The link between rejection sensitivity and borderline personality disorder:A systematic review and meta-analysis

OBJECTIVE: People with Borderline Personality Disorder (BPD) may experience heightened rejection sensitivity (RS), a disposition developing from repeated childhood rejecting experiences. It is not known whether the full RS model accounts for the cognitive-affective experiences common in BPD. This systematic review extends upon previous reviews, firstly by assessing the link between childhood rejecting experiences and adult RS, and secondly by considering the link between BPD and RS in both non-clinical and clinical samples.METHOD: Two research questions were devised, and searches based on predetermined criteria were conducted using PsycNET, PubMed, SCOPUS, and Web of Science. Data were extracted by one researcher and 20% was inter-rated, with high levels of agreement. Forty-three papers were systematically reviewed, and 31 included in meta-analysis and meta-regression.RESULTS: Studies assessing the link between childhood rejection and RS are limited; however, emotional abuse and neglect appears linked with RS. Pooled effect sizes suggest RS is linked with BPD (r = .326), with strong effect sizes when comparing clinical and control samples (r = .655). Qualitative synthesis suggests this may be mediated by executive control, although further research is required. The small number of studies considering the full RS model with regard to BPD suggests the interaction between emotional abuse and neglect affects rejection sensitivity; however, outcomes are inconsistent.CONCLUSIONS: Childhood rejection, particularly emotional abuse and neglect, appears to be linked to rejection sensitivity, and rejection sensitivity is linked to BPD. However, this may not be linear. Implications for clinical practice and research are discussed.PRACTITIONER POINTS: Rejection sensitivity is consistently linked with BPD, in clinical and non-clinical samples. Supporting mentalization or improved theory of mind may offer a therapeutic target for this disposition. Considering the causes and effects of rejection sensitivity may offer a non-blaming explanation of interpersonal difficulties in BPD and could be utilized as part of formulation and the therapeutic relationship. However, the possible interaction between emotional abuse and neglect and rejection sensitivity suggests rejection sensitivity is not always apparent for people with BPD. Idiosyncratic formulation should consider this. The literature included in the review is limited to Western populations with a high proportion of females, which may limit generalizability. Measures of rejection sensitivity included in the review were restricted to self-report, which may be subject to bias. Furthermore, measures of childhood rejection were retrospective in nature due to the exclusion of child samples. Further research should consider longitudinal and observational study designs.</p

Affective lability and difficulties with regulation are differentially associated with amygdala and prefrontal response in women with Borderline Personality Disorder

The present neuroimaging study investigated two aspects of difficulties with emotion associated with Borderline Personality Disorder (BPD()): affective lability and difficulty regulating emotion. While these two characteristics have been previously linked to BPD symptomology, it remains unknown whether individual differences in affective lability and emotion regulation difficulties are subserved by distinct neural substrates within a BPD sample. To address this issue, sixty women diagnosed with BPD were scanned while completing a task that assessed baseline emotional reactivity as well as top-down emotion regulation. More affective instability, as measured by the Affective Lability Scale (ALS()), positively correlated with greater amygdala responses on trials assessing emotional reactivity. Greater difficulties with regulating emotion, as measured by the Difficulties with Emotion Regulation Scale (DERS()), was negatively correlated with left inferior frontal gyrus (IFG()) recruitment on trials assessing regulatory ability. These findings suggest that, within a sample of individuals with BPD, greater bottom-up amygdala activity is associated with heightened affective lability. By contrast, difficulties with emotion regulation are related to reduced IFG recruitment during emotion regulation. These results point to distinct neural mechanisms for different aspects of BPD symptomology

Payment Transaction System Using QR Codes

Group project with Muneeb Ahmed, Corey Miner, Sanarya Salah, and Benjamin WodhamsThe purpose of this project is to create a payment transaction system that generates QR codes on a mobile application and website with a specific amount of money decided by the receiver and can be adjusted by the payer. Nowadays people do not carry cash around with them, but they do carry their phones. This project is mainly directed to two different groups of users. The first group is people without a steady income source who live based on donations and might not have a phone to access other methods of payment. The second group is people with jobs where a big portion of what they make is based on tips, such as waiters, doormen, or valet attendants. Our group, Team 18080, proceeded to create the app, starting with prototyping and research, and then actual coding, leading to a fully functioning app on iOS, Android, and on all web browsers. The app interface was created with React Native with an Azure Database securely storing all information. Payments are processed with the Stripe Payment Processor. The website was created with HTML, CSS, and JavaScript

Pathways to high-lethality suicide attempts

The purpose of this study was to develop a model of the trajectory to high-lethality suicidal behavior for individuals with Major Depressive Disorder (MDD) and Borderline Personality Disorder (BPD). An increased number of previous suicide attempts, substance use immediately prior to the attempt, and objective planning were proposed to lead directly to an attempt of higher lethality. Meanwhile, aggression and impulsivity were hypothesized to lead indirectly, through their association with past suicidal behavior, to a higher lethality attempt. Path analysis revealed a revised model that applied only to individuals with BPD. In this final model, impulsivity was found to be significantly associated with higher-lethality suicide attempts and the frequency of an individual's past suicidal behavior. Additionally, the traits of impulsivity and aggression were found to be significantly correlated in the multivariate model. Pathways linking alcohol use at the time of the attempt to the lethality of suicidal behavior and aggression to the frequency of an individual's past suicidal behavior were not found to be significant, and no model using the variables of interest in this study could be determined for individuals with MDD. These results are discussed in light of current theories of suicidal behavior and in terms of their implications for clinical practice

