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1.
Molecules ; 28(22)2023 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-38005263

RESUMO

Photocatalytic technology for inactivating bacteria in water has received much attention. In this study, we reported a dark-light dual-mode sterilized g-C3N4/chitosan/poly (vinyl alcohol) hydrogel (g-CP) prepared through freeze-thaw cycling and an in situ electron-beam radiation method. The structures and morphologies of g-CP were confirmed using Fourier infrared spectroscopy (FTIR), X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), solid ultraviolet diffuse reflectance spectroscopy (UV-vis DRS), and Brunauer-Emmett-Teller (BET). Photocatalytic degradation experiments demonstrated that 1 wt% g-CP degraded rhodamine B (RhB) up to 65.92% in 60 min. At the same time, g-CP had good antimicrobial abilities for Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) within 4 h. The shapes of g-CP were adjustable (such as bar, cylinder, and cube) and had good mechanical properties and biocompatibility. The tensile and compressive modulus of 2 wt% g-CP were 0.093 MPa and 1.61 MPa, respectively. The Cell Counting Kit-8 (CCK-8) test and Hoechst33342/PI double staining were used to prove that g-CP had good biocompatibility. It is expected to be applied to environmental sewage treatment and wound dressing in the future.


Assuntos
Escherichia coli , Staphylococcus aureus , Nanogéis , Elétrons , Microscopia Eletrônica de Varredura
2.
RSC Adv ; 11(11): 6173-6181, 2021 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-35423147

RESUMO

A new spherical cellulose-based adsorbent and high phosphate removal rate microcrystalline cellulose-g-acrylamide/ethylenediamine/phthalic anhydride (MCC-g-AM/EDA/PA) loaded Fe(iii) adsorbent was prepared by a pre-radiation grafting and chemical modification method. Fe(iii) was successfully introduced into the modified grafted chains of the MCC-g-AM/EDA/PA resin, and characterized by FTIR, TG, XRD, SEM and XPS. The optimized conditions for the grafting reaction of acrylamide (AM) onto MCC were 20% AM emulsion at an absorbed dose of 30 kGy, and a grafting rate as high as 247%. In addition, the adsorption performance of the adsorbent was tested by static adsorption experiments with phosphate. The adsorbent resin showed excellent adsorption performance under alkaline conditions, contributions to the synergetic effect of precipitation, and inner-sphere surface complex reactions. The adsorption efficiency can reach 89.7% at low concentration. In summary, the neotype spherical cellulose-based adsorbent has the advantages of being separation-free in bulk materials, avoiding secondary pollution, and being easy to recycle, and it could be employed as an environmentally friendly adsorbent for phosphate removal in eutrophic water.

3.
J Org Chem ; 85(2): 493-500, 2020 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-31845809

RESUMO

A highly efficient synthetic method for the preparation of 2-aminobenzothiazoles starting from arylthioureas has been reported. By using a nickel catalyst, arylthioureas undergo intramolecular oxidative C-H bond functionalization, giving the desired 2-aminobenzothiazoles in good to excellent yields. This protocol features an inexpensive catalyst, low catalyst loading, mild reaction conditions, a short reaction time, and good to excellent yields, and it can be scaled up easily to a gram scale with almost no yields decreasing.

