bluuebunny/crossref_metadata_2025 huggingface dataset:
Survivability Analysis on a Cyber-Physical System
Authors: Wang Ti , Zhang Zuyuan , Shao Fangming
Published: August 2017

A cyber-physical system (CPS) is composed of interdependent physical-resource and cyber-resource networks that are tightly coupled. The malfunction of nodes in a network may trigger failures to the other network and further cause cascading failures, which would potentially lead to the complete collapse of the entire system. The number and communication of operating nodes at stable state are closely related to the initial failure nodes and the topology of the network system. To address this issue, this paper studies the survivability of CPS in the presence of initial failure nodes, proposes (m, k)—survivability, which is defined as the probability that at least k nodes are still working in CPS after m nodes are attacked, and discusses the problem of cascading failure based on reliability (CFR). Further, we propose an algorithm to calculate (m, k)—survivability and find that the minimum survivability of system with regular allocation strategy decreases with k for a fixed m, and the proportion of initial failure node groups that cause the system to completely fragment increases with m. The simulation shows the properties and the result of CFR of the system with 12 nodes.
Use of Antibiotics for Maintenance of Axenic Cultures of Amphidinium carterae for the Analysis of Translation
Authors: Liu Chieh-Lun , Place Allen R. , Jagus Rosemary
Published: August 2017

Most dinoflagellates in culture are bacterized, complicating the quantification of protein synthesis, as well as the analysis of its regulation. In bacterized cultures of Amphidinium carterae Hulbert, up to 80% of protein synthetic activity appears to be predominantly bacterial based on responses to inhibitors of protein synthesis. To circumvent this, axenic cultures of A. carterae were obtained and shown to respond to inhibitors of protein synthesis in a manner characteristic of eukaryotes. However, these responses changed with time in culture correlating with the reappearance of bacteria. Here we show that culture with kanamycin (50 μg/mL), carbenicillin (100 μg/mL), and streptomycin sulfate (50 μg/mL) (KCS), but not 100 units/mL of penicillin and streptomycin (PS), prevents the reappearance of bacteria and allows A. carterae protein synthesis to be quantified without the contribution of an associated bacterial community. We demonstrate that A. carterae can grow in the absence of a bacterial community. Furthermore, maintenance in KCS does not inhibit the growth of A. carterae cultures but slightly extends the growth phase and allows accumulation to somewhat higher saturation densities. We also show that cultures of A. carterae maintained in KCS respond to the eukaryotic protein synthesis inhibitors cycloheximide, emetine, and harringtonine. Establishment of these culture conditions will facilitate our ability to use polysome fractionation and ribosome profiling to study mRNA recruitment. Furthermore, this study shows that a simple and fast appraisal of the presence of a bacterial community in A. carterae cultures can be made by comparing responses to cycloheximide and chloramphenicol rather than depending on lengthier culture-based assessments.
Effects of Pulsed Nd:YAG Laser Welding Parameters on Penetration and Microstructure Characterization of a DP1000 Steel Butt Joint
Authors: Xue Xin , Pereira António , Amorim José , Liao Juan
Published: August 2017

Of particular importance and interest are the effects of pulsed Nd:YAG laser beam welding parameters on penetration and microstructure characterization of DP1000 butt joint, which is widely used in the automotive industry nowadays. Some key experimental technologies including pre-welding sample preparation and optimization design of sample fixture for a sufficient shielding gas flow are performed to ensure consistent and stable testing. The weld quality can be influenced by several process factors, such as laser beam power, pulse duration, overlap, spot diameter, pulse type, and welding velocity. The results indicate that these key process parameters have a significant effect on the weld penetration. Meanwhile, the fusion zone of butt joints exhibits obviously greater hardness than the base metal and heat affected zone of butt joints. Additionally, the volume fraction of martensite of dual-phase steel plays a considerable effect on the hardness and the change of microstructure characterization of the weld joint.
Volatile Metabolites Emission by In Vivo Microalgae—An Overlooked Opportunity?
Authors: Achyuthan Komandoor , Harper Jason , Manginell Ronald , Moorman Matthew
Published: August 2017

Fragrances and malodors are ubiquitous in the environment, arising from natural and artificial processes, by the generation of volatile organic compounds (VOCs). Although VOCs constitute only a fraction of the metabolites produced by an organism, the detection of VOCs has a broad range of civilian, industrial, military, medical, and national security applications. The VOC metabolic profile of an organism has been referred to as its ‘volatilome’ (or ‘volatome’) and the study of volatilome/volatome is characterized as ‘volatilomics’, a relatively new category in the ‘omics’ arena. There is considerable literature on VOCs extracted destructively from microalgae for applications such as food, natural products chemistry, and biofuels. VOC emissions from living (in vivo) microalgae too are being increasingly appreciated as potential real-time indicators of the organism’s state of health (SoH) along with their contributions to the environment and ecology. This review summarizes VOC emissions from in vivo microalgae; tools and techniques for the collection, storage, transport, detection, and pattern analysis of VOC emissions; linking certain VOCs to biosynthetic/metabolic pathways; and the role of VOCs in microalgae growth, infochemical activities, predator-prey interactions, and general SoH.
Bleeding Characteristics and Improving Mechanism of Self-Flowing Tailings Filling Slurry with Low Concentration
Authors: Liu Juanhong , Wu Ruidong , Wu Aixiang , Wang Shaoyong
Published: August 2017

