bluuebunny/crossref_metadata_2025 huggingface dataset:
Sulfolane degrading bacteria from petrochemical plant: activated sludge enrichment, isolation and characterization
Authors: Wang Chun-Chin , Liang Chih-Ming , Liu Yi-Hong , Yang Chu-Fang
Published: February 2023

Sulfolane is extensively used as an extractive solvent in sour-gas processing plants in the petrochemical industry. After repeated use, deteriorated sulfolane becomes corrosive and may leak into the environment to threaten aquatic and terrestrial organisms or cause shock loading of wastewater treatment systems. It is therefore important to remove sulfolane from the environment and maintain stable wastewater treatment efficiency. To address this issue, bioaugmentation provides a solution by adding specific microorganisms into the biological treatment system to speed up the contaminant degradation rate. Isolation of microbes capable of degrading target contaminant is key point. Understanding the physiological characteristics of isolated microbes is indispensable for subsequent successful applications. In this study, sulfolane degrading bacteria from the activated sludge of a petrochemical plant were enriched using 200–1000 mg L−1 sulfolane and then isolated. After confirming their sulfolane degrading ability, sulfolane biodegradation was then investigated under various pHs, sulfolane and sulfate concentrations. Enrichment could enhance the sulfolane degrading rate of the mixed culture from 3.9 to 7.1 times. Three strains (strain Y-a, Y-d and Y-f) capable of degrading sulfolane were isolated. The degrading microbes were identified as Cupriavidus sp. using 16S rDNA sequencing. Sulfolane concentration biodegraded by strain Cupriavidus sp. Y-d at pH of 7–9 was 1.40–1.45 times higher than that at pH of 6. The optimal pH for strain Cupriavidus sp. Y-d to degrade sulfolane was 8. When increasing the sulfolane concentration from 500 to 2000 mg L−1, the specific growth rate and specific substrate utilization rate increased from 0.19 to 0.48 d−1 and 0.48 to 0.59 d−1, respectively. Strain Cupriavidus sp. Y-d was capable of degrading 2000 mg L−1 sulfolane. Sulfate concentrations higher than 2511 mg L−1 had a negative effect on sulfolane biodegradation.
Phase II Study Investigating the Safety and Efficacy of Savolitinib and Durvalumab in Metastatic Papillary Renal Cancer (CALYPSO)
Authors: Suárez Cristina , Larkin James M.G. , Patel Poulam , Valderrama Begoña P. , Rodriguez-Vida Alejo , Glen Hilary , Thistlethwaite Fiona , Ralph Christy , Srinivasan Gopalakrishnan , Mendez-Vidal Maria Jose , Hartmaier Ryan , Markovets Aleksandra , Prendergast Aaron , Szabados Bernadett , Mousa Kelly , Powles Thomas
Published: February 2023

PURPOSE

Metastatic papillary renal cancer (PRC) has poor outcomes, and new treatments are required. There is a strong rationale for investigating mesenchymal epithelial transition receptor (MET) and programmed cell death ligand-1 (PD-L1) inhibition in this disease. In this study, the combination of savolitinib (MET inhibitor) and durvalumab (PD-L1 inhibitor) is investigated.

METHODS

This single-arm phase II trial explored durvalumab (1,500 mg once every four weeks) and savolitinib (600 mg once daily; ClinicalTrials.gov identifier: NCT02819596 ). Treatment-naïve or previously treated patients with metastatic PRC were included. A confirmed response rate (cRR) of > 50% was the primary end point. Progression-free survival, tolerability, and overall survival were secondary end points. Biomarkers were explored from archived tissue (MET-driven status).

RESULTS

Forty-one patients treated with advanced PRC were enrolled into this study and received at least one dose of study treatment. The majority of patients had Heng intermediate risk score (n = 26 [63%]). The cRR was 29% (n = 12; 95% CI, 16 to 46), and the trial therefore missed the primary end point. The cRR increased to 53% (95% CI, 28 to 77) in MET-driven patients (n/N = 9/27) and was 33% (95% CI, 17 to 54) in PD-L1–positive tumors (n/N = 9/27). The median progression-free survival was 4.9 months (95% CI, 2.5 to 10.0) in the treated population and 12.0 months (95% CI, 2.9 to 19.4) in MET-driven patients. The median overall survival was 14.1 months (95% CI, 7.3 to 30.7) in the treated population and 27.4 months (95% CI, 9.3 to not reached [NR]) in MET-driven patients. Grade 3 and above treatment related adverse events occurred in 17 (41%) patients. There was 1 grade 5 treatment-related adverse event (cerebral infarction).

CONCLUSION

The combination of savolitinib and durvalumab was tolerable and associated with high cRRs in the exploratory MET-driven subset.
Therapy for Stage IV Non–Small-Cell Lung Cancer With Driver Alterations: ASCO Living Guideline, Version 2022.3
Authors: Jaiyesimi Ishmael A. , Owen Dwight H. , Ismaila Nofisat , Blanchard Elizabeth , Celano Paul , Florez Narjust , Jain Dharamvir , Singh Navneet
Published: February 2023

Living guidelines are developed for selected topic areas with rapidly evolving evidence that drives frequent change in clinical practice. Living guidelines are updated on a regular schedule by a standing expert panel that systematically reviews the health literature on a continuous basis; as described in the ASCO Guidelines Methodology Manual . ASCO Living Guidelines follow the ASCO Conflict of Interest Policy Implementation for Clinical Practice Guidelines . Living Guidelines and updates are not intended to substitute for independent professional judgment of the treating provider and do not account for individual variation among patients. See appendix for disclaimers and other important information ( Appendix 1 and Appendix 2 ). Updates are published regularly and can be found at https://ascopubs.org/nsclc-da-living-guideline .
Long-term Outcome of Body Composition, Ectopic Lipid, and Insulin Resistance Changes With Surgical Treatment of Acromegaly
Authors: Kuker Adriana P , Shen Wei , Jin Zhezhen , Chen Jun , Bruce Jeffrey N , Freda Pamela U
Published: February 2023

Context

Acromegaly presents a unique pattern of lower adiposity and insulin resistance in active disease but reduction in insulin resistance despite a rise in adiposity after surgery. Depot-specific adipose tissue masses and ectopic lipid are important predictors of insulin resistance in other populations, but whether they are in acromegaly is unknown. Long-term persistence of body composition changes after surgery is unknown.