4.
Front Immunol ; 10: 457, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30930899

RESUMO

The Lin28b+Let7- axis in fetal/neonatal development plays a role in promoting CD5+ B1a cell generation as a B-1 B cell developmental outcome. Here we identify the Let7 target, Arid3a, as a crucial molecular effector of the B-1 cell developmental program. Arid3a expression is increased at pro-B cell stage and markedly increased at pre-B and immature B cell stages in the fetal/neonatal liver B-1 development relative to that in the Lin28b-Let7+ adult bone marrow (BM) B-2 cell development. Analysis of B-lineage restricted Lin28b transgenic (Tg) mice, Arid3a knockout and Arid3a Tg mice, confirmed that increased Arid3a allows B cell generation without requiring surrogate light chain (SLC) associated pre-BCR stage, and prevents MHC class II cell expression at the pre-B and newly generated immature B cell stages, distinct from pre-BCR dependent B development with MHC class II in adult BM. Moreover, Arid3a plays a crucial role in supporting B1a cell generation. The increased Arid3a leads higher Myc and Bhlhe41, and lower Siglec-G and CD72 at the pre-B and immature B cell stages than normal adult BM, to allow BCR signaling induced B1a cell generation. Arid3a-deficiency selectively blocks the development of B1a cells, while having no detectable effect on CD5- B1b, MZ B, and FO B cell generation resembling B-2 development outcome. Conversely, enforced expression of Arid3a by transgene is sufficient to promote the development of B1a cells from adult BM. Under the environment change between birth to adult, altered BCR repertoire in increased B1a cells occurred generated from adult BM. However, crossed with B1a-restricted VH/D/J IgH knock-in mice allowed to confirm that SLC-unassociated B1a cell increase and CLL/lymphoma generation can occur in aged from Arid3a increased adult BM. These results confirmed that in fetal/neonatal normal mice, increased Arid3a at the pre-B cell and immature B cell stages is crucial for generating B1a cells together with the environment for self-ligand reactive BCR selection, B1a cell maintenance, and potential for development of CLL/Lymphoma in aged mice.


Assuntos
Subpopulações de Linfócitos B/imunologia , Proteínas de Ligação a DNA/imunologia , Células Precursoras de Linfócitos B/metabolismo , Fatores de Transcrição/imunologia , Envelhecimento/genética , Envelhecimento/imunologia , Animais , Proteínas de Ligação a DNA/genética , Regulação Leucêmica da Expressão Gênica , Antígenos de Histocompatibilidade Classe II/genética , Antígenos de Histocompatibilidade Classe II/imunologia , Leucemia Linfocítica Crônica de Células B/genética , Leucemia Linfocítica Crônica de Células B/imunologia , Camundongos , Camundongos Knockout , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/imunologia , Receptores de Antígenos de Linfócitos B/genética , Receptores de Antígenos de Linfócitos B/imunologia , Fatores de Transcrição/genética
5.
Front Immunol ; 10: 645, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31001264

RESUMO

Despite significant progress, China faces the challenge of re-emerging schistosomiasis transmission in currently controlled areas due, in part, to the presence of a range of animal reservoirs, notably water buffalo and cattle, which can harbor Schistosoma japonicum infections. Environmental, ecological and social-demographic changes in China, shown to affect the distribution of oncomelanid snails, can also impact future schistosomiasis transmission. In light of their importance in the S. japonicum, lifecycle, vaccination has been proposed as a means to reduce the excretion of egg from cattle and buffalo, thereby interrupting transmission from these reservoir hosts to snails. A DNA-based vaccine (SjCTPI) our team developed showed encouraging efficacy against S. japonicum in Chinese water buffaloes. Here we report the results of a double-blind cluster randomized trial aimed at determining the impact of a combination of the SjCTPI bovine vaccine (given as a prime-boost regimen), human mass chemotherapy and snail control on the transmission of S. japonicum in 12 selected administrative villages around the Dongting Lake in Hunan province. The trial confirmed human praziquantel treatment is an effective intervention at the population level. Further, mollusciciding had an indirect ~50% efficacy in reducing human infection rates. Serology showed that the SjCTPI vaccine produced an effective antibody response in vaccinated bovines, resulting in a negative correlation with bovine egg counts observed at all post-vaccination time points. Despite these encouraging outcomes, the effect of the vaccine in preventing human infection was inconclusive. This was likely due to activities undertaken by the China National Schistosomiasis Control Program, notably the treatment, sacrifice or removal of bovines from trial villages, over which we had no control; as a result, the trial design was compromised, reducing power and contaminating outcome measures. This highlights the difficulties in undertaking field trials of this nature and magnitude, particularly over a long period, and emphasizes the importance of mathematical modeling in predicting the potential impact of control intervention measures. A transmission blocking vaccine targeting bovines for the prevention of S. japonicum with the required protective efficacy would be invaluable in tandem with other preventive intervention measures if the goal of eliminating schistosomiasis from China is to become a reality.


