The role of confinement loss in highly nonlinear silica holey fibers

Small-core holey fibers (HFs) can offer tight mode confinement, and are, therefore, attractive for highly nonlinear fiber applications. However, we show here that confinement loss can significantly degrade the performance of devices based on such small core fibers. We also identify a range of fiber designs that result in high fiber nonlinearity and low confinement loss. In particular, we show that pure silica HFs can exhibit effective nonlinearities more than 50 times higher than conventional fibers, and that the confinement loss can be lowered below the loss of standard fiber types

Patient-specific cardiovascular superelastic NiTi stents produced by laser powder bed fusion

To date, there is a general lack of customizability within the selection of endovascular devices for catheter-based vascular interventions. Laser powder bed fusion (LPBF) has been flexibly exploited to produce customized implants using conventional biomedical alloys for orthopedic and dental applications. Applying LPBF for cardiovascular applications, patient-specific stents can be produced with small struts (approximately 100-300 µm), variable geometries, and clinically used metals capable of superelastic behaviour at body temperature (eg. equiatomic nickel-titanium alloys, NiTi). Additionally, the growing availability and use of patient-specific 3D models provides a unique opportunity to outline the necessary manufacturing process that would be required for customizable NiTi devices based on patient geometry. In order to fulfil the potential of the patient-specific superelastic stents, process and design know-how should be expanded to the novel material and fine details at the limits of conventional LPBF machines. In this work, a framework for developing a patient-specific superelastic NiTi stent produced by LPBF is demonstrated. At a proof-of-concept stage, the design procedures are shown in a geometry similar to the artery. The stents with 100 µm nominal strut diameter are later produced with a Ni50.8Ti49.2 powder and heat treated. The results confirm the possibility of producing stents with a design suitable for highly complex patient-specific anatomies and having superelastic behavior at body temperature

Boosting Biomass Quantity and Quality by Improved Mixotrophic Culture of the Diatom Phaeodactylum tricornutum

Diatoms are photoautotrophic unicellular algae and are among the most abundant, adaptable, and diverse marine phytoplankton. They are extremely interesting not only for their ecological role but also as potential feedstocks for sustainable biofuels and high-value commodities such as omega fatty acids, because of their capacity to accumulate lipids. However, the cultivation of microalgae on an industrial scale requires higher cell densities and lipid accumulation than those found in nature to make the process economically viable. One of the known ways to induce lipid accumulation in Phaeodactylum tricornutum is nitrogen deprivation, which comes at the expense of growth inhibition and lower cell density. Thus, alternative ways need to be explored to enhance the lipid production as well as biomass density to make them sustainable at industrial scale. In this study, we have used experimental and metabolic modeling approaches to optimize the media composition, in terms of elemental composition, organic and inorganic carbon sources, and light intensity, that boost both biomass quality and quantity of P. tricornutum. Eventually, the optimized conditions were scaled-up to 2 L photobioreactors, where a better system control (temperature, pH, light, aeration/mixing) allowed a further improvement of the biomass capacity of P. tricornutum to 12 g/L

Fundamental properties of small core holey fibres

We explore some of the fundamental limits in small core silica holey fibres that have a direct bearing on nonlinear device applications. In particular, we examine issues related to coupling and polarization in these fibres

Clinical outcomes under hydroxyurea treatment in polycythemia vera: a systematic review and meta-analysis

Hydroxyurea is the standard treatment in high risk patients with polycythemia vera. Yet, estimates of its effect in terms of clinical outcomes (thrombosis, bleeding, hematological transformations and mortality) are lacking. We performed a meta-analysis to determine the absolute risk of events in contemporary patients under hydroxyurea treatment. We searched for relevant articles or abstracts in the following databases: Medline, EMBASE, clinicaltrials.gov, WHO International Clinical Trials Registry, LILACS. Sixteen studies published from 2008 to 2018 reporting number of events using WHO diagnosis for polycythemia vera were selected. Through a random effect logistic model, incidences, study heterogeneity and confounder effects were estimated for each outcome at different follow-ups. Overall, 3,236 patients were analyzed. While incidences of thrombosis and acute myeloid leukemia were stable over time, mortality and myelofibrosis varied depending on follow-up duration. Thrombosis rates were 1.9, 3.6 and 6.8% persons/year at median ages 60, 70 and 80 respectively. Higher incidence of arterial events was predicted by previous cardiovascular complication. Leukemic transformation incidence was 0.4% persons/year. Incidence of transformation to myelofibrosis and mortality were significantly dependent on age and follow-up duration. For myelofibrosis, rates were 5.0 at 5 year and 33.7% at 10 years; overall mortality was 12.6% and 56.2% at 5 and 10 years respectively. In conclusion, we provide reliable risk estimates for the main outcomes in polycythemia vera patients under hydroxyurea treatment. These findings can help design comparative clinical trials with new cytoreductive drugs and prove the feasibility of using hard endpoints for efficacy, such as major thrombosis

Percutaneous tibial nerve stimulation (PTNS) efficacy in the treatment of lower urinary tract dysfunctions. A systematic review

