626 research outputs found
Process controls introduction of selected impurities into semiconductor wafers
Modified three-step process controls the concentration of lithium diffused as a dopant into the base region of a diffused n-on-p silicon solar cell wafer. Part of the surface layer of the base region of the p-type silicon containing the diffused dopant is removed, prior to redistributing the remaining portion of the dopant into the bulk of the wafer
Psychospiritual Development of Female Adoptees Raised Within a Closed Adoption System: A Theoretical Model Within a Feminist and Jungian Perspective
This article proposes a transpersonal theoretical model suggesting that the embodiment of
the voice of the feminine is a significant catalyst for awakening the psychological and spiritual
growth and development of female adoptees. Existing Jungian and feminist theoretical
models regarding the psychological and spiritual implications for a female adoptee raised
within a closed adoption system will be discussed. The author will share her adopted voice
about her spiritual and psychological process toward finding wholeness using a hermeneutical
process of inquiry. The voices of birth mothers who relinquished their children will also be
included. Voice is then explored to be an essential component of the embodied feminine,
in turn becoming a catalyst of psychospiritual growth and developmental awakening for
female adoptees
Lift distribution and longitudinal stability of an airplane
The preliminary calculation of the airplane polar and hence of the flight performances and characteristics rests on the assumption of an elliptical lift distribution at all altitudes. For large angles of attack below C(sub a (sub max)), this method of calculation yields no satisfactory agreement with measurements made in flight. An attempt is made to eliminate the errors in the preliminary calculation by the assumption of a disturbance of the lift distribution in this angle-of-attack range, which is so important for the constructor. An explanation is also given of the great differences found in flight with and without propeller slipstream
Airplane drag
It has been less well understood that the induced drag (or, better said, the undesired increase in the induced drag as compared with the theoretical minimum calculated by Prandtl) plays a decisive role in the process of taking off and therefore in the requisite engine power. This paper seeks to clarify the induced drag
Using genome editing to investigate deletional mutations associated with elevated foetal haemoglobin as a novel approach for treating β-haemoglobinopathies
The benign condition Hereditary Persistence of Foetal Haemoglobin (HPFH) alleviates -haemoglobinopathies, such as sickle cell disease and -thalassemia. HPFH can be associated with point mutations in the foetal globin promoters that disrupt the binding of the repressors BCL11A or LRF or create de novo binding sites for activators. HPFH is also associated with an extensive range of deletions within the -globin locus that reside downstream of the foetal HBG2 gene. Numerous mechanisms have been proposed to explain how downstream deletions can boost the expression of the foetal globin genes, including the deletion of silencer elements, deletion of genes encoding non-coding RNA, and bringing downstream enhancer elements into proximity with the foetal globin gene promoters. Here we systematically analysed the deletions associated with both HPFH and a related condition known as -thalassemia and propose a unifying mechanism. We found that in all cases where foetal globin is up-regulated the proximal adult -globin promoter is deleted. We used CRISPR gene editing to delete or disrupt transcription factor binding sites within the promoter and found that virtually all deletions that reduce HBB promoter activity, result in elevated foetal globin expression. These results fit with previous models where the foetal and adult globin genes compete for the distal locus control element. Under this model by disrupting the adult globin promoter, the foetal globin genes expression would be reactivated by allowing the foetal globin gene to better compete for the locus control element. We also found that a disruption of transcription factor binding sites by point mutations did not exert the same effect, suggesting that point mutations do not sufficiently disrupt competition for the locus control element. Our findings suggest that targeting the HBB promoter might be explored to elevate foetal globin and reduce sickle globin expression as a treatment for sickle cell disease
Image quality optimization, via application of contextual contrast sensitivity and discrimination functions
What is the best luminance contrast weighting-function for image quality optimization? Traditionally measured contrast sensitivity functions (CSFs), have been often used as weighting-functions in image quality and difference metrics. Such weightings have been shown to result in increased sharpness and perceived quality of test images. We suggest contextual CSFs (cCSFs) and contextual discrimination functions (cVPFs) should provide bases for further improvement, since these are directly measured from pictorial scenes, modeling threshold and suprathreshold sensitivities within the context of complex masking information. Image quality assessment is understood to require detection and discrimination of masked signals, making contextual sensitivity and discrimination functions directly relevant. In this investigation, test images are weighted with a traditional CSF, cCSF, cVPF and a constant function. Controlled mutations of these functions are also applied as weighting-functions, seeking the optimal spatial frequency band weighting for quality optimization. Image quality, sharpness and naturalness are then assessed in two-alternative forced-choice psychophysical tests. We show that maximal quality for our test images, results from cCSFs and cVPFs, mutated to boost contrast in the higher visible frequencies
Genetic analysis reveals a complex regulatory network modulating CBF gene expression and Arabidopsis response to abiotic stress
Arabidopsis CBF genes (CBF1–CBF3) encode transcription factors having a major role in cold acclimation, the adaptive process whereby certain plants increase their freezing tolerance in response to low non-freezing temperatures. Under these conditions, the CBF genes are induced and their corresponding proteins stimulate the expression of target genes configuring low-temperature transcriptome and conditioning Arabidopsis freezing tolerance. CBF2 seems to be the most determinant of the CBFs since it also regulates CBF1 and CBF3 expression. Despite the relevance of CBF genes in cold acclimation, little is known about the molecular components that control their expression. To uncover factors acting upstream of CBF2, mutagenized Arabidopsis containing the luciferase reporter gene under the control of the CBF2 promoter were screened for plants with de-regulated CBF2 expression. Here, the identification and characterization of five of these mutants, named acex (altered CBF2 expression), is presented. Three mutants show increased levels of cold-induced CBF2 transcripts compared with wild-type plants, the other two exhibiting reduced levels. Some mutants are also affected in cold induction of CBF1 and CBF3. Furthermore, the mutants characterized display unique phenotypes for tolerance to abiotic stresses, including freezing, dehydration, and high salt. These results demonstrate that cold induction of CBF2 is subjected to both positive and negative regulation through different signal transduction pathways, some of them also mediating the expression of other CBF genes as well as Arabidopsis responses to abiotic stresses
- …