bluuebunny/crossref_metadata_2025 huggingface dataset:
Effective Establishment of Glide-Path to Reduce Torsional Stress during Nickel-Titanium Rotary Instrumentation
Authors: Abu-Tahun Ibrahim H. , Kwak Sang Won , Ha Jung-Hong , Sigurdsson Asgeir , Kayahan Mehmet Baybora , Kim Hyeon-Cheol
Published: February 2019

This study compared the torque generation during canal shaping with a nickel-titanium endodontic instrument according to the extent of glide-path establishment. Seventy-five simulated S-shaped canal blocks were divided into five groups (n = 15) according to the number of repetitive insertions to the working length using a One G glide-path instrument: groups with 5, 10, 15, and 20 insertions as well as group Z without glide-path establishment. When the tip of the One G file reached the working length, the file was moved back and forth repetitively at the working length for the designated number of times for each group. The instrumentation procedure with HyFlex EDM had 15 pecking strokes. During instrumentation, the generated torque was transmitted to a customized data acquisition module and collected using customized software. Data were computed to determine the maximum torque and total stress. The maximum screw-in forces were statistically analyzed using one-way analysis of variance and Tukey’s post hoc comparison test with a significance level of 95%. While the maximum stress did not have significant differences among the five groups (p > 0.05), groups with more than 10 repetitive insertions generated lower total stress during instrumentation than did the group with 5 insertions and group Z (p < 0.05). Under the limitations of this study, repetitive insertions of glide-path establishment files at the working length reduced stress generation during the shaping using nickel-titanium instruments.
Materials for Hip Prostheses: A Review of Wear and Loading Considerations
Authors: Merola Massimiliano , Affatato Saverio
Published: February 2019

Replacement surgery of hip joint consists of the substitution of the joint with an implant able to recreate the articulation functionality. This article aims to review the current state of the art of the biomaterials used for hip implants. Hip implants can be realized with different combination of materials, such as metals, ceramics and polymers. In this review, we analyze, from international literature, the specific characteristics required for biomaterials used in hip joint arthroplasty, i.e., being biocompatible, resisting heavy stress, opposing low frictional forces to sliding and having a low wear rate. A commentary on the evolution and actual existing hip prostheses is proposed. We analyzed the scientific literature, collecting information on the material behavior and the human-body response to it. Particular attention has been given to the tribological behavior of the biomaterials, as friction and wear have been key aspects to improve as hip implants evolve. After more than 50 years of evolution, in term of designs and materials, the actual wear rate of the most common implants is low, allowing us to sensibly reduce the risk related to the widespread debris distribution in the human body.
Role of LPSO Phase in Crack Propagation Behavior of an As-Cast Mg-Y-Zn Alloy Subjected to Dynamic Loadings
Authors: Shi Xuezhi , Long Yunqian , Zhang Huiqiu , Chen Liqiao , Zhou Yingtang , Yu Xiaoming , Yu Xuan , Cai Lu , Leng Zhe
Published: February 2019

In this work, the role of long period stacking ordered (LPSO) phase in the crack propagation behavior of an as-cast Mg95.5Y3Zn1.5 alloy was investigated by dynamic four-point bent tests. The as-cast Mg95.5Y3Zn1.5 alloy is mainly composed of Mg matrix, 18R LPSO phase located at the grain boundaries and 14H LPSO phase located within the Mg matrix. The alloy exhibits excellent dynamic mechanical properties; the yield stress, maximum stress and strain to failure are 190.51 ± 3.52 MPa, 378.32 ± 4.26 MPa and 0.168 ± 0.006, respectively, at the strain rate of ~3000 s−1. The LPSO phase effectively hinders dynamic crack propagation in four typical ways, including crack tip blunting, crack opening inhibition, crack deflection and crack bridging, which are beneficial to the mechanical properties of the alloy under dynamic loadings.
Microstructure Evolution and Mechanical Stability of Retained Austenite in Thermomechanically Processed Medium-Mn Steel
Authors: Grajcar Adam , Kilarski Andrzej , Kozłowska Aleksandra , Radwański Krzysztof
Published: February 2019

A microstructure evolution of the thermomechanically processed 3Mn-1.5Al type steel and mechanical stability of retained austenite were investigated during interrupted tensile tests. The microstructural details were revealed using scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM) techniques. It was found that the strain-induced martensitic transformation began in central regions of the largest blocky-type grains of retained austenite and propagated to outer areas of the grains as the deformation level increased. At rupture, the mechanical stability showed only boundaries of fine blocky grains of γ phase and austenitic layers located between bainitic ferrite laths. The effects of various carbon enrichment, grain size, and location in the microstructure were considered. The martensitic transformation progress was the highest at the initial stage of deformation and gradually decreased as the deformation level increased.
Ground State Solutions for Fractional Choquard Equations with Potential Vanishing at Infinity
Authors: Luo Huxiao , Li Shengjun , Li Chunji
Published: February 2019

In this paper, we study a class of nonlinear Choquard equation driven by the fractional Laplacian. When the potential function vanishes at infinity, we obtain the existence of a ground state solution for the fractional Choquard equation by using a non-Nehari manifold method. Moreover, in the zero mass case, we obtain a nontrivial solution by using a perturbation method. The results improve upon those in Alves, Figueiredo, and Yang (2015) and Shen, Gao, and Yang (2016).
Sehgal Type Contractions on Dislocated Spaces
Authors: Alqahtani Badr , Fulga Andreea , Karapınar Erdal , Kumari Panda Sumati
Published: February 2019

