Self-assembly of supramolecular chemoenzymatic poly-l-phenylalanine

The self-assembly behavior of chemoenzymatic high molecular weight (ca. 30 000 Da) poly-L-phenylalanine (ePLP) and the nano-morphologies thereof are investigated. Interestingly, this supramolecular ePLP changes from a non-ordered secondary structure when solubilized in water to an a-helix with the addition of only 1 vol% HFIP co-solvent, and at a relatively low concentration (0.5 mg mL-1). The results also indicate a temperature-dependent structural stabilization, wherein the self-assembly process is mainly governed by hydrogen bonding. The analyses evidence self-assembly under controlled conditions to obtain nanotubes with an average diameter of 0.21 ± 0.04 µm, and above 100 µm length. Microbeam synchrotron radiation infrared (SRIR) spectroscopy demonstrates parallel orientations of the amide moieties in the a-helical structure, which is extraordinary for this long chain ePLP. The achievement of these highly homogeneous nanotubes is relevant since previous reports only demonstrated this arrangement for end-capped F-moc-containing short oligophenylalanines. In the same way, the conductivity behaviors of the nanotubular structure remained unchanged in the range of 273–313 K demonstrating its stability from hydrogen bonds, and also, direct dielectric measurements reveal a high orientation and stabilization by intra- and intermolecular hydrogen bonds in the nanotubes. These characteristics allow drug delivery assays with tetracycline-loaded nanotubes and further applications are envisaged.Peer ReviewedPostprint (author's final draft

Case study in failure analysis of accelerated life tests (ALT) on III-V commercial triple-junction concentrator solar cells

In this work the failure analysis carried out in III-V concentrator multijunction solar cells after a temperature accelerated life test is presented. All the failures appeared have been catastrophic since all the solar cells turned into low shunt resistances. A case study in failure analysis based on characterization by optical microscope, SEM, EDX, EQE and XPS is presented in this paper, revealing metal deterioration in the bus bar and fingers as well as cracks in the semiconductor structure beneath or next to the bus bar. In fact, in regions far from the bus bar the semiconductor structure seems not to be damaged. SEM images have dismissed the presence of metal spikes inside the solar cell structure. Therefore, we think that for these particular solar cells, failures appear mainly as a consequence of a deficient electrolytic growth of the front metallization which also results in failures in the semiconductor structure close to the bus bars

Core-collapse and Type Ia supernovae with the SKA

Core-collapse SNe (CCSNe): Systematic searches of radio emission from CCSNe are still lacking, and only targeted searches of radio emission from just some of the optically discovered CCSNe in the local universe have been carried out. Optical searches miss a significant fraction of CCSNe due to dust obscuration; CCSN radio searches are thus more promising for yielding the complete, unobscured star-formation rates in the local universe. The SKA yields the possibility to piggyback for free in this area of research by carrying out commensal, wide-field, blind transient survey observations. SKA1-SUR should be able to discover several hundreds of CCSNe in just one year, compared to about a dozen CCSNe that the VLASS would be able to detect in one year, at most. SKA, with an expected sensitivity ten times that of SKA1, is expected to detect CCSNe in the local Universe by the thousands. Therefore, commensal SKA observations could easily result in an essentially complete census of all CCSNe in the local universe, thus yielding an accurate determination of the volumetric CCSN rate. Type Ia SNe: We advocate for the use of the SKA to search for the putative prompt (~first few days after the explosion) radio emission of any nearby type Ia SN, via target-of-opportunity observations. The huge improvement in sensitivity of the SKA with respect to its predecessors will allow to unambiguously discern which progenitor scenario (single-degenerate vs. double-degenerate) applies to them.Comment: Proceedings of Science: Advancing Astrophysics with the Square Kilometre Array. Accepted version, including comments by the refere

Is the treatment with biological or non-biological DMARDS a modifier of periodontal condition in patients with rheumatoid arthritis?

