“[12]Mercuracarborand-4”, the First Representative of a New Class of Rigid Macrocyclic Electrophiles: The Chloride Ion Complex of a Charge-Reversed Analogue of[12]Crown-4

1991 ◽  
Vol 30 (11) ◽  
pp. 1507-1508 ◽  
Author(s):  
Xiaoguang Yang ◽  
Carolyn B. Knobler ◽  
M. Frederick Hawthorne
Keyword(s):  
Chloride Ion ◽  
New Class ◽  
A Charge

Photo-Degradation of Methamidophos (An Insecticide) in Water Using Dye-Modified Nano-Crystalline TiO2 Supported onto Activated Carbon Surfaces

2020 ◽  
Vol 8 (2) ◽  
pp. 100-111
Author(s):  
Lamees Majad ◽  
Nidal Zatar ◽  
Sameer Amereih ◽  
Hikmat Hilal
Keyword(s):  
Activated Carbon ◽  
Uv Degradation ◽  
Photo Degradation ◽  
New Class ◽  
Nano Crystalline ◽  
Catalytic Sites ◽  
Modified Surfaces ◽  
Significant Temperature ◽  
A Charge ◽  
Catalyst Efficiency

Anatase TiO2 surfaces have been treated with 2, 4, 6-triphenylpyrylium hydrogen sulfate (TPPHS) or tripyridylporhpyrinatomanganese(II) (MnP) dyes to yield the modified TiO2/ dye surfaces. The modified TiO2/dye surface was then supported onto activated carbon (AC) surfaces to yield a new class of catalytic system AC/TiO2/dye. The catalytic activities of naked TiO2, dye solution, TiO2/dye, and AC/TiO2/dye systems were examined in photo-degradation of Methamidophos (insecticide) in water, using both UV and visible light. All examined systems showed catalytic activity when used either in the UV or the visible regions, but the AC/TiO2/ dye showed the highest activity. The dye role, in enhancing activity of modified surfaces in UV degradation of the examined contaminants, is understandable by a charge-transfer catalytic effect. AC role can be explained by its ability to adsorb contaminant molecules and bringing them closer to catalytic sites. There was no significant temperature effect on catalyst efficiency in Methamidophos photo-degradation. Oxygen is essential for semiconductor photocatalytic degradation of Methamidophos, but higher oxygen concentrations lead to a downturn of the reaction rate.

scholarly journals Cryo-EM structure of a proton-activated chloride channel TMEM206

2021 ◽  
Vol 7 (9) ◽  
pp. eabe5983
Author(s):  
Zengqin Deng ◽  
Yonghui Zhao ◽  
Jing Feng ◽  
Jingying Zhang ◽  
Haiyan Zhao ◽  
...  
Keyword(s):  
Chloride Channel ◽  
Chloride Channels ◽  
Ion Selectivity ◽  
Chloride Ion ◽  
Transmembrane Segments ◽  
New Class ◽  
The Core ◽  
Cryo Electron Microscopy ◽  
Extracellular Region ◽  
Evolutionarily Conserved

TMEM206 has been recently identified as an evolutionarily conserved chloride channel that underlies ubiquitously expressed, proton-activated, outwardly rectifying anion currents. Here, we report the cryo–electron microscopy structure of pufferfish TMEM206, which forms a trimeric channel, with each subunit comprising two transmembrane segments and a large extracellular domain. An ample vestibule in the extracellular region is accessible laterally from the three side portals. The central pore contains multiple constrictions. A conserved lysine residue near the cytoplasmic end of the inner helix forms the presumed chloride ion selectivity filter. Unprecedentedly, the core structure and assembly closely resemble those of the epithelial sodium channel/degenerin family of sodium channels that are unrelated in amino acid sequence and conduct cations instead of anions. Together with electrophysiology, this work provides insights into ion conduction and gating for a new class of chloride channels that is architecturally distinct from previously characterized chloride channel families.

scholarly journals Cryo-EM structure of a proton-activated chloride channel TMEM206

2020 ◽  
Author(s):  
Zengqin Deng ◽  
Yonghui Zhao ◽  
Jing Feng ◽  
Jingying Zhang ◽  
Haiyan Zhao ◽  
...  
Keyword(s):  
Chloride Channel ◽  
Chloride Channels ◽  
Ion Selectivity ◽  
Chloride Ion ◽  
Ion Conduction ◽  
Transmembrane Segments ◽  
New Class ◽  
Cryo Electron Microscopy ◽  
Extracellular Region ◽  
Evolutionarily Conserved