In this paper, we investigate the contractive type inequalities for the iteration of the mapping at a given point in the setting of dislocated metric space. We consider an example to illustrate the validity of the given result. Further, as an application, we propose a solution for a boundary value problem of the second order differential equation.
High Performance Fine-Grained Biodegradable Mg-Zn-Ca Alloys Processed by Severe Plastic Deformation
Authors: Vinogradov Alexei , Vasilev Evgeni , Kopylov Vladimir I. , Linderov Mikhail , Brilevesky Alexander , Merson Dmitry
Published: February 2019

The tensile strength, fatigue, and corrosion fatigue performance of the magnesium alloy ZX40 benefit strongly from hybrid deformation processing involving warm equal-channel angular pressing (ECAP) at the first step and room temperature rotary swaging at the second. The general corrosion resistance improved as well, though to a lesser extent. The observed strengthening is associated with a combined effect of substantial microstructure refinement down to the nanoscale, reducing deformation twinning activity, dislocation accumulation, and texture transformation. The ultimate tensile strength and the endurance limit in the ultrafine-grained material reached or exceeded 380 and 120 MPa, respectively, which are remarkable values for this nominally low strength alloy.
Investigation of Microstructure, Nanohardness and Corrosion Resistance for Oxi-Nitrocarburized Low Carbon Steel
Authors: Cho Young-Wook , Kang Young-Joon , Baek Ju-Hwan , Woo Jeong-Ho , Cho Young-Rae
Published: February 2019

A role of oxi-nitrocarburizing technique for low-carbon steel was intensively evaluated as a means of reducing the problem of corrosion in gas nitrocarburizing, which is a vital disadvantage of gas nitrocarburizing. Oxi-nitrocarburizing was carried out by a two-step process: Gas nitrocarburizing at 560 °C and oxidation. In order to characterize two different methods of oxi-nitrocarburizing, oxidation was performed under two different conditions: Air and steam as oxygen sources. To analyze the microstructural, physical, and chemical properties of the thin oxide layer and nitride layer, which are the surface hardened layers formed on low-carbon steel by oxi-nitrocarburizing, several methods, such as electron probe microanalysis (EPMA), electron backscattered diffraction (EBSD), scanning electron microscopy (SEM), nanoindentation tests, and potentiodynamic polarization tests were applied. The results indicated that the EPMA and EBSD methods are powerful techniques for the analysis of microstructure, such as phase analysis and metallic element distribution in the oxide layer of magnetite and compound layer of ε-phase and γ′-phase, for oxi-nitrocarburized low-carbon steel. Additionally, the nanohardness using the nanoindentation test and corrosion resistance using the potentiodynamic polarization test for the oxi-nitrocarburized specimens are useful methods to understand the mechanical and corrosion properties of the surface hardened layer.
Microwave-Assisted Stereoselective Heterocyclization to Novel Ring d-fused Arylpyrazolines in the Estrone Series
Authors: Mótyán Gergő , Molnár Barnabás , Wölfling János , Frank Éva
Published: February 2019

Microwave-assisted syntheses of novel ring d-condensed 2-pyrazolines in the estrone series were efficiently carried out from steroidal α,β-enones and hydrazine derivatives. The ring-closure reaction of 16-benzylidene estrone 3-methyl ether with hydrazine in acetic acid resulted in a 2:1 diastereomeric mixture of two 16,17-cis fused pyrazolines, which is contrary to the former literature data for both stereoselectivity and product structure. However, the cyclization reactions of a mestranol-derived unsaturated ketone with different arylhydrazines in acidic ethanol furnished the heterocyclic products in good to excellent yields independently of the substituents present on the aromatic ring of the reagents applied. The MW conditions also permitted the ring-closure reaction with p-nitrophenylhydrazine which is unfavorable under conventional heating. Moreover, the transformations led to the heterocyclic compounds stereoselectively with a 16α,17α-cis ring junction without being susceptible to spontaneous and promoted oxidation to pyrazoles.
Investigating the Effect of Mono- and Dimeric 360A G-Quadruplex Ligands on Telomere Stability by Single Telomere Length Analysis (STELA)
Authors: Hwang In Pyo , Mailliet Patrick , Hossard Virginie , Riou Jean-Francois , Bugaut Anthony , Roger Lauréline
Published: February 2019

Telomeres are nucleoprotein structures that cap and protect the natural ends of chromosomes. Telomeric DNA G-rich strands can form G-quadruplex (or G4) structures. Ligands that bind to and stabilize G4 structures can lead to telomere dysfunctions by displacing shelterin proteins and/or by interfering with the replication of telomeres. We previously reported that two pyridine dicarboxamide G4 ligands, 360A and its dimeric analogue (360A)2A, were able to displace in vitro hRPA (a single-stranded DNA-binding protein of the replication machinery) from telomeric DNA by stabilizing the G4 structures. In this paper, we perform for the first time single telomere length analysis (STELA) to investigate the effect of G4 ligands on telomere length and stability. We used the unique ability of STELA to reveal the full spectrum of telomere lengths at a chromosome terminus in cancer cells treated with 360A and (360A)2A. Upon treatment with these ligands, we readily detected an increase of ultrashort telomeres, whose lengths are significantly shorter than the mean telomere length, and that could not have been detected by other methods.
Design, Synthesis and Biological Evaluation of Nitrate Derivatives of Sauropunol A and B as Potent Vasodilatory Agents
Authors: Lu Lu , Rao Xuemin , Cong Rigang , Zhang Chenxi , Wang Zhimei , Xu Jinyi , Tanabe Genzoh , Muraoka Osamu , Wu Xiaoming , Xie Weijia
Published: February 2019