Objective

To determine how depot-specific body composition and ectopic lipid relate to insulin resistance in active acromegaly and whether their changes with surgery are sustained long-term.

Methods

Cross-sectional study in patients with active acromegaly and longitudinal study in newly diagnosed patients studied before and in long-term follow-up, 3 (1-8) years (median, range), after surgery. Seventy-one patients with active acromegaly studied cross-sectionally and 28 with newly diagnosed acromegaly studied longitudinally. Main outcome measures were visceral (VAT), subcutaneous (SAT), and intermuscular adipose tissue masses by whole-body magnetic resonance imaging; intrahepatic lipid (IHL) by proton magnetic resonance spectroscopy; insulin resistance measures derived from fasting; and oral glucose tolerance test insulin and glucose levels.

Results

SAT and insulin-like growth factor 1 level, but not VAT or IHL, were independent predictors of insulin resistance in active acromegaly. VAT, SAT, and IHL gains were sustained long-term after surgery. VAT mass rise with surgery correlated inversely with rise in QUICKI while SAT rise correlated with fall in the Homeostatic Model Assessment score.

Conclusion

SAT and disease activity are important predictors of insulin resistance in active acromegaly. Adiposity gains are sustained long-term after surgical treatment and impact on the accompanying improvement in insulin resistance.
Strolling in the Ruins
Authors: Smith Faith
Published: February 2023

In Strolling in the Ruins Faith Smith engages with a period in the history of the Anglophone Caribbean often overlooked as nondescript, quiet, and embarrassingly pro-imperial within the larger narrative of Jamaican and Trinidadian nationalism. Between the 1865 Morant Bay Rebellion and World War I, British imperialism was taken for granted among both elites and ordinary people, while nationalist discourses would not begin to shape political imagination in the West Indies for decades. Smith argues that this moment, far from being uneventful, disrupts the inevitability of nationhood in the mid-twentieth century and anticipates the Caribbean’s present-day relationship to global power. Smith assembles and analyzes a diverse set of texts, from Carnival songs, poems, and novels to newspapers, photographs, and gardens, to examine theoretical and literary-historiographic questions concerning time and temporality, empire and diaspora, immigration and indigeneity, gender and the politics of desire, Africa’s place within Caribbeanist discourse, and the idea of the Caribbean itself. Closely examining these cultural expressions of apparent quiescence, Smith locates the quiet violence of colonial rule and the insistence of colonial subjects on making meaningful lives.
A Multicenter Allelic Analysis of Diffuse Idiopathic Skeletal Hyperostosis: Nature Versus Nurture?
Authors: Zervos Thomas M. , Jago Silvienne Sint , Erwood Matthew S. , Basheer Azam , Lee Ian Y. , Lubin Farah D. , Schultz Lonni , Walters Beverly C.
Published: February 2023

BACKGROUND:

Diffuse idiopathic skeletal hyperostosis (DISH) is an incompletely defined disease process with no known unifying pathophysiological mechanism.

OBJECTIVE:

To our knowledge, no genetic studies have been performed in a North American population. To summarize genetic findings from previous studies and to comprehensively test for these associations in a novel and diverse, multi-institutional population.

METHODS:

Cross-sectional, single nucleotide polymorphism (SNP) analysis was performed in 55 of 121 enrolled patients with DISH. Baseline demographic data were available on 100 patients. Based on allele selection from previous studies and related disease conditions, sequencing was performed on COL11A2, COL6A6, fibroblast growth factor 2 gene, LEMD3, TGFB1, and TLR1 genes and compared with global haplotype rates.

RESULTS:

Consistent with previous studies, older age (mean 71 years), male sex predominance (80%), a high frequency of type 2 diabetes (54%), and renal disease (17%) were observed. Unique findings included high rates of tobacco use (11% currently smoking, 55% former smoker), a higher predominance of cervical DISH (70%) relative to other locations (30%), and an especially high rate of type 2 diabetes in patients with DISH and ossification of the posterior longitudinal ligament (100%) relative to DISH alone (100% vs 47%, P < .001). Compared with global allele rates, we found higher rates of SNPs in 5 of 9 tested genes (P < .05).

CONCLUSION:

We identified 5 SNPs in patients with DISH that occurred more frequently than a global reference. We also identified novel environmental associations. We hypothesize that DISH represents a heterogeneous condition with both multiple genetic and environmental influences.
Radiologists’ performance in reading digital breast tomosynthesis with and without synthesized views for cancer detection
Authors: Trieu Phuong Dung (Yun) , Noakes Jennie , Li Tong , Borecky Natacha , Brennan Patrick C , Barron Melissa L , Lewis Sarah J
Published: February 2023

Objective:

The study aims to evaluate the diagnostic efficacy of radiologists and radiology trainees in digital breast tomosynthesis (DBT) alone vs DBT plus synthesized view (SV) for an understanding of the adequacy of DBT images to identify cancer lesions.