In order to solve the bleeding problem of self-flowing tailings filling slurry with low concentration, the influences of the dosage of special additive on the bleeding rate were investigated. The improving mechanism of special additive on the bleeding of tailings filling slurry was studied by measuring the bleeding rate and compressive strength of the slurry. Also, microstruture analysis was conducted by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and infrared spectroscopy (IR) of the hardened body. The results show that with the slurry concentration of 60%, the binder-to-tailings ratio of 1:6 and the special additive dosage of 10%, the filling slurry is not bleeding and the compressive strength of hardened body can increase by 43.5% at three days. A large amount of needle-like ettringite is generated in the hardened body after adding the special additive, and the structure becomes denser. The special additive can effectively improve the bleeding of the filling slurry and increase the compressive strength of the filling material at early age.
Molecular Cloning and Characterization of PnbHLH1 Transcription Factor in Panax notoginseng
Authors: Zhang Xiang , Ge Feng , Deng Bing , Shah Taif , Huang Zhuangjia , Liu Diqiu , Chen Chaoyin
Published: August 2017

Panax notoginseng has been extensively used as a traditional Chinese medicine. In the current study, molecular cloning and characterization of PnbHLH1 transcription factor were explored in Panax notoginseng. The full length of the PnbHLH1 gene obtained by splicing was 1430 bp, encoding 321 amino acids. Prokaryotic expression vector pET-28a-PnbHLH1 was constructed and transferred into the BL21 prokaryotic expression strain. An electrophoretic mobility shift assay of PnbHLH1 protein binding to E-box cis-acting elements verified that PnbHLH1 belonged to the bHLH class transcription factor which could interact with the promoter region of the E-box core sequence. The expression levels of key genes involved in the biosynthesis of triterpenoid saponins in PnbHLH1 transgenic cells were higher than those in the wild cells. Similarly, the total saponin contents were increased in the PnbHLH1 transgenic cell lines compared with the wild cell lines. Such results suggest that the PnbHLH1 transcription factor is a positive regulator in the biosynthesis of triterpenoid saponins in Panax notoginseng.
β-Formyl- and β-Vinylporphyrins: Magic Building Blocks for Novel Porphyrin Derivatives
Authors: Cerqueira Ana , Moura Nuno , Serra Vanda , Faustino M. , Tomé Augusto , Cavaleiro José , Neves M.
Published: August 2017

Porphyrins bearing formyl or vinyl groups have been explored as starting materials to prepare new compounds with adequate features for different applications. In this review it is discussed mainly synthetic strategies based on the reaction of meso-tetraarylporphyrins bearing those groups at β-pyrrolic positions. The use of some of the obtained porphyrin derivatives for further transformations, namely via pericyclic reactions, is also highlighted.
Research Progress in the Modification of Quercetin Leading to Anticancer Agents
Authors: Massi Alessandro , Bortolini Olga , Ragno Daniele , Bernardi Tatiana , Sacchetti Gianni , Tacchini Massimo , De Risi Carmela
Published: August 2017

The flavonoid quercetin (3,3′,4′,5,7-pentahydroxyflavone) is widely distributed in plants, foods, and beverages. This polyphenol compound exhibits varied biological actions such as antioxidant, radical-scavenging, anti-inflammatory, antibacterial, antiviral, gastroprotective, immune-modulator, and finds also application in the treatment of obesity, cardiovascular diseases and diabetes. Besides, quercetin can prevent neurological disorders and exerts protection against mitochondrial damages. Various in vitro studies have assessed the anticancer effects of quercetin, although there are no conclusive data regarding its mode of action. However, low bioavailability, poor aqueous solubility as well as rapid body clearance, fast metabolism and enzymatic degradation hamper the use of quercetin as therapeutic agent, so intense research efforts have been focused on the modification of the quercetin scaffold to obtain analogs with potentially improved properties for clinical applications. This review gives an overview of the developments in the synthesis and anticancer-related activities of quercetin derivatives reported from 2012 to 2016.
CeO2 Nanorods Embedded in Ni(OH)2 Matrix for the Non-Enzymatic Detection of Glucose
Authors: Li Yongjian , Guan Panpan , Yu Fucheng , Li Wei , Xie Xiaoling
Published: August 2017

The electrode based on cerium oxide (CeO2) nanorods embedded in nickel hydroxide (Ni(OH)2) matrix were prepared and used for detecting glucose non-enzymatically. The materials were characterized by X-ray diffraction, transmission electron microscopy (TEM), and so on. The results indicate that the response of CeO2/Ni(OH)2 nanocomposite are significantly improved due to the synergetic effect between CeO2 and Ni(OH)2. The optimum CeO2/Ni(OH)2 nanocomposite electrode exhibits a detection range from 2 μM to 6.62 mM, a sensitivity of 594 μA mM−1 cm−2, an estimated detection limit of 1.13 μM, and a response time less than 5 s. In addition, this biosensor also shows good selectivity, long term stability, and accurate measurement in juice on sale.
N-Doped TiO2-Coated Ceramic Membrane for Carbamazepine Degradation in Different Water Qualities
Authors: Luster Enbal , Avisar Dror , Horovitz Inna , Lozzi Luca , Baker Mark , Grilli Rossana , Mamane Hadas
Published: August 2017