A group of nitrate derivatives of naturally occurring sauropunol A and B were designed and synthesized. Nitric oxide (NO) releasing capacity and vasodilatory capacity studies were performed to explore the structure-activity relationship of resulted nitrates. Biological evaluation of these compounds revealed that most of the synthesized mononitrate derivatives demonstrated superior releasing capacity than isosorbide mononitrate (ISMN), and 2MNS-6 even demonstrated stronger NO releasing capacity than isosorbide dinitrate (ISDN). Two dinitrates, DNS-1 and DNS-2, showed higher NO releasing capacity than ISDN. Evaluation of inhibitory activities to the contractions in mesenteric artery rings revealed that 2MNS-8 and DNS-2 showed stronger vasorelaxation activities than ISDN. High level of NO and soluble guanylyl cyclase (sGC) may be essential for the potent vasodilatory effect of DNS-2. The vasodilatory effects of DNS-2 may result from cellular signal transduction of NO-sGC-cGMP. DNS-2 was found to be the most potent sauropunol-derived nitrate vasodilatory agent for further pharmaceutical investigation against cardiovascular diseases.
Extraction of Microbial and Host DNA, RNA, and Proteins from Oak Bark Tissue
Authors: Broberg Martin , McDonald James E.
Published: February 2019

The application of high-throughput nucleic acid and protein sequencing technologies is transforming our understanding of plant microbiomes and their interactions with their hosts in health and disease. However, progress in studying host-microbiome interactions in above-ground compartments of the tree (the phyllosphere) has been hampered due to high concentrations of phenolic compounds, lignin, and other compounds in tree bark that severely limit the success of DNA, RNA, and protein extraction. Here we present modified sample-preparation and kit-based protocols for the extraction of host and microbiome DNA and RNA from oak (Quercus robus and Quercus petraea) bark tissue for subsequent high-throughput sequencing. In addition, reducing the quantity of bark tissue used for an established protein extraction protocol yielded high quality protein for parallel analysis of the oak-microbiota metaproteome. These procedures demonstrate the successful extraction of nucleic acids and proteins from oak tissue using as little as 50 mg of sample input, producing sufficient quantities for nucleic acid sequencing and protein mass spectrometry of tree stem tissues and their associated microbiota.
Doxorubicin Loaded Magnesium Oxide Nanoflakes as pH Dependent Carriers for Simultaneous Treatment of Cancer and Hypomagnesemia
Authors: Ranathunge Tharindu A. , Karunaratne D.G.G.P. , Rajapakse R.M.G. , Watkins Davita L.
Published: February 2019

Doxorubicin (DOX) is an anticancer drug commonly used in treating cancer; however, it has severe cytotoxicity effects. To overcome both the adverse effects of the drug and mineral deficiency (i.e., hypomagnesemia) experienced by cancer patients, we have developed magnesium oxide (MgO) nanoflakes as drug carriers and loaded them with DOX for use as a targeted drug delivery (TDD) system for potential application in cancer therapy. The synthesis employed herein affords pure, highly porous MgO nanoparticles that are void of the potentially harmful metal contaminants often discussed in the literature. Purposed for dual therapy, the nanoparticles exhibit an impressive 90% drug loading capacity with pH dependent drug releasing rates of 10% at pH 7.2, 50.5% at pH 5.0, and 90.2% at pH 3. Results indicate that therapy is achievable via slow diffusion where MgO nanoflakes degrade (i.e., dissolve) under acidic conditions releasing the drug and magnesium ions to the cancerous region. The TDD system therefore minimizes cytotoxicity to healthy cells while supplying magnesium ions to overcome hypomagnesemia.
Efficient Copper Removal from an Aqueous Anvironment using a Novel and Hybrid Nanoadsorbent Based on Derived-Polyethyleneimine Linked to Silica Magnetic Nanocomposites
Authors: Plohl Olivija , Finšgar Matjaž , Gyergyek Sašo , Ajdnik Urban , Ban Irena , Zemljič Lidija Fras
Published: February 2019

Due to the extreme rise of sludge pollution with heavy metals (e.g. copper), the options for its disposal or treatment are decreasing. On the contrary, properly heavy metal-cleaned sludge can be used as an alternative sustainable energy and agriculture source. The aim of this study was to develop a novel nanoadsorbent, based on irreversibly linked amino-rich polymer onto previously silica-coated magnetic nanoparticles (MNPs) that can be applied efficiently for metal removal. MNPs were coated uniformly by 3 nm thick silica layer (core-shell structure), and were additionally modified with systematic covalent attachment of derived branched polyethyleneimine (bPEI). The formed structure of synthesized MNPs composite was confirmed with several analytical techniques. Importantly, nanoadsorbents exhibit high density of chelating amino groups and large magnetic force for easier separation. The importance of introduced bPEI, effect of pH, initial heavy metal concentration onto copper uptake efficiency and, further, nanoadsorbent regeneration, were studied and explained in detail. The adsorption isotherm was well fitted with Langmuir model, and the maximum adsorption capacity was shown to be 143 mg·g−1 for Cu2+. The reusability and superior properties of silica-coated MNPs functionalized with derived-bPEI for copper adsorption underlie its potential for the removal application from heavy metals contaminated sludge
Effect of Salinity on Silica Nanoparticle Adsorption Kinetics and Mechanisms for Fluid/Rock Interaction with Calcite
Authors: Hamouda Aly A. , Abhishek Rockey
Published: February 2019

