Metal Related Nanoparticles\u27 Physical Behaviors in Different Physiologica Environments

In the past decades, the development of nanotechnology has had tremendous successes in material science. In this technology, the pertinent materials are used at the intermediate scale between individual molecules and their size in the nanometer region(1-100nm) compared to bulk materials. This nanoscale size provides a larger surface area; therefore, nanoparticles would be perfect essential components of nanotechnology. The reduced size of nanoparticles has a larger surface ratio to volume, which can modify their chemical, mechanical, structural, and electrical properties. In this study, the main goal is to test different metal related nanoparticles, such as CuNPs (Copper nanoparticles), FeNPs (Iron nanoparticles), CuHARS (Copper high-aspect ratio structure) and, Zn (Zinc microparticles) with different biological environments. In specific biological environments, such as sterilized water, deionized water, and various cell culture media, nanoparticles will change their morphology in different degrees; also, in living cells (astrocyte and CRL rat brain glioma cells) environment these nanoparticles either damage the cells or would not harm the cells. The hypothesis of this project is that CuHARS or CuNPs under biological conditions would degrade. In order to prove this hypothesis as valid, CuHARS with CuNPs were tested in sterilized water and cell culture media at room temperature and body temperature. The result showed that CuHARS and CuNPs will degrade in cell culture media at room temperature and body temperature at different pace. Surprisingly, CuHARS and CuNPs in sterilized water are aggregated in different levels. Charges around the nanoparticles cause them to aggregate or evenly disperse in water, but they do not degrade. After the testing, image analysis methods were used to extrapolate nanoparticles as either aggregating, degrading, or more stable. After testing FeNPs in astrocyte cells and CRL rat brain glioma cancer cells, the hypothesis was that FeNPs would not affect morphology of the cells. Results showed that astrocyte and CRL rat brain glioma cancer cells were not damaged and were healthy. However, other nanoparticles, such as CuNPs and, CuHARS have toxicity by nature, they harmed the normal astrocyte and CRL rat brain glioma cancer cells

Luteolin attenuates high glucose-induced cytotoxicity by suppressing TXNIP expression in neuronal cells

Purpose: To determine the potential effect of luteolin in neuroprotection using an in vitro model of diabetic neuropathy (DN) in PC12 cells by high glucose (HG)-induced neurotoxicity. Methods: PC12 cells were pretreated with HG media for 3, 6, 12, and 24 h, followed by treatment with increasing concentrations of luteolin (10, 25, and 50 ug/ml) for 24 hours. Following luteolin treatment, the cells were transfected with a plasmid expressing thioredoxin-interacting protein (TXNIP). To evaluate HG-induced cytotoxicity, the expression levels of the inflammatory markers interleukin (IL)-8, IL-6, and tumor necrosis factor-α (TNF-α) were evaluated by quantitative reverse transcription PCR (qRT-PCR) and ELISA. In addition, the apoptotic cells were assessed by flow cytometry. The expression levels of TXNIP protein and mRNA were determined by western blotting and qRT-PCR, respectively. Results: Luteolin decreased the expression levels of TNF-α, IL-1β, and IL-6 in a dose-dependent manner at both the protein and mRNA level. Luteolin also decreased HG-induced apoptosis in PC12 cells (p < 0.05). The expression of B-cell lymphoma 2 (BCL-2) was suppressed, whereas those of cleaved PARP and cleaved caspase-3 were increased following HG treatment. Luteolin treatment had the opposite effect in a dose-dependent manner (p < 0.05). Luteolin reduced HG-induced inflammation and apoptosis in PC12 cells by inhibiting TXNIP expression (p < 0.05). Conclusion: These data indicate that the neuroprotective effects of luteolin is probably exerted its antiapoptotic and anti-inflammatory activities via the TXNIP pathway

Research on Establishment of Abnormal Phlegmatic Syndrome with Premature Ovarian Failure Rat Model and Effects of Balgham Munziq Treatment

