146 research outputs found

    Kinetics of the photosubstitution of cis-bis(benzonitrile)dichloroplatinum(II) in chloroform

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    Under 254 nm irradiation cis-[Pt(C6H5CN)2Cl2] is converted to H2PtCl6. Absorption of light by both the metal complex and the solvent contribute to the first step of this process, suggested to form HPt(C6H5CN) Cl3. A linear dependence of the reaction rate on light intensity appears to rule out chlorination by trichloromethyl radicals. However, at higher light intensities a higher order dependence on intensity develops, and under 313 nm irradiation is dominant, and a reaction between trichloromethyl radical and the excited state complex is proposed to account for this

    A kinetic study of the photolysis of tris(2,4-pentanedionato)cobalt(III) and bis(2,4-pentanedionato)cobalt(II) in chloroform

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    Under 254nm irradiation in chloroform, Co(acac)3 (Hacac = 2,4-pentanedione) is converted to Co(acac)2 and then to CoCl2. The metal complex is the primary photoactive species in the photoreduction of Co(acac)3, but the photosubstitution of Co(acac)2 appears to occur primarily through absorption of light by the solvent, followed by a chain reaction in which chlorine atoms displace pentanedionyl radicals. The photosubstitution rate law is complex, and the apparent quantum yield (based on total light absorbed) varies with incident light intensity and Co(acac)2 concentration, reaching values as high as 16 under the conditions of this study. Referred only to the light absorbed by CHCL3, the highest quantum yield measured was 150. An observed partial inverse dependence of the photosubstitution rate on the initial concentration of Co(acac)2 is explained in terms of a mechanism in which the pentanedione product competes with Co(acac)2 for an intermediate

    A kinetic study of the photolysis of ethylferrocene in chloroform

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    The photooxidation of ethylferrocene to ethylferricinium ion and tetrachloroferrate in CHCl3 under 254 nm irradiation proceeds through light absorption by both ethylferrocene and chloroform. The products remain in solution at concentrations below 10-3 M. The fraction occurring through a solvent-initiated pathway increases during the course of the reaction. A secondary thermal reaction is responsible for generating tetrachloroferrate from ethylferricinium ion. The rate of the reaction increases during the early stages, and the data throughout the course of the reaction are consistent with the rate law ( afs + bfR)/ (1 + c[R]/[P]-d[R]/[Cl ]), where [R] and [P] are the concentrations of ethylferrocene and ethylferricinium ion, respectively, and Ć’s and Ć’R are the fractions of light absorbed by the solvent and ethylferrocene, respectively

    Does Rotary Pursuit Data Predict Mouse Task Performance? a Pilot Study

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    Knight & Salvendy (1992) suggested that performance of mouse task depends on precision control and arm-hand steadiness. However, the claims lacked empirical support. This pilot study collected rotary pursuit data, measured by time-on-target (TOT), to assess participants' precision control ability. Performance of mouse task was operationalized using a Fitts' pointing task. Stepwise multiple regression revealed target diameter (D), distance amplitude (A), and TOT contributed to the variability of movement time (MT). Despite highly significant relations, the regression coefficients were so small that they offered little practical value. However, the results indicated that precision control ability is indeed predictive of the performance of mouse task. Several recommendations were made for subsequent studies, they include (i) psychomotor ability should be assessed using multiple trials, (ii) a wider range of ID values should be tested with, (iii) a multi-directional Fitts' paradigm should be employed, and (iv) the mouse task should be more representative of the direct manipulation paradigm.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

    The role of Tay indigenous knowledge in climate change adaptation in the Northern Mountainous Region of Vietnam

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    459-472Through generations of observation and experimentation, the Tay people of Bac Kan Province in the Northern Mountainous Region of Vietnam have developed complex farming systems, cultural practices and an indigenous knowledge base well-suited to their environments. Drawing on data collected through surveys, interviews and focus group discussions, this article first documents some of this knowledge and its role in supporting agricultural production. However, this research also uncovered that contemporary climate change is occurring at rates faster than that knowledge base can meaningfully adjust and adapt. Agricultural productivity was found to be greatly reduced, with men seeking off-farm employment to supplement the loss in income. Agrochemical use has soared and resulted in declines in the health of the local population. Village gender dynamics have also shifted and women have taken on the extra burden of farming. This paper posits that if indigenous knowledge was better integrated into adaptation planning and policies, its conservation and application would enhance resiliency to climate change in indigenous communities and beyond. Simultaneously, it also adds that as the nature, speed and severity of climate change in many marginal areas occur at rates faster than indigenous knowledge can adapt, blended forms of knowledge may offer practical solutions

    The role of Tay indigenous knowledge in climate change adaptation in the Northern Mountainous Region of Vietnam

