Transparent to gray, odorless powder. Irritating to the skin and eyes on contact. Inhalation will cause irritation in the respiratory tract. [Note: Amorphous silica is the non-crystalline form of SiO2.]
Evaluation: There is inadequate evidence in humans for the carcinogenicity of amorphous silica. There is inadequate evidence in experimental animals for the carcinogenicity of uncalcined diatomaceous earth. There is inadequate evidence in experimental animals for the carcinogenicity of synthetic amorphous silica. Overall evaluation: Amorphous silica is not classifiable as to its carcinogenicity to humans (Group 3).
IARC Monographs:Volume Sup 7: Overall Evaluations of Carcinogenicity: An Updating of IARC Monographs Volumes 1 to 42, 1987; 440 pages; ISBN 92-832-1411-0 (out of print)
来源:International Agency for Research on Cancer (IARC)
毒理性
暴露途径
吸入，皮肤和/或眼睛接触
inhalation, skin and/or eye contact
来源:The National Institute for Occupational Safety and Health (NIOSH)
...Rats /were exposed/ by inhalation to... silica (particle size 0.5 to 5 m) in the form of Belgian glass sand for periods ranging from 0.5 to 40 hr. The initial deposition of silica was highest in the tracheobronchial ciliated air passages; it also was seen throughout the acini, where the extent of deposition decreased as the respiratory airways proceeded distally. The distribution of particles was not uniform between the different acini, and, 2 to 3 months following cessation of exposure, aggregates were formed, primarily in the proximal alveolar ducts but also in the distal portion of the acini.
Inhalation studies with rats... indicate that the long-term clearance of quartz after inhalation is slow and biphasic, whereas amorphous silica dusts are cleared more rapidly. The absolute amount of silica dust eliminated increased with lung burden, but the efficiency of the elimination was either constant or decreased with time. ...The half-life lung clearance of rats exposed via inhalation to an amorphous silica suspension (Ludox ) at concentrations up to 150 mg/cu m was about 50 days.
A study /in (1983)/, showed that the total silica content in the lungs of guinea pigs exposed by inhalation for up to 2 years to a cristobalite sample or to amorphous silica (at dust concentrations of 150 mg/cu m or 100 mg/cu m , respectively) increased linearly over 21 months, without evidence that lung retention rates changed with time. ...The maximum lung content of cristobalite was only 68 mg/lung, whereas that of amorphous silica was 120 mg/lung. The total amount of accumulated silica varied inversely with the degree of pulmonary damage. /It was/ suggested that silica dust producing cell damage may be more efficiently cleared from the lung than are the less toxic amorphous forms. However, this difference also could be due to different rates of deposition for the two dust forms. The cristobalite sample, which was 45% cristobalite and 55% diatomaceous earth, was significantly coarser (and less likely to deposit in the lungs) than the amorphous silica, which contained 100% diatomaceous earth. Also, tissue changes induced by cristobalite could have altered particle deposition.
In a long-term inhalation study with guinea pigs, ...the amount of silica retained as a result of 8-hr/day exposures to amorphous silica (Hi-Sil 233) /was compared/ with that retained during inhalation of quartz dust for a comparable 12-month period. Guinea pigs that inhaled quartz dust at a concentration of 106 mg/cu m retained between 500 and 600 mg of silica, whereas <10 mg of dust was retained in those that inhaled 126 mg/cu m of amorphous silica. After 12 months of exposure, the relative silica content (silica mass/lung mass) decreased in guinea pigs exposed to quartz dust, but continued to increase slowly in the animals exposed to the amorphous silica. This difference was explained by an increasing nonsiliceous materials content (e.g., collagen, minerals) in the lungs of the quartz-exposed animals associated with the progressive deposition of fibrous tissue in the lungs. Six months after cessation of exposure, the silica content of the lungs of Hi-Sil 233-exposed animals was similar to that of untreated controls. This lack of accumulation may be due, in large part, to the higher solubility of amorphous silica compared to quartz... . By comparison, the elimination of silica from the quartz-exposed guinea pigs was negligible, and the silicotic lesions continued to progress during this elimination phase.