This study aimed to establish and explore the biological basis of abnormal phlegmatic syndrome with premature ovarian failure (POF) model in rats based on the Uighur medicine (UM) in the first place and investigate the effects of unique herbal medicine, Balgham Munziq (BMq). Mature female Wistar rats were fed with spinach and coriander in cold and humid condition for approximately 20 weeks until abnormal phlegmatic syndrome (APS) model was established. When APS model was confirmed by Uighur medical experts, APS with POF disease rats were subdivided into APS with POF disease model group and APS with POF disease treated with BMq group; the rest of them were subdivided into APS model group and APS treated with BMq group. The results show that biological characteristics of animals in the course of modeling period were in accordance with clinical features of abnormal phlegmatic syndrome (APS) in Uighur medicine. Herbal medicine BMq not only reverted reproductive hormone levels disorders but also improved the function of hypothalamic-pituitary-ovarian axis and regulated secretion of monoamine neurotransmitters. APS is most likely to cause pathological changes of hypothalamic-pituitary-ovarian axis and lead to the occurrence of POF and BMq is effective in the treatment of APS with POF disease

Development of fermented sea buckthorn (Hippophae rhamnoides L.) juice and investigation of its antioxidant and antimicrobial activity

Sea buckthorn (Hippophae rhamnoides L.) is an edible and medicinal plant species. However, due to its sour taste, it is not readily accepted by consumers. To overcome this, fermentation can be used to change its flavor profile. In this study, we used response surface methodology (RSM) to determine the best process for producing fermented sea buckthorn juice (FSBJ) using probiotics. The biological enzyme activity and total flavonoid content (TFC) of sea buckthorn juice (SBJ) increased after fermentation. When the number of bacteria inoculated was 4.08 × 106 CFU/mL and the inoculation ratio was 30% Z. mobilis, 5% L. casei, 13.75% L. plantarum, 31.25% P. acidilactici, 12.5% L. animalis, and 7.5% P. pentosaceus, the amount of sugar was 2.98% (w/v) after 20 h of fermentation at 37°C, and the superoxide dismutase (SOD) activity reached 725.44 U/mL, and the TFC reached 2.38 mg/mL. FSBJ demonstrated strong antimicrobial activity against Escherichia coli, Staphylococcus aureus and Botrytis cinerea. Then, to investigate the antioxidant capacity of FSBJ, we used H2O2 to induce oxidative stress in C2C12 cells and assessed the protection conferred by FSBJ to damaged cells. It was discovered that after 24 h of treatment with FSBJ, not only was there an increase in the activities of intracellular SOD and glutathione peroxidase (GSH-Px), but also a reduction in reactive oxygen species (ROS) content, catalase (CAT) activity, and malondialdehyde (MDA) content. This research lays the theoretical groundwork and provides reference materials for the improved fermentation of sea buckthorn and demonstrates its resulting antioxidant effect

Anti-Inflammatory ent-Kaurane Diterpenoids from Isodon serra

Ten new ent-kaurane diterpenoids, including two pairs of epimers 1/2 and 4/5 and a 6,7-seco-ent-kauranoid 10, were obtained from the aerial parts of Isodon serra. The structures of the new compounds were confirmed by extensive spectroscopic methods and electronic circular dichroism (ECD) data analysis. An anti-inflammatory assay was applied to evaluate their nitric oxide (NO) inhibitory activities by using LPS-stimulated BV-2 cells. Compounds 1 and 9 exhibited notable NO production inhibition with IC50 values of 15.6 and 7.3 μM, respectively. Moreover, the interactions of some bioactive diterpenoids with inducible nitric oxide synthase (iNOS) were explored by employing molecular docking studies.https://pubs.acs.org/journal/jnprdf2021-09-29hj2021Plant Production and Soil Scienc

Diterpenoids from the leaves of Casearia kurzii showing cytotoxic activities

A phytochemical investigation to obtain bioactive substances as lead compounds or agents for cancer led to the obtainment of six new and two known clerodane diterpenoids from the leaves of Casearia kurzii. Their structures were elucidated using NMR techniques and electronic circular dichroism (ECD) calculations. The subsequent biological cytotoxicity evaluation of these isolates toward human lung cancer A549, human cervical cancer HeLa, human chronic myeloid leukemia K562, and human hepatocellular carcinoma HepG2 was carried out. The most active compound 4 with an IC50 value of 9.7 μM against HepG2 cells was selected to examine the cytotoxic mechanism, which induced the apoptosis and arrested the HepG2 cell cycle at S stage. The in vivo zebrafish experiments revealed that compound 4 had the property of inhibiting tumor proliferation and migration.The National Key Research and Development Program of China, the National Natural Science Foundation of China, Hundred Young Academic Leaders Program of Nankai University, the Natural Science Foundation of Tianjin, State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources and the open project of Key Laboratory of Xinjiang Uygur Autonomous Region.http://www.elsevier.com/ locate/bmclhj2021Plant Production and Soil Scienc

