bluuebunny/crossref_metadata_2025 huggingface dataset:
Gender-Dependent Bimanual Task Performance
Authors: Mickevičienė Dalia , Motiejūnaitė Kristina , Karanauskienė Diana , Skurvydas Albertas , Vizbaraitė Daiva , Krutulytė Gražina , Rimdeikienė Inesa
Published: May 2018

Background and Objective. Many studies have suggested that each hand has a different special talent; however, there is a lack of data in the area of goal-directed bimanual hand coordination and its dependence on gender. The aim of this paper was to investigate gender-dependent bimanual speed-accuracy task performance. Material and Methods. Twelve healthy young males and twelve healthy young females (all righthanded) performed protractile movements with both arms simultaneously by pushing joysticks toward two targets as quickly and accurately as possible. Results. Though no significant difference was observed in the reaction time during a unimanual speed-accuracy task between the left and right hands as well as men and women, during a bimanual task, the reaction time of both the hands was significantly longer in women than men. There was no significant difference in the velocity of both the hands during a bimanual speed-accuracy task between men and women, while the accuracy of the left hand was significantly greater in men than women. There was no significant difference in intraindividual variability in the reaction time, maximal velocity, and path of movement between men and women as well as the left and right hands, but variability in the average velocity of the right hand both in women and men was significantly greater compared with their left hand. Conclusions. Whereas people typically look at the target location for a reaching movement, it is possible that two objects are simultaneously fixated.
Human Herpesvirus 6 and 7 Reactivation and Disease Activity in Multiple Sclerosis
Authors: Nora-Krukle Zaiga , Chapenko Svetlana , Logina Inara , Millers Andrejs , Platkajis Ardis , Murovska Modra
Published: May 2018

Recent studies have focused on the associations between human herpesvirus 6 (HHV-6) and human herpesvirus 7 (HHV-7), and multiple sclerosis (MS). The aim of this study was to investigate the associations between HHV-6 and HHV-7 reactivation and MS disease activity, and interleukin 12 (IL-12) and tumor necrosis factor α (TNF-α) production. Material and Methods. The frequency of plasma viremia by nested polymerase chain reaction and transcription of viral mRNA in peripheral blood mononuclear cells by reverse transcriptasepolymerase chain reaction (RT-PCR) of 14 relapsing/remitting (RR) and 14 secondary progressive (SP) MS patients were studied in comparison with clinical manifestation of the disease. Serum concentrations of cytokines IL-12 and TNF-α were analyzed by enzyme-linked immunosorbent assay. Results. Plasma samples from 25 of the 28 MS patients with estimated latent/persistent HHV-6 and/or HHV-7 infection were examined during relapse and remission/relative remission. HHV-6 reactivation was found in 4 of the 7 RRMS and 4 of the 7 SPMS patients, and HHV-7 reactivation was identified in 3 of the 7 RRMS and 1 of the 7 SPMS patients (all in relapse). In 2 of the 3 RRMS patients without viremia in relapse, HHV-6 mRNA transcription was detected. In RRMS and SPMS patients with active HHV-6 and HHV-7 infection in relapse, the serum concentrations of IL-12 and TNF-α were significantly higher than in those with latent virus infection. Conclusions. HHV-6 and HHV-7 reactivation could be implicated in the exacerbation of MS via activation of Th1 lymphocyte subsets.
The Prevalence of Viral Hepatitis C in Latvia: A Population-Based Study
Authors: Tolmane Ieva , Rozentale Baiba , Keiss Jazeps , Arsa Frida , Brigis Girts , Zvaigzne Aivars
Published: May 2018

Background and Objective. Chronic viral hepatitis C (VHC) is one of the most discussed infectious diseases worldwide. The number of infected persons worldwide is approximately 170 million, and in Europe, it exceeds 9 million. The aim of this study was to determine the prevalence of antibodies to hepatitis C virus (anti- HCV prevalence) and prevalence of HCV viremia (HCV-RNA prevalence) in Latvia. Material and Methods. A multistage randomized selection was used. A total of 42 primary care physicians (PCPs) were randomly selected from the register of PCPs from different regions of Latvia. From each PCP register, 60 subjects were selected (1651 individuals in total) and invited for the anti-HCV test with a screening method (ELISA). In case of positive results, antibodies were confirmed by the Western blot test, and all these subjects were tested for HCV-RNA by polymerase chain reaction. Results. Of the 1459 subjects tested, 57 were positive for anti-HCV (3.9%; 95% CI 3% to 5%); 35 of them were positive for anti-HCV with a confirmatory test (2.4%; 95% CI, 1.7% to 3.3%): 19 men and 16 women (3.8% and 1.7%, respectively; P=0.011). The results of HCV RNA test were positive in 25 subjects (1.7%; 95% CI, 1.2% to 2.5%): 15 men and 10 women (3% and 1% respectively, P=0.019). Conclusions. The prevalence of anti-HCV and HCV-RNA in Latvia was found to be 2.4% and 1.7%, respectively. The prevalence of anti-HCV and HCV-RNA was higher in men than women.
Mildronate as a Regulator of Protein Expression in a Rat Model of Parkinson’s Disease
Authors: Isajevs Sergejs , Isajeva Darja , Beitnere Ulrika , Jansone Baiba , Kalvinsh Ivars , Klusa Vija
Published: May 2018

