1,142 research outputs found
A Complex Stereochemical Relay Approach To The Antimalarial Alkaloid Ocimicide A1. Evidence For A Structural Revision
Ocimicide A1 (1) and the semisynthetic derivative ocimicide A2 (2) are highly potent antimalarial agents efficacious against chloroquine-sensitive and -resistant Plasmodium falciparum strains with IC50 values in the nanomolar and picomolar range, respectively. Members of this family have demonstrated radical cure in rhesus monkeys, without detectable toxicity, but their structure–function relationships and mechanism of action are unknown. Herein we describe a twelve-step synthesis of an advanced N-acylated pentacyclic precursor to the proposed structure of 1 (11% overall yield). Instability and poor P. falciparum growth inhibition of the corresponding free donor–acceptor cyclopropylamine, and large discrepancies between reported and both experimental and DFT-calculated 13C chemical shifts and coupling constants, suggest that substantial revision of the proposed structures may be necessary
Application of Electrical Properties to Differentiate Lard From Tallow and Palm Oil
This study aimed to differentiate lard from tallow and palm oil based on its electrical properties, namely conductance, impedance and capacitance. These properties were measured at spectra frequencies of 4.20 to 5.00 MHz in room temperature (26-27 oC). Statistic multivariate that consist on principal component analysis (PCA) and cluster analysis (CA) were used to evaluate the data. The results showed that lard and tallow can be differentiated using whole parameters electrical properties of materials. On the other hand, lard and palm oil can only be differentiated using part of the material electrical properties. Good performance of differentiation process was obtained using PCA model at 4.91 to 4.98 MHz. The first two components of PCA, which was derived from conductance, impedance and capacitance, contributed more than 90% of the total variances. CA showed that lard and tallow are different groups based on the Euclidean distance of each electrical properties. This technique can be potentially developed as an electrical sensor for differentiation lard to tallow and palm oil
Precise nondivergent analytic formulas for the radiative corrections to the beta energy spectrum in hyperon semileptonic decays over the entire Dalitz plot
Very accurate analytical expressions for the radiative corrections of
unpolarized hyperons semileptonic decays of charged and neutral baryons have
been obtained in the recent past. Some of these formulas contain logarithmic
singularities at the edges of the Dalitz plot for the three- and four-body
decays. These singularities are analyzed and integrated analytically to obtain
new divergentless formulas for the energy spectrum of the produced beta
particle. The new equations contain terms of the order alpha times the momentum
transfer, are applicable to any beta decay process and are suitable for a
model-independent experimental analysis.Comment: 22 pages, 4 figure
Identifikasi Akses Masyarakat terhadap Pemanfaatan Sumberdaya Alam (Studi Kasus di Desa Karang Tengah Kecamatan Babakan Madang Kabupaten Bogor)
Conservation areas have an important role for the preservation of the surrounding ecosystem. Nature Park is one of the areas Conservation Areas which have an important function for life support system, preserve the diversity of plant and animal species and sustainable use of natural resources and ecosystems. The existence of the community around the region have an important role for the preservation of the region. This study aims to identify the access made public in obtaining, control and manage access to the use of natural resources around the area. The method used is a case study, in which data collection is done through in-depth interviews and participant observation. Data were analyzed using the access theory results show that the public has access to the processing area where the land around Region Natural Park of Mount Pancar has a level of encroachment or work area without permission is still quite high. Public access and utilization of acquiring land is before the area designated as TWA and ruled for generations, land control is not done specifically and communities manage the land and the potential that exists with the mastery of the blocks that have a high potential of natural resources. Seen most percentage of land cultivated by the community that is in the block of Mount Pancar as much as 24.41% and at least at the block Paniisan only 5:08%
Inadvertent positioning of suprapubic catheter in urethra: a serious complication during change of suprapubic cystostomy in a spina bifida patient - a case report
Spin-Wave Description of Haldane-gap antiferromagnets
Modifying the conventional antiferromagnetic spin-wave theory which is
plagued by the difficulty of the zero-field sublattice magnetizations diverging
in one dimension, we describe magnetic properties of Haldane-gap
antiferromagnets. The modified spin waves, constituting a grand canonical
bosonic ensemble so as to recover the sublattice symmetry, not only depict well
the ground-state correlations but also give useful information on the
finite-temperature properties.Comment: to be published in J. Phys. Soc. Jpn. Vol. 72, No. 4 (2003
Long-term result of Memokath urethral sphincter stent in spinal cord injury patients
BACKGROUND: Memokath urethral sphincter stents are used to facilitate bladder emptying in patients with spinal cord injury, but long term follow-up has not been reported. METHODS: Case series of ten men with spinal cord injury who underwent insertion of Memokath stents and were followed for up to nine years. RESULTS: Within four years, the stent had to be removed in nine out of ten patients because of: extensive mucosal proliferation causing obstruction to the lumen of the stent; stone around the proximal end of the stent, incomplete bladder emptying, and recurrent urinary infections; migration of the stent into the bladder related to digital evacuation of bowels; large residual urine; concretions within the stent causing obstruction to flow of urine, and partial blockage of the stent causing frequent episodes of autonomic dysreflexia. In one patient the stent continued to function satisfactorily after nine years. CONCLUSIONS: The Memokath stent has a role as a temporary measure for treatment of detrusor-sphincter dyssynergia in selected SCI patients who do not get recurrent urinary infection and do not require manual evacuation of bowels
Nuclear Magnetic Relaxation in the Haldane-Gap Antiferromagnet Ni(C_2_H_8_N_2_)_2_NO_2_(ClO_4_)
A new theory is proposed to interpret nuclear spin-lattice relaxation-time
(T_1_) measurements on the spin-1 quasi-one-dimensional Heisenberg
antiferromagnet Ni(C_2_H_8_N_2_)_2_NO_2_(ClO_4_) (NENP). While Sagi and Affleck
pioneeringly discussed this subject in terms of field-theoretical languages,
there is no theoretical attempt yet to explicitly simulate the novel
observations of 1/T_1_ reported by Fujiwara et al.. By means of modified spin
waves, we solve the minimum of 1/T_1_ as a function of an applied field,
pending for the past decade.Comment: to be published in J. Phys. Soc. Jpn. 73, No. 4 (2004
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