This study addresses the kinetics of silica nanoparticle adsorption on calcite from a solution at three salinities: deionized water (DIW), synthetic seawater (SSW), and low salinity water (LSW). The nanoparticle adsorption mechanisms and the effects on calcite dissolution are addressed. It was shown that nanoparticle adsorption was best described with the second-order-kinetic model and that silica nanoparticle adsorption reduced calcite dissolution. This was confirmed by measuring the Ca2+ ion concentration, the pH, and by estimating the amount of calcite dissolved. This is an important conclusion of this work, especially as LSW as an enhanced oil recovery technique is a candidate for use in chalk fields. Less formation damage/dissolution of chalk when silica nanoparticles are combined with LSW can lower the risk of reservoir subsidence. Intraparticle diffusion and the pseudo-second-order models, indicated a reduction in the adsorption rate with increasing nanoparticle concentration in LSW. This is explained by possible repulsive forces among the nanoparticles as they diffuse from the bulk fluid onto the calcite surface. Ion charges reduce the repulsion among the nanoparticles through shielding. However, an increasing nanoparticle concentration reduces the shielding efficiency by the ions. Estimates of the surface forces confirmed that nanoparticle–mineral interaction is less attractive in LSW as compared to SSW and DIW.
Femtosecond Spectroscopy of Au Hot-Electron Injection into TiO2: Evidence for Au/TiO2 Plasmon Photocatalysis by Bactericidal Au Ions and Related Phenomena
Authors: Radzig Marina , Koksharova Olga , Khmel Inessa , Ivanov Vladimir , Yorov Khursand , Kiwi John , Rtimi Sami , Tastekova Elina , Aybush Arseny , Nadtochenko Victor
Published: February 2019

In the present work, we provide evidence for visible light irradiation of the Au/TiO2 nanoparticles’ surface plasmon resonance band (SPR) leading to electron injection from the Au nanoparticles to the conduction band of TiO2. The Au/TiO2 SPR band is shown to greatly enhance the light absorption of TiO2 in the visible region. Evidence is presented for the light absorption by the Au/TiO2 plasmon bands leading to the dissolution of Au nanoparticles. This dissolution occurs concomitantly with the injection of the hot electrons generated by the Au plasmon into the conduction band of TiO2. The electron injection from the Au nanoparticles into TiO2 was followed by femtosecond spectroscopy. The formation of Au ions was further confirmed by the spectral shift of the transient absorption spectra of Au/TiO2. The spectral changes of the SPR band of Au/TiO2 nanoparticles induced by visible light were detected by spectrophotometer, and the morphological transformation of Au/TiO2 was revealed by electron microscopy techniques as well. Subsequently, the fate of the Au ions was sorted out during the growth and biofilm formation for some selected Gram-negative bacteria. This study compares the bactericidal mechanism of Au ions and Ag ions, which were found to be substantially different depending on the selected cell used as a probe.
Autism Spectrum Disorder (ASD) with and without Mental Regression Is Associated with Changes in the Fecal Microbiota
Authors: Plaza-Díaz Julio , Gómez-Fernández Antonio , Chueca Natalia , Torre-Aguilar María José de la , Gil Ángel , Perez-Navero Juan Luis , Flores-Rojas Katherine , Martín-Borreguero Pilar , Solis-Urra Patricio , Ruiz-Ojeda Francisco Javier , Garcia Federico , Gil-Campos Mercedes
Published: February 2019

New microbiome sequencing technologies provide novel information about the potential interactions among intestinal microorganisms and the host in some neuropathologies as autism spectrum disorders (ASD). The microbiota–gut–brain axis is an emerging aspect in the generation of autistic behaviors; evidence from animal models suggests that intestinal microbial shifts may produce changes fitting the clinical picture of autism. The aim of the present study was to evaluate the fecal metagenomic profiles in children with ASD and compare them with healthy participants. This comparison allows us to ascertain how mental regression (an important variable in ASD) could influence the intestinal microbiota profile. For this reason, a subclassification in children with ASD by mental regression (AMR) and no mental regression (ANMR) phenotype was performed. The present report was a descriptive observational study. Forty-eight children aged 2–6 years with ASD were included: 30 with ANMR and 18 with AMR. In addition, a control group of 57 normally developing children was selected and matched to the ASD group by sex and age. Fecal samples were analyzed with a metagenomic approach using a next-generation sequencing platform. Several differences between children with ASD, compared with the healthy group, were detected. Namely, Actinobacteria and Proteobacteria at phylum level, as well as, Actinobacteria, Bacilli, Erysipelotrichi, and Gammaproteobacteria at class level were found at higher proportions in children with ASD. Additionally, Proteobacteria levels showed to be augmented exclusively in AMR children. Preliminary results, using a principal component analysis, showed differential patterns in children with ASD, ANMR and AMR, compared to healthy group, both for intestinal microbiota and food patterns. In this study, we report, higher levels of Actinobacteria, Proteobacteria and Bacilli, aside from Erysipelotrichi, and Gammaproteobacteria in children with ASD compared to healthy group. Furthermore, AMR children exhibited higher levels of Proteobacteria. Further analysis using these preliminary results and mixing metagenomic and other “omic” technologies are needed in larger cohorts of children with ASD to confirm these intestinal microbiota changes.
Assessment of Vitamin Status in Patients with Nontuberculous Mycobacterial Pulmonary Disease: Potential Role of Vitamin A as a Risk Factor
Authors: Oh Jongwon , Park Hyung-Doo , Kim Su-Young , Koh Won-Jung , Lee Soo-Youn
Published: February 2019

