A simulation-based analysis of photovoltaic thermal hybrid solar collectors with a new TRNSYS type model

Nowadays buildings are responsible of 36% of CO2emissions and space heating and cooling alone accounts for 40% of the final energy consumption at European level. In this context, solar-assisted systems represent an important solution to support the decarbonisation pathways in residential sector. In this work, a novel lumped parameter simulation model for photovoltaic thermal hybrid solar collectors developed by Authors as a type of Transient System Simulation (TRNSYS) software is used to carry out computer simulations in different climatic conditions. The model is based on the electrical analogy method to solve the transient heat transfer problem and considers the effect of the thermal capacitances of the elements composing the photovoltaic thermal collector. The simulation tool was also validated with the experimental data in terms of both electrical and thermal power. In this work, a simulation-based analysis is carried out considering three climatic zones in order to evaluate the thermal performance of photovoltaic thermal hybrid solar collectors under different operating conditions

Lentiviral vector-mediated gene transfer in T cells from Wiskott-Aldrich syndrome patients leads to functional correction

Wiskott–Aldrich syndrome (WAS) is an X-linked primary immunodeficiency with a median survival below the age of 20 due to infections, severe hemorrhage, and lymphomas. Transplantation of hematopoietic stem cells from HLA-identical sibling donors is a resolutive treatment, but is available for a minority of patients. Transplantation of genetically corrected autologous hematopoietic stem cells or T cells could represent an alternative treatment applicable to all patients. We investigated whether WAS gene transfer with MMLV-based oncoretroviral and HIV-based lentiviral vectors could restore normal functions of patients' T cells. T cells transduced either with lentiviral vectors expressing the WAS protein (WASP) from the ubiquitous PGK promoter or the tissue-specific WASP promoter or with an oncoretroviral vector expressing WASP from the LTR, reached normal levels of WASP with correction of functional defects, including proliferation, IL-2 production, and lipid raft upregulation. Lentiviral vectors transduced T cells from WAS patients at higher rates, compared to oncoretroviral vectors, and efficiently transduced both activated and naive WAS T cells. Furthermore, a selective growth advantage of T cells corrected with the lentiviral vectors was demonstrated. The observation that lentiviral vector-mediated gene transfer results in correction of T cell defects in vitro supports their application for gene therapy in WAS patients

IL-3 or IL-7 Increases ex Vivo Gene Transfer Efficiency in ADA-SCID BM CD34 + Cells while Maintaining in Vivo Lymphoid Potential

To improve maintenance and gene transfer of human lymphoid progenitors for clinical use in gene therapy of adenosine deaminase (ADA)-deficient SCID we investigated several gene transfer protocols using various stem cell-enriched sources. The lymphoid differentiation potential was measured by an in vitro clonal assay for B/NK cells and in the in vivo SCID-hu mouse model. Ex vivo culture with the cytokines TPO, FLT3-ligand, and SCF (T/F/S) plus IL-3 or IL-7 substantially increased the yield of transduced bone marrow (BM) CD34+ cells purified from ADA-SCID patients or healthy donors, compared to T/F/S alone. Moreover, the use of IL-3 or IL-7 significantly improved the maintenance of in vitro B cell progenitors from ADA-SCID BM cells and allowed the efficient transduction of B and NK cell progenitors. Under these optimized conditions transduced CD34+ cells were efficiently engrafted into SCID-hu mice and gave rise to B and T cell progeny, demonstrating the maintenance of in vivo lymphoid reconstitution capacity. The protocol based on the T/F/S + IL-3 combination was included in a gene therapy clinical trial for ADA-SCID, resulting in long-term engraftment of stem/progenitor cells. Remarkably, gene-corrected BM CD34+ cells obtained from one patient 4 and 11 months after gene therapy were capable of repopulating the lymphoid compartment of SCID-hu hosts

Molecular purging of multiple myeloma cells by ex-vivo culture and retroviral transduction of mobilized-blood CD34+ cells

