Short poly(ethylene glycol) block initiation of poly(l-lactide) di-block copolymers: a strategy for tuning the degradation of resorbable devices

The current range of medical applications of resorbable polyesters could be hugely expanded if more effective strategies for tailoring degradation rate were available. Block copolymerisation with PEG has been shown to reduce degradation times, however, to date, this has relied on the addition of PEG to short lengths of polyester. This results in copolymers with high fractions of PEG and low molecular weights, reducing the potential range of applications. Furthermore, there has been no systematic study on the relative lengths of the blocks. In this work, we employed short hydroxyl-functionalised methoxy-terminated mPEG to initiate the synthesis of PLLA, resulting in controlled di- block copolymers with short mPEG blocks and long PLLA blocks. A controlled series of polymers was made with PLLA lengths (60 < Mn (kg/mol) < 200) and mPEG lengths (550 < Mn (g/mol) < 5000) giving very low mPEG wt% (0.1 < wt% < 1.5). We found, that, despite the low fraction of mPEG, water uptake and the rate of hydrolytic degradation, k, increased. Significantly, k, for the polymers was dependent only on the presence of mPEG, and was little affected by mPEG length or PLLA length in the ranges studied. Moreover, mass loss began in all polymers when the Mn of the polymer fell below a threshold of about 20 kg/mol and depended on both the initial molecular weight of PLLA and the presence (but not the length) of mPEG. Short chain mPEG therefore provides a new route for targeted, temporal control of resorbable polyesters for biomedical devices

GPT-based Language Models meet Emojitaliano: A Preliminary Assessment Test between Automation and Creativity

Starting from the crowdsourcing experience of Pinocchio in Emojitaliano, the present paper intends to test Chat-GPT's ability to take on the Emojitaliano grammar and dedicated glossary to verify and reapply the Emojitaliano rules in order to produce translations on its own. A test of re-translation of Pinocchio is presented

Porcine vas deferens luminal pH is acutely increased by systemic xylazine administration

Data are accumulating to demonstrate that pH regulation in the male reproductive tract has a vital role in modulating sperm cell fertilizing capacity and, therefore, male fertility. Bicarbonate uptake by sperm cells is required for the achievement of motility levels required for fertilization. Vas deferens epithelial cells can carry out measurable bicarbonate secretion, but the available literature to date reports that the vas deferens luminal content is typically acidic. This study aimed to determine pH in the boar vas deferens lumen and whether modulatory mechanisms exist for regulation of pH in this compartment of the male reproductive tract. A fiber-optic pH probe was used to assess pH in the vas deferens of anesthetized adult boars. The mean pH, derived from multiple measurements at variable positions along the vas deferens lumen, was 7.39 ± 0.09. Furthermore, administration of xylazine, an alpha-2 adrenergic receptor agonist, rapidly (< 10 min) alkalinized the vas deferens lumen in most cases. Since the duct was transected proximal to the site of measurements, the observations rule out the possibility that alkalinization resulted from secretion in more proximal portions of the duct. These results indicate that the boar vas deferens lumen can be alkaline, and suggest that porcine vas deferens epithelia increase net bicarbonate secretion in vivo, following systemic alpha-2 adrenergic stimulation. This secretory response greatly changes the luminal environment to which sperm cells are exposed, which will initiate or enhance motility, and is expected to modulate male fertility

Supraorganized Collagen Enhances Schwann Cell Reactivity And Organization In Vitro.

We investigated the reactivity and expression of basal lamina collagen by Schwann cells (SCs) cultivated on a supraorganized bovine-derived collagen substrate. SC cultures were obtained from sciatic nerves of neonatal Sprague-Dawley rats and seeded on 24-well culture plates containing collagen substrate. The homogeneity of the cultures was evaluated with an SC marker antibody (anti-S-100). After 1 week, the cultures were fixed and processed for immunocytochemistry by using antibodies against type IV collagen, S-100 and p75NTR (pan neurotrophin receptor) and for scanning electron microscopy (SEM). Positive labeling with antibodies to the cited molecules was observed, indicating that the collagen substrate stimulates SC alignment and adhesion (collagen IV labeling - organized collagen substrate: 706.33 ± 370.86, non-organized collagen substrate: 744.00 ± 262.09; S-100 labeling - organized collagen: 3809.00 ± 120.28, non-organized collagen: 3026.00 ± 144.63, P < 0.05) and reactivity (p75NTR labeling - organized collagen: 2156.33 ± 561.78, non-organized collagen: 1424.00 ± 405.90, P < 0.05; means ± standard error of the mean in absorbance units). Cell alignment and adhesion to the substrate were confirmed by SEM analysis. The present results indicate that the collagen substrate with an aligned suprastructure, as seen by polarized light microscopy, provides an adequate scaffold for SCs, which in turn may increase the efficiency of the nerve regenerative process after in vivo repair.44682-

