146 research outputs found
Kinetics of the photosubstitution of cis-bis(benzonitrile)dichloroplatinum(II) in chloroform
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
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
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
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
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
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
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.)
[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
oleanderÂżs
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
stressÂżas
indicated
by
the
accumulation
of malondialdehyde
(MDA),
a reliable
oxidative
stress
marker
Âżaccompanied
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
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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