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Oxygen sensing

D Tarade, M Ohh
Mutations in VHL underlie von Hippel-Lindau (VHL) disease, a hereditary cancer syndrome with several subtypes depending on the risk of developing certain combination of classic features, such as clear cell renal cell carcinoma (ccRCC), hemangioblastoma and pheochromocytoma. Although numerous potential substrates and functions of pVHL have been described over the past decade, the best-defined role of pVHL has remained as the negative regulator of the heterodimeric hypoxia-inducible factor (HIF) transcription factor via the oxygen-dependent ubiquitin-mediated degradation of HIF-α subunit...
September 18, 2017: Oncogene
Zong-Xuan Tong, Wei Liu, Hui Huang, Hong-Zong Chen, Xian-Jun Liu, Yong-Qing Kuang, Jian-Hui Jiang
6-(Diethylamino)-2,3-dihydro-1H-xanthene-4-carbaldehyde (DDXC), a reported synthetic intermediate for near-infrared fluorescent dyes, was developed into a fluorescent pH probe for extreme acidity. The unique sensing mechanism of DDXC for pH is based on the reversible protonation of the carbonyl oxygen followed by keto-enol tautomerization. The probe displays a linear ratiometric fluorescence response (I512/I580) to H(+) over the extremely acidic range of pH 2.0-4.0 with a pKa of 3.11, and features high fluorescence quantum yield (Φ = 0...
September 18, 2017: Analyst
Dongwei Ma, Benyuan Ma, Zhiwen Lu, Chaozheng He, Yanan Tang, Zhansheng Lu, Zongxian Yang
In this study, the interaction between gas molecules, including H2O, N2, CO, NO, NO2 and N2O, and a WSe2 monolayer containing an Se vacancy (denoted as VSe) has been theoretically studied. Theoretical results show that H2O and N2 molecules are highly prone to be physisorbed on the VSe surface. The presence of the Se vacancy can significantly enhance the sensing ability of the WSe2 monolayer toward H2O and N2 molecules. In contrast, CO and NO molecules highly prefer to be molecularly chemisorbed on the VSe surface with the non-oxygen atom occupying the Se vacancy site...
September 18, 2017: Physical Chemistry Chemical Physics: PCCP
Yuanqing Wei, Zhenzhen Wei, Peicheng Luo, Wei Wei, Songqin Liu
Photodynamic therapy (PDT) is an effective and promising method for cancer treatment, which is proposed for more than one century. However, the specific delivery of photosensitizer to target carcinoma cells to reduce the side effect is still a great challenge. This work provides a strategy to deliver photosensitizers to cancer cells by utilizing pH-sensitive polyethylene glycol metal-phenolic network (PEG-MPN) capsules to encapsulate haematoporphyrin monomethyl ether (HMME). With the assistance of folic acid (FA), HMME-doped PEG-MPN capsules (MPN@HMMEs) accumulate in carcinoma cells selectively followed by releasing HMME in the lysosomes because of the physiologically relevant acidic pH environment...
September 18, 2017: Artificial Cells, Nanomedicine, and Biotechnology
Yudong Xue, Govindhan Maduraiveeran, Mingyong Wang, Shili Zheng, Yi Zhang, Wei Jin
Owing to the extensive applications of hydrogen peroxide (H2O2) in biological, environmental and chemical engineering, it is of great importance to investigate sensitive and selective sensing platform towards the detection of H2O2. Herein, oxygen-implanted MoS2 nanoparticles decorated graphene nanocomposite is synthesized via a facile one-pot solvothermal method for the sensitive detection of H2O2 in alkaline media. The structure and morphology of the MoS2/graphene nanocomposites were systematically characterized, showing that Mo-O bonds are formed and oxygen is implanted into the crystal structure in the nanocomposite...
January 1, 2018: Talanta
Itay Algov, Jennifer Grushka, Raz Zarivach, Lital Alfonta
Flavin-adenine dinucleotide (FAD) dependent glucose dehydrogenase (GDH) is a thermostable, oxygen insensitive redox enzyme that has been widely used in bioelectrochemical applications. The FAD co-factor of the enzyme is buried within the proteinogenic matrix of the enzyme which makes it almost unreachable for a direct communication with an electrode. In the present study, FAD dependent glucose dehydrogenase was fused to a natural minimal cytochrome domain in its c-terminus to achieve direct electron transfer...
September 15, 2017: Journal of the American Chemical Society
P V Samir, Srinivas Namineni, P Sarada
PURPOSE: To assess the efficacy of nitrous oxide (N2O)-oxygen (O2) inhalation sedation by rapid induction technique using preadjusted mix of 30% N2O and 70% O2 in children. MATERIALS AND METHODS: Sixty children with a treatment plan which included pulp therapy were recruited for the study. Children categorized 3 and 4 of Frankl behavior rating scale and American Society of Anesthesiologists health status I and II were included for the study. Children were distributed into study group (Group-I) and control group (Group-II) by fishbowl randomization...
