bluuebunny/crossref_metadata_2025 huggingface dataset:
A Dynamic Model for Indoor Temperature Prediction in Buildings
Authors: Hietaharju Petri , Ruusunen Mika , Leiviskä Kauko
Published: June 2018

A novel dynamic model for the temperature inside buildings is presented, aiming to improve energy efficiency by providing predictive information on the heat demand. To analyse the performance and generalizability of the modelling approach, real measurement data was gathered from five different types of buildings. Easily available data from various sources was utilized. The chosen model structure leads to a minimal number of input variables and free parameters. Simulations with real data from five buildings, and applying the identical model structure showed that the average modelling error during the 28-h prediction horizon was constantly below 5%. The results thus demonstrate that the model structure can be standardized and easily applied to predict the indoor temperatures of large buildings. This would finally enable demand side management and the predictive optimization of the heat demand at city level.
Decoupling Greenhouse Gas Emissions from Crop Production: A Case Study in the Heilongjiang Land Reclamation Area, China
Authors: Zhang Yu , Zou Xiaojiao , Xu Caifen , Yang Qingshan
Published: June 2018

Modern agriculture contributes significantly to greenhouse gas emissions in several ways. From the perspective of sustainability assessment, it is not enough to evaluate mitigation measures that rely only on emissions reductions. In this article, we use the method of decoupling analysis to construct a decoupling index based on carbon footprint and crop yield and evaluate the relationship between crop production and greenhouse gas emissions using the most modern grain production base in China as a case study. The results indicate that a weak but variable decoupling trend occurred from 2001 to 2015 and that each branch achieved on average a weak decoupling across the study period. In addition, rice production constituted 80% of the regional carbon footprint in a crop’s life cycle. The results of our analysis of rice production show that weak decoupling was the most common outcome but was not consistent because a weak coupling occurred in 2015. Each branch on average achieved a weak decoupling except for the SH branch. Our research indicates that high agricultural material inputs with low utilization efficiency contributed to the poor relationship between crop production and greenhouse gas emissions in the study area. Fertilizer, especially N fertilizer, was an important contributor to the total greenhouse gas emissions of crop production. As a supplement to carbon footprint assessment, this decoupling analysis helps local decision-makers diagnose the level of green growth, identify key options to mitigate greenhouse gas emissions from agriculture, and adopt more targeted interventions towards sustainable agriculture.
An Efficient Controlled Islanding Strategy for Large-Scale AC/DC Power Systems
Authors: Song Changcheng , Chu Xiaodong , Ma Linlin , Wang Xiaobo , Li Xin , Wang Liang , Zhang Bing , Wu Cheng
Published: June 2018

A controlled islanding strategy should be carefully designed to prevent power systems from overall collapse caused by extremely serious faults, which is of high computational complexity for large-scale AC/DC power systems. An efficient controlled islanding strategy for large-scale AC/DC power systems is proposed in this paper. The original power system is first reduced to decrease the computational complexity. The reduced power system is then partitioned into a number of dispatch areas by using the breadth-first search algorithm. Next, the reduced power system is recovered to obtain the detailed information of the dispatch areas. The spectral clustering algorithm is used to cluster the large number of dispatch areas into a small number of islanding areas. Finally, the controlled islanding strategy is verified by assessing the steady and dynamic performance of the power system. The feasibility, efficacy, and adaptability of the controlled islanding strategy are demonstrated by the case study of a large-scale multi-infeed AC/DC power system in China.
Microbial Taxa and Soil Organic Carbon Accumulation Driven by Tree Roots
Authors: Song Wenchen , Liu Yanhong
Published: June 2018

Rhizosphere microbes in forests are key elements for carbon accumulation in terrestrial ecosystems. To date, little is known on the rhizomicrobial community changes occurring during soil carbon accumulation. Using high-throughput DNA sequencing, we identified the phyla composing the rhizomicrobial communities of Pinus tabuliformis Carr. and Quercus variabilis Blume forests in North China and their abundance. These results were correlated with the soil organic carbon (SOC) accumulation driven by tree roots. Rhizomicrobial community composition and abundance and SOC accumulation varied with tree species, but root presence benefited SOC accumulation significantly. Different phyla played different roles in root-driven carbon accumulation during the succession of a recovery forest ecosystem, but Proteobacteria and Basidiomycota were keystones for root-driven carbon accumulation.
In silico Phylogenetic Analysis of hAT Transposable Elements in Plants
Authors: Karakülah Gökhan , Pavlopoulou Athanasia
Published: June 2018

Transposable elements of the hAT family exhibit a cross-kingdom distribution. The plant hAT transposons are proposed to play a critical role in plant adaptive evolution and DNA damage repair. The sequencing of an increasing number of plant genomes has facilitated the discovery of a plethora of hAT elements. This enabled us to perform an in-depth phylogenetic analysis of consensus hAT sequences in the fully-sequenced genomes of 11 plant species that represent diverse taxonomic divisions. Four putative nucleotide sequences were detected in cottonwood that were similar to the corresponding animal hAT elements, which are possibly sequence artifacts. Phylogenetic trees were constructed based both on the known and putative hAT sequences, by employing two different methods of phylogenetic inference. On the basis of the reconstructed phylogeny, plant hAT elements have rather evolved through kingdom-specific vertical gene transfer and gene amplifications within eudicotyledons, monocotyledons, and chlorophytes. Furthermore, the plant hAT sequences were searched for conserved DNA and amino acid sequence features. In this way, diagnostic sequence patterns were detected which allowed us to assign functional annotations to the plant hAT sequences.
Impacts of Urban Sprawl on Soil Resources in the Changchun–Jilin Economic Zone, China, 2000–2015
Authors: Li Xiaoyan , Yang Limin , Ren Yongxing , Li Huiying , Wang Zongming
Published: June 2018

