ARTICLE Download: 1| View: 3| Comments: 0 | doi:10.20944/preprints201910.0229.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: malignant melanoma; head and neck cancer; cancer stem cell; melanoma metastasis; induced pluripotent stem cell
Online: 19 October 2019 (17:15:36 CEST)
Cancer stem cells (CSCs) have been identified in many cancer types. This study identified and characterized CSCs in head and neck metastatic malignant melanoma (HNmMM) to regional lymph nodes using induced pluripotent stem cell (iPSC) markers. Immunohistochemical (IHC) staining performed on 20 HNmMM tissue samples demonstrated expression of iPSC markers OCT4, SOX2, KLF4 and c-MYC in all samples while NANOG was expressed at low levels in two samples. Immunofluorescence (IF) staining demonstrated an OCT4+/SOX2+/KLF4+/c-MYC+ CSC subpopulation within the tumor nests (TNs) and another within the peritumoral stroma (PTS) of HNmMM tissues. IF also showed expression of NANOG by some OCT4+/SOX2+/KLF4+/c-MYC+ cells within the TNs in an HNmMM tissue sample that expressed NANOG on IHC staining. In situ hybridization (n=6) and reverse-transcription quantitative polymerase chain reaction (n=5) on the HNmMM samples confirmed expression of all five iPSC markers. Western blotting of four primary cell lines derived from four of the 20 HNmMM tissue samples showed expression of SOX2, KLF4, and c-MYC but not OCT4 and NANOG, and three of these cell lines formed tumorspheres in vitro. We demonstrate the presence of two putative CSC subpopulations within HNmMM, which may be a novel therapeutic target in the treatment of this aggressive cancer.
ARTICLE Download: 0| View: 4| Comments: 0 | doi:10.20944/preprints201910.0228.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: TiO2 nanorods; water splitting; photoelectrocatalyst; sacrificial agent; one-pot hydrothermal
Online: 19 October 2019 (17:04:29 CEST)
Photoelectrocatalytic water splitting by using various TiO2 nanostructures is a promising approach to generate hydrogen without harmful byproducts. However, their effective performance is restricted by some drawbacks such as high rapid electron-hole pair recombination and backward reaction producing H2O. Thus in this study, the probability of enhancing hydrogen generation rate by adding methanol as a sacrificial agent to the anodic chamber of a two-compartment photoelectrochemical cell is investigated. Herein, one-dimensional elongated TiO2 nanorods that were fabricated via a facile one-pot hydrothermal method are utilized as potent photoanode. Voltammetric characterizations confirm that addition of alcoholic sacrificial agent has a significant effect on photoelectrochemical properties of TiO2 nanorods which by adding 10 wt% of methanol, the photocurrent density and photoconversion efficiency increased from 0.8mA.cm-2 to 1.5mA.cm-2 and from 0.28% to 0.45%, respectively. The results of photoelectrocatalytic water splitting indicated that the hydrogen generation rate in the presence of methanol was about 1.2 times higher than that from pure water splitting. These enhancements can be attributed to the key role of methanol. Methanol molecules not only inhibit the electron-hole pair recombination but also accelerate the hydrogen generation rate by sharing their hydrogen atoms.
ARTICLE Download: 1| View: 4| Comments: 0 | doi:10.20944/preprints201910.0227.v1
Subject: Earth Sciences, Oceanography Keywords: lagrangian drifter; rafos floats; empirical model decomposition (emd); deterministic-stochastic emd; intrinsic mode function (imf); eddy radial scale; eddy velocity scale; eddy rossby number; eddy-current kinetic energy ratio
Online: 19 October 2019 (16:41:37 CEST)
Deterministic-stochastic empirical mode decomposition (EMD) is used to obtain low-frequency (non-diffusive, i.e., background velocity) and high-frequency (diffusive, i.e., eddies) components from a Lagrangian drifter‘s trajectory. Eddy characteristics are determined from the time series of eddy trajectories from individual Lagrangian drifter such as the eddy radial scale, eddy velocity scale, eddy Rossby number, and eddy-background kinetic energy ratio. A long-term dataset of the SOund Fixing And Ranging float time series obtained near the California coast by the Naval Postgraduate School from 1992 to 2004 at depth between 150 and 600 m (http://www.oc.nps.edu/npsRAFOS/) is used as an example to demonstrate the capability of the deterministic-stochastic EMD.