October 2017: Journal of the Indian Society of Pedodontics and Preventive Dentistry
Zhao-Feng Wu, Xiao-Ying Huang
Herein, the solvothermal preparations, crystal structures, and fluorescence properties of three Mg-Zn heterometallic coordination polymers (CPs), i.e. [Mg2Zn2(OH)2(1,4-NDC)3(H2O)2]·6H2O (1), [Mg1.13Zn1.87(1,4-NDC)3(dppe)(CH3OH)] (2), and [Mg1.17Zn1.83(1,4-NDC)3(py)2]·1.5py (3), based on the mixed ligands of 1,4-naphthalene dicarboxylic acid (1,4-H2NDC) and N-containing ligands of 1,3-di(4-pyridyl)propane (dppe) or pyridine (py) are presented. In the title compounds, Zn and Mg are statistically distributed, as confirmed by single crystal analysis, and the ratios of Zn and Mg have been identified by inductively coupled plasma (ICP) measurements...
September 14, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Alexandra W Fuller, Phoebe Young, B Daniel Pierce, Jamie Kitson-Finuff, Purvi Jain, Karl Schneider, Stephen Lazar, Olga Taran, Andrew G Palmer, David G Lynn
The rhizosphere, the narrow zone of soil around plant roots, is a complex network of interactions between plants, bacteria, and a variety of other organisms. The absolute dependence on host-derived signals, or xenognosins, to regulate critical developmental checkpoints for host commitment in the obligate parasitic plants provides a window into the rhizosphere's chemical dynamics. These sessile intruders use H2O2 in a process known as semagenesis to chemically modify the mature root surfaces of proximal host plants and generate p-benzoquinones (BQs)...
2017: PloS One
Eric F Kong, Christina Tsui, Sona Kucharíková, Patrick Van Dijck, Mary Ann Jabra-Rizk
In microbial biofilms, microorganisms utilize secreted signaling chemical molecules to coordinate their collective behavior. Farnesol is a quorum-sensing molecule secreted by the fungal species Candida albicans, shown to play a central physiological role during fungal biofilm growth. Our pervious in vitro and in vivo studies characterized an intricate interaction between C. albicans and the bacterial pathogen Staphylococcus aureus, as these species co-exist in biofilm. In this study, we aimed to investigate the impact of farnesol on S...
September 11, 2017: Antimicrobial Agents and Chemotherapy
Sangcheol Yoon, Hyebin Kim, Eun-Sol Shin, Jun Nyeong Huh, Yong-Young Noh, Byoungchoo Park, Inchan Hwang
High electrical conductivity of metal oxide thin films needs uniform surface coverage, which has been the issue for the thin films based on electrospun nanofibers (NFs) that have advantage over the sputtered/spin-coated films with respect to large surface area and mechanical flexibility. Herein, we investigated a reduction in the sheet resistance of electrospun indium tin oxide (ITO) NF films with improved surface coverage. We found that the surface coverage depends significantly on the electrospinnable polymer concentration in the precursor solutions, especially after post-hot-plate annealing following the infrared radiation furnace treatment...
September 19, 2017: ACS Applied Materials & Interfaces
José Trinidad Holguín-Momaca, Francisco Espinosa-Magaña, Wilber Antúnez-Flores, Sion Federico Olive-Méndez
A sensor based on random connections of single crystalline SnO<sub>2</sub> nanowires (NW) has been fabricated for ethanol detection. Crystal growth was achieved on r-cut sapphire substrates using the vapor-liquid-solid process and vapor transport technique. The NWs length of ~10 μm leads to the formation of several random node connections ensuring the electrical conduction between electrodes during sensing experiments. The samples were submitted to thermal treatments under a reducing atmosphere of H<sub>2</sub>/Ar, to generate oxygen vacancies at the surface of the NW...
September 11, 2017: Nanotechnology
Dong Liu, Leimiao Lin, Qiaofen Chen, Hongzhi Zhou, Jianmin Wu
Silicon nanowires/TiO2 (SiNWs/TiO2) array with core-shell nanostructure was created by sol-gel and drop-casting methods. The hybrid material displayed excellent sensing performance for CH4 detection at room temperature. The chemiresistor sensor has a linear response towards CH4 gas in 30 ~ 120 ppm range with a detection limit of 20 ppm, which is well below most of CH4 sensors reported before. The enhanced gas sensing performance at room temperature was attributed to the creation of heterojunctions that form a depletion layer at the interface of SiNWs and TiO2 layer...