Background. Mildronate (3-[2,2,2-trimethylhydrazinium] propionate dihydrate) traditionally is a well-known cardioprotective drug. However, our recent studies convincingly demonstrated its neuroprotective properties. The aim of the present study was to evaluate the influence of mildronate on the expression of proteins that are involved in the differentiation and survival of the nigrostriatal dopaminergic neurons in the rat model of Parkinson’s disease (PD). The following biomarkers were used: heat shock protein 70 (Hsp70, a molecular chaperone), glial cell line-derived nerve growth factor (GDNF, a growth factor promoting neuronal differentiation, regeneration, and survival), and neural cell adhesion molecule (NCAM). Material and Methods. PD was modeled by 6-hydroxydopamine (6-OHDA) unilateral intrastriatal injection in rats. Mildronate was administered at doses of 10, 20, and 50 mg/kg for 2 weeks intraperitoneally before 6-OHDA injection. Rat brains were dissected on day 28 after discontinuation of mildronate injections. The expression of biomarkers was assessed immunohistochemically and by Western blot assay. Results. 6-OHDA decreased the expression of Hsp70 and GDNF in the lesioned striatum and substantia nigra, whereas in mildronate-pretreated (20 and 50 mg/kg) rats, the expression of Hsp70 and GDNF was close to the control group values. NCAM expression also was decreased by 6-OHDA in the striatum and it was totally protected by mildronate at a dose of 50 mg/kg. In contrast, in the substantia nigra, 6-OHDA increased the expression of NCAM, while mildronate pretreatment (20 and 50 mg/kg) reversed the 6-OHDA-induced overexpression of NCAM close to the control values. Conclusion. The obtained data showed that mildronate was capable to regulate the expression of proteins that play a role in the homeostasis of neuro-glial processes.
An In Vitro and In Vivo Study on the Intensity of Adhesion and Colonization by Staphylococcus epidermidis and Pseudomonas aeruginosa on Originally Synthesized Biomaterials With Different Chemical Composition and Modified Surfaces and Their Effect on Expression of TNF-α, β-Defensin 2 and IL-10 in Tissues
Authors: Reinis Aigars , Pilmane Māra , Stunda Agnese , Vētra Jānis , Kroiča Juta , Rostoka Dagnija , Šalms Ģirts , Vostroilovs Antons , Dons Aleksejs , Bērziņa-Cimdiņa Līga
Published: May 2018

The aim of this study was to determine adhesion and colonization of bacteria on the surface of originally synthesized glass-ceramic biomaterials and their effect on inflammation reactions in tissues surrounding the implant. Materials and Methods. Biomaterial discs were contaminated with bacterial suspensions of 10, 102, and 103 colony forming units (CFU)/mL (P. aeruginosa ATCC 27853 and S. epidermidis ATCC 12228), and after 2 hours of cultivation, the intensity of bacterial adhesion was determined. For in vivo tests, the samples were contaminated with 102 and 103 CFU/mL cultivated at 37oC for 2 h to ensure bacterial adhesion. Contaminated biomaterial samples were implanted in the interscapular area of chinchilla rabbits for 2 and 4 weeks. The biomaterials were removed, and using plate count and sonification methods, bacterial colonization on the surface of biomaterials was determined. Moreover, the expression of TNF-α, β-defensin 2, and IL-10 in the surrounding tissues was assessed by using immunohistochemistry methods. Results. P. aeruginosa more intensively colonized biomaterials in the in vivo study as compared with S. epidermidis. Il-10 is a regulatory cytokine, which reduces the intensity of inflammatory cell activity, thus reducing nonspecific resistance of the organism. Conclusions. The expression of TNF-α and IL-10 was not affected by short (2 and 4 weeks) biomaterial implantation. Pronounced cytokine expression in tissues around implanted biomaterials contaminated with P. aeruginosa was observed.
Large Omental Metastases of a Gastrointestinal Stromal Tumor
Authors: Ignatavičius Povilas , Petraitis Tomas , Saladžinskas Žilvinas , Butkevičienė Lilija , Žvinienė Kristina
Published: May 2018

Gastrointestinal stromal tumors are rare tumors, originating from the interstitial cells of Cajal. They are the most common mesenchymal tumors of the gastrointestinal tract. Metastatic tumor is treated with imatinib mesylate. A case of large metastases of a gastrointestinal stromal tumor to the omentum, diagnosis and treatment principles are presented in this case report.
Pregnancy-Related Aortic Aneurysm and Dissection in Patients With Marfan’s Syndrome: Medical and Surgical Management During Pregnancy and After Delivery
Authors: Vranes Mile , Velinovic Milos , Kovacevic-Kostic Natasa , Savic Dragutin , Nikolic Dejan , Karan Radmila
Published: May 2018

In the current article, 3 cases of aortic aneurysm and dissection in pregnant patients with Marfan’s syndrome are reported. It is well known that pregnancy is a risk factor for the development of aortic aneurysm and dissection in women with Marfan’s syndrome since it is shown that dissection can develop both before and after labor. Marfan patients with an aortic root diameter greater than 4 cm should undergo preconceptual counseling for surgical aortic repair before pregnancy. Pregnant Marfan patients with an aortic aneurysm should be closely and continuously evaluated by multidisciplinary specialists in order to prevent possible aortic dissection that could be fatal for both the mother and the fetus.
Microflora of the Oral Cavity in Patients with Xerostomia
Authors: Guobis Žygimantas , Kareivienė Violeta , Basevičienė Nomeda , Paipalienė Pajauta , Niedzelskienė Irena , Sabalys Gintautas , Kubilius Ričardas , Gervickas Albinas
Published: May 2018

