6 research outputs found
Characterization of Anopheles gambiae s.l. and insecticide resistance profile relative to physicochemical properties of breeding habitats within Accra Metropolis, Ghana
Malaria is endemic in Ghana as in most countries of sub-Saharan Africa. This study was conducted to characterize Anopheles gambiae s.l. and determine pyrethroid resistance profiles relative to physicochemical properties of breeding habitats in Accra, Ghana. Eight aquatic habitats containing Anopheles larvae were identified and from each habitat, larvae and water were sampled. Adult An. gambiae reared from larvae were morphologically identified and tested for permethrin (0.75%) and deltamethrin (0.05%) resistance using WHO bioassay method. An. gambiae s.s. found were identified to their molecular levels and kdr mutation detected using PCR-based methods. Twenty-nine physicochemical parameters of each water sample were measured and their levels connected with pyrethroid resistance and proportions of An. gambiae s.s. molecular forms in habitats. A total of 2,257 mosquitoes were morphologically identified as An. gambiae s.l. and all 224 processed for PCR were identified as An. gambiae s.s., of which 56.46% and 43.54% were M and S-forms, respectively. Both forms occurred in sympatry in all larval habitats and no S/M hybrids were detected. However, M-form larvae were in high proportion in polluted habitats than the S-form. An. gambiae s.s. was highly resistant to both deltamethrin and permethrin with mortality rates of 42.98-70.0% and 6.5-20.0% respectively. The frequency of kdr mutation was 60.5 % (n=195). This mutation occurred in both S and M-forms, but was mainly associated with the S-form (X2=10.92, df =1, P=0.001). Carbonate and pH were both selected in discriminant function analysis as best predictors of high proportion of M-form in the habitats. The adaptation of An. gambiae s.s. in polluted aquatic habitats coupled with occurrence of insecticide resistance is quite alarming particularly for urban malaria control and needs further exploration in a wider context
Characterization of Anopheles gambiae s.l. and insecticide resistance profile relative to physicochemical properties of breeding habitats within Accra Metropolis, Ghana
Malaria is endemic in Ghana as in most countries of sub-Saharan Africa.
This study was conducted to characterize Anopheles gambiae s.l. and
determine pyrethroid resistance profiles relative to physicochemical
properties of breeding habitats in Accra, Ghana. Eight aquatic habitats
containing Anopheles larvae were identified and from each habitat,
larvae and water were sampled. Adult An. gambiae reared from larvae
were morphologically identified and tested for permethrin (0.75%) and
deltamethrin (0.05%) resistance using WHO bioassay method. An. gambiae
s.s. found were identified to their molecular levels and kdr mutation
detected using PCR-based methods. Twenty-nine physicochemical
parameters of each water sample were measured and their levels
connected with pyrethroid resistance and proportions of An. gambiae
s.s. molecular forms in habitats. A total of 2,257 mosquitoes were
morphologically identified as An. gambiae s.l. and all 224 processed
for PCR were identified as An. gambiae s.s., of which 56.46% and 43.54%
were M and S-forms, respectively. Both forms occurred in sympatry in
all larval habitats and no S/M hybrids were detected. However, M-form
larvae were in high proportion in polluted habitats than the S-form.
