Bq kg-1, while in the other 3 samples, the values were below the MDC. The artificial 137Cs radionuclide was detected in 90 percent of the samples, with a maximum value of 21 Bq kg-1, while the other artificial radionuclides were not detected. Based on the obtained concentrations of natural radionuclides, hazard indexes were estimated, and radiological health risk was assessed. The results present the absorbed gamma dose rate in the air, annual effective dose, radium equivalent activity, external hazard index, and lifetime cancer risk.

9.
Int J Mol Sci ; 24(3)2023 Feb 03.
Article in English | MEDLINE | ID: mdl-36769290

ABSTRACT

We analyzed the expression of the serotonin receptors 5-HT1A, 5-HT2A, and 5-HT3A at four different stages of fetal lung development from 12 to 40 weeks of gestation, divided into four groups: the pseudoglandular stage (12-16th week of development; n = 8), the canalicular stage (16th-26th week of development; n = 7), the saccular stage (26th-36th week of development; n = 5), and the alveolar stage (36th-40th week of development; n = 5). The strongest expression of all three receptor types was found in the epithelium of the proximal airways during the pseudoglandular, canalicular, and saccular stages and in a vascular wall. 5-HT1A was also strongly expressed in the smooth muscle cells of the proximal airway. Vascular smooth muscle cells and endothelium occasionally showed a strong expression of 5-HT1A and 5-HT2A. In the alveolar stage, the expression of 5-HT1A, 5-HT2A, and 5-HT3A was detected in both type I (p1) and type II (p2) pneumocytes, with a stronger expression in p2. A significant decrease in percent the 5-HT2A area and in the integrated density was observed at the alveolar stage. On the other hand, a significant decrease in the percentage area but an increase in the integrated density was observed for 5-HT3A toward the alveolar stage, suggesting that a smaller number of cells expressed 5-HT3A but that they (p1 and p2) significantly increased their 5-HT3A expression at the alveolar stage. The results presented provided us with new data on the development and function of the serotonin system in the human fetal lung and gave us insight into their possible involvement in the pathogenesis of lung pathology, particularly that characteristic of the neonatal period.


Subject(s)
Lung , Receptors, Serotonin , Infant, Newborn , Humans , Receptors, Serotonin/genetics , Receptors, Serotonin/metabolism , Lung/metabolism , Fetus/metabolism , Epithelium/metabolism , Serotonin/metabolism , Receptor, Serotonin, 5-HT2A/genetics , Receptor, Serotonin, 5-HT2A/metabolism , Receptor, Serotonin, 5-HT1A/genetics , Receptor, Serotonin, 5-HT1A/metabolism
10.
Oncol Lett ; 25(3): 94, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36817058

ABSTRACT

Oral squamous cell carcinoma (OSCC) is the eighth most common type of cancer in the world. Knowledge of prognostic factors of survival in OSCC is key. Several clinical and pathological prognostic factors have been investigated to develop a prognostic model of survival for patients with oral cancer. The present study focused on the association between pathological tumor volume (PTV) and overall survival time in patients with OSCC, regardless of cervical nodal status. The present study was a prospective study and covered 65 consecutive patients who received surgical treatment for oral cancer. The PTV was calculated according to dimensions of the postoperative specimen. Other pathological parameters as perineural and perivascular tumor spreading and extra-nodular propagation were also determined. The data were analyzed using the IBM SPSS 25.0 software. Cox PH regression model was built to analyze association between the PTV and survival time. Survival time was defined as the period from surgery to a target event or last contact. The results of the present study showed that PTV >4.24 cm3 was significantly associated with shorter overall survival time in patients with OSCC. The PTV value was higher in patients with metastasis and in patients with higher pathological tumor and node stage. In conclusion, PTV was an important pathological prognostic factor for survival in patients with OSCC.

