278 research outputs found
Luminescent solar concentrators: boosted optical efficiency by polymer dielectric mirrors
We report on the optical efficiency enhancement of luminescent solar concentrators based on a push\u2013
pull fluorophore realized using high dielectric contrast polymer distributed Bragg reflectors as back
mirrors. The Bragg stacks are obtained by alternating layers of cellulose acetate and thin films of a new
stable and solution processable hydrated titania\u2013poly(vinyl alcohol) nanocomposite (HyTiPVA) with a
refractive index greater than 1.9 over a broad spectral range. The results obtained with these systems are
compared with enhancements provided by standard Bragg reflectors made of commercial polymers. We
demonstrate that the application of the Bragg stacks with photonic band-gap tuned to the low energy
side of the dye emission spectrum induces a 10% enhancement of optical efficiency. This enhancement
is the result of a photon recycling mechanism and is retained even in a scaled-up device where the
Bragg mirrors are used in a mosaic configuratio
Genome characteristics of facultatively symbiotic Frankia sp. strains reflect host range and host plant biogeography
Soil bacteria that also form mutualistic symbioses in plants encounter two major levels of selection. One occurs during adaptation to and survival in soil, and the other occurs in concert with host plant speciation and adaptation. Actinobacteria from the genus Frankia are facultative symbionts that form N2-fixing root nodules on diverse and globally distributed angiosperms in the “actinorhizal” symbioses. Three closely related clades of Frankia sp. strains are recognized; members of each clade infect a subset of plants from among eight angiosperm families. We sequenced the genomes from three strains; their sizes varied from 5.43 Mbp for a narrow host range strain (Frankia sp. strain HFPCcI3) to 7.50 Mbp for a medium host range strain (Frankia alni strain ACN14a) to 9.04 Mbp for a broad host range strain (Frankia sp. strain EAN1pec.) This size divergence is the largest yet reported for such closely related soil bacteria (97.8%–98.9% identity of 16S rRNA genes). The extent of gene deletion, duplication, and acquisition is in concert with the biogeographic history of the symbioses and host plant speciation. Host plant isolation favored genome contraction, whereas host plant diversification favored genome expansion. The results support the idea that major genome expansions as well as reductions can occur in facultative symbiotic soil bacteria as they respond to new environments in the context of their symbioses
Healing of bronchopleural fistula using a modified Dumon stent: a case report
BACKGROUND: Brochopleural fistula following lung resection is a therapeuric challenge for thoracic surgeons. CASE PRESENTATION: We describe a case of late bronchopleural fistula after right extrapleural pneumonectomy for malignant mesothelioma. Bronchoscopic attempts to repair it were unsuccessful. CONCLUSION: The use of a modified Y Dumon stent associated with glue apposition on the bronchial stump allowed us to close the fistula without the need of any surgical repair
Insulin-like growth factor receptor 1 (IGF1R) expression and survival in surgically resected non-small-cell lung cancer (NSCLC) patients
Background: The purpose of this study is to investigate the prognostic role of insulin-like growth factor receptor 1 (IGF1R) expression in surgically resected non-small-cell lung cancer (NSCLC). Patient characteristics and methods: This retrospective study was conducted in 369 stage I-II-IIIA, surgically resected, NSCLC patients. Patients exposed to anti-epidermal growth factor receptor (EGFR) agents were excluded. IGF1R expression was evaluated by immunohistochemistry in tissue microarray sections. Results: A positive IGF1R expression (score ≥ 100) was observed in 282 cases (76.4%) and was significantly associated with squamous cell histology (P = 0.04) and with grade III differentiation (P = 0.02). No difference in survival was observed between the positive and negative group when score 100 was used as cut-off for discriminating a positive versus a negative IGF1R result (52 versus 48 months, P = 0.99) or when median value of IGF1R expression was used (45 versus 55 months, P = 0.36). No difference in survival was observed between IGF1R-positive and -negative patients in a subgroup of stage I-II adenocarcinoma (n = 137) with known EGFR mutation and copy number status. Conclusions: IGF1R expression does not represent a prognostic factor in resected NSCLC patients. Patients with squamous cell carcinoma overexpress IGF1R more frequently than patients with nonsquamous histology, justifying the different sensitivity to anti-IGF1R agents observed in clinical trial
Phenotypic diversity of T cells in human primary and metastatic brain tumors revealed by multiomic interrogation.
