89 research outputs found
Improved cellulolytic efficacy in Penicilium decumbens via heterologous expression of Hypocrea jecorina endoglucanase II
Hypocrea jecorina endoglucanase II (Hjegl2) was heterologously expressed in Penicillium decumbens (yielding strain Pd::Hjegl2). After induction in cellulose containing media, strain Pd::Hjeg2 displayed increased carboxymethylcellulase activity (CMCase, 5.77 IU/ml, representing a 21% increase) and cellulose degradation determined with a filter paper assay (FPA, 0.40 IU/ml, 67% increase), as compared to the parent strain. In media supplemented with glucose (2%), Pd::Hjegl2, displayed 51.2-fold and 3-fold higher CMCase and FPA activities, respectively, as compared to the parent strain. No changes in the expression levels of the four main native cellulase genes of P. decumbens (Pdegl1, Pdegl2, Pdcbh1, and Pdcbh2) were noted between the transformant and wild-type strains. These data support the idea that Hjegl2 cleaves both internal and terminal glycosidic residues, in a relatively random and processive manner. In situ polyacrylamide gelactivity staining of extracts derived from wild-type and Pd::Hjegl2 revealed two additional active fractions in the latter strain; one with a molecular mass ~50-65 KDa and another ~80-116 kDa
Analysis of corrections to the eikonal approximation
Various corrections to the eikonal approximations are studied for two- and
three-body nuclear collisions with the goal to extend the range of validity of
this approximation to beam energies of 10 MeV/nucleon. Wallace's correction
does not improve much the elastic-scattering cross sections obtained at the
usual eikonal approximation. On the contrary, a semiclassical approximation
that substitutes the impact parameter by a complex distance of closest approach
computed with the projectile-target optical potential efficiently corrects the
eikonal approximation. This opens the possibility to analyze data measured down
to 10 MeV/nucleon within eikonal-like reaction models.Comment: 10 pages, 8 figure
Plant microRNAs: Biogenesis, Homeostasis, and Degradation
MicroRNAs (miRNAs), a class of endogenous, tiny, non-coding RNAs, are master regulators of gene expression among most eukaryotes. Intracellular miRNA abundance is regulated under multiple levels of control including transcription, processing, RNA modification, RNA-induced silencing complex (RISC) assembly, miRNA-target interaction, and turnover. In this review, we summarize our current understanding of the molecular components and mechanisms that influence miRNA biogenesis, homeostasis, and degradation in plants. We also make comparisons with findings from other organisms where necessary
Leiomyosarcoma of the inferior vena cava level II involvement: curative resection and reconstruction of renal veins
Akt/mTOR mediated induction of bystander effect signaling in a nucleus independent manner in irradiated human lung adenocarcinoma epithelial cells
Colossal optical anisotropy from atomic-scale modulations
In modern optics, materials with large birefringence ({\Delta}n, where n is
the refractive index) are sought after for polarization control (e.g. in wave
plates, polarizing beam splitters, etc.), nonlinear optics and quantum optics
(e.g. for phase matching and production of entangled photons),
micromanipulation, and as a platform for unconventional light-matter coupling,
such as Dyakonov-like surface polaritons and hyperbolic phonon polaritons.