11.
Medicine (Baltimore) ; 101(38): e30732, 2022 Sep 23.
Article in English | MEDLINE | ID: mdl-36197223

ABSTRACT

INTRODUCTION: Mucinous adenocarcinoma (MAC) is a rare type of cancer in which more than 50% of the tumor is composed of extracellular mucin and malignant epithelial cells. MACs account for only 1.8% of all breast cancer cases. Most breast cancers present as localized diseases and are well-differentiated. Breast MAC has a better 5- and 10-year survival rate than ductal and lobular carcinomas. Distant metastasis in breast MAC is rare, especially in the oral cavity. Only 1% of all oral malignancies present with metastases to the oral cavity. The bony structures are more involved than the soft tissues. Involvement of the oral soft tissue is rare, accounting for less than 0.1% of oral metastases. CASE DESCRIPTION: This report describes a rare case of mucinous breast adenocarcinoma with metastasis to the mandibular molar region. Diagnosis was established based on anamnesis, clinical presentation, tumor biopsy, computed tomography, mammography, and core biopsy of the breast tumor. The patient was sent to the oncology committee for breast disease where chemotherapy was indicated. DISCUSSION: The clinical presentation of oral metastasis is not pathognomonic, and pyogenic granuloma, periodontal abscesses, sarcomas, and squamous carcinoma must be considered in the differential diagnosis. This is a rare case of oral metastasis of breast MAC, which was indicated for detection of the primary tumor.


Subject(s)
Adenocarcinoma , Breast Neoplasms , Carcinoma, Lobular , Adenocarcinoma/pathology , Breast Neoplasms/diagnosis , Breast Neoplasms/pathology , Female , Gingiva/pathology , Humans , Melanoma , Mucins , Skin Neoplasms , Melanoma, Cutaneous Malignant
12.
Chem Biodivers ; 19(6): e202200235, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35507018

ABSTRACT

This study focused on the essential oils (EOs) isolated from needles with twigs of three indigenous Balkan Abies species (A. alba, A. × borisii-regis and A. cephalonica) regarding their chemical composition, antimicrobial activity and toxicity toward crustaceans and insects. Even though distinct phytochemical profiles of dominant volatiles were revealed for each species, ß-pinene and α-pinene represented the first two major volatiles in all three EOs. Antimicrobial activity of EOs has shown inhibitory effect against all 17 studied strains (ATCC and respiratory isolates) in the range of 0.62-20.00 mg/mL (MICs). Further, all three EOs exhibited strong toxicity (LC50 <100 µg/mL) in Artemia salina lethality bioassay, but with significant differences that depended on the EO type. Additionally, tested EOs have shown a certain level of toxicity against Drosophila melanogaster, mostly at the highest tested concentration (3 %) which caused significant prolongation of developmental time, larvicidal effect and pupal mortality. In the three biological assays performed, there was no observed inhibitory effect or weakest activity for A. alba EO. Further, A. cephalonica EO has shown the highest levels of antimicrobial activity and toxicity toward A. salina, while in relation to the insecticidal potential, A. cephalonica and A. × borisii-regis EOs exhibited similar level of toxicity against D. melanogaster.


Subject(s)
Abies , Anti-Infective Agents , Oils, Volatile , Animals , Anti-Infective Agents/chemistry , Anti-Infective Agents/toxicity , Artemia , Balkan Peninsula , Drosophila melanogaster , Oils, Volatile/chemistry , Oils, Volatile/toxicity
13.
J Toxicol Environ Health A ; 85(17): 699-714, 2022 09 02.
Article in English | MEDLINE | ID: mdl-35591784

ABSTRACT

It is well-known that mushrooms of the genus Lactarius constitute a natural food resource providing health benefits as a nutritient. This genus contains 4 mushrooms identified as L. deliciosus, L. volemus, L. sanguifluus, L. semisanguifluus and L. piperatus which were collected in Serbia. The aim of this study aimed was to identify and characterize the content of phenolic compounds and examine the antioxidant potential of 5 wild edible mushrooms. L. sanguifluus contained the highest content of total phenol compounds (75.25 mg gallic acid equivalents (GAE) per g dry extract weight (GAE/g DE) and exhibited the greatest antioxidant activity through the ability to remove radicals as evidenced by ABTS assay (8.99 mg of trolox equivalents (TE) per g dry extract weight (mg TE/g DE); total reducing power (TRP) assay mg ascorbic acid equivalents per mg of dry extract weight (0.42 mg AAE/g DE) and CUPRAC (14.23 mg TE /g DE). L. deliciosus methanolic extract produced greatest scavenging of the DPPH radical (46%). The methanol mushroom extracts were screened for in vitro antimicrobial activity against a panel of pathogenic bacterial strains using the microdilution method. Of all the extracts tested, L. sanguifluus extract showed the best antibacterial properties. The cytokinesis block micronucleus assay results for the examined mushrooms demonstrated that extracts at a concentration of 3 µg/ml decreased the number of micronuclei (MN) in the range of 19-49% which is significant bearing in mind that radioprotectant amifostine reduced the frequency of MN by only 16.3%. Data thus demonstrate that the 5 wild edible mushrooms of genus Lactarius contain constituents that are beneficial not only as nutrients but also have the potential as antioxidants, antibacterial and antigenotoxic properties.


