Peculiarities of Ga and Te incorporation in glassy arsenic selenides

International audienceEffect of simultaneous Ga and Te addition on the structure of As2Se3 glasses is studied using X-ray photoelectron spectroscopy (XPS), extended X-ray absorption fine structure (EXAFS) and Raman techniques. It is shown that most of As, Se and Te atoms build a covalent network according to their main valences. Three-fold coordinated As atoms form pyramidal structural units, which are connected via bridges of two-fold coordinated chalcogen atoms (Se, Te). On the other hand, coordination of Ga in glassy samples is found to be greater than three, as expected from its valence, increasing with Te content. Some of the As atoms appear to be converted into four-fold coordinated state at low Te concentration, while a fraction of Te and, possibly, Se atoms are thought to exist in a singly-coordinated (terminal) state in the vicinity of Ga in the samples with higher Te concentration

Intermediate Phases, structural variance and network demixing in chalcogenides: the unusual case of group V sulfides

We review Intermediate Phases (IPs) in chalcogenide glasses and provide a structural interpretation of these phases. In binary group IV selenides, IPs reside in the 2.40 < r < 2.54 range, and in binary group V selenides they shift to a lower r, in the 2.29< r < 2.40 range. Here r represents the mean coordination number of glasses. In ternary alloys containing equal proportions of group IV and V selenides, IPs are wider and encompass ranges of respective binary glasses. These data suggest that the local structural variance contributing to IP widths largely derives from four isostatic local structures of varying connectivity r; two include group V based quasi-tetrahedral (r = 2.29) and pyramidal (r = 2.40) units, and the other two are group IV based corner-sharing (r = 2.40) and edge-sharing (r = 2.67) tetrahedral units. Remarkably, binary group V (P, As) sulfides exhibit IPs that are shifted to even a lower r than their selenide counterparts; a result that we trace to excess Sn chains either partially (As-S) or completely (P-S) demixing from network backbone, in contrast to excess Sen chains forming part of the backbone in corresponding selenide glasses. In ternary chalcogenides of Ge with the group V elements (As, P), IPs of the sulfides are similar to their selenide counterparts, suggesting that presence of Ge serves to reign in the excess Sn chain fragments back in the backbone as in their selenide counterparts

The reproductive function of women with infertility after suffering COVID-19 infection

The aim was to assess the status of reproductive function of infertile women after COVID-19 infection. Materials and methods. The thorough examination included 120 patients who appealed to the reproductive clinic for infertility treatment. These women were divided into 2 groups: the main group - 80 women after COVID-19 infection (exclusion criteria - patients solely with the male factor of infertility), and the comparison group included 40 patients without COVID-19 infection in anamnesis. Results. Patients with infertility and "long-COVID" have more pronounced disorders of the reproductive function compared to women without history of COVID-19 infection, namely: a decrease in the ovarian reserve (28.8% vs. 10.0%; p<0.05), various menstrual disorders (35.0% vs. 12.5%; p<0.05), including amenorrhea, irregular menstrual cycle and luteal phase insufficiency, high prevalence of genitourinary infections (37.5% vs. 17.5%; p<0.05). Against these disorders background, patients with "long-COVID" have significantly inferior results of in vitro fertilization programs: one in five has "poor ovarian response" (21.3% vs. 2.5%; p<0.05). Clinical pregnancy was diagnosed in 22.5% of patients versus 40.0% (p<0.05), and 2 women had a pregnancy loss in the 1st trimester, while all 16 women in the comparison group carried fetuses to live birth, i.e., the live birth rate was 20.0% versus 40.0% (p<0.05). Conclusions. Determined changes in reproductive function may be directly or indirectly related to the "long-COVID" consequences, namely, a high level of stress, anxiety and depression, pernicious habits, general fatigability that leads to a sedentary lifestyle, sleep disturbances, the developing or exacerbation of somatic pathologies, among which stand out metabolic disorders and pathology of the liver and gastrointestinal tract. This study was conducted in accordance with the principles of the Declaration of Helsinki. The research protocol was approved by the Local Ethics Committee of the abovementioned institution. Informed consents of the women were obtained for participation in this study. The author declares no conflicts of interest

Structural characterisation of tin fluorophosphate glasses doped with Er2O3

EXAFS and confocal Raman microscopy have been used to study 50SnF2.(20-x)SnO.30P2O5.xEr2O3 (x=0, 0.1, 0.25) glasses. EXAFS data reveal an average coordination of Sn to O of 1.5 in both undoped glass and Er-doped glass samples. The first coordination sphere of Er in glasses doped with Er2O3 was found to have 9 F atom neighbours at an average bond length of 2.292+/-0.005 {\AA}, indicating that Er preferentially bonds with F. Raman spectra clearly show the emergence of orthophosphate Q0 units on addition of Er2O3. The saturation of Er solubility is found to be between 0.25 and 0.5 mol$\%$ Er2O3. An increase of the glass transition temperature from $\sim$80{\deg}C in undoped glass to $\sim$87{\deg}C in samples doped with 0.25 mol$\%$ Er2O3 was also observed. This process is accompanied by an increase in the difference between the crystallisation and glass transition temperatures, which is usually associated with improved thermal stability of the glass

