On the behavior of reduced graphene oxide based electrodes coated with dispersed platinum by alternate current methods in the electrochemical degradation of reactive dyes

The electrochemical behavior of different carbon-based electrodes with and without nanoparticles of platinum electrochemically dispersed on their surface has been studied. Among others, reduced graphene oxide based electrodes was used to determine the best conditions for the decolorization/degradation of the reactive dye C.I. Reactive Orange 4 in sulfuric medium. Firstly, the electrochemical behavior was evaluated by cyclic voltammetry. Secondly, different electrolyses were performed using two cell configurations: cell with anodic and cathodic compartments separated (divided configuration) and without any separation (undivided configuration). The best results were obtained when reduced graphene oxide based anodes were used. The degree of decolorization was monitored by spectroscopic methods and high performance liquid chromatography. It was found that all of them followed pseudo-first order kinetics. When reduced graphene oxide-based electrodes coated with dispersed platinum by alternate current methods electrodes were used, the lowest energy consumption and the higher decolorization kinetics rate were obtained. Scanning Electronic Microscopy was used to observe the morphological surface differences.

The Prediction of Shunt Response in Idiopathic Normal-Pressure Hydrocephalus Based on Intracranial Pressure Monitoring and Lumbar Infusion

BACKGROUND

Intracranial pressure (ICP) monitoring and infusion studies have long been used in the preoperative workup of patients with suspected idiopathic normal-pressure hydrocephalus (iNPH). We have analysed the predictive values of different measures derived from both investigations, emphasising the differences between responders and nonresponders.

MATERIALS AND METHODS

ICP monitoring and lumbar infusion studies were routinely performed during a 6-year period. Shunting was proposed when the resistance to cerebrospinal fluid outflow (ROUT) >12 mmHg/ml/min and/or a minimum 15 % of slow waves were detected. The outcome was evaluated 6 months after surgery. Recorded data from ICP monitoring were mean pressure and pulse amplitude, the total percentage of slow waves and the presence of different types of slow waves following the classification proposed by Raftopoulos et al. Recorded data from lumbar infusion studies were mean values of pressure and pulse amplitude during three epochs (basal, early infusion and plateau), ROUT and the pulsatility response to the increase in mean pressure during the infusion. This response was quantified by two pulse amplitude indexes: the pulse amplitude index during the early infusion stage (A1) and the pulse amplitude index during the plateau stage (A2).

RESULTS

Thirty shunted patients were evaluated at the end of the follow-up and 23 (76.7 %) of them improved. Differences in the percentage of slow waves, ROUT and both pulsatility indexes were not statistically significant. The proportion of patients with great symmetrical waves and pulse amplitude during the early infusion stage were higher in responders (p < 0.05). The predictive analysis yielded the highest accuracy, with ROUT and A1 as a logical "OR" combination.

CONCLUSION

The combined use of ICP monitoring and lumbar infusion to forecast the response to shunting in patients with suspected iNPH did not improve the accuracy provided by any of them alone.

[Epidemiological surveillance for multidrug-resistant microorganisms in a general ICU]

OBJECTIVE

Multidrug resistant (MDR) microorganisms represent a threat for patients admitted in Intensive Care Units (ICUs). The objective of the present study is to analyse the results of epidemiological surveillance cultures for these microorganisms in one of these units.

METHODS

General ICU. Retrospective analysis, descriptive statistics. Analysis of epidemiological surveillance cultures for MDR microorganisms in 2015. Studied microorganisms: Methicillin-resistant Staphylococcus aureus (MRSA), ESBL-and/or carbapenemase-producing Klebsiella pneumoniae (CESBL-KP) and MDR Acinetobacter baumannii (MDRAB).

RESULTS

One thousand, two hundred and fifty nine patients admitted. A total of 2,234 specimens from 384 patients were analysed (690, 634, 62 and 286 were rectal, throat, nasal and skin swabs respectively). Global APACHE II was 18.3 ± 8 versus 21.7 ± 7.8 in patients colonized/infected on admission. Global mortality was 19.7% versus 22.3% in patients colonized/infected on admission. The higher sensitivities achieved with the different samples for the different microorganism detection were as follows. MRSA: 79% and 90% for nasal and nasal + throat swabs, respectively. MDRAB: 80% and 95% for throat and throat + rectal swabs, respectively. CESBL-KP: 95% and 98% for rectal and rectal + throat swabs, respectively. 94 out of the 384 patients (24.4%) were colonized/infected with MDR at admission. 134 patients (10.6% of the total patients admitted) were colonized/infected with a total of 169 MMR during the hospital stay. MRSA has the earliest colonization/infection (9.2 ± 6.4days) and ESBL-producing Enterobacteriaceae, the latest (18.7± 16.4 days).

