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Abstract Background Plants respond to extracellularly perceived abiotic stresses such as low temperature, drought, and salinity by activation of complex intracellular signaling cascades that regulate acclimatory biochemical and physiological changes. Protein kinases are major signal transduction factors that have a central role in mediating acclimation to environmental changes in eukaryotic organisms. In this study, we characterized the function of the sucrose nonfermenting 1-related protein kinase2 (SnRK2) SAPK4 in the salt stress response of rice. Results Translational fusion of SAPK4 with the green fluorescent protein (GFP) showed subcellular localization in cytoplasm and nucleus. To examine the role of SAPK4 in salt tolerance we generated transgenic rice plants with over-expression of rice SAPK4 under control of the CaMV-35S promoter. Induced expression of SAPK4 resulted in improved germination, growth and development under salt stress both in seedlings and mature plants. In response to salt stress, the SAPK4-overexpressing rice accumulated less Na+ and Cl- and showed improved photosynthesis. SAPK4-regulated genes with functions in ion homeostasis and oxidative stress response were identified: the vacuolar H+-ATPase, the Na+/H+ antiporter NHX1, the Cl- channel OsCLC1 and a catalase. Conclusion Our results show that SAPK4 regulates ion homeostasis and growth and development under salinity and suggest function of SAPK4 as a regulatory factor in plant salt stress acclimation. Identification of signaling elements involved in stress adaptation in plants presents a powerful approach to identify transcriptional activators of adaptive mechanisms to environmental changes that have the potential to improve tolerance in crop plants.

Background: Plants respond to extracellularly perceived abiotic stresses such as low temperature, drought, and salinity by activation of complex intracellular signaling cascades that regulate acclimatory biochemical and physiological changes. Protein kinases are major signal transduction factors that have a central role in mediating acclimation to environmental changes in eukaryotic organisms. In this study, we characterized the function of the sucrose nonfermenting 1-related protein kinase2 (SnRK2) SAPK4 in the salt stress response of rice. Results: Translational fusion of SAPK4 with the green fluorescent protein (GFP) showed subcellular localization in cytoplasm and nucleus. To examine the role of SAPK4 in salt tolerance we generated transgenic rice plants with over-expression of rice SAPK4 under control of the CaMV-35S promoter. Induced expression of SAPK4 resulted in improved germination, growth and development under salt stress both in seedlings and mature plants. In response to salt stress, the SAPK4-overexpressing rice accumulated less Na+ and Cl- and showed improved photosynthesis. SAPK4-regulated genes with functions in ion homeostasis and oxidative stress response were identified: the vacuolar H+-ATPase, the Na+/H+ antiporter NHX1, the Cl- channel OsCLC1 and a catalase. Conclusion: Our results show that SAPK4 regulates ion homeostasis and growth and development under salinity and suggest function of SAPK4 as a regulatory factor in plant salt stress acclimation. Identification of signaling elements involved in stress adaptation in plants presents a powerful approach to identify transcriptional activators of adaptive mechanisms to environmental changes that have the potential to improve tolerance in crop plants. [ABSTRACT FROM AUTHOR]

Background: Pre-exposure prophylaxis is a highly effective method of HIV prevention but few women know about it, have access to it, or see it as relevant to them. In 2019, grassroots organization PrEPster piloted a peer-led intervention, MobPrESH (Mobilizing for Pre-Exposure prophylaxis (PrEP) and Sexual Health), across three sites in England, to mobilize for PrEP and sexual health with communities of women and non-binary people most affected by HIV, including Black women and non-binary people, people of colour, migrants, and transgender (trans) women., Objectives: We aimed to explore the accessibility, feasibility, acceptability, and 'fidelity' of MobPrESH, from the perspectives of peer mobilizers and project staff., Methods: We conducted focus group discussions and qualitative interviews with nine peer mobilizers (most identified as Black cisgender (cis) women) and six project staff (including Black and white cis women and non-binary people). We analysed data thematically, iteratively, and inductively, informed by concepts of reproductive and social justice., Results: We present findings in five thematic areas: connecting and relating to situate sexual health discussions, navigating silence and stigma, connecting within and across communities, competing pressures and structural hostilities, and resources and continuity. Community knowledge-building about PrEP is a slow, iterative process that needs investment and creation of trusted spaces that centre communities' needs and concerns. Peer mobilizers and the communities they engaged with had competing demands in their lives, and knowledge-raising about PrEP was impacted by intersecting stigmas, discrimination, and oppressions around HIV status, racism, misogyny, transphobia, homophobia, and anti-sex worker rhetoric., Conclusions: Peer-led PrEP interventions require funding and foregrounding, particularly for women and non-binary people who are Black, trans, migrants, and people of colour, situated relative to their wider health needs, life pressures, and priorities. This requires concurrent challenge of the racist and patriarchal structures that continue to obscure the sexual and reproductive health needs of racially minoritized and marginalized women and non-binary people.