Assuntos
Anti-Helmínticos/uso terapêutico , Doenças dos Bovinos/prevenção & controle , Praziquantel/uso terapêutico , Esquistossomose Japônica/prevenção & controle , Vacinação/veterinária , Vacinas/uso terapêutico , Adolescente , Adulto , Idoso , Animais , Búfalos , Bovinos , Criança , Pré-Escolar , China , Método Duplo-Cego , Humanos , Pessoa de Meia-Idade , Esquistossomose Japônica/transmissão , Esquistossomose Japônica/veterinária , Caramujos , Adulto Jovem
6.
J Inherit Metab Dis ; 40(1): 113-120, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27444757

RESUMO

Cystathionine ß-synthase (CBS) deficiency is a recessive inborn error of metabolism in which patients have extremely elevated plasma total homocysteine and have clinical manifestations in the vascular, visual, skeletal, and nervous systems. Homocysteine is an intermediary metabolite produced from the hydrolysis of S-adenosylhomocysteine (SAH), which is a by-product of methylation reactions involving the methyl-donor S-adenosylmethionine (SAM). Here, we have measured SAM, SAH, DNA and histone methylation status in an inducible mouse model of CBS deficiency to test the hypothesis that homocysteine-related phenotypes are caused by inhibition of methylation due to elevated SAH and reduced SAM/SAH ratio. We found that mice lacking CBS have elevated cellular SAH and reduced SAM/SAH ratios in both liver and kidney, but this was not associated with alterations in the level of 5-methylcytosine or various histone modifications. Using methylated DNA immunoprecipitation in combination with microarray, we found that of the 241 most differentially methylated promoter probes, 89 % were actually hypermethylated in CBS deficient mice. In addition, we did not find that changes in DNA methylation correlated well with changes in RNA expression in the livers of induced and uninduced CBS mice. Our data indicates that reduction in the SAM/SAH ratio, due to loss of CBS activity, does not result in overall hypomethylation of either DNA or histones.


Assuntos
Cistationina beta-Sintase/genética , Metilação de DNA/genética , Epigênese Genética/genética , Homocistinúria/genética , Animais , Cistationina beta-Sintase/metabolismo , DNA/genética , Modelos Animais de Doenças , Epigenômica/métodos , Homocisteína/genética , Homocisteína/metabolismo , Homocistinúria/metabolismo , Rim/metabolismo , Fígado/metabolismo , Camundongos , S-Adenosil-Homocisteína/metabolismo , S-Adenosilmetionina/metabolismo
7.
Dalton Trans ; 45(25): 10308-18, 2016 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-27241779

RESUMO

Novel Zr(iv) and Hf(iv) complexes bearing two constrained bulky ß-enaminoketonato ligands {[ArN[double bond, length as m-dash]CH-C8H3(CH2)n(R)O]2MBn2, M = Zr or Hf; n = 1, 2 or 3; R = H or C6H5; Ar = C6H5 or C6F5} were synthesized and clearly characterized. X-ray crystal structure analysis reveals that these complexes adopt a distorted octahedral geometry. Compared with non-constrained analogues, the Zr(iv) complexes with a cyclic skeleton exhibited high catalytic activities (up to 16.4 kgPE mmolZr(-1) h(-1)) toward ethylene polymerization at ambient pressure and elevated temperatures. Moreover, the catalytic properties of these complexes could be governed exquisitely by appropriate variation of the N-aryl substituents and the size of the benzocyclane. The Zr(iv) complexes bearing a non-fluorinated N-aryl group yielded oligomers, while the fluorinated analogues bearing a five-membered or six-membered cyclane group produced high molecular weight polyethylenes (33.4-306 kg mol(-1)) under similar conditions on account of the suppression effects on ß-H elimination. The Zr(iv) complexes are more active toward ethylene polymerization than the Hf(iv) analogues, and the resulting polymers exhibited higher molecular weight and narrower molecular weight distribution.