<p>Abstract</p> <p>Background</p> <p>Tumor cell contamination of the apheresis in multiple myeloma is likely to affect disease-free and overall survival after autografting.</p> <p>Objective</p> <p>To purge myeloma aphereses from tumor contaminants with a novel culture-based purging method.</p> <p>Methods</p> <p>We cultured myeloma-positive CD34⁺PB samples in conditions that retained multipotency of hematopoietic stem cells, but were unfavourable to survival of plasma cells. Moreover, we exploited the resistance of myeloma plasma cells to retroviral transduction by targeting the hematopoietic CD34⁺cell population with a retroviral vector carrying a selectable marker (the truncated form of the human receptor for nerve growth factor, ΔNGFR). We performed therefore a further myeloma purging step by selecting the transduced cells at the end of the culture.</p> <p>Results</p> <p>Overall recovery of CD34⁺cells after culture was 128.5%; ΔNGFR transduction rate was 28.8% for CD34⁺cells and 0% for CD138-selected primary myeloma cells, respectively. Recovery of CD34⁺cells after ΔNGFR selection was 22.3%. By patient-specific Ig-gene rearrangements, we assessed a decrease of 0.7–1.4 logs in tumor load after the CD34⁺cell selection, and up to 2.3 logs after culture and ΔNGFR selection.</p> <p>Conclusion</p> <p>We conclude that <it>ex-vivo </it>culture and retroviral-mediated transduction of myeloma leukaphereses provide an efficient tumor cell purging.</p

The use of a P. falciparum specific coiled-coil domain to construct a self-assembling protein nanoparticle vaccine to prevent malaria.

The parasitic disease malaria remains a major global public health concern and no truly effective vaccine exists. One approach to the development of a malaria vaccine is to target the asexual blood stage that results in clinical symptoms. Most attempts have failed. New antigens such as P27A and P27 have emerged as potential new vaccine candidates. Multiple studies have demonstrated that antigens are more immunogenic and are better correlated with protection when presented on particulate delivery systems. One such particulate delivery system is the self-assembling protein nanoparticle (SAPN) that relies on coiled-coil domains of proteins to form stable nanoparticles. In the past we have used de novo designed amino acid domains to drive the formation of the coiled-coil scaffolds which present the antigenic epitopes on the particle surface. Here we use naturally occurring domains found in the tex1 protein to form the coiled-coil scaffolding of the nanoparticle. Thus, by engineering P27A and a new extended form of the coiled-coil domain P27 onto the N and C terminus of the SAPN protein monomer we have developed a particulate delivery system that effectively displays both antigens on a single particle that uses malaria tex1 sequences to form the nanoparticle scaffold. These particles are immunogenic in a murine model and induce immune responses similar to the ones observed in seropositive individuals in malaria endemic regions. We demonstrate that our P27/P27A-SAPNs induce an immune response akin to the one in seropositive individuals in Burkina Faso. Since P27 is highly conserved among different Plasmodium species, these novel SAPNs may even provide cross-protection between Plasmodium falciparum and Plasmodium vivax the two major human malaria pathogens. As the SAPNs are also easy to manufacture and store they can be delivered to the population in need without complication thus providing a low cost malaria vaccine

Semen molecular and cellular features: these parameters can reliably predict subsequent ART outcome in a goat model

