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2022 ◽  
Vol 12 (2) ◽  
pp. 609
Author(s):  
Octavia Zeleniuc ◽  
Camelia Coșereanu

The growing demand for wood and the continued increase of the raw material price have resulted in companies using more efficient wood resources in wood-based products such as blockboard. These boards are used in the field of interior design, especially. The aim of this research was to evaluate the effect of variable environmental conditions on the physical and mechanical properties of blockboard (BK). Two types of commercial BK were exposed in variable environmental conditions (kitchen, bathroom and climatic chamber) for three months. The BK structures were composed of veneer (V) and high-density fibreboards (HDF) for the face sheets and glued, solid wood, resinous strips for the core. The temperature and relative humidity of the air (RH) ranged from 18 °C to 25 °C and from 25% to 90%, respectively. In the climatic chamber (CC), the dynamics of the parameter variations were different than in the other two exposure climates, being determined by the programmed cyclic changes in RH. The changes observed on physical and mechanical properties were more extreme for the blockboards tested in the CC than in the kitchen (K) and bathroom (Ba). After 3 months of exposure in the CC, the thickness and weight of the boards increased by 1.8 and 1.1 times, respectively, for veneered BK, and by 4.4 and 0.4 times, for BK with HDF faces, compared to values recorded in the kitchen. The panels exposed in the CC exhibited the highest increase in moisture content (MC): 41% for veneered BK and 82% for BK with HDF faces after three months of exposure, followed by those exposed in the bathroom and kitchen. Increases in MC determined decreases of flexural properties and soundness surfaces, more evident for HDF face structures compared to V ones.


Author(s):  
Ю.Ю. Чеботарева ◽  
В.Г. Овсянников ◽  
М.А. Родина ◽  
И.В. Подгорный ◽  
М.Я. Хутиева

Введение. Изучение механизмов развития репродуктивных нарушений в условиях эксперимента на крысах является одним из важных направлений современной патофизиологии. Крыса имеет функционирующий эстральный цикл, трехнедельную гестацию и гемохориальный тип плацентации. На циклических изменениях в яичниках и эпителии влагалища крысы базируется биологическое моделирование эндокринной гинекологической патологии. В настоящее время интерес представляет разработка экспериментальной модели нарушения полового созревания в периоде детства. Нарушение полового созревания может приводить к различным патологическим изменениям в сфере репродуктивного здоровья в будущем, актуальность данной проблемы очевидна. Цель работы - изучение современных аспектов моделирования преждевременного полового созревания у девочек. Методика. Анализ современных отечественных и зарубежных работ, касающихся механизмов преждевременного полового созревания и исследований в области моделирования данной патологии в экспериментах на крысах. Результаты. Преждевременное половое созревание у девочек - нарушение, проявляющееся развитием одного или комплекса признаков половой зрелости до 7 летнего возраста. Детерминация полового развития связана с особенностью генетических и эпигенетических факторов. К последним традиционно относят характер питания, стресс как адаптационную реакцию, интегрированную с активацией гормонопоэза. Фактор питания связан с функционированием гормонов жировой ткани, включая лептин, грелин, эффектами инсулиноподобного фактора роста. В ряде экспериментальных исследований, связанных с воздействием факторов питания, стресса и световой дезадаптации на репродуктивную систему животного, доказано значимое влияние последней на нейромедиаторные системы мозга. Наименее изученными в механизме преждевременного полового созревания остаются вопросы нейроэндокринной регуляции гонадной оси системой KISS/KISS1R. Продолжение изучения ассоциации изменения профиля нейромедиаторов моноаминового ряда и динамики кисспептина в эксперименте на крысах способно расширить представление о механизмах половой дифференцировки мозга и транслировать полученные данные в клиническую практику, связанную с обследованием девочек с преждевременным половым созреванием. Заключение. В связи с малой распространенностью и ограниченностью представлений о патогенезе преждевременного полового созревания, данная проблема требует детального изучения. Необходимо дальнейшее изучение патогенетических основ данной патологии в условиях биологического моделирования на самках крыс раннего возраста. Introduction. Studying pathogenetic mechanisms responsible for development of reproductive disorders in rat models is an important direction of modern pathophysiology. The rat has a functioning estrous cycle, a three-week gestation, and a hemochorial placentation. Biological modeling of endocrine gynecological pathology is based on cyclic changes in the ovaries and in the epithelium of the rat vagina. Currently, the development of an experimental model of puberty disorders in childhood is of interest. Premature puberty can lead to various pathological changes in future reproductive health. The relevance of this problem is obvious. The aim of this work was to study modern aspects of modeling premature puberty in girls. Method. Modern domestic and foreign reviews on the mechanism of premature puberty and studies of modeling this pathology in experiments on rats were analyzed. Results. Premature puberty in girls is a disorder manifested by the development of one or all signs of puberty as early as before the age of 7 yrs. Sexual development is associated with characteristic roles of genetic and epigenetic factors. The latter traditionally include nutrition and stress as an adaptive reaction integrated with the activation of hormone synthesis. The nutrition factor is related with the functioning of adipose tissue hormones, including leptin, ghrelin, and the effects of insulin-like growth factor. A number of experimental studies on rats addressing effects of nutrition, stress, and light maladaptation on the reproductive system have demonstrated its significant effect on brain neurotransmitter systems. Regarding the mechanism of premature puberty, the least studied issue is the neuroendocrine regulation of the gonadal axis by the KISS/KISS1R system. Continuing study of the association between changes in the profile of monoamine neurotransmitters and the dynamics of kisspeptin in experiments on rats can expand understanding of sexual differentiation mechanisms in the brain. The obtained data can be translated into clinical practice for the management of premature puberty in girls. Conclusion. Due to the rare prevalence of premature puberty and insufficient data on its pathogenesis, this problem requires detailed study. It is necessary to further study the mechanism of this pathology by biological modeling on female rats at an early age.