Objective. The aim of this study was to evaluate the dependence of the condition of the microflora of the oral cavity on the etiology of xerostomia, patients’ sex, age, degree of hyposalivation, and duration of the sense of dryness. Material and Methods. A total of 64 patients with complaints of oral dryness referred to the Clinic of Oral and Dental Diseases, Hospital of Lithuanian University of Health Sciences, for consultation during the period from 2003 to 2005 were selected for the study. The etiological factors of xerostomia were as follows: radiotherapy (PRT) to the maxillofacial area, Sjögren’s syndrome (SS), and xerogenic medications, tricyclic antidepressants (TCAs). Results. There were 50 women and 14 men. Their mean age was 60.5±1.6 years. All the patients in the PRT group had high counts of Candida spp. as compared with percentages of patients in the TCA and SS groups (100% vs. 66.7% and 56.2%, P<0.05). Patients’ age and sex in different etiology groups had no significant impact on the condition of their oral microflora. There were equal percentages of patients with deficient and normal salivation in the TCA group (44% in both the groups; P<0.01). All the patients in the PRT group had pronounced hyposalivation (P<0.002). A significantly greater percentage of patients with severely reduced salivation had high counts of Lactobacillus spp. (P<0.01). Significantly greater percentages of patients with the clinical duration of xerostomia of up to 6 months had high counts of Lactobacillus spp. and Candida spp. colonies. Conclusions. In patients with xerostomia, the condition of the microflora of the oral cavity and impairment of major salivary gland function varied according to the etiology of the disease. The level of hyposalivation and the duration of xerostomia were found to have a significant impact on the microflora of the oral cavity.
Characteristics of Carbapenem-Resistant Pseudomonas aeruginosa Strains in Patients with Ventilator-Associated Pneumonia in Intensive Care Units
Authors: Vitkauskienė Astra , Skrodenienė Erika , Dambrauskienė Asta , Bakšytė Giedrė , Macas Andrius , Sakalauskas Raimundas
Published: May 2018

The aim of this study was to determine the characteristics of carbapenem-resistant Pseudomonas aeruginosa (P. aeruginosa) strains and 5-year changes in resistance in a tertiary university hospital. Material and Methods. The study included 90 and 101 randomly selected P. aeruginosa strains serotyped in 2003 and 2008, respectively. The standardized disk diffusion test and E-test were used to determine resistance to antibiotics. P. aeruginosa strains were considered to have high-level resistance if a minimum inhibitory concentration (MIC) for imipenem or meropenem was >32 μg/mL. To identify serogroups, sera containing specific antibodies against O group antigens of P. aeruginosa were used. P. aeruginosa isolates resistant to imipenem or/and meropenem were screened for metallo-β-lactamase (MBL) production by using the MBL E-test. Results. Comparison of the changes in resistance of P. aeruginosa strains to carbapenems within the 5-year period revealed that the level of resistance to imipenem increased. In 2003, 53.3% of P. aeruginosa strains were found to be highly resistant to imipenem, while in 2008, this percentage increased to 87.8% (P=0.01). The prevalence of MBL-producing strains increased from 15.8% in 2003 to 61.9% in 2008 (P<0.001). In 2003 and 2008, carbapenem-resistant P. aeruginosa strains were more often resistant to ciprofloxacin and gentamicin than carbapenem-sensitive strains. In 2008, carbapenem- resistant strains additionally were more often resistant to ceftazidime, cefepime, aztreonam, piperacillin, and amikacin than carbapenem-sensitive strains. MBL-producing P. aeruginosa strains belonged more often to the O:11 serogroup than MBL-non-producing strains (51.7% vs. 34.3%, P<0.05). A greater percentage of non-MBL-producing strains had low MICs against ciprofloxacin and amikacin as compared with MBL-producing strains. Conclusions. The results of our study emphasize the need to restrict the spread of O:11 serogroup P. aeruginosa strains and usage of carbapenems to treat infections with P. aeruginosa in the intensive care units of our hospital
The Relationship Between Seropositivity Against Chlamydia pneumoniae and Stroke and its Subtypes in a Latvian Population
Authors: Ķēniņa Viktorija , Auce Pauls , Priede Zanda , Millers Andrejs
Published: May 2018

Background and Objective. Serological evidence of infection with Chlamydia pneumoniae has been associated with cardiovascular diseases, but the relationship with stroke and its risk factors remains not completely understood. The aim of this study was to determine whether serological evidence of infection with Chlamydia pneumoniae was associated with the risk of ischemic stroke and any of investigated stroke subtypes. Material and Methods. Confirmed stroke cases (n=102) were compared with gender- and agematched control patients (n=48). The patients with stroke were divided into 3 groups according to the TOAST criteria: atherothrombotic (n=36), cardioembolic (n=47), and of undetermined etiology (n=19). Plasma levels of IgG antibodies to Chlamydia pneumoniae were measured by enzymelinked immunosorbent assay. Results. There was a significant association between seropositivity to Chlamydia pneumoniae and stroke. Anti-Chlamydia pneumoniae IgG antibodies were detected in 64 case patients (62.7%) and 17 control patients (35.4%) (χ2=9.8; df=1; P=0.002). IgG seropositivity to Chlamydia pneumoniae was linked to all the analyzed etiological subtypes of stroke. Conclusion. This study showed that IgG seropositivity to Chlamydia pneumoniae was associated with stroke and all the analyzed etiological subtypes of stroke.
A Population-Based Surveillance Study on the Epidemiology of Hepatitis C in Estonia
Authors: Mansberg Kairi , Kull Karin , Salupere Riina , Prükk Tiina , Margus Benno , Kariis Toomas , Remmel Triin , Suurmaa Külliki , Ott Kristi , Jaago Krista , Šmidt Jelena
Published: May 2018

