bluuebunny/crossref_metadata_2025 huggingface dataset:
A comparative study of parasitic fauna in Amietophrynus regularis (Reuss, 1833) from natural habitats and dumpsites within Lagos Metropolis, Southwest Nigeria
Authors: Okeagu Okechukwu Martin , Akinsanya Bamidele , Uzoka Tolulope
Published: April 2022

Background

Amphibian parasites have been used as models for understanding important issues about host activity and sensitivity to environmental perturbations and amphibian decline. With the aim of comparing the parasitic fauna in Amietophrynus regularis from natural habitat and dumpsites within Lagos metropolis, a total of 172 toads were sampled to determine the occurrence of the gastrointestinal tract and blood parasites.

Methods

The liver, lungs, intestine and intestinal fluids, and blood were collected for parasitological determination. Histopathological analysis was carried out on the intestinal tracts.

Results

Helminths recovered from the gastrointestinal tract belonged to the family Nematoda, and they included Cosmocerca spp., Amplicaecum spp., Strongyloides spp., and oxyurides. Cosmocerca spp. was most abundant with a parasite load of 2304 and a prevalence of 70.93%. Protozoans recovered from the gastrointestinal fluids include Opalina spp. (7.5%) and Balantidium spp. (11.05%). The only protozoan recovered from blood was a species of Hepatozoon. Although parasite intensity was higher in larger females, comparison of parasites prevalence with morphometrics of Amietophrynus regularis was not significant at p = 0.05. There was also no significant difference (p = 0.05) between the parasite abundance and the location of collection. Histopathological findings revealed stunting of the villi with a high level of intestinal tissue alterations in infected Amietophrynus regularis from the natural habitat.

Conclusions

The high levels of parasitic infection together with the histopathological findings are indicative that the natural habitats of Amietophrynus regularis are being perturbed and this is of concern considering the prevailing issues of amphibian decline.
Multi-detector computed tomography and 3Tesla magnetic resonance imaging in assessment of COVID-19 intracranial complications
Authors: Ibrahim Ghada Sobhy , Alkandari Buthaina M. , Elzeneini Ahmed Mahmoud , Shady Islam Ahmed Abo , Housseini Ahmed Mohamed , Abdelmohsen Mohsen Ahmed
Published: April 2022

Background

The novel worldwide coronavirus (COVID-19) pandemic, first appearing in Wuhan, China, has allured immense global attention. To our comprehension, this research work accommodates the largest isolation hospital-conducted cohort of coronavirus patients in which neuro-radiological complications were retrospectively assessed. To the present day, our full understanding of COVID-19 and its spectrum of diverse complications still remains insufficient. Moreover, the number of reported neurological complications albeit the global spread of the coronavirus pandemic is also widely lacking due to the constrained implementation of MR neuro-imaging in COVID-19 patients.

Results

Forty-eight males and 26 females met the inclusion criteria, with a mean age 60.55 (ranged from 22 to 88 years old). The frequent clinical manifestation has impaired level of consciousness 55.4%. Most commonly recurring radiological findings were ischemic stroke 54.06% and parenchymal hematomas and hemorrhage 25.69%. Other less imaging brain findings were certain diagnostic entities, i.e., PRES, cerebral edema, leuko-encephalopathic WM abnormalities, microhemorrhages, vascular thrombosis and acute necrotizing encephalopathy. Soaring mortality rates correlated with serious neuro-radiological manifestations, being highest with infarction 57.5%, p = 0.908 and hemorrhage/hematomas 63.2%, p = 0.604.

Conclusions

Intra-cranial complications were significantly detectable in COVID-19 infection and correlated with severity of illness. Outstanding higher mortality rates were associated with worsening neuro-radiological complications.
Mailed fecal testing and patient navigation versus usual care to improve rates of colorectal cancer screening and follow-up colonoscopy in rural Medicaid enrollees: a cluster-randomized controlled trial
Authors: Coronado Gloria D. , Leo Michael C. , Ramsey Katrina , Coury Jennifer , Petrik Amanda F. , Patzel Mary , Kenzie Erin S. , Thompson Jamie H. , Brodt Erik , Mummadi Raj , Elder Nancy , Davis Melinda M.
Published: April 2022

Background

Screening reduces incidence and mortality from colorectal cancer (CRC), yet US screening rates are low, particularly among Medicaid enrollees in rural communities. We describe a two-phase project, SMARTER CRC, designed to achieve the National Cancer Institute Cancer MoonshotSM objectives by reducing the burden of CRC on the US population. Specifically, SMARTER CRC aims to test the implementation, effectiveness, and maintenance of a mailed fecal test and patient navigation program to improve rates of CRC screening, follow-up colonoscopy, and referral to care in clinics serving rural Medicaid enrollees.

Methods

Phase I activities in SMARTER CRC include a two-arm cluster-randomized controlled trial of a mailed fecal test and patient navigation program involving three Medicaid health plans and 30 rural primary care practices in Oregon and Idaho; the implementation of the program is supported by training and practice facilitation. Participating clinic units were randomized 1:1 into the intervention or usual care. The intervention combines (1) mailed fecal testing outreach supported by clinics, health plans, and vendors and (2) patient navigation for colonoscopy following an abnormal fecal test result. We will evaluate the effectiveness, implementation, and maintenance of the intervention and track adaptations to the intervention and to implementation strategies, using quantitative and qualitative methods. Our primary effectiveness outcome is receipt of any CRC screening within 6 months of enrollee identification. Our primary implementation outcome is health plan- and clinic-level rates of program delivery, by component (mailed FIT and patient navigation). Trial results will inform phase II activities to scale up the program through partnerships with health plans, primary care clinics, and regional and national organizations that serve rural primary care clinics; scale-up will include webinars, train-the-trainer workshops, and collaborative learning activities.