The Changchun–Jilin Economic Zone (CJEZ) is one of the most rapidly developing areas in Northeast China, as well as one of the famous golden maize belts in the world. This is a case study to assess the impacts of urban sprawl on soil resources using remote sensing imagery and geographic spatial analysis methods. The common urbanization intensity index (CUII), soil quality index, and soil landscape metrics were calculated to reflect urbanization and the response of soil resource. Results showed that the area of soil sealing changed from 112,460 ha in 2000 to 139,233 ha in 2015, and in the rural region, the area occupied by urbanization nearly kept balance with the area of rural residential expansion. Urban land increased by 26,767 ha at an annual rate of 3.23% from 2000 to 2015. All seven soil types were occupied during the urbanization process, among which black soil ranked the highest (18,560 ha) and accounted for 69.34% of the total occupied area. Soils of Grades I (3927 ha) and II (15,016 ha) were 64.75% of the total occupied soil areas. Urban land expanded in an irregular shape and a disordered way, which led to an increasing large patch index (LPI) and aggregation index (AI), and a decreasing edge density (ED) and Shannon’s diversity index (SHDI) of the soil landscape in the study area during 2000–2015. According to the geographically weighted regression (GWR) model analysis, the R2 between the CUII and soil landscape metrics decreased from the LPI and ED to SHDI and in turn to AI. The local R2 between SHDI, ED, and CUII showed a gradient structure from the inner city to peri-urban areas, in which larger values appeared with strongly intensive urbanization in urban fringes. Soil sealing induced by urbanization has become a significant factor threatening soil, the environment, and food security. How to coordinate regional development and ensure the sustainability of the multiple functions of soil is a problem that needs to be taken into account in the future development of the region.
Perception of Physical Fitness and Exercise Self-Efficacy and Its Contribution to the Relationship between Body Dissatisfaction and Physical Fitness in Female Minority Children
Authors: Flanagan Emily W. , Perry Arlette C.
Published: June 2018

Body Dissatisfaction (BD) and low physical self-concept and exercise efficacy have been linked to poor physical fitness levels and adverse health outcomes in children. The purpose of this study was to examine the relationship between BD, physical fitness, exercise self-efficacy, and self-Perception of Physical Fitness (PFP) in Latina and Black female children. Twenty-eight Latina and Black children enrolled in an elementary afterschool program, aged 8–12, completed surveys evaluating body dissatisfaction, exercise efficacy, PFP, and measures of physical fitness. Subjects exhibited moderate but significant inverse relationships between BD and PFP in strength (r = −0.459), agility (r = −0.382), aerobic fitness (r = −0.354), and flexibility (r = −0.461) (p < 0.05 for all). There was a significant negative correlation between exercise efficacy and BD (r = −4.2; p < 0.05). Power (r = 0.51) and flexibility (r = 0.42) were the only physical fitness measures significantly and positively related to children’s PFP (p < 0.05). A significant medium inverse relationship was also found between BD and aerobic fitness scores (r = −0.381; p < 0.05). However, after controlling for exercise efficacy or perception of physical fitness, the relationship between BD and aerobic fitness was not significant (p > 0.05). Findings suggest that positive PFP and positive performance in several physical fitness measures are associated with lower levels of BD in minority female children. Furthermore, evidence suggests exercise efficacy and PFP can mediate the relationship body image and aerobic fitness. These findings suggest that PFP, more so than measured physical fitness, was associated with lower levels of BD in minority female children. These results have important implications for programs designed to improve physical fitness and mental health in minority children.
Use of Facebook by Hospitals in Taiwan: A Nationwide Survey
Authors: Yang Po-Chin , Lee Wui-Chiang , Liu Hao-Yen , Shih Mei-Ju , Chen Tzeng-Ji , Chou Li-Fang , Hwang Shinn-Jang
Published: June 2018

Background: Social media advertising has become increasingly influential in recent years. Because Facebook has the most active users worldwide, many hospitals in Taiwan have created official Facebook fan pages. Our study was to present an overview of official Facebook fan pages of hospitals in Taiwan. Methods: All 417 hospitals were surveyed about their use of Facebook fan pages in December 2017. The last update time, posts in the past 30 days, number of “Likes”, and other features were analyzed and stratified according to the accreditation statuses of the hospitals. Results: In Taiwan, only 51.1% (n = 213) of the hospitals had an official Facebook fan page. Among these hospitals, 71.8% (n = 153) had updated their pages in the past 30 days, although 89.2% (n = 190) provided online interactions. Academic medical centers tended to have more “Likes” than regional and local community hospitals (on average 5947.4, 2644.8, and 1548.0, respectively). Conclusions: In spite of the popularity of Facebook among the general population, most hospitals in Taiwan do not seem to make good use of this kind of social media. The reasons for the use and nonuse of Facebook on the part of both hospitals and patients deserve further investigation.
A Muscarinic Antagonist Reduces Airway Inflammation and Bronchoconstriction Induced by Ambient Particulate Matter in a Mouse Model of Asthma
Authors: Kurai Jun , Watanabe Masanari , Sano Hiroyuki , Iwata Kyoko , Hantan Degejirihu , Shimizu Eiji
Published: June 2018