8.
PLoS One ; 10(7): e0131908, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26161877

RESUMO

Genetic screens are a powerful tool to discover genes that are important in immune cell development and function. The evolutionarily conserved development of lymphoid cells paired with the genetic tractability of zebrafish make this a powerful model system for this purpose. We used a Tol2-based gene-breaking transposon to induce mutations in the zebrafish (Danio rerio, AB strain) genome, which served the dual purpose of fluorescently tagging cells and tissues that express the disrupted gene and provided a means of identifying the disrupted gene. We identified 12 lines in which hematopoietic tissues expressed green fluorescent protein (GFP) during embryonic development, as detected by microscopy. Subsequent analysis of young adult fish, using a novel approach in which single cell suspensions of whole fish were analyzed by flow cytometry, revealed that 8 of these lines also exhibited GFP expression in young adult cells. An additional 15 lines that did not have embryonic GFP+ hematopoietic tissue by microscopy, nevertheless exhibited GFP+ cells in young adults. RT-PCR analysis of purified GFP+ populations for expression of T and B cell-specific markers identified 18 lines in which T and/or B cells were fluorescently tagged at 6 weeks of age. As transposon insertion is expected to cause gene disruption, these lines can be used to assess the requirement for the disrupted genes in immune cell development. Focusing on the lines with embryonic GFP+ hematopoietic tissue, we identified three lines in which homozygous mutants exhibited impaired T cell development at 6 days of age. In two of the lines we identified the disrupted genes, agtpbp1 and eps15L1. Morpholino-mediated knockdown of these genes mimicked the T cell defects in the corresponding mutant embryos, demonstrating the previously unrecognized, essential roles of agtpbp1 and eps15L1 in T cell development.


Assuntos
Carboxipeptidases/genética , Linfócitos T/fisiologia , Proteínas de Peixe-Zebra/genética , Animais , Carboxipeptidases/metabolismo , Diferenciação Celular , Expressão Gênica , Técnicas de Silenciamento de Genes , Hematopoese , Mutagênese , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
9.
Ann N Y Acad Sci ; 1362: 8-15, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25931205

RESUMO

Fluorescence-activated cell sorting (FACS)-purified pro-B cells from fetal liver and adult bone marrow generate B cells with distinct phenotypes: fetal cells generate few IgD(high) B cells and half express CD5, whereas adult cells generate mostly IgD(high) cells and few express CD5. These results led us to propose a model of a developmental switch in B lymphopoiesis, similar to the well-known switch in fetal to adult erythropoiesis. More recent global analysis of mRNA and microRNA expression comparing these two types of pro-B cells revealed differential expression of Lin28b and microRNAs from the Let-7 family, indicating that this regulatory axis plays a role in the switch. Further analysis has provided data supporting this model, implicating Arid3a as a key transcription factor in mediating fetal-type B cell development. Function of this regulatory axis in human B lineage precursors may also explain the predominance of CD5(+) B cells in cord blood. We suggest that Lin28b-promoted B cell development generates many cells expressing CD5 as a consequence of positively selected self-reactivity. While such cells serve a useful role in clearance of senescent cells and in certain immune responses, they also carry the risk of progression to leukemia/lymphoma later in life.


Assuntos
Subpopulações de Linfócitos B/fisiologia , Feto/citologia , Feto/fisiologia , Linfopoese/fisiologia , Adulto , Linfócitos B/fisiologia , Humanos
10.
Dalton Trans ; 44(16): 7382-94, 2015 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-25798952

RESUMO

Phosphino-phenolate neutral nickel catalysts 1-3/B(C6F5)3, without the help of any organoaluminum compound, were found to be efficient catalytic systems for norbornene polymerization and its copolymerization with norbornene derivatives. The amount of B(C6F5)3 required for achieving a high efficiency (3 equiv.) was markedly lower compared to previous reports, and high molecular weight polymers were obtained (>10(6) g mol(-1)). Efficient incorporation of polar monomers NBC, NBA, and NBM was also achieved in a controllable fashion, yielding high molecular weight copolymers. Catalysts 1-3 were highly active for ethylene polymerization as single component catalysts, with an activity of up to 10(7) g molNi(-1) h(-1), and catalyst 3 was more readily initiated at lower temperature. Catalysts 1-3 were also efficient in incorporating norbornene (up to 30%) into the polyethylene backbone. Bisligated phosphino-phenolate nickel complex 4 and salicylaldimine complex 5 were also studied for comparison, which further verified the unique performance of catalysts 1-3. Preliminary NMR analyses were conducted to explore the norbornene polymerization mechanism.