As microbiological diagnostic techniques improve and the frequency of nontuberculous mycobacterial pulmonary disease (NTM-PD) infection increases worldwide, NTM-PD is becoming increasingly important to clinicians and researchers. Vitamin activity has been associated with the host immune response in tuberculosis; however, such information is very limited in NTM-PD. We performed a case-control study in 150 patients with NTM-PD and 150 healthy controls to investigate serum vitamin status. We measured concentrations of vitamins A, D, and E along with homocysteine and methylmalonic acid (MMA) as indicators of vitamin B12 deficiency, using high-performance liquid chromatography (HPLC) or HPLC-tandem mass spectrometry. The serum concentrations of vitamins A and E were significantly lower in patients with NTM-PD than in healthy controls (1.5 vs. 2.1 µmol/L, p < 0.01 for vitamin A; and 27.3 vs. 33.1 µmol/L, p < 0.01 for vitamin E). In contrast, the serum concentrations of vitamin D and homocysteine were not significantly different between the two groups. Vitamin A deficiency (< 1.05 µmol/L) was significantly more prevalent in patients with NTM-PD than in healthy controls (p < 0.01) and was associated with an 11-fold increase in risk of NTM-PD. Multiple vitamin deficiencies were only observed in patients with NTM-PD (7.3% of all NTM-PD patients). Positive correlations were observed among vitamins (vitamins A and D; r = 0.200, p < 0.05; vitamins D and E, r = 0.238, p < 0.05; vitamins A and E, r = 0.352, p < 0.05). Serum vitamin status, demographic variables, and biochemical indicators were not associated with treatment outcomes. Vitamin A deficiency was strongly associated with patients with NTM-PD. Our study suggests that altered vitamin status is associated with mycobacterial disease. Future well-designed prospective studies with large patient cohorts addressing these issues are needed to clarify the significance of vitamins in NTM-PD.
Dietary Fiber Intake (Supplemental or Dietary Pattern Rich in Fiber) and Diabetic Kidney Disease: A Systematic Review of Clinical Trials
Authors: Mesquita de Carvalho Cláudia , Azevedo Gross Luiza , Jobim de Azevedo Mirela , Verçoza Viana Luciana
Published: February 2019

Fiber intake is associated with better glycemic control being an important non-pharmacological treatment for diabetes (DM). We hypothesize that a dietary fiber intake can bring benefits to diabetic kidney disease (DKD), improving renal outcomes. This systematic review aimed to evaluate the effect of dietary fiber (supplemental or dietary pattern rich in fiber) on DKD. We searched six databases to identify clinical trials that reported fiber intake and renal outcomes (albuminuria, proteinuria, estimated glomerular filtration rate (eGFR) dialysis) in patients with DM. From 1814 studies, 48 papers were fully evaluated. In the end, seven trials (161 patients, aged 58.3 years, 49% females) were included. The studies were organized into three categories (vegetarian, Dietary Approaches to Stop Hypertension (DASH) diet, and fiber supplement), two evaluated supplements and five dietary patterns. Vegetarian diet reduced albuminuria in three trials, two in patients with type 1 DM and one in patients with type 2 DM; and one study demonstrated a change in the eGFR in type 1 DM. The individual quality of the studies was low/uncertain. A vegetarian dietary pattern may have a beneficial effect on these renal outcomes. However, the individual effect of the intake of fiber on DKD not was possible to be evaluated.
The Experimental Infections of the Human Isolate of Strongyloides Stercoralis in a Rodent Model (The Mongolian Gerbil, Meriones Unguiculatus)
Authors: Charuchaibovorn Sarit , Sanprasert Vivornpun , Nuchprayoon Surang
Published: February 2019

Strongyloidiasis is life-threatening disease which is mainly caused by Strongyloides stercoralis infection. Autoinfection of the parasite results in long-lasting infection and fatal conditions, hyperinfection and dissemination (primarily in immunosuppressed hosts). However, mechanisms of autoinfection and biology remain largely unknown. Rodent models including mice and rats are not susceptible to the human isolate of S. stercoralis. Variations in susceptibility of the human isolate of S. stercoralis are found in dogs. S. ratti and S. venezuelensis infections in rats are an alternative model without the ability to cause autoinfection. The absence of appropriate model for the human isolate of strongyloidiasis hampers a better understanding of human strongyloidiasis. We demonstrated the maintenance of the human isolate of the S. stercoralis life cycle in the Mongolian gerbil (Meriones unguiculatus). The human isolate of S. stercoralis caused a patent infection in immunosuppressed gerbils, more than 18 months. The mean number of recovery adult parasitic worms were 120 ± 23 (1.2% of the initial dose) and L1s were 12,500 ± 7500 after day 28 post-inoculation (p.i.). The prepatent period was 9–14 days. Mild diarrhoea was found in gerbils carrying a high number of adult parasitic worms. Our findings provided a promising model for studying biology and searching new alternative drugs against the parasites. Further studies about the hyperinfection and dissemination would be performed.
Amorphisation of Free Acid Ibuprofen and Other Profens in Mixtures with Nanocellulose: Dry Powder Formulation Strategy for Enhanced Solubility
Authors: Mantas Athanasios , Labbe Valentine , Loryan Irena , Mihranyan Albert
Published: February 2019