CONCLUSIONS

24.4% of patients were colonized/infected by MDR at admission. Nasal, throat and rectal swabs were the most effective specimens for recovering MRSA, MDRAB and CESBL-KP, respectively. The combination of two specimens improves MDR detection except for CESBL-KP. Skin swabs are worthless. The most prevalent MDR at admission were ESBL-producing Enterobacteriaceae while the most frequent hospital acquired MDR was MDRAB..

Nuevos táxones animales descritos en la península Ibérica y Macaronesia desde 1994 (XX)

Esta actual relación de nuevos táxones incluye 501 registros (378 especies, 55 géneros o subgéneros, 43 categorías supragenéricas y 25 subespecies), publicados en 251 trabajos, principalmente en 2015 y 2016. Se incluyen también aquellos registros publicados con anterioridad y que no habían sido recogidos en las recopilaciones anteriores. Todos ellos proceden del área geográfica objeto de la revisión y de fondos abisales próximos, o su distribución conocida la incluye o engloban categorías presentes en esa zona.

Evaluation of a real-time PCR assay for rectal screening of OXA-48-producing Enterobacteriaceae in a general intensive care unit of an endemic hospital

Carbapenemase-producing Enterobacteriaceae are increasing worldwide. Rectal screening for these bacteria can inform the management of infected and colonized patients, especially those admitted to intensive care units (ICUs). A laboratory developed, qualitative duplex real-time polymerase chain reaction assay for rapid detection of OXA-48-like and VIM producing Enterobacteriaceae, performed on rectal swabs, was designed and evaluated in an intensive care unit with endemic presence of OXA-48. During analytical assay validation, no cross-reactivity was observed and 100% sensitivity and specificity were obtained for both bla_OXA-48-like and bla_VIM in all spiked clinical samples. During the clinical part of the study, the global sensitivity and specificity of the real-time PCR assay for OXA-48 detection were 95.7% and 100% (P=0.1250), respectively, in comparison with culture; no VIM-producing Enterobacteriaceae were detected. Clinical features of patients in the ICU who were colonized or infected with OXA-48 producing Enterobacteriaceae, including outcome, were analyzed. Most had severe underlying conditions, and had risk factors for colonization with carbapenemase-producing Enterobacteriaceae before or during ICU admission, such as receiving previous antimicrobial therapy, prior healthcare exposure (including long-term care), chronic disease, immunosuppression and/or the presence of an intravascular catheter and/or mechanical ventilation device. The described real-time PCR assay is fast (~2-3hours, if DNA extraction is included), simple to perform and results are easy to interpret, features which make it applicable in the routine of clinical microbiology laboratories. Implementation in endemic hospitals could contribute to early detection of patients colonized by OXA-48 producing Enterobacteriaceae and prevention of their spread.

Whole genome sequencing of Shigella sonnei through PulseNet Latin America and Caribbean: advancing global surveillance of foodborne illnesses

Objectives

Shigella sonnei is a globally important diarrhoeal pathogen tracked through the surveillance network PulseNet Latin America and Caribbean (PNLA&C), which participates in PulseNet International. PNLA&C laboratories use common molecular techniques to track pathogens causing foodborne illness. We aimed to demonstrate the possibility and advantages of transitioning to whole genome sequencing (WGS) for surveillance within existing networks across a continent where S. sonnei is endemic.

Methods

We applied WGS to representative archive isolates of S. sonnei (n = 323) from laboratories in nine PNLA&C countries to generate a regional phylogenomic reference for S. sonnei and put this in the global context. We used this reference to contextualise 16 S. sonnei from three Argentinian outbreaks, using locally generated sequence data. Assembled genome sequences were used to predict antimicrobial resistance (AMR) phenotypes and identify AMR determinants.

Results

S. sonnei isolates clustered in five Latin American sublineages in the global phylogeny, with many (46%, 149 of 323) belonging to previously undescribed sublineages. Predicted multidrug resistance was common (77%, 249 of 323), and clinically relevant differences in AMR were found among sublineages. The regional overview showed that Argentinian outbreak isolates belonged to distinct sublineages and had different epidemiologic origins.

