circulation system
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2022 ◽  
Vol 20 (4) ◽  
pp. 62-69
Author(s):  
L. V. Mezentseva ◽  
E. N. Dudnik ◽  
E. V. Nikenina ◽  
M. A. Zapara ◽  
V. G. Samartseva ◽  
...  

Purpose. To study the effect of short-term hypoxic exposure on correlation between microcirculatory parameters (MCR) of symmetric areas of the human head. Materials and methods. MCR parameters of 10 healthy male volunteer were measured by laser Doppler flowmetry method. Short-term hypoxic exposure was produced according to the hypoxic test method using the ReOxy Cardio unit (S. A. Aimediq). We assessed the perfusion metrics left and right areas of interest, neurogenic, myogenic, respiratory and cardiac contributors to vascular tone and correlations between baseline parameters and after hypoxic exposure. Results. We revealed the specificity of regional circulation system rearranging induced by hypoxic load. The specificity is caused by functional asymmetry of correlations between different vascular tone contributors in symmetrical head areas. Strong correlation declining under the hypoxic loads between baseline perfusion on left/right was found. The perfusion changes of symmetrical temporal areas under the hypoxic loads correlate negatively with the baseline perfusion of both the same and the opposite side. Conclusion. Short-term hypoxic load rearranges the balance of different vascular tone contributors regulatory role in MCR of symmetric head areas to maintain the sustainable activity of the whole MRC.


2022 ◽  
Author(s):  
Chenshuo Ma ◽  
Wanlu Li ◽  
Daiwei Li ◽  
Maomao Chen ◽  
Mian Wang ◽  
...  

Abstract Thrombosis in the circulation system can lead to major myocardial infarction and cardiovascular deaths. Understanding thrombosis formation is necessary for developing safe and effective treatments. In this work, using digital light processing (DLP)-based 3D printing, we fabricated sophisticated in vitro models of blood vessels with internal microchannels that can be used for thrombosis studies. In this regard, photoacoustic microscopy (PAM) offers a unique advantage for label-free visualization of the 3D-printed vessel models, with large penetration depth and functional sensitivity. We compared the imaging performances of two PAM implementations: optical-resolution PAM and acoustic-resolution PAM, and investigated 3D printed- vessel structures with different patterns of microchannels. Our results show that PAM can provide clear microchannel structures at depths up to 3.6 mm. We further quantified the blood oxygenation in the 3D-printed vascular models, showing that thrombi had lower oxygenation than the normal blood. We expect that PAM can find broad applications in 3D printing and bioprinting for in vitro studies of various vascular and other diseases.


Atmosphere ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 79
Author(s):  
Tingting Fan ◽  
Yuxing Yang ◽  
Shibin Xu

As a prime circulation system, the western Pacific subtropical high (WPSH) significantly impacts tropical cyclone (TC) activities over the western North Pacific (WNP), especially TCs landing on the east coast of China; however, the associated mechanism is not firmly established. This study investigates the underlying dynamic impact of the first two empirical orthogonal function (EOF) modes of the WPSH on the interannual variability in the genesis and number of TCs landing over the WNP. The results show that these two dominant modes control the WNP TC activity over different subregions via different environmental factors. The first mode (EOF1) affects the TC genesis number over region I (105°–128° E, 5°–30° N) (r = −0.49) and region II (130°–175° E, 17°–30° N) (r = −0.5) and controls the TCs landing on the east coast of China, while the second mode (EOF2) affects the TC genesis number over region III (128°–175° E, 5°–17° N) (r = −0.69). The EOF1 mode, a southwest-northeast-oriented enhanced pattern, causes the WPSH to expand (retreat) along the southwest-northeast direction, which makes both mid-low-level relative humidity and low-level vorticity unfavorable (favorable) for TC genesis in region I and region II and steers fewer (more) TC tracks to land on the coast of China. The EOF2 mode features a strengthened WPSH over the southeast quarter of the WNP region. The active (inactive) phases of this mode control the low-level vorticity and vertical wind shear in region III, which lead to less (more) TC genesis over this region. The prediction equations combining the two modes of the WPSH for the total number of TCs and TCs that make landfall show high correlation coefficients. Our findings verify the high prediction skill of the WPSH on WNP TC activities, provide a new way to predict TCs that will make landfall on the east coast of China, and help to improve the future projection of WNP TC activity.