REVIEW Download: 0| View: 3| Comments: 0 | doi:10.20944/preprints201910.0226.v1
Subject: Materials Science, Metallurgy Keywords: friction stir welding; TIG welding; friction stir processing; dissimilar alloys; aluminium alloys; mechanical properties; microstructure
Online: 19 October 2019 (16:22:20 CEST)
The use of aluminium alloys continues to grow in many applications to mention a few aerospace, automotive, electronics, electricity, construction and food packaging. With so much demand there is a new interest in welding of dissimilar aluminium alloys. Some of the welding techniques used to join dissimilar aluminium alloys include friction stir welding and TIG welding. The welding of dissimilar alloys affects the mechanical properties negatively due to porosity and cracking during the welding. This then suggests that there should be a process which can be used to improve the dissimilar alloys mechanical properties post its production. Friction stir processing was found to be one of the mechanical techniques that could be used to improve the mechanical properties of the material. This paper reports on the literature on the friction stir welding, TIG welding and friction stir processing techniques published so far, with the aim to identify the gap in the use of friction stir process as a post processing technique of the weld joints.
REVIEW Download: 0| View: 4| Comments: 0
Subject: Medicine & Pharmacology, Nursing & Health Studies Keywords: cancer; chemotherapy; nausea; vomiting; progressive muscle relaxation
Online: 19 October 2019 (16:11:44 CEST)
(1) Background: Previous systematic review suggested a beneficial effect of progressive muscle relaxation (PMR) for cancer patients receiving chemotherapy. However, poor quality of eligible studies impaired the reliability and validity of findings. Moreover, additional potential studies with good quality published in Chinese language have been published recently. The aim of the present systematic review was to investigate the value of PMR training in preventing and alleviating nausea and vomiting caused by chemotherapy among cancer patients. (2) Methods: We assigned two independent investigators to search all potential studies in PubMed, Cochrane Controlled Register of Trial (CENTRAL), Cumulative Index to Nursing and Allied Health Literature (CINAHL), China Biomedical Literature database (CBM), China National Knowledge Infrastructure (CNKI), and Wanfang data. We used data extraction sheet extracted all essential information, and used the Cochrane risk of bias assessment tool to appraise the quality of eligible studies. Finally, we qualitatively summarized the results of all included studies. (3) Results: Six studies enrolling 288 patients were considered to meet our selection criteria finally. Of these 6 studies, three were labeled as moderate quality, and the remaining studies were low quality. All included studies consistently suggested that PMR has a positive impact on nausea and vomiting caused by chemotherapy among cancer patients especially alleviating the incidence, frequency and degree of delayed nausea and vomiting. (4) Conclusions: Independent studies indicated that PMR was a beneficial approach to prevent and alleviate nausea and vomiting caused by chemotherapy among cancer patients. However, further studies considering other types of primary tumors should be designed in order to increase the generality of PMR because studies included in the present systematic review mainly enrolled lung cancer and breast cancer.
ARTICLE Download: 2| View: 16| Comments: 0 | doi:10.20944/preprints201910.0223.v1
Subject: Life Sciences, Biochemistry Keywords: α-glucosidase; glyceollin; genistein; luteolin; daidzein; phytoalexins; enzyme kinetics; combination index
Online: 19 October 2019 (02:20:45 CEST)
To determine the mode of action of the effects of phytoalexins in soybeans, we analyzed enzyme inhibition kinetics using Michaelis–Menten plots and the Lineweaver–Burk plots. The results showed that glyceollin showed competitive inhibition, genistein showed noncompetitive, daidzein was uncompetitive, and luteolin showed a mixed mode of action. The Ki values were determined using a Dixon plot as: glyceollin, 18.99; genistein, 15.42; luteolin, 16.81; and daidzein, 9.99 μM, respectively. Furthermore, potential synergistic effects between glyceollin and the three designated polyphenols were investigated. A combination of glyceollin and luteolin (the ratio of 3:7 of glyceollin and luteolin) had synergistic effects on α-glucosidase inhibition according to combination index (CI)-isobologram equation. Collectively, these results showed that a combination of glyceollin and luteolin has the potential to inhibit α-glucosidase activity via a synergistic mode of action.