Discussion

This study will test the implementation, effectiveness, and scale-up of a multi-component mailed fecal testing and patient navigation program to improve CRC screening rates in rural Medicaid enrollees. Our findings may inform approaches for adapting and scaling evidence-based approaches to promote CRC screening participation in underserved populations and settings.

Trial registration

Registered at clinicaltrial.gov (NCT04890054) and at the NCI’s Clinical Trials Reporting Program (CTRP #: NCI-2021-01032) on May 11, 2021.
Circulating Tumor-Macrophage Fusion Cells and Circulating Tumor Cells Complement Non–Small-Cell Lung Cancer Screening in Patients With Suspicious Lung-RADS 4 Nodules
Authors: Manjunath Yariswamy , Suvilesh Kanve Nagaraj , Mitchem Jonathan B. , Avella Patino Diego M. , Kimchi Eric T. , Staveley-O'Carroll Kevin F. , Pantel Klaus , Yi Huang , Li Guangfu , Harris Peter K. , Chaudhuri Aadel A. , Kaifi Jussuf T.
Published: April 2022

PURPOSE

Low-dose computed tomography (LDCT) screening of high-risk patients decreases lung cancer–related mortality. However, high false-positive rates associated with LDCT result in unnecessary interventions. To distinguish non–small-cell lung cancer (NSCLC) from benign nodules, in the present study, we integrated cellular liquid biomarkers in patients with suspicious lung nodules (lung cancer screening reporting and data system [Lung-RADS] 4).

METHODS

Prospectively, 7.5 mL of blood was collected from 221 individuals (training set: 90 nonscreened NSCLC patients, 74 high-risk screening patients with no/benign nodules [Lung-RADS 1-3], and 20 never smokers; validation set: 37 patients with suspicious nodules [Lung-RADS 4]). Circulating tumor cells (CTCs), CTC clusters, and tumor-macrophage fusion (TMF) cells were identified by blinded analyses. Screening patients underwent a median of two LDCTs (range, 1-4) with a median surveillance time of 30 (range, 11-50) months.

RESULTS

In the validation set of 37 Lung-RADS 4 patients, all circulating cellular biomarker counts ( P < .005; Wilcoxon test) and positivity rates were significantly higher in 23 biopsy-proven NSCLC patients (CTCs: 23 of 23 [100%], CTC clusters: 6 of 23 [26.1%], and TMF cells: 15 of 23 [65.2%]) than in 14 patients with biopsy-proven benign nodules (6 of 14 [42.9%], 0 of 14 [0%], and 2 of 14 [14.3%]). On the basis of cutoff values from the training set, logistic regression with receiver operating characteristic and area under the curve analyses demonstrated that CTCs (sensitivity: 0.870, specificity: 1.0, and area under the curve: 0.989) and TMF cells (0.652; 0.880; 0.790) complement LDCT in diagnosing NSCLC in Lung-RADS 4 patients.

CONCLUSION

Cellular liquid biomarkers have a potential to complement LDCT interpretation of suspicious Lung-RADS 4 nodules to distinguish NSCLC from benign lung nodules. A future prospective, large-scale, multicenter clinical trial should validate the role of cellular liquid biomarkers in improving diagnostic accuracy in high-risk patients with Lung-RADS 4 nodules.
Intraoperative Inspiratory Oxygen Fraction and Myocardial Injury After Noncardiac Surgery: Results From an International Observational Study in Relation to Recent Controlled Trials
Authors: Pedersen Sofie S. , Holse Cecilie , Mathar Clara E. , Chan Matthew T. V. , Sessler Daniel I. , Liu Yingzhi , Zhang Lin , Kurz Andrea , Jacka Mike , Torborg Alexandra , Biyase Thuli , Montes Felix R. , Wang Chew Yin , Pettit Shirley , Devereaux P. J. , Meyhoff Christian S.
Published: April 2022

BACKGROUND:

Two trials reported that a high inspiratory oxygen fraction (Fio
2) does not promote myocardial infarction or death. Observational studies can provide larger statistical strength, but associations can be due to unobserved confounding. Therefore, we evaluated the association between intraoperative Fio
2 and cardiovascular complications in a large international cohort study to see if spurious associations were observed.

METHODS:

We included patients from the Vascular events In noncardiac Surgery patIents cOhort evaluatioN (VISION) study, who were ≥45 years of age, scheduled for overnight hospital admission, and had intraoperative Fio
2 recorded. The primary outcome was myocardial injury after noncardiac surgery (MINS), and secondary outcomes included mortality and pneumonia, all within 30 postoperative days. Data were analyzed with logistic regression, adjusted for many baseline cardiovascular risk factors, and illustrated in relation to findings from 2 recent controlled trials.