Background and objective: The hepatitis C virus (HCV)-infected patients serve as a reservoir for transmission of the disease to others and are at risk of developing chronic hepatitis C, cirrhosis, and hepatocellular carcinoma. Although the epidemiological data of high rate HCV infection have been obtained in many countries, such data are insufficient in Estonia. Therefore, the aim of the study was to analyze country-specific data on HCV patients. Materials and methods: Data about age, gender, diagnosis, possible risk factors, coinfections, HCV genotypes, liver fibrosis stages and extrahepatic manifestations were collected from 518 patients. Results: The most common risk factors for hepatitis C were injection drug use and tattooing in the 30–39 and 40–49 year age groups, and blood transfusion in the 50–59 and 60–69 year age groups. The other risk factors established were profession-related factors and sexual contact. The prevailing viral genotype among the HCV infected patients was genotype 1 (69% of the patients) followed by genotype 3 (25%). Genotypes 1 and 3 correlated with blood transfusions before 1994, drug injections and tattooing. Conclusions: Our study provides the best representation of genotype distribution across Estonia. As a result of the study, valuable data has been collected on hepatitis C patients in Estonia.
Smoking-Attributable Direct Healthcare Expenditure in Lithuania: A Prevalence-Based Annual Cost Approach
Authors: Liutkutė Vaida , Štelemėkas Mindaugas , Veryga Aurelijus
Published: May 2018

Introduction: The estimates of the economic burden of smoking provide the basis for a comprehensive assessment of the overall economic impact and evidence for potential public health policy intervention by the government. The aim of this paper is to estimate the smoking-attributable direct healthcare expenditure covered by the Compulsory Health Insurance Fund (CHIF) in Lithuania in 2013. Methods: A prevalence-based and disease-specific annual cost approach was applied to 25 smoking-related diseases or disease categories. Our analysis included only direct government healthcare expenditure (reimbursed by CHIF), including: smoking-attributable outpatient and inpatient care services, medical rehabilitation, reimbursable and publicly procured pharmaceuticals and medical aids, the emergency medical aid (ambulance) service, nursing, and expensive tests and procedures. The smoking-attributable expenditure on the above-mentioned healthcare services was calculated by multiplying the total annual expenditure by the corresponding smoking attributable fractions (SAFs). Results: The total smoking-attributable government expenditure amounted to €37.4 million in 2013. This represented 3% of the total CHIF budget in 2013. Smoking-attributable expenditure on inpatient care and medical rehabilitation services was two times higher for male smokers, than for female smokers. Conclusions: Smoking imposes a significant preventable financial cost within the budget of the Lithuanian healthcare system. A quantitative estimation of smoking related healthcare costs could provide an incentive for the development of smoking cessation services, with additional attention towards male smokers, as well as an important focus on smoking prevention among children and youths.
Comparison of the Effects of Subconjunctival Injections of Bevacizumab and Interferon Alpha-2a on Corneal Angiogenesis in a Rat Model
Authors: Bilgin Sinan
Published: May 2018

Background and objective: Corneal neovascularization (CNV) is a vision-threatening condition arising from various corneal diseases. The aim of this study is to compare the effectiveness of bevacizumab and interferon alpha-2a (IFNα-2a) treatment on corneal neovascularization. Materials and Methods: Twenty-four Wistar albino rats were used in this study. After cauterization of the cornea with a silver nitrate applicator stick, the control group received 0.1 mL saline solution, the second group received 0.1 mL IFNα-2a (IFNα-2a, 6 million international units [MIU]/0.5 mL), and the third group received 2.5 mg bevacizumab by subconjunctival injection. An additional injection was administered to each group on the fourth day. After one week, the corneal neovascularization rate and the longest neovascular sprout length were determined. Results: The neovascularization rate (saline 0.65 ± 0.05; IFNα-2a 0.62 ± 0.07; bevacizumab 0.42 ± 0.11) with bevacizumab was significantly lower, more than those with IFNα-2a and saline (p < 0.001 and p < 0.001). The longest neovascular sprout length (saline, 4.00 ± 0.6 mm; IFNα-2a, 3.63 ± 0.52 mm; bevacizumab, 2.81 ± 0.65 mm) with bevacizumab was significantly shorter than those with saline and IFNα-2a (p = 0.001 and p = 0.012). Conclusions: Subconjunctival IFNα-2a has limited efficacy in the treatment of corneal neovascularization.
Investigation of the Use of a Bio-Derived Solvent for Non-Solvent-Induced Phase Separation (NIPS) Fabrication of Polysulfone Membranes
Authors: Dong Xiaobo , Al-Jumaily Amna , Escobar Isabel
Published: May 2018

Organic solvents, such as N-methyl-2-pyrrolidone (NMP) and dimethylacetamide (DMAc), have been traditionally used to fabricate polymeric membranes. These solvents may have a negative impact on the environment and human health; therefore, using renewable solvents derived from biomass is of great interest to make membrane fabrication sustainable. Methyl-5-(dimethylamino)-2-methyl-5-oxopentanoate (Rhodiasolv PolarClean) is a bio-derived, biodegradable, nonflammable and nonvolatile solvent. Polysulfone is a commonly used polymer to fabricate membranes due to its thermal stability, strong mechanical strength and good chemical resistance. From cloud point curves, PolarClean showed potential to be a solvent for polysulfone. Membranes prepared with PolarClean were investigated in terms of their morphology, porosity, water permeability and protein rejection, and were compared to membranes prepared with traditional solvents. The pores of polysulfone/PolarClean membranes were sponge-like, and the membranes displayed higher water flux values (176.0 ± 8.8 LMH) along with slightly higher solute rejection (99.0 ± 0.51%). On the other hand, PSf/DMAc membrane pores were finger-like with lower water flux (63.1 ± 12.4 LMH) and slightly lower solute rejection (96 ± 2.00%) when compared to PSf/PolarClean membranes.
Influence of Intermetallic Particles on the Corrosion Properties of Extruded ZK60 Mg Alloy Containing Cu
Authors: Baek Soo-Min , Kim Beomcheol , Park Sung Soo
Published: May 2018