Subject(s)
Agaricales , Antioxidants , Agaricales/chemistry , Anti-Bacterial Agents/pharmacology , Antioxidants/chemistry , Antioxidants/pharmacology , Ascorbic Acid , Phenols/chemistry , Plant Extracts/chemistry
14.
Article in English | MEDLINE | ID: mdl-35055485

ABSTRACT

Doses from the exposure to outdoor radon are typically an order of magnitude smaller than those from indoor radon, causing a greater interest on investigation of the latter for radiation protection issues. As a consequence, assessment of radon priority areas (RPA) is mainly based on indoor radon measurements. Outdoor radon measurements might be needed to guarantee a complete estimation of radiological risk and may help to improve the estimation of RPA. Therefore, authors have analysed the available literature on outdoor radon to give an overview of outdoor radon surveys and potential correlation with indoor radon and estimation of RPA. The review has shown that outdoor radon surveys were performed at much smaller scale compared to indoor radon. Only a few outdoor radon maps were produced, with a much smaller density, covering a larger area, and therefore putting doubt on the representativeness of this data. Due to a large variety of techniques used for outdoor radon measurements and requirement to have detectors with a high sensitivity and resistance to harsh environmental conditions, a standardised measurement protocol should be derived. This is no simple endeavour since there are more applications in different scientific disciplines for outdoor radon measurements compared to indoor radon.


Subject(s)
Air Pollutants, Radioactive , Air Pollution, Indoor , Radiation Monitoring , Radon , Air Pollutants, Radioactive/analysis , Air Pollution, Indoor/analysis , Housing , Radon/analysis
15.
Entropy (Basel) ; 23(12)2021 Dec 20.
Article in English | MEDLINE | ID: mdl-34946005

ABSTRACT

Driven by the need for the compression of weights in neural networks (NNs), which is especially beneficial for edge devices with a constrained resource, and by the need to utilize the simplest possible quantization model, in this paper, we study the performance of three-bit post-training uniform quantization. The goal is to put various choices of the key parameter of the quantizer in question (support region threshold) in one place and provide a detailed overview of this choice's impact on the performance of post-training quantization for the MNIST dataset. Specifically, we analyze whether it is possible to preserve the accuracy of the two NN models (MLP and CNN) to a great extent with the very simple three-bit uniform quantizer, regardless of the choice of the key parameter. Moreover, our goal is to answer the question of whether it is of the utmost importance in post-training three-bit uniform quantization, as it is in quantization, to determine the optimal support region threshold value of the quantizer to achieve some predefined accuracy of the quantized neural network (QNN). The results show that the choice of the support region threshold value of the three-bit uniform quantizer does not have such a strong impact on the accuracy of the QNNs, which is not the case with two-bit uniform post-training quantization, when applied in MLP for the same classification task. Accordingly, one can anticipate that due to this special property, the post-training quantization model in question can be greatly exploited.