Wide band-gap nanowires for LEDs

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2015.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 133-147).Wide band-gap nanowires composed of GaN and ZnO are promising materials for unique designs and potential efficiency improvement of light emitting diodes (LEDs) for solid state lighting. The large surface-to-volume ratio of nanowires provides facile strain-relaxation such that nanowires can be grown on substrates with a large lattice mismatch and remain free of threading dislocations. Specifically, the growth of wide band-gap nanowires directly on Si substrates is a promising platform for the fabrication of wafer-scale nanowire array-based LEDs. While nanowire-based LEDs have been previously demonstrated, there has been no work directly comparing the different potential designs of nanowire-based LEDs addressing how material-specific properties affect the light extraction and internal quantum efficiency (IQE). Furthermore, for scalable fabrication of nanowire array-based LEDs on Si a large degree of control over the nanowire synthesis is necessary, especially with regard to the nanowire length uniformity, vertical alignment relative to the growth substrate and the nanowire areal density. In this work we directly compare feasible designs for GaN-InGaN nanowire-based LEDs using a combination of photonic simulation and modeling. We compared the directed external quantum efficiency of III-nitride LEDs on silicon based on axial and radial nanowire heterostructures, considering m- and c-directional nanowires. The directed extraction efficiency was calculated using photonic simulations and the IQE was estimated using the A-B-C model. We found that m-directional axial heterostructures have the highest directed extraction efficiency, due to the strong polarization anisotropy of III-nitrides, and display similar IQE as c-directional axial heterostructures. By combining IQE and directed extraction, a range of expected directed external quantum efficiencies (EQEs) reveal that m-directional axial heterostructures have EQEs up to three times that of c-directional axial heterostructures, providing guidelines for the design of future III-nitride nanowire-based LEDs. While III-nitride nanowires are promising candidates, ZnO is an alternative with a higher exciton binding energy and excellent optical properties. To create a platform for the fabrication of ZnO nanowire array-based LEDs on Si, the growth of ZnO was investigated primarily using ZnO solution-processed seed-layers in vapor transport and condensation growth at high temperatures. Due to dependency of the carbothermal reduction of ZnO powder, which acts as the precursor source in the growth, the nanowire areal density was dependent on O2 flow. At low nanowire areal density, growth proceeded in a regime in which continuous nucleation of nanowires occurred throughout the growth, resulting in nanowires with a fixed aspect ratio, but widely varying lengths. At higher nanowire areal densities, the nanowires competed for source precursors in a surface-diffusion limited regime of growth in which the growth rate was dependent upon the nanowire diameter. We observed a critical nucleation diameter for nanowires in the continuous-nucleation regime, which was higher at lower oxygen flow rates. Thus, to achieve length uniformity we developed a two-stage growth method in which nanowires are nucleated at low oxygen flow in the continuous nucleation regime to set the nanowire diameter. In the second stage of growth, where conditions were shifted to the surface-diffusion limited regime, the large diameters set by the first stage of growth were designed to be in the range at which the growth rate does not vary substantially with diameter. The concept of this approach was extended to include control over the nanowire areal density, using sparse ZnO seed-layers. These ZnO nanowires retain excellent optical properties and we observed both demonstrative ptype and n-type doping, dependent on processing conditions, using individual nanowire electrical characterization. Thus, by achieving ZnO nanowire arrays with controlled nanowire areal density, excellent length uniformity and vertical alignment relative to the substrate, we have demonstrated a promising platform for the fabrication of scalable ZnO nanowire array-based LEDs.by Jordan Chesin.Ph. D

Komplexe Analyse gesundheitsrelevanter Faktoren in der Republik Guinea-Bissau

DB Leipzig(101) - Di 1990 B 4165 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Comparing directed efficiency of III-nitride nanowire light-emitting diodes

III-nitride-based nanowires are a promising platform for solid-state lighting. III-nitride nanowires that act as natural waveguides to enhance directed extraction have previously been shown to be free of extended defects even on foreign substrates, such as silicon. While the efficiency of nanowire-based light-emitting diodes (LEDs) has been investigated, there has yet to be a comparison of heterostructures based on nanowires grown in different crystallographic directions. We compared the directed external quantum efficiency (EQE) of III-nitride LEDs on silicon based on axial and radial nanowire heterostructures, considering m- and c-directional nanowires. The directed extraction efficiency was calculated using photonic simulations, and the internal quantum efficiency (IQE) was estimated using the A-B-C model. We found that m-directional axial heterostructures have the highest directed extraction efficiency, due to the strong polarization anisotropy of III-nitrides, and display similar IQE as c-directional axial heterostructures. By combining IQE and directed extraction, a range of directed expected EQEs reveal that m-directional axial heterostructures have EQEs up to three times that of c-directional axial heterostructures, providing guidelines for the design of future nanowire-based LEDs.United States. Dept. of Energy. Office of Basic Energy Sciences (Award DE-SC0001088

Light extraction in individual GaN nanowires on Si for LEDs

GaN-based nanowires hold great promise for solid state lighting applications because of their waveguiding properties and the ability to grow nonpolar GaN nanowire-based heterostructures, which could lead to increased light extraction and improved internal quantum efficiency, respectively. In addition, GaN nanowires can be grown directly on Si substrates, providing an inexpensive and scalable platform for device fabrication. We use finite difference time domain photonic simulations to explore light extraction efficiency enhancement in GaN nanowire-based light-emitting diodes (LEDs) on Si. Emission polarization and the placement of the emission source along the length of the nanowire were taken into consideration. We find that the optimal placement of the emission source is determined by the light reflection at the nanowire-air and nanowire-substrate interfaces and the coupling of emitted radiation into the waveguided modes, resulting in extraction efficiencies of up to 50%. Our approach to optimizing light extraction via simulation techniques can be applied to more realistic large-scale devices to guide experimental work towards nanowire-based LEDs with potentially greater efficiencies than their thin-film counterparts