Risk factors for the ineffectiveness of assisted reproductive technology programs after a woman’s illness with COVID-19

Purpose - to determine the risk factors for the ineffectiveness of ART programs after a woman’s illness with COVID-19. Materials and methods. In the group of 80 examined patients with symptoms of “long-COVID” who applied to the reproductive technology clinic for infertility treatment, 2 subgroups were distinguished: the Subgroup 1: 64 patients in whom assisted reproductive technologies (ART) was unsuccessful (cancellation of transfer, non-occurrence of pregnancy or its loss) and the Subgroup 2: 16 women with successful ART (live birth). Results. Significant differences were found among patients with unsuccessful use of ART in terms of the frequency of the main symptoms of “long-COVID”, the following symptoms stand out: “depression, anxiety” (54.7% vs. 18.8%, p<0.05) and “sleep disturbances” (59.4% vs. 31.3%, p<0.05). A significant difference was also found in social and household factors: the presence of stress (35.9% vs. 12.5%, p<0.05), especially in everyday life (31.3% vs. 6.3%, p<0.05), the presence of bad habits (21.9% vs. 6.3%, p<0.05). A significantly higher frequency of decreased ovarian reserve (32.8% vs. 12.5%, p<0.05) and corresponding hormonal disorders: increased follicle-stimulating hormone (21.9% vs. 6.3%, p<0.05) and decreased anti-Müllerian hormone (25.0% vs. 6.3%, p<0.05). Among somatic pathology, endocrine pathology stands out (45.3% vs. 12.5%, p<0.05), in particular metabolic disorders (34.4% vs. 12.5%, p<0.05). A significant difference was also established in the frequency of liver diseases (21.9% vs. 6.3%, p<0.05) and gastrointestinal tract (23.4% vs. 12.5%, p<0.05). There is a higher frequency of menstrual disorders, namely a decrease in the duration of menstruation (20.3% vs. 6.3%) or, conversely, prolonged menstruation (17.2% vs. 6.3%), an irregular cycle (25.0% vs. 6.3%, p<0.05) and luteal phase insufficiency (21.9% vs. 6.3%, p<0.05). Urogenital infections were noted in 43.8% of patients (vs. 12.5%, p<0.05). Conclusions. Risk factors for the ineffectiveness of ART programs have been established, among which stress, depression and anxiety, bad habits, endocrine pathology, metabolic disorders, liver pathology, menstrual cycle disorders, and urogenital infections are especially highlighted. The research was carried out in accordance with the principles of the Declaration of Helsinki. The research protocol was approved by the Local Ethics Committee of the institution mentioned in the work. Informed consent of the women was obtained for the research. No conflict of interests was declared by the authors

The influence of neurovegetative and psychological characteristics of infertile patients with long-term COVID-19 on the effectiveness of assisted reproductive technologies

The connection of the long-COVID-19 symptom with violations of various systemic factors, in particular with the female reproductive system, is considered, but the number of such studies is not large. The purpose of the study is the influence of neurovegetative and psychological characteristics of infertile patients with long-term COVID-19 on the effectiveness of assisted reproductive technologies (ART). Materials and methods. The main group consisted of 80 women with infertility and "long-COVID", the comparison group - 40 patients without a history of COVID-19. In the main group, 2 subgroups were distinguished: 1 - 64 women with unsuccessful ART and 2 - 16 patients in whom ART was successful (a live birth was obtained). Socio-economic status and stress factors (questionnaire), fear of stress-19 (FCV-19S scale), autonomic dysfunction were assessed using the O.M. questionnaire. Wayne (1998), Anxiety and Depression Levels on the Hospital Anxiety and Depression Scale (HADS). The used methods of variational statistics using the Student's t-test and Fisher's angular transformation with a critical significance level of p<0.05 were used to calculate the odds ratio (OR) and its confidence interval (CI). Results. Women with infertility and "long-COVID-19" are characterized by a relatively low level of socio-economic status: a lower level of income, a smaller share of entrepreneurs and housewives, not comfortable enough living conditions. These patients have a higher level of stressogenic load: comorbidity with chronic somatic pathology (58.8%), conflict situations in the family (31.3%), dissatisfaction with their sexual relationships (58.7%), a significantly higher level of fear of COVID -19 (29.73±1.31 points). Vegetative dysfunction is diagnosed in 82.5% of patients. Symptoms that are typical for "long-COVID-19" are most often noted: reduced work capacity/fatigue (82.5%), attack-like headaches (72.5%), difficulty breathing (47.5%), sleep disturbances (47 .5%). Unfavorable medico-social and psychological risk factors for the failure of ART programs in patients with "long-COVID-19" can be a point assessment of the autonomic dysfunction syndrome above 25 (OR=5.80, CI 1.22-27.64), anxiety (OR=5.80, CI 1.56-21.62), presence of depression (OR=4.20, CI 1.27-13.89), chronic somatic disease (OR=4.20, CI 1.30-13.62), conflict situations (OR=3.86, CI 1.24-12.04). Conclusions. Women with infertility and "long-COVID-19" need additional examinations to assess the medical and social status, vegetative function and psychological state, correction of detected violations. The research was carried out in accordance with the principles of the Declaration of Helsinki. The research protocol was approved by the Local Ethics Committee of the institution mentioned in the work. Informed consent of the women was obtained for the research. No conflict of interests was declared by the authors