16.
Environ Sci Technol ; 55(20): 13834-13848, 2021 10 19.
Article in English | MEDLINE | ID: mdl-34585576

ABSTRACT

From early April 2020, wildfires raged in the highly contaminated areas around the Chernobyl nuclear power plant (CNPP), Ukraine. For about 4 weeks, the fires spread around and into the Chernobyl exclusion zone (CEZ) and came within a few kilometers of both the CNPP and radioactive waste storage facilities. Wildfires occurred on several occasions throughout the month of April. They were extinguished, but weather conditions and the spread of fires by airborne embers and smoldering fires led to new fires starting at different locations of the CEZ. The forest fires were only completely under control at the beginning of May, thanks to the tireless and incessant work of the firefighters and a period of sustained precipitation. In total, 0.7-1.2 TBq 137Cs were released into the atmosphere. Smoke plumes partly spread south and west and contributed to the detection of airborne 137Cs over the Ukrainian territory and as far away as Western Europe. The increase in airborne 137Cs ranged from several hundred µBq·m-3 in northern Ukraine to trace levels of a few µBq·m-3 or even within the usual background level in other European countries. Dispersion modeling determined the plume arrival time and was helpful in the assessment of the possible increase in airborne 137Cs concentrations in Europe. Detections of airborne 90Sr (emission estimate 345-612 GBq) and Pu (up to 75 GBq, mostly 241Pu) were reported from the CEZ. Americium-241 represented only 1.4% of the total source term corresponding to the studied anthropogenic radionuclides but would have contributed up to 80% of the inhalation dose.


Subject(s)
Air Pollutants, Radioactive , Chernobyl Nuclear Accident , Fires , Wildfires , Air Pollutants, Radioactive/analysis , Cesium Radioisotopes/analysis , Europe , Ukraine
17.
Phytochemistry ; 183: 112612, 2021 Mar.
Article in English | MEDLINE | ID: mdl-33440298

ABSTRACT

Seventeen native fir populations from the presumed zones of natural hybridization in the Balkan Peninsula were analyzed using headspace needle volatiles and GC-MS/FID analyses. The multivariate statistical analyses revealed clear differentiation between populations of Abies alba and A. cephalonica, suggesting that Silver and Greek Fir are characterized by distinct volatile profiles. Three populations from northern and central Greece identified as A. x borisii-regis shared the volatile profiles with both of the supposed parent species, whereby profile frequencies changed clinally along the latitudinal gradient connecting the ranges of parent species. Therefore, observed geographical distribution of volatile entities support the hypothesis that studied A. x borisii-regis populations are of secondary origin, formed by hybridization between A. alba and A. cephalonica. All three populations should be included in conservation projects, as the genetic constitution of these polymorphic fir populations may contain useful genetic variation necessary for survival regarding the future environmental challenges in this area.


Subject(s)
Abies , Balkan Peninsula , Greece , Hybridization, Genetic
19.
J Mol Model ; 26(10): 275, 2020 Sep 21.
Article in English | MEDLINE | ID: mdl-32959185

ABSTRACT

The pattern of cyclic conjugation was thoroughly studied in the series of N- and P-acenaphthylene derivatives using several different aromaticity indices: the energy effect (ef), multicenter delocalization index (MCI), harmonic oscillator model of aromaticity (HOMA) index, and nucleus independent chemical shifts (NICS). The Kekulé-structure-based reasoning predicts that there would be no cyclic conjugation in the "empty" five-membered heteroatom-containing rings in the studied molecules. It was found that according to the ef, MCI, and HOMA values, the extent of cyclic conjugation in the pentagonal rings is strongly influenced by the number and mutual arrangement of the hexagonal rings. In addition, it was revealed that in some of the examined molecules, the intensity of cyclic conjugation in the "empty" pentagons is even stronger than that of some hexagonal rings within the same molecule. The obtained results refute what one would expect based on "chemical intuition," which is usually strongly rooted to the Kekulé structures.Graphical abstract.

20.
Appl Radiat Isot ; 165: 109335, 2020 Nov.
Article in English | MEDLINE | ID: mdl-32777742

ABSTRACT

Open-faced charcoal canisters have been used for radon measurements for over 40 years. This method is sensitive to temperature, changing radon concentrations, humidity and other parameters, but a comprehensive study dealing with the influence quantities and measurement uncertainty was not available in literature. In this paper, all the identified influence quantities are discussed in detail, uncertainty budget is developed, good practice and bad practice examples are introduced and new recommendations are proposed to optimize the method and reduce uncertainty.

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