采用D314树脂从钼精矿焙烧淋洗液中回收钼,探讨了D314树脂加入量、吸附温度、溶液pH值等因素对吸附过程的影响。结果表明,在pH=4时,吸附容量最佳;钼吸附为吸热过程,提高吸附温度,有利于钼的吸附;钼的动态吸附和动态解吸均采用20 m L/h流...采用D314树脂从钼精矿焙烧淋洗液中回收钼,探讨了D314树脂加入量、吸附温度、溶液pH值等因素对吸附过程的影响。结果表明,在pH=4时,吸附容量最佳;钼吸附为吸热过程,提高吸附温度,有利于钼的吸附;钼的动态吸附和动态解吸均采用20 m L/h流速,钼吸附率为96.63%,解吸率为98.81%。红外测试结果表明,10%的氨水溶液可以有效解吸负载树脂上的钼。展开更多
Patients with signs of COVID-19 were tested through diagnostic RT-PCR for SARS-CoV-2 using RNA extracted from the nasopharyngeal/nasal swabs.To determine the variants of SARS-CoV-2 circulating in the state of Nevada,s...Patients with signs of COVID-19 were tested through diagnostic RT-PCR for SARS-CoV-2 using RNA extracted from the nasopharyngeal/nasal swabs.To determine the variants of SARS-CoV-2 circulating in the state of Nevada,specimens from 200 COVID-19 patients were sequenced through our robust sequencing platform,which enabled sequencing of SARS-CoV-2 from specimens with even very low viral loads,without the need of culture-based amplification.High genome coverage allowed the identification of single and multi-nucleotide variants in SARS-CoV-2 in the community and their phylogenetic relationships with other variants present during the same period of the outbreak.We report the occurrence of a novel mutation at 323aa (314aa of orf1b) of nsp12 (RNA-dependent RNA polymerase) changed to phenylalanine(F) from proline (P),in the first reported isolate of SARS-CoV-2,Wuhan-Hu-1.This 323F variant was present at a very high frequency in Northern Nevada.Structural modeling determined this mutation in the interface domain,which is important for the association of accessory proteins required for the polymerase.In conclusion,we report the introduction of specific SARS-CoV-2 variants at very high frequency in distinct geographic locations,which is important for understanding the evolution and circulation of SARS-CoV-2variants of public health importance,while it circulates in humans.展开更多
AIM： To evaluate bacterial cytosine deaminase （bCD） mutant D314A and 5-fluorocytosine （5-FC） for treatment of colon cancer in a mouse model. METHODS： Recombinant lentivirus vectors that contained wild-type bCD g...AIM： To evaluate bacterial cytosine deaminase （bCD） mutant D314A and 5-fluorocytosine （5-FC） for treatment of colon cancer in a mouse model. METHODS： Recombinant lentivirus vectors that contained wild-type bCD gene （bCDwt）, and bCD mutant D314A gene （bCD-D314A） with green fluorescence protein gene were constructed and used to infect hu- man colon carcinoma LoVo cells, to generate stable transfected cells, LoVo/null, LoVo/bCDwt or LoVo/bCD- D314A. These were injected subcutaneously into Balb/c nude mice to establish xenograft models. Two weeks post-LoVo cell inoculation, PBS or 5-FC （500 mg/kg） was administered by intraperitoneal （i.p.） injection once daily for 14 d. On the day after LoVo cell injection, mice were monitored daily for tumor volume and survival. RESULTS： Sequence analyses confirmed the construction of recombinant lentiviral plasmids that contained bCDwt or bCD-D314A. The lentiviral vector had high elficacy for gene delivery, and RT-PCR showed that bCDwt or bCD-D314A gene was transferred to LoVo cells. Among these treatment groups, gene delivery or 5-FC administration alone had no effect on tumor growth. However, bCDwt/5-FC or bCD-D314A/5-FC treatment inhibited tumor growth and prolonged survival of mice significantly （P 〈 0.05）. Importantly, the tumor volume in the bCD-D314A/5-FC-treated group was lower than that in the bCDwt/5-FC group （P 〈 0.05）, and bCD- D314A plus 5-FC significantly prolonged survival of mice in comparison with bCDwt plus 5-FC （P 〈 0.05）. CONCLUSION： The bCD mutant D314A enhanced significantly antitumor activity in human colon cancer xenograft models, which provides a promising approach for human colon carcinoma therapy.展开更多