The microstructure and corrosion behavior of the extruded ZK60 Mg alloys with different Cu content were comparatively investigated. The ZK60 alloy had a microstructure consisting of α-Mg grains with intermetallic MgZn2 and Zn2Zr3 particles. The addition of 1 wt % Cu resulted in the additional presence of CuMgZn particles. In a 0.6 M NaCl solution at 25 °C, the corrosion rate of the alloy with the added Cu appeared to be about 16% faster than that of the alloy without the addition of Cu. The factors affecting the degraded corrosion resistance of the Cu-added ZK60 alloy are discussed.
Numerically Based Phase Transformation Maps for Dissimilar Aluminum Alloys Joined by Friction Stir-Welding
Authors: Hamilton Carter , Dymek Stanisław , Kopyściański Mateusz , Węglowska Aleksandra , Pietras Adam
Published: May 2018

Sheets of aluminum 2017A-T451 and 7075-T651 were friction stir-welded in a butt-weld configuration. An existing computational model of the welding process for temperature distribution and material flow was adapted to estimate the phase transformations that occur across the weld zone. Near the weld center, process temperatures are sufficient to fully dissolve the equilibrium η phase in 7075 and partially dissolve the equilibrium S phase in 2017A. Upon cooling, Guinier–Preston (GP) and Guinier–Preston–Bagaryatsky (GPB) zones re-precipitate, and hardness recovers. Due to the more complete dissolution of the equilibrium phase in 7075, the hardness recovery skews toward whichever side of the weld, i.e., the advancing or retreating side, represents the 7075 workpiece. Phase transformation maps generated by the numerical simulation align not only with the hardness profiles taken across the weld zone, but also with positron lifetimes obtained through positron annihilation lifetime spectroscopy (PALS). Boundaries between the aluminum matrix and the secondary phases provide open volumes to trap positrons; therefore, positron lifetimes across the weld correspond with the phase transformations that occur in 7075 and 2017A during processing.
Features in Microfluidic Paper-Based Devices Made by Laser Cutting: How Small Can They Be?
Authors: Mahmud Md. Almostasim , Blondeel Eric J. M. , Kaddoura Moufeed , MacDonald Brendan D.
Published: May 2018

In this paper, we determine the smallest feature size that enables fluid flow in microfluidic paper-based analytical devices (µPADs) fabricated by laser cutting. The smallest feature sizes fabricated from five commercially available paper types: Whatman filter paper grade 50 (FP-50), Whatman 3MM Chr chromatography paper (3MM Chr), Whatman 1 Chr chromatography paper (1 Chr), Whatman regenerated cellulose membrane 55 (RC-55) and Amershan Protran 0.45 nitrocellulose membrane (NC), were 139 ± 8 µm, 130 ± 11 µm, 103 ± 12 µm, 45 ± 6 µm, and 24 ± 3 µm, respectively, as determined experimentally by successful fluid flow. We found that the fiber width of the paper correlates with the smallest feature size that has the capacity for fluid flow. We also investigated the flow speed of Allura red dye solution through small-scale channels fabricated from different paper types. We found that the flow speed is significantly slower through microscale features and confirmed the similar trends that were reported previously for millimeter-scale channels, namely that wider channels enable quicker flow speed.
Surface Modification of Electroosmotic Silicon Microchannel Using Thermal Dry Oxidation
Authors: Tuan Yaakub Tuan Norjihan , Yunas Jumril , Latif Rhonira , Hamzah Azrul Azlan , Razip Wee Mohd Farhanulhakim Mohd , Yeop Majlis Burhanuddin
Published: May 2018

A simple fabrication method for the surface modification of an electroosmotic silicon microchannel using thermal dry oxidation is presented. The surface modification is done by coating the silicon surface with a silicon dioxide (SiO2) layer using a thermal oxidation process. The process aims not only to improve the surface quality of the channel to be suitable for electroosmotic fluid transport but also to reduce the channel width using a simple technique. Initially, the parallel microchannel array with dimensions of 0.5 mm length and a width ranging from 1.8 µm to 2 µm are created using plasma etching on the 2 cm × 2 cm silicon substrate <100>. The oxidation of the silicon channel in a thermal chamber is then conducted to create the SiO2 layer. The layer properties and the quality of the surface are analyzed using scanning electron microscopy (SEM) and a surface profiler, respectively. The results show that the maximum oxidation growth rate occurs in the first 4 h of oxidation time and the rate decreases over time as the oxide layer becomes thicker. It is also found that the surface roughness is reduced with the increase of the process temperature and the oxide thickness. The scallop effect on the vertical wall due to the plasma etching process also improved with the presence of the oxide layer. After oxidation, the channel width is reduced by ~40%. The demonstrated method is suggested for the fabrication of a uniform channel cross section with high aspect ratio in sub-micro and nanometer scale that will be useful for the electroosmotic (EO) ion manipulation of the biomedical fluid sample.
Acid Rock Drainage or Not—Oxidative vs. Reductive Biofilms—A Microbial Question
Authors: Kalin Margarete , Wheeler William N. , Bellenberg Sören
Published: May 2018