Environments ◽  
2021 ◽  
Vol 8 (12) ◽  
pp. 137
Author(s):  
Peter Brimblecombe ◽  
Meng-Yuan Chu ◽  
Chun-Ho Liu ◽  
Zhi Ning

Busy street canyons can have a large flow of vehicles and reduced air exchange and wind speeds at street level, exposing pedestrians to high pollutant concentrations. The airflow tended to move with vehicles along the canyon and the 1-s concentrations of NO, NO2 and CO were highly skewed close to the road and more normally distributed at sensors some metres above the road. The pollutants were more autocorrelated at these elevated sensors, suggesting a less variable concentration away from traffic in the areas of low turbulence. The kerbside concentrations also showed cyclic changes approximating nearby traffic signal timing. The cross-correlation between the concentration measurements suggested that the variation moved at vehicle speed along the canyon, but slower vertically. The concentrations of NOx and CO were slightly higher at wind speeds of under a metre per second. The local ozone concentrations had little effect on the proportion of NOx present as NO2. Pedestrians on the roadside would be unlikely to exceed the USEPA hourly guideline value for NO2 of 100 ppb. Across the campaign period, 100 individual minutes exceeded the guidelines, though the effect of short-term, high-concentration exposures is not well understood. Tram stops at the carriageway divider are places where longer exposures to higher levels of traffic-associated pollutants are possible.


2021 ◽  
Vol 576 ◽  
pp. 117232
Author(s):  
Ken-ichi Hirauchi ◽  
Yurina Nagata ◽  
Kengo Kataoka ◽  
Ryosuke Oyanagi ◽  
Atsushi Okamoto ◽  
...  

2021 ◽  
Vol 43 (3) ◽  
pp. 2111-2123
Author(s):  
Yoji Hisamatsu ◽  
Hiromi Murata ◽  
Hiroaki Tsubokura ◽  
Yoshiko Hashimoto ◽  
Masaaki Kitada ◽  
...  

Cyclic changes, such as growth, decidualization, shedding, and regeneration, in the human endometrium are regulated by the reciprocal action of female hormones, such as estradiol (E2), and progesterone (P4). Matrix metalloproteases (MMPs) and tissue inhibitors of MMPs (TIMPs) control the invasion of extravillous trophoblast cells after implantation. Several MMPs and TIMPs function in the decidua and endometrial stromal cells (ESCs). Here, we aimed to systematically investigate the changes in MMPs and TIMPs associated with ESC decidualization. We evaluated the expression of 23 MMPs, four TIMPs, and four anti-sense non-coding RNAs from MMP loci. Primary ESC cultures treated with E2 + medroxyprogesterone acetate (MPA), a potent P4 receptor agonist, showed significant down-regulation of MMP3, MMP10, MMP11, MMP12, MMP20, and MMP27 in decidualized ESCs, as assessed by quantitative reverse transcription PCR. Further, MMP15 and MMP19 were significantly upregulated in decidualized ESCs. siRNA-mediated silencing of Heart and Neural Crest Derivatives Expressed 2 (HAND2), a master transcriptional regulator in ESC decidualization, significantly increased MMP15 expression in untreated human ESCs. These results collectively indicate the importance of MMP15 and MMP19 in ESC decidualization and highlight the role of HAND2 in repressing MMP15 transcription, thereby regulating decidualization.