Ambient particulate matter (PM) can increase airway inflammation and induce bronchoconstriction in asthma. This study aimed to investigate the effect of tiotropium bromide, a long-acting muscarinic antagonist, on airway inflammation and bronchoconstriction induced by ambient PM in a mouse model of asthma. We compared the effect of tiotropium bromide to that of fluticasone propionate and formoterol fumarate. BALB/c mice were sensitized to ovalbumin (OVA) via the airways and then administered tiotropium bromide, fluticasone propionate, or formoterol fumarate. Mice were also sensitized to ambient PM via intranasal instillation. Differential leukocyte counts and the concentrations of interferon (IFN)-γ, interleukin (IL)-5, IL-6, IL-13, and keratinocyte-derived chemokine (KC/CXCL1) were measured in bronchoalveolar lavage fluid (BALF). Diacron-reactive oxygen metabolites (dROMs) were measured in the serum. Airway resistance and airway inflammation were evaluated in lung tissue 24 h after the OVA challenge. Ambient PM markedly increased neutrophilic airway inflammation in mice with OVA-induced asthma. Tiotropium bromide improved bronchoconstriction, and reduced neutrophil numbers, decreased the concentrations of IL-5, IL-6, IL-13, and KC/CXCL1 in BALF. However, tiotropium bromide did not decrease the levels of dROMs increased by ambient PM. Though eosinophilic airway inflammation was reduced with fluticasone propionate, neutrophilic airway inflammation was unaffected. Bronchoconstriction was improved with formoterol fumarate, but not with fluticasone propionate. In conclusion, tiotropium bromide reduced bronchoconstriction, subsequently leading to reduced neutrophilic airway inflammation induced by ambient PM.
Influence of Bacterial Biofilm Polysaccharide Structure on Interactions with Antimicrobial Peptides: A Study on Klebsiella pneumoniae
Authors: Bellich Barbara , Lagatolla Cristina , Tossi Alessandro , Benincasa Monica , Cescutti Paola , Rizzo Roberto
Published: June 2018

Biofilms are complex systems produced by bacteria and constituted by macromolecular matrix embedding cells. They provide advantages to bacteria including protection against antimicrobials. The protection given by biofilms produced by Klebsiella pneumoniae strains towards antimicrobial peptides of the innate immune system was investigated. In particular, the role of matrix bacterial exopolysaccharides was explored. Three clinical strains producing exopolysaccharides with different chemistry were selected and the interaction of purified biofilm polysaccharides with two bovine cathelicidins was studied by circular dichroism spectroscopy and microbiological assays to establish their influence on the peptide’s antimicrobial activity. The spectroscopic data indicated a different extent of interaction with the two peptides, in a manner dependent on their sugar composition, and in particular the presence of rhamnose residues correlated with a lower interaction. The extent of interaction was then related to the protection towards antimicrobial peptides, conferred by the addition of the different exopolysaccharides, in minimum inhibitory concentration (MIC) assays against a reference Escherichia coli strain. Microbiological results were in very good agreement with spectroscopic data, confirming the active role of matrix polysaccharides in determining a biofilm’s protective capacity and indicating lower protection levels afforded by rhamnose containing exopolysaccharides.
Physiological and Proteomics Analyses Reveal Low-Phosphorus Stress Affected the Regulation of Photosynthesis in Soybean
Authors: Chu Shanshan , Li Hongyan , Zhang Xiangqian , Yu Kaiye , Chao Maoni , Han Suoyi , Zhang Dan
Published: June 2018

Previous studies have revealed a significant genetic relationship between phosphorus (P)-efficiency and photosynthesis-related traits in soybean. In this study, we used proteome profiling in combination with expression analysis, biochemical investigations, and leaf ultrastructural analysis to identify the underlying physiological and molecular responses. The expression analysis and ultrastructural analysis showed that the photosynthesis key genes were decreased at transcript levels and the leaf mesophyll and chloroplast were severely damaged after low-P stress. Approximately 55 protein spots showed changes under low-P condition by mass spectrometry, of which 17 were involved in various photosynthetic processes. Further analysis revealed the depression of photosynthesis caused by low-P stress mainly involves the regulation of leaf structure, adenosine triphosphate (ATP) synthesis, absorption and transportation of CO2, photosynthetic electron transport, production of assimilatory power, and levels of enzymes related to the Calvin cycle. In summary, our findings indicated that the existence of a stringent relationship between P supply and the genomic control of photosynthesis in soybean. As an important strategy to protect soybean photosynthesis, P could maintain the stability of cell structure, up-regulate the enzymes’ activities, recover the process of photosystem II (PSII), and induce the expression of low-P responsive genes and proteins.
Impact Toughness of Subzones in the Intercritical Heat-Affected Zone of Low-Carbon Bainitic Steel
Authors: Li Zhenshun , Zhao Xuemin , Shan Dongri
Published: June 2018