Background and objective: Experimental models suggest the use of different therapy protocols in rheumatoid arthritis (RA) as modulators on periodontal condition. This study evaluated the effects of conventional drug treatment and anti-TNF therapy in patients with RA on microbiological and periodontal condition, establishing the association of markers of periodontal infection with indexes of rheumatic activity. Materials and methods: One hundred seventy nine individuals with RA were evaluated (62 with anti-TNF-. and 115 with only DMARDs). The periodontal evaluation included plaque and gingival indexes, bleeding on probing (BOP), clinical attachment loss (CAL), pocket depth (PD) and subgingival plaque samples for microbiological analysis. Rheumatologic evaluations included a clinical examination, rheumatoid factor (RF), antibodies against cyclic-citrullinated peptides (ACPAs), and activity markers (DAS28-ERS), high sensitive C-reactive protein (hs-CRP), erythrocyte sedimentation rate (ESR). Results: Anti-TNF-alpha therapy influenced periodontal microbiota with a higher frequency of T. denticola (p=0.01). Methotrexate combined with leflunomide exhibited a higher extension of CAL (p=0.005), and anti-TNF-alpha therapy with methotrexate was associated with a lower extension of CAL (p=0.05). The use of corticosteroids exerted a protective effect on the number of teeth (p=0.027). The type of DMARD affected P. gingivalis, T. forsythia and E. nodatum presence. Elevated ACPAs titers were associated with the presence of red complex periodontal pathogens (p=0.025). Bleeding on probing was associated with elevated CPR levels (p=0.05), and ESR was associated with a greater PD (p=0.044) and presence of red complex (p=0.030). Conclusion: Different pharmacological treatments for RA affect the clinical condition and subgingival microbiota

Interaction of HLA Class II rs9272219 and TMPO rs17028450 (Arg690Cys) Variants Affects Neuromyelitis Optica Spectrum Disorder Susceptibility in an Admixed Mexican Population

Neuromyelitis Optica Spectrum Disorder (NMOSD) is a demyelinating autoimmune disease of the central nervous system, more prevalent in individuals of non-European ancestry. Few studies have analyzed genetic risk factors in NMOSD, and HLA class II gene variation has been associated NMOSD risk in various populations including Mexicans. Thymopoietin (TMPO) has not been tested as a candidate gene for NMOSD or other autoimmune disease, however, experimental evidence suggests this gene may be involved in negative selection of autoreactive T cells and autoimmunity. We thus investigated whether the missense TMPO variant rs17028450 (Arg630Cys, frequent in Latin America) is associated with NMOSD, and whether this variant shows an interaction with HLA-class II rs9272219, previously associated with NMOSD risk. A total of 119 Mexican NMOSD patients, 1208 controls and 357 Native Mexican individuals were included. The HLA rs9272219 "T" risk allele frequency ranged from 21 to 68%, while the rs17028450 "T" minor allele frequency was as high as 18% in Native Mexican groups. Both rs9272219 and rs17028450 were significantly associated with NMOSD risk under additive models (OR = 2.48; p = 8 × 10(-10) and OR = 1.59; p = 0.0075, respectively), and a significant interaction between both variants was identified with logistic regression models (p = 0.048). Individuals bearing both risk alleles had an estimated 3.9-fold increased risk of NMOSD. To our knowledge, this is the first study reporting an association of TMPO gene variation with an autoimmune disorder and the interaction of specific susceptibility gene variants, that may contribute to the genetic architecture of NMOSD in admixed Latin American populations

Determining the role of external beam radiotherapy in unresectable intrahepatic cholangiocarcinoma: a retrospective analysis of 84 patients

<p>Abstract</p> <p>Background</p> <p>Intrahepatic cholangiocarcinoma (ICC) is the second most common type of primary liver cancer. Only few studies have focused on palliative radiotherapy used for patients who weren't suitable for resection by surgery. This study was conducted to investigate the effect of external beam radiotherapy (EBRT) for patients with unresectable ICC.</p> <p>Methods</p> <p>We identified 84 patients with ICC from December 1998 through December 2008 for retrospective analysis. Thirty-five of 84 patients received EBRT therapy five times a week (median dose, 50 Gy; dose range, 30-60 Gy, in fractions of 1.8-2.0 Gy daily; EBRT group); the remaining 49 patients comprised the non-EBRT group. Tumor response, jaundice relief, and survival rates were compared by Kaplan-Meier analysis. Patient records were reviewed and compared using Cox proportional hazard analysis to determine factors that affect survival time in ICC.</p> <p>Results</p> <p>After EBRT, complete response (CR) and partial response (PR) of primary tumors were observed in 8.6% and 28.5% of patients, respectively, and CR and PR of lymph node metastases were observed in 20% and 40% of patients. In 19 patients with jaundice, complete and partial relief was observed in 36.8% and 31.6% of patients, respectively. Median survival times were 5.1 months for the non-EBRT group and 9.5 months for the EBRT group (<it>P </it>= 0.003). One-and two-year survival rates for EBRT versus non-EBRT group were 38.5% versus 16.4%, and 9.6% versus 4.9%, respectively. Multivariate analysis revealed that clinical symptoms, larger tumor size, no EBRT, multiple nodules and synchronous lymph node metastases were associated with poorer prognosis.</p> <p>Conclusions</p> <p>EBRT as palliative care appears to improve prognosis and relieve the symptom of jaundice in patients with unresectable ICC.</p