The photocatalytic degradation of the model pollutant carbamazepine (CBZ) was investigated under simulated solar irradiation with an N-doped TiO2-coated Al2O3 photocatalytic membrane, using different water types. The photocatalytic membrane combines photocatalysis and membrane filtration in a single step. The impact of each individual constituent such as acidity, alkalinity, dissolved organic matter (DOM), divalent cations (Mg2+ and Ca2+), and Cl− on the degradation of CBZ was examined. CBZ in water was efficiently degraded by an N-doped TiO2-coated Al2O3 membrane. However, elements added to the water, which simulate the constituents of natural water, had an impact on the CBZ degradation. Water alkalinity inhibited CBZ degradation mostly due to increase in pH while radical scavenging by carbonate was more dominant at higher values (>200 mg/L as CaCO3). A negative effect of Ca2+ addition on photocatalytic degradation was found only in combination with phosphate buffer, probably caused by deposition of CaHPO4 or CaHPO4·2H2O on the catalyst surface. The presence of Cl− and Mg2+ ions had no effect on CBZ degradation. DOM significantly inhibited CBZ degradation for all tested background organic compounds. The photocatalytic activity of N-doped TiO2-coated Al2O3 membranes gradually decreased after continuous use; however, it was successfully regenerated by 0.1% HCl chemical cleaning. Nevertheless, dissolution of metals like Al and Ti should be monitored following acid cleaning.
Effects of PLA Film Incorporated with ZnO Nanoparticle on the Quality Attributes of Fresh-Cut Apple
Authors: Li Wenhui , Li Lin , Cao Yun , Lan Tianqing , Chen Haiyan , Qin Yuyue
Published: August 2017

A novel nanopackaging film was synthesized by incorporating ZnO nanoparticles into a poly-lactic acid (PLA) matrix, and its effect on the quality of fresh-cut apple during the period of preservation was investigated at 4 ± 1 °C for 14 days. Six wt % cinnamaldehyde was added into the nano-blend film. Scanning electron microscope (SEM) analysis showed a rougher cross-section of the nano-blend films and an X-ray diffraction (XRD) was carried out to determine the structure of the ZnO nanoparticles. Compared to the pure PLA film, the nano-blend film had a higher water vapor permeability (WVP) and lower oxygen permeability. With the increase of the nanoparticles (NPs) in the PLA, the elongation at break (ε) and elastic modulus (EM) increased, while tensile strength (TS) decreased. Thermogravimetric analysis (TGA) presented a relatively good thermostability. Most importantly, the physical and biochemical properties of the fresh-cut apple were also measured, such as weight loss, firmness, polyphenol oxidase (PPO), total phenolic content, browning index (BI), sensory quality, and microbiological level. The results indicated that nano-blend packaging films had the highest weight loss at the end of storage compared to the pure PLA film; however, nanopackaging provided a better retention of firmness, total phenolic countent, color, and sensory quality. It also had a remarkable inhibition on the growth of microorganisms. Therefore, Nano-ZnO active packaging could be used to improve the shelf-life of fresh-cut produce.
Fruit and Vegetable Intake Patterns and Their Associations with Sociodemographic Characteristics, Anthropometric Status and Nutrient Intake Profiles among Malaysian Children Aged 1–6 Years
Authors: Chong Kar , Lee Shoo , Ng Swee , Khouw Ilse , Poh Bee
Published: August 2017

This study aimed to assess fruit and vegetable intake patterns and their associations with sociodemographic characteristics, anthropometric status and nutrient intake profiles among Malaysian children aged 1–6 years. Using the Malaysian dataset of South East Asian Nutrition Surveys (SEANUTS Malaysia), a total of 1307 children aged 1–6 years with complete datasets were included in this analysis. Dietary intake was assessed using age-specific, validated food frequency questionnaires. On average, Malaysian children consumed 0.91 and 1.07 servings of fruits and vegetables per day, respectively. Less than one-fifth of the children achieved the daily recommended servings of fruits (11.7%) and vegetables (15.8%). Fruit intake was associated with age, parental educational level and geographical region, and vegetable intake was associated with ethnicity and geographical region. There was little evidence of an association between fruit and vegetable intake and children’s anthropometric status, but an adequate intake of fruits and vegetables contributed significantly and differently to children’s micronutrient intake. Future nutrition interventions should focus on addressing the sociodemographic determinants and be tailored to the needs of the low consumers to more effectively promote and encourage the adequate intake of fruit and vegetables among young children.
A Single Day of Excessive Dietary Fat Intake Reduces Whole-Body Insulin Sensitivity: The Metabolic Consequence of Binge Eating
Authors: Parry Siôn , Woods Rachel , Hodson Leanne , Hulston Carl
Published: August 2017

