Modeling, fabrication, and metrology of 3D printed Alvarez lenses prototypes.

In this work, we present the fabrication of two 3D printed plano-freeform prototypes, designed in such a way that, when assembled, an Alvarez lens is formed. The freeform surface of each element was mathematically described using Zernike polynomials and verified by implementing an off-axis null-screen test. Additionally, a characterization by refraction of the assembled lens was performed. Experimental images show the suitability of additive manufacturing engineering for prototyping freeform optics by providing a practical demonstration of the Alvarez lens concept.

Spanish validation of the short version of the racing and crowded thoughts questionnaire (RCTQ-13).

BACKGROUND: The Racing and Crowded Thoughts Questionnaire (RCTQ-13) is the most widely used specific scale for the measurement of racing thoughts, but there is currently no Spanish version that allow the evaluation in Spanish-speaking patients. The objective of this study is to translate, adapt, and validate the RCTQ-13 in a Colombian population with affective disorders. METHODS: The questionnaire was translated and back-translated, and corrections were implemented following a pilot test to improve comprehensibility. We included patients with Bipolar I Disorder and with Major depressive disorder seen in three centers in the city of Medellín, Colombia. We evaluate structural validity with confirmatory factor analysis, internal consistency, and test-retest reliability. Construct validity was also assessed with the comparison between euthymic, maniac, and depressive episodes and the correlation with worry, rumination, and mania scales. Responsiveness was measured 1 month after the first evaluation. Based on item response theory (IRT), we also estimated item difficulty, discrimination, and fit using a generalized partial credit model. RESULTS: Two hundred fifty subjects were included. Confirmatory factor analysis revealed that the three-factor structure of the scale was appropriate. Internal consistency was adequate for the entire scale (Cronbach's alpha = 0.95, 95% CI: 0.94-0.96) and for each factor. Test-retest reliability was good (intraclass correlation coefficient = 0.82, 95%IC: 0.70-0.88). For construct validity, we observed differences between patients with different types of affective episodes, a moderate positive correlation with the Penn State Worry Scale (r = 0.55) and the Ruminative Response Scale (r = 0.42), and a low negative correlation with the Young Mania Rating Scale (r = - 0.10). Responsiveness was proved to be adequate. Under IRT, the response thresholds for the response options are organized for all items. The infit was adequate for all items and the outfit was acceptable. CONCLUSIONS: The Spanish version of the RCTQ-13 is a reliable, valid, and responsive scale and can be used for the clinical assessment of the construct of racing and crowded thoughts in patients with the spectrum of affective disorders in whom this experience can be expressed with different nuances. Further research is needed to expand the relationship with rumination and worry.

Mitochondrial DNA control region typing from highly degraded skeletal remains by single-multiplex next-generation sequencing.

Poor nuclear DNA preservation from highly degraded skeletal remains is the most limiting factor for the genetic identification of individuals. Mitochondrial DNA (mtDNA) typing, and especially of the control region (CR), using next-generation sequencing (NGS), enables retrieval of valuable genetic information in forensic contexts where highly degraded human skeletal remains are the only source of genetic material. Currently, NGS commercial kits can type all mtDNA-CR in fewer steps than the conventional Sanger technique. The PowerSeq CRM Nested System kit (Promega Corporation) employs a nested multiplex-polymerase chain reaction (PCR) strategy to amplify and index all mtDNA-CR in a single reaction. Our study analyzes the success of mtDNA-CR typing of highly degraded human skeletons using the PowerSeq CRM Nested System kit. We used samples from 41 individuals from different time periods to test three protocols (M1, M2, and M3) based on modifications of PCR conditions. To analyze the detected variants, two bioinformatic procedures were compared: an in-house pipeline and the GeneMarker HTS software. The results showed that many samples were not analyzed when the standard protocol (M1) was used. In contrast, the M3 protocol, which includes 35 PCR cycles and longer denaturation and extension steps, successfully recovered the mtDNA-CR from highly degraded skeletal samples. Mixed base profiles and the percentage of damaged reads were both indicators of possible contamination and can provide better results if used together. Furthermore, our freely available in-house pipeline can provide variants concordant with the forensic software.

Biosynthesis of triacsin featuring an N-hydroxytriazene pharmacophore.