Vestnik MGSU ◽  
2021 ◽  
pp. 1473-1482
Author(s):  
Irina N. Maksimova ◽  
Irina V. Erofeeva ◽  
Victor V. Afonin ◽  
Denis V. Emelyanov

Introduction. The article addresses the quality evaluation of cement composites after their exposure to the atmospheric environment that features a rapid change in positive and negative temperatures. The article has a numerical assessment of the quality of cement composites. The quality assessment method encompasses the Spearman’s rank correlation, the coefficient of determination, and the adjustment ratio. Materials and methods. Testable cement composites are the compositions numbered from one to eight. They differ in the concentration of various additives, including superplasticizers and aggregates. Testable compositions were exposed to cyclic changes in positive and negative temperatures, and four of their properties were checked in the points of control on Day 0, Day 15, and Day 45. Linear interpolation was used to expand the data array. Changes in the properties of composites were compared with the benchmark values; the Spearman’s rank correlation and the coefficient of determination were calculated. Moreover, arrays of interpolated values were reduced to relative units to calculate the adjustment ratios. Entry values were employed to develop the evaluation metrics and assess the quality of cement composites. Results. The proposed numerical metrics is used to rank the testable samples and identify the best compositions. Library functions and transformations, available in the MATLAB system, are applied to each action, which can be implemented in nearly any software programming language. Conclusions. The proposed method of heuristic quality evaluation of cement composites may be applied to the cases when testable samples are exposed to versatile adverse and aggressive operating conditions.


2021 ◽  
Vol 17 (5) ◽  
pp. 65-79
Author(s):  
G. Sobolova ◽  
M. S. Fabus ◽  
M. Fischer ◽  
M. Drobny ◽  
B. Drobna-Saniova

The human electroencephalogram (EEG) constitutes a nonstationary, nonlinear electrophysiological signal resulting from synchronous firing of neurons in thalamocortical structures of the brain. Due to the complexity of the brain's physiological structures and its rhythmic oscillations, analysis of EEG often utilises spectral analysis methods.Aim: to improve clinical monitoring of neurophysiological signals and to further explain basic principles of functional mechanisms in the brain during anaesthesia.Material and methods. In this paper we used Empirical Mode decomposition (EMD), a novel spectral analysis method especially suited for nonstationary and nonlinear signals. EMD and the related Hilbert-Huang Transform (HHT) decompose signal into constituent Intrinsic Mode Functions (IMFs). In this study we applied EMD to analyse burst-suppression (BS) in the human EEG during induction of general anaesthesia (GA) with propofol. BS is a state characterised by cyclic changes between significant depression of brain activity and hyper-active bursts with variable duration, amplitude, and waveform shape. BS arises after induction into deep general anaesthesia after an intravenous bolus of general anaesthetics. Here we studied the behaviour of BS using the burst-suppression ratio (BSR).Results. Comparing correlations between EEG and IMF BSRs, we determined BSR was driven mainly by alpha activity. BSRs for different spectral components (IMFs 1-4) showed differing rates of return to baseline after the end of BS in EEG, indicating BS might differentially impair neural generators of low-frequency EEG oscillations and thalamocortical functional connectivity.Conclusion. Studying BS using EMD represents a novel form of analysis with the potential to elucidate neurophysiological mechanisms of this state and its impact on post-operative patient prognosis.


2021 ◽  
Vol 55 (s42-s2) ◽  
pp. 223-254
Author(s):  
Maj-Britt Mosegaard Hansen

Abstract The evolution of the negative coordinating conjunction (‘neither’/‘nor’) from Latin to Modern French instantiates a type of cyclic development that is previously undocumented as such at the level of morphosyntax, viz. a ‘semasiological’ cycle. In effect, the conjunction appears to have taken an almost perfectly circular path. Thus, in Classical Latin, as is consonant with the typological status of that language as a Double Negation language, neque/nec was exclusively used in negative contexts. Medieval French being a Negative Concord language, on the other hand, its negative coordinating conjunction, ne, a direct descendant of neque/nec, was able to develop a full range of weak negative polarity uses. In a range of contexts, ne was thus semantically equivalent to either the additive conjunction et (‘and’) or the disjunction ou (‘or’). By the end of the Classical French period, however, the conjunction (which by then takes the form ny/ni) has lost all of its weak negative polarity uses again, and it is used only in strong negatively polar environments in Modern Standard French. Based on data from the electronic corpora Frantext and Base de Français Médiéval, I analyze the three stages of this evolution. I show that, together with other developments in the French negative system, it falsifies predictions made in the literature and has consequences for the reconstruction of negative systems in less well-documented languages.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuji Sano ◽  
Tomoyo Okumura ◽  
Naoko Murakami-Sugihara ◽  
Kentaro Tanaka ◽  
Takanori Kagoshima ◽  
...  