RESULTS:

We included 6588 patients with mean age of 62 years of whom 49% had hypertension. The median intraoperative Fio
2 was 0.46 (5%–95% range, 0.32–0.94). There were 808 patients (12%) with MINS. Each 0.10 increase in median Fio
2 was associated with a confounder-adjusted increase in odds for MINS: odds ratio (OR), 1.17 (95% confidence interval [CI], 1.12–1.23; P < .0001). MINS occurred in contrast with similar frequencies and no significant difference in controlled trials (2240 patients, 194 events), in which patients were given 80% vs 30% oxygen. Mortality was 2.4% and was not significantly associated with a median Fio
2 (OR, 1.07; 95% CI, 0.97–1.19 per 0.10 increase; P = .18), and 2.9% of patients had pneumonia (OR, 1.05; 95% CI, 0.95–1.15 per 0.10 increase; P = .34).

CONCLUSIONS:

We observed an association between intraoperative Fio
2 and risk of myocardial injury within 30 days after noncardiac surgery, which contrasts with recent controlled clinical trials. Fio
2 was not significantly associated with mortality or pneumonia. Unobserved confounding presumably contributed to the observed association between Fio
2 and myocardial injury that is not supported by trials.
The Homoerotics of “Negrotarian” Patronage in Langston Hughes’s “The Blues I’m Playing”
Authors: Kang Nancy
Published: April 2022

This essay argues that Langston Hughes’s acclaimed short story “The Blues I’m Playing” (1934) offers provocative feminist and queer insights into “Negrotarian” patronage of the early twentieth century. Against the backdrop of the Harlem Renaissance, the discussion sets out to define an interracial, intergenerational homoerotics of patronage between the white widowed elder, Mrs. Dora Ellsworth, and young Black pianist, Ms. Oceola Jones. The discussion places in stark relief the patron’s erotic competition with her protégée’s working-class African American fiancé. The article also grapples with topics like racialized obsession, the role of community in a black artist’s self-concept, and the best avenues for interracial solidarity across planes of difference. Understanding mature women’s legitimacy as sexual subjects and the persistence of queer loneliness (despite class and race privilege) also come to the fore.
Effects of ocean acidification over successive generations decrease resilience of larval European sea bass to ocean acidification and warming but juveniles could benefit from higher temperatures in the NE Atlantic
Authors: Howald Sarah , Moyano Marta , Crespel Amélie , Kuchenmüller Luis L. , Cominassi Louise , Claireaux Guy , Peck Myron A. , Mark Felix C.
Published: April 2022

European sea bass (Dicentrarchus labrax) is a large, economically important fish species with a long generation time whose long-term resilience to ocean acidification (OA) and warming (OW) is not clear. We incubated sea bass from Brittany (France) for two generations (>5 years in total) under ambient and predicted OA conditions (PCO2: 650 and 1700 µatm) crossed with ambient and predicted OW conditions in F1 (temperature: 15–18°C and 20–23°C) to investigate the effects of climate change on larval and juvenile growth and metabolic rate. We found that in F1, OA as a single stressor at ambient temperature did not affect larval or juvenile growth and OW increased developmental time and growth rate, but OAW decreased larval size at metamorphosis. Larval routine and juvenile standard metabolic rate were significantly lower in cold compared with warm conditioned fish and also lower in F0 compared with F1 fish. We did not find any effect of OA as a single stressor on metabolic rate. Juvenile PO2,crit was not affected by OA or OAW in both generations. We discuss the potential underlying mechanisms resulting in the resilience of F0 and F1 larvae and juveniles to OA and in the beneficial effects of OW on F1 larval growth and metabolic rate, but contrastingly in the vulnerability of F1, but not F0 larvae to OAW. With regard to the ecological perspective, we conclude that recruitment of larvae and early juveniles to nursery areas might decrease under OAW conditions but individuals reaching juvenile phase might benefit from increased performance at higher temperatures.
Women’s literacy and children’s mortality rate among Southeast Asia countries 1991-2020: a cross-sectional study
Authors: Satria Fauzi Budi , Lubis Rahayu , Hsu Yi-Hsin Elsa , Iqbal Usman
Published: April 2022

Background: Women’s literacy is often associated with the health status of family members, especially children. Unfortunately, in some regions of Southeast Asia, the rates of women’s literacy (WL) are still very low, and in these areas, children’s mortality rates (CMR) are also very high. This study aims to identify the changes and correlation between women's literacy and children’s mortality rate among Southeast Asian Countries in the last 3 decades.

Methods: In this cross-sectional study, we included 11 Southeast Asian countries; Brunei Darussalam, Cambodia, Indonesia, Lao, Malaysia, Myanmar, Philippines, Singapore, Thailand, Timor Leste, and Vietnam. The WL and CMR were the independent and dependent variables respectively. The CMR was measured by mortality rates in infant (IMR), neonatal (NMR), and under-fives (UFMR). We collected data for all variables from the World Bank website, and used the data from 1991 to 2020 for analysis. Kruskal–Wallis and Pearson correlation test were performed to identify the significant difference between variables and its correlation respectively. Then, we conducted linear regression analysis to identify how the WL affected the CMR in 11 Southeast Asian countries from 1991 to 2020.

Results: In the last 30 years period, we found that the CMR trends in Southeast Asian countries vary. Moreover, during the same period, WL and CMR were changed significantly. Across these 11 countries, the correlation between WL and IMR was the highest (R=0.805). However, only 65% of IMR can be explained by WL ​​(R2=0.65).