Triacsins are an intriguing class of specialized metabolites possessing a conserved N-hydroxytriazene moiety not found in any other known natural products. Triacsins are notable as potent acyl-CoA synthetase inhibitors in lipid metabolism, yet their biosynthesis has remained elusive. Through extensive mutagenesis and biochemical studies, we here report all enzymes required to construct and install the N-hydroxytriazene pharmacophore of triacsins. Two distinct ATP-dependent enzymes were revealed to catalyze the two consecutive N-N bond formation reactions, including a glycine-utilizing, hydrazine-forming enzyme (Tri28) and a nitrite-utilizing, N-nitrosating enzyme (Tri17). This study paves the way for future mechanistic interrogation and biocatalytic application of enzymes for N-N bond formation.

Fabrication of biconvex spherical and aspherical lenses using 3D printing.

In this work, we present the methods of fabrication and characterization of biconvex spherical and aspherical lenses with 25 and 50 mm diameters that have been created via additive technology using a Formlabs Form 3 stereolithography 3D printer. After the prototypes are postprocessed, fabrication errors ≤2.47% for the radius of curvature, the optical power, and the focal length are obtained. We show eye fundus images captured with an indirect ophthalmoscope using the printed biconvex aspherical prototypes, proving the functionality of both the fabricated lenses and the proposed method, which is fast and low-cost.

Mutation in Chek2 triggers von Hippel-Lindau hemangioblastoma growth.

PURPOSE: Von Hippel-Lindau (VHL) is a rare inherited disease mainly characterized by the growth of tumours, predominantly hemangioblastomas (Hbs) in the CNS and retina, and renal carcinomas. The natural history of VHL disease is variable, differing in the age of onset and its penetrance, even among relatives. Unfortunately, sometimes VHL shows more severe than average: the onset starts in adolescence, and surgeries are required almost every year. In these cases, the factor that triggers the appearance and growth of Hbs usually remains unknown, although additional mutations are suspected. METHODS: We present the case of a VHL patient whose first surgery was at 13 years of age. Then, along his next 8 years, he has undergone 5 surgeries for resection of 10 CNS Hbs. To clarify this severe VHL condition, DNA from a CNS Hb and white blood cells (WBC) was sequenced using next-generation sequencing technology. RESULTS: Massive DNA sequencing of the WBC (germ line) revealed a pathogenic mutation in CHEK2 and the complete loss of a VHL allele (both tumour suppressors). Moreover, in the tumour sample, several mutations, in BRAF1 and PTPN11 were found. Familiar segregation studies showed that CHEK2 mutation was in the maternal lineage, while VHL was inherited by paternal lineage. CONCLUSIONS: Finally, clinical history correlated to the different genotypes in the family, concluding that the severity of these VHL manifestations are due to both, VHL-and-CHEK2 mutations. This case report aims to notice the importance of deeper genetic analyses, in inherited rare diseases, to uncover non-expected mutations.

Smartphone-based corneal topography with null-screens.

To measure the shape of the fast corneal surface of the human eye, we propose the design and characterization of a compact corneal topographer using the capabilities of a smartphone. The performance evaluation of the compact corneal topographer includes the calculation and compensation of the distortion introduced by the smartphone lens used to acquire the images and the evaluation of a reference surface. To demonstrate the feasibility of our proposal, we performed surface topography measurements on some human corneas and compared the results with those obtained by a commercial corneal topographer. We showed that the results obtained with our algorithms were consistent with other methods that analyze the corneal surface.

Null-screen testing of the complementary freeform surfaces of an adjustable focus lens.

A novel null-screen technique to test freeform optical surfaces for ophthalmic use is presented. We present an off-axis experimental setup to evaluate the surface shape of a two-element commercial adaptable focus lens based on the Alvarez principle. The advantages of the method are that it is fast, easy to implement, and reduces costs. This metrology technique is validated by testing both the convex and the concave complementary freeform elements of the spectacle under test. We also apply two methods to recover the surface shape of both elements: numerical integration and a custom probabilistic algorithm. Results are compared with a reference surface finding that for method 1, the RMS value in sagitta differences is 32.6 microns for the convex surface and 26.5 microns for the concave surface. Meanwhile, for method 2, the RMS value in sagitta differences found is 19.8 microns for the convex surface and 16.9 microns for the concave surface. Results show agreement in RMS in sagitta differences for both surfaces in each of the reconstruction methods employed.