AbstractWe report here hourly variations of Mg/Ca, Sr/Ca, and Ba/Ca ratios in a Mediterranean mussel shell (Mytilus galloprovincialis) collected at the Otsuchi bay, on the Pacific coast of northeastern Japan. This bivalve was living in the intertidal zone, where such organisms are known to form a daily or bidaily growth line comprised of abundant organic matter. Mg/Ca ratios of the inner surface of the outer shell layer, corresponding to the most recent date, show cyclic changes at 25–90 μm intervals, while no interpretable variations are observed in Sr/Ca and Ba/Ca ratios. High Mg/Ca ratios were probably established by (1) cessation of the external supply of Ca and organic layer forming when the shell is closed at low tide, and (2) the strong binding of Mg to the organic layer, but not of Sr and Ba. Immediately following the great tsunami induced by the 2011 Tohoku earthquake, Mg/Ca enrichment occurred, up to 10 times that of normal low tide, while apparent Ba/Ca enrichment was observed for only a few days following the event, therefore serving a proxy of the past tsunami. Following the tsunami, periodic peaks and troughs in Mg/Ca continued, perhaps due to a biological memory effect as an endogenous clock.


2021 ◽  
Vol 42 (Supplement_1) ◽  
Author(s):  
A Ratneswaren ◽  
N Hadjiloizou ◽  
Y Ahmad ◽  
S Sen ◽  
I Maliq ◽  
...  

Abstract Background Left ventricular hypertrophy (LVH) occurs in both aortic stenosis (AS) and hypertension (HT) due to an increase in afterload. However, in AS there is an increase in resting coronary flow (per gram of LV) while in HT it is reduced. Wave intensity analysis (WIA) is a well-established method of characterising and quantifying the energies that drive coronary flow. Energies propagating from the proximal vessel (aorta and systemic arteries) interact with energies travelling from the distal end (myocardial microcirculation). WIA allows the separation of these energies into the waves that drive cyclic changes in coronary flow. Purpose We aimed to compare coronary flow patterns in LVH secondary to AS with coronary flow patterns in LVH secondary to HT. Methods Thirty-one participants were recruited (mean age 63, 18 female), 10 with LVH and severe AS, 11 with LVH and HT, and 10 with no LVH and no AS. Participants underwent invasive pressure and Doppler velocity measurements in each of the left coronary arteries and echocardiography. We applied WIA. Results Mean resting coronary flow per gram of LV tissue (Fig. 1) was increased in participants with LVH secondary to AS (1.62±0.60 ml/min/g) and reduced in participants with LVH secondary to HT (0.49±0.27 ml/min/g), compared to participants with no LVH and no AS (1.47±0.73 ml/min/g). We observed marked differences between the magnitudes of the waves driving coronary flow in the three groups (Fig. 2). Forward and backward travelling waves are shown above and below the line respectively. Waves causing acceleration of coronary forward flow are shown as black and waves causing deceleration are shown in white. Wave 6, the backwards decompression wave (BDW), is particularly important for myocardial perfusion. The BDW corresponds to the diastolic 'suction' of blood down the coronary arteries during myocardial relaxation. The energy of the BDW was increased in LVH secondary to AS (31.1x103 W m–2 s–2) but was reduced in LVH secondary to HT (12.3x103 W m–2 s–2) (p<0.05), compared to participants with no LVH and no AS (14.3x103 W m–2 s–2). The energy of the BDW correlated with LV cavity pressure (r=0.84, p<0.001) and diastolic time (r=−0.62, p<0.001) only in LVH secondary to AS participants. In contrast, the BDW correlated with LV mass (r=−0.49, p=0.03) in participants with LVH secondary to HT and with no LVH and no AS, but not in participants with LVH secondary to AS. Conclusions In hypertension, LVH is associated with reduced mean coronary flow and reduced myocardial “suction” during diastole, presumably by the reduction in myocardial compliance associated with diastolic dysfunction. However, in AS the large pressure gradient between the LV cavity and the aorta results in a large contractile force which is generated in systole and then released in diastole. This large diastolic force overwhelms any local impairment caused by the hypertrophied myocardium and contributes to high resting coronary flow in AS. FUNDunding Acknowledgement Type of funding sources: None.


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