Generation, low-temperature stabilization, structure, and reactivity of intermediates with low-coordinated carbon, silicon, and germanium atoms
摘要：
The mechanisms of thermal and photochemical transformations of organic and organometallic compounds which pass through formation of different reactive intermediates were investigated by low-temperature matrix IR spectroscopy. Low-temperature matrix stabilization of the intermediates, the primary products of these reactions, was conducted at 10-15 K. The spectral and structural parameters of the free radicals (CCl3, CCl2Br, CClBr2, CH2CH=CH2, CF2CF=CF2, CH2-C=CH, CH2C=N, CH2Ph, CF2C6F5), halocarbenes and their silicon and germanium analogs, and unstable molecules with double-bond silicon and germanium atoms were obtained as a result.
Circular RNA, along with related compositions and methods are described herein. In some embodiments, the inventive circular RNA comprises post splicing group I in iron fragments, spacers, an IRES, optional duplex forming regions, and more than one expression sequence. In some embodiments, the expression sequences are separated by one or more polynucleotide sequences encoding a cleavage site. In some embodiments, circular RNA of the invention has improved expression, functional stability, immunogenicity, ease of manufacturing, and/or half-life when compared to linear RNA. In some embodiments, inventive methods and constructs result in improved circularization efficiency, splicing efficiency, and/or purity when compared to existing RNA circularization approaches.
Azole derivatives, process for their preparation and their use
申请人：Hoechst Aktiengesellschaft
公开号：US05482957A1
公开（公告）日：1996-01-09
Azole derivatives, process for their preparation, and their use Azole derivatives of the formula (I) ##STR1## in which A, L, O, R.sup.1, X, Y, Z and q have the meanings given, process for their preparation, pharmaceutical preparations and the use of the compounds are described. Azole derivatives of the formula I where the symbols have for example the following meanings: R.sup.1 is (C.sub.2 -C.sub.10)-alkyl, Z is nitrogen, X and Y are independently of one another CR.sup.2, L is --CH.sub.2 --, q is zero or 1, A is a biphenyl radical which is substituted for example by R.sup.15, R.sup.2 is halogen or hydrogen, R.sup.15 is SO.sub.2 --NH--CO--OR.sup.6 and R.sup.6 is phenyl, are highly active antagonists of angiotensin II receptors.
INHIBITORS OF HEMOPOIETIC CELL KINASE (P59-HCK) AND THEIR USE IN THE TREATMENT OF INFLUENZA INFECTION
申请人：Charron Catherine Elisabeth
公开号：US20120244120A1
公开（公告）日：2012-09-27
The present invention relates inter alia to the treatment or prevention of influenza virus infection (including subtypes influenza A virus, influenza B virus, avian strain H5N1, A/H1N1, H3N2 and/or pandemic influenza) using compounds which inhibit the activity of p59-HCK and to a method of screening for a candidate drug substance intended to prevent or treat influenza virus infection in a subject, said method comprising identifying a test substance capable of inhibiting p59-HCK activity.
ANTI-BACTERIAL CALCIUM-DEPENDENT ANTIBIOTIC (CDA) ANALOGS AND METHODS OF TREATING BACTERIAL INFECTIONS
申请人：THE UNIVERSITY OF HONG KONG
公开号：US20210324009A1
公开（公告）日：2021-10-21
Provided herein are calcium-dependent antibiotics (CDAs), as a novel therapeutic target for treating bacterial infections. The present invention also relates to pharmaceutical compositions comprising such compounds, and to methods of use thereof for combating bacteria and treating bacterial infections.
Antibacterial agents, and 4-thio azetidinone intermediates
申请人：Bristol-Myers Company
公开号：US04272437A1
公开（公告）日：1981-06-09
This invention relates to 2-substituted and 2,6-disubstituted penem compounds of the formula ##STR1## wherein Y is hydrogen, halo or certain organic substituents and X represents certain organic substituents. Also included in the invention are pharmaceutically acceptable salts of the above compounds and derivatives of the above compounds in which the carboxyl group at the 3-position is protected as by an easily removable ester protecting group. The compounds of the present invention are potent antibacterial agents or are of use as intermediates in the preparation of such agents.
The present invention provides a novel bridged artificial nucleic acid and an oligomer containing the same as a monomer. The present invention provides specifically a compound represented by general formula (I) (wherein each symbol is the same as defined in the specification) or salts thereof; as well as an oligonucleotide compound represented by general formula (I′) (wherein each symbol is the same as defined in the specification) or salts thereof.