Predictive models of infection in patients with systemic lupus erythematosus: A systematic literature review.

INTRODUCTION: Having reliable predictive models of prognosis/the risk of infection in systemic lupus erythematosus (SLE) patients would allow this problem to be addressed on an individual basis to study and implement possible preventive or therapeutic interventions. OBJECTIVE: To identify and analyze all predictive models of prognosis/the risk of infection in patients with SLE that exist in medical literature. METHODS: A structured search in PubMed, Embase, and LILACS databases was carried out until May 9, 2020. In addition, a search for abstracts in the American Congress of Rheumatology (ACR) and European League Against Rheumatism (EULAR) annual meetings' archives published over the past eight years was also conducted. Studies on developing, validating or updating predictive prognostic models carried out in patients with SLE, in which the outcome to be predicted is some type of infection, that were generated in any clinical context and with any time horizon were included. There were no restrictions on language, date, or status of the publication. To carry out the systematic review, the CHARMS (Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies) guideline recommendations were followed. The PROBAST tool (A Tool to Assess the Risk of Bias and Applicability of Prediction Model Studies) was used to assess the risk of bias and the applicability of each model. RESULTS: We identified four models of infection prognosis in patients with SLE. Mostly, there were very few events per candidate predictor. In addition, to construct the models, an initial selection was made based on univariate analyses with no contraction of the estimated coefficients being carried out. This suggests that the proposed models have a high probability of overfitting and being optimistic. CONCLUSIONS: To date, very few prognostic models have been published on the infection of SLE patients. These models are very heterogeneous and are rated as having a high risk of bias and methodological weaknesses. Despite the widespread recognition of the frequency and severity of infections in SLE patients, there is no reliable predictive prognostic model that facilitates the study and implementation of personalized preventive or therapeutic measures.Protocol registration number: PROSPERO CRD42020171638.

Null-screen design for highly freeform surface testing.

A new alternative to calculate the null-screen for highly freeform or complex surfaces for any desired pattern to be observed on the detector is presented. To validate the proposed method, we used the Zernike polynomials to design complex surfaces with sagittas greater or equal to 40 mm, and peak to valley greater or equal to 30 mm, between the used surface and the best fit sphere. The freeform surfaces were fabricated using a 3D printer and a five-axis CNC machine. With the proposed method we can calculate the image that will be observed over the detector for any null-screen and any freeform surface that want to be analyzed. The results showed that the proposal works very well for extremely fast complex freeform surfaces (with slopes ≤ 80°), obtaining an error smaller than 0.66% in PV and 0.36% in rms in sagitta differences.

Microscopic and submicroscopic Plasmodium infections in indigenous and non-indigenous communities in Colombia.

BACKGROUND: The indigenous population is considered a highly susceptible group to malaria because individuals usually live in areas with high exposure to Anopheles and poverty, and have limited access to health services. There is a great diversity of indigenous communities in Colombia living in malaria-endemic areas; however, the burden of infection in these populations has not been studied extensively. This study aimed to determine the prevalence of Plasmodium infections in indigenous and non-indigenous communities in two malaria-endemic areas in Colombia. METHODS: A community-based cross-sectional survey was conducted in seven villages of Turbo and El Bagre municipalities; three of these villages were indigenous communities. Inhabitants of all ages willing to participate were included. Sociodemographic and clinical data were recorded as well as household information. The parasitological diagnosis was performed by microscopy and nested PCR. The prevalence of microscopy and submicroscopic infection was estimated. An adjusted GEE model was used to explore risk factors associated with the infection. RESULTS: Among 713 participants, 60.7% were from indigenous communities. Plasmodium spp. was detected in 30 subjects (4.2%, CI 95% 2.9-5.9); from those, 29 were in the indigenous population, 47% of infections were afebrile, and most of them submicroscopic (10/14). Microscopic and submicroscopic prevalence was 2.5% (CI 95% 1.6-3.9) and 1.7% (CI 95% 0.9-2.9), respectively. In El Bagre, all infections occurred in indigenous participants (3.9%, CI 95% 2.2-7.1), and 81% were submicroscopic. By contrast, in Turbo, the highest prevalence occurred in indigenous people (11.5%; CI 95%: 7.3-17.5), but 88.8% were microscopic. Living in an indigenous population increased the prevalence of infection compared with a non-indigenous population (PR 19.4; CI 95% 2.3-166.7). CONCLUSION: There is a high proportion of Plasmodium infection in indigenous communities. A substantial proportion of asymptomatic and submicroscopic carriers were detected. The identification of these infections, not only in indigenous but also in the non-indigenous population, as well as their associated factors, could help to implement specific malaria strategies for each context.