11.
J Exp Med ; 212(4): 569-80, 2015 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-25753579

RESUMO

Mouse B cell precursors from fetal liver and adult bone marrow (BM) generate distinctive B cell progeny when transplanted into immunodeficient recipients, supporting a two-pathway model for B lymphopoiesis, fetal "B-1" and adult "B-2." Recently, Lin28b was shown to be important for the switch between fetal and adult pathways; however, neither the mechanism of Lin28b action nor the importance of B cell antigen receptor (BCR) signaling in this process was addressed. Here, we report key advances in our understanding of the regulation of B-1/B-2 development. First, modulation of Let-7 in fetal pro-B cells is sufficient to alter fetal B-1 development to produce B cells resembling the progeny of adult B-2 development. Second, intact BCR signaling is required for the generation of B1a B cells from Lin28b-transduced BM progenitors, supporting a requirement for ligand-dependent selection, as is the case for normal B1a B cells. Third, the VH repertoire of Lin28b-induced BM B1a B cells differs from that of normal B1a, suggesting persisting differences from fetal progenitors. Finally, we identify the Arid3a transcription factor as a key target of Let-7, whose ectopic expression is sufficient to induce B-1 development in adult pro-B cells and whose silencing by knockdown blocks B-1 development in fetal pro-B cells.


Assuntos
Subpopulações de Linfócitos B/imunologia , Proteínas de Ligação a DNA/imunologia , Feto/imunologia , Linfopoese/imunologia , Células Precursoras de Linfócitos B/imunologia , Fatores de Transcrição/imunologia , Animais , Subpopulações de Linfócitos B/citologia , Proteínas de Ligação a DNA/genética , Feminino , Feto/citologia , Regulação da Expressão Gênica/genética , Regulação da Expressão Gênica/imunologia , Linfopoese/genética , Camundongos , Camundongos Endogâmicos BALB C , Camundongos SCID , MicroRNAs/genética , MicroRNAs/imunologia , Células Precursoras de Linfócitos B/citologia , Proteínas de Ligação a RNA , Fatores de Transcrição/genética , Transdução Genética
12.
Dalton Trans ; 44(27): 12273-81, 2015 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-25716981

RESUMO

Aryloxo-modified vanadium(V) dichloride complexes containing a dichloro- or difluoro-phenylimido ligand of the type, V(N-2,6-X2C6H3)Cl2(O-2,6-R2C6H3) [X = Cl (1), F (2); R = Me (a), F (b)], showed remarkable catalytic activity in ethylene polymerisation and the copolymerisation with norbornene (NBE) in the presence of Et2AlCl; the activities were higher than that of V(N-2,6-Me2C6H3)Cl2(O-2,6-Me2C6H3) reported previously. Complex 1a is a suitable catalyst precursor in terms of not only the activity, but also synthesis of high molecular weight copolymers with both unimodal molecular weight distributions and uniform compositions.

13.
Dalton Trans ; 43(34): 12926-34, 2014 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-25026453

RESUMO

A series of oxovanadium(V) complexes containing amine pyridine(s) phenolate ligands [ONN] (2a-f) have been synthesized in high yields (68-83%) by reacting VO(O(n)Pr)3 with 1.0 equiv. of the ligands in CH2Cl2. These complexes were characterized by (1)H, (13)C and (51)V NMR spectroscopy and elemental analysis. X-ray structural analysis for 2a, 2c and 2d revealed that these complexes adopt a six-coordinate distorted octahedral geometry around the vanadium center in the solid state. Upon treatment with Et2AlCl and CCl3COOEt, these complexes displayed high catalytic activities for ethylene polymerization even at elevated reaction temperatures, depending on ligand structures. The resulting polymers possessed high molecular weight and unimodal molecular weight distributions, indicative of the formation of a single catalytically active species during the polymerization catalysis. Excitingly, these vanadium(V) complexes could efficiently promote ethylene/norbornene copolymerization. The observed catalytic activity for the copolymerization was higher than that for ethylene homopolymerization. Moreover, the molecular weights of the resulting copolymers increased upon increasing the norbornene feed. These results indicated that introducing a suitable amount of norbornene into the system not only could accelerate the polymerization rate but also could restrain chain transfer reactions to some extent.