Consuming excessive amounts of energy as dietary fat for several days or weeks can impair glycemic control and reduce insulin sensitivity in healthy adults. However, individuals who demonstrate binge eating behavior overconsume for much shorter periods of time; the metabolic consequences of such behavior remain unknown. The aim of this study was to determine the effect of a single day of high-fat overfeeding on whole-body insulin sensitivity. Fifteen young, healthy adults underwent an oral glucose tolerance test before and after consuming a high-fat (68% of total energy), high-energy (78% greater than daily requirements) diet for one day. Fasting and postprandial plasma concentrations of glucose, insulin, non-esterified fatty acids, and triglyceride were measured and the Matsuda insulin sensitivity index was calculated. One day of high-fat overfeeding increased postprandial glucose area under the curve (AUC) by 17.1% (p < 0.0001) and insulin AUC by 16.4% (p = 0.007). Whole-body insulin sensitivity decreased by 28% (p = 0.001). In conclusion, a single day of high-fat, overfeeding impaired whole-body insulin sensitivity in young, healthy adults. This highlights the rapidity with which excessive consumption of calories through high-fat food can impair glucose metabolism, and suggests that acute binge eating may have immediate metabolic health consequences for the individual.
Effects of Pomegranate Juice Supplementation on Oxidative Stress Biomarkers Following Weightlifting Exercise
Authors: Ammar Achraf , Turki Mouna , Hammouda Omar , Chtourou Hamdi , Trabelsi Khaled , Bouaziz Mohamed , Abdelkarim Osama , Hoekelmann Anita , Ayadi Fatma , Souissi Nizar , Bailey Stephen , Driss Tarak , Yaich Sourour
Published: August 2017

The aim of this study was to test the hypothesis that pomegranate juice supplementation would blunt acute and delayed oxidative stress responses after a weightlifting training session. Nine elite weightlifters (21.0 ± 1 years) performed two Olympic-Weightlifting sessions after ingesting either the placebo or pomegranate juice supplements. Venous blood samples were collected at rest and 3 min and 48 h after each session. Compared to the placebo condition, pomegranate juice supplementation attenuated the increase in malondialdehyde (−12.5%; p < 0.01) and enhanced the enzymatic (+8.6% for catalase and +6.8% for glutathione peroxidase; p < 0.05) and non-enzymatic (+12.6% for uric acid and +5.7% for total bilirubin; p < 0.01) antioxidant responses shortly (3 min) after completion of the training session. Additionally, during the 48 h recovery period, pomegranate juice supplementation accelerated (p < 0.05) the recovery kinetics of the malondialdehyde (5.6%) and the enzymatic antioxidant defenses compared to the placebo condition (9 to 10%). In conclusion, supplementation with pomegranate juice has the potential to attenuate oxidative stress by enhancing antioxidant responses assessed acutely and up to 48 h following an intensive weightlifting training session. Therefore, elite weightlifters might benefit from blunted oxidative stress responses following intensive weightlifting sessions, which could have implications for recovery between training sessions.
Dietary Approaches in the Management of Diabetic Patients with Kidney Disease
Authors: Ko Gang , Kalantar-Zadeh Kamyar , Goldstein-Fuchs Jordi , Rhee Connie
Published: August 2017

Chronic kidney disease (CKD) is one of the most prevalent complications of diabetes, and patients with diabetic kidney disease (DKD) have a substantially higher risk of cardiovascular disease and death compared to their non-diabetic CKD counterparts. In addition to pharmacologic management strategies, nutritional and dietary interventions in DKD are an essential aspect of management with the potential for ameliorating kidney function decline and preventing the development of other end-organ complications. Among DKD patients with non-dialysis dependent CKD, expert panels recommend lower dietary protein intake of 0.8 g/kg of body weight/day, while higher dietary protein intake (>1.2 g/kg of body weight/day) is advised among diabetic end-stage renal disease patients receiving maintenance dialysis to counteract protein catabolism, dialysate amino acid and protein losses, and protein-energy wasting. Carbohydrates from sugars should be limited to less than 10% of energy intake, and it is also suggested that higher polyunsaturated and monounsaturated fat consumption in lieu of saturated fatty acids, trans-fat, and cholesterol are associated with more favorable outcomes. While guidelines recommend dietary sodium restriction to less than 1.5–2.3 g/day, excessively low sodium intake may be associated with hyponatremia as well as impaired glucose metabolism and insulin sensitivity. As patients with advanced DKD progressing to end-stage renal disease may be prone to the “burnt-out diabetes” phenomenon (i.e., spontaneous resolution of hypoglycemia and frequent hypoglycemic episodes), further studies in this population are particularly needed to determine the safety and efficacy of dietary restrictions in this population.
The Linoleic Acid: Dihomo-γ-Linolenic Acid Ratio (LA:DGLA)—An Emerging Biomarker of Zn Status
Authors: Knez Marija , Stangoulis James , Glibetic Maria , Tako Elad
Published: August 2017

Zinc (Zn) deficiency is a common aliment predicted to affect 17% of the world’s population. Zinc is a vital micronutrient used for over 300 enzymatic reactions and multiple biochemical and structural processes in the body. Although whole blood, plasma, and urine zinc decrease in severe zinc deficiency, accurate assessment of zinc status, especially in mild to moderate deficiency, is difficult as studies with these biomarkers are often contradictory and inconsistent. Hence, as suggested by the World Health Organization, sensitive and specific biological markers of zinc status are still needed. In this review, we provide evidence to demonstrate that the LA:DGLA ratio (linoleic acid:dihomo-γ-linolenic acid ratio) may be a useful additional indicator for assessing Zn status more precisely. However, this biomarker needs to be tested further in order to determine its full potential.
Omega-3 Fatty Acids Supplementation Differentially Modulates the SDF-1/CXCR-4 Cell Homing Axis in Hypertensive and Normotensive Rats
Authors: Halmenschlager Luiza , Lehnen Alexandre , Marcadenti Aline , Markoski Melissa
Published: August 2017

