261 research outputs found
Elastic State Induced Energy Gap Variation in ZnTe/ZnMgTe Core/Shell Nanowires
The zinc telluride (ZnTe) nanowires grown recently are covered with the ZnMgTe shell. As a result of addition of magnesium the ZnMgTe lattice is expanded with respect to pure ZnTe lattice. From the lattice mismatch between the ZnMgTe shell and ZnTe nanowire core the internal strain and stress are created. Depending on the shell thickness and the Mg content in the shell the optical emission exhibits a considerable energy shift. To estimate this effect, at least qualitatively, the elastic state of the nanowire is calculated.An analysis of the state of strain and stress in the core-shell nanowire within linear elasticity, using an analogy with thermal stresses is presented, in the similar way as it is applied, e.g. in hygro-mechanics. The suitable system of the differential Lam´e-Navier’s type equations is derived, and its solution for the axially symmetric problem is given. The jump of stress at the core-shell boundary is determined
Influence of exciton spin relaxation on the photoluminescence spectra of semimagnetic quantum dots
We present a comprehensive experimental and theoretical studies of
photoluminescence of single CdMnTe quantum dots with Mn content x ranging from
0.01 to 0.2. We distinguish three stages of the equilibration of the exciton-Mn
ion spin system and show that the intermediate stage, in which the exciton spin
is relaxed, while the total equilibrium is not attained, gives rise to a
specific asymmetric shape of the photoluminescence spectrum. From an excellent
agreement between the measured and calculated spectra we are able to evaluate
the exciton localization volume, number of paramagnetic Mn ions, and their
temperature for each particular dot. We discuss the values of these parameters
and compare them with results of other experiments. Furthermore, we analyze the
dependence of average Zeeman shifts and transition linewidths on the Mn content
and point out specific processes, which control these values at particular Mn
concentrations.Comment: submitted to Phys. Rev.
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Contains research objectives and reports on one research projects.Lincoln Laboratory, Purchase Order DDL B-00368U. S. ArmyU. S. NavyU. S. Air Force under Air Force Contract AF19(604)-7400National Institutes of Health (Grant MH-04737-02
Differences in oestrogen and progesterone receptors, HER-2, p53 expression and proliferation in ductal breast cancers in relation to histopathological grade
In case of breast cancer the grade of differentiation and expression of oestrogen
and progesterone receptors falls within the first category of prognostic factors
according to the College of American Pathologists. HER-2, p53 and Ki67 belong
to the second category and their significance still awaits confirmation. The aim of
the present study was to examine the relationship between the intensity of expression
of oestrogen receptors (ER), progesterone receptors (PgR), HER-2, p53
and Ki67 in cells of ductal breast cancer of G1, G2 or G3 differentiation grade. In
paraffin sections of 60 ductal breast cancers (20 cases in G1, 20 in G2 and 20 in
G3), immunocytochemical reactions were performed to detect the expression of
ER, PgR, HER-2, p53 and Ki67. Following a semi-quantitative appraisal of the
preparations under examination, appropriate statistical tests were used to document
significant relationships. We noted significant positive correlations between
ER and PgR (the entire group studied, G1–3, and the G1 group), HER-2 and p53
(G2) and between p53 and Ki67 expression (G2). Significant negative correlations
were found between ER and p53 (G1–3), PgR and p53 (G1–3, G1, G3) and between
PgR and Ki67 (G1–3, G2). The studies performed demonstrated distinct
relationships between the expression intensity of various proteins in tumour cells
in relation to the grade of differentiation of the tumour. We also showed that
a parallel determination of ER, PgR and p53 expression may carry high predictive
value as to response to tamoxifen treatment
Automated analysis of atrial late gadolinium enhancement imaging that correlates with endocardial voltage and clinical outcomes: A 2-center study
This work was supported by the British Heart Foundation PG/10/37/28347, RG/10/11/28457, NIHR Biomedical Research Centre funding, and the ElectroCardioMaths Programme of the Imperial BHF Centre of Research Excellence
Magnetic polaron formation and exciton spin relaxation in single CdMnTe quantum dots
We study the formation dynamics of a spontaneous ferromagnetic order in
single self-assembled CdMnTe quantum dots. By measuring time-resolved
photoluminescence, we determine the formation times for QDs with Mn ion
contents x varying from 0.01 to 0.2. At low x these times are orders of
magnitude longer than exciton spin relaxation times evaluated from the decay of
photoluminescence circular polarization. This allows us to conclude that the
direction of the spontaneous magnetization is determined by a momentary Mn spin
fluctuation rather than resulting from an optical orientation. At higher x, the
formation times are of the same order of magnitude as found in previous studies
on higher dimensional systems. We also find that the exciton spin relaxation
accelerates with increasing Mn concentration.Comment: sent to Physical Review
Assessment and prevalence of depression in women 45–55 years of age visiting gynecological clinics in Poland
¶The aims of the Polish survey were to assess efficacy of screening for depression in gynecological practice and to estimate prevalence of depressive disorders in midlife women visiting gynecologists. The study included 2262 female outpatients aged 45–55, who were screened by 120 gynecologists throughout Poland. Patients completed the Beck’s Depression Inventory (BDI) and were assessed by gynecologists to verify the presence of symptoms of a current Depressive Episode according to ICD-10 diagnostic criteria. Patients who obtained a score of 12 points or more on the BDI were referred for psychiatric evaluation, including the modified version of Mini International Neuropsychiatric Interview (MINI). The study showed that gynecologists in Poland are able to perform screenings for depression effectively in outpatient settings. Results also suggested that about 19% of women aged 45 to 55 years visiting gynecologists may suffer from depressive disorders.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41736/1/737_2003_Article_019.pd
Eudor-a: a Naturalistic, European Multi-centre Clinical Study of Edor Test in Adult Patients with Primary Depression
Introduction: Previous findings suggested that electrodermal hyporeactivity has a high sensitivity (up to 97%)
and high raw specificity (up to 98%) for suicide.
Aim: To evaluate prevalence, sensitivity and specificity of electrodermal hyporeactivity for suicide
and suicide attempt, with and without death intent and with violent method or not, in adult patients
with a primary diagnosis of depression.
Methods: At each study site at least 100 patients with a primary diagnosis of depression, also in remission,
will be recruited. Depressive symptomatology will be evaluated through the Montgomery-Asberg Depression
Scale. Previous suicide attempts will be registered and the death intent of the worst attempt will be rated
according to the first eight items of the Beck Suicide Intent Scale. The risk of suicide will be assessed
according to rules and traditions at the centre. The EDOR Test (ElectroDermal Orienting Reactivity) will be
performed. Two fingers are put on gold electrodes. Through headphones a moderately strong tone is
presented now and then during the test. Sensors located within the electrodes are able to register the
electrodermal response to those tones, measuring the skin conductance (i.e. electrodermal activity from
sweat gland activity). Each patient will be followed up for one year for actions of intentional self-harm that
require medical care and for suicide. The death intent will also be rated.
Expected results: It is expected that the EDOR test detects a previously unknown neuropsychological
dysfunction that is independent of the depressive state and can predict suicidality with a high sensitivity and
specificit
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