Methods:

Fifty-five observers (30 radiologists and 25 radiology trainees) participated in reading a set of 35 cases (15 cancer) with 28 readers reading DBT and 27 readers reading DBT plus SV. Two groups of readers had similar experience in interpreting mammograms. The performances of participants in each reading mode were compared with the ground truth and calculated in term of specificity, sensitivity, and ROC AUC. The cancer detection rate in various levels of breast density, lesion types and lesion sizes between ‘DBT’ and ‘DBT + SV’ were also analyzed. The difference in diagnostic accuracy of readers between two reading modes was assessed using Man–Whitney U test. p < 0.05 indicated a significant result.

Results:

There was no significant difference in specificity (0.67-vs-0.65; p = 0.69), sensitivity (0.77-vs-0.71; p = 0.09), ROC AUC (0.77-vs-0.73; p = 0.19) of radiologists reading DBT plus SV compared with radiologists reading DBT. Similar result was found in radiology trainees with no significant difference in specificity (0.70-vs-0.63; p = 0.29), sensitivity (0.44-vs-0.55; p = 0.19), ROC AUC (0.59-vs-0.62; p = 0.60) between two reading modes. Radiologists and trainees obtained similar results in two reading modes for cancer detection rate with different levels of breast density, cancer types and sizes of lesions (p > 0.05).

Conclusion:

Findings show that the diagnostic performances of radiologists and radiology trainees in DBT alone and DBT plus SV were equivalent in identifying cancer and normal cases.

Advances in knowledge:

DBT alone had equivalent diagnostic accuracy as DBT plus SV which could imply the consideration of using DBT as a sole modality without SV.
Stereotactic radiation therapy for oligometastatic esophagogastric adenocarcinoma: outcome and prognostic factors
Authors: Franceschini Davide , Teriaca Maria Ausilia , Di Cristina Luciana , Vernier Veronica , Lo Faro Lorenzo , Franzese Ciro , Comito Tiziana , Clerici Elena , Bellu Luisa , Dominici Luca , Spoto Ruggero , Massaro Maria , Navarria Piera , Scorsetti Marta
Published: February 2023

Objective:

The aim of this study was to evaluate clinical results and prognostic factors in a cohort of patient with oligometastatic esophagogastric adenocarcinoma treated with stereotactic radiation therapy (SRT).

Methods:

This retrospective study included patients affected by 1–3 metastases treated with SRT from 2013 to 2021. Local control (LC), overall survival (OS), progression-free survival (PFS), time to polymetastatic dissemination (TTPD) and time to systemic therapy change/initiation (TTS) were evaluated.

Results:

Between 2013 and 2021, 55 patients were treated with SRT on 80 oligometastatic sites. Median follow-up was 20 months. Nine patients had local progression. 1 and 3 years LC was respectively 92 and 78%. 41 patients experienced further distant disease progression, median PFS was 9.6 months, 1 and 3 years PFS was respectively 40 and 15%. 34 patients died, median OS was 26.6 months, 1 and 3 years OS was respectively 78 and 40%. During follow-up, 24 patients changed or initiated a new systemic therapy; median TTS time was 9 months. 27 patients experienced poliprogression, 44% after 1 year and 52% after 3 years. Median TTPD was 8 months. The best local response (LR), tyming of metastases and PS were related with prolonged PFS on multivariate analysis. LR was correlated with OS at multivariate analysis.

Conclusion:

SRT represents a valid treatment for oligometastatic esophagogastric adenocarcinoma. CR correlated with PFS and OS, while metachronous metastasis and a good PS correlated with a better PFS.

Advances in knowledge:

In selected gastroesopagheal oligometastatic patients, SRT can prolong OS Local response to SRT, metachronous timing of metastases and better PS improve PFS. Local response correlates with OS.
Εκτίμηση υπερηχογραφικών δεικτών καρδιακής λειτουργίας σε ασθενείς με σηπτική καταπληξία
Authors: Σπαθούλας Κωνσταντίνος
Published: February 2023