Objectives: UK Black African/Black Caribbean women remain disproportionately affected by HIV. Although oral pre-exposure prophylaxis (PrEP) could offer them an effective HIV prevention method, uptake remains limited. This study examined barriers and facilitators to PrEP awareness and candidacy perceptions for Black African/Black Caribbean women to help inform PrEP programmes and service development., Methods: Using purposive sampling through community organisations, 32 in-depth, semi-structured interviews were conducted with Black African/Black Caribbean women living in London and Glasgow between June and August 2018. Participants (aged 19-63) included women of varied HIV statuses to explore perceptions of sexual risk and safer sex, sexual health knowledge and PrEP attitudes. A thematic analysis guided by the Social Ecological Model was used to explore how PrEP perceptions intersected with wider safer sex understandings and practices., Results: Four key levels of influence shaping safer sex notions and PrEP candidacy perceptions emerged: personal, interpersonal, perceived environment and policy. PrEP-specific knowledge was low and some expressed distrust in PrEP. Many women were enthusiastic about PrEP for others but did not situate PrEP within their own safer sex understandings, sometimes due to difficulty assessing their own HIV risk. Many felt that PrEP could undermine intimacy in their relationships by disrupting the shared responsibility implicit within other HIV prevention methods. Women described extensive interpersonal networks that supported their sexual health knowledge and shaped their interactions with health services, though these networks were influenced by prevailing community stigmas., Conclusions: Difficulty situating PrEP within existing safer sex beliefs contributes to limited perceptions of personal PrEP candidacy. To increase PrEP uptake in UK Black African/Black Caribbean women, interventions will need to enable women to advance their knowledge of PrEP within the broader context of their sexual health and relationships. PrEP service models will need to include trusted 'non-sexual health-specific' community services such as general practice., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Competing Interests: Competing interests: None declared.

A new imaging technology has emerged that uses carbon nanotubes (CNT) as the electron emitter (cathode) for the X-ray tube. Since the performance of the CNT cathode is controlled by simple voltage manipulation, CNT-enabled X-ray sources are ideal for the repetitive imaging steps needed to capture three-dimensional information. As such, they have allowed the development of a gated micro-computed tomography (CT) scanner for small animal research as well as stationary tomosynthesis, an experimental technology for large field-of-view human imaging. The small animal CT can acquire images at specific points in the respiratory and cardiac cycles. Longitudinal imaging therefore becomes possible and has been applied to many research questions, ranging from tumor response to the noninvasive assessment of cardiac output. Digital tomosynthesis (DT) is a low-dose and low-cost human imaging tool that captures some depth information. Known as three-dimensional mammography, DT is now used clinically for breast imaging. However, the resolution of currently-approved DT is limited by the need to swing the X-ray source through space to collect a series of projection views. An array of fixed and distributed CNT-enabled sources provides the solution and has been used to construct stationary DT devices for breast, lung, and dental imaging. To date, over 100 patients have been imaged on Institutional Review Board-approved study protocols. Early experience is promising, showing an excellent conspicuity of soft-tissue features, while also highlighting technical and post-acquisition processing limitations that are guiding continued research and development. Additionally, CNT-enabled sources are being tested in miniature X-ray tubes that are capable of generating adequate photon energies and tube currents for clinical imaging. Although there are many potential applications for these small field-of-view devices, initial experience has been with an X-ray source that can be inserted into the mouth for dental imaging. Conceived less than 20 years ago, CNT-enabled X-ray sources are now being manufactured on a commercial scale and are powering both research tools and experimental human imaging devices. WIREs Nanomed Nanobiotechnol 2018, 10:e1475. doi: 10.1002/wnan.1475 This article is categorized under: Diagnostic Tools > Diagnostic Nanodevices Diagnostic Tools > In Vivo Nanodiagnostics and Imaging., (© 2017 Wiley Periodicals, Inc.)

