277 research outputs found

    Clusters and networks as enablers of product and process innovation

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    One of the strategies adopted in the Philippines to facilitate a more consistent supply of good quality vegetables from smallholder farmers is the clustering approach, whereby a small group or cluster of smallholder farmers is organized to deliver a pre-determined amount of produce to a focal customer (CRS-Philippines, 2007). Developed from the CIAT Territorial Approach, the CRS Eight Step Clustering Approach for Agro-enterprise Development employs a participatory action learning process, where the cluster members proactively plan their production to meet the specifc quality and delivery requirements of their focal customer. The clustering approach is a strategy which allows smallholder farmers to access higher value chains. Evidence is provided to demonstrate how several of the clusters facilitated have utilised the skills and knowledge acquired in servicing their focal customer to develop new products for new markets, to adopt alternative low cost systems of production to reduce their reliance on external inputs, to reduce postharvest losses and product deterioration through improved packaging, to improve access to low cost community-based loans and to take advantage of local and national government grants that provide production inputs and support the development of community-based infrastructure projects

    Plasma lensing of a laser wakefield accelerated electron bunch

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    We report on the first all-optical demonstration of plasma lensing using laser wakefield accelerated elec-trons in a two-stage setup. The LWFA electron bunch was focused by a second plasma stage without any ex-ternal fields applied..

    HIV status alters disease severity and immune cell responses in Beta variant SARS-CoV-2 infection wave

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    There are conflicting reports on the effects of HIV on COVID-19. Here, we analyzed disease severity and immune cell changes during and after SARS-CoV-2 infection in 236 participants from South Africa, of which 39% were people living with HIV (PLWH), during the first and second (Beta dominated) infection waves. The second wave had more PLWH requiring supplemental oxygen relative to HIV-negative participants. Higher disease severity was associated with low CD4 T cell counts and higher neutrophil to lymphocyte ratios (NLR). Yet, CD4 counts recovered and NLR stabilized after SARS-CoV-2 clearance in wave 2 infected PLWH, arguing for an interaction between SARS-CoV-2 and HIV infection leading to low CD4 and high NLR. The first infection wave, where severity in HIV negative and PLWH was similar, still showed some HIV modulation of SARS-CoV-2 immune responses. Therefore, HIV infection can synergize with the SARS-CoV-2 variant to change COVID-19 outcomes

    Dual strain mechanisms in a lead-free morphotropic phase boundary ferroelectric

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    Electromechanical properties such as d33 and strain are significantly enhanced at morphotropic phase boundaries (MPBs) between two or more different crystal structures. Many actuators, sensors and MEMS devices are therefore systems with MPBs, usually between polar phases in lead (Pb)-based ferroelectric ceramics. In the search for Pb-free alternatives, systems with MPBs between polar and non-polar phases have recently been theorized as having great promise. While such an MPB was identified in rare-earth (RE) modified bismuth ferrite (BFO) thin films, synthesis challenges have prevented its realization in ceramics. Overcoming these, we demonstrate a comparable electromechanical response to Pb-based materials at the polar-to-non-polar MPB in Sm modified BFO. This arises from ‘dual’ strain mechanisms: ferroelectric/ferroelastic switching and a previously unreported electric-field induced transition of an anti-polar intermediate phase. We show that intermediate phases play an important role in the macroscopic strain response, and may have potential to enhance electromechanical properties at polar-to-non-polar MPBs

    Ionizing radiation modulates human macrophages towards a pro-inflammatory phenotype preserving their pro-invasive and pro-angiogenic capacities

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    In order to improve the efficacy of conventional radiotherapy, attention has been paid to immune cells, which not only modulate cancer cell response to therapy but are also highly recruited to tumours after irradiation. Particularly, the effect of ionizing radiation on macrophages, using therapeutically relevant doses, is not well understood. To evaluate how radiotherapy affects macrophage behaviour and macrophage-mediated cancer cell activity, human monocyte derived-macrophages were subjected, for a week, to cumulative ionizing radiation doses, as used during cancer treatment (2Gy/fraction/day). Irradiated macrophages remained viable and metabolically active, despite DNA damage. NF-kappaB transcription activation and increased Bcl-xL expression evidenced the promotion of pro-survival activity. A significant increase of pro-inflammatory macrophage markers CD80, CD86 and HLA-DR, but not CCR7, TNF and IL1B was observed after 10Gy cumulative doses, while anti-inflammatory markers CD163, MRC1, VCAN and IL-10 expression decreased, suggesting the modulation towards a more proinflammatory phenotype. Moreover, ionizing radiation induced macrophage morphological alterations and increased their phagocytic rate, without affecting matrix metalloproteases (MMP)2 and MMP9 activity. Importantly, irradiated macrophages promoted cancer cell-invasion and cancer cell-induced angiogenesis. Our work highlights macrophage ability to sustain cancer cell activities as a major concern that needs to be addressed to improve radiotherapy efficacy

    Intensified concurrent chemoradiotherapy with 5-fluorouracil and irinotecan as neoadjuvant treatment in patients with locally advanced rectal cancer