September 11, 2017: ACS Sensors
Laura Osorio-Rico, Abel Santamaria, Sonia Galván-Arzate
Thallium (Tl(+)) is a ubiquitous natural trace metal considered as the most toxic among heavy metals. The ionic ratio of Tl(+) is similar to that of potassium (K(+)), therefore accounting for the replacement of the latter during enzymatic reactions. The principal organelle damaged after Tl(+) exposure is mitochondria. Studies on the mechanisms of Tl(+) include intrinsic pathways altered and changes in antiapoptotic and proapoptotic proteins, cytochrome c, and caspases. Oxidative damage pathways increase after Tl(+) exposure to produce reactive oxygen species (ROS), changes in physical properties of the cell membrane caused by lipid peroxidation, and concomitant activation of antioxidant mechanisms...
2017: Advances in Neurobiology
Ting Zhou, Hiroaki Matsunami
The advent of single-cell RNA-sequencing (RNA-Seq) technology has enabled transcriptome profiling of individual cells. Comprehensive gene expression analysis at the single-cell level has proven to be effective in characterizing the most fundamental aspects of cellular function and identity. This unbiased approach is revolutionary for small and/or heterogeneous tissues like oxygen-sensing cells in identifying key molecules. Here, we review the major methods of current single-cell RNA-Seq technology. We discuss how this technology has advanced the understanding of oxygen-sensing glomus cells in the carotid body and helped uncover novel oxygen-sensing cells and mechanisms in the mice olfactory system...
September 8, 2017: Cell and Tissue Research
Hanbyul Jin, Sungchul Jung, Junhyung Kim, Sanghyun Heo, Jaeik Lim, Wonsang Park, Hye Yong Chu, Franklin Bien, Kibog Park
We introduce a new type of multi-functional capacitive sensor that can sense several different external stimuli. It is fabricated only with polydimethylsiloxane (PDMS) films and silver nanowire electrodes by using selective oxygen plasma treatment method without photolithography and etching processes. Differently from the conventional single-capacitor multi-functional sensors, our new multi-functional sensor is composed of two vertically-stacked capacitors (dual-capacitor). The unique dual-capacitor structure can detect the type and strength of external stimuli including curvature, pressure, strain, and touch with clear distinction, and it can also detect the surface-normal directionality of curvature, pressure, and touch...
September 7, 2017: Scientific Reports
Laura Terraneo, Michele Samaja
Two antithetic terms, hypoxia and hyperoxia, i.e., insufficient and excess oxygen availability with respect to needs, are thought to trigger opposite responses in cells and tissues. This review aims at summarizing the molecular and cellular mechanisms underlying hypoxia and hyperoxia in brain and cerebral tissue, a context that may prove to be useful for characterizing not only several clinically relevant aspects, but also aspects related to the evolution of oxygen transport and use by the tissues. While the response to acute hypoxia/hyperoxia presumably recruits only a minor portion of the potentially involved cell machinery, focusing into chronic conditions, instead, enables to take into consideration a wider range of potential responses to oxygen-linked stress, spanning from metabolic to genic...
September 7, 2017: International Journal of Molecular Sciences
Ahtasham Raza, Helen E Colley, Elizabeth Baggaley, Igor V Sazanovich, Nicola H Green, Julia A Weinstein, Stanley W Botchway, Sheila MacNeil, John W Haycock
Solid tumours display varied oxygen levels and this characteristic can be exploited to develop new diagnostic tools to determine and exploit these variations. Oxygen is an efficient quencher of emission of many phosphorescent compounds, thus oxygen concentration could in many cases be derived directly from relative emission intensity and lifetime. In this study, we extend our previous work on phosphorescent, low molecular weight platinum(II) complex as an oxygen sensing probe to study the variation in oxygen concentration in a viable multicellular 3D human tumour model...
September 6, 2017: Scientific Reports
Margaret L Daly, Caroline Kerr, Christopher A DeRosa, Cassandra L Fraser
The optical properties of meta-alkoxy-substituted difluoroboron dibenzoylmethane dyes were investigated in solution and in the solid state. Meta-alkoxy substitution induced strong intramolecular charge transfer (ICT) from the oxygen-donating substituent to the halide and boron acceptors in the excited state, as compared to the π-π* transition that is observed with para-alkoxy substitution. The optical properties of para- and meta-substituted alkoxy boron dyes were evaluated by calculations, in dilute solution, and in solid-state films...
September 20, 2017: ACS Applied Materials & Interfaces
Antonín Brož, Lucie Bačáková, Pavla Štenclová, Alexander Kromka, Štěpán Potocký
Diamond nanoparticles, known as nanodiamonds (NDs), possess several medically significant properties. Having a tailorable and easily accessible surface gives them great potential for use in sensing and imaging applications and as a component of cell growth scaffolds. In this work we investigate in vitro interactions of human osteoblast-like SAOS-2 cells with four different groups of NDs, namely high-pressure high-temperature (HPHT) NDs (diameter 18-210 nm, oxygen-terminated), photoluminescent HPHT NDs (diameter 40 nm, oxygen-terminated), detonation NDs (diameter 5 nm, H-terminated), and the same detonation NDs further oxidized by annealing at 450 °C...
2017: Beilstein Journal of Nanotechnology
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