Conclusion: This study found that women's literacy had a significant impact on CMR in Southeast Asian countries. However, improvement in multiple sectors including governance, economy, freedom, health system, education, and gender equality is required to help countries in this region achieve the United Nations’ Sustainable Development Goals target by 2030.
Maltitol based sugar-free chocolates may not promote dental caries: An open-label clinical study
Authors: Mehta Arti , Bapna Arohi , Joshi Parth , Arora Tarun , Raghavan Govindarajan
Published: April 2022

Background: Sugar substitutes like maltitol are reported to be noncariogenic ingredients and may not lead to the development of dental caries (DC), in contrast to sugars and other fermentable carbohydrates. The current study aimed to investigate the effects of maltitol-based sugar-free chocolates on factors associated with DC.

Methods: This was an open-label study involving healthy human volunteers. A total of 15 healthy human subjects were screened and enrolled in the study after obtaining their signed informed consent. The subjects were administered the test product, maltitol-based sugar-free chocolate, which contains no added sugar (sucrose). Sucrose was completely replaced with the sweeteners maltitol (minimum 45%) and steviol glycoside (0.05%). Salivary pH was measured using a digital pH meter at baseline and 0 h, 1 h, 2 h, and 4 h after test product consumption. The saliva samples were collected for measurement of Streptococcus mutans colonies at baseline and at 0 h and 4 h after test product consumption. The data were subjected to two-sided tests, at a 5% level of significance using Statistical Analysis System (SAS) 9.4 software (SAS Institute Inc., NC Cary).

Results: A statistically significant increase in the salivary pH level from the baseline at 0 h measurement (p = 0.0181) and a reduction in S. mutans formation from baseline to 0 h and 4 h, respectively (p = 0.0001) were noted.

Conclusion: Maltitol-based sugar-free chocolates were found to be safe for consumption and were devoid of cariogenic potential.
Anti-inflammatory activity and toxicity evaluation of 1,3-bis(p-hydroxyphenyl)urea
Authors: Waruwu Syukur Berkat , Harahap Urip , Yuandani Yuandani , Purnomo Hari , Satria Denny
Published: April 2022

Background: Inflammation is a normal protective response caused by an injury or tissue damage, through physical trauma, damaging chemicals, or invasion of pathogenic microorganisms. One of the modified p-aminophenol compounds is 1,3-bis(p-hydroxyphenyl)urea, which was estimated to have more potent analgesic activity and fewer hepatotoxic side effects than paracetamol. When the lipophilicity of this compound increases between 1.8 to 4.4, it is observed to serve as an anti-inflammatory agent. Therefore, the determination of safety precaution is very necessary while testing for the toxicity effect of 1,3-bis(p-hydroxyphenyl)urea. This is due to the effectiveness and safety of suitable drugs.

Methods: An anti-inflammatory test was carried out by measuring the percentage of inflammation in rats, after the administration of 1,3-bis(p-hydroxyphenyl)urea was previously induced by the carrageenan solution intraplantar and the analysis of neutrophil values through a plethysmometer and Hematoxylin-Eosin method. Also, an acute toxicity test was performed by administering this p-aminophenol compound to female rats for 24 h and observed for 14 days. In addition, a subchronic toxicity test was conducted on male and female rats for 28 days, with continuous observations carried out for 42 days.

Results: The doses of 1,3-bis(p-hydroxyphenyl)urea at 50, 100, and 200 mg/Kg BW, had anti-inflammatory activity compared to diclofenac sodium at 2.25 mg/Kg BW. Also, there is no toxicity and animal death symptoms were observed in the acute and subchronic tests.

Conclusion: This 1,3-bis(p-hydroxyphenyl)urea compound had an anti-inflammatory activity and relatively low toxicity.
Video lectures on the discipline of «Chemistry» for students of specialty «Dentistry»
Authors:   Novosibirsk State Medical University, Terah E.I.
Published: April 2022

There are video lectures on chemistry for students of the specialty "Den-tistry": 6 lectures on general chemistry and 11 lectures on bioorganic chemistry. The total duration of the video lectures is 13 hours 17 minutes. In lectures on general chemistry, the basic provisions of chemical ther-modynamics and kinetics, chemical equilibrium, dispersed systems, solutions and their properties, ionic equilibria in solutions of elektrolites, buffer solutions, hydrolysis are considered. Lectures on bioorganic chemistry discuss the properties and importance of biologically important compounds, including proteins, carbohydrates, nucleic acids and fats, as well as issues of lipid peroxidation, antioxidant protection.
An annotated catalogue of the Paraguayan Sphingidae (Lepidoptera)
Authors: SMITH PAUL , KITCHING IAN , RÍOS SERGIO , HAXAIRE JEAN
Published: April 2022