2021 ◽  
pp. 29-38
Author(s):  
V. A. Osipov ◽  
A. N. Pastukhov ◽  
O. I. Kurbatov ◽  
Yu. P. Potekhina

Introduction. In recent decades, medical science has accumulated convincing evidence of the fact that the normal activity of a human brain depends on the functional integration of its vascular system, a circulation system of cerebrospinal fluid and biomechanical features of a skull, forming a single structural and functional system.The aim of the study is to research the histological structure of functionally significant cranial synchondroses in the middle and elderly age group, to find possible points of osteopathic influence application in their structure. Materials and methods. The study was performed on cadaver material of 27 persons (7 men — 26 %, 20 women — 74 %) who died at the age from 49 to 66 years (57,5±5,3 years) from various somatic pathologies, but had no history of craniocerebral injuries with fractures of osseous structures. Small bone fragments with sutures of interest/synchondroses (spheno-occipital synchondrosis, petro-jugular synchondrosis, sphenopetrosal synchondrosis) were subjected to standard histological processing followed by microscopy.Results. Evaluating histological specimens of spheno-occipital synchondrosis, we observed the similar pattern: highly mineralized tissues at the edges of the bodies of the sphenoid and occipital bones were connected without elements of cartilagi-nous or connective tissue. In all cases, no fibrous or nerve tissue elements were found during the in situ immunohistochemical reactions. Reactions with the CD34 antibody mark multiple vessels of the Volkmann's or Haversian canals. Evaluating histological specimens of petro-jugular and sphenopetrosal synchondroses, we found the presence of cartilage tissue in the suture in the form of small islands of various sizes (from 20 to 120 microns) with signs of degeneration and a small number of remained chondrocytes. When evaluating specimens with immunohistochemical reactions with antibodies against the S100 protein, no elements of the nervous tissue were detected.Conclusion. Spheno-occipital synchondrosis has a temporary nature. With age, its cartilaginous tissue is replaced by osseous one. According to the histological structure, sphenobasilar synchondrosis demonstrates the complete absence of a cartilaginous component in the middle and elderly age groups. Petro-jugular and sphenopetrosal synchondroses retain the cartilaginous component in their suture throughout lifetime. During histological examination of the petro-jugular and sphenopetrosal synchondroses, the cartilaginous component is represented by variety of small islands. In all synchondroses, there is an absence of vascular and nervous components. At the same time, we revealed the presence of a prominent vascular bed in the bone tissue. The fact requires emphasizing the importance of liquid potency and elastic component in cartilaginous and osseous tissues as an application point for osteopathic techniques.


2021 ◽  
Vol 15 (2) ◽  
pp. 131
Author(s):  
Sigit Setyawan ◽  
Ilham Satria Raditya Putra ◽  
Agik Dwika Putra ◽  
Rochim Bakti Cahyono