Background: We assessed the effect of acute and chronic dietary supplementation of ω-3 on lipid metabolism and cardiac regeneration, through its influence on the Stromal Derived Factor-1 (SDF-1) and its receptor (CXCR4) axis in normotensive and hypertensive rats. Methods: Male Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHR) were allocated in eight groups (of eight animals each), which received daily orogastric administration of ω-3 (1 g) for 24 h, 72 h or 2 weeks. Blood samples were collected for the analysis of the lipid profile and SDF-1 systemic levels (ELISA). At the end of the treatment period, cardiac tissue was collected for CXCR4 expression analysis (Western blot). Results: The use of ω-3 caused a reduction in total cholesterol levels (p = 0.044), and acutely activated the SDF-1/CXCR4 axis in normotensive animals (p = 0.037). In the presence of the ω-3, after 72 h, SDF-1 levels decreased in WKY and increased in SHR (p = 0.017), and tissue expression of the receptor CXCR4 was higher in WKY than in SHR (p = 0.001). Conclusion: The ω-3 fatty acid supplementation differentially modulates cell homing mediators in normotensive and hypertensive animals. While WKY rats respond acutely to omega-3 supplementation, showing increased release of SDF-1 and CXCR4, SHR exhibit a weaker, delayed response.
The Binding Effect of Proteins on Medications and Its Impact on Electrochemical Sensing: Antipsychotic Clozapine as a Case Study
Authors: Banis George , Winkler Thomas , Barton Patricia , Chocron Sheryl , Kim Eunkyoung , Kelly Deanna , Payne Gregory , Ben-Yoav Hadar , Ghodssi Reza
Published: August 2017

Clozapine (CLZ), a dibenzodiazepine, is demonstrated as the optimal antipsychotic for patients suffering from treatment-resistant schizophrenia. Like many other drugs, understanding the concentration of CLZ in a patient’s blood is critical for managing the patients’ symptoms, side effects, and overall treatment efficacy. To that end, various electrochemical techniques have been adapted due to their capabilities in concentration-dependent sensing. An open question associated with electrochemical CLZ monitoring is whether drug–protein complexes (i.e., CLZ bound to native blood proteins, such as serum albumin (SA) or alpha-1 acid-glycoprotein (AAG)) contribute to electrochemical redox signals. Here, we investigate CLZ-sensing performance using fundamental electrochemical methods with respect to the impact of protein binding. Specifically, we test the activity of bound and free fractions of a mixture of CLZ and either bovine SA or human AAG. Results suggest that bound complexes do not significantly contribute to the electrochemical signal for mixtures of CLZ with AAG or SA. Moreover, the fraction of CLZ bound to protein is relatively constant at 31% (AAG) and 73% (SA) in isolation with varying concentrations of CLZ. Thus, electrochemical sensing can enable direct monitoring of only the unbound CLZ, previously only accessible via equilibrium dialysis. The methods utilized in this work offer potential as a blueprint in developing electrochemical sensors for application to other redox-active medications with high protein binding more generally. This demonstrates that electrochemical sensing can be a new tool in accessing information not easily available previously, useful toward optimizing treatment regimens.
Biodegradable Core–Multishell Nanocarriers: Influence of Inner Shell Structure on the Encapsulation Behavior of Dexamethasone and Tacrolimus
Authors: Unbehauen Michael , Fleige Emanuel , Paulus Florian , Schemmer Brigitta , Mecking Stefan , Moré Sam , Haag Rainer
Published: August 2017

We here present the synthesis and characterization of a set of biodegradable core–multishell (CMS) nanocarriers. The CMS nanocarrier structure consists of hyperbranched polyglycerol (hPG) as core material, a hydrophobic (12, 15, 18, 19, and 36 C-atoms) inner and a polyethylene glycol monomethyl ether (mPEG) outer shell that were conjugated by ester bonds only to reduce the toxicity of metabolites. The loading capacities (LC) of the drugs, dexamethasone and tacrolimus, and the aggregate formation, phase transitions, and degradation kinetics were determined. The intermediate inner shell length (C15) system had the best overall performance with good LCs for both drugs as well as a promising degradation and release kinetics, which are of interest for dermal delivery.
Manipulating Living Cells to Construct a 3D Single-Cell Assembly without an Artificial Scaffold
Authors: Yoshida Aoi , Tsuji Shoto , Taniguchi Hiroaki , Kenmotsu Takahiro , Sadakane Koichiro , Yoshikawa Kenichi
Published: August 2017

Artificial scaffolds such as synthetic gels or chemically-modified glass surfaces that have often been used to achieve cell adhesion are xenobiotic and may harm cells. To enhance the value of cell studies in the fields of regenerative medicine and tissue engineering, it is becoming increasingly important to create a cell-friendly technique to promote cell–cell contact. In the present study, we developed a novel method for constructing stable cellular assemblies by using optical tweezers in a solution of a natural hydrophilic polymer, dextran. In this method, a target cell is transferred to another target cell to make cell–cell contact by optical tweezers in a culture medium containing dextran. When originally non-cohesive cells are held in contact with each other for a few minutes under laser trapping, stable cell–cell adhesion is accomplished. This method for creating cellular assemblies in the presence of a natural hydrophilic polymer may serve as a novel next-generation 3D single-cell assembly system with future applications in the growing field of regenerative medicine.
One-Pot Synthesis of Charged Amphiphilic Diblock and Triblock Copolymers Via High-Throughput Cu(0)-Mediated Polymerization
Authors: Voorhaar Lenny , Hoogenboom Richard
Published: August 2017