Although the Sphingidae (hawkmoths) of Paraguay are moderately well-known, comprehensive publications on the fauna are few and far between, and there is no modern taxonomic and biogeographical overview of the available data against which future researchers could work. Here we compile existing published data and review important national collections to provide a preliminary understanding of the distributions of Sphingidae species in the country. The presence of 100 species is documented, with a further three species pending documentation, three species considered to be of potential occurrence and seven species considered to have been erroneously cited. A complete bibliography of Paraguayan Sphingidae is provided, as well as taxonomic discussion, and a first attempt is made to associate sphingid species’ distributions with the ecoregions present in the country. Four species are documented for Paraguay for the first time: Cocytius mephisto Haxaire & Vaglia, 2002, Manduca exiguus (Gehlen, 1942), Erinnyis impunctata Rothschild & Jordan, 1903 and Xylophanes marginalis Clark, 1917. Paraguayan specimens previously assigned to Xylophanes porcus (Hübner, [1823]) are re-assigned to the recently described species Xylophanes alineae Haxaire & C. Mielke, 2017 and Xylophanes soaresi Haxaire & C. Mielke, 2017. In addition, specimens of species previously named as Manduca sexta (Linnaeus, 1771) and Protambulyx eurycles (Herrich-Schäffer, [1854]) are referred to Manduca paphus (Cramer, 1779) and Protambulyx fasciatus (Gehlen, 1928) respectively. A provisional new taxonomic arrangement of the Paraguayan species of the genus Neogene Rothschild & Jordan, 1903 is also proposed in which Neogene pictus Clark, 1931 syn. nov. and Neogene intermedia Clark, 1935 syn. nov. are synonymized with Neogene reevei (Druce, 1882), and Neogene albescens Clark, 1929 syn. nov. is synonymized with Neogene steinbachi Clark, 1924.
Compact thermal imager: a flight demonstration of infrared technology for Earth observations
Authors: Jennings D. E. , Jhabvala M. D. , Tucker C. J. , Lunsford A. W. , La A. T. , Flatley T. P. , Choi K. K. , Wu D. L. , Morton D. C. , Holmes T. R. , Fitts Y. , Cappelaere P. G. , Cillis A. N. , Turck K. A. , Hewagama T.
Published: April 2022

During 2019, an infrared camera, the compact thermal imager (CTI), recorded 15 million images of the Earth from the International Space Station. CTI is based on strained-layer superlattice (SLS) detector technology. The camera covered the spectral range from 3 to 11 µm in two spectral channels, 3.3–5.4 and 7.8–10.7 µm. Individual image frames were

26

×

21

k
m

2

projected on the ground, with 82 m pixel resolution. A frame time of 2.54 s created continuous image swaths with a 13% along-track image overlap. Upper limits determined on the ground and in flight for the electronic offset, read noise, and dark current demonstrated the stability of the SLS detector and camera over many months. Temperature calibration was established using a combination of preflight and in-flight measurements. A narrowband approximation of temperature as a function of photon counts produced an analytic relationship covering a temperature range of 0°–400°C. Examples of CTI images illustrate temperature retrievals over sea ice, urban and agricultural areas, desert, and wildfires.
Fabrication of a fractal pattern device for focus characterizations of
X-ray imaging systems by Si deep reactive ion etching and bottom-up Au
electroplating
Authors: Shi Zhitian , Josell Daniel , Jefimovs Konstantins , Romano Lucia , Moffat Thomas P. , Stampanoni Marco , Schlepütz Christian M.
Published: April 2022

Precisely aligned optical components are crucial prerequisites for X-ray tomography at high resolution. We propose a device with a fractal pattern for precise automatic focusing. The device is etched in a Si substrate by deep reactive ion etching and then filled by a self-terminating bottom-up Au electroplating process. The fractal nature of the device produces an X-ray transmission image with globally homogeneous macroscopic visibility and high local contrast for pixel sizes in the range of 0.165 µm to 11 µm, while the high absorption contrast provided between Au and Si enables its use for X-ray energies ranging from 12 keV to 40 keV.
Separating single- and multiple-scattering components in laser speckle contrast imaging of tissue blood flow
Authors: Zhang Yifan , Wang Cheng , Tong Shanbao , Miao Peng
Published: April 2022

Random matrix theory provides new insights into multiple scattering in random media. In a recent study, we demonstrated the statistical separation of single- and multiple-scattering components based on a Wishart random matrix. The first- and second-order moments were estimated with a Wishart random matrix constructed using dynamically backscattered speckle images. In this study, this new strategy was applied to laser speckle contrast imaging (LSCI) of in vivo blood flow. The random matrix-based method was adopted and parameterized using electric field Monte Carlo simulations and in vitro blood flow phantom experiments. The new method was further applied to in vivo experiments, demonstrating the benefits of separating the single- and multiple-scattering components, and the method was compared with the traditional temporal laser speckle contrast analysis (LASCA) method. More specifically, the new method separates the stimulus-induced functional changes in blood flow and tissue perfusion in the superficial (<2l
t
, l
t
is the transport mean free path) and deep layers (1l
t
 ∼ 7l
t
), extending LSCI to the evaluation of functional and pathological changes.
Performance trade-offs in reconfigurable networks for HPC
Authors: Teh Min Yee , Wu Zhenguo , Glick Madeleine , Rumley Sebastien , Ghobadi Manya , Bergman Keren
Published: April 2022