    Get PDF
    Through generations of observation and experimentation, the Tay people of Bac Kan Province in the Northern Mountainous Region of Vietnam have developed complex farming systems, cultural practices and an indigenous knowledge base well-suited to their environments. Drawing on data collected through surveys, interviews and focus group discussions, this article first documents some of this knowledge and its role in supporting agricultural production. However, this research also uncovered that contemporary climate change is occurring at rates faster than that knowledge base can meaningfully adjust and adapt. Agricultural productivity was found to be greatly reduced, with men seeking off-farm employment to supplement the loss in income. Agrochemical use has soared and resulted in declines in the health of the local population. Village gender dynamics have also shifted and women have taken on the extra burden of farming. This paper posits that if indigenous knowledge was better integrated into adaptation planning and policies, its conservation and application would enhance resiliency to climate change in indigenous communities and beyond. Simultaneously, it also adds that as the nature, speed and severity of climate change in many marginal areas occur at rates faster than indigenous knowledge can adapt, blended forms of knowledge may offer practical solutions

    Regulation of proteinaceous effector expression in phytopathogenic fungi

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    Effectors are molecules used by microbial pathogens to facilitate infection via effector-triggered susceptibility or tissue necrosis in their host. Much research has been focussed on the identification and elucidating the function of fungal effectors during plant pathogenesis. By comparison, knowledge of how phytopathogenic fungi regulate the expression of effector genes has been lagging. Several recent studies have illustrated the role of various transcription factors, chromosome-based control, effector epistasis, and mobilisation of endosomes within the fungal hyphae in regulating effector expression and virulence on the host plant. Improved knowledge of effector regulation is likely to assist in improving novel crop protection strategies

    Effects of salinity and drought on growth, ionic relations, compatible solutes and activation of antioxidant systems in oleander (Nerium oleander L.)

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    [EN] Nerium oleander is an ornamental species of high aesthetic value, grown in arid and semi- arid regions because of its drought tolerance, which is also considered as relatively resistant to salt; yet the biochemical and molecular mechanisms underlying oleander¿s stress toler- ance remain largely unknown. To investigate these mechanisms, one-year-old oleander seedlings were exposed to 15 and 30 days of treatment with increasing salt concentratio ns, up to 800 mM NaCl, and to complete withholding of irrigation; growth parameters and bio- chemical markers characteristic of conserved stress-response pathways were then deter- mined in stressed and control plants. Strong water deficit and salt stress both caused inhibition of growth, degradation of photosynthetic pigments, a slight (but statistically signifi- cant) increase in the leaf levels of specific osmolytes, and induction of oxidative stress¿as indicated by the accumulation of malondialdehyde (MDA), a reliable oxidative stress marker ¿accompanied by increases in the levels of total phenolic compounds and antioxidant fla- vonoids and in the specific activities of ascorbate peroxidase (APX) and glutathione reduc- tase (GR). High salinity, in addition, induced accumulation of Na + and Cl - in roots and leaves and the activation of superoxide dismutase (SOD) and catalase (CAT) activities. Apart from anatomical adaptations that protect oleander from leaf dehydration at moderate levels of stress, our results indicate that tolerance of this species to salinity and water deficit is based on the constitutive accumulation in leaves of high concentratio ns of soluble carbohydrates and, to a lesser extent, of glycine betaine, and in the activation of the aforementioned antiox- idant systems. Moreover, regarding specifically salt stress, mechanisms efficiently blocking transport of toxic ions from the roots to the aerial parts of the plant appear to contribute to a large extent to tolerance in Nerium oleanderThis work was financed by internal funds of the Polytechnic University of Valencia to Monica Boscaiu and Oscar Vicente. Dinesh Kumar’s stay in Valencia was financed by a NAMASTE fellowship from the European Union, and Mohamad Al Hassan was a recipient of an Erasmus Mundus pre-doctoral scholarship financed by the European Commission (Welcome Consortium).Kumar, D.; Al Hassan, M.; Naranjo Olivero, MA.; Agrawal, V.; Boscaiu, M.; Vicente, O. (2017). Effects of salinity and drought on growth, ionic relations, compatible solutes and activation of antioxidant systems in oleander (Nerium oleander L.). PLoS ONE. 12(9). doi:10.1371/journal.pone.0185017Se018501712

    Progress and challenges in the vaccine-based treatment of head and neck cancers

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    Head and neck (HN) cancer represents one of the most challenging diseases because the mortality remains high despite advances in early diagnosis and treatment. Although vaccine-based approaches for the treatment of advanced squamous cell carcinoma of the head and neck have achieved limited clinical success, advances in cancer immunology provide a strong foundation and powerful new tools to guide current attempts to develop effective cancer vaccines. This article reviews what has to be rather what has been done in the field for the development of future vaccines in HN tumours
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