Εισαγωγή: Ο ρόλος της υπερηχοκαρδιογραφίας στη σηπτική καταπληξία παραμένει αμφιλεγόμενος, καθώς η καταστολή του καρδιακού μεταφορτίου, λόγω ελαττωμένων περιφερικών αντιστάσεων, υπερεκτιμά τη συστολική απόδοση της αριστερής κοιλίας (ΑΚ) και αποκρύπτει τη σηπτική μυοκαρδιοπάθεια (ΣΜ). Σκοπός της μελέτης: Η στατιστική συσχέτιση των υπερηχοκαρδιογραφικά μετρούμενων όγκου παλμού και καρδιακής παροχής σε σχέση με τοποθετημένο σύστημα αιμοδυναμικής παρακολούθησης με βάση τη θερμοαραίωση (PiCCO) σε ασθενείς με σηπτική καταπληξία, καθώς και η αναγνώριση πιθανών υποτύπων της σηπτικής μυοκαρδιοπάθειας μελετώντας το τροποποιημένο με βάση το μεταφόρτιο κλάσμα εξώθησης της ΑΚ (LVEF) και το ολοκλήρωμα ταχύτητας- χρόνου στο χώρο εξόδου της ΑΚ (LVOT VTI) για δεδομένες τιμές συστηματικών αγγειακών αντιστάσεων (SVR)Μέθοδοι: Σε αυτή τη μονοκεντρική μελέτη παρατήρησης συμπεριλάβαμε 14 ασθενείς σε μηχανικό αερισμό και σηπτικό σοκ, με τοποθετημένο σύστημα αιμοδυναμικής παρακολούθησης με βάση τη θερμοαραίωση (PiCCO). Παράλληλες και ταυτόχρονες υπερηχοκαρδιογραφικές και επεμβατικές μετρήσεις (71 μετρήσεις συνολικά) ελήφθησαν από την εμφάνιση της σηπτικής καταπληξίας και κάθε 12 ώρες, για συνολικά 60 ώρες ή μέχρι τον θάνατο του ασθενούς.Αποτελέσματα: Ο όγκος παλμού, υπολογιζόμενος από το LVOT VTI, και η καρδιακή παροχή συσχετίστηκαν με στατιστικά σημαντικό τρόπο με τις PiCCO μετρήσεις (r ≥ 0.993, p < 0.001). Το LVEF και το LVOT VTI έδειξαν γραμμική και εκθετικά αντίστροφη συσχέτιση με τις SVR (R2 = 0.183 vs. 0.507 και p < 0.001 vs. p < 0.001, αντίστοιχα). Tο τροποποιημένο με βάση το μεταφόρτιο κλάσμα εξώθησης (LVEF), μπορεί να ορίσει τη βαρύτητα της ΣΜ (ήπια ≥ 90%, 80% ≤ ενδιάμεση < 90% και σοβαρή < 80%). Η ήπια ΣΜ εμφανίζει φυσιολογικό/ υπερ-φυσιολογικό LVEF, φυσιολογικά VTI και SVR. Η ενδιάμεσης βαρύτητας ΣΜ εμφανίζει χαμηλότερο LVEF και SVR, αλλά αυξημένο τελοδιαστολικό όγκο αριστερής κοιλίας (LVEDV), VTI, όγκο παλμού και καρδιακή παροχή, συγκρινόμενη με την ήπια (p<0.05). Η σοβαρή ΣΜ ξεχωρίζει από την ενδιάμεση με σημαντικά χαμηλότερα LVEF, LVEDV, VTI, όγκο παλμού, καρδιακή παροχή και σημαντικά μεγαλύτερες SVR (p<0.05). Το LVEF και το VTI μειώνονται με την πάροδο του χρόνου στην ήπια ΣΜ, το LVEF μειώνεται στην ενδιάμεση ΣΜ, ενώ στη σοβαρή αυξάνονται σταδιακά και τα δυο. Το LVEF και το VTI αποτελούν χρήσιμα εργαλεία στην αναγνώριση της σοβαρής ΣΜ .Το VTI, αλλά όχι και το LVEF, έδειξε σημαντική διαγνωστική ακρίβεια στην αναγνώριση τιμών SVR < 800 dynes•s•cm−5 και SVR > 1500 dynes•s•cm−5. Συμπεράσματα: Η χρήση του υπερήχου καρδιάς επι κλίνης σε ασθενείς ΜΕΘ για τη μέτρηση LVEF, VTI και τις τροποποιημένες για τις αγγειακές αντιστάσεις τιμές αυτών, βοηθά στην αναγνώριση των φαινοτύπων της ΣΜ, το βαθμό της υποκείμενης αγγειοπάρεσης και τις μεταβολές της καρδιακής παροχής στο σηπτικό σοκ.
Clinical immunology
Authors: Beltyukov E.K. , Naumova V.V. , Smolenskaya O.G.
Published: February 2023

Цели: овладение студентами необходимым объемом теоретических и практических знаний по клинической иммунологии, для освоения выпускниками компетенций в соответствии с ФГОС ВО специальности Лечебное дело и ФГОС ВО специальности Стоматология, с целью выполнения трудовых функций, требуемых профессиональным стандартом «Врач-лечебник (врач-терапевт участковый)» и профессиональным стандартом "Врач-стоматолог".  Задачи: 1) Сформировать у студентов теоретическую базу современной иммунологии и аллергологии и понимание патофизиологических механизмов, лежащих в основе иммунопатологии. 2) Ознакомить студентов с основными нозологическими формами иммунопатологических заболеваний, методами иммунодиагностики, современными подходами к лечению. 3) Сформировать практический навык анализа клинической ситуации при подозрении на патологию иммунной системы у человека, формулирования клинического диагноза, разработки планов диагностики и лечения согласно выставленному диагнозу. 4) Ознакомить студентов с методами иммунопрофилактики, иммунореабилитации, работы с населением, направленной на сохранение и повышение уровня здоровья.
Electronic educational resource "Simulator for developing the skill of writing recipes"
Authors: Bogdanov S.I. , Izmozherova N.V. , Shestakova A.A. , Ugryumova E.M.
Published: February 2023

Интерактивный тренажер для лучшего и качественного самостоятельного усвоения студентами медицинского вуза алгоритма действия врача при оформлении рецептов
Organic Semi Obstacle Solved
Authors: Pitcher Graham
Published: February 2023

NANOSTRUCTURED GATE DIELECTRIC BOOSTS ORGANIC TFT STABILITY IN FLEXIBLE ELECTRONICS.
Semi Sales Boom Not Over
Authors: Grylls Bethan
Published: February 2023

LONG TERM INDUSTRY WATCHER MALCOLM PENN MAKES HIS PREDICTIONS ABOUT SEMICONDUCTOR MARKET GROWTH.
Silicon Stowaways
Authors: Edwards Chris
Published: February 2023

Trojans aren’t restricted to the software domain; in some instances, hardware Trojans could even open backdoors in custom silicon.
Pushing the Envelope
Authors: Pitcher Graham
Published: February 2023

The demands of the IoT are pushing wireless MCU developers to create devices with more processing power, a range of connectivity options and ultra low power consumption.
Containing Potential Problems
Authors: Edwards Chris
Published: February 2023

As intelligence heads towards the edge of the IoT, the container concept is gaining in popularity.
Quality Time
Authors: Beck Chris
Published: February 2023

Quality should be front and centre of every manufacturer’s operations, according to a new survey of industrial leaders. However, as Sam Bailey, sales and marketing director of Miele UK tells MM, they must also concern themselves with quality outside of the four walls of their factory
Walking the Tightrope
Authors: Beck Chris
Published: February 2023