Designing efficient interconnects to support high-bandwidth and low-latency communication is critical toward realizing high performance computing (HPC) and data center (DC) systems in the exascale era. At extreme computing scales, providing the requisite bandwidth through overprovisioning becomes impractical. These challenges have motivated studies exploring reconfigurable network architectures that can adapt to traffic patterns at runtime using optical circuit switching. Despite the plethora of proposed architectures, surprisingly little is known about the relative performances and trade-offs among different reconfigurable network designs. We aim to bridge this gap by tackling two key issues in reconfigurable network design. First, we study how cost, power consumption, network performance, and scalability vary based on optical circuit switch (OCS) placement in the physical topology. Specifically, we consider two classes of reconfigurable architectures: one that places OCSs between top-of-rack (ToR) switches—ToR-reconfigurable networks (TRNs)—and one that places OCSs between pods of racks—pod-reconfigurable networks (PRNs). Second, we tackle the effects of reconfiguration frequency on network performance. Our results, based on network simulations driven by real HPC and DC workloads, show that while TRNs are optimized for low fan-out communication patterns, they are less suited for carrying high fan-out workloads. PRNs exhibit better overall trade-off, capable of performing comparably to a fully non-blocking fat tree for low fan-out workloads, and significantly outperform TRNs for high fan-out communication patterns.
Influence of optical “dipoles” on the topological charge of a field with a fractional initial charge
Authors: Nalimov A. G. , Kotlyar V. V.
Published: April 2022

In this work, using the Rayleigh–Sommerfeld integral and Berry formula, a topological charge (TC) of a Gaussian optical vortex with an initial fractional TC in the far field was calculated. It was found that, for diverse fractional parts of the TC, the beam contained different numbers of screw dislocations, which determined the TC of the entire beam. If a fractional part of the TC was small, the beam consisted of the main optical vortex centered on the optical axis, with the TC equal to the nearest integer (say

n
>

0

) and two edge dislocations located on the vertical axis (one above and the other below the center). When the fractional part of the initial TC increased, a “dipole” was formed from the upper edge dislocation, consisting of two vortices with TCs equal to

+

1

and

−

1

. With a further increase in the fractional part, the additional vortex with

T
C

=
+

1

moved to the center of the beam, and the vortex with

T
C

=
−

1

moved to the periphery. When the fractional part of the TC increased further, another “dipole” was formed from the lower edge dislocation, in which, on the contrary, the vortex with

T
C

=
−

1

was displaced to the optical axis (to the center of the beam) and the vortex with

T
C

=
+

1

moved to the beam periphery. When the fractional part of the TC became equal to 1/2, the lower vortex with a

T
C

=
−

1

, which was earlier displaced to the center of the beam, began to shift to the periphery, and the upper vortex with a

T
C

=
+

1

moved closer and closer to the center of the beam, eventually merging with the main vortex when the fractional part approached 1. Such dynamics of additional vortices with TCs above

+

1

and below

−

1

determined which whole TC the beam would have (

n

or

n
+

1

) for different values of the fractional part from the segment [

n
,

n
+

1

]. Our analysis has shown that, for any value of the fractional part of the initial topological charge, the TC of the beam in the far field will not be determined. Since, with an increase in the radius of the circle in the beam section on which the TC is calculated, more optical “dipoles” will appear, and the TC will be either

n

or

n
+

1

.
High-energy single-frequency pulsed fiber MOPA at 1064 nm based on a hybrid active-fiber
Authors: Shi Chaodu , Tian Hao , Fu Shijie , Sheng Quan , Shi Zheng , Jiang Peiheng , Shi Wei , Yao Jianquan
Published: April 2022

We report a single-frequency pulsed Yb-doped fiber master-oscillator-power-amplifier at 1064 nm producing output with pulse energy of 0.6 mJ for a pulse width of 95 ns at a pulse repetition frequency of 5 kHz. Integral to this laser design was the application of a hybrid active-fiber, which integrated a length of heavily Yb-doped phosphosilicate fiber (with a core diameter of 50 μm) with a silica gain fiber (with core diameter of 35 μm). This was used in the power amplifier stage to both suppress stimulated Brillouin scattering and to enhance the gain saturation for improved efficiency and spectral signal to noise ratio. The seed pulses were pre-shaped so that sawtooth-like pulses were obtained after amplification, this having the effect of preventing linewidth broadening induced by self-phase modulation. A spectral linewidth of ∼15 MHz was measured at the maximum peak power of 6.3 kW.
Fine-grained all-fiber nonlocal dispersion compensation in the telecommunications O-band
Authors: Chua RuiMing , Grieve James A. , Ling Alexander
Published: April 2022

Nonlocal dispersion compensation between broadband nondegenerate photon pairs propagated over fiber corresponding to the ITU-T G.652D telecommunications standard was studied extensively via fine-grained measurements of the temporal correlation between them. We demonstrated near-ideal levels of nonlocal dispersion compensation by adjusting the propagation distance of the photon pairs to preserve photon timing correlations close to the effective instrument resolution of our detection apparatus (41.0±0.1ps). Experimental data indicates that this degree of compensation can be achieved with relatively large fiber increments (1km), compatible with real-world deployment. Ultimately, photon timing correlations were preserved down to 51ps±21ps over two multi-segmented 10km spans of deployed metropolitan fiber.
A time-delay signature elimination and broadband electro-optic chaotic system with enhanced nonlinearity by deep learning
Authors: Lu Yuantong , Wang Hongxiang , Ji Yuefeng
Published: April 2022