Conclusions

Latin America contains novel genetic diversity of S. sonnei that is relevant on a global scale and commonly exhibits multidrug resistance. Retrospective passive surveillance with WGS has utility for informing treatment, identifying regionally epidemic sublineages and providing a framework for interpretation of prospective, locally sequenced outbreaks.

Oxyfluoride glass–ceramic fibers doped with Nd3+: structural and optical characterization

Selective excitation in an oxyfluoride glass–ceramic optical fiber containing LaF₃ nanocrystals doped with Nd³⁺.

A combined docosahexaenoic acid–thyroid hormone protocol upregulates rat liver β-Klotho expression and downstream components of FGF21 signaling as a potential novel approach to metabolic stress conditions

We study the mechanism of how liver preconditioning by a DHA and triiodothyronine combined protocol underlies peroxisome-proliferator activated receptor α (PPARα)-fibroblast growth factor 21 (FGF21) upregulation.

Multidrug-Resistant Outbreak-Associated Salmonella Strains in Irrigation Water from the Metropolitan Region, Chile

Salmonella enterica (S. enterica) is the main cause of foodborne diseases in the Chilean population. With the aim of characterizing the presence of S. enterica in bodies of water, samples from 40 sources were obtained, including rivers and irrigation canals used by agricultural farms in the most populated regions of Chile. As result, 35 S. enterica isolates belonging to several serotypes were detected, with the highest frequency represented by Typhimurium and Enteritidis. All strains showed phenotypic antimicrobial resistance, and most of them were multiresistant to critically important antimicrobials. In addition, the pulse-field gel electrophoresis analysis using XbaI and BlnI endonucleases showed that seven Salmonella isolates belonging to serotypes Typhimurium, Enteritidis and Infantis had identical pulsotypes to outbreak-associated clinical isolates detected in the Chilean population, suggesting a public health risk of water pollution in this region. Among sampling sites, the higher detection rates were observed in rural than urban and peri-urban areas, suggesting that the animal husbandry might contribute for environmental dispersion of this pathogen. Future efforts should address the characterization of cause-and-effect relationship between water contamination and foodborne disease, including the implementation of surveillance programmes to tackle potential risks for both human and animal populations.

Tuberculosis in prisoners and their contacts in Chile: estimating incidence and latent infection

SETTING

Contact investigation of tuberculosis (TB) patients in Chilean prisons.

OBJECTIVE

1) To estimate TB incidence and the prevalence of latent tuberculous infection (LTBI) among prisoners and their contacts; and 2) to determine factors associated with disease transmission.

DESIGN

Cross-sectional study conducted in 46 prisons (51% of the total prison population) to assess the prevalence of and risk factors for LTBI among contacts of prisoners newly diagnosed with pulmonary TB. We used in vitro interferon-gamma release assays to establish LTBI and a questionnaire to address risk factors.

RESULTS

During the 1-year follow-up, we studied 418 contacts of 33 active TB cases. We found high TB incidence (123.9 per 100,000 prisoners) and high LTBI prevalence (29.4%) among contacts. LTBI rates are significantly higher in prison inmates than in non-prisoners (33.2% vs. 15.6%). Male sex, illicit drugs, malnutrition, corticosteroid use, low educational level and sharing a cell with a case increase the risk of LTBI. Multivariate analyses showed that corticosteroid use, duration of incarceration and overcrowding are the most relevant determinants for LTBI among all contacts.

CONCLUSIONS

Our results confirm that incarceration increases the risk of tuberculous infection and TB disease, and that it was associated not only with origin from vulnerable groups, but also with the prison environment. Reinforcing TB control is essential to prevent TB transmission in prisons.

28th Annual DIA EuroMeeting (April 6-8, 2016 - Hamburg, Germany)

The 28(th) Drug Information Association (DIA) Annual EuroMeeting took place in Hamburg, Germany, gathering together participants from different industries, organizations, academic research centers, regulatory agencies and health ministries, mainly from the E.U. The conference began with a regulatory Town Hall meeting focusing on the E.U. Medicines Agencies Network strategy to 2020. This was followed by an opening plenary session where the diverse roles of innovation in drug development were discussed. Areas for discussion over the meeting were classified into 14 main themes, and for each session, profession¬als from the pharmaceutical industry, regulatory agencies and health ministries, as well as delegates from patient organizations, presented their considerations for debate. This report covers some regulatory sessions presented at the meeting.