Block copolymers containing functionalized monomers, for example those containing charged groups, can be used for many purposes, one of which is the design of polymeric supramolecular materials based on electrostatic interactions. In this paper the synthesis of diblock copolymers and ABA-triblock copolymers containing poly(n-butyl acrylate) as a first or middle block and poly(2-(dimethylamino)ethyl acrylate), poly(1-ethoxyethyl acrylate) and poly(1-ethoxyethyl-2-carboxyethyl acrylate) as second or outer blocks, resulting in block copolymers that can contain positive or negative charges, is reported. The polymerizations were performed and optimized via one-pot sequential monomer addition reactions via Cu(0)-mediated polymerization using an automated parallel synthesizer. Different initiators, monomer concentrations and polymerization times were tested. While a bromide-containing initiator led to the best results for most monomers, when polymerizing 2-(dimethylamino)ethyl acrylate the use of a chloride-containing initiator was necessary. Due to the slower polymerization using this initiator, a longer polymerization time was needed before addition of the second monomer. Using the optimized conditions, the diblock and triblock copolymers could be synthesized with good control over molecular weight and dispersities around 1.1 were obtained.
Effect of Bamboo Flour Grafted Lactide on the Interfacial Compatibility of Polylactic Acid/Bamboo Flour Composites
Authors: Song Xin-yu , Wang Meng , Weng Yun-xuan , Huang Zhi-gang
Published: August 2017

Bamboo flour (BF) was grafted onto lactide (LA) in the molten state using stannous octoate as a catalyst to form BF-g-LA. Then, polylactic acid (PLA) was blended with BF (PLA/BF, 85/15 wt %) to prepare PLA/BF/BF-g-LA composites using BF-g-LA as a compatibilizer. The grafting rate of BF was characterized using infrared testing and elemental analysis. To investigate the effect of BF-g-LA on the performance of PLA/BF/BF-g-LA composites, the phase morphology, thermal stability, and mechanical properties of the composites were characterized using scanning electron microscopy, thermogravimetric analysis, and universal material testing, respectively. The addition of BF-g-LA improved the interface compatibility between PLA and BF. When the BF-g-LA content was 2 phr, the tensile and impact strengths of PLA/BF/BF-g-LA composites were 55.3 MPa and 9.56 kJ/m2, representing 30% and 27% increases, respectively, relative to corresponding values for PLA/BF composites.
A Simple Normalized Difference Approach to Burnt Area Mapping Using Multi-Polarisation C-Band SAR
Authors: Engelbrecht Jeanine , Theron Andre , Vhengani Lufuno , Kemp Jaco
Published: August 2017

In fire-prone ecosystems, periodic fires are vital for ecosystem functioning. Fire managers seek to promote the optimal fire regime by managing fire season and frequency requiring detailed information on the extent and date of previous burns. This paper investigates a Normalised Difference α-Angle (NDαI) approach to burn-scar mapping using C-band data. Polarimetric decompositions are used to derive α-angles from pre-burn and post-burn scenes and NDαI is calculated to identify decreases in vegetation between the scenes. The technique was tested in an area affected by a wildfire in January 2016 in the Western Cape, South Africa. The quad-pol H-A-α decomposition was applied to RADARSAT-2 data and the dual-pol H-α decomposition was applied to Sentinel-1A data. The NDαI results were compared to a burn scar extracted from Sentinel-2A data. High overall accuracies of 97.4% (Kappa = 0.72) and 94.8% (Kappa = 0.57) were obtained for RADARSAT-2 and Sentinel-1A, respectively. However, large omission errors were found and correlated strongly with areas of high local incidence angle for both datasets. The combined use of data from different orbits will likely reduce these errors. Furthermore, commission errors were observed, most notably on Sentinel-1A results. These errors may be due to the inability of the dual-pol H-α decomposition to effectively distinguish between scattering mechanisms. Despite these errors, the results revealed that burnt areas could be extracted and were in good agreement with the results from Sentinel-2A. Therefore, the approach can be considered in areas where persistent cloud cover or smoke prevents the extraction of burnt area information using conventional multispectral approaches.
Impact Analysis of Climate Change on Snow over a Complex Mountainous Region Using Weather Research and Forecast Model (WRF) Simulation and Moderate Resolution Imaging Spectroradiometer Data (MODIS)-Terra Fractional Snow Cover Products
Authors: Pan Xiaoduo , Li Xin , Cheng Guodong , Chen Rensheng , Hsu Kuolin
Published: August 2017