Power Scaling of Single-Mode Ytterbium and Erbium High-Power Fiber Lasers

Power scaling of rare-earth-doped fiber lasers is vital to many emerging applications. Average output power scaling with Yb doped fiber lasers operating near 1.1 μm was very successful in the 10 years between 2000 and 2010. The discovery and rediscovery of many limiting factors such as nonlinear effects, thermal lensing, optical damage, and so forth showed various bottlenecks in further power scaling of output power from a single fiber. On the other hand, single-mode average output power scaling of fiber lasers operating at ~980 nm and ~1560 nm has lagged much behind their pioneering counterparts at ~1.1 μm. Single-mode high-power fiber lasers at these scarce wavelengths are in great demand for many applications such as pumping ultrafast lasers, nonlinear frequency conversion, lidar, free-space optical communication, etc. However, currently, commercial single-mode laser didoes at ~980 nm have very limited output power of near 1 W. Many different types of Yb-doped fibers for ~980 nm lasers were reported previously but the record output power has only reached to ~15 W from a monolithic single-mode Yb fiber laser. One of the major limiting factors is the amplified spontaneous emission (ASE) at ~1030 nm which has a net positive gain at very low inversion (\u3e5%) while Yb laser operation at ~980 nm needs very high inversion (\u3e50%). In the first part of this dissertation, we propose the utilization of a Yb-doped multiple cladding resonance (MCR) based all-solid photonic bandgap fiber (AS-PBF) for power scaling of single-mode laser operating at ~980 nm. This novel type of AS-PBF provides three major advantages, including large core to cladding ratio, superior HOM suppression, and built-in wavelength filtering to suppress ASE at ~1030 nm. We have experimentally explored the power scaling of ~980 nm Yb fiber laser pumped at 915 nm. An optimized Yb PBF with 24 μm core and 130 μm cladding was fabricated after several fine-tuning processes of fiber dimensions (thus bandgap positions) by carefully characterizing the Yb AS-PBF and analyzing the output diagnostics of the laser oscillator. Eventually, we were able to obtain a near-diffraction-limited laser output with ~150 W from an all-fiber Yb fiber laser operating at ~980 nm, which represents a factor of 15 improvement over the previously reported record. This monolithic fiber laser demonstrates the potential of building a compact and robust commercial high-power single-mode fiber laser operating at ~980 nm. Additionally, it shows the potential of MCR AS-PBF to be incorporated in many other fibers for power scaling of fiber lasers at other wavelengths. In the second part of this dissertation, we explore the power scaling of single-mode fiber lasers operating at ~1.5-1.6 μm using Er/Yb co-doped LMA fibers. Due to its good atmospheric transmission and “eye-safe” nature of single-mode fiber lasers operating at this wavelength range, there is a growing demand for applications in many areas such as pumping Tm fiber lasers, CW coherent lidar, free-space optical communication, remote sensing, etc. Yb-free Er-doped fibers are another option to generate lasers at this wavelength, but further power scaling is limited due to low pump absorption cross section of Er fiber at ~980 nm. On the other hand, co-doping with Yb enables a factor 100 increase in pump absorption (10× from higher absorption cross section and 10× from higher maximum doping level) thus shortens effective fiber length. There are two major limiting factors for power scaling with Er/Yb co-doped fiber laser, including Yb→Er energy transfer bottleneck and excessive heat load due to large quantum defect. The former leads to strong Yb ASE (or parasitic lasing) at ~1.06 μm at certain threshold pump powers and will eventually clamp output power at ~1.6μm when the pumping rate exceeds the energy transfer rate. However, the working principle regarding the ASE threshold and output power clamping was not well understood as conventional models assume that all Yb-ions are equally responsible for Yb→Er energy transfer. The new model proposed in this dissertation is based on two types Yb ions, including coupled Yb ions and isolated Yb ions. The numerical simulations results show perfect agreement with experimental results, and it can predict and explain all the observed behaviors very well. We have also carried out a detailed experimental study on a master oscillator power amplifier (MOPA) using a commercial Er/Yb fiber (LMA-EYDF-25P/300-HE), which was counter pumped by kW-level multi-mode pump diode at 915nm. The achieved record single-mode output power of 302W was not limited by ASE (i.e. energy transfer bottleneck) but by fiber fuse in our case. Further analysis of MOPA output diagnostics and Er/Yb fiber parameters shows that lower Yb to Er ions ratio and pumping at a shorter wavelength (915 nm or 940 nm) played a major role in better ASE suppression, i.e high Yb ASE threshold power. Finally, we conclude that the energy transfer bottleneck will eventually come in with any Er/Yb fiber albeit at a much higher threshold pump power depending on how well the Er/Yb fiber is optimized. In the third part which is also the last part of this dissertation, we report our preliminary experimental results for power scaling of 1064 nm high-power single-frequency Yb fiber laser system based on a 976 nm counter-pumped MOPA configuration. There are two main limiting factors in this case, including SBS and TMI. Utilizing an LMA fiber could mitigate SBS by lowering laser intensity in the core, but the large core also leads to a low TMI threshold due to the excitation of HOMs. We propose to incorporate the previously studied MCR AS-PBF design into a new Yb AS-PBF with ~56 μm core and ~401 μm cladding, which expected to have a high SBS threshold above 1 kW. The preliminary experimental results show that single-frequency output power reaches ~500W before the onset of TMI. Also, the MOPA output does not show any signs of SBS indicated by careful characterizations such as backward power, spectrum, and linewidth measurement