In this paper, a novel electro-optic chaotic system with enhanced nonlinearity by deep learning (ENDL) is proposed to achieve time-delay signature (TDS) elimination. A long-short term memory network (LSTM) is trained by a specially designed loss function to enhance the nonlinear effect that can hide the TDS of the system. For the first time, the trained deep learning module is put into a single feedback loop to participate in chaos generation. Simulation results show that the ENDL system can eliminate TDS and increase the bandwidth to more than 31GHz when the feedback intensity is very low (α = 4V). Moreover, the complexity of the chaotic output can be improved with permutation entropy (PE) reaching 0.9941. The synchronization result shows that the ENDL system has high sensitivity to TDS but has low sensitivity to the feedback intensity, thus the system has both high security and high robustness. This system has an uncomplicated synchronization structure and high flexibility, and it opens up a new direction for high-quality chaos generation.
Dynamic strain measurement in Brillouin optical correlation-domain sensing facilitated by dimensionality reduction and support vector machine
Authors: Yao Yuguo , Mizuno Yosuke
Published: April 2022

Brillouin optical correlation-domain sensing enables high-speed Brillouin gain spectrum (BGS) measurement at random positions along the optical fiber. To extract the Brillouin frequency shift (BFS) that reflects the real-time strain information, machine learning methods of principal components analysis (PCA) and support vector machine (SVM) are used in the signal processing for the BGSs. The performances of dimensionality reduction by PCA and SVM based on classification and regression are analyzed and compared. The experiment demonstrates an 8 kHz BGS acquisition repetition rate and an average BFS extraction time of 0.0104 ms, which is 27.3 times faster than the conventional method with no PCA. The proposed methods realize a real-time dynamic strain measurement at the frequency of 40 Hz.
Measurement of the quantum-confined Stark effect in InAs/In(Ga)As quantum dots with p-doped quantum dot barriers
Authors: Mahoney Joe , Tang Mingchu , Liu Huiyun , Abadía Nicolás
Published: April 2022

The quantum-confined Stark effect in InAs/In(Ga)As quantum dots (QDs) using non-intentionally doped and p-doped QD barriers was investigated to compare their performance for use in optical modulators. The measurements indicate that the doped QD barriers lead to a better figure of merit (FoM), defined as the ratio of the change in absorption Δα for a reverse bias voltage swing to the loss at 1 V α(1 V), FoM=Δα/α (1 V). The improved performance is due to the absence of the ground-state absorption peak and an additional component to the Stark shift. Measurements indicate that p-doping the QD barriers can lead to more than a 3x increase in FoM modulator performance between temperatures of −73 °C to 100 °C when compared with the stack with NID QD barriers.
Single photon imaging with multi-scale time resolution
Authors: Chen Zhen , Liu Bo , Guo Guangmeng , He Cheng
Published: April 2022

To avoid echo photons to be submerged in noise in rough terrain or dynamic applications, a single photon imaging mechanism with multi-scale time resolution is proposed in this paper. Combining with adaptively thresholding technique, multiple histograms with different time resolutions are produced to cluster the echo photons into a time bin and then separate them from the noise. With microsecond-scale resolution, uncertainty in the position of an object can be reduced from several kilometers to 300 meters, and therefore the computational overheads are saved by only investigating depths with picosecond-scale resolution where an object is present. Reconstructed results of the two near surfaces show that the depth accuracy is less than 0.15 m in the conditions of 8 echo photons and 1 Mcps background count rate, even though the pulse width of laser source reaches 3.5 ns (equivalent to an uncertainty of 0.525 m). In addition, the echo can be distinguished from the noise clearly when the background count rate varies from 200 kcps to 1 Mcps. The proposed method is suitable for implementation in digital signal processor (DSP) due to low data volumes and computational overheads.
Design considerations and performance analysis of a fiber laser array system for structuring orbital angular momentum beams: a simulation study
Authors: Hou Tianyue , Chang Qi , Long Jinhu , Ma Pengfei , Zhou Pu
Published: April 2022

Since the advent of optical orbital angular momentum (OAM), advances in the generation and manipulation of OAM beams have continuously impacted on intriguing applications including optical communication, optical tweezers, and remote sensing. To realize the generation of high-power and fast switchable OAM beams, coherent combining of fiber lasers offers a promising way. Here in this contribution, we comprehensively investigate the coherent fiber laser array system for structuring OAM beams in terms of the design considerations and performance analysis. The performance metric and evaluation method of the laser array system are presented and introduced. Accordingly, the effect of the main sections of the laser array system, namely the high-power laser sources, emitting array configuration, and dynamic control system, on the performance of the output coherently combined OAM beams is evaluated, which reveals the system tolerance of perturbative factors and provides the guidance on system design and optimization. This work could provide beneficial reference on the practical implementation of spatially structuring high-power, fast switchable OAM beams with fiber laser arrays.
Local resolution characteristics of atmospheric turbulence
Authors: Hunt Bobby R. , Iler Amber L. , Sheppard David G.
Published: April 2022

D. L. Fried’s concept of a “Lucky Image” for turbulent image streams can be seen as creating different degrees of localized resolution in images. These localized regions of resolution can be derived from Fried’s equation for the probability of obtaining a Lucky Image. The existence of local resolution variations when imaging through turbulence also implies local variations in the point-spread-functions (PSFs) caused by turbulence. We characterize these local variations by using simple measures on PSFs collected in the presence of atmospheric turbulence. We also compile these variations into an empirical probability density function (PDF) that describes the different resolutions in local regions of turbulent imagery and can be used to characterize specific conditions of turbulence, e.g., the coherence diameter.
High-power tunable dual-wavelength diode laser with a composite external cavity
Authors: Lu Yuhuan , Zhang WeiQiao , Fan Jian , Zhou Xuyan , Wang Yufei , Qu Hongwei , Zheng Wanhua
Published: April 2022