Initial Experience in Chile with Stent Implantation in the Right Ventricle Outflow Tract in High-Risk Patients with Tetralogy of Fallot.

Tetralogy of Fallot (ToF) treatment is difficult in patients with surgical risk factors or unfavorable anatomy. Stent implantation in the right ventricular outflow tract (RVOT) is an option for these patients. We report our initial experience in Chile with RVOT stenting in patients with ToF. Retrospective and descriptive study conducted in three pediatric cardiovascular centers in Chile between 2012 and 2015, including all ToF patients with stent in the RVOT as first procedure. Clinical records, echocardiographic, interventional, and surgical reports were reviewed for demographics and information of RVOT and pulmonary arteries. 12 newborns with ToF were included (75% female). Median age was 20 days (1-70) and mean weight was 2178 g (1400-3414). Saturations increased after the procedure from 74.3% (55-88) to 88.5% (80-98%), (p < 0.01). No complications or mortality were related to interventions. Follow-up was 11 months (7-36). Median right and left pulmonary arteries Z-score increased from - 4.0 (- 5.2 to - 0.3) and - 1.5 (- 4.8 to - 0.26) to + 0.53 (0.0 to 2.2) and + 1.1 (0.5 to 2.9), (p < 0.05), respectively. Nakata index increased from 63 mm2/mm2 (35 to 143) to 162 mm2/mm2 (107 to 197), (p < 0.05). Surgical repair was performed at a median of 4 months (2-7). Transannular patch repair was necessary in all patients and there was no surgical mortality. RVOT stenting is a safe and useful option for patients with ToF and surgical risk factors or unfavorable anatomy. It increases the pulmonary blood flow, improving saturation and pulmonary artery growth as a bridge for surgical repair.

Single trans-septal access technique for left atrial intracardiac echocardiography to guide left atrial appendage closure.

OBJECTIVE: This registry aimed to describe the safety and feasibility of a single trans-septal (TS) access technique for left intracardiac echocardiography (ICE) guidance of left-atrial appendage (LAA) closure procedure. BACKGROUND: LAA closure is currently accepted as an alternative to oral anticoagulation (OAC) in patients with non-valvular atrial fibrillation (NVAF) who are at high-risk for bleeding. Currently, LAA closure procedure is typically performed under trans-esophageal echocardiogram (TEE) guidance. Although, ICE has the advantage of not requiring profound sedation/anesthesia, ICE-LAA imaging quality is often limited from the right atrium requiring double TS access. METHODS: Twenty-two patients with NVAF underwent LAA closure using the Amplatzer Amulet™ device (St Jude Medical) under ICE guidance from the left atrium. The ICE AcuNav catheter (Biosense Webster) and the Amulet delivery sheath were advanced into the LA through single TS puncture technique. RESULTS: The population was predominately male (59.1%) with a mean age of 74 ± 9.3 years, at high-risk for stroke (mean CHADS2 score of 3.8 ± 1.1) and bleeding (mean HAS BLED score of 3.5 ± 1.3). The Amplatzer AmuletTM device was successfully implanted in all patients. No procedural related complications including device embolization were noted. No major cardiovascular events occurred and all patients were discharged alive. At 30-day follow-up all patients remained alive, free of ischemic stroke and with no residual leak or device thrombus on TEE. CONCLUSIONS: This initial experience suggests that LAA occlusion with the Amplatzer Amulet device using ICE guidance from the left atrium via a single trans-septal technique is feasible and safe.