Measures to counteract Acid Rock Drainage (ARD) generation need to start at the mineral surface, inhibiting mineral-oxidizing, acidophilic microbes. Laboratory and long-term field tests with pyrite-containing mining wastes—where carbonaceous phosphate mining waste (CPMW) was added—resulted in low acidity and near neutral drainage. The effect was reproducible and confirmed by several independent research groups. The improved drainage was shown to involve an organic coating, likely a biofilm. The biofilm formation was confirmed when CPMW was added to lignite coal waste with an initial pH of 1. Forty-five days after the addition, the coal waste was dominated by heterotrophic microorganisms in biofilms. Reviewing the scientific literature provides ample support that CPMW has physical and chemical characteristics which can induce a strong inhibitory effect on sulphide oxidation by triggering the formation of an organic coating, a biofilm, over the mineral surface. CPMW characteristics provide the cornerstone of a new technology which might lead to reduction of sulphide oxidation in mine wastes. A hypothesis for testing this technology is presented. The use of such a technology could result in an economical and sustainable approach to mine waste and water management.
Changes and Distribution of Modes of Occurrence of Seventeen Potentially-Hazardous Trace Elements during Entrained Flow Gasification of Coals from Ningdong, China
Authors: Tang Yuegang , Guo Xin , Pan Xi , Finkelman Robert B. , Wang Yafeng , Huan Binbin , Wang Shaoqing
Published: May 2018

In order to reveal the migration of trace elements from coal to gasification residues, the modes of occurrence of potentially-hazardous trace elements (Be, V, Cr, Co, Ni, Cu, Zn, As, Se, Mo, Cd, Sb, Ba, Hg, Tl, Pb, and U) were determined by a five steps sequential chemical extraction procedure. Samples were collected from a coal-to-methanol plant (GE water-slurry coal gasification, formerly Texaco) and a coal-to-olefins plant (Gaskombimat Schwarze Pumpe pulverized coal gasification, GSP) in the Ningdong Energy and Chemical Industry Base, China. Concentrations of As and Se were determined using atomic fluorescence spectrometry (AFS). The content of Hg was determined using a DMA-80 mercury analyzer. Other trace elements (Be, Cr, Co, Ni, Cu, Zn, Mo, Cd, Sb, Ba, Tl, Pb, and U) were analyzed using inductively-coupled plasma mass spectrometry (ICP-MS). XRD and SEM-EDX were employed to determine the minerals or other inorganic phases in samples. The modes of occurrence of trace elements in feed coals can influence their behavior, including their volatility during coal gasification and, ultimately, the element’s mode of occurrence in the gasification residues. Knowing an element’s mode of occurrence in the feed coal may aid in anticipating which components the elements are likely to combine with during liquid slag cooling. Based on the relative enrichment of trace elements in the residues, elements Be, V, Cu, Mo, Ba, and Hg showed volatility during the GE and GSP gasification processes; As and Se showed volatilization-condensation behavior during the GE and GSP gasification processes; Cr, Ni, Zn, Cd, Sb, Tl, Pb, and U showed volatility during the GE gasification process; Zn, Cd, Sb, Pb, and Tl in the GSP samples, as well as Co in the GE samples, showed volatilization-condensation behavior; and Cr, Co, Ni, and U showed less volatility during the GSP gasification process. In the gasification residues, quartz, calcite, and Al–Si glass were the main inorganic phases, carbonates and iron and manganese oxides (likely recrystallized calcite) were the main hosts of most trace elements in the residues, including Be, V, Cr, Co, Ni, Zn, As, Cd, Ba, Hg, Tl, Pb, and U. Copper, Zn, Se, Cd, and Sb tended to stay in the Al–Si glass. Molybdenum is likely precipitated with the sulfides in the residues.
Various Physiological Response to Graphene Oxide and Amine-Functionalized Graphene Oxide in Wheat (Triticum aestivum)
Authors: Chen Juanni , Yang Liang , Li Shili , Ding Wei
Published: May 2018

An increasing number of investigations have been performed on the phytotoxicity of carbon-based nanomaterials duo to their extensive use in various fields. In the present study, we investigated the phytotoxicity of unfunctionalized graphene oxide (GO) and amine-functionalized graphene oxide (G-NH2) on wheat (Triticum aestivum) in the concentration range from 125 to 2000 μg/mL after 9 days of hydroponic culture. Our results found that the incubation with both nanomaterials did not affect the final seed germination rate, despite some influence in the initial stage. Transmission electron microscopy (TEM) observations indicated that exposure to GO at a high concentration (above 1000 μg/mL) resulted in a severe loss of morphology of seedlings, and a decrease in root length, shoot length and relative biomass, along with obvious damage to plant tissue structures (root, stem and leaf) when compared with the control. GO induced increased damage to root cells, which were determined by electrolyte leakage. Conversely, the plant growth was enhanced under G-NH2 exposure, and the root and stem lengths were increased by 19.27% and 19.61% at 2000 μg/mL, respectively. The plant tissue structures were not affected, and neither GO nor G-NH2 were observed to accumulate in the wheat plant root cells. The present investigations provide important information for evaluation of the environmental safety of GO and better understanding plant-nanoparticle interactions.
Tissue-Specific Analysis of Secondary Metabolites Creates a Reliable Morphological Criterion for Quality Grading of Polygoni Multiflori Radix
Authors: Liang Li , Xu Jun , Liang Zhi-Tao , Dong Xiao-Ping , Chen Hu-Biao , Zhao Zhong-Zhen
Published: May 2018

