检索结果-南通市图书馆

Elucidating the Degradation Pathways of Human Insulin in the Solid State

在线全文

学校读者我要写书评

暂无评论

Journal of Analysis and Testing 2024年第3期8卷 288-299页

作者： Andrew Fagan Lorraine M.Bateman Joseph P.O'Shea Abina M.Crean SSPC the SFI Centre for Pharmaceutical Research School of Pharmacy University College Cork School of pharmacy University College Cork Analytical and Biological chemistry Research Facility (ABCRF) University College Cork School of chemistry University College Cork

While there have been significant advances in the development of peptide oral dosage forms in recent years, highlighted by the clinical and commercial success of approved peptides such as Rybelsus?, there remain several barriers in the way of broad range applicability of this approach to peptide delivery. One such barrier includes the poor physical and chemical stability inherent to their structures, which persists in the solid state although degradation typically occurs at different rates and via different pathways in comparison to the solution state. Using insulin as a model peptide, this work sought to contribute to the development of analytical techniques for investigating common insulin degradation pathways. Chemically denatured,deamidated and aggregated samples were prepared and used to benchmark circular dichroism spectroscopy, reverse phase HPLC and size exclusion chromatography methods for the investigation of unfolding, chemical modifications and covalent aggregation of the insulin molecule respectively. Solid state degraded samples were prepared by heating insulin powder at 60 °C and 75% relative humidity for 1, 3, 5 and 7 d, and the degradation profiles of the samples were evaluated and compared with those observed in solution. While no unfolding was observed to occur, significant deamidation and covalent aggregation were detected. Reductive disulfide bond cleavage using dithiothreitol allowed for separation of the insulin A-and B-chains,offering a facile yet novel means of assessing the mechanisms of deamidation and covalent aggregation occurring in the solid state.

关键词： Biopharmaceutical analysis Covalent aggregation Deamidation Disulfide cleavage Insulin Solid state Stability

REMnO3（RE=Pr,Nd,Sm,Eu,Gd） perovskite as efficient catalysts for oxygen reduction reaction

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第11期42卷 2078-2087页

作者： Rakesh Ranjan Mahalik Siba Soren Ipsha Hota A.K.Debnath K.P.Muthe Purnendu Parhi department of chemistry Ravenshaw University Technical Physics Division Bhabha Atomic Research Centre

Rare earth metal based perovskite emerges as important catalytic material for energy production and *** ABO3type materials are now the focus of research in the field of oxygen reduction and evolution ***,in this work we evaluated the oxygen reduction properties of the synthesized one-dimensional REMnO3（RE=Pr,Nd,Sm,Eu and Gd）.The one-dimensional REMnO3prepared by the hydrothermal synthesis route results in pure phase perovskite on *** perovskite was characte rized with X-ray diffraction,Fourier transform-infrared（FT-IR）,field emission-scanning electron microscopy（FE-SEM）,transmission electron microscopy（TEM） and X-ray photoelectron spectroscopy（XPS）.The oxygen reduction reaction activities were investigated with the help of electrochemical workstation that consists of three-electrode system immersed in 0.1 mol/L KOH electrolyte solution saturated with *** Koutechy-Levich plot obtained from rotating ring disk electrode shows all the prepared catalysts follow 4e-processes during oxygen *** effect of "A" site cation variation in REMnO3 on oxygen reduction reaction is ***3showed better onset potential for oxygen reduction reaction among the prepared rare earth ***3having high RE:Mn ratio（A-site rich co mpositions） promotes oxygen reduction reaction（ORR） *** the perovs kites showed good oxygen reduction property with high stability and methanol tolerance.