General equations for the null-screen test for aspherical surfaces with deformation coefficients.

A modified approach to calculate the null screen for testing fast convex/concave aspherical surfaces with deformation coefficients is presented. Introducing the aberration polynomial into the equation of the sagitta, the null screens can be generated in a simple way, in contrast to the conventional design method. This approach is easy to implement for the calculation of the null screen since the equations presented here are easy to program computationally. The validation of this approach was done by analyzing the fast aspherical surface of a convex condenser lens (f/0.18). We obtained a percentage error smaller than 1.3% in the recovery of the coefficients that describe the shape of the surface.

Political transition and emergent forest-conservation issues in Myanmar.

Political and economic transitions have had substantial impacts on forest conservation. Where transitions are underway or anticipated, historical precedent and methods for systematically assessing future trends should be used to anticipate likely threats to forest conservation and design appropriate and prescient policy measures to counteract them. Myanmar is transitioning from an authoritarian, centralized state with a highly regulated economy to a more decentralized and economically liberal democracy and is working to end a long-running civil war. With these transitions in mind, we used a horizon-scanning approach to assess the 40 emerging issues most affecting Myanmar's forests, including internal conflict, land-tenure insecurity, large-scale agricultural development, demise of state timber enterprises, shortfalls in government revenue and capacity, and opening of new deforestation frontiers with new roads, mines, and hydroelectric dams. Averting these threats will require, for example, overhauling governance models, building capacity, improving infrastructure- and energy-project planning, and reforming land-tenure and environmental-protection laws. Although challenges to conservation in Myanmar are daunting, the political transition offers an opportunity for conservationists and researchers to help shape a future that enhances Myanmar's social, economic, and environmental potential while learning and applying lessons from other countries. Our approach and results are relevant to other countries undergoing similar transitions.

Recurrent adult-type fibrosarcoma of the frontal bone in a child.

INTRODUCTION: Primary, adult-type bone fibrosarcoma is an uncommon, malignant spindle-cell tumor of fibroblastic origin, rarely affecting children. Most frequently diagnosed among bone malignancies in the past, improved diagnostic techniques and further restrictive classification criteria have currently made the diagnosis of fibrosarcoma very unusual. CASE REPORT: We hereby report the case of a 7-year-old child with a right frontal swelling mass. A computed tomography scan showed an osteolytic lesion of the right frontal bone, involving the diploe and the outer table of the skull. An en bloc surgical excision, followed by a thorough immunohistological evaluation, led to the diagnosis of fibroblastic proliferation, with low cellularity and minimal atypias. The patient had four recurrences during the 4-year follow-up. With an increasing histological grade at recurrences, a diagnosis of adult-type fibrosarcoma was made. CONCLUSION: To the best of the authors' knowledge, this is the first reported case of an adult-type fibrosarcoma arising in the frontal bone of a child.

Use of the amplatzer vascular plug II device to occlude different types of patent ductus arteriosus in pediatric patients.

INTRODUCTION: Transcatheter patent ductus arteriosus (PDA) closure is difficult in small patients in part due to the diverse PDA morphology. We describe a multicenter pediatric experience using the Amplatzer Vascular Plug II device (AVP II) to occlude PDA. METHODS: All patients undergoing transcatheter closure of PDA with AVP II from April 2008 until May 2012 were included. Clinical, angiographic, and echocardiographic data were collected. RESULTS: One hundred and seventy-seven procedures were performed. Median age was 14 months (2-180) with median weight 9.7 kg (4.7-68). The morphological PDA classification was Type A in 66 (37.1%), Type C in 27 (15.3%), Type D in 17 (9.6%), and Type E in 67 (37.9%). The median minimum PDA diameter was 2.6 mm (1.2-7.7 mm). The implanted device sizes were: 4 mm in 17 patients (9.6%), 6 mm in 81 (45.8%), 8 mm in 56 (31.6%), 10 mm in 18 (10.2%), and 12 mm in 5 (2.8%). The implanted device was mean of 2.6 + 0.7 times the ductus narrowest diameter and mean of 1 + 0.5 times the ductus largest diameter. Complications included: one severe left pulmonary artery stenosis and one device embolization. No aortic obstruction occurred. Closure was complete in the 175 remaining patients. CONCLUSIONS: The AVP II is an effective and safe device for PDA closure. It is particularly useful when dealing with nontypical PDA shapes and in small infants where it eliminated the risk of device-related aortic obstruction. The AVPII is an addition to the PDA device closure armamentarium in pediatric patients.