Genetic-epigenetic aspects of infertility in women with long-COVID-19

The aim of the study is to determine the genetic and epigenetic features of infertile patients with long-term COVID-19 in order to clarify the risk factors for the failure of assisted reproductive technologies (ART) use. Materials and methods. The MTHFR (C677T, A1298С), RFC-1 (G80A) and BHMT (G742A) gene polymorphisms and the methylation of ESR1 gene was performed. 40 patients (main group) with infertility due to long-term COVID-19 were examined: the subgroup 1 - 25 women in whom the use of ART was ineffective, the subgroup 2 - 15 patients with effective use of ART. The control was taken from literary sources: for RFC (G80A), MTHFR (C677T) and MTHFR (A1298C) polymorphisms - 35 Ukrainian women without infertility and reproductive losses; for BHMT (G742A) - 60 people of the Ukrainian population. The methods of variational statistics were used, in particular the Fisher test with a significance level of p<0.05. Results. Patients of the main group have a higher frequency of the homozygous genotype of the MTHFR gene polymorphism (C677T) on the mutant T allele (20.0% vs. 3.2%; p<0.05). When ART is unsuccessful, the TT genotype is 4 times greater (28.0% vs. 6.7%; p<0.05). A study by genotypes of MTHFR polymorphism (A1298C) did not reveal a significant difference. Patients of the main group `have a higher frequency of the mutant allele A of the RFC gene (G80A) (80.0% vs. 51.4%; p<0.05). No significant difference was found depending on the success rate of ART. The frequency of BHMT gene polymorphism (G742A) in the main group did not differ from that in the Ukrainian population, however, in the case of unsuccessful ART, it was observed less often and only in the heterozygous variant (40.0% vs. 66.6%; p<0.05). The analysis of pairwise intergenic interaction revealed the highest frequency of the combination of AAGA for the MTHFR (A1298C)+BHMT (G742A) pair - 35.0% and GAAA for the RFC (G80A)+MTHFR (A1298C) pair - 30.0% in the main group. Hypermethylation of the promoter region of the ESR1 gene is observed in 20 (50.0%) patients of the main group: in 17 (68.0%) women of the subgroup 1 versus 3 (20.0%) women of the subgroup 2 (p<0.05). Conclusions. The genetic and epigenetic conditioning of the success of ART programs in infertility associated with long-term COVID-19 has been revealed, which opens up new diagnostic and therapeutic opportunities for identifying factors predisposing to unsuccessful ART treatment and increasing the effectiveness of such treatment by correcting disorders of folic acid metabolism, hyperhomocysteinemia and the estrogens receptor apparatus. The research was carried out in accordance with the principles of the Declaration of Helsinki. The research protocol was approved by the Local Ethics Committee of the institution mentioned in the work. Informed consent of the women was obtained for the research. The authors declare no conflict of interest

Amorphous rigidification and cooperativity drop in semi−crystalline plasticized polylactide

Plasticization of amorphous polylactide shifts the glass transition and extends its temperature range of crystallization to lower temperatures. In this work, we focus on how low−temperature crystallization impacts the mobility of the amorphous phase. Plasticizer accumulates in the amorphous phase because it is excluded from the growing crystal. The formation of rigid amorphous fraction is favored by the low crystallization temperature. It reaches values up to 50% in plasticized polylactide. The increase in the content of rigid amorphous fraction coincides with both the increase of free volume quantified by positron annihilation lifetime spectroscopy, and the decrease in the cooperativity length obtained from the temperature fluctuation approach. The drop of cooperativity is interpreted in terms of mobility gradient due to the amorphous rigidification