949 research outputs found
Diffraction-limited plenoptic imaging with correlated light
Traditional optical imaging faces an unavoidable trade-off between resolution
and depth of field (DOF). To increase resolution, high numerical apertures (NA)
are needed, but the associated large angular uncertainty results in a limited
range of depths that can be put in sharp focus. Plenoptic imaging was
introduced a few years ago to remedy this trade off. To this aim, plenoptic
imaging reconstructs the path of light rays from the lens to the sensor.
However, the improvement offered by standard plenoptic imaging is practical and
not fundamental: the increased DOF leads to a proportional reduction of the
resolution well above the diffraction limit imposed by the lens NA. In this
paper, we demonstrate that correlation measurements enable pushing plenoptic
imaging to its fundamental limits of both resolution and DOF. Namely, we
demonstrate to maintain the imaging resolution at the diffraction limit while
increasing the depth of field by a factor of 7. Our results represent the
theoretical and experimental basis for the effective development of the
promising applications of plenoptic imaging.Comment: 10 pages, 10 figure
Impact of ART Use on Labour Force Participation among PLWHA Using ART in Southern Highlands HIV/AIDS Program in Tanzania
This is the retrospective cohort study which was conducted to analyse the impact of ART on labour force participation by 2829 PLWHA using ART at in Tanzania from 2005 to 2011. Quantitative method of research was applied and review of patients’ record was used to collect data. The results revealed that 92.4% of PLWHA registered on ART belong to working age group i.e. 15 – 65 years old (t-statistical value = 4.9 and p - value = 0.0002). There were 92.0% PLWHA who were able to work before ART, but labour force increased to 99.5% after PLWHA initiated on ART (correlation coefficient, r = 0.999, p-value < 0.001). The researcher concluded that majority of PLWHA using ART belongs to the working age group, and ART increases PLWHA labour force participation .The researcher therefore recommended that ART is worth continuing on with the universal population coverage. The study has some limitations as it assessed only one benefits of ART that is labour force participation of PLWHA. Key words: PLWHA, Antiretroviral therapy, labour force participation, resource limited settin
Antigenic rapid test for SARS-CoV2 screening of individuals newly admitted to detention facilities : sensibility in an asymptomatic cohort
Background: Since the start of the Sars-CoV-2 pandemic, attention was called on the potential risk of COVID-19 outbreaks occurring inside prisons. In detention facilities, timely and accurate diagnosis is essential for allowing case isolation and contact tracing to avoid the spread of the infection. Until recently, reverse-transcriptase polymerase chain reaction (rt-PCR) was the recommended method to diagnose SARS-CoV-2 infection. However, antigen-detecting rapid diagnostic tests (ag-RDT) have emerged as point-of-care testing techniques. Objectives: Here, we evaluate the use of ag-RDT for screening of individuals newly admitted to San Vittore prison (SV), a pre-trial prison, in Milan (Lombardy region, Italy), during the second SARS-CoV2 epidemic peak. Methods: During the period 1 October-31 December 2020, ag-RDT and rt-PCR were performed individuals newly admitted to SV. Results: Among 504 detained individuals tested, 21 (4,2%) resulted positive to rt-PCR. Of these, 10 had tested negative with ag-RDT and 11 had concordant results. Rt-PCR cycle threshold (CT) values were above 35 for the individuals with ag-RDT negative test, therefore the cases missed by the ag-RDT are unlikely to transmit disease. For all the individuals with ag-RDT positive results, CT values were below or equal to 27. In our study population, ag-RDT sensitivity was 52.4% (29.8%-74.3%), positive predictive value (PPV) was 100% and negative predictive value was 98.0% (96.8%-98.7%). Discussion: Our study showed that ag-RDT is a promising and useful component of serial testing strategies in prison settings to perform SARS-CoV2 screening at admission based to its high PPV, ease of use, lower costs and resource needs
The Role of Fibroblasts in Skin Homeostasis and Repair
Fibroblasts are typical mesenchymal cells widely distributed throughout the human body where they (1) synthesise and maintain the extracellular matrix, ensuring the structural role of soft connective tissues; (2) secrete cytokines and growth factors; (3) communicate with each other and with other cell types, acting as signalling source for stem cell niches; and (4) are involved in tissue remodelling, wound healing, fibrosis, and cancer. This review focuses on the developmental heterogeneity of dermal fibroblasts, on their ability to sense changes in biomechanical properties of the surrounding extracellular matrix, and on their role in aging, in skin repair, in pathologic conditions and in tumour development. Moreover, we describe the use of fibroblasts in different models (e.g., in vivo animal models and in vitro systems from 2D to 6D cultures) for tissue bioengineering and the informative potential of high-throughput assays for the study of fibroblasts under different disease contexts for personalized healthcare and regenerative medicine applications