关键词： Electrocatalytic activity Oxygen reduction reaction (ORR) Perovskite Rare earths REMnO3 SmMnO3

Engineering of efficient visible light photocatalysts:Ti_(1-x+y)Cu_(x)La_(y)O_(2)(x=0.03;y=0,0.005,0.01) compositions

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第3期42卷 497-505,I0003页

作者： S.M.Yakout A.M.Youssef Inorganic chemistry department National Research Centre(NRC)El Buhouth StDokkiCairo12622Egypt

In dye-photocatalysis, widening the wavelengths absorption range of catalysts as well as aborting the recombination of the photoexcited charge carriers(electrons-holes pairs) are of paramount *** the current study, we report the photocatalytic characteristics of four compositions composed of TiO_(2),Ti_(0.97)Cu_(0.03)O_(2), Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders for two harmful dyes(Congo red and methylene blue). The X-ray diffraction technique verified the configuration of mixed anatase and rutile phases in pure TiO_(2)and Ti_(0.97)Cu_(0.03)O_(2)powders while Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders possess anatase phase only. The changes of the band gap structure and dimensions of the unit cell volume of TiO_(2)confirm the substitution of Ti^(4+)sites by Cu^(2+)and La^(3+)ions. Remarkable widening of wavelengths absorption with formation of long absorption tails were found in TiO_(2)(3.13 e V) through insertion of La^(3+)plus Cu^(2+)ions. Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)samples exhibit a visible light band gap of 2.3 and 2.7 e V, respectively. Based on SEM images, incorporation of Cu^(2+)and La^(3+)ions influences the surface morphology of TiO_(2). The resulting Ti_(0.97)Cu_(0.03)O_(2), Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders present enhanced photocatalytic activity towards Congo red dye degradation compared to pure one under natural solar spectrum. The best Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)catalyst exhibits superior photocatalytic activity of 96% for 10 ppm CR dye in 20 min as well as above average photocatalytic efficiency of 63% for 30 ppm CR dye in 120 min. As well, it showed acceptable photodegradation activity of 52% for 30 ppm MB solution in 140 min of sunlight irradiation. The heightened photodegradation efficiency of Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)catalyst can be clarified in terms of higher ch

关键词： Semiconductor TiO_(2) Rare earths Congo red Methylene blue Solar spectrum Photodegradation

Phosphorylation-driven aggregative proteins in neurodegenerative diseases:implications and therapeutics

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2024年第5期19卷 966-968页

作者： Alba Espargaró Raimon Sabate department of pharmacy and Pharmaceutical Technology and Physical-chemistry School of PharmacyUniversity of BarcelonaBarcelonaSpain Institute of Nanoscience and Nanotechnology(IN2UB) University of BarcelonaBarcelonaSpain

Protein aggregation is related to a large number of neurodegenerative *** in some cases,aggregation is induced by hyperphosphorylation of a given *** is the case of tau,TAR DNA-binding protein 43(TDP-43),amyloid-beta peptides(Aβ)and alpha-synuclein(α-syn),which play a key pathogenic role in Alzheimer’s disease(AD),Parkinson’s disease(PD)and amyotrophic lateral sclerosis,among others(Tenreiro et al.,2014;Chiti and Dobson,2017).In this perspective,we will discuss both the relationship between phosphorylation and amyloid aggregation as well as current and future therapeutic strategies aimed at inhibiting specific kinases involved in the phosphorylation step or inhibiting subsequent protein aggregation.

关键词： tau Aβ Alzheimer

Stereospecific Assembly of Trisubstituted Alkenes via Photoinduced Nitrogen-Centered Radical-Triggered C—C Bond Cleavage/Functionalization of Oxime Esters

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of chemistry 2024年第12期42卷 1399-1406页

作者： Yu Bao Zhi-Jie Song Jin-Long Dai Shenghu Yan Yue Zhang Jia-Yin Wang Guigen Li School of pharmacy Changzhou UniversityChangzhouJiangsu 213164China department of chemistry and Biochemistry Texas Tech University79409USA

Comprehensive Summary A general and convenient photoredox-catalyzed acylation and alkylcyanation of MBH acetates has been established,enabling the assembly of the C(sp2)–C(sp3)bond by a nitrogen-centered radical strategy for the synthesis of trisubstituted alkenes in moderate to excellent chemical yields(48 examples in total).The reaction of MBH acetates with acyl(indanone)oxime esters afforded trisubstituted alkenes containing 1,4-dicarbonyl ***,the use of Eosin Y as a photocatalyst in the catalytic system resulted in the formation of distal cyano group-anchored trisubstituted alkenes via deconstructive functionalization of cycloketone oxime ***,these resulting 1,4-dicarbonyl compounds could be applied to late-stage transformations,providing important methods for the synthesis of dihydropyridazin-3(2H)-one.