The formulation of arylpropionic acid derivatives (profens), which are poorly soluble Biopharmaceutical Classification System (BCS) Type II drugs, has a strong impact on their therapeutic action. This article shows that heat-treated powder mixtures of free acid profens with high surface area Cladophora cellulose induces drug amorphization and results in enhanced solubility and bioavailability. Similar mixtures produced using conventional low surface area cellulose, i.e., microcrystalline cellulose, does not produce the same effect. The concept is thoroughly described and links the solid-state characterization data, such as differential scanning calorimetry, X-ray powder diffraction, and Fourier-transform infra-red spectroscopy, with in vitro dissolution in biorelevant media and in vivo pharmacokinetic analysis in rats. The concept is demonstrated for several substances from the profens group, including ibuprofen (main model drug), ketoprofen, flurbiprofen, and naproxen. The presented approach opens new ways to produce solid dosage forms of profen drugs in their free acidic form as alternatives to existing analogues, e.g., drug-salt conjugates or soft gel liquid capsules.
Effect of Lecithin on the Spontaneous Crystallization of Enzymatically Synthesized Short-Chain Amylose Molecules into Spherical Microparticles
Authors: Letona Carlos Andres Morales , Luo Ke , Jeong Ki-Baek , Adra Hazzel Joy , Park Cheon-Seok , Kim Young-Rok
Published: February 2019

Here, we report a facile and effective one-pot approach to prepare uniform amylose-based polymeric microparticles (PMPs) through enzymatic synthesis of short-chain amylose (SCA) followed by spontaneous self-assembly of the SCA in the presence of lecithin. The effect of lecithin on nucleation and growth kinetics of amylose microparticles was investigated by monitoring the turbidity of reaction solution and the size of particles over the course of the self-assembly process. The results suggest that lecithin played a critical role in controlling the self-assembly kinetics to form uniform amylose microparticles through steric stabilization of the growing particles and diffusion-limited growth effect. The crystallinity of amylose microparticles was not affected by lecithin, implying that lecithin did not disrupt the crystal structure within the particle and would mainly be present on the surface of the microparticles. Considering its biodegradable and biocompatible nature, the amylose-based microparticles would find a range of useful applications in the area of food, cosmetics, medicine, chromatography and other related materials sciences.
Preparation of Prussian Blue Containing Polymeric Nanocapsule via Interfacial Confined Coordination in Crosslinked Inverse Miniemulsion
Authors: Wu Lin , Pang Tao , Guan Yebin , Li Yiguo
Published: February 2019

This work presents a simple and facile strategy for the creation of Prussian blue containing polymeric nanocapsules. An crosslinked inverse miniemulsion with a formula of water/ K4Fe(CN)6/1,2-bis-(-2-iodoethyl) ethane(BIEE)/ toluene/ PDMAEMA-b-PS stabilizer mixture was prepared as soft template firstly. A crosslinking nanocapsule structure with K4Fe(CN)6 in water core could be achieved by a crosslinking reaction between PDMAEMA-b-PS stabilizers and BIEE. Upon the following addition of FeCl3 ether solution into the oil phase of this inverse miniemulsion, a coordination reaction between two iron salts occurred immediately to form a Prussian blue complex. Due to the solubility limitation of FeCl3 in the oil phase of the miniemulsion, forcing the coordination reaction of K4Fe(CN)6 and FeCl3 mainly occurred at the oil-water interface of the nanocapsules, resulting in a soft polymer/Prussian blue(PB) hybrid nanocapsule.
Noncovalent Complexation of Amphotericin B with Poly(β-Amino Ester) Derivates for Treatment of C. Neoformans Infection
Authors: Yu Yang , Peng Li , Liao Guojian , Chen Zhangbao , Li Chong
Published: February 2019

Our goal was to improve treatment outcomes for C. neoformans infection by designing nanocarriers that enhance drug-encapsulating capacity and stability. Thus, a noncovalent complex of methoxy poly(ethylene glycol)-poly(lactide)-poly(β-amino ester) (MPEG-PLA-PAE) and amphotericin B (AMB) was developed and characterized. The MPEG-PLA-PAE copolymer was synthesized by a Michael-type addition reaction; the copolymer was then used to prepare the AMB-loaded nanocomplex. AMB was in a highly aggregated state within complex cores. A high encapsulation efficiency (>90%) and stability of the AMB-loaded nanocomplex were obtained via electrostatic interaction between AMB and PAE blocks. This nanocomplex retained drug activity against C. neoformans in vitro. Compared with micellar AMB, the AMB nanocomplex was more efficient in terms of reducing C. neoformans burden in lungs, liver, and spleen, based on its improved biodistribution. The AMB/MPEG-PLA-PAE complex with enhanced drug-loading capacity and stability can serve as a platform for effective treatment of C. neoformans infection.
Green-Synthesis of Anisotropic Peptone-Silver Nanoparticles and Its Potential Application as Anti-Bacterial Agent
Authors: Kim Min , Jee Seung-Cheol , Shinde Surendra K. , Mistry Bhupendra M. , Saratale Rijuta Ganesh , Saratale Ganesh Dattatraya , Ghodake Gajanan S. , Kim Dae-Young , Sung Jung-Suk , Kadam Avinash A.
Published: February 2019

This study demonstrates a green-route-based synthesis of high-concentration suspensions of anisotropic silver nanoparticles (AgNPs) by peptone (Pep), a soluble protein hydrolysate and an abundantly used nutrient source in microbial-media. The transformation of Ag ions from solution into a high-concentration suspension of anisotropic Pep-AgNPs, at an extremely low concentration of peptone (0.02%), indicates that the present green-route synthesis method follows “low volume high concentration nano-synthesis”, and, hence, enhances the economic significance of the process. Process optimization with different concentrations of AgNPs (1–5 mM), NaOH solution (5–40 mM), and peptone (0.004%–0.12%) gave the optimized Pep-AgNPs synthesis at 3 mM of AgNO3, 20 mM of NaOH, and 0.02% of the peptone concentrations. The green-route synthesized Pep-AgNPs were structurally characterized by the TEM, XPS, FT-IR, and XRD analyses. The Pep-AgNPs against the clinically relevant bacteria Escherichia coli and Staphylococcus aureus gave significant anti-bacterial properties, with a MIC (minimum inhibitory concentration) of 100 ppm. The colony counting and morphological observation of the bacterial cell under SEM corroborated an anti-bacterial potential of the Pep-AgNPs. Therefore, Pep-AgNPs are green-route synthesized, anisotropic, and have a significant anti-bacterial potential that can be used in many relevant applications.
Transparent to Black Electrochromism—The “Holy Grail” of Organic Optoelectronics
Authors: Jarosz Tomasz , Gebka Karolina , Stolarczyk Agnieszka , Domagala Wojciech
Published: February 2019