Effet de l'environnement sur les propriétés électroniques et magnétiques de complexes de métaux de transition et de terres rares

This thesis presents the results of low-temperature scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) studies on transition-metal phthalocyanines molecules on the noble metal surfaces. The STM/STS measurements have been performed for MnPc and CuPc molecules adsorbed on Ag(111) and Au(111) surfaces at the experimental working temperature of 4.5 K. These two types of molecules exhibit substantially different adsorption configurations, the electronic and magnetic behaviors and the molecule vibrational structures. The STM/STS studies have focused mainly on the magnetic properties of these molecules by means of Kondo effect, and special attention has been paid to MnPc molecule due to its more interesting magnetic behavior arising from the central Mn atom. Particularly we investigated the spectral evolution of electronic and magnetic structures of MnPc starting from a single molecule up to the ordered bilayer structures on Ag(111) surface. In addition, the STM/STS investigations showed an evidence of magnetic coupling between the magnetic moments of the Co atom and MnPc molecule and its strong dependence on the adsorption site of Co atom. These STM/STS investigations on this system allowed us to understand the effect of molecule-substrate, molecule-molecule and molecule-atom interactions on the electronic and magnetic properties of MnPc molecules.Cette thèse présente les résultats de mesures expérimentales effectués à basse température par les techniques de microscopie tunnel à balayage et de spectroscopie par tunnel à balayage (STS) sur les métaux de transitions phthalocyanines déposées sur les surfaces de métaux nobles. Les mesures STM/STS ont été effectuées pour les molécules MnPc et CuPc adsorbées sur les surfaces Ag (111) et Au (111) à la température expérimentale de travail de 4,5 K. Ces deux types de molécules présentent une différence substantielle de configurations d'adsorption, des comportements électroniques et magnétiques et des structures vibratoires moléculaire. Les études STM/STS ont principalement porté sur les propriétés magnétiques de ces molécules à travers l’effet Kondo et une attention particulière a été accordée à la molécule de MnPc en raison de son comportement magnétique plus intéressant issu de l'atome Mn central. Particulièrement, nous avons étudié l'évolution spectrale des structures électroniques et magnétiques du MnPc partant d'une molécule unique jusqu'à la structure bicouche ordonnée sur la surface Ag (111). En outre, les études STM/STS ont montré une preuve de couplage magnétique entre les moments magnétiques de l'atome de Co et de la molécule de MnPc ainsi que sa forte dépendance vis-à-vis du site d'adsorption de l'atome de Co. Ces études STM/STS sur ce système nous ont permis de comprendre l'effet des interactions molécule-substrat, molécule-molécule et molécules-atome sur les propriétés électroniques et magnétiques des molécules de MnPc