关键词： Photocatalysis Radical reactions MBH acetates Oxime esters Stereoselectivity Acylation Alkylation Green chemistry

Molecular solid solution of lanthanide-titanium-oxo clusters with enhanced photocatalytic hydrogen evolution

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China chemistry 2024年第2期67卷 529-535页

作者： Rong Chen Chao-Long Chen Hui Zhang Zi-Han Wang Fu-Li Sun Ming-Hao Du Gui-Lin Zhuang Cheng Wang La-Sheng Long Lan-Sun Zheng Xiang-Jian Kong Collaborative Innovation centre of chemistry for Energy Materials State Key Laboratory of Physical chemistry of Solid Surfaces and department of chemistry College of Chemistry and Chemical EngineeringXiamen UniversityXiamen361005China College of Chemical Engineering Zhejiang University of TechnologyHangzhou310032China

Molecular solid solutions of metal clusters containing different metal centers with well-defined structures can accurately regulate the HOMO-LUMO gap,but are rarely ***,a series of colorless lanthanide-titanium-oxo clusters Ln_(2)Ti_4(μ_(2)-O)_(2)(μ_(3)-O)_4(Piv)_(10)(THF)_(2)(Ln_(2)Ti_4,Ln = Eu,Gd,Tb,and Ce,HPiv = pivalic acid) were synthesized by the reaction of pivalic acid with Ln(Ac)_(3) and titanium *** light yellow crystal of cluster solid solutions Eu_(2)Ti_(4-x)Cd_(x),containing a mixture of Eu_(2)Ti_4 and Eu_(2)Ti_(3)Cd,was obtained by in situ doping Cd^(2+) and S^(2–).Eu_(2)Ti_(3.92)Cd_(0.08) displays efficient photocatalytic hydrogen evolution activity without a co-catalyst,which is up to 2.6 times that of Eu_(2)Ti_*** time-resolved transient absorption spectroscopy and spin-polarized density functional calculations showed that the enhanced photocatalytic performance of Eu_(2)Ti_(4-x)Cd_(x) can be attributed to the narrower HOMO-LUMO gap and lower LUMO position than that of Eu_(2)Ti_*** studyprovides an in situ doping method to realize the simple preparation of cluster solid solution.

关键词： molecular solid solution lanthanide-titanium-oxo clusters photocatalytic hydrogen evolution

A new tetracyclic triterpenoid from endophytic fungus Fusarium sporotrichioides

在线全文

学校读者我要写书评

暂无评论

Chinese Herbal Medicines 2024年第2期16卷 231-234页

作者： Yajing Wang Chunyue Liu Yihui Yang Chang Li Yuehu Pei department of Medicinal chemistry and Natural Medicine chemistry College of PharmacyHarbin Medical UniversityHarbin 150081China

Objective: To isolate bioactive compounds from the endophytic fungus Fusarium sporotrichioides isolated from Rauwolfia yunnanensis, and investigate their pharmacological ***: The chemical constituents were isolated and purified by combining with ODS column chromatography, silica gel column chromatography and by performing semipreparative HPLC. Their structures were established on the basis of 1D NMR(1H-NMR and13C-NMR) and 2D NMR(1H–1H COSY,HSQC, HMBC and NOESY), as well as HRESIMS and comparison with literature data. In addition, the absolute configuration of compound 1 was determined by calculated ECD ***: One previously undescribed tetracyclic triterpenoid derivative, named as integracide L(1), 12aacetoxy-4,4-dimethyl-24-methylene-5a-cholesta-8,14-diene-2a,3β,11β-triol(2), 12a-acetoxy-4,4-dime thyl-24-methylene-5a-cholesta-8-momoene-2a,3β,11β-triol(3), 12a-acetoxy-4,4-dimethyl-24-methy lene-5a-cholesta-8,14-diene-3β,11β-triol(4), and 12a-acetoxy-4,4-dimethyl-24-methylene-5acholesta-8-momoene-3β,11β-triol(5) were isolated from F. sporotrichioide. Moreover, compound 1 was rare tetracyclic triterpenoid with single methyl replacement at C-4 ***: Compound 1 was a new tetracyclic triterpenoid isolated from the endophytic fungus ***. In addition, compound 2 could inhibit the growth of three different human cancer cells significantly. Compounds 3 and 5 were found to possess better cytotoxic activities on Hep G-2 cells than the other compounds, with IC50values of(2.8 ± 0.1) and(6.3 ± 0.3) μmol/L respectively.