In power plant industries, boiler feed water (BFW) quality becomes the main parameter for steam generation, which is used for electricity production. To generate standard BFW for power plants, each impurity within water resources should be removed to prevent corrosion and scale deposition by several processes such as sedimentation, coagulation, polishing, and deaeration. Operation conditions that involved high temperature would trigger corrosion as a crucial factor in the maintenance and practical lifetime of the equipment. In the beginning of the operation, PT. Cirebon Electric Power (CEP) used All Volatile Treatment–Reduction (AVT-R) by injection of both ammonia and hydrazine. In order to optimize the operation, the BFW treatment was changed to All Volatile Treatment–Oxidation (AVT-O) that only uses of ammonia and deaerator for removing the dissolved gas. Based on the actual evaluation, AVT technology showed less performance related to corrosion prevention and high chemical consumption. Therefore, PT. CEP tried to implement modification in the BFW treatment, which is AVT technology to Oxygenated Treatment (OT). This paper is to evaluate the effect of those modifications on corrosion prevention and resource-energy saving. The modification into OT showed valuable results that decrease concentration of dissolved Fe from 1 ppb to 0.1 ppb in the deaerator outlet stream. This data reveals that good corrosion prevention can be achieved through the creation of passive layers, hematite Fe2O3. Oxygen injection into the water circulation system yielded an oxidation atmosphere so that the passive layer, Fe2O3, was formed. In addition to corrosion prevention, this modification also cut the amount of ammonia injection into the system from 2 ppm to 0.12 ppm. Reduction of that ammonia injection provides other benefits such as decreasing the volume of resin regeneration, which becomes only twice a month. This situation also created other benefits such as reducing the regeneration water, chemicals, and wastewater. Thus, the modification could establish the electricity production by PT. CEP more environmentally friendly and sustainable.A B S T R A KPada operasi PLTU, kualitas boiler feed water (BFW) menjadi parameter yang krusial untuk menghasilkan steam yang akan digunakan untuk memproduksi listrik. Untuk mendapatkan BFW sesuai dengan standar yang ada, maka pengotor di dalam air baku industri harus dihilangkan karena dapat menyebabkan korosi dan pembentukan kerak, baik pada pipa maupun peralatan. Kondisi operasi yang melibatkan steam pada suhu tinggi menyebabkan korosi menjadi masalah yang krusial terutama terkait dengan maintenance dan umur efektif pabrik. Pada awal berdirinya, PT. Cirebon Electric Power (CEP) menggunakan teknologi All Volatile Treatment–Reduction (AVT-R) dengan injeksi amonia dan hidrazin. Selanjutnya, dilakukan optimasi melalui perubahan proses menjadi All Volatile Treatment–Oxidation (AVT-O) dengan hanya menginjeksikan amonia dan mengoptimalkan fungsi deaerator untuk menghilangkan pengotor dissolved gas. Berdasarkan data lapangan, teknologi AVT yang digunakan kurang memberikan pencegahan korosi yang baik dan juga jumlah bahan kimia yang digunakan masih relatif banyak. Agar lebih ramah lingkungan dan handal, PT. CEP berusaha untuk melakukan modifikasi terhadap pengolahan boiler feed water (BFW) dari yang semula menggunakan teknologi AVT-O menjadi Oxygenated Treatment (OT). Penelitian ini bertujuan untuk mengevaluasi dampak modifikasi sistem AVT menjadi OT pada pencegahan korosi dan juga penghematan sumber daya. Modifikasi sistem AVT-O menjadi OT berhasil menurunkan konsentrasi dissolved Fe dari 1 ppb menjadi 0,1 ppb pada BFW. Hal ini menunjukkan terjadinya peningkatan pencegahan korosi melalui pembentukan double protective layer yang merupakan kombinasi magnetite (Fe3O4) dan hematite (Fe2O3). Injeksi oksigen ke dalam sistem mengubah kondisi air menjadi suasana oksidasi sehingga mampu mengubah dan membentuk lapisan baru sebagai pencegahan korosi. Selain pencegahan korosi, modifikasi ini juga berhasil menurunkan jumlah injeksi amonia dari 2 ppm menjadi 0,12 ppm dalam siklus air yang ada. Penurunan jumlah injeksi amonia ini akan memberikan keuntungan beruntun berupa berkurangnya frekuensi regenerasi resin dari semula 8 menjadi 2 kali perbulan. Kondisi ini akan menghasilkan penghematan sumber daya berupa kebutuhan air untuk regenerasi, bahan kimia amonia, dan beban pencemaran. Oleh karena itu, modifikasi ini telah membuat proses produksi listrik di PT. CEP lebih ramah lingkungan dan berkelanjutan.Kata kunci: All Volatile Treatment (AVT); efisiensi energi; korosi boiler; Oxygenated Treatment (OT)