Climate change has a complex effect on snow at the regional scale. The change in snow patterns under climate change remains unknown for certain regions. Here, we used high spatiotemporal resolution snow-related variables simulated by a weather research and forecast model (WRF) including snowfall, snow water equivalent and snow depth along with fractional snow cover (FSC) data extracted from Moderate Resolution Imaging Spectroradiometer Data (MODIS)-Terra to evaluate the effects of climate change on snow over the Heihe River Basin (HRB), a typical inland river basin in arid northwestern China from 2000 to 2013. We utilized Empirical Orthogonal Function (EOF) analysis and Mann-Kendall/Theil-Sen trend analysis to evaluate the results. The results are as follows: (1) FSC, snow water equivalent, and snow depth across the entire HRB region decreased, especially at elevations over 4500 m; however, snowfall increased at mid-altitude ranges in the upstream area of the HRB. (2) Total snowfall also increased in the upstream area of the HRB; however, the number of snowfall days decreased. Therefore, the number of extreme snow events in the upstream area of the HRB may have increased. (3) Snowfall over the downstream area of the HRB decreased. Thus, ground stations, WRF simulations and remote sensing products can be used to effectively explore the effect of climate change on snow at the watershed scale.
An Improved Spectrum Model for Sea Surface Radar Backscattering at L-Band
Authors: Du Yanlei , Yang Xiaofeng , Chen Kun-Shan , Ma Wentao , Li Ziwei
Published: August 2017

L-band active microwave remote sensing is one of the most important technical methods of ocean environmental monitoring and dynamic parameter retrieval. Recently, a unique negative upwind-crosswind (NUC) asymmetry of L-band ocean backscatter over a low wind speed range was observed. To study the directional features of L-band ocean surface backscattering, a new directional spectrum model is proposed and built into the advanced integral equation method (AIEM). This spectrum combines Apel’s omnidirectional spectrum and an improved empirical angular spreading function (ASF). The coefficients in the ASF were determined by the fitting of radar observations so that it provides a better description of wave directionality, especially over wavenumber ranges from short-gravity waves to capillary waves. Based on the improved spectrum and the AIEM scattering model, L-band NUC asymmetry at low wind speeds and positive upwind-crosswind (PUC) asymmetry at higher wind speeds are simulated successfully. The model outputs are validated against Aquarius/SAC-D observations under different incidence angles, azimuth angles and wind speed conditions.
A New Urban Index for Expressing Inner-City Patterns Based on MODIS LST and EVI Regulated DMSP/OLS NTL
Authors: Liu Yangxiaoyue , Yang Yaping , Jing Wenlong , Yao Ling , Yue Xiafang , Zhao Xiaodan
Published: August 2017

With the rapid pace of urban expansion, comprehensively understanding urban spatial patterns, built environments, green-spaces distributions, demographic distributions, and economic activities becomes more meaningful. Night Time Lights (NTL) images acquired through the Operational Linescan System of the US Defense Meteorological Satellite Program (DMSP/OLS NTL) have long been utilized to monitor urban areas and their expansion characteristics since this system detects variation in NTL emissions. However, the pixel saturation phenomenon leads to a serious limitation in mapping luminance variations in urban zones with nighttime illumination levels that approach or exceed the pixel saturation limits of OLS sensors. Consequently, we propose an NTL-based city index that utilizes the Moderate-resolution Imaging Spectroradiometer (MODIS) Land Surface Temperature (LST) and Enhanced Vegetation Index (EVI) images to regulate and compensate for desaturation on NTL images acquired from corresponding urban areas. The regulated results achieve good performance in differentiating central business districts (CBDs), airports, and urban green spaces. Consequently, these derived imageries could effectively convey the structural details of urban cores. In addition, compared with the Vegetation Adjusted NTL Urban Index (VANUI), LST-and-EVI-regulated-NTL-city index (LERNCI) reveals superior capability in delineating the spatial structures of selected metropolis areas across the world, especially in the large cities of developing countries. The currently available results indicate that LERNCI corresponds better to city spatial patterns. Moreover, LERNCI displays a remarkably better “goodness-of-fit” correspondence with both the Version 1 Nighttime Visible Infrared Imaging Radiometer Suite Day/Night Band Composite (NPP/VIIRS DNB) data and the WorldPop population-density data compared with the VANUI imageries. Thus, LERNCI can act as a helpful indicator for differentiating and classifying regional economic activities, population aggregations, and energy-consumption and city-expansion patterns. LERNCI can also serve as a valuable auxiliary reference for decision-making processes that concern subjects such as urban planning and easing the central functions of metropolis.
Synergistic Use of Remote Sensing and Modeling to Assess an Anomalously High Chlorophyll-a Event during Summer 2015 in the South Central Red Sea
Authors: Li Wenzhao , El-Askary Hesham , ManiKandan K. , Qurban Mohamed , Garay Michael , Kalashnikova Olga
Published: August 2017

An anomalously high chlorophyll-a (Chl-a) event (>2 mg/m3) during June 2015 in the South Central Red Sea (17.5° to 22°N, 37° to 42°E) was observed using Moderate Resolution Imaging Spectroradiometer (MODIS) data from the Terra and Aqua satellite platforms. This differs from the low Chl-a values (<0.5 mg/m3) usually encountered over the same region during summertime. To assess this anomaly and possible causes, we used a wide range of oceanographical and meteorological datasets, including Chl-a concentrations, sea surface temperature (SST), sea surface height (SSH), mixed layer depth (MLD), ocean current velocity and aerosol optical depth (AOD) obtained from different sensors and models. Findings confirmed this anomalous behavior in the spatial domain using Hovmöller data analysis techniques, while a time series analysis addressed monthly and daily variability. Our analysis suggests that a combination of factors controlling nutrient supply contributed to the anomalous phytoplankton growth. These factors include horizontal transfer of upwelling water through eddy circulation and possible mineral fertilization from atmospheric dust deposition. Coral reefs might have provided extra nutrient supply, yet this is out of the scope of our analysis. We thought that dust deposition from a coastal dust jet event in late June, coinciding with the phytoplankton blooms in the area under investigation, might have also contributed as shown by our AOD findings. However, a lag cross correlation showed a two- month lag between strong dust outbreak and the high Chl-a anomaly. The high Chl-a concentration at the edge of the eddy emphasizes the importance of horizontal advection in fertilizing oligotrophic (nutrient poor) Red Sea waters.
Estimating Daily Reference Evapotranspiration in a Semi-Arid Region Using Remote Sensing Data
Authors: Najmaddin Peshawa M. , Whelan Mick J. , Balzter Heiko
Published: August 2017