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    This study aimed to evaluate the feasibility and efficacy of neoadjuvant chemoradiotherapy intensified with irinotecan in patients with locally advanced rectal cancer. Eligible patients had nonmetastatic disease at a locally advanced stage that made R0 resection and sphincter preservation uncertain. They received preoperative radiation over 6 weeks to 45 Gy and boost of 5.4 Gy and concurrent continuous infusion 5-fluorouracil 250 mg m−2 day−1 and weekly irinotecan 40 mg m−2. In all, 37 patients entered the study. T stage at baseline as determined by ultrasound was T2/T3/T4 in 2/19/16 patients; 31 patients had lymph node involvement. The predominant toxicity was diarrhoea (grade 3/4 in 10/2 patients). Haematologic toxicity and surgical complications were moderate. Among 36 patients undergoing surgery, 32 (89%) had R0 resection and 23 (64%) sphincter preservation. Pathologic complete response (pCR) was achieved in eight (22%) of 36 patients, and 10 patients (28%) had only microscopic residual disease. At 4 years, overall survival was 66%, disease-free survival 73%, local relapse rate 7%, and distant failure rate 24%. Extent of resection and postoperative nodal status were significant predictors of overall and disease-free survival. Intensified neoadjuvant chemoradiotherapy with irinotecan can be safely administered and results in a high pCR rate

    The effect on the small bowel of 5-FU and oxaliplatin in combination with radiation using a microcolony survival assay

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    <p>Abstract</p> <p>Background</p> <p>In locally advanced rectal cancer, 5-Fluorouracil (5-FU)-based chemoradiation is the standard treatment. The main acute toxicity of this treatment is enteritis. Due to its potential radiosensitizing properties, oxaliplatin has recently been incorporated in many clinical chemoradiation protocols. The aim of this study was to investigate to what extent 5-FU and oxaliplatin influence the radiation (RT) induced small bowel mucosal damage when given in conjunction with single or split dose RT.</p> <p>Methods</p> <p>Immune competent balb-c mice were treated with varying doses of 5-FU, oxaliplatin (given intraperitoneally) and total body RT, alone or in different combinations in a series of experiments. The small bowel damage was studied by a microcolony survival assay. The treatment effect was evaluated using the inverse of the slope (D<sub>0</sub>) of the exponential part of the dose-response curve.</p> <p>Results</p> <p>In two separate experiments the dose-response relations were determined for single doses of RT alone, yielding D<sub>0 </sub>values of 2.79 Gy (95% CI: 2.65 - 2.95) and 2.98 Gy (2.66 - 3.39), for doses in the intervals of 5-17 Gy and 5-10 Gy, respectively. Equitoxic low doses (IC5) of the two drugs in combination with RT caused a decrease in jejunal crypt count with significantly lower D<sub>0</sub>: 2.30 Gy (2.10 - 2.56) for RT+5-FU and 2.27 Gy (2.08 - 2.49) for RT+oxaliplatin. Adding both drugs to RT did not further decrease D<sub>0</sub>: 2.28 Gy (1.97 - 2.71) for RT+5-FU+oxaliplatin. A clearly higher crypt survival was noted for split course radiation (3 × 2.5 Gy) compared to a single fraction of 7.5 Gy. The same difference was seen when 5-FU and/or oxaliplatin were added.</p> <p>Conclusion</p> <p>Combining 5-FU or oxaliplatin with RT lead to an increase in mucosal damage as compared to RT alone in our experimental setting. No additional reduction of jejunal crypt counts was noted when both drugs were combined with single dose RT. The higher crypt survival with split dose radiation indicates a substantial recovery between radiation fractions. This mucosal-sparing effect achieved by fractionation was maintained also when chemotherapy was added.</p

    CPT-11 and concomitant hyperfractionated accelerated radiotherapy induce efficient local control in rectal cancer patients: results from a phase II

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    Patients with rectal cancer are at high risk of disease recurrence despite neoadjuvant radiochemotherapy with 5-Fluorouracil (5FU), a regimen that is now widely applied. In order to develop a regimen with increased antitumour activity, we previously established the recommended dose of neoadjuvant CPT-11 (three times weekly 90 mg m−2) concomitant to hyperfractionated accelerated radiotherapy (HART) followed by surgery within 1 week. Thirty-three patients (20 men) with a locally advanced adenocarcinoma of the rectum were enrolled in this prospective phase II trial (1 cT2, 29 cT3, 3 cT4 and 21 cN+). Median age was 60 years (range 43–75 years). All patients received all three injections of CPT-11 and all but two patients completed radiotherapy as planned. Surgery with total mesorectal excision (TME) was performed within 1 week (range 2–15 days). The preoperative chemoradiotherapy was overall well tolerated, 24% of the patients experienced grade 3 diarrhoea that was easily manageable. At a median follow-up of 2 years no local recurrence occurred, however, nine patients developed distant metastases. The 2-year disease-free survival was 66% (95% confidence interval 0.48–0.83). Neoadjuvant CPT-11 and HART allow for excellent local control; however, distant relapse remains a concern in this patient population
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