A Frequency Tripler Using a Subharmonic Mixer and Fundamental Cancellation
A new odd-order frequency multiplier topology is demonstrated in this work that uses a subharmonic mixer to realize a frequency tripler. A feedforward circuit is used for fundamental cancellation at the output and eliminates the need for filtering structures. For demonstrative purposes, and to validate the concept, a 1-3-GHz proof-of-concept frequency tripler circuit was fabricated. The tripler circuit achieved a measured output fundamental suppression of up to 30 dB below the third harmonic and a conversion gain of up to 3 dB. The circuit was implemented in CMOS 0.18-mu m technology and the chip area was 0.8 mm(2) including bonding pads
Understanding care relationships in diabetes practice. A psychodynamic interview-based exploratory study
ObjectiveTo explore the subjective experience of physicians working in diabetic settings about their care relationships in order to find some unique clues contributing to physician professional health and capacity to manage patients' adherence.Research design and methodsAn interview-based exploratory study has been carried out involving 18 physicians (77.8% female) with at least 3 years of clinical practice in diabetes care. In-depth interviews about the emotional experience with patients with diabetes were conducted and audio recorded. Interviews transcripts were analyzed through a computer-based text analysis which allowed the identification of thematic domains (Cluster Analysis) and latent factors (Correspondence Analysis) viewed through a psychodynamic and constructivist lens.ResultsSix thematic domains emerged respectively referring to: Concern (8.43%), Control (14.42%), Ambivalence (22.08%), Devotion (22.49%), Guilt (19.29%) and Strive for Achievement (13.30%). Moreover, three latent dimensions were taken into account, which explained 69.20% of data variance: Affect Repression (28.50%), Tendency to Repair (22.70%) and Anxiety Pattern (18.00%).ConclusionsOverall, the results of the present study confirm the challenging nature of diabetes care. In particular, physicians ongoing effort to restore patients' psychological integrity in chronic condition constitute the most novel finding above all. In this regard, the need for emotional labor in physicians' education and training is suggested in order to both prevent burnout symptoms (e.g. depersonalization) and promote shared decision making in care relationships. However, findings should be treated as preliminary given the convenience nature of the sample and its reduced size
Design methodology and comparison of rectifiers for UHF-band RFIDs
Rectifiers are important energy converters and henceforth crucial building blocks for RFID applications. In the first half of the work, we have presented a design methodology for matching the rectifier input impedance with the antenna to maximize the rectifier power conversion efficiency. The proposed design approach uses the fundamental transconductance (Gm(1)) analysis to estimate the rectifier input impedance. In the second half, a comparison between various possible single-stage rectifier topologies implemented in a CMOS 0.18 mu m technology operating at UHF-band is presented. Using voltage conversion efficiency as the FOM, the optimum rectifier topology for RFID application is determined
Severe male factor in in vitro fertilization: definition, prevalence, and treatment. An update
Infertility affects 10%-15% of couples worldwide. Of all infertility cases, 20%-70% are due to male factors. In the past, men with severe male factor (SMF) were considered sterile. Nevertheless, the development of intracytoplasmic sperm injection (ICSI) drastically modified this scenario. The advances in assisted reproductive technology (ART), specifically regarding surgical sperm retrieval procedures, allowed the efficacious treatment of these conditions. Yet, before undergoing ICSI, male factor infertility requires careful evaluation of clinical and lifestyle behavior together with medical treatment. Epidemiologically speaking, women whose male partner is azoospermic tend to be younger and with a better ovarian reserve. These couples, in fact, are proposed ART earlier in their life, and for this reason, their ovarian response after stimulation is generally good. Furthermore, in younger couples, azoospermia can be partially compensated by the efficient ovarian response, resulting in an acceptable fertility rate following in vitro fertilization (IVF) techniques. Conversely, when azoospermia is associated with a reduced ovarian reserve and/or advanced maternal age, the treatment becomes more challenging, with a consequent reduction in IVF outcomes. Nonetheless, azoospermia seems to impair neither the euploidy rate at the blastocyst stage nor the implantation of euploid blastocysts. Based on the current knowledge, the assessment of male infertility factors should involve: (1) evaluation - to diagnose and quantify seminologic alterations; (2) potentiality - to determine the real possibilities to improve sperm parameters and/or retrieve spermatozoa; (3) time - to consider the available "treatment window", based on maternal age and ovarian reserve. This review represents an update of the definition, prevalence, causes, and treatment of SMF in a modern ART clinic
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