AbstractTMEM206 has been recently identified as an evolutionarily conserved chloride channel that underlies ubiquitously expressed, proton-activated, outwardly rectifying anion currents. Here we report the cryo-electron microscopy structure of pufferfish TMEM206, which forms a trimeric channel, with each subunit comprising two transmembrane segments, the outer and inner helices, and a large extracellular domain. An ample vestibule in the extracellular region is accessible laterally from the three side portals. The central pore contains multiple constrictions preventing ion conduction. A conserved lysine residue near the cytoplasmic end of the inner helix forms the presumed chloride ion selectivity filter. Unprecedentedly, the core structure and assembly closely resemble those of the epithelial sodium channel/degenerin family of sodium channels that are unrelated in amino acid sequence and conduct cations instead of anions. Together with electrophysiology, this work provides insights into ion conduction and gating for a new class of chloride channels that is architecturally distinct from previously characterized chloride channel families.

Photo-Degradation of Methamidophos (An Insecticide) in Water Using Dye-Modified Nano-Crystalline TiO2 Supported onto Activated Carbon Surfaces

2020 ◽  
Vol 8 (2) ◽  
pp. 100-111
Author(s):  
Lamees Majad ◽  
Nidal Zatar ◽  
Sameer Amereih ◽  
Hikmat Hilal
Keyword(s):  
Activated Carbon ◽  
Uv Degradation ◽  
Photo Degradation ◽  
New Class ◽  
Nano Crystalline ◽  
Catalytic Sites ◽  
Modified Surfaces ◽  
Significant Temperature ◽  
A Charge ◽  
Catalyst Efficiency

Anatase TiO2 surfaces have been treated with 2, 4, 6-triphenylpyrylium hydrogen sulfate (TPPHS) or tripyridylporhpyrinatomanganese(II) (MnP) dyes to yield the modified TiO2/ dye surfaces. The modified TiO2/dye surface was then supported onto activated carbon (AC) surfaces to yield a new class of catalytic system AC/TiO2/dye. The catalytic activities of naked TiO2, dye solution, TiO2/dye, and AC/TiO2/dye systems were examined in photo-degradation of Methamidophos (insecticide) in water, using both UV and visible light. All examined systems showed catalytic activity when used either in the UV or the visible regions, but the AC/TiO2/ dye showed the highest activity. The dye role, in enhancing activity of modified surfaces in UV degradation of the examined contaminants, is understandable by a charge-transfer catalytic effect. AC role can be explained by its ability to adsorb contaminant molecules and bringing them closer to catalytic sites. There was no significant temperature effect on catalyst efficiency in Methamidophos photo-degradation. Oxygen is essential for semiconductor photocatalytic degradation of Methamidophos, but higher oxygen concentrations lead to a downturn of the reaction rate.

A charge-switchable, four-armed polymeric photosensitizer for photodynamic cancer therapy

2014 ◽  
Vol 50 (33) ◽  
pp. 4354-4357 ◽  
Author(s):  
Chung-Sung Lee ◽  
Wooram Park ◽  
Young Um Jo ◽  
Kun Na
Keyword(s):  
Cancer Therapy ◽  
Water Soluble ◽  
New Class ◽  
Photodynamic Cancer Therapy ◽  
Ph Dependent ◽  
A Charge

A water-soluble, charge-switchable, four-armed polymeric photosensitizer (C4P-PS), in which charge switching is pH dependent, has been designed as a new class of photosensitizer for photodynamic cancer therapy.

scholarly journals Phytocannabinoids in Neurological Diseases: Could They Restore a Physiological GABAergic Transmission?