A high-power tunable dual-wavelength composite external cavity architecture obtained by means of a holographic grating and a volume Bragg grating is proposed and demonstrated. The tunable frequency difference of the dual-wavelength output is from 0.41 THz to 3.89 THz. We obtain an output power of 2.1 W when the frequency difference is 1.86 THz. The side-mode suppression ratio of more than 29 dB is suppressed over the entire tunable dual-wavelength output range. The two corresponding wavelengths of the dual-wavelength output basically maintain the same intensity with the smallest power difference of only 0.10%.
Temporal multi-stage energy pumping
Authors: Mai Wending , Xu Jingwei , Werner Douglas H.
Published: April 2022

As an important theoretical concept, temporal boundaries provide researchers with new insights for tailoring electromagnetic waves in the time domain. Because a temporal boundary breaks the time translation symmetry, a source is necessary to satisfy energy conservation. In this Letter, we quantify the relationship between refractive index contrast and the required energy exchange. More specifically, to realize a temporal boundary with a large refractive index contrast, a correspondingly large and abrupt energy exchange is required. Considering this practical difficulty, we propose to mimic a large-contrast temporal boundary by staggering a series of small-contrast temporal boundaries separated by carefully designed durations. In this way, the process of energy input/output is distributed over an elongated duration, but their effect can still be cumulative. This process is analogous to a multi-resonant system with a periodic energy input. Based on this design principle, we discuss several scenarios for different temporal profiles of refractive index and their corresponding energy requirements.
Tunable Cherenkov radiation based on a van der Waals semiconductor α-MoO3 and graphene hybrid
Authors: Xue Shuwen , Zeng Yali , Bao Qiaoliang , Zhu Shan , Chen Huanyang
Published: April 2022

In this Letter, we explore the Cherenkov radiation properties of α-phase molybdenum trioxide (α-MoO3). We demonstrate that the asymmetric, forward, and reverse Cherenkov radiation can simultaneously exist by rotating the α-MoO3 slab at the same working frequency and structure. In addition, thanks to the tunable functionalities of graphene, the conversion of forward and reverse Cherenkov radiation can be actualized by altering the Fermi level of graphene. These dynamically adjustable features provide a novel, to the best of our knowledge, and intuitive way for tunable Cherenkov radiation in the mid-infrared range, which opens up new opportunities in designing and manufacturing tunable radiation sources in future.
Surface plasmon resonance based tunable D-shaped single polarization filter at the communication band
Authors: Pandey Tanmoy , Islam Md. Arefin , Paul Alok Kumar , Ahmed Tanvir
Published: April 2022

A surface plasmon resonance based D-shaped tunable and broadband single-polarization filter is proposed. The complex propagation constants and the guided modes’ corresponding field profiles are calculated using the full-vector finite element method based COMSOL Multiphysics v5.0 software. From the simulation study, it is found that the confinement losses of the desired x-polarized mode are 0.17 dB/cm, and 0.30 dB/cm at the resonance wavelength of 1.31 µm, and 1.55 µm, respectively, while the losses for y-polarized unwanted guided mode are 736.30 dB/cm, and 573.32 dB/cm at the mentioned wavelengths, respectively. It is also evident that the proposed fiber offers a crosstalk of 625.10 dB at the wavelength of 1.31 µm, and 495.31 dB at the wavelength of 1.55 µm with the corresponding bandwidth of 490 nm and 485 nm over which the crosstalk is more than 20 dB for a fiber length of 1.0 mm. The study also underpins that the resonant peak shifts linearly with the change of lattice constant, radius of the gold-coated channel in the polished surface, and the size and the distance between the tuning air holes of the proposed filter. Hence, this filter can be a potential fit for micro-integration in optical systems.
Chaotic and stochastic dynamics of epileptiform-like activities in sclerotic hippocampus resected from patients with pharmacoresistant epilepsy
Authors: Araújo Noemi S. , Reyes-Garcia Selvin Z. , Brogin João A. F. , Bueno Douglas D. , Cavalheiro Esper A. , Scorza Carla A. , Faber Jean
Published: April 2022

The types of epileptiform activity occurring in the sclerotic hippocampus with highest incidence are interictal-like events (II) and periodic ictal spiking (PIS). These activities are classified according to their event rates, but it is still unclear if these rate differences are consequences of underlying physiological mechanisms. Identifying new and more specific information related to these two activities may bring insights to a better understanding about the epileptogenic process and new diagnosis. We applied Poincaré map analysis and Recurrence Quantification Analysis (RQA) onto 35in vitroelectrophysiological signals recorded from slices of 12 hippocampal tissues surgically resected from patients with pharmacoresistant temporal lobe epilepsy. These analyzes showed that the II activity is related to chaotic dynamics, whereas the PIS activity is related to deterministic periodic dynamics. Additionally, it indicates that their different rates are consequence of different endogenous dynamics. Finally, by using two computational models we were able to simulate the transition between II and PIS activities. The RQA was applied to different periods of these simulations to compare the recurrences between artificial and real signals, showing that different ranges of regularity-chaoticity can be directly associated with the generation of PIS and II activities.