Neutrophil gelatinase-associated lipocalin is a biomarker of acute-on-chronic liver failure and prognosis in cirrhosis

BACKGROUND & AIMS

Acute-on-chronic liver failure (ACLF) is a syndrome that occurs in cirrhosis characterized by organ failure(s) and high mortality rate. There are no biomarkers of ACLF. The LCN2 gene and its product, neutrophil gelatinase-associated lipocalin (NGAL), are upregulated in experimental models of liver injury and cultured hepatocytes as a result of injury by toxins or proinflammatory cytokines, particularly Interleukin-6. The aim of this study was to investigate whether NGAL could be a biomarker of ACLF and whether LCN2 gene may be upregulated in the liver in ACLF.

METHODS

We analyzed urine and plasma NGAL levels in 716 patients hospitalized for complications of cirrhosis, 148 with ACLF. LCN2 expression was assessed in liver biopsies from 29 additional patients with decompensated cirrhosis with and without ACLF.

RESULTS

Urine NGAL was markedly increased in ACLF vs. no ACLF patients (108(35-400) vs. 29(12-73)μg/g creatinine; p<0.001) and was an independent predictive factor of ACLF; the independent association persisted after adjustment for kidney function or exclusion of variables present in ACLF definition. Urine NGAL was also an independent predictive factor of 28day transplant-free mortality together with MELD score and leukocyte count (AUROC 0.88(0.83-0.92)). Urine NGAL improved significantly the accuracy of MELD in predicting prognosis. The LCN2 gene was markedly upregulated in the liver of patients with ACLF. Gene expression correlated directly with serum bilirubin and INR (r=0.79; p<0.001 and r=0.67; p<0.001), MELD (r=0.68; p<0.001) and Interleukin-6 (r=0.65; p<0.001).

CONCLUSIONS

NGAL is a biomarker of ACLF and prognosis and correlates with liver failure and systemic inflammation. There is remarkable overexpression of LCN2 gene in the liver in ACLF syndrome.

LAY SUMMARY

Urine NGAL is a biomarker of acute-on-chronic liver failure (ACLF). NGAL is a protein that may be expressed in several tissues in response to injury. The protein is filtered by the kidneys due to its small size and can be measured in the urine. Ariza, Graupera and colleagues found in a series of 716 patients with cirrhosis that urine NGAL was markedly increased in patients with ACLF and correlated with prognosis. Moreover, gene coding NGAL was markedly overexpressed in the liver tissue in ACLF.

Liver Transplant From Unexpected Donation After Circulatory Determination of Death Donors: A Challenge in Perioperative Management

Unexpected donation after circulatory determination of death (uDCD) liver transplantation is a complex procedure, in particular when it comes to perioperative recipient management. However, very little has been published to date regarding intraoperative and immediate postoperative care in this setting. Herein, we compare perioperative events in uDCD liver recipients with those of a matched group of donation after brain death liver recipients. We demonstrate that the former group of recipients suffers significantly greater hemodynamic instability and derangements in coagulation following graft reperfusion. Based on our experience, we recommend a proactive recipient management strategy in uDCD liver transplantation that involves early use of vasopressor support; maintaining adequate intraoperative levels of red cells, platelets, and fibrinogen; and routinely administering tranexamic acid before graft reperfusion.

The use of coancestry based on shared segments for maintaining genetic diversity

We have evaluated the use of genomic coancestry coefficients based on shared segments for the maintenance of genetic diversity through optimal contributions methodology for populations of three different Austrian cattle breeds. This coancestry measure has been compared with the genomic coancestry coefficient calculated on a SNP-by-SNP basis and with pedigree-based coancestry. The regressions of the shared segments coancestry on the other two coefficients suggest that the former mainly reflect Identity By Descent but with the advantage over pedigree-based coancestry of providing the realized Identity By Descent rather than an expectation. The effective population size estimated from the rate of coancestry based on shared segments was very similar to those obtained with the other coefficients and of small magnitude (from 26.24 to 111.90). This result highlights the importance of implementing active management strategies to control the increase of inbreeding and the loss of genetic diversity in livestock breeds, even when the population size is reasonably large. One problem for the implementation of coancestry based on shared segments is the need of estimating the gametic phases of the SNPs which, given the techniques used to obtain the genotypes, are a priori unknown. This study shows, through computer simulations, that using estimates of gametic phases for computing coancestry based on shared segments does not lead to a significant loss in the diversity maintained. This has been shown to be true even when the size of the population is very small as it is usually the case in populations subjected to conservation programmes.