Regional citrate anticoagulation in CVVH: a new protocol combining citrate solution with a phosphate-containing replacement fluid

Regional citrate anticoagulation (RCA) is a valid anticoagulation method in continuous renal replacement therapies (CRRT) and different combination of citrate and CRRT solutions can affect acid-base balance. Regardless of the anticoagulation protocol, hypophosphatemia occurs frequently in CRRT. In this case report, we evaluated safety and effects on acid-base balance of a new RCA- continuous veno-venous hemofiltration (CVVH) protocol using an 18 mmol/L citrate solution combined with a phosphate-containing replacement fluid. In our center, RCA-CVVH is routinely performed with a 12 mmol/L citrate solution and a postdilution replacement fluid with bicarbonate (protocol A). In case of persistent acidosis, not related to citrate accumulation, bicarbonate infusion is scheduled. In order to optimize buffers balance, a new protocol has been designed using recently introduced solutions: 18 mmol/L citrate solution, phosphate-containing postdilution replacement fluid with bicarbonate (protocol B). In a cardiac surgery patient with acute kidney injury, acid-base status and electrolytes have been evaluated comparing protocol A (five circuits, 301 hours) vs. protocol B (two circuits, 97 hours): pH 7.39 ± 0.03 vs. 7.44 ± 0.03 (P < 0.0001), bicarbonate 22.3 ± 1.8 vs. 22.6 ± 1.4 mmol/L (NS), Base excess −2.8 ± 2.1 vs. −1.6 ± 1.2 (P = 0.007), phosphate 0.85 ± 0.2 vs. 1.3 ± 0.5 mmol/L (P = 0.027). Protocol A required bicarbonate and sodium phosphate infusion (8.9 ± 2.8 mmol/h and 5 g/day, respectively) while protocol B allowed to stop both supplementations. In comparison to protocol A, protocol B allowed to adequately control acid-base status without additional bicarbonate infusion and in absence of alkalosis, despite the use of a standard bicarbonate concentration replacement solution. Furthermore, the combination of a phosphate-containing replacement fluid appeared effective to prevent hypophosphatemia

"Spotto la quarantena": per una analisi dell'italiano scritto degli studenti universitari via social network in tempo di COVID-19

Per un\u2019analisi dell\u2019italiano scritto degli studenti universitari, un contesto privilegiato si trova in quei canali social di condivisione tra pari noti con la titolatura di \u201cSpotted\u201d. Attivi particolarmente su Instagram, si tratta di canali di interazione pubblica informale che forniscono elementi significativi all\u2019indagine sulle scritture spontanee dei giovani in rete. Questa ricerca presenta un corpus di oltre trentamila testi da Spotted universitari italiani. Concentrandoci sulle fasi COVID (e sul periodo immediatamente precedente), intendiamo illustrare come il corpus Spotted-Ita appaia funzionale a un\u2019indagine riferita alla comunicazione linguistica nell\u2019occasione di un\u2019esperienza unica e straordinaria vissuta dagli studenti universitari.\u201cSpotted\u201d posts represent one of the most popular forms of Computer mediated Communication (CMC) among university students in Italy, and as such, they represent a privileged context to analyze the Italian language used by students on the Web. This kind of informal communication channels is active especially on Instagram, and provides relevant insights on the spontaneous writing of young people. Based on Spotted-ITA Corpus, a corpus of over 30,000 posts retrieved from Italian Spotted accounts on Instagram, this paper presents a focus on the period of lockdown in Italy due to COVID pandemics and its immediately preceding period, showing how this corpus can be useful in analyzing the way Italian university students communicated during this unique and extraordinary experience