关键词： antitumor Fusarium sporotrichioides integracide L tetracyclic triterpenoid 12a-acetoxy-4,4-dimethyl-24-methylene5a-cholesta-814-diene-2a,3b,11b-triol 12a-acetoxy-4,4-dimethyl-24-methylene5a-cholesta-8-momoene-2a,3b,11b-triol 12a-acetoxy-4,4-dimethyl-24-methylene5a-cholesta-8-momoene-3b,11b-triol

Progress in experimental models to investigate the in vivo and in vitro antidiabetic activity of drugs

在线全文

学校读者我要写书评

暂无评论

Animal Models and Experimental Medicine 2024年第3期7卷 297-309页

作者： Yasodha Krishna Janapati Sunil Junapudi School of pharmacy&Health Sciences United States International University-AFRICA(USIU-A)NairobiKenya department of Pharmaceutical chemistry Geethanjali College of PharmacyKeesaraIndia

Diabetes mellitus is one of the world's most prevalent and complex metabolic disorders,and it is a rapidly growing global public health *** is characterized by hyperglycemia,a condition involving a high blood glucose level brought on by deficiencies in insulin secretion,decreased activity of insulin,or *** effects of diabetes include cardiovascular problems,retinopathy,neuropathy,nephropathy,and vascular alterations in both macro-and micro-blood *** vivo and in vitro models have always been important for investigating and characterizing disease pathogenesis,identifying targets,and reviewing novel treatment options and *** understanding these models is crucial for the researchers so this review summarizes the different experimental in vivo and in vitro model options used to study diabetes and its *** most popular in vivo studies involves the small animal models,such as rodent models,chemically induced diabetogens like streptozotocin and alloxan,and the possibility of deleting or overexpressing a specific gene by knockout and transgenic technologies on these *** models include virally induced models,diet/nutrition induced diabetic animals,surgically induced models or pancreatectomy models,and non-obese *** animals or non-rodent models like porcine(pig),canine(dog),nonhuman primate,and Zebrafish models are also *** in vitro models discussed are murine and human beta-cell lines and pancreatic islets,human stem cells,and organoid *** other enzymatic in vitro tests to assess diabetes include assay of amylase inhibition and inhibition ofα-glucosidase activity.

关键词： animal models diabetes mellitus typeⅠ diabetes mellitus typeⅡ in vitro and in vivo models

New insight into targeting the DNA damage response in the treatment of glioblastoma

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Natural Medicines 2024年第10期22卷 869-886页

作者： ZHEN Tengfei SUN Tianyu XIONG Baichen LIU Hui WANG Lei CHEN Yao SUN Haopeng School of pharmacy China Pharmaceutical University department of chemistry Tsinghua University School of pharmacy Nanjing University of Chinese Medicine

Glioblastoma(GBM) is the most common invasive malignant tumor in human brain tumors, representing the most severe grade of gliomas. Despite existing therapeutic approaches, patient prognosis remains dismal, necessitating the exploration of novel strategies to enhance treatment efficacy and extend survival. Due to the restrictive nature of the blood-brain barrier(BBB), smallmolecule inhibitors are prioritized in the treatment of central nervous system tumors. Among these, DNA damage response(DDR) inhibitors have garnered significant attention due to their potent therapeutic potential across various malignancies. This review provides a detailed analysis of DDR pathways as therapeutic targets in GBM, summarizes recent advancements, therapeutic strategies, and ongoing clinical trials, and offers perspectives on future directions in this rapidly evolving field. The goal is to present a comprehensive outlook on the potential of DDR inhibitors in improving GBM management and outcomes.

关键词： DNA damage response Glioblastoma Small molecule inhibitors