14.
Int J Parasitol ; 44(9): 659-68, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24929133

RESUMO

Despite major successes in its control over the past 50years, schistosomiasis japonica continues to be a public health problem in the People's Republic of China (P.R. China). Historically, the major endemic foci occur in the lakes and marshlands along the Yangtze River, areas where transmission interruption has proven difficult. The current endemic situation may alter due to the closure of the Three Gorges Dam. Considerable environmental and ecological changes are anticipated that may result in new habitats for the oncomelanid intermediate snail host of Schistosoma japonicum (Sj), thereby increasing the risk of transmission. The current national control program for P.R. China involves a multi-component integrated strategy but, despite targeting multiple transmission pathways, certain challenges remain. As the Chinese government pushes towards elimination, there is a requirement for additional tools, such as vaccination, for long-term prevention. Whereas the zoonotic nature of schistosomiasis japonica adds to the complexity of control, it provides a unique opportunity to develop a transmission blocking vaccine targeting bovines to assist in the prevention of human infection and disease. Mathematical modelling has shown that control options targeting the various transmission pathways of schistosomiasis japonica and incorporating bovine vaccination, mass human chemotherapy and mollusciciding could lead to its elimination from P.R. China. Here we present the study design and baseline results of a four-year cluster randomised intervention trial we are undertaking around the schistosomiasis-endemic Dongting Lake in Hunan Province aimed at determining the impact on schistosome transmission of the multi-component integrated control strategy, including bovine vaccination using a heterologous "prime-boost" delivery platform based on the previously tested SjCTPI vaccine.


Assuntos
Doenças dos Bovinos/parasitologia , Niclosamida/farmacologia , Praziquantel/uso terapêutico , Esquistossomose Japônica/prevenção & controle , Esquistossomose Japônica/veterinária , Adolescente , Adulto , Animais , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/prevenção & controle , Criança , Pré-Escolar , China/epidemiologia , Esquema de Medicação , Feminino , Humanos , Lactente , Masculino , Moluscocidas/farmacologia , Praziquantel/administração & dosagem , Esquistossomose Japônica/epidemiologia , Esquistossomicidas/administração & dosagem , Esquistossomicidas/uso terapêutico , Fatores de Tempo , Vacinas/imunologia , Adulto Jovem
15.
Int J Parasitol ; 44(3-4): 167-71, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24440417

RESUMO

Schistosomiasis japonica, caused by Schistosoma japonicum, is an important zoonotic disease in China, the Philippines and small pockets of Indonesia. In addition to infecting people, S. japonicum can infect over 40 species of wild and domestic animals which have varying impacts on human infection. It is now generally accepted that bovines, particularly water buffaloes, are the major reservoir for human infection in China as they are naturally infected with schistosomes and deposit more eggs into the environment than humans or any other animal host. This complicates control efforts and the economic burden associated with schistosomiasis morbidity and mortality has taken its toll on both human and livestock populations. Over the last 50years, the schistosomiasis control program in China has made great strides in reducing prevalence and morbidity, and the Chinese authorities now aim to eliminate the disease nationwide in the next decade. Current Chinese control strategies place particular importance on interventions targeting bovines including: praziquantel treatment, barrier farming to prevent grazing in transmission areas, their replacement with mechanized tractors and possible bovine vaccination. A number of studies have shown that in the period following S. japonicum infection, the worm burden drops sharply in water buffaloes and some other animal hosts such as pigs. This is due to a self-cure phenomenon whereby there is parasite clearance by both immune and non-immune factors. Here we review studies investigating the self-cure effect, paying particular attention to S. japonicum infection in water buffaloes, and discuss its potential impact on the future schistosomiasis control and elimination efforts in China. Further understanding of the mechanism of self-cure in water buffaloes could be important for future schistosome vaccine design and delivery.


Assuntos
Búfalos/parasitologia , Esquistossomose Japônica/prevenção & controle , Zoonoses/prevenção & controle , Animais , Anti-Helmínticos/uso terapêutico , Búfalos/imunologia , Bovinos , China , Reservatórios de Doenças/parasitologia , Feminino , Humanos , Masculino , Praziquantel/uso terapêutico , Schistosoma japonicum/imunologia , Schistosoma japonicum/patogenicidade , Esquistossomose Japônica/imunologia , Esquistossomose Japônica/parasitologia , Zoonoses/imunologia , Zoonoses/parasitologia
16.
Dalton Trans ; 43(1): 222-30, 2014 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-24097353