A report on the outbreak of Zika virus on Easter Island, South Pacific, 2014

Zika virus (ZIKV) is an emerging mosquito-borne flavivirus circulating in Asia and Africa. In 2013, a large outbreak was reported on the archipelago of French Polynesia. In this study, we report the detection and molecular characterization of Zika virus for the first time in Chile from an outbreak among the inhabitants of Easter Island. A total of 89 samples from patients suspected of having ZIKV infection were collected between the period from January to May, 2014. Molecular diagnosis of the virus was performed by RT-PCR followed by the sequencing of the region containing the NS5 gene. A comparison of the viral nucleic acid sequence with those of other strains of ZIKA virus was performed using the MEGA software. Fifty-one samples were found positive for ZIKV by RT-PCR analysis. Further analysis of the NS5 gene revealed that the ZIKV strains identified in Easter Island were most closely related to those found in French Polynesia (99.8 to 99.9% nt and 100% aa sequence identity). These results strongly suggest that the transmission pathway leading to the introduction of Zika virus on Easter Island has its origin in French Polynesia.

Vagus nerve stimulation therapy for treatment-resistant epilepsy: a 15-year experience at a single institution

OBJECTIVE

Treatment-resistant epilepsy (TRE) occurs in 20-30% of patients. The goal of this study is to assess the efficacy and safety of vagus nerve stimulation (VNS) in this group of patients, including adult and pediatric populations and several off-label indications.

METHODS

This is a retrospective review of 59 consecutive patients in whom 60 VNS devices were implanted at a single institution during a 15-year period. Patients were evaluated in the Multidisciplinary Epilepsy Committee and complete presurgical workup was performed. The series included indications not approved by the FDA, such as children under 12 years of age, pregnancy and right-sided VNS. Performing the procedure on an out-patient basis was recently adopted, minimizing hospital length of stay.

RESULTS

There were 42 adults and 17 children (14 under 12 years of age) and the mean age at implantation was 26 years. Duration of VNS therapy ranged from 6 months to 9 years. For the entire cohort, the mean percentage seizure reduction was 31.37%. Twenty patients (34.48%) were considered responders (seizure reduction ≥50%); 7 patients (12.06%) had seizure reduction of ≥75% and 2 patients had seizure control of ≥90% (3.4%). The patient in whom right-sided VNS was implanted achieved the same reduction in seizure burden and the patient who became pregnant could reduce antiepileptic drugs dosage, without complications. Side-effects were mild and there were no permanent nerve injuries. One patient died in the follow-up due to psychiatric disorders previously known.

CONCLUSIONS

VNS is a safe and effective palliative treatment for TRE patients. There are an increasing number of indications and further randomized trials would potentially expand the number of patients who may benefit from it. A multidisciplinary team is crucial for a complete preoperative evaluation and selection of the optimal candidates for the treatment.

Experience in retake analysis for digital mammography at a university hospital

Data from one digital mammograph (flat detector active area of 19.2 × 23 cm(2)) were collected over a 1-year period using locally developed software in order to evaluate retakes, their rates, their causes and the possible measures to reduce their occurrence. Among them, 7.1 % of the images were marked as repetitions, and in 16 % of the studies, at least one image was repeated. When evaluating causes of retakes, the primary cause was incorrect positioning (49 %), closely followed by additional retakes in cases of large breasts (44 %). When dealing with large breasts and using a small flat panel, additional images were necessary to fully visualise the breast, and as a consequence, some breast regions received repeated radiation exposure. Moreover, a small detector increases retakes in breasts slightly wrongly positioned. To try and reduce the retake rate, it is important to plan training sessions based on images selected from the retake analysis.

In vitro performance of ceramic coatings obtained by high velocity oxy-fuel spray

Hydroxyapatite coatings obtained by plasma-spraying have been used for many years to improve biological performance of bone implants, but several studies have drawn attention to the problems arising from high temperatures and the lack of mechanical properties. In this study, plasma-spraying is substituted by high velocity oxy-fuel (HVOF) spray, with lower temperatures reached, and TiO2 is added in low amounts to hydroxyapatite in order to improve the mechanical properties. Four conditions have been tested to evaluate which are those with better biological properties. Viability and proliferation tests, as well as differentiation assays and morphology observation, are performed with human osteoblast cultures onto the studied coatings. The hydroxyapatite-TiO2 coatings maintain good cell viability and proliferation, especially the cases with higher amorphous phase amount and specific surface, and promote excellent differentiation, with a higher ALP amount for these cases than for polystyrene controls. Observation by SEM corroborates this excellent behaviour. In conclusion, these coatings are a good alternative to those used industrially, and an interesting issue would be improving biological behaviour of the worst cases, which in turn show the better mechanical properties.