Phase shifting interferometry using a spatial light modulator to measure optical thin films.

This work describes a process for measuring thin film steps, using phase shifting interferometry (PSI). The phase shifts are applied only in the region where the thin film steps are located. The phase shift is achieved by displaying different gray levels on a spatial light modulator (SLM Holoeye LC2012) placed in one arm of a Twyman-Green (T-G) interferometer. Before measuring the thin film steps, it was necessary to quantify the phase shifts achieved with this SLM by measuring the fringe shifts in experimental interferograms. The phase shifts observed in the interference patterns were produced by displaying the different gray levels on the SLM one by one, from 0 to 255. The experimental interferograms and the thicknesses of the thin film steps were successfully quantified, proving that this method can be used to measure thin films by applying the PSI method only on the region occupied by them.

Cerebral sparganosis: case report and review of the European cases.

Sparganosis is a severe parasitic infection caused by the larvae of Spirometra mansoni, also called "sparganum." In human hosts, the Spirometra mansoni larva commonly targets the subcutaneous tissue or muscle. Sometimes it can also migrate into the brain, resulting in cerebral sparganosis, mainly characterized by focal neurological symptoms such as seizures and radiological "wandering lesions" on magnetic resonance images (MRIs). Clinical cases of cerebral sparganosis have been reported worldwide, mainly in Asian countries, but also in North America, South America and Australia. Only two cases have been previously reported in Europe. A 29-year-old male from Bolivia, who lived in Spain, presented to our service for seizures and a multicystic brain lesion, initially suspected to be a dysembryoplastic neuroepithelial tumor (DNET). He underwent gross total resection of the mixed solid/cystic lesion. Pathology revealed gliosis, multiple interconnected cystic cavities with fibrous walls, inflammatory cell infiltration and no necrotizing granulomatous reaction. Inside the cavities, a parasitic form was identified as the larva of the cestode Spirometra mansoni. At 1-year follow-up, the patient had no deficits and was seizure free. Clinicians should be alerted to the possible existence of this rare entity in Europe, especially in patients from endemic areas with a possible infection history as well as "wandering lesions" on the MRI.

Transcatheter closure of perimembranous ventricular septal defect with the Amplatzer(®) membranous VSD occluder 2: initial world experience and one-year follow-up.

OBJECTIVES: To describe the initial world experience and mid-term follow-up of perimembranous ventricular septal defect (pmVSD) closure with a newly designed occluder. BACKGROUND: Transcatheter closure of pmVSDs has been associated with a substantial risk of complete heart block, prompting many centers to abandon this intervention. METHODS: A prospective multicenter cohort study was conducted on patients with pmVSD undergoing catheter closure using the Amplatzer(®) Membranous VSD Occluder 2 in the initial 4 pilot centers. RESULTS: Nineteen patients, median age 6 years (range 1.4-62 years), were enrolled and followed for 14 ± 3 months (range 8-20 months). The median weight was 26 kg (range 9.3-96 kg) and the mean Qp/Qs ratio was 1.8 ± 0.7. The defect on left ventricular side measured 9.9 ± 3.5 mm and the orifice on right ventricular side was 8.1 ± 2.8 mm by echocardiography. Mean device size was 9.4 ± 2.4 mm (range 5-14 mm). An eccentric device was employed in 9 patients (47%) and a concentric device in 10 (53%). Overall, 18 patients (95%) had successful device implants. Procedural time was 122 ± 39 min. There were no procedural complications. Mild residual shunting was initially observed in 14 (78%) patients. At last follow-up, mild residual shunting persisted in only 3 (17%) patients. There was no significant increase in aortic or tricuspid regurgitation. No patient had any degree of AV block, although one developed a transient left anterior fascicular block. Holter evaluation, obtained in all patients, was unremarkable in all. CONCLUSIONS: This early cohort experience using a novel adapted transcatheter closure device for pmVSD suggests that the procedure is feasible, safe, and effective.