In the rapidly developing field of conjugated polymer science, the attribute of electrochromism these materials exhibit provides for a multitude of innovative application opportunities. Featuring low electric potential driven colour change, complemented by favourable mechanical and processing properties, an array of non-emissive electrochromic device (ECD) applications lays open ahead of them. Building up from the simplest two-colour cell, multielectrochromic arrangements are being devised, taking advantage of new electrochromic materials emerging at a fast pace. The ultimate device goal encompasses full control over the intensity and spectrum of passing light, including the two extremes of complete and null transmittance. With numerous electrochromic device architectures being explored and their operating parameters constantly ameliorated to pursue this target, a summary and overview of developments in the field is presented. Discussing the attributes of reported electrochromic systems, key research points and challenges are identified, providing an outlook for this exciting topic of polymer material science.
Helix-Sense-Selective Polymerization of Phenylacetylenes Having a Porphyrin and a Zinc-Porphyrin Group: One-Handed Helical Arrangement of Porphyrin Pendants
Authors: Teraguchi Masahiro , Nahata Nobuyuki , Nishimura Takahiro , Aoki Toshiki , Kaneko Takashi
Published: February 2019

Newly synthesized two kinds of achiral phenylacetylenes having a free-base- or a zinc-porphyrin (1 and Zn1, respectively) were polymerized by using a chiral rhodium catalyst system, Rh+(nbd)[(η6-C6H5)B–(C6H5)3] catalyst and (R)-(+)- or (S)-(–)-1-phenylethylamine ((R)- or (S)-PEA, respectively) cocatalyst. Poly(1) and poly(Zn1) in THF showed a Cotton signal at the absorption region of the porphyrin and the main chain in the circular dichroism (CD) spectra. This result suggests that poly(1) and poly(Zn1) exist in a conformation with an excess of one-handed helix sense and the porphyrin moiety arranged in chiral helical fashion. The one-handed helical structure of poly(1) could be sustained in a mixture of THF/HMPA (10/2, v/v) due to stabilizing by stacking effect of porphyrin moieties along the main chain. This is the first example about helix-sense-selective polymerization by using Rh+(nbd)[(η6-C6H5)B–(C6H5)3] catalyst. Additionally, poly(Zn1) showed about 10 times larger CD intensity in comparison with poly(1). This result suggests the regularity of arrangement of the porphyrin in poly(Zn1) is higher compared with poly(1). Spatial arrangement of porphyrins was achieved by utilizing a one-handed helical poly(phenylacetylenes) as a template.
Enhanced Formaldehyde Removal from Air Using Fully Biodegradable Chitosan Grafted β-Cyclodextrin Adsorbent with Weak Chemical Interaction
Authors: Yang Zujin , Miao Hongchen , Rui Zebao , Ji Hongbing
Published: February 2019

Formaldehyde (HCHO) is an important indoor air pollutant. Herein, a fully biodegradable adsorbent was synthesized by the crosslinking reaction of β-cyclodextrin (β-CD) and chitosan via glutaraldehyde (CGC). The as-prepared CGC showed large adsorption capacities for gaseous formaldehyde. To clarify the adsorption performance of the as-synthesized HCHO adsorbents, changing the adsorption parameters performed various continuous flow adsorption tests. It was found that the adsorption data agreed best with the Freundlich isotherm, and the HCHO adsorption kinetic data fitted well with the pseudo second order model. The breakthrough curves indicated that the HCHO adsorbing capacity of CGC was up to 15.5 mg/g, with the inlet HCHO concentration of 46.1 mg/m3, GHSV of 28 mL/min, and temperature of 20 °C. The regeneration and reusability of the adsorbent were evaluated and CGC was found to retain its adsorptive capacity after four cycles. The introduction of β-CD was a key factor for the satisfied HCHO adsorption performance of CGC. A plausible HCHO adsorption mechanism by CGC with the consideration of the synergistic effects of Schiff base reaction and the hydrogen bonding interaction was proposed based on in situ DRIFTS studies. The present study suggests that CGC is a promising adsorbent for the indoor formaldehyde treatment.
Relationship Between MiRKAT and Coefficient of Determination in Similarity Matrix Regression
Authors: Zhan Xiang
Published: February 2019

The Microbiome Regression-based Kernel Association Test (MiRKAT) is widely used in testing for the association between microbiome compositions and an outcome of interest. The MiRKAT statistic is derived as a variance-component score test in a kernel machine regression-based generalized linear mixed model. In this brief report, we show that the MiRKAT statistic is proportional to the R 2 (coefficient of determination) statistic in a similarity matrix regression, which characterizes the fraction of variability in outcome similarity, explained by microbiome similarity (up to a constant).
Reaction Kinetics of Carbon Dioxide in Aqueous Blends of N-Methyldiethanolamine and L-Arginine Using the Stopped-Flow Technique
Authors: Mahmud Nafis , Benamor Abdelbaki , Nasser Mustafa , El-Naas Muftah H. , Tontiwachwuthikul Paitoon
Published: February 2019