With just over six months to go until the UK leaves the European Union, we examine manufacturers’ readiness, and how they are preparing for Brexit
The Perfect Storm
Authors: Beck Chris
Published: February 2023

The recent CO2 shortage is a microcosm of wider issues surrounding national infrastructure - including energy, says Stephen Newman of E.ON. Manufacturers must begin to plan now for a future with increased challenges
Employment Law SOS
Authors: Giltrap Laura
Published: February 2023

This month, our employment law specialists examine the potential impact of the proposed ethnicity pay gap reporting, inconsistent punishment for the same misconduct, and how to deal with reluctant apprentices
Las construcciones suspendidas en la estructura del discurso oral
Authors: Pérez Béjar Víctor
Published: February 2023

En este trabajo presentamos una nueva visión en la caracterización discursiva de las llamadas construcciones suspendidas, estructuras propias de los discursos orales y de máxima inmediatez comunicativa. Más allá de entender su funcionamiento en unos contextos comunicativos determinados como enunciados independientes, profundizamos en la forma de inserción de estas estructuras dentro de la arquitectura del texto y en su relación con unidades superiores del discurso por encima del enunciado, principalmente, el párrafo y la intervención. Para ello, analizamos las diferentes posiciones que ocupan las suspendidas dentro de estas unidades (inicial, intermedia, final e independiente) en diferentes tipos de texto con diverso grado de distancia comunicativa. De este modo, es posible definir funciones en la formación de unidades discursivas superiores y en la progresión textual de los discursos en los que aparecen las suspendidas. Por último, atendemos a la influencia en la caracterización tipológica de los textos que tienen estas construcciones, pues su mero uso afecta a la posición del texto dentro de la escala de inmediatez-distancia comunicativa; las construcciones suspendidas son un fenómeno propio de la oralidad y caracterizan los textos con ciertos rasgos de este medio.
Characteristics of spatial heterodyne spectroscopy for polarization measurement
Authors: Li Siliang , Luo Haiyan , Li Zhiwei , Ding Yi , Wang Qiansheng , Wei Xiong
Published: February 2023

In this paper, a spatial static polarization modulation interference spectrum technique is proposed, which combines polarimetric spectral intensity modulation (PSIM) technology and spatial heterodyne spectroscopy (SHS), and can obtain the total Stokes parameters of the target light simultaneously. Moreover, there are no moving parts or electronically controlled modulation parts. In this paper, the mathematical model of the modulation process and demodulation process of spatial static polarization modulation interference spectroscopy is deduced, a computer simulation is carried out, the principle prototype is developed, and a verification experiment is carried out. Simulation and experimental results show that the combination of PSIM and SHS can achieve high-precision static synchronous measurement of high spectral resolution, high time resolution, and continuous band complete polarization information.
Improving the standard protocol for above-water reflectance measurements: 1. Estimating effective wind speed from angular variation of sunglint
Authors: Goyens Clémence , Ruddick Kevin
Published: February 2023

The standard above-water protocol for measurement of water reflectance uses a measurement of wind speed to estimate the air–water interface reflectance factor and, thus, remove reflected skylight from upwelling radiance. This aerodynamic wind speed measurement may be a poor proxy for the local wave slope distribution in cases such as fetch-limited coastal and inland waters and/or where there are spatial or temporal differences between the wind speed measurement and the location of reflectance measurements. Here, an improved method is proposed, with a focus on sensors mounted on autonomous pan-tilt units and deployed on fixed platforms, replacing the aerodynamic wind speed measurement by optical measurements of angular variation of upwelling radiance. Using radiative transfer simulations, it is shown that the difference between two upwelling (i.e., water plus air–water interface) reflectances acquired at least 10° apart from each other in the solar principal plane is strongly and monotonically related to effective wind speed. The approach shows good performance in twin experiments using radiative transfer simulations. Limitations of the approach are identified, including difficulties for a very high Sun zenith angle (>60∘), very low wind speed (<2ms−1), and, potentially, cases in which nadir-pointing angles are limited by optical perturbations from the viewing platform.
Optical system design of a DMD–SHS combined modulation interference spectrometer
Authors: Wang Qiansheng , Luo Haiyan , Bai Yunfei , Ding Yi , Li Zhiwei , Xiong Wei
Published: February 2023

Digital micromirror device (DMD) and spatial heterodyne spectroscopy (SHS) combined modulation interference spectroscopy (DMD–SHS) introduces a DMD for the secondary modulation of interferometric data to achieve a Hadamard transform. DMD–SHS can improve the performance index of the spectrometer in terms of the SNR, dynamic range, and spectral bandwidth, while retaining the advantages of a conventional SHS. The DMD–SHS optical system is more complex than a traditional SHS, which places more demands on the optical system’s spatial layout and the optical components’ performance. According to the DMD–SHS modulation mechanism, the functions of the main components were analyzed, and their design requirements were determined. Based on the potassium spectra detection, a DMD–SHS experimental device was designed. The potassium lamp and integrating sphere detection experiments demonstrated the detection capability of the DMD–SHS experimental device with a spectral resolution of 0.0327 nm and a spectral range of 763.66∼771.25nm, which thoroughly verified the feasibility of DMD and SHS combined modulation interference spectroscopy.
SNR enhancement with a non-local means image-denoising method for a Φ-OTDR system
Authors: Li Junchan , Wang Yu , Xiao Lin , Liu Xin , Jin Baoquan
Published: February 2023