文摘采用D314树脂从钼精矿焙烧淋洗液中回收钼,探讨了D314树脂加入量、吸附温度、溶液pH值等因素对吸附过程的影响。结果表明,在pH=4时,吸附容量最佳;钼吸附为吸热过程,提高吸附温度,有利于钼的吸附;钼的动态吸附和动态解吸均采用20 m L/h流速,钼吸附率为96.63%,解吸率为98.81%。红外测试结果表明,10%的氨水溶液可以有效解吸负载树脂上的钼。
基金supported by University of Nevada, RenoDepartment of Microbiology & Immunology, UNR School of MedicineNevada IDeA Network of Biomedical Research Excellence (INBRE) from the National Institute of General Medical Sciences (GM 103440 and GM 104944) and from the National Institutes of Health。
文摘Patients with signs of COVID-19 were tested through diagnostic RT-PCR for SARS-CoV-2 using RNA extracted from the nasopharyngeal/nasal swabs.To determine the variants of SARS-CoV-2 circulating in the state of Nevada,specimens from 200 COVID-19 patients were sequenced through our robust sequencing platform,which enabled sequencing of SARS-CoV-2 from specimens with even very low viral loads,without the need of culture-based amplification.High genome coverage allowed the identification of single and multi-nucleotide variants in SARS-CoV-2 in the community and their phylogenetic relationships with other variants present during the same period of the outbreak.We report the occurrence of a novel mutation at 323aa (314aa of orf1b) of nsp12 (RNA-dependent RNA polymerase) changed to phenylalanine(F) from proline (P),in the first reported isolate of SARS-CoV-2,Wuhan-Hu-1.This 323F variant was present at a very high frequency in Northern Nevada.Structural modeling determined this mutation in the interface domain,which is important for the association of accessory proteins required for the polymerase.In conclusion,we report the introduction of specific SARS-CoV-2 variants at very high frequency in distinct geographic locations,which is important for understanding the evolution and circulation of SARS-CoV-2variants of public health importance,while it circulates in humans.
文摘AIM： To evaluate bacterial cytosine deaminase （bCD） mutant D314A and 5-fluorocytosine （5-FC） for treatment of colon cancer in a mouse model. METHODS： Recombinant lentivirus vectors that contained wild-type bCD gene （bCDwt）, and bCD mutant D314A gene （bCD-D314A） with green fluorescence protein gene were constructed and used to infect hu- man colon carcinoma LoVo cells, to generate stable transfected cells, LoVo/null, LoVo/bCDwt or LoVo/bCD- D314A. These were injected subcutaneously into Balb/c nude mice to establish xenograft models. Two weeks post-LoVo cell inoculation, PBS or 5-FC （500 mg/kg） was administered by intraperitoneal （i.p.） injection once daily for 14 d. On the day after LoVo cell injection, mice were monitored daily for tumor volume and survival. RESULTS： Sequence analyses confirmed the construction of recombinant lentiviral plasmids that contained bCDwt or bCD-D314A. The lentiviral vector had high elficacy for gene delivery, and RT-PCR showed that bCDwt or bCD-D314A gene was transferred to LoVo cells. Among these treatment groups, gene delivery or 5-FC administration alone had no effect on tumor growth. However, bCDwt/5-FC or bCD-D314A/5-FC treatment inhibited tumor growth and prolonged survival of mice significantly （P 〈 0.05）. Importantly, the tumor volume in the bCD-D314A/5-FC-treated group was lower than that in the bCDwt/5-FC group （P 〈 0.05）, and bCD- D314A plus 5-FC significantly prolonged survival of mice in comparison with bCDwt plus 5-FC （P 〈 0.05）. CONCLUSION： The bCD mutant D314A enhanced significantly antitumor activity in human colon cancer xenograft models, which provides a promising approach for human colon carcinoma therapy.