ARTICLE Download: 4| View: 16| Comments: 0 | doi:10.20944/preprints201910.0222.v1
Subject: Engineering, Other Keywords: 3D structure; gradient foam; additive manufacturing; CO2 foaming; copolymer
Online: 19 October 2019 (02:10:29 CEST)
Synthetic polymer-based gradient foams have considered as promising category of functionally graded materials with unique properties. In this study, the carbon dioxide (CO2) foaming technology has used for PET-PEN (Polyethylene Terephthalate - Polyethylene Naphthalate) copolymer towards porous functional materials with thermal insulation with reasonable mechanical strength. Through scanning electron microscope based morphological characterization, a potential to fabricate gradient foam structures with micro-pores has identified. It has shown that variation of post-foaming temperature can tune the pore size distribution although the very high post-foaming temperature tends to cause structural instability. Thermal measurement data set the limits of operation, confirmed by simultaneous differential scanning calorimeter and thermo-gravimetric analysis. Mechanical stress and thermal conductivity also has measured to find rationale of thermal insulation with reasonable mechanical strength and to elucidate the actual 3D grid foam of copolymer.
ARTICLE Download: 4| View: 22| Comments: 0
Subject: Chemistry, Organic Chemistry Keywords: secondary metabolites; microbial diversity; metabolomics; molecular network; marine bacteria
Online: 19 October 2019 (02:01:18 CEST)
Rocas Atoll is a unique environment in the Equatorial Atlantic Ocean, hosting a large number of endemic species and studies on the chemical diversity emerging from this biota are rather scarce. Therefore, the present work aims to assess the metabolomic diversity and pharmacological potential of the microbiota from Rocas Atoll. A total of 76 bacteria were isolated and cultured in liquid culture media to obtain crude extracts. About one third (34%) of these extracts were considered cytotoxic against human colon adenocarcinoma HCT-116 cell line. 16S rRNA gene sequencing analysis revealed that the bacteria producing cytotoxic extracts are mainly from the Actinobacteria phylum, including Streptomyces, Salinispora, Nocardiopsis and Brevibacterium genera, and in a smaller proportion from Firmicutes phylum (Bacillus). The search in the GNPS spectral library unveiled a high chemodiversity being produced by these bacteria, including rifamycins, antimycins, desferrioxamines, ferrioxamines, surfactins, surugamides, staurosporine and saliniketals, along with several unidentified compounds. Using an original approach, molecular network successfully highlighted groups of compounds responsible for the cytotoxicity of crude extracts. DEREPLICATOR+, a recently developed in silico tool (GNPS), allowed the identification of derivatives of the macrolide novonestimycin, as the cytotoxic compounds into the extracts produced by Streptomyces BRB-298 and BRB-302. Overall, these results highlighted the pharmacological potential of bacteria from this singular Atoll.
ARTICLE Download: 1| View: 13| Comments: 0 | doi:10.20944/preprints201910.0220.v1
Subject: Keywords: electron; topology; magnetic flux quantization; charge; mass; electroweak theory; Bohr’s energy; W boson vector
Online: 19 October 2019 (01:51:16 CEST)
A topological quantum interplay between the magnetic flux and the mass has been investigated, for the case of an electron, by evaluating a gauge-invariant phase factor (a Wilson loop) linked to the electromagnetic gauge field of the particle. In particular, from this phase factor and the quantization of the magnetic flux variations, a relationship between the mass at rest of the electron and its self-energy , arising from radiative corrections, has been obtained also within a QED approach. Besides, a formulation of an energy scale comparable to the energy at rest of an electron-positron pair is proposed. Remarkably, a reckoning of the Bohr energy of a W+ W- pair is compatible with constants and parameters usually employed within the electroweak theory and comparable to the energy at rest of an electron-positron pair.