Orthogonal pulse pairs generated by the polarization beam splitter (PBS) and the polarization maintaining-optical switch (PM-PSW) can effectively suppress the polarization fading in phase-sensitive optical time-domain reflectometry (Φ-OTDR) systems, but the PM-PSW also brings a lot of noise when switching the optical path periodically. Therefore, a non-local means (NLM) image-processing method is proposed to enhance the signal-to-noise ratio (SNR) of a Φ-OTDR system. Compared with the existing traditional noise reduction methods based on the one-dimensional signal, the method makes full use of redundant texture and self-similarity of multidimensional data. The NLM algorithm can obtain the estimated denoising result value of current pixels by the weighted average of pixels with similar neighborhood structures in the Rayleigh temporal-spatial image. To validate the effectiveness of the proposed approach, we have carried out experiments on the actual signals obtained from the Φ-OTDR system. In the experiment, a sinusoidal waveform of 100 Hz is applied at 20.04 km of the optical fiber as a simulated vibration signal. The switching frequency of PM-PSW is set to 30 Hz. The experimental result shows that the SNR of vibration positioning curve is 17.72 dB before denoising. After using the NLM method based on image-processing technology, the SNR reaches 23.39 dB. Experimental results demonstrate that this method is feasible and effective in improving SNR. This will help to realize accurate vibration location and recovery in practical applications.
Optical Bloch modeling of magnetic dipole transitions in a four-state system and its application in ion trapping: tutorial
Authors: Bester S. , Steenkamp C. M.
Published: February 2023

This tutorial covers the derivation of the optical Bloch equations for a four-state atomic system interacting with an electromagnetic field via magnetic dipole transitions. The derivation of the equations is discussed at length and from first principles such that any student or graduate with a basic quantum mechanics background could follow. The tutorial shows numerical simulations of the model under different conditions, rounding off the understanding of the dependencies of the model. Finally, the functionality of the model is shown by fitting the model to experimental data of ytterbium-171 ions undergoing Rabi oscillations.
Associative memory with self-connected nodes
Authors: Gindi Gene R. , Gmitro Arthur F. , Parthasarathy Kannan
Published: February 2023

The discrete-valued neural network proposed by Hopfield requires zero-diagonal terms in the memory matrix so that the net evolves toward a local minimum of an energy function. For a version of this model with bipolar nodes and positive terms along the diagonal, the net evolves so that only updates that lower the energy by a sufficient amount are accepted. For a net programmed as an outer-product associative content-addressable memory with randomly coded memories, the version with nonzero-diagonal elements performs nearly identically to one with zero-diagonal terms. The dropping of the zero-diagonal requirement may be advantageous for optical implementation in that it allows the memory to configure as a cascade of an inner product operation and weighted summation operation and does not require explicit update of the connectivity matrix.
Does a photodetector measure the light intensity or the energy flux?
Authors: Chyba T. H. , Mandel Leonard
Published: February 2023

The question of whether a photodetector responds to the incident light intensity, the incident energy flux, or some other quantity has been de bated from time to time and has also been examined experimentally. We report on new measurements made with a photoemissive vacuum photodiode, in which the photocurrent produced by an incident laser beam was measured as a function of the angle of incidence, so that total internal reflection occurs at the photocathode. It is found that for an incident TE polarized beam the photoelectric current is proportional to the difference between the incident and reflected intensities or energy fluxes but not for an incident TM polarized beam. It, therefore, appears that the detector measures neither intensity nor energy flux for TM polarized light.
Theory of classical and quantized dipole radiators near a phase conjugate mirror
Authors: Bochove Erik J.
Published: February 2023

The interaction of a radiating dipole with a phase conjugate mirror (PCM) is enhanced due to wavefront reversal by the PCM as well as by possible gain. Moreover, decay at two frequencies is predicted when ω
o
= ω
m
and 4(α
r
+ αnr) d/c ≪ 1, where ω
o
= free oscillation frequency of the dipole, ω
m
= pump frequency of PCM (four-wave mixing), α
r
, and α
nr
are the radiative and nonradiative decay rates, respectively, and d is the effective distance to the PCM. Decay at multiple frequencies is predicted when 4(α
r
+ α
nr
) d/c ≳ 1. Locking of decay frequencies to the pump frequency is predicted at a critical pump intensity and at a second critical point the dipole gains energy from the PCM.
Linear theory of boundary preserving regularization of low-level vision problems
Authors: Shulman David , Aloimonos John
Published: February 2023

Many problems in low-level vision are ill-posed in the sense that their solution does not exist, is not unique, or does not depend continuously on the data. Following the ideas of Poggio and Torre1, we approach such problems by using the Tikhonov and Arsenin2 regularization. That means we find the solution that is as consistent as possible with the data and also as smooth as possible. Smoothing the solution tends to blur boundaries and makes it harder to recognize regions where there are sharp changes in real-world variables. We approach this problem by assuming the error (i.e., the amount of inconsistency of the solution with the data) of nearby points is correlated. The error is modeled as a Levy stable (e.g., Gaussian) blur of a white noise signal. We must first deblur this error. The regularization condition we use tries to minimize the deblurred error and also maintain smoothness. Our condition causes the derivatives of the solution to track the derivatives of the data thus preserving discontinuities. We also observe that the usual smoothness condition constrains only the low-order derivatives of the solution. We constrain all the derivatives. Our procedures require us to perform numerical differentiation of the data, a highly unstable operation. In the course of discussing how to deal with this problem, we develop nonlinear filters for edge detection. Much previous work on discontinuous variation can be viewed theoretically in terms of the concepts we introduce.
Optical multiplexing schemes for encoding 2-D pixel fields
Authors: Craig Alan E. , Griffin Richard D. , Lee John N.
Published: February 2023