Untersuchungen über die Kinetik der Spaltung von Di- und Tripeptiden

Für eine Gruppe von Di- und Tripeptiden wurden die Geschwindigkeitskonstanten sowie die Arrhenius schen Aktivierungsenergien und Aktionskonstanten der sauren Hydrolyse der einzelnen Peptidbindungen gemessen. Zeitgesetz und Abstufungen der Aktivierungsenergien lassen sich nur unter bestimmten Annahmen über die Solvatation der Reaktionsteilnehmer auf der Grundlage des Ingold- Benderschen Mechanismus interpretieren. Aktionskonstante und Aktivierungsenergien weisen einen symbaten Gang auf.

NSAID-induced urticaria/angioedema does not evolve into chronic urticaria: a 12-year follow-up study

BACKGROUND

Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most frequent medicaments involved in drug hypersensitivity reactions, with NSAID-induced urticaria/angioedema (NIUA) being the most frequent clinical entity. The natural evolution of NIUA has been suggested to lead to chronic urticaria (CU) in an important proportion of patients, such that NIUA may therefore precede CU. Our aim was to verify whether these entities are related by following up a large cohort of patients with NIUA as well as a control group over a long period of time.

METHODS

The study comprised three groups: (i) patients with a confirmed history of NIUA (more than two episodes with at least two different NSAIDs or positive drug provocation tests), (ii) patients with more than two episodes of urticaria/angioedema to a single NSAID with good tolerance to a strong COX-1 inhibitor and/or evidence by in vivo tests supporting specific IgE antibodies to the drug (single NSAID-induced urticaria/angioedema, SNIUA), and (iii) controls who tolerated NSAIDs. All cases in the three groups were followed up over a period of 12 years.

RESULTS

There were 190 patients with NIUA (64.6% female; mean age 43.71 ± 15.82 years, 110 with SNIUA, and 152 controls. At the 12-year evaluation, 12 patients with NIUA (6.15%) had developed CU over a 1- to 8-year period. Similar proportions were seen in SNIUA and controls.

CONCLUSIONS

Nonsteroidal anti-inflammatory drugs-induced urticaria/angioedema does not seem to precede the onset of CU over the medium term. Further research including a longer follow-up is necessary to verify this observation.

A new generation of poly(lactide/ε-caprolactone) polymeric biomaterials for application in the medical field

Thermoplastic biodegradable polymers displaying an elastomeric behavior are greatly valued for the regeneration of soft tissues and for various medical devices. In this work, terpolymers composed of ε-caprolactone (CL), D-lactide (D-LA), and L-lactide (L-LA) were synthesized. These poly(lactide-ε-caprolactone) (PLCLs) presented an elevated randomness character (R∼1), glass transition temperatures (Tg ) higher than 20°C and adjusted L-LA content. In this way, the L-LA average sequence length (/L-LA ) was reduced to below 3.62 and showed little or no crystallization capability during in vitro degradation. As a result, the obtained materials underwent homogenous degradation exhibiting KMw ranging from 0.030 to 0.066 d(-1) and without generation of crystalline remnants in advanced stages of degradation. Mechanical performance was maintained over a period of 21 days for a rac-lactide-ε-caprolactone copolymer composed of ∼85% D,L-LA and ∼15% CL and also for a terpolymer composed of ∼72% L-LA, ∼12% D-LA and ∼16% CL. Terpolymers having L-LA content from ∼60 to 70% and CL content from ∼10 to 27% were also studied. In view of the results, those materials having CL and D-LA units disrupting the microstructural arrangement of the L-LA crystallizable chains, an L-LA content <72% and a random distribution of sequences, may display proper and tunable mechanical behavior and degradation performance for a large number of medical applications. Those with a CL content from 15 to 30% will fulfill the demand of elastomeric materials of Tg higher than 20°C whereas those with a CL content from 5 to 15% might be applied as ductile stiff materials.

On the temporal behavior of Nd3+ random lasers

The temporal dynamics of random laser emission from Nd-doped crystal powders has been investigated by using an improved detection device. The precise conditions to detect high contrast, fast oscillations are described. The measured period is about one order of magnitude shorter than the one given in the literature for relaxation oscillations in these materials. The origin of these differences is discussed.