Estimating daily evapotranspiration is challenging when ground observation data are not available or scarce. Remote sensing can be used to estimate the meteorological data necessary for calculating reference evapotranspiration ETₒ. Here, we assessed the accuracy of daily ETₒ estimates derived from remote sensing (ETₒ-RS) compared with those derived from four ground-based stations (ETₒ-G) in Kurdistan (Iraq) over the period 2010–2014. Near surface air temperature, relative humidity and cloud cover fraction were derived from the Atmospheric Infrared Sounder/Advanced Microwave Sounding Unit (AIRS/AMSU), and wind speed at 10 m height from MERRA (Modern-Era Retrospective Analysis for Research and Application). Four methods were used to estimate ETₒ: Hargreaves–Samani (HS), Jensen–Haise (JH), McGuinness–Bordne (MB) and the FAO Penman Monteith equation (PM). ETₒ-G (PM) was adopted as the main benchmark. HS underestimated ETₒ by 2%–3% (R2 = 0.86 to 0.90; RMSE = 0.95 to 1.2 mm day−1 at different stations). JH and MB overestimated ETₒ by 8% to 40% (R2= 0.85 to 0.92; RMSE from 1.18 to 2.18 mm day−1). The annual average values of ETₒ estimated using RS data and ground-based data were similar to one another reflecting low bias in daily estimates. They ranged between 1153 and 1893 mm year−1 for ETₒ-G and between 1176 and 1859 mm year−1 for ETₒ-RS for the different stations. Our results suggest that ETₒ-RS (HS) can yield accurate and unbiased ETₒ estimates for semi-arid regions which can be usefully employed in water resources management.
Reconstructing Satellite-Based Monthly Precipitation over Northeast China Using Machine Learning Algorithms
Authors: Jing Wenlong , Zhang Pengyan , Jiang Hao , Zhao Xiaodan
Published: August 2017

Attaining accurate precipitation data is critical to understanding land surface processes and global climate change. The development of satellite sensors and remote sensing technology has resulted in multi-source precipitation datasets that provide reliable estimates of precipitation over un-gauged areas. However, gaps exist over high latitude areas due to the limited spatial extent of several satellite-based precipitation products. In this study, we propose an approach for the reconstruction of the Tropical Rainfall Measuring Mission (TRMM) 3B43 monthly precipitation data over Northeast China based on the interaction between precipitation and surface environment. Two machine learning algorithms, support vector machine (SVM) and random forests (RF), are implemented to detect possible relationships between precipitation and normalized difference vegetation index (NDVI), land surface temperature (LST), and digital elevation model (DEM). The relationships between precipitation and geographical location variations based on longitude and latitude are also considered in the reconstruction model. The reconstruction of monthly precipitation in the study area is conducted in two spatial resolutions (25 km and 1 km). The validation is performed using in-situ observations from eight meteorological stations within the study area. The results show that the RF algorithm is robust and not sensitive to the choice of parameters, while the training accuracy of the SVM algorithm has relatively large fluctuations depending on the parameter settings and month. The precipitation data reconstructed with RF show strong correlation with in situ observations at each station and are more accurate than that obtained using the SVM algorithm. In general, the accuracy of the estimated precipitation at 1 km resolution is slightly lower than that of data at 25 km resolution. The estimation errors are positively related to the average precipitation.
Discriminative Feature Metric Learning in the Affinity Propagation Model for Band Selection in Hyperspectral Images
Authors: Yang Chen , Tan Yulei , Bruzzone Lorenzo , Lu Laijun , Guan Renchu
Published: August 2017

Traditional supervised band selection (BS) methods mainly consider reducing the spectral redundancy to improve hyperspectral imagery (HSI) classification with class labels and pairwise constraints. A key observation is that pixels spatially close to each other in HSI have probably the same signature, while pixels further away from each other in the space have a high probability of belonging to different classes. In this paper, we propose a novel discriminative feature metric-based affinity propagation (DFM-AP) technique where the spectral and the spatial relationships among pixels are constructed by a new type of discriminative constraint. This discriminative constraint involves chunklet and discriminative information, which are introduced into the BS process. The chunklet information allows for grouping of spectrally-close and spatially-close pixels together without requiring explicit knowledge of their class labels, while discriminative information provides important separability information. A discriminative feature metric (DFM) is proposed with the discriminative constraints modeled in terms of an optimal criterion for identifying an efficient distance metric learning method, which involves discriminative component analysis (DCA). Following this, the representative subset of bands can be identified by means of an exemplar-based clustering algorithm, which is also known as the process of affinity propagation. Experimental results show that the proposed approach yields a better performance in comparison with several representative class label and pairwise constraint-based BS algorithms. The proposed DFM-AP improves the classification performance with discriminative constraints by selecting highly discriminative bands with low redundancy.