The subzones of the intercritical heat-affected zone (IC HAZ) of low-carbon bainitic steel were simulated by using a Gleeble-3500 simulator to study the impact toughness. The results showed that the IC HAZ is not entirely brittle and can be further divided into three subzones according to the impact toughness or peak welding temperature; the invariant subzone heated between the critical transformation start temperature (Ac1) and 770 °C exhibited unchanged high impact toughness. Furthermore, an extremely low impact toughness was found in the embrittlement subzone, heated between 770 and 830 °C, and the reduction subzone heated between 830 °C and the critical transformation finish temperature (Ac3) exhibited toughness below that of the original metal. The size of the blocky martensite-austenite (M-A) constituents was found to have a remarkable level of influence on the impact toughness when heated below 830 °C. Additionally, it was found that, once the constituent size exceeds a critical value of 3.0 µm at a peak temperature of 770 °C, the IC HAZ becomes brittle regardless of lath or twinned martensite constitution in the M-A constituent. Essentially, embrittlement was observed to occur when the resolved length of initial cracks (in the direction of the overall fracture) formed as a result of the debonding of M-A constituents exceeding the critical Griffith size. Furthermore, when the heating temperature exceeded 830 °C, the M-A constituents formed a slender shape, and the impact toughness increased as the area fraction of the slender M-A constituents decreased.
Copper-Doped Bioactive Glass as Filler for PMMA-Based Bone Cements: Morphological, Mechanical, Reactivity, and Preliminary Antibacterial Characterization
Authors: Miola Marta , Cochis Andrea , Kumar Ajay , Arciola Carla Renata , Rimondini Lia , Verné Enrica
Published: June 2018

To promote osteointegration and simultaneously limit bacterial contamination without using antibiotics, we designed innovative composite cements containing copper (Cu)-doped bioactive glass powders. Cu-doped glass powders were produced by a melt and quenching process, followed by an ion-exchange process in a Cu salt aqueous solution. Cu-doped glass was incorporated into commercial polymethyl methacrylate (PMMA)-based cements with different viscosities. The realized composites were characterized in terms of morphology, composition, leaching ability, bioactivity, mechanical, and antibacterial properties. Glass powders appeared well distributed and exposed on the PMMA surface. Composite cements showed good bioactivity, evidencing hydroxyapatite precipitation on the sample surfaces after seven days of immersion in simulated body fluid. The leaching test demonstrated that composite cements released a significant amount of copper, with a noticeable antibacterial effect toward Staphylococcus epidermidis strain. Thus, the proposed materials represent an innovative and multifunctional tool for orthopedic prostheses fixation, temporary prostheses, and spinal surgery.
Fast-Response and Reusable Oxytetracycline Colorimetric Strips Based on Nickel (II) Ions Immobilized Carboxymethylcellulose/Polyacrylonitrile Nanofibrous Membranes
Authors: Abedalwafa Mohammed Awad , Li Yan , Li De , Lv Xiaojun , Wang Lu
Published: June 2018

Driven by economic interests, the abuse of antibiotics has become a significant concern for humans worldwide. As one of the most commonly used antibiotics, oxytetracycline (OTC) residue in animal-derived foods occurs occasionally, which has caused danger to humanity. However, there is still no simple and efficient solution to detect OTC residue. Here, an easily-operated colorimetric strategy for OTC detection was developed based on nickel ions (Ni2+) immobilized carboxymethylcellulose/polyacrylonitrile nanofibrous membranes (Ni@CMC/PAN NFMs). Owing to numerous O- and N-containing groups OTC has a strong tendency to complex with Ni2+ on the strips, inducing a color change from light green to yellow visible to the naked eye. The NFMs structural features, CMC functionalization process, and Ni2+ immobilization amount was carefully regulated to assure OTC detection whilst maintaining the inherent characteristics of NFMs. With the benefits of the large specific surface area (SSA) and small pore size of NFMs, the strips not only exhibited a rapid response (2 min), and low detection limit (5 nM) but also performed with good reversibility and selectivity concerning OTC detection over other antibiotics. The successful development of such enchanting nanofibrous materials may provide a new comprehension into the design and improvement of colorimetric strips.
Plasmon-Induced Transparency Based on Triple Arc-Ring Resonators
Authors: Dong Guang-Xi , Xie Qin , Zhang Qi , Wang Ben-Xin , Huang Wei-Qing
Published: June 2018

This paper presents a plasmon-induced transparency (PIT) using an easy-fabricating metamaterial composed of three pieces of metallic arc-rings on top of a dielectric substrate. The transmission of the transparent peak of 1.32 THz reaches approximately 93%. The utilization of the coupled Lorentzian oscillator model and the distribution of electromagnetic fields together explain the cause of the transparent peak. The simulation results further demonstrate that the bandwidth of the transmission peak can be narrowed by changing the sizes of the arc-rings. Moreover, an on/off effect based on the transparent peak is discussed by introducing photosensitive silicon into the air gaps of the suggested metamaterial structure.
Diversity and properties of connexin gap junction channels
Authors: Račkauskas Mindaugas , Neverauskas Vaidas , Skeberdis Vytenis
Published: June 2018

Gap junction channels are composed of two apposing hemichannels (connexons) in the contiguous cells and provide a direct pathway for electrical and metabolic signaling between adjacent cells. The family of connexin genes comprises 20 members in the mouse and 21 genes in the human genome. Connexins are expressed in all tissues except differentiated skeletal muscle, erythrocytes, and mature sperm cells. Various tissues express more than one type of connexins; therefore, homotypic, heterotypic, and heteromeric gap junction channels may form between cells. In this article, we briefly review basic gating and permeability properties of homotypic and heterotypic gap junction channels as well as recent achievements in the research of their regulation by transjunctional voltage, intracellular calcium, pH, and phosphorylation.
Radiofrequency ablation of liver tumors (I): biological background
Authors: Vanagas Tomas , Gulbinas Antanas , Pundzius Juozas , Barauskas Giedrius
Published: June 2018