RESUMO

A series of novel half-zirconocenes containing phosphine-(thio)phenolate chelating ligands of the type Cp'Zr(thf)Cl2[X-2-R(1)-4-R(2)-6-(PPh2)C6H2] (Cp' = C5Me5, 2a: X = O, R(1) = Ph, R(2) = H; 2b: X = O, R(1) = (t)Bu, R(2) = H; 2c: X = O, R(1) = R(2) = (t)Bu; 2d: X = O, R(1) = SiMe3, R(2) = H; 2e: X = S, R(1) = SiMe3, R(2) = H; Cp' = C5H5, 3b: X = O, R(1) = (t)Bu, R(2) = H; 3c: X = O, R(1) = R(2) = (t)Bu; 3d: X = O, R(1) = SiMe3, R(2) = H; 3e: X = S, R(1) = SiMe3, R(2) = H) have been synthesized in high yields (74-85%). These complexes were identified by (1)H, (13)C and (31)P NMR as well as elemental analyses. Structural analysis for 2a-b and 2d revealed that these complexes adopt six-coordinate, distorted octahedral geometry around the zirconium center. These novel half-zirconocenes possessed high catalytic performance for ethylene polymerization at high temperature in the presence of MMAO. The phosphine-phenolate-based Cp* complexes produced high molecular weight polymers (M(W) > 400,000), while the Cp analogues displayed much higher activities at high temperature. Complex 3c with MMAO showed a maximum ethylene polymerization activity of 17,580 kg mol(Zr)(-1) h(-1) at 75 °C. In addition, the Cp based complexes 3b-e could promote ethylene and 1-hexene copolymerization with high activities.

17.
Infect Dis Poverty ; 2(1): 29, 2013 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-24289667

RESUMO

BACKGROUND: With more than two billion people infected worldwide, soil-transmitted helminths (STH) are the most widespread infections. To date, STH control efforts rely predominantly on recurrent mass drug administration (MDA), which does not prevent reinfection. Additional public health measures including novel health educational tools are required for more sustained integrated control of STH. We describe the development of an educational cartoon video (The Magic Glasses) targeting STH infections in Chinese schoolchildren and its pilot testing in China.We applied an extensive community-based mixed methods approach involving input from the target group of 9-10 year old schoolchildren and key informants, such as teachers, doctors and parents, in order to identify potential STH infection risks in the study area and to formulate key messages for the cartoon. The development of the educational cartoon included three major steps: formative research, production, and pilot testing and revision. RESULTS: We found that most adults and approximately 50% of the schoolchildren were aware of roundworm (Ascaris) infection, but knowledge of transmission, prevention and treatment of STH was poor. Observations in the study area showed that unhygienic food practices, such as eating raw and unwashed fruit or playing in vegetable gardens previously fertilised with human faeces, posed major STH infection risks. CONCLUSIONS: It was crucial to assess the intellectual, emotional, social and cultural background of the target population prior to video production in order to integrate the key messages of the cartoon into everyday situations. Overall, our strategy for the development of the cartoon and its incorporation into a health education package proved successful, and we provide a summary of recommendations for the development of future educational videos based on our experiences in China.

18.
PLoS Negl Trop Dis ; 7(3): e2122, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23516656

RESUMO

INTRODUCTION: More than 80% of schistosomiasis patients in China live in the lake and marshland regions. The purpose of our study is to assess the effect of a comprehensive strategy to control transmission of Schistosoma japonicum in marshland regions. METHODOLOGY/PRINCIPAL FINDINGS: In a cluster randomized controlled trial, we implemented an integrated control strategy in twelve villages from 2009 through 2011 in Gong'an County, Hubei Province. The routine interventions included praziquantel chemotherapy and controlling snails, and were implemented in all villages. New interventions, mainly consisting of building fences to limit the grazing area for bovines, building safe pastures for grazing, improving the residents' health conditions and facilities, were only implemented in six intervention villages. Results showed that the rate of S. japonicum infection in humans, bovines, snails, cow dung and mice in the intervention group decreased from 3.41% in 2008 to 0.81% in 2011, 3.3% to none, 11 of 6,219 to none, 3.9% to none and 31.7% to 1.7%, respectively (P<0.001 for all comparisons). In contrast, there were no statistically significant reductions of S. japonicum infection in humans, bovines and snails from 2008 to 2011 in the control group (P>0.05 for all comparisons). Moreover, a generalized linear model showed that there was a higher infection risk in humans in the control group than in the intervention group (OR = 1.250, P = 0.001) and an overall significant downward trend in infection risk during the study period. CONCLUSIONS/SIGNIFICANCE: The integrated control strategy, designed to reduce the role of bovines and humans as sources of S. japonicum infection, was highly effective in controlling the transmission of S. japonicum in marshland regions in China. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR-PRC-12002405.