Reduction of carbon dioxide emission from natural and industrial flue gases is paramount to help mitigate its effect on global warming. Efforts are continuously deployed worldwide to develop efficient technologies for CO2 capture. The use of environment friendly amino acids as rate promoters in the present amine systems has attracted the attention of many researchers recently. In this work, the reaction kinetics of carbon dioxide with blends of N-methyldiethanolamine and L-Arginine was investigated using stopped flow technique. The experiments were performed over a temperature range of 293 to 313 K and solution concentration up to one molar of different amino acid/amine ratios. The overall reaction rate constant (kov) was found to increase with increasing temperature and amine concentration as well as with increased proportion of L-Arginine concentration in the mixture. The experimental data were fitted to the zwitterion and termolecular mechanisms using a nonlinear regression technique with an average absolute deviation (AAD) of 7.6% and 8.0%, respectively. A comparative study of the promoting effect of L-Arginine with that of the effect of Glycine and DEA in MDEA blends showed that MDEA-Arginine blend exhibits faster reaction rate with CO2 with respect to MDEA-DEA blend, while the case was converse when compared to the MDEA-Glycine blend.
A Framework for the Development of Wetland for Agricultural Use in Indonesia
Authors: Sulaiman Andi Amran , Sulaeman Yiyi , Minasny Budiman
Published: February 2019

Crop production needs to double to feed the world’s growing population. Indonesia, as the fourth most populated country in the world, needs to meet its food security challenge with a shrinking arable land area. Indonesia has over 34 million ha of swampland. The scarcity of arable land in Indonesia means wetlands are likely to be converted to agricultural use. The challenge is to both profitably and sustainably do so. This paper presents a framework for developing wetlands for food production, which includes (1) the characterization of land and problem of development; (2) analysis of historical development and lessons learned; (3) technology development; and (4) optimization of development. We analyze each of the components and its relation to regional economic growth and lessons learned. For successful future wetland development, three factors must be considered: Land-soil-water characterization, landscape and land use design, and community development. This framework can be adopted by other tropical areas for the development of wetlands.
The Effect of Snow Depth on Spring Wildfires on the Hulunbuir from 2001–2018 Based on MODIS
Authors: Ying Hong , Shan Yu , Zhang Hongyan , Yuan Tao , Rihan Wu , Deng Guorong
Published: February 2019

Wildfires are one of the important disturbance factors in natural ecosystems and occur frequently around the world. Detailed research on the impact of wildfires is crucial not only for the development of livestock husbandry but also for the sustainable use of natural resources. In this study, based on the Moderate Resolution Imaging Spectroradiometer (MODIS) burned area product MC464A1 and site snow depth measurements, the kernel density estimation method (KDE), unary linear regression analysis, Sen + Mann-Kendall trend analysis, correlation analysis, and R/S analysis were used to evaluate the relationship between snow and spring wildfires (SWFs) in Hulunbuir. Our results indicated that SWFs decreased during the period of 2001–2018, were mainly distributed in the eastern portion of the study area, and that the highest SWF density was 7 events/km2. In contrast, the maximum snow depth increased during the period of 2001–2018 and the snow depth was deeper in the middle but shallower in the east and west. The SWFs and snow depth have significant negative correlations over space and time. The snow depth mainly affects the occurrence of SWFs indirectly by affecting the land surface temperature (LST) and Land Surface Water Index (LSWI) in spring. The snow depth was positively correlated with the LSWI in most of Hulunbuir and strongly negatively correlated with the LST, and this correlation was stronger in the eastern and western regions of Hulunbuir. The results of the Hurst exponent indicated that in the future, the snow depth trend will be opposite that of the current state, meaning that the trend of decreasing snow depth will increase dramatically in most of the study area, and SWFs may become more prominent. According to the validation results, the Hurst exponent is a reliable method for predicting the snow depth tendency. This research can be based on the snow conditions of the previous year to identify areas where fires are most likely to occur, enabling an improved and more targeted preparation for spring fire prevention. Additionally, the present study expands the theory and methods of wildfire occurrence research and promotes research on disasters and disaster chains.
Performance Improvement of a Fiber-Reinforced Polymer Bar for a Reinforced Sea Sand and Seawater Concrete Beam in the Serviceability Limit State
Authors: Jiang Jiafei , Luo Jie , Yu Jiangtao , Wang Zhichen
Published: February 2019

Fiber-reinforced polymer (FRP) has supreme resistance to corrosion and can be designed with optic fibers. FRP can be an alternative to steel reinforcement for concrete structures, and can serve as a sensor for smart concrete structures. Due to poor cracking control and bond performance, the limit of flexural capacity in the serviceability limit state has not been determined, which has obstructed the wider application of FRP bars in smart structures. In this study, in order to overcome these shortcomings, a new engineering cementitious composite (ECC) with superior tensile strain capacity was used to replace the cover around the FRP bars in the tensile zone. To investigate the anti-cracking performance of the new composite beam, seven simply supported beams were designed. In the preliminary investigation, the longitudinal FRP bars in these beams were designed without optic fibers to focus on the mechanical behavior. The beams were tested under four-point load and measured using the digital sensor technique, digital image correlation (DIC). The test results showed that introducing a new ECC layer on the tensile side improves the cracking control and flexural behavior (load capacity and deformability) of a FRP-reinforced sea sand and seawater concrete (SSC) beam, especially in the serviceability limit state. We demonstrate the new composite beam can steadily and fully improve the tensile capacity of FRP bars, which is the basis of using FRP bars as sensors.