An. gambiae s.s. was highly resistant to both deltamethrin and
permethrin with mortality rates of 42.98-70.0% and 6.5-20.0%
respectively. The frequency of kdr mutation was 60.5 % (n=195). This
mutation occurred in both S and M-forms, but was mainly associated with
the S-form (X2=10.92, df =1, P=0.001). Carbonate and pH were both
selected in discriminant function analysis as best predictors of high
proportion of M-form in the habitats. The adaptation of An. gambiae
s.s. in polluted aquatic habitats coupled with occurrence of
insecticide resistance is quite alarming particularly for urban malaria
control and needs further exploration in a wider context
Formation of Covalently Bonded Polycyclic Hydrocarbon Ions by Intracluster Polymerization of Ionized Ethynylbenzene Clusters
Here we report a detailed study aimed
at elucidating the mechanism
of intracluster ionic polymerization following the electron impact
ionization of van der Waals clusters of ethynylbenzene (C<sub>8</sub>H<sub>6</sub>)<sub><i>n</i></sub> generated by a supersonic
beam expansion. The structures of the C<sub>16</sub>H<sub>12</sub>, C<sub>24</sub>H<sub>18</sub>, C<sub>32</sub>H<sub>24</sub>, C<sub>40</sub>H<sub>30</sub>, and C<sub>48</sub>H<sub>36</sub> radical
cations resulting from the intracluster ion–molecule addition
reactions have been investigated using a combination of mass-selected
ion dissociation and ion mobility measurements coupled with theoretical
calculations. Noncovalent structures can be totally excluded primarily
because the measured fragmentations cannot result from noncovalent
structures, and partially because of the large difference between
the measured collision cross sections and the calculated values corresponding
to noncovalent ion–neutral complexes. All the mass-selected
cluster ions show characteristic fragmentations of covalently bonded
molecular ions by the loss of stable neutral fragments such as CH<sub>3</sub>, C<sub>2</sub>H, C<sub>6</sub>H<sub>5</sub>, and C<sub>7</sub>H<sub>7</sub>. The population of the C<sub>16</sub>H<sub>12</sub> dimer ions is dominated by structural isomers of the type (C<sub>6</sub>H<sub>5</sub>)CCCH<sup><b>•+</b></sup>CH(C<sub>6</sub>H<sub>5</sub>), which can grow by the
sequential addition of ethynylbenzene molecules, in addition to some
contributions from cyclic isomers such as the 1,3- or 1,4-diphenyl
cyclobutadiene ions. Similarly, two major covalent isomers have been
identified for the C<sub>24</sub>H<sub>18</sub> trimer ions: one that
has a blocked cyclic structure assigned to 1,2,4- or 1,3,5-triphenylbenzene
cation, and a second isomer of the type (C<sub>6</sub>H<sub>5</sub>)CCC(C<sub>6</sub>H<sub>5</sub>)CHCH<sup><b>•+</b></sup>CH(C<sub>6</sub>H<sub>5</sub>) where the covalent addition of further ethynylbenzene molecules
can occur. For the larger ions such as C<sub>32</sub>H<sub>24</sub>, C<sub>40</sub>H<sub>30</sub>, and C<sub>48</sub>H<sub>36</sub>,
the major isomers present involve the growing oligomer sequence (C<sub>6</sub>H<sub>5</sub>)CC[C(C<sub>6</sub>H<sub>5</sub>)CH]<sub><i>n</i></sub>CH<sup><b>•+</b></sup>CH(C<sub>6</sub>H<sub>5</sub>) with
different locations and orientations of the phenyl groups along the
chain. In addition, the larger ions contain another family of structures
consisting of neutral ethynylbenzene molecules associated with the
blocked cyclic isomer ions such as the diphenylcyclobutadiene and
triphenylbenzene cations. Low-energy dissociation channels corresponding
to evaporation of ethynylbenzene molecules weakly associated with
the covalent ions are observed in the large clusters in addition to
the high-energy channels corresponding to fragmentation of the covalently
bonded ions. However, in small clusters only high-energy dissociation
channels are observed corresponding to the characteristic fragmentation
of the molecular ions, thus providing structural signatures to identify
the product ions and establish the mechanism of intracluster ionic
polymerization
Reproductive Rights Advocacy: Concentration of effort, dilution of intention
Pascale Allotey and Daniel D. Reidpath discuss the issue of female genital cutting and obstetric fistulae within the context of reproductive rights advocacy. They use these examples to discuss the potential effects on the broader reproductive rights agenda of interventions that focus narrowly on what is often a symptom of unaddressed structural violence. They argue for a broader rights approach rather than simply focusing on ameliorating the specific harm, in order to focus on the more fundamental goal, that is, the promotion of the positive freedoms. Development (2005) 48, 69–74. doi:10.1057/palgrave.development.1100181