Layered "van der Waals" materials, with strong intra-layer bonding and weak
inter-layer bonding, can feature some of the largest optical anisotropy;
however, their use in most optical systems is limited because their optic axis
is out of the plane of the layers and the layers are weakly attached, making
the anisotropy hard to access. Here, we demonstrate that a bulk crystal with
subtle periodic modulations in its structure -- Sr9/8TiS3 -- is transparent and
positive-uniaxial, with extraordinary index n_e = 4.5 and ordinary index n_o =
2.4 in the mid- to far-infrared. The excess Sr, compared to stoichiometric
SrTiS3, results in the formation of TiS6 trigonal-prismatic units that break
the infinite chains of face-shared TiS6 octahedra in SrTiS3 into periodic
blocks of five TiS6 octahedral units. The additional electrons introduced by
the excess Sr subsequently occupy the TiS6 octahedral blocks to form highly
oriented and polarizable electron clouds, which selectively boost the
extraordinary index n_e and result in record birefringence ({\Delta}n > 2.1
with low loss). The connection between subtle structural modulations and large
changes in refractive index suggests new categories of anisotropic materials
and also tunable optical materials with large refractive-index modulation and
low optical losses.Comment: Main text + supplementar
Giant Modulation of Refractive Index from Correlated Disorder
Correlated disorder has been shown to enhance and modulate magnetic,
electrical, dipolar, electrochemical and mechanical properties of materials.
However, the possibility of obtaining novel optical and opto-electronic
properties from such correlated disorder remains an open question. Here, we
show unambiguous evidence of correlated disorder in the form of anisotropic,
sub-angstrom-scale atomic displacements modulating the refractive index tensor
and resulting in the giant optical anisotropy observed in BaTiS3, a
quasi-one-dimensional hexagonal chalcogenide. Single crystal X-ray diffraction
studies reveal the presence of antipolar displacements of Ti atoms within
adjacent TiS6 chains along the c-axis, and three-fold degenerate Ti
displacements in the a-b plane. 47/49Ti solid-state NMR provides additional
evidence for those Ti displacements in the form of a three-horned NMR lineshape
resulting from low symmetry local environment around Ti atoms. We used scanning
transmission electron microscopy to directly observe the globally disordered Ti
a-b plane displacements and find them to be ordered locally over a few unit
cells. First-principles calculations show that the Ti a-b plane displacements
selectively reduce the refractive index along the ab-plane, while having
minimal impact on the refractive index along the chain direction, thus
resulting in a giant enhancement in the optical anisotropy. By showing a strong
connection between correlated disorder and the optical response in BaTiS3, this
study opens a pathway for designing optical materials with high refractive
index and functionalities such as a large optical anisotropy and nonlinearity.Comment: 24 pages, 3 figure
Childhood Sexual Abuse and the Development of Recurrent Major Depression in Chinese Women
Background
Our prior study in Han Chinese women has shown that women with a history of childhood sexual abuse (CSA) are at increased risk for developing major depression (MD). Would this relationship be found in our whole data set? Method
Three levels of CSA (non-genital, genital, and intercourse) were assessed by self-report in two groups of Han Chinese women: 6017 clinically ascertained with recurrent MD and 5983 matched controls. Diagnostic and other risk factor information was assessed at personal interview. Odds ratios (ORs) were calculated by logistic regression. Results
We confirmed earlier results by replicating prior analyses in 3,950 new recurrent MD cases. There were no significant differences between the two data sets. Any form of CSA was significantly associated with recurrent MD (OR 4.06, 95% confidence interval (CI) [3.19–5.24]). This association strengthened with increasing CSA severity: non-genital (OR 2.21, 95% CI 1.58–3.15), genital (OR 5.24, 95% CI 3.52–8.15) and intercourse (OR 10.65, 95% CI 5.56–23.71). Among the depressed women, those with CSA had an earlier age of onset, longer depressive episodes. Recurrent MD patients those with CSA had an increased risk for dysthymia (OR 1.60, 95%CI 1.11–2.27) and phobia (OR 1.41, 95%CI 1.09–1.80). Any form of CSA was significantly associated with suicidal ideation or attempt (OR 1.50, 95% CI 1.20–1.89) and feelings of worthlessness or guilt (OR 1.41, 95% CI 1.02–2.02). Intercourse (OR 3.47, 95%CI 1.66–8.22), use of force and threats (OR 1.95, 95%CI 1.05–3.82) and how strongly the victims were affected at the time (OR 1.39, 95%CI 1.20–1.64) were significantly associated with recurrent MD
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