Author(s):  
Keith A. Potts

Three significant changes have occurred in the winter climate in Europe recently: increased UK flooding; Iberian drought; and warmer temperatures north of the Alps. The literature links all three to a persistent, significant increase in sea level pressure over Southern Europe, the Mediterranean, Iberia and the Eastern Atlantic (SEMIEA) which changes the atmospheric circulation system: forcing cold fronts to the north away from Iberia; and creating a south westerly flow around the northern perimeter of the high-pressure region bringing warmer, moist air from the subtropical Atlantic to the UK and Europe which increases precipitation in the UK and raises the temperature in Europe. I use the Last Millennium Ensemble, MERRA-2 and Terra-NCEP data to demonstrate that the extreme, anthropogenic, West African aerosol Plume (WAP) which only exists from December to April perturbs the northern, regional Hadley Circulation creating the high pressure in the SEMIEA. I also show that the anthropogenic WAP has only existed in its extreme form in recent decades as the two major sources of the WAP aerosols: biomass burning; and gas flaring have both increased significantly since 1950 due to: a four-fold increase in population; and gas flaring rising from zero to 7.4 billion m3/annum and note that this time span coincides with the changes in the three elements of the winter climate of Europe. I also suggest that it may be possible to eliminate the WAP and return the winter climate of Europe to its natural state after the crucial first step of recognising the cause of the changes is taken.


2021 ◽  
Vol 24 (2) ◽  
pp. 169
Author(s):  
Ainul Uyuni Taufiq ◽  
Asniati Jabbar ◽  
Zulkarnaim Zulkarnaim

Abstract:This research aimed to: (1) develop learning media of Panjat Pinang Bio Board Games based on circulation system material for class XI of MA GUPPI Samata, (2) determine the level of validity, practicality, and effectiveness of Panjat Pinang Bio Board Games. The research method employed was Research and Development (R & D) with the 4-D development model, namely define, design, develop, and disseminate. The instruments used were validation sheets, educator and student questionnaires, and questions. The population was 24 students of class XI, and six students were selected as samples. The results indicated that the average validity level was 3.62 with valid category, while the average practicality level was 3.10 with practical category. The level of efficacy was 100% which fulfilled the completeness criteria with effective category. Therefore, Panjat Pinang Bio Board Games was considered practicable to employ since it matched the criteria of being valid, practical, and effective. Selecting appropriate learning media supports students' learning outcomes. Abstrak:Penelitian bertujuan (1) mengembangkan media pembelajaran Bio Board Gamess Panjat Pinang pada materi sistem sirkulasi kelas XI MA pesantren GUPPI Samata, (2) mengetahui tingkat kevalidan, kepraktisan, dan keefektifan media pembelajaran Bio Board Gamess Panjat Pinang pada materi sistem sirkulasi kelas XI MA pesantren GUPPI Samata. Metode penelitian yaitu research and development (R & D) dengan model pengembangan 4-D yaitu define, design, develop dan disseminate. Instrumen penelitian yang digunakan di antaranya lembar validasi, angket respon pendidik dan peserta didik, dan soal. Populasi dalam penelitian ini adalah siswa kelas XI dan terpilih 6 orang sebagai sampel. Hasil penelitian menunjukkan tingkat validitas 3,62 dengan kategori valid, tingkat kepraktisan rata-rata 3,10 dengan kategori praktis. Tingkat keefektifan mencapai 100% yang memenuhi nilai KKM dengan kategori efektif. Sehingga media pembelajaran Bio Board Gamess Panjat Pinang layak digunakan karena memenuhi kriteria valid, praktis dan efektif. Pemilihan media pembelajaran yang tepat mendukung hasil belajar siswa.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Gita Pati Humairoh ◽  
Rama Dani Eka Putra

Indoor air pollution is a very serious health issue in comparison with outdoor air conditions. The current pandemic of COVID-19 causes people to remain indoors at all times. It is unimaginable that during this pandemic a smog-related disaster could occurs that could aggravate human respiratory diseases, thus requires additional air quality monitoring which can filter clean air into the room. The purpose of this study is to produce a prototype of air quality control that can provide a good air circulation system and hold the temperature and humidity in the room. This research was conducted with an Arduino Uno microcontroller and an MQ-135 gas sensor to detect CO2 gas and a DHT-22 sensor for measuring room temperature and humidity by comparing the results of using a HEPA filter. The research results of the prototype make it possible to generate the room temperature using a HEPA filter and air humidifier whose average is 27.7°C. Another parameter that is performed is the CO2 measurement, it is found that the average CO2 in the test using a HEPA filter and an air humidifier is 496 PPM.