Functions of two independent variables are often produced by manipulating, e.g., correlating, data fields or sequences. Two commonly encountered examples are the ambiguity function and the Wigner distribution. The amplitudes of such functions may be generated and displayed optically in a 2-D format. Extracting features from this format (e.g., peaks produced by preceding threshold or hard-clip operations) is a time-consuming task when attempted by serial access. Various optical encoding schemes can multiplex the pixel addresses of peak features into a number of parallel outputs or even into a single sequential signal. The nonlinear processing which generates and displays the pixels of interest is accomplished using a 2-D spatial light modulator. Light from these pixels is multiplied row by row by sets of orthogonal codes using an acoustooptic Bragg cell or a fixed mask along with appropriate anamorphic optics. Rows are then summed on a detector array to perform the multiplexing. Subsequent matched filtering of the detector array output identifies the active spatial light modulator sites.
Practical approach to support reduction
Authors: Brames B. J.
Published: February 2023

Knowledge of an object’s support often proves a valuable constraint when one attempts to reconstruct that object from its autocorrelation. Certain discrete object supports, such as Eisenstein’s support, have the property that they are irreducible; as a consequence, the object and its Hermitian conjugate are uniquely determined to within a translation and unimodular constant. If the object support is known, it can be used as a bounding constraint in reconstruction algorithms or sometimes ensure solution uniqueness even when the object support is reducible. However, it is generally the autocorrelation support which is known rather than the object support.
Fabrication and properties of solution-deposited tapers and lenses for integrated optical circuits
Authors: Hewak Daniel W. , Lit John W. Y. , Waterloo U.
Published: February 2023

The formation of thin films from solutions by dip-coating is a well-known method for the fabrication of optical waveguides. We have developed a procedure with which tapers and lenslike regions in a planar waveguide can be obtained by solution deposition. Using a microprocessor controlled dipping arm, substrates are lowered into a commercial SiO2:TiO2 solution and then carefully withdrawn with a predetermined velocity pattern, which varies as a function of substrate position. As the substrate is removed from the solution, the film immobilizes almost instantly. This, along with the fact that the film thickness depends on the lifting speed, allows us to fabricate high-quality waveguides with varying thickness profiles. A single dipping yields a film with thicknesses from 0.05 to 0.15 μm; thus the structures are typically single mode. Multimode waveguides can be made by repeated dippings. We report on the tapered waveguides that have been fabricated and also describe the fabrication and properties of lenslike waveguides, which focus guided rays with an effective gradient produced by the thickness profile.
Linear and nonlinear optics in semiconductor quantum wells
Authors: Chemla Daniel S.
Published: February 2023

No summary of this tutorial or biographical information was available at press time.
Acoustooptic Interaction in biaxial crystals
Authors: Lee Hyuk
Published: February 2023

Acoustooptic interaction in isotropic and uniaxial crystals has been investigated extensively. Specially uniaxial crystals have been used to increase the bandwidth and angular aperture of the acoustooptic device. However, the acoustooptic interaction in biaxial crystals has not been investigated extensively. Many characteristics of the acoustooptic device, such as bandwidth and angular aperture, depend on the phase mismatch of the acoustooptic interaction. The phase mismatch in turn depends on the wave normal structure of the crystal. The wave normal surfaces of biaxial crystals are more complicated than those of uniaxial crystals. Therefore, we can exploit the complexity of biaxial crystals to improve the characteristics of acoustooptic devices. As an example, we can devise an acoustooptic spatial light modulator with both maximized bandwidth and angular aperture which cannot be achieved with a uniaxial crystal.
Nonlinear phenomena in guided-wave optics
Authors: Wright E.W.
Published: February 2023

No summary was available at press time.
SQUID imaging—reconstructing bioelectric current distributions from measurements of their magnetic fields
Authors: Dallas William J.
Published: February 2023

With the development of superconducting quantum interference device (SQUID) detectors for measuring very weak magnetic fields, it has become possible to map those fields generated by electrical activity in humans. New medical diagnostic tools are now emerging using this technology. We describe the historical development of these diagnostic tools. We begin with some experiments which predate the SQUID. Next we give a brief intuitive explanation of SQUID operating principles. We continue the historical descriptions with developments in magnetoencephalography and magnetocardiography. Finally, we move to a newly developing area: SQUID imaging. In SQUID imaging, SQUID measurement and computer processing are combined to provide images of the currents' sources. Analogies to optical imaging systems are shown, and modifications of common characterization tools (PSF and OTF) are presented.
Creating a total flux scale from the spectral irradiance standard
Authors: Ono Yoshihiro , McSparron Donald A.
Published: February 2023

As an alternate method of creating a total flux scale, a method using an integrating sphere with an opening and two baffles and the spectral irradiance standard placed outside the sphere is proposed. Theoretical analysis was made by computer simulation on several models of the above-mentioned integrating sphere whose geometry was not axially symmetric. The window illuminance was analyzed for varying conditions of sphere geometry such as size and location of the baffles, internal source, and wall reflectance, and an optimum geometry was predicted. Based on the results of the theoretical analysis, an integrating sphere of 20-in. diameter was actually built, and measurements were made in varied conditions, and the experimental results were compared with the results of the simulation. The effect of baffles with various sizes and varied location was first tested on relative bases, and the results were in good agreement with the results of the simulation. Second, absolute comparisons were made using four miniature lamps to compare the flux data obtained by this integrating sphere method and the data obtained by goniophotometry. The data of the two methods agreed within 0.5%.
Seeing a moving bar behind a slit: a new depth mechanism based on kinetic occlusion and the order of ocularity
Authors: Shimojo Shinsuke , Silverman Gerald H. , Nakayama Ken
Published: February 2023