Majority of patients suffering from liver tumors are not candidates for surgery. Currently, minimal invasive techniques have become available for local destruction of hepatic tumors. Radiofrequency ablation is based on biological response to tissue hyperthermia. The aim of this article is to review available biological data on tissue destruction mechanisms. Experimental evidence shows that tissue injury following thermal ablation occurs in two distinct phases. The initial phase is direct injury, which is determined by energy applied, tumor biology, and tumor microenvironment. The temperature varies along the ablation zone and this is reflected by different morphological changes in affected tissues. The local hyperthermia alters metabolism, exacerbates tissue hypoxia, and increases thermosensitivity. The second phase – indirect injury – is observed after the cessation of heat stimulus. This phase represents a balance of several promoting and inhibiting mechanisms, such as induction of apoptosis, heat shock proteins, Kupffer cell activation, stimulation of the immune response, release of cytokines, and ischemia-reperfusion injury. A deeper understanding of the underlying mechanisms may possibly lead to refinements in radiofrequency ablation technology, resulting in advanced local tumor control and prolonged overall survival.
The influence of thoracic epidural anesthesia on liver hemodynamics in patients under general anesthesia
Authors: Trepenaitis Darius , Pundzius Juozas , Macas Andrius
Published: June 2018

Background and objective. Hepatic hypoperfusion is regarded as an important factor in the pathophysiology of perioperative liver injury. Although thoracic epidural anesthesia is a widely used technique, limited data are available about the effects on hepatic blood flow with blockade restricted to thoracic segments in humans. The main objective of the present study was to investigate the effects of thoracic epidural anesthesia on hepatic blood flow under general anesthesia in humans. Material and methods. In 40 patients under general anesthesia, we assessed hepatic blood flow using plasma disappearance rate of indocyanine green (PDRICG) as a simple noninvasive method before and after induction of thoracic epidural anesthesia. The epidural catheter was inserted at the Th7/8 or Th8/9, and 1% lidocaine at a mean (range) dose of 8 (6–10) mL was injected. Ephedrine bolus was given to patients who demonstrated a decrease in mean arterial blood pressure below 60 mm Hg after induction of thoracic epidural anesthesia (TEA-E group). Other patients did not receive any catecholamines during the study period (TEA group). Ten patients who did not undergo TEA served as controls (control group). Results. In 7 patients, administration of ephedrine was necessary to avoid a decrease in mean arterial blood pressure below 60 mm Hg. Thus, the TEA-E group consisted of 7 patients and TEA group of 33. In the TEA group, thoracic epidural anesthesia was associated with a mean 2.3% min–1 decrease in PDRICG (P<0.05). In the TEA-E group, all seven patients showed a 2.2% min–1decrease in PDRICG (P<0.05). Patients in the control group showed a mean 1.1% min–1 increase in PDRICG (P<0.05). In contrast to hepatic blood flow, cardiac output was not affected by thoracic epidural anesthesia. Conclusions. In humans, thoracic epidural anesthesia is associated with a decrease in hepatic blood flow. Thoracic epidural anesthesia combined with ephedrine bolus was found to result in further decrease in hepatic blood flow.
Colonic intussusception caused by colonic lipoma: A case report
Authors: Paškauskas Saulius , Latkauskas Tadas , Valeikaitė Gintarė , Paršeliūnas Audrius , Švagždys Saulius , Saladžinskas Žilvinas , Tamelis Algimantas , Pavalkis Dainius
Published: June 2018

Intussusception is a pediatric condition that rarely presents in adults. Colonic lipomas 4 cm and more in diameter can cause colonic intussusception leading to emergency operation. Surgical resection of the involved segment must be the procedure of choice. We report a case of colonic intussusception caused by colonic lipoma in an adult. The patient underwent operation, and histopathological examination of the specimen confirmed the diagnosis of colonic submucosal lipoma.
Associations of quality of sleep with lifestyle factors and profile of studies among Lithuanian students
Authors: Preišegolavičiūtė Evelina , Leskauskas Darius , Adomaitienė Virginija
Published: June 2018

The objective of the study was to analyze associations among quality of sleep, profile of the studies, and lifestyle factors among the students of three different study profiles (medicine, economics, and law). Material and methods. A total of 405 randomly selected students from the first and fourth years of studies from 4 different universities in Lithuania answered the standardized questionnaires consisting of two parts: 1) the Pittsburgh Sleep Quality Index (PSQI) for subjective evaluation of sleep quality; 2) the questionnaire about sleep and lifestyle habits and impact of poor sleep on the quality of life developed by the researchers. Results. More than half (59.4%) of the students scored higher than 5 on the PSQI, which allowed suspecting sleep disorders. A significant difference in the frequency of poor sleepers was found regarding the profile of studies (P<0.05) showing the highest frequency of sleep disturbances among medical students. There was a significant correlation between quality of sleep and subjective evaluation of quality of life (P<0.01). Medical students experienced the highest impact of poor sleep on the quality of life (P=0.008). Students studying before going to sleep, spending more time studying, and having less leisure time had worse quality of sleep (P<0.01). A significant difference was found among three profiles of studies regarding the anxiety about studies (P<0.0005) and subjective estimation of success in studies (χ²=27.9, P<0.0005), showing the highest anxiety and worst satisfaction among students of medicine. Conclusions. The incidence of sleep problems is high among students in Lithuania, reaching 59.4%. Medical students have worse quality of sleep and worse impact of poor sleep on the quality of life compared to students of law and economics. A significant difference was found between medical students and their peers in other profiles of studies regarding their attitudes and habits related to studies: medical students spent more time for studying, were more anxious about studies and less satisfied with the results, studied more often before going to sleep.
Pseudomonas aeruginosa bacteremia: resistance to antibiotics, risk factors, and patient mortality
Authors: Vitkauskienė Astra , Skrodenienė Erika , Dambrauskienė Asta , Macas Andrius , Sakalauskas Raimundas
Published: June 2018