The immune-specialized environment of the healthy brain is tightly regulated to prevent excessive neuroinflammation. However, after cancer development, a tissue-specific conflict between brain-preserving immune suppression and tumor-directed immune activation may ensue. To interrogate potential roles of T cells in this process, we profiled these cells from individuals with primary or metastatic brain cancers via integrated analyses on the single-cell and bulk population levels. Our analysis revealed similarities and differences in T cell biology between individuals, with the most pronounced differences observed in a subgroup of individuals with brain metastasis, characterized by accumulation of CXCL13-expressing CD39 <sup>+</sup> potentially tumor-reactive T (pTRT) cells. In this subgroup, high pTRT cell abundance was comparable to that in primary lung cancer, whereas all other brain tumors had low levels, similar to primary breast cancer. These findings indicate that T cell-mediated tumor reactivity can occur in certain brain metastases and may inform stratification for treatment with immunotherapy
FLNA is implicated in pulmonary neuroendocrine tumors aggressiveness and progression
Pulmonary neuroendocrine tumors (PNTs) comprise different neoplasms, ranging from low grade carcinoids to the highly malignant small cell lung cancers. Several studies identified the cytoskeleton protein Filamin A (FLNA) as determinant in cancer progression and metastasis, but the role of FLNA in PNT aggressiveness and progression is still unknown. We evaluated FLNA expression in PNTs with different grade of differentiation, the role of FLNA in cell proliferation, colony formation, angiogenesis, cell adhesion and migration in PNT cell line (H727 cells) and primary cultures and the possible interaction between FLNA and Rap1-GTPase. FLNA is highly expressed in PNTs with high malignant grade. FLNA silencing reduces cyclin D1 levels (-51\uc2\ub15, p < 0.001) and cell proliferation in PNT cells (-37\uc2\ub14, p < 0.05), colony formation and VEGF expression (-39\uc2\ub19%, p < 0.01) in H727 cells. FLNA and Rap1 co-localize in cellular protrusions and FLNA silencing up-regulates Rap1 expression (+73\uc2\ub118%, p < 0.01). Rap1 silencing prevents cell adhesion increase (+43%\uc2\ub118%, p < 0.01) and cell migration decrease (-56\uc2\ub17%, p < 0.01) induced by FLNA silencing, without affecting cell proliferation reduction. In conclusion, FLNA is implicated in PNT progression, in part through Rap1, thus providing a potential diagnostic and therapeutic target
Neurochemical Changes in the Mouse Hippocampus Underlying the Antidepressant Effect of Genetic Deletion of P2X7 Receptors.
Recent investigations have revealed that the genetic deletion of P2X7 receptors (P2rx7) results in an antidepressant phenotype in mice. However, the link between the deficiency of P2rx7 and changes in behavior has not yet been explored. In the present study, we studied the effect of genetic deletion of P2rx7 on neurochemical changes in the hippocampus that might underlie the antidepressant phenotype. P2X7 receptor deficient mice (P2rx7-/-) displayed decreased immobility in the tail suspension test (TST) and an attenuated anhedonia response in the sucrose preference test (SPT) following bacterial endotoxin (LPS) challenge. The attenuated anhedonia was reproduced through systemic treatments with P2rx7 antagonists. The activation of P2rx7 resulted in the concentration-dependent release of [3H]glutamate in P2rx7+/+ but not P2rx7-/- mice, and the NR2B subunit mRNA and protein was upregulated in the hippocampus of P2rx7-/- mice. The brain-derived neurotrophic factor (BDNF) expression was higher in saline but not LPS-treated P2rx7-/- mice; the P2rx7 antagonist Brilliant blue G elevated and the P2rx7 agonist benzoylbenzoyl ATP (BzATP) reduced BDNF level. This effect was dependent on the activation of NMDA and non-NMDA receptors but not on Group I metabotropic glutamate receptors (mGluR1,5). An increased 5-bromo-2-deoxyuridine (BrdU) incorporation was also observed in the dentate gyrus derived from P2rx7-/- mice. Basal level of 5-HT was increased, whereas the 5HIAA/5-HT ratio was lower in the hippocampus of P2rx7-/- mice, which accompanied the increased uptake of [3H]5-HT and an elevated number of [3H]citalopram binding sites. The LPS-induced elevation of 5-HT level was absent in P2rx7-/- mice. In conclusion there are several potential mechanisms for the antidepressant phenotype of P2rx7-/- mice, such as the absence of P2rx7-mediated glutamate release, elevated basal BDNF production, enhanced neurogenesis and increased 5-HT bioavailability in the hippocampus
Three deaf mice: mouse models for TECTA-based human hereditary deafness reveal domain-specific structural phenotypes in the tectorial membrane
Tecta is a modular, non-collagenous protein of the tectorial membrane, an extracellular matrix of the cochlea essential for normal hearing. Missense mutations in Tecta cause dominant forms of nonsyndromic deafness and a genotype-phenotype correlation has been reported in humans, with mutations in different Tecta domains causing mid- or high-frequency hearing impairments that are either stable or progressive. Three mutant mice were created as models for human Tecta mutations; the TectaL1820F, G1824D/+ mouse for zona pellucida (ZP) domain mutations causing stable mid-frequency hearing loss in a Belgian family, the TectaC1837G/+ mouse for a ZP-domain mutation underlying progressive mid-frequency hearing loss in a Spanish family, and the TectaC1619S/+ mouse for a zonadhesin-like (ZA) domain mutation responsible for progressive, high-frequency hearing loss in a French family. Mutations in the ZP and ZA domains generate distinctly different changes in the structure of the tectorial membrane. ABR thresholds in the 8-40 kHz range are elevated by 30-40 dB in the ZP-domain mutants, whilst those in the ZA-domain mutant are elevated by 20-30 dB. The phenotypes are stable and no evidence has been found for a progressive deterioration in tectorial membrane structure or auditory function. Despite elevated auditory thresholds, the Tecta mutant mice all exhibit an enhanced tendency to have audiogenic seizures in response to white noise stimuli at low sound pressure levels (≤84 dB SPL), revealing a previously unrecognised consequence of Tecta mutations. These results, together with those from previous studies, establish an allelic series for Tecta unequivocally demonstrating an association between genotype and phenotype
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