In commercial herbal markets, Polygoni Multiflori Radix (PMR, the tuberous roots of Polygonum multiflorum Thunb.), a commonly-used Chinese medicinal material, is divided into different grades based on morphological features of size and weight. While more weight and larger size command a higher price, there is no scientific data confirming that the more expensive roots are in fact of better quality. To assess the inherent quality of various grades and of various tissues in PMR and to find reliable morphological indicators of quality, a method combining laser microdissection (LMD) and ultra-performance liquid chromatography triple-quadrupole mass spectrometry (UPLC-QqQ-MS/MS) was applied. Twelve major chemical components were quantitatively determined in both whole material and different tissues of PMR. Determination of the whole material revealed that traditional commercial grades based on size and weight of PRM did not correspond to any significant differences in chemical content. Instead, tissue-specific analysis indicated that the morphological features could be linked with quality in a new way. That is, PMR with broader cork and phloem, as seen in a transverse section, were typically of better quality as these parts are where the bioactive components accumulate. The tissue-specific analysis of secondary metabolites creates a reliable morphological criterion for quality grading of PMR.
Synthesis of Water-Soluble Amino Functionalized Multithiacalix[4]arene via Quaternization of Tertiary Amino Groups
Authors: Nosov Roman , Padnya Pavel , Shurpik Dmitriy , Stoikov Ivan
Published: May 2018

A convenient approach to the synthesis of multithiacalix[4]arene derivatives containing amino groups and phthalimide fragments by the formation of quaternary ammonium salts is presented. As the initial macrocycle for the synthesis of multithiacalix[4]arenes, a differently substituted p-tert-butylthiacalix[4]arene containing bromoacetamide and three phthalimide fragments was used in a 1,3-alternate conformation. The macrocycle in cone conformation containing the tertiary amino groups was found to be a convenient core for the multithiacalix[4]arene systems. Interaction of the core multithiacalix[4]arene with monobromoacetamide derivatives of p-tert-butylthiacalix[4]arene resulted in formation in high yields of pentakisthiacalix[4]arene containing quaternary ammonium and phthalimide fragments. The removal of phthalimide groups led to the formation of amino multithiacalix[4]arene in a good yield. Based on dynamic light scattering, it was shown that the synthesized amino multithiacalix[4]arene, with pronounced hydrophobic and hydrophilic fragments, formed dendrimer-like nanoparticles in water via direct supramolecular self-assembly.
Transition Metal Hollow Nanocages as Promising Cathodes for the Long-Term Cyclability of Li–O2 Batteries
Authors: Chatterjee Amrita , Or Siu Wing , Cao Yulin
Published: May 2018

As a step towards efficient and cost-effective electrocatalytic cathodes for Li–O2 batteries, highly porous hausmannite-type Mn3O4 hollow nanocages (MOHNs) of a large diameter of ~250 nm and a high surface area of 90.65 m2·g−1 were synthesized and their physicochemical and electrochemical properties were studied in addition to their formation mechanism. A facile approach using carbon spheres as the template and MnCl2 as the precursor was adopted to suit the purpose. The MOHNs/Ketjenblack cathode-based Li–O2 battery demonstrated an improved cyclability of 50 discharge–charge cycles at a specific current of 400 mA·g−1 and a specific capacity of 600 mAh·g−1. In contrast, the Ketjenblack cathode-based one can sustain only 15 cycles under the same electrolytic system comprised of 1 M LiTFSI/TEGDME. It is surmised that the unique hollow nanocage morphology of MOHNs is responsible for the high electrochemical performance. The hollow nanocages were a result of the aggregation of crystalline nanoparticles of 25–35 nm size, and the mesoscopic pores between the nanoparticles gave rise to a loosely mesoporous structure for accommodating the volume change in the MOHNs/Ketjenblack cathode during electrocatalytic reactions. The improved cyclic stability is mainly due to the faster mass transport of the O2 through the mesoscopic pores. This work is comparable to the state-of-the-art experimentations on cathodes for Li–O2 batteries that focus on the use of non-precious transition materials.
Relationship of a Special Acidified Milk Protein Drink with Cognitive Performance: A Randomized, Double-Blind, Placebo-Controlled, Crossover Study in Healthy Young Adults
Authors: Saito Yoshie , Murata Natsuko , Noma Teruyuki , Itoh Hiroyuki , Kayano Mitsunori , Nakamura Kimihide , Urashima Tadasu
Published: May 2018

A previous in vivo study with rats suggested that a special milk protein drink manufactured using an acidification procedure to suppress the aggregation of milk proteins was absorbed quickly after feeding. We performed a randomized, double-blind, placebo-controlled, repeated-measure crossover study to investigate the short-term effects on cognitive performance in 29 healthy young adult men after they consumed this drink in the morning. After an overnight fast, subjects were tested for performance in the Uchida–Kraepelin serial arithmetic test and the Stroop test as well as for subjective feeling, body temperature, and heart rate variability before and after consumption of either the acidified milk protein drink or an isoenergetic placebo drink. Subjects showed a significant improvement in performance in the Uchida–Kraepelin test, the primary outcome measured, when they consumed the acidified milk protein drink compared with the placebo control condition. In addition, consumption of the acidified milk protein drink, compared with the placebo control, was associated with increases in vagally-mediated heart rate variability indices which, from recent theoretical perspectives, may reflect a higher ability to modulate cognitive and behavioral processes. There was no significant difference in subjective feelings and body temperature between the test drink conditions. These data suggest that consumption of the acidified milk protein drink may improve cognitive performance, with possible involvement of physiological systems that regulate cognition and behavior.
Anthropometric and Dietary Factors as Predictors of DNA Damage in Obese Women
Authors: Włodarczyk Marta , Jabłonowska-Lietz Beata , Olejarz Wioletta , Nowicka Grażyna
Published: May 2018