When a vertical bar is moved horizontally behind a narrow vertical slit, there is a time lag between the stimuli to the two eyes. At one particular depth, the stimulus offset for one eye coincides with the stimulus onset for the other eye. Simulation of this particular case on a stereo CRT display revealed that the observer sees a seamless motion of a single target at the depth behind the slit, which is consistent with geometry. If the same trajectory of motion is given to each eye but-in the reversed ocular order, the perception is that of two moving targets just behind the slit. This striking asymmetry between the two cases cannot be explained by changes of convergence or stereopsis based on virtual monocular images. Rather, the visual system seems to take into account the natural- world geometry which constrains the relationship between the direction of motion and order of ocularity. Because the eye of origin information is lost relatively early in cortical processing, the integration process of these two types of information must also occur at early cortical levels.
Acoustic perturbations in autocorrelators using pellicle beam splitters
Authors: Bates Harry E. , Bates Harry E.
Published: February 2023

We have studied ultrafast laser pulses with an autocorrelator system using a thin-film pellicle beam splitter to avoid secondary reflections. We observed components of the correlator signal caused by ambient acoustic vibrations rather than true features of the pulse shape. Resonances were observed at a number of frequencies by injecting a known acoustic signal into the vicinity of the beam splitter.
Comparison of optical and digital cross-correlation functions
Authors: Wombwell J. F. , Reeve C. D.
Published: February 2023

A digital waveform synthesizer driven by a BBC microcomputer has been used to generate both the forward and time-reversed signal inputs required for twin Bragg cell space-integrating correlators. The cross-correlation functions of the two signals have also been computed digitally, and the optical and digital correlation are compared. The digital and optical correlation functions are found to be in generally good agreement. Best results are obtained using a nonheterodyning correlator in which the inputs to the Bragg cells are double-sideband large carrier modulations of the signal on an rf carrier. A significant difference is observed between this case and the suppressed carrier case, in which the correlation function is compressed in time by a factor of 2.
Dependence of speckle statistics of SAR images of rough surfaces on temporal cross-section fluctuations
Authors: Tajbakhsh S. , Ouchi K. , Burge R. E.
Published: February 2023

This paper presents a study on the statistical properties of speckle in synthetic aperture radar (SAR) images of rough surfaces that produce random temporal fluctuations in the backscattered field. The autocorrelation and cross-correlation functions of speckle intensity in single-look and multilook imagery are expressed in terms of the SAR system parameters and the temporal autocorrelation function of the backscattered field.
Broadband bidirectional parallel electrooptic space switch
Authors: Healey Peter , Smith David W.
Published: February 2023

The classical optical matrix-vector multiplier, or crossbar, offers a number of obvious advantages over its electronic counterpart when the data transmission rate is very high. However, there are two principal limiting factors in its design, namely, insertion loss and crosstalk. Insertion loss is unavoidable and sets a loss-limited upper bound to the switch dimensions due to the finite optical power budget. More important, the low-contrast ratio of present-day spatial light modulators (SLMs) and wiring crosstalk caused by aberrations in the imaging optics also sets a limit to switch dimensions. Fortunately, this crosstalk limit is dominant in the lower transmission rate systems which are of less interest. This paper examines the relative magnitudes of the loss and crosstalk limit and their effect on switch dimensions and how the switch performance can be improved by tailoring the input and output optical field shapes. It is also shown how the crossbar can be made bidirectional without loss or crosstalk penalty. A bulk-optic 32 × 32 bidirectional crossbar with a transmission rate of 140 Mbit/s is proposed which uses multimode optical fiber inputs and outputs and a twisted-nematic liquid crystal SLM cross-point matrix.
Absorption and refractive index of one wave changed by irradiating with another laser beam of different wavelength in Ce-SBN crystal
Authors: Xu Huaifang , Jin Yuanwang
Published: February 2023

By measuring the absorption we have found that the 6328-Å (10-mW/mm) laser beam can cause the absorptance of the Ce-SBN crystal to decrease ~20 %, but for the 6328-Å light there is almost no change in the absorption.
New optical logic device based on optoelectronics
Authors: Shi Yan , Zha Kai-De , Guo Yi-Li
Published: February 2023

A new type optical logic device—an optical XOR gate and a clocked optical R-S flip-flop—has been successfully demonstrated using light-emitting diodes (LEDs) and photodiodes (PDs).
Power over wide-angle lenses
Authors: Shafer David
Published: February 2023

Until recently, I knew essentially nothing about wide-angle lenses. I now use them as a test case of my approach to optical design: control through understanding. There has been very little written about wide-angle lenses. Of that, the best is by Erhard Glatzel (as always) and Walter Wolche. This paper addresses my attempts to get up to speed with zero experience in the field, by a new and extremely powerful design theory and technique. It combines the best features of Glatzel’s relaxation approach, Hazaz’s modular design ideas, Hoogland's emphasis on fifth-order Petzval curvature, and my own new insight into a curious property of pupil aberrations. This new theory is sort of an international day approach to lens design. It is particularly suited to dealing with wide-angle lenses but also has applications much more diverse than that.
Efficient estimation of the shape of opacities in computed tomography
Authors: Peng Hui , Stark Henry
Published: February 2023

The limited data problem in tomography refers to two situations: (1) the limited angular view problem where the source and/or detectors are prevented from reaching certain angular displacements and (2) the inability to get a full set of meaningful data because of internal opacities in the object being examined. We address the second situation and show how the size and shape of the convex hull of the opaque object can be estimated from a few measurements. Indeed if only the size and shape of the opacity are required, only O(N) operations (one operation is one addition plus one multiplication) are required as opposed to O(N3) for convolution backprojection reconstruction or O(N2 logN) for direct Fourier inversion. Moreover the signal processing operations required to estimate the opacity are much less complicated than those required in image reconstruction.