Clean Energy ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 841-852
Author(s):  
Hongwei Zhang ◽  
Junqing Liu ◽  
Wenbin Liang ◽  
Hongqing Shan ◽  
Jie Wang

Abstract In view of the continuous increase in the proportion of renewable energy connected to the grid in China and the increasing peak-to-valley difference in electricity demand on the power grid, this paper proposes a high-temperature thermal-storage combined-cycle power-generation system. Using Thermoflex thermal simulation analysis software, a high-temperature thermal-storage combined-cycle simulation analysis system model was established, and the influence of different initial temperatures and pressure ratios on the combined-cycle system was analysed. Sensitivity analysis of factors such as electricity cost, annual operating hours, initial equipment investment, unit efficiency and other factors that affect the net income of the system was carried out. According to the current power-peak-shaving auxiliary service market in China, it is pointed out that high-temperature thermal-storage combined-cycle projects must be profitable and obtain good economic benefits. The results obtained, on the one hand, provide suggestions for the flexibility and transformation of current gas-fired steam generators for peak shaving and, on the other hand, provide references for the subsequent development of high-temperature thermal-storage combined-cycle demonstration projects.


2021 ◽  
Vol 12 ◽  
Author(s):  
Jingxian Liu ◽  
Feng Chen ◽  
Hongyan Guan ◽  
Jiajia Yu ◽  
Jing Yu ◽  
...  

Streptococcus agalactiae [also known as group B Streptococcus (GBS)] is a tremendous threat to young infants. Eighty pediatric GBS infection cases were enrolled from a teaching hospital in Shanghai between 2009 and 2020; among them, 72.5% (58/80) were diagnosed with bloodstream infection (BSI). Sequence types (STs) and serotypes of associated GBS strains were identified, and most of the Ib/clonal complex (CC)12 (86.7%, 13/15) strains caused BSIs, which was significantly higher than that of the genetically related clone Ib/CC10 (20%, 2/10; p < 0.05). Ib/CC12 BSI (30.8%) mortality was significantly higher than that of non-Ib/CC12 BSI (2.2%; p < 0.05). Virulence genes associated with adhesion, invasion, and immune evasion were detected using polymerase chain reaction. The fbsA and gbsPC1 positive rates of Ib/CC12 strains was higher than that of non-Ib/CC12 strains, whereas cpsIaJ, cpsJ, cpsI, and cpsG positive rates were lower than those of non-Ib/CC12 (p < 0.05). In in vitro studies, the Ib/CC12 strains had strong invasiveness in RAW264.7 cells, but less invasiveness in human umbilical vein endothelial cells, human brain microvascular endothelial cells, and human mammary epithelial cells when compared to other two clones. In the in vivo model, the Ib/CC12 GBS invaded the circulation system more rapidly after intraperitoneal injection, was more difficult to eradicate by phagocytes, and caused significantly higher mortality than Ib/CC10 and III/ST17 (p < 0.05). Genome analysis showed that the Ib/CC12 strains had two clustered regularly interspaced short palindromic repeat-Cas systems and carried more antibiotic resistant genes, which conferred resistance to macrolides, clindamycin, aminoglycosides, and tetracycline. The Ib/CC12 strains had 45 unique annotated genes compared to that of Ib/CC10, including the pathogen-related toxin/antitoxin system, PezA/T. In conclusion, Ib/CC12 is an emerging hypervirulent multiresistant GBS clone that causes invasive and fatal infections in pediatric patients. The prevention and control of Ib/CC12 GBS infection should be emphasized.


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