Purpose: The aim of this study was to characterize a new generation stationary digital breast tomosynthesis system with higher tube flux and increased angular span over a first generation system., Methods: The linear CNT x-ray source was designed, built, and evaluated to determine its performance parameters. The second generation system was then constructed using the CNT x-ray source and a Hologic gantry. Upon construction, test objects and phantoms were used to characterize system resolution as measured by the modulation transfer function (MTF), and artifact spread function (ASF)., Results: The results indicated that the linear CNT x-ray source was capable of stable operation at a tube potential of 49 kVp, and measured focal spot sizes showed source-to-source consistency with a nominal focal spot size of 1.1 mm. After construction, the second generation (Gen 2) system exhibited entrance surface air kerma rates two times greater the previous s-DBT system. System in-plane resolution as measured by the MTF is 7.7 cycles/mm, compared to 6.7 cycles/mm for the Gen 1 system. As expected, an increase in the z-axis depth resolution was observed, with a decrease in the ASF from 4.30 mm to 2.35 mm moving from the Gen 1 system to the Gen 2 system as result of an increased angular span., Conclusions: The results indicate that the Gen 2 stationary digital breast tomosynthesis system, which has a larger angular span, increased entrance surface air kerma, and faster image acquisition time over the Gen 1 s-DBT system, results in higher resolution images. With the detector operating at full resolution, the Gen 2 s-DBT system can achieve an in-plane resolution of 7.7 cycles per mm, which is better than the current commercial DBT systems today, and may potentially result in better patient diagnosis., (© 2017 American Association of Physicists in Medicine.)

Scatter radiation severely degrades the image quality. Measurement-based scatter correction methods sample the scatter signal at sparsely distributed points, from which the scatter profile is estimated and deterministically removed from the projection image. The estimation of the scatter profile is generally done through a spline interpolation and the resulting scatter profile is quite smooth. Consequently, the noise is intact and the signal-to-noise ratio is reduced in the projection image after scatter correction, leading to image artifacts and increased noise in the reconstruction images. We propose a simple and effective method, referred to as filtered scatter-to-primary ratio ([Formula: see text]-SPR) estimation, to estimate the scatter profile using the sparsely sampled scatter signal. Using the primary sampling device and the stationary digital tomosynthesis systems previously developed in our lab, we evaluated and compared the [Formula: see text]-SPR method in comparison with existing methods in terms of contrast ratio, signal difference-to-noise ratio, and modulation transfer function. A significant improvement in image quality is observed in both the projection and the reconstruction images using the proposed method.

Rational and Objectives: The objective of this study was to compare the stationary digital breast tomosynthesis (s-DBT) system to a conventional mammography system in a study of breast specimens. Radiologist evaluation of image quality was assessed in a reader study. This study represents the first human tissue imaging with the novel carbon nanotube-based s-DBT device., Materials and Methods: Thirty-nine patients, with known breast lesions (Breast Imaging Reporting and Data System 4 or 5) by conventional mammography and scheduled for needle localization biopsy, were recruited under an institutional review board-approved protocol. Specimen images were obtained using a two-dimensional (2D) mammography system with a ×1.8 magnification factor and an s-DBT system without a high magnification factor. A reader study was performed with four breast fellowship-trained radiologists over two separate sessions. Malignancy scores were recorded for both masses and microcalcifications (MCs). Reader preference between the two modalities for MCs, masses, and surgical margins was recorded., Results: The s-DBT system was found to be comparable to magnified 2D mammography for malignancy diagnosis. Readers preferred magnified 2D mammography for MC visualization (P < .05). However, readers trended toward a preference for s-DBT with respect to masses and surgical margin assessment., Conclusions: Here, we report on the first human data acquired using a stationary digital breast tomosynthesis system. The novel s-DBT system was found to be comparable to magnified 2D mammography imaging for malignancy diagnosis. Given the trend of preference for s-DBT over 2D mammography for both mass visibility and margin assessment, s-DBT could be a viable alternative to magnified 2D mammography for imaging breast specimens., (Copyright © 2014 AUR. Published by Elsevier Inc. All rights reserved.)