Currently, the assessment of sperm function in a raw or processed semen sample is not able to reliably predict sperm ability to withstand freezing and thawing procedures and in vivo fertility and/or assisted reproductive biotechnologies (ART) outcome. The aim of the present study was to investigate which parameters among a battery of analyses could predict subsequent spermatozoa in vitro fertilization ability and hence blastocyst output in a goat model. Ejaculates were obtained by artificial vagina from 3 adult goats (Capra hircus) aged 2 years (A, B and C). In order to assess the predictive value of viability, computer assisted sperm analyzer (CASA) motility parameters and ATP intracellular concentration before and after thawing and of DNA integrity after thawing on subsequent embryo output after an in vitro fertility test, a logistic regression analysis was used. Individual differences in semen parameters were evident for semen viability after thawing and DNA integrity. Results of IVF test showed that spermatozoa collected from A and B lead to higher cleavage rates (0 < 0.01) and blastocysts output (p < 0.05) compared with C. Logistic regression analysis model explained a deviance of 72% (p < 0.0001), directly related with the mean percentage of rapid spermatozoa in fresh semen (p < 0.01), semen viability after thawing (p < 0.01), and with two of the three comet parameters considered, i.e tail DNA percentage and comet length (p < 0.0001). DNA integrity alone had a high predictive value on IVF outcome with frozen/thawed semen (deviance explained: 57%). The model proposed here represents one of the many possible ways to explain differences found in embryo output following IVF with different semen donors and may represent a useful tool to select the most suitable donors for semen cryopreservation

A dynamic analysis of a SAGSHP system coupled to solar thermal collectors and photovoltaic-thermal panels under different climate conditions

The use of multi-source energy systems is a promising technical solution for the reduction of greenhouse gases emissions and, at the meantime, for enhancing the exploitation of renewable energy sources. The present paper analyses a Solar Assisted Ground Source Heat Pump system and tries to fill the gap in the literature, where a direct comparison between the consolidated solar thermal technology and the emerging and widely discussed photovoltaic thermal technology is missing. Indeed, the two different devices for the exploitation of solar energy have been analysed through dynamic simulations carried out in TRNSYS environment. Through this approach, it is possible to investigate and predict in detail the thermal and electrical behaviour of the energy system, composed by a water-to-water heat pump, which withdraws from two thermal reservoirs that are connected to a solar loop, composed either of solar thermal collectors or of photovoltaic thermal panels and to a ground loop. The heat pump is used to provide space cooling and space heating to a residential building, through fan coil terminal units or radiant floor system. Furthermore, the heat pump system assists the solar field in the production of domestic hot water. This study looks at the development of a flexible system able to work in different operating conditions. The model's boundary conditions can be changed for simulating a variety of case studies as the weather condition, the building load and the domestic hot water profile can be easily changed, together with specific components’ parameters. The control strategy makes it possible to vary the setpoint temperatures for simulating different operating conditions and management choices. In this way, the user can easily adapt the model functions to a specific plant system. The operating conditions of the two systems layouts have been compared and the energy performances evaluated for three case studies characterised by the weather conditions of the European cities of Berlin (mild-cold climate), Venice (mild climate) and Barcelona (mild-warm climate), and the corresponding thermal load profile of a two-storey building with a useful floor area of 170 m2. The study shows the possibility to directly exploit the solar energy for the domestic hot water production and as a heat source for the heat pump. The results from the comparison between the two systems’ configurations, with photovoltaic thermal panels and with solar thermal collectors, prove that there is the possibility to obtain a relevant improvement in the efficiency of the heat pump using photovoltaic thermal panels. The investigated multi-source energy system, moreover, allows an optimal employment of the available renewable heat sources and could easily be applied to case studies characterized by different boundary conditions

A simulation-based analysis of photovoltaic thermal hybrid solar collectors with a new TRNSYS type model

Nowadays buildings are responsible of 36% of CO2emissions and space heating and cooling alone accounts for 40% of the final energy consumption at European level. In this context, solar-assisted systems represent an important solution to support the decarbonisation pathways in residential sector. In this work, a novel lumped parameter simulation model for photovoltaic thermal hybrid solar collectors developed by Authors as a type of Transient System Simulation (TRNSYS) software is used to carry out computer simulations in different climatic conditions. The model is based on the electrical analogy method to solve the transient heat transfer problem and considers the effect of the thermal capacitances of the elements composing the photovoltaic thermal collector. The simulation tool was also validated with the experimental data in terms of both electrical and thermal power. In this work, a simulation-based analysis is carried out considering three climatic zones in order to evaluate the thermal performance of photovoltaic thermal hybrid solar collectors under different operating conditions