The aim of our study was to determine the prevalence of Pseudomonas aeruginosa bacteremia, risk factors, and outcome of patients treated at the Hospital of Kaunas University of Medicine. Material and methods. All hospitalized patients with blood culture positive for Pseudomonas aeruginosa during the 5-year period were included. A retrospective data analysis was performed to evaluate patients’ risk factors and mortality caused by P. aeruginosa bacteremia. Results. A total of 47 (58.8%) bacteremia episodes occurred in an intensive care unit (ICU). A primary source of bacteremia was identified in 50 (62.5%) episodes. Overall mortality rate was 58.8%. Univariate risk factors analysis showed the factors, which significantly increased the risk of death: mechanical ventilation (13.67 times, P<0.001), patient hospitalization in the ICU (8.51 times, P<0.001), acute respiratory failure (8.44 times, P<0.001), infection site in the respiratory tract (4.93 times, P=0.003), and central vein catheter (4.44 times, P=0.002). Timely and appropriate treatment and surgery were significant protective factors for 30-day mortality (11.1 and 5.26 times, respectively; P=0.001). Meropenem-resistant Pseudomonas aeruginosa strains caused bacteremia more frequently in patients older than 65 years than meropenem-sensitive strains (57.9%, n=11). All 19 patients with meropenem-resistant Pseudomonas aeruginosa bacteremia received inappropriate empirical antibiotic therapy. Conclusions. Treatment at the intensive care unit, mechanical ventilation, acute respiratory failure, source of infection in respiratory tract, and central vein catheter are the major risk factors associated with an increased mortality rate in patients with Pseudomonas aeruginosa bacteremia. The patients older than 65 years are at increased risk for bacteremia caused by carbapenemresistant Pseudomonas aeruginosa strains. Carbapenems are not antibiotics of the choice of treatment for Pseudomonas aeruginosa bacteremia at the Hospital of Kaunas University of Medicine.
The influence of mean blood pressure on arterial stiffening and endothelial dysfunction in women with rheumatoid arthritis and systemic lupus erythematosus
Authors: Čypienė Alma , Dadonienė Jolanta , Rugienė Rita , Ryliškytė Ligita , Kovaitė Milda , Petrulionienė Žaneta , Venalis Algirdas , Laucevičius Aleksandras
Published: June 2018

Objective. To investigate the carotid-radial pulse wave velocity, augmentation index, and flow-mediated dilation of the brachial artery and factors possibly influencing them in women with rheumatoid arthritis and systemic lupus erythematosus. Material and methods. A total of 63 women with rheumatoid arthritis, 31 with systemic lupus erythematosus, and 72 controls, aged 18–55 years, were examined. Parameters of arterial stiffness, augmentation index and carotid-radial pulse wave velocity, were obtained by applanation tonometry (Sphygmocor (v.7.01) AtCor Medical). Flow-mediated dilatation of the brachial artery, reflecting endothelial function was determined by ultrasound system (Logiq 7, General Electric). Results. The groups of women with rheumatoid arthritis and systemic lupus erythematosus lupus differed from controls regarding augmentation index (P<0.001; P=0.008) and did not differ between each other. Women with systemic lupus erythematosus differed from controls regarding pulse wave velocity (P=0.018), while women with rheumatoid arthritis – did not. Flow-mediated dilatation in both the groups of diseases was not different from controls. In rheumatoid arthritis patients, mean blood pressure was the main explanatory factor for augmentation index and pulse wave velocity; vessel diameter and high-density lipoprotein cholesterol – for flow-mediated dilatation. In women with systemic lupus erythematosus, pulse wave velocity was not related to any of the pending parameters; augmentation index was dependent on organ damage index, age, and mean blood pressure, and flow-mediated dilatation on vessel diameter, body mass index, and disease duration. Conclusions. The mean blood pressure was the major and the only one risk factor of arterial stiffening in rheumatoid arthritis, while the disease damage index played the most important role in the systemic lupus erythematosus group. The mean blood pressure in the systemic lupus erythematosus group was not as important as in the rheumatoid arthritis group, though may have a partial influence.
Medium-Frequency Electrical Resistance Sintering of Oxidized C.P. Iron Powder
Authors: Montes Juan , Cuevas Francisco , Ternero Fátima , Astacio Raquel , Caballero Eduardo , Cintas Jesús
Published: June 2018

Commercially pure (C.P.) iron powders with a deliberate high degree of oxidation were consolidated by medium-frequency electrical resistance sintering (MF-ERS). This is a consolidation technique where pressure, and heat coming from a low-voltage and high-intensity electrical current, are simultaneously applied to a powder mass. In this work, the achieved densification rate is interpreted according to a qualitative microscopic model, based on the compacts global porosity and electrical resistance evolution. The effect of current intensity and sintering time on compacts was studied on the basis of micrographs revealing the porosity distribution inside the sintered compact. The microstructural characteristics of compacts consolidated by the traditional cold-press and furnace-sinter powder metallurgy route are compared with results of MF-ERS consolidation. The goodness of MF-ERS versus the problems of conventional sintering when working with oxidized powders is analyzed. The electrical consolidation can obtain higher densifications than the traditional route under non-reducing atmospheres.
Thermal Stability and Lubrication Properties of Biodegradable Castor Oil on AISI 4140 Steel
Authors: Hernández-Sierra María Teresa , Aguilera-Camacho Luis Daniel , Báez-García José Eduardo , García-Miranda J. Santos , Moreno Karla J.
Published: June 2018