2020 ◽  
Vol 21 (3) ◽  
pp. 723 ◽  
Author(s):  
Pierangelo Cifelli ◽  
Gabriele Ruffolo ◽  
Eleonora De Felice ◽  
Veronica Alfano ◽  
Erwin Alexander van Vliet ◽  
...  
Keyword(s):  
Neuronal Excitability ◽  
Neurological Diseases ◽  
Chloride Ion ◽  
Gaba Release ◽  
New Class ◽  
Inhibitory Function ◽  
Acid Type ◽  
Wide Range ◽  
The Central Nervous System ◽  
Neurological Conditions

γ-Aminobutyric acid type A receptors (GABAARs) are the main inhibitory mediators in the central nervous system (CNS). GABAARs are pentameric ligand gated ion channels, and the main subunit composition is usually 2α2βγ, with various isotypes assembled within a set of 19 different subunits. The inhibitory function is mediated by chloride ion movement across the GABAARs, activated by synaptic GABA release, reducing neuronal excitability in the adult CNS. Several studies highlighted the importance of GABA-mediated transmission during neuro-development, and its involvement in different neurological and neurodevelopmental diseases, from anxiety to epilepsy. However, while it is well known how different classes of drugs are able to modulate the GABAARs function (benzodiazepines, barbiturates, neurosteroids, alcohol), up to now little is known about GABAARs and cannabinoids interaction in the CNS. Endocannabinoids and phytocannabinoids are lately emerging as a new class of promising drugs for a wide range of neurological conditions, but their safety as medication, and their mechanisms of action are still to be fully elucidated. In this review, we will focus our attention on two of the most promising molecules (Δ9-tetrahydrocannabinol; Δ9-THC and cannabidiol; CBD) of this new class of drugs and their possible mechanism of action on GABAARs.

In Situ microscopy of the anodic etching of silicon

1995 ◽  
Vol 53 ◽  
pp. 232-233
Author(s):  
Frances M. Ross ◽  
Peter C. Searson
Keyword(s):  
Composite Structures ◽  
High Surface ◽  
High Surface Area ◽  
Chemical Properties ◽  
Selective Etching ◽  
Silicon On Insulator ◽  
Second Phase ◽  
Porous Layers ◽  
New Class ◽  
Porous Semiconductors

Porous semiconductors represent a relatively new class of materials formed by the selective etching of a single or polycrystalline substrate. Although porous silicon has received considerable attention due to its novel optical properties1, porous layers can be formed in other semiconductors such as GaAs and GaP. These materials are characterised by very high surface area and by electrical, optical and chemical properties that may differ considerably from bulk. The properties depend on the pore morphology, which can be controlled by adjusting the processing conditions and the dopant concentration. A number of novel structures can be fabricated using selective etching. For example, self-supporting membranes can be made by growing pores through a wafer, films with modulated pore structure can be fabricated by varying the applied potential during growth, composite structures can be prepared by depositing a second phase into the pores and silicon-on-insulator structures can be formed by oxidising a buried porous layer. In all these applications the ability to grow nanostructures controllably is critical.

The microtubule associated protein (MAP) tau forms a new class of triple-stranded left-hand helical fibrous protein polymer

1992 ◽  
Vol 50 (1) ◽  
pp. 540-541
Author(s):  
G. C. Ruben ◽  
K. Iqbal ◽  
I. Grundke-Iqbal ◽  
H. Wisniewski ◽  
T. L. Ciardelli ◽  
...  
Keyword(s):  
Axial Ratio ◽  
Normal Structure ◽  
Paired Helical Filaments ◽  
Left Hand ◽  
New Class ◽  
Protein Polymer ◽  
Fibrous Protein ◽  
Protein Map ◽  
Neurotransmitter Transport ◽  
Alzheimer Neurofibrillary Tangles

In neurons, the microtubule associated protein, tau, is found in the axons. Tau stabilizes the microtubules required for neurotransmitter transport to the axonal terminal. Since tau has been found in both Alzheimer neurofibrillary tangles (NFT) and in paired helical filaments (PHF), the study of tau's normal structure had to preceed TEM studies of NFT and PHF. The structure of tau was first studied by ultracentrifugation. This work suggested that it was a rod shaped molecule with an axial ratio of 20:1. More recently, paraciystals of phosphorylated and nonphosphoiylated tau have been reported. Phosphorylated tau was 90-95 nm in length and 3-6 nm in diameter where as nonphosphorylated tau was 69-75 nm in length. A shorter length of 30 nm was reported for undamaged tau indicating that it is an extremely flexible molecule. Tau was also studied in relation to microtubules, and its length was found to be 56.1±14.1 nm.

Sign in / Sign up

Export Citation Format

Share Document