Background: Percutaneous Tibial Nerve Stimulation (PTNS) has been proposed for the treatment of overactive bladder syndrome (OAB), non-obstructive urinary retention (NOUR), neurogenic bladder, paediatric voiding dysfunction and chronic pelvic pain/painful bladder syndrome (CPP/PBS). Despite a number of publications produced in the last ten years, the role of PTNS in urinary tract dysfunctions remains unclear. A systematic review of the papers on PTNS has been performed with the aim to better clarify potentialities and limits of this technique in the treatment of OAB syndrome and in other above mentioned urological conditions. Methods. A literature search using MEDLINE and ISI web was performed. Search terms used were "tibial nerve" and each of the already mentioned conditions, with no time limits. An evaluation of level of evidence for each paper was performed. Results: PTNS was found to be effective in 37-100% of patients with OAB, in 41-100% of patients with NOUR and in up to 100% of patients with CPP/PBS, children with OAB/dysfunctional voiding and patients with neurogenic pathologies. No major complications have been reported.Randomized controlled trials are available only for OAB (4 studies) and CPP/PBS (2 studies). Level 1 evidence of PTNS efficacy for OAB is available. Promising results, to be confirmed by randomized controlled studies, have been obtained in the remaining indications considered. Conclusions: PTNS is an effective and safe option to treat OAB patients. Further studies are needed to assess the role of PTNS in the remaining indications and to evaluate the long term durability of the treatment. Further research is needed to address several unanswered questions about PTNS

Hydroxyurea prevents arterial and late venous thrombotic recurrences in patients with myeloproliferative neoplasms but fails in the splanchnic venous district. Pooled analysis of 1500 cases

We collected 1500 patients with myeloproliferative neoplasms (MPN) and arterial or venous thrombosis (935/565), pooling three independent cohorts previously reported. Long-term treatment with antiplatelet drugs or vitamin K-antagonists (VKA) was given to 1391 (92.7%) patients; 975 (65%) patients received hydroxyurea (HU). We recorded 348 recurrences (venous in 142 cases) over 6075 patient-years, with an incidence rate of 5.7 per 100 pt-years (95% CI 5.1-6.4). The site of the first thrombosis predicted the site of recurrence. Independent factors influencing the rate of novel arterial thrombosis were HU (HR 0.67, 95% CI 0.46-0.98), antiplatelet treatment (HR 0.54, 95% CI 0.35-0.82), and VKA (HR 0.58, 95% CI 0.35-0.96). On the contrary, the recurrence of venous thromboses was significantly diminished only by VKA (HR 0.60, 95% CI 0.37-0.95), while HU prevented late but not early recurrences after venous thrombosis at common sites. Of note, we failed to demonstrate a positive effect of HU in the prevention of recurrent splanchnic vein thrombosis. In conclusion, in MPN patients, HU plays a role in the prevention of arterial thrombosis, together with aspirin and VKA, whereas its action in the prevention of recurrent venous thrombosis is uncertain. Such findings call for future studies to optimize and personalize secondary prophylaxis after MPN-related thrombosis

Immunohistochemical diagnosis of canine ovarian epithelial and granulosa cell tumors

In humans and canines, the morphology of granulosa cell tumors is extremely variable and causes diagnostic difficulties. In human pathology, immunohistochemistry has been widely used for the diagnosis of granulosa cell tumors, whereas, limited studies are present in canine species. The aim of this study was to investigate the expression of cytokeratins, vimentin, and inhibin-\u3b1 in canine normal ovaries, epithelial ovarian tumors, and granulosa cell tumors to establish an immunohistochemical panel for the differential diagnosis of ovarian tumors. Formalin-fixed, paraffin-embedded tissue sections from 4 normal ovaries, 8 granulosa cell tumors, and 6 epithelial ovarian tumors (2 adenomas and 4 adenocarcinomas) sections were obtained and stained with hematoxylin and eosin and immunohistochemically for cytokeratin AE1/AE3, cytokeratin 7, vimentin, and inhibin-\u3b1. In normal ovaries, cytokeratin 7, cytokeratin AE1/AE3, and vimentin were expressed in the surface epithelium. Granulosa cells were negative for cytokeratin 7 and displayed variable expression of vimentin, cytokeratin AE1/AE3, and inhibin-\u3b1 toward follicular maturation. Granulosa cell tumors were negative for cytokeratin 7 and positive for inhibin-\u3b1. Conversely, ovarian epithelial cells tumors were positive for cytokeratin 7 and negative for inhibin-\u3b1. Both granulosa and epithelial cell tumors displayed variable expression of vimentin. Cytokeratin AE1/AE3 was expressed by all epithelial-derived tumors and 6 of 8 granulosa cell tumors. The results of this study suggest that useful immunohistochemical markers to distinguish epithelial ovarian tumors from granulosa cell tumors are cytokeratin 7 and inhibin-\u3b1

SOHO (SOlid HOley) fiber

We report the first successful fabrication of an all-solid microstructured fiber based on large index contrast glasses. High effective nonlinearity 230 W at 1550nm has been predicted and measured

An ultra-compact particle size analyser using a CMOS image sensor and machine learning

Light scattering is a fundamental property that can be exploited to create essential devices such as particle analysers. The most common particle size analyser relies on measuring the angle-dependent diffracted light from a sample illuminated by a laser beam. Compared to other non-light-based counterparts, such a laser diffraction scheme offers precision, but it does so at the expense of size, complexity and cost. In this paper, we introduce the concept of a new particle size analyser in a collimated beam configuration using a consumer electronic camera and machine learning. The key novelty is a small form factor angular spatial filter that allows for the collection of light scattered by the particles up to predefined discrete angles. The filter is combined with a light-emitting diode and a complementary metal-oxide-semiconductor image sensor array to acquire angularly resolved scattering images. From these images, a machine learning model predicts the volume median diameter of the particles. To validate the proposed device, glass beads with diameters ranging from 13 to 125 µm were measured in suspension at several concentrations. We were able to correct for multiple scattering effects and predict the particle size with mean absolute percentage errors of 5.09% and 2.5% for the cases without and with concentration as an input parameter, respectively. When only spherical particles were analysed, the former error was significantly reduced (0.72%). Given that it is compact (on the order of ten cm) and built with low-cost consumer electronics, the newly designed particle size analyser has significant potential for use outside a standard laboratory, for example, in online and in-line industrial process monitoring