Lubricants have much importance in several industries, principally serving to reduce friction and wear in mechanical elements. In this study, the influence of Castor oil as bio-lubricant on the friction and wear performance of AISI 4140 steel was investigated. For that purpose, pin-on-disk friction tests were conducted according to ASTM G-99, by using pins of tungsten carbide (WC) as counterparts. The experiments were performed at two different temperatures. This work also presents the Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR) and 1H-NMR analyses for the chemical characterization of oils and a study of their degradation by oxidation. The analysis of the damage caused to steel due to friction was deepened by analyzing its microhardness and microstructure in the worn zone. As a reference, the same experiments were performed with a commercial oil. The friction behavior of 4140 steel/WC with Castor oil lubrication at the two temperatures was notably better than that obtained under the reference oil lubrication. The kinetic friction coefficient (µk) was up to 76% lower. However, a slight increase in steel wear was observed under Castor oil lubrication. Despite this, these results suggest that Castor oil could be used as bio-lubricant in systems which are susceptible to levels of high friction.
Nanoliter Centrifugal Liquid Dispenser Coupled with Superhydrophobic Microwell Array Chips for High-Throughput Cell Assays
Authors: Wang Yuyi , Wu Yushuai , Chen Yue , Zhang Jianxiong , Chen Xiaofang , Liu Peng
Published: June 2018

Microfluidic systems have been regarded as a potential platform for high-throughput screening technology in drug discovery due to their low sample consumption, high integration, and easy operation. The handling of small-volume liquid is an essential operation in microfluidic systems, especially in investigating large-scale combination conditions. Here, we develop a nanoliter centrifugal liquid dispenser (NanoCLD) coupled with superhydrophobic microwell array chips for high-throughput cell-based assays in the nanoliter scale. The NanoCLD consists of a plastic stock block with an array of drilled through holes, a reagent microwell array chip (reagent chip), and an alignment bottom assembled together in a fixture. A simple centrifugation at 800 rpm can dispense ~160 nL reagents into microwells in 5 min. The dispensed reagents are then delivered to cells by sandwiching the reagent chip upside down with another microwell array chip (cell chip) on which cells are cultured. A gradient of doxorubicin is then dispensed to the cell chip using the NanoCLD for validating the feasibility of performing drug tests on our microchip platform. This novel nanoliter-volume liquid dispensing method is simple, easy to operate, and especially suitable for repeatedly dispensing many different reagents simultaneously to microwells.
The Pentatricopeptide Repeat Gene Family in Salvia miltiorrhiza: Genome-Wide Characterization and Expression Analysis
Authors: Li Heqin , Li Caili , Deng Yuxing , Jiang Xuwen , Lu Shanfa
Published: June 2018

The pentatricopeptide repeat (PPR) gene family is one of the largest gene families in plants and plays important roles in posttranscriptional regulation. In this study, we combined whole genome sequencing and transcriptomes to systematically investigate PPRs in Salvia miltiorrhiza, which is a well-known material of traditional Chinese medicine and an emerging model system for medicinal plant studies. Among 562 identified SmPPRs, 299 belong to the P subfamily while the others belong to the PLS subfamily. The majority of SmPPRs have only one exon and are localized in the mitochondrion or chloroplast. As many as 546 SmPPRs were expressed in at least one tissue and exhibited differential expression patterns, which indicates they likely play a variety of functions in S. miltiorrhiza. Up to 349 SmPPRs were salicylic acid-responsive and 183 SmPPRs were yeast extract and Ag+-responsive, which indicates these genes might be involved in S. miltiorrhiza defense stresses and secondary metabolism. Furthermore, 23 salicylic acid-responsive SmPPRs were co-expressed with phenolic acid biosynthetic enzyme genes only while 16 yeast extract and Ag+-responsive SmPPRs were co-expressed with tanshinone biosynthetic enzyme genes only. Two SmPPRs were co-expressed with both phenolic acid and tanshinone biosynthetic enzyme genes. The results provide a useful platform for further investigating the roles of PPRs in S. miltiorrhiza.
Discovering Structural Motifs in miRNA Precursors from the Viridiplantae Kingdom
Authors: Miskiewicz Joanna , Szachniuk Marta
Published: June 2018