Enhanced DNA damage and disturbances in DNA repair mechanisms are reported to be involved in the pathogenesis of chronic diseases like obesity, atherosclerosis, metabolic syndrome, diabetes, and cancer. The aim of the present study was to evaluate whether anthropometric factors and dietary habits are related to endogenous DNA damage. One hundred and fourteen premenopausal, apparently healthy women were included in the study: 88 obese individuals and 26 controls. The comet assay was used to measure basal DNA damage. Biochemical measurements included lipids, apolipoproteinAI, fasting insulin, glucose, and C-reactive protein high sensitivity (CRP-hs). Dietary intakes were assessed by 3-day food records. The mean level of DNA damage was almost two times higher in obese than in non-obese women (p < 0.001). Regression modeling showed that body mass index (BMI), daily intakes of energy, and vitamin C are key predictors of variance in basal DNA damage. Our data demonstrate the impact of obesity-associated inflammation on DNA damage and indicate that regardless of obesity, the level of DNA damage can be reduced by adequate intakes of vitamins C and E. It suggests that particular attention should be paid to the content of antioxidants in the diet of obese people and further studies are needed to modify dietary guidelines to prevent DNA damage in obese individuals.
Beyond Plagiarism: Scientific Ethics and Its Other Aspects
Authors: Baykoucheva Svetla
Published: May 2018

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Mapping Arctic Bottomfast Sea Ice Using SAR Interferometry
Authors: Dammann Dyre O. , Eriksson Leif E. B. , Mahoney Andrew R. , Stevens Christopher W. , Van der Sanden Joost , Eicken Hajo , Meyer Franz J. , Tweedie Craig E.
Published: May 2018

Bottomfast sea ice is an integral part of many near-coastal Arctic ecosystems with implications for subsea permafrost, coastal stability and morphology. Bottomfast sea ice is also of great relevance to over-ice travel by coastal communities, industrial ice roads, and marine habitats. There are currently large uncertainties around where and how much bottomfast ice is present in the Arctic due to the lack of effective approaches for detecting bottomfast sea ice on large spatial scales. Here, we suggest a robust method capable of detecting bottomfast sea ice using spaceborne synthetic aperture radar interferometry. This approach is used to discriminate between slowly deforming floating ice and completely stationary bottomfast ice based on the interferometric phase. We validate the approach over freshwater ice in the Mackenzie Delta, Canada, and over sea ice in the Colville Delta and Elson Lagoon, Alaska. For these areas, bottomfast ice, as interpreted from the interferometric phase, shows high correlation with local bathymetry and in-situ ice auger and ground penetrating radar measurements. The technique is further used to track the seasonal evolution of bottomfast ice in the Kasegaluk Lagoon, Alaska, by identifying freeze-up progression and areas of liquid water throughout winter.
Speckle Suppression by Weighted Euclidean Distance Anisotropic Diffusion
Authors: Guo Fengcheng , Zhang Guo , Zhang Qingjun , Zhao Ruishan , Deng Mingjun , Xu Kai
Published: May 2018

To better reduce image speckle noise while also maintaining edge information in synthetic aperture radar (SAR) images, we propose a novel anisotropic diffusion algorithm using weighted Euclidean distance (WEDAD). Presented here is a modified speckle reducing anisotropic diffusion (SRAD) method, which constructs a new edge detection operator using weighted Euclidean distances. The new edge detection operator can adaptively distinguish between homogenous and heterogeneous image regions, effectively generate anisotropic diffusion coefficients for each image pixel, and filter each pixel at different scales. Additionally, the effects of two different weighting methods (Gaussian weighting and non-linear weighting) of de-noising were analyzed. The effect of different adjustment coefficient settings on speckle suppression was also explored. A series of experiments were conducted using an added noise image, GF-3 SAR image, and YG-29 SAR image. The experimental results demonstrate that the proposed method can not only significantly suppress speckle, thus improving the visual effects, but also better preserve the edge information of images.
A Range Ambiguity Suppression Processing Method for Spaceborne SAR with Up and Down Chirp Modulation
Authors: Wen Xuejiao , Qiu Xiaolan , Han Bing , Ding Chibiao , Lei Bin , Chen Qi
Published: May 2018

Range ambiguity is one of the factors which affect the SAR image quality. Alternately transmitting up and down chirp modulation pulses is one of the methods used to suppress the range ambiguity. However, the defocusing range ambiguous signal can still hold the stronger backscattering intensity than the mainlobe imaging area in some case, which has a severe impact on visual effects and subsequent applications. In this paper, a novel hybrid range ambiguity suppression method for up and down chirp modulation is proposed. The method can obtain the ambiguity area image and reduce the ambiguity signal power appropriately, by applying pulse compression using a contrary modulation rate and CFAR detecting method. The effectiveness and correctness of the approach is demonstrated by processing the archive images acquired by Chinese Gaofen-3 SAR sensor in full-polarization mode.
Filter Selection for Optimizing the Spectral Sensitivity of Broadband Multispectral Cameras Based on Maximum Linear Independence
Authors: Li Sui-Xian
Published: May 2018

Previous research has shown that the effectiveness of selecting filter sets from among a large set of commercial broadband filters by a vector analysis method based on maximum linear independence (MLI). However, the traditional MLI approach is suboptimal due to the need to predefine the first filter of the selected filter set to be the maximum ℓ2 norm among all available filters. An exhaustive imaging simulation with every single filter serving as the first filter is conducted to investigate the features of the most competent filter set. From the simulation, the characteristics of the most competent filter set are discovered. Besides minimization of the condition number, the geometric features of the best-performed filter set comprise a distinct transmittance peak along the wavelength axis of the first filter, a generally uniform distribution for the peaks of the filters and substantial overlaps of the transmittance curves of the adjacent filters. Therefore, the best-performed filter sets can be recognized intuitively by simple vector analysis and just a few experimental verifications. A practical two-step framework for selecting optimal filter set is recommended, which guarantees a significant enhancement of the performance of the systems. This work should be useful for optimizing the spectral sensitivity of broadband multispectral imaging sensors.