Assuntos
Doenças dos Bovinos/tratamento farmacológico , Doenças dos Bovinos/transmissão , Esquistossomose Japônica/transmissão , Esquistossomose Japônica/veterinária , Zoonoses/epidemiologia , Zoonoses/transmissão , Adulto , Animais , Anti-Helmínticos/uso terapêutico , Bovinos , Doenças dos Bovinos/parasitologia , Doenças dos Bovinos/prevenção & controle , China , Fezes/parasitologia , Feminino , Humanos , Masculino , Camundongos , Pessoa de Meia-Idade , Praziquantel/uso terapêutico , Prevalência , Roedores/parasitologia , População Rural , Schistosoma japonicum/isolamento & purificação , Esquistossomose Japônica/tratamento farmacológico , Esquistossomose Japônica/prevenção & controle , Caramujos/parasitologia , Zoonoses/parasitologia
19.
Dalton Trans ; 42(2): 499-506, 2013 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-23073181

RESUMO

A series of novel monochloro half-zirconocene complexes containing phosphine oxide-(thio)phenolate chelating ligands of the type, ClCp'Zr[X-2-R(1)-4-R(2)-6-(Ph(2)P=O)C(6)H(2)](2) (Cp' = C(5)H(5), 2a: X = O, R(1) = Ph, R(2) = H; 2b: X = O, R(1) = F, R(2) = H; 2c: X = O, R(1) = (t)Bu, R(2) = H; 2d: X = O, R(1) = R(2) = (t)Bu; 2e: X = O, R(1) = SiMe(3), R(2) = H; 2f: X = S, R(1) = SiMe(3), R(2) = H; Cp' = C(5)Me(5), 2g: X = O, R(1) = SiMe(3), R(2) = H), have been synthesized in high yields. These complexes were identified by (1)H {(13)C} NMR and elemental analyses. Structures for 2b, 2c and 2f were further confirmed by X-ray crystallography. Structural characterization of these complexes reveals crowded environments around the zirconium. Complexes 2b and 2c adopt six-coordinate, distorted octahedral geometry around the zirconium center, in which the equatorial positions are occupied by three oxygen atoms of two chelating phosphine oxide-bridged phenolate ligands and a chlorine atom. The cyclopentadienyl ring and one oxygen atom of the ligand are coordinated on the axial position. Complex 2f also folds a six-coordinate, distorted octahedral geometry around the Zr center, consisting of a Cp-Zr-O (in P=O) axis [177.16°] and a distorted plane of two sulfur atoms and one oxygen atom of two chelating phosphine oxide-bridged thiophenolate ligands as well as a chlorine atom. When activated by modified methylaluminoxane (MMAO), all the complexes exhibited high activities towards ethylene polymerization at high temperature (75 °C), giving high molecular weight polymers with unimodal molecular weight distribution. The formation of 14-electron, cationic metal alkyl species might come from the Zr-O (in phenol ring) bond cleavage based on the DFT calculations study.

20.
Dalton Trans ; 41(39): 11999-2010, 2012 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-22930203

RESUMO

A series of 2-(2-benzhydrylbenzenamino)pyridine ligands (L1­L13) was synthesized and used as bidentate N^N ligands with nickel halides to afford the corresponding nickel dihalide complexes L(2)Ni(2)Cl(4) C1­C13 and L(2)NiBr(2) D1­D13. All ligands and complexes were characterized by IR and NMR spectroscopy, and by elemental analysis. The molecular structures of the representative complexes C1·2CH(3)OH, C5·2H(2)O, D4, D7 and D9 were confirmed by single-crystal X-ray diffraction studies. Upon activation with either methylaluminoxane (MAO) or ethylaluminium sesquichloride (Et(3)Al(2)Cl(3), EASC), these nickel pre-catalysts exhibited high activities (up to the range of 10(7) g mol(-1) (Ni) h(-1)) towards ethylene polymerization, producing branched polyethylenes with narrow polydispersity.

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