A small non-coding molecule of microRNA (19–24 nt) controls almost every biological process, including cellular and physiological, of various organisms’ lives. The amount of microRNA (miRNA) produced within an organism is highly correlated to the organism’s key processes, and determines whether the system works properly or not. A crucial factor in plant biogenesis of miRNA is the Dicer Like 1 (DCL1) enzyme. Its responsibility is to perform the cleavages in the miRNA maturation process. Despite everything we already know about the last phase of plant miRNA creation, recognition of miRNA by DCL1 in pre-miRNA structures of plants remains an enigma. Herein, we present a bioinformatic procedure we have followed to discover structure patterns that could guide DCL1 to perform a cleavage in front of or behind an miRNA:miRNA* duplex. The patterns in the closest vicinity of microRNA are searched, within pre-miRNA sequences, as well as secondary and tertiary structures. The dataset consists of structures of plant pre-miRNA from the Viridiplantae kingdom. The results confirm our previous observations based on Arabidopsis thaliana precursor analysis. Hereby, our hypothesis was tested on pre-miRNAs, collected from the miRBase database to show secondary structure patterns of small symmetric internal loops 1-1 and 2-2 at a 1–10 nt distance from the miRNA:miRNA* duplex.
Structure–Activity Relationship and Molecular Docking of Natural Product Library Reveal Chrysin as a Novel Dipeptidyl Peptidase-4 (DPP-4) Inhibitor: An Integrated In Silico and In Vitro Study
Authors: Kalhotra Poonam , Chittepu Veera C. S. R. , Osorio-Revilla Guillermo , Gallardo-Velázquez Tzayhri
Published: June 2018

Numerous studies indicate that diets with a variety of fruits and vegetables decrease the incidence of severe diseases, like diabetes, obesity, and cancer. Diets contain a variety of bioactive compounds, and their features, like diverge scaffolds, and structural complexity make them the most successful source of potential leads or hits in the process of drug discovery and drug development. Recently, novel serine protease dipeptidyl peptidase-4 (DPP-4) inhibitors played a role in the management of diabetes, obesity, and cancer. This study describes the development of field template, field-based qualitative structure–activity relationship (SAR) model demonstrating DPP-4 inhibitors of natural origin, and the same model is used to screen virtually focused food database composed of polyphenols as potential DPP-4 inhibitors. Compounds’ similarity to field template, and novelty score “high and very high”, were used as primary criteria to identify novel DPP-4 inhibitors. Molecular docking simulations were performed on the resulting natural compounds using FlexX algorithm. Finally, one natural compound, chrysin, was chosen to be evaluated experimentally to demonstrate the applicability of constructed SAR model. This study provides the molecular insights necessary in the discovery of new leads as DPP-4 inhibitors, to improve the potency of existing DPP-4 natural inhibitors.
Biosynthesis of Fluorescent β Subunits of C-Phycocyanin from Spirulina subsalsa in Escherichia coli, and Their Antioxidant Properties
Authors: Wu Xian-Jun , Yang Hong , Chen Yu-Ting , Li Ping-Ping
Published: June 2018

Phycocyanin, which covalently binds phycocyanobilin chromophores, is not only a candidate fluorescent probe for biological imaging, but also a potential antioxidative agent for healthcare. Herein, a plasmid harboring two cassettes was constructed, with cpcB from Spirulina subsalsa in one cassette and the fusion gene cpcS::ho1::pcyA in the other, and then expressed in Escherichia coli. PCB-CpcB(C-82), a fluorescent phycocyanin β subunit, was biosynthesized in E. coli, exhibiting an absorption maximum at 620 nm and fluorescence emission maximum at 640 nm. When cpcS was replaced by cpcT, PCB-CpcB(C-153), another fluorescent phycocyanin β subunit, was produced, exhibiting an absorption maximum at 590 nm and fluorescence emission maximum at 620 nm. These two fluorescent biliproteins showed stronger scavenging activity toward hydroxyl and DPPH free radicals than apo-CpcB. The IC50 values for hydroxyl radical scavenging by PCB-CpcB(C-82), PCB-CpcB(C-153), and apo-CpcB were 38.72 ± 2.48 µg/mL, 51.06 ± 6.74 µg/mL, and 81.82 ± 0.67 µg/mL, respectively, and the values for DPPH radical scavenging were 201.00 ± 5.86 µg/mL, 240.34 ± 4.03 µg/mL, and 352.93 ± 26.30 µg/mL, respectively. The comparative antioxidant capacities of the proteins were PCB-CpcB(C-82) > PCB-CpcB(C-153) > apo-CpcB, due to bilin binding. The two fluorescent biliproteins exhibited a significant effect on relieving the growth of E. coli cells injured by H2O2. The results of this study suggest that the fluorescent phycocyanin β subunits of S. subsalsa were reconstructed by one expression vector in E. coli, and could be developed as potential antioxidants.
Aerosol Synthesis of N and N-S Doped and Crumpled Graphene Nanostructures
Authors: Carraro Francesco , Cattelan Mattia , Favaro Marco , Calvillo Laura
Published: June 2018

Chemically modified graphene–based materials (CMG) are currently attracting a vast interest in their application in different fields. In particular, heteroatom-doped graphenes have revealed great potentialities in the field of electrocatalysis as substitutes of fuel cell noble metal–based catalysts. In this work, we investigate an innovative process for doping graphene nanostructures. We optimize a novel synthetic route based on aerosol preparation, which allows the simultaneous doping, crumpling, and reduction of graphene oxide (GO). Starting from aqueous solutions containing GO and the dopant precursors, we synthesize N- and N,S-dual-doped 3D graphene nanostructures (N-cGO and N,S-cGO). In the aerosol process, every aerosol droplet can be considered as a microreactor where dopant precursors undergo thermal decomposition and react with the GO flakes. Simultaneously, thanks to the relatively high temperature, GO undergoes crumpling and partial reduction. Using a combination of spectroscopic and microscopic characterization techniques, we investigate the morphology of the obtained materials and the chemical nature of the dopants within the crumpled graphene sheets. This study highlights the versatility of the aerosol process for the design of new CMG materials with tailored electrocatalytic properties.