bluuebunny/crossref_metadata_2025 huggingface dataset:
443 Intrathecal Fentanyl With a Myofascial Plane Block in Open Lumbar Surgeries
Authors: Metcalf Tyler , Sielatycki John A. , Schatzman Nathan , Devin Clinton J. , Goldstein Jeffrey A. , Hodges Scott
Published: March 2022

INTRODUCTION:

Acute postoperative pain control following lumbar surgery is imperative to minimizing long term narcotic use and associated adverse sequela. The utility and safety of intrathecal morphine for postoperative pain management in spine surgery has been investigated; however, to date, no studies have investigated the safety of intrathecal fentanyl with a myofascial plane block in lumbar procedures.

METHODS:

An intraoperative intrathecal injection of fentanyl and a myofascial plane block was administered in 40 patients undergoing open lumbar surgery. The procedure performed was an open decompression with lumbar total joint reconstruction at one to three lumbar levels. Postoperative complications including urinary retention, respiratory depression, and need for IV opioid use were recorded.

RESULTS:

Postoperatively, zero of the study patients required IV opioid medication for supplemental pain control. Thirty-six patients (85%) were discharged same-day or prior to 23 hours postoperatively. No intrathecal fentanyl-related perioperative complications were noted. Zero of the 40 listed patients experienced urinary retention or delayed respiratory depression. One patient (2%) experienced orthostatic hypotension postoperative day one, which resolved upon discontinuation of oral oxycodone.

CONCLUSION:

Intrathecal fentanyl and myofascial plane block may be a safe option for perioperative pain control and may reduce the need for supplemental intravenous opioids without increased risk of respiratory depression, urinary retention, or other sequelae. Further studies are necessary to compare the efficacy of intrathecal fentanyl to other analgesia techniques.
802 First United States Experience with Pipeline Flex with Shield Technology for Treatment of Intracranial Aneurysms
Authors: Monteiro Andre , Cappuzzo Justin Mark , Taylor Maritza Nicole , Waqas Muhammad , Baig Ammad , Davies Jason , Snyder Kenneth Vincent , Siddiqui Adnan Hussain , Levy Elad I.
Published: March 2022

INTRODUCTION:

Pipeline Flex with Shield technology (PED-Shield) is a third generation flow-diverter. A surface modification of the mesh with phosphorylcholine covalently bound to the metal struts aims to reduce thrombogenicity. In this study, we report the first United-States series of patients treated with the PED-Shield.

METHODS:

Information for the first 10 patients with intracranial aneurysms treated with PED-Shield was retrospectively collected. Patients were started on dual antiplatelet therapy (DAPT; 325 mg of aspirin and 75 mg of clopidogrel or 180 mg of ticagrelor) 7-days prior to intervention. After procedure, all patients were discharged on DAPT and planned to switch to aspirin alone at 6 months.

RESULTS:

Ten patients with 11 intracranial wide-necked aneurysms underwent treatment with PED-Shield between June 2021 and July 2021. The mean age of patients was 64.7 (45 - 86), and nine were female. All aneurysms were unruptured and located in the anterior-circulation. Mean maximum aneurysm diameter was 4.86mm, mean neck width was 3.05mm. Regarding morphology, all aneurysms were saccular except for one, which was fusiform. In one case, the device demonstrated insufficient distal opening, which was repaired with balloon angioplasty. There were no other technical issues or intraoperative complications. We observed no endoleak after deployment of the devices. There were two complications in the post-operative period: one patient had a groin hematoma, which was attributed to failure of the closure device and successfully managed with no clinical repercussions; one patient experienced an asymptomatic distal small intraparenchymal hematoma and trace subarachnoid hemorrhage on post-procedure non-contrast CT, which remained stable over several days. None of the patients experienced transient ischemic attacks or strokes. All patients were discharged in stable condition and unchanged functional status.

CONCLUSIONS:

In our initial experience with PED-Shield for the treatment of intracranial aneurysms, the device demonstrated excellent performance and no major complications. Further studies are needed to evaluate long term follow-up and safety of different antiplatelet regimens.
804 Should the Direct Aspiration First Pass Technique be Advocated over the StentRetriever Technique for Acute Ischemic Stroke? A Meta-analysis of 7692 patients
Authors: Ghaith Hazem , Diaa Mohamed , Negida Ahmed , Kanmounye Ulrick Sidney , Elfil Mohamed
Published: March 2022

INTRODUCTION:

The direct aspiration first pass technique (ADAPT) was developed to achieve better recanalization in acute ischemic stroke patients. However, data from the literature are controversial regarding the comparative outcomes of this technique compared to the conventional thrombectomy by stent retriever (SR).

METHODS:

We searched PubMed, Scopus, Web of Science, and Cochrane Central Register of Controlled Trials from inception to March 2021 for relevant clinical trials and observational studies. Eligible studies were identified, and all relevant outcomes were pooled in the meta-analysis random-effects model of DerSimonian-Liard.

RESULTS:

Thirty studies were included in the meta-analysis with a total of 7868 patients. Compared with the SR, the ADAPT provides slightly higher rates of successful recanalization (RR 1.06, 95% CI [1.02 to 1.10]) and complete recanalization (RR 1.20, 95% CI [1.01 to 1.43]) but with more need for rescue therapy (RR 1.81, 95% CI [1.29 to 2.54]). There were no significant differences between the two techniques in terms of mortality at discharge, mortality at 90 days, change in the National Institutes of Health Stroke Scale (NIHSS) score, the favorable outcome (modified Rankin scale (mRS) of 0-2), time to the groin puncture, or frequency of complications as intracerebral hemorrhage (ICH), symptomatic ICH (sICH), the occurrence of an embolus in a new territory, hemorrhagic infarction, parenchymal hematoma, subarachnoid hemorrhage (SAH), and procedural complications (all P>0.05).

CONCLUSIONS:

Current evidence supports the use of the ADAPT technique to achieve successful and complete recanalization while considering the higher need for rescue therapy in some patients. Owing to its lower cost than the standard SR technique, we advocate that the ADAPT should replace the SR as the first-line thrombectomy technique in routine practice.
813 Early Surgical Decompression on Neurological Recovery in Traumatic Cervical ASIA A Spinal Cord Injury Patients
Authors: Moghaddamjou Ali , Wilson Jefferson R. , Fehlings Michael G.
Published: March 2022

INTRODUCTION:

While there is increasing evidence for the efficacy of early surgical decompression for traumatic cervical spinal cord injury (tSCI), the impact of early surgery on motor and sensory complete (ASIA A) patients is still the subject of debate. To date, there have been no studies focusing specifically on ASIA A cervical tSCI patients.

METHODS:

Patients with cervical ASIA A injury were identified from 4 prospective, multi-center datasets (NACTN, STASCIS, NASCIS 3, and SYGEN). Patients who had a GCS <15 at baseline or were younger than 18 or older than 80 were excluded. We tabulated the number of functional motor levels gained below the neurological level of injury. A functional motor level was defined as a myotome with at least grade 3 power on the MRC scale. We defined a gain of greater than 2 functional motor levels at 1 year as a significant improvement. A-priori we isolated age, mechanism of injury, and use of steroids for multivariate analysis. Logistic regression models were used to calculate the Odds Ratio for significant improvement.

RESULTS:

We identified 365 cervical ASIA A tSCI patients with an average age of 33yrs and an average time to surgery of 168 hrs. Of those patients who had early surgery, 39.40% had a significant improvement in functional motor levels vs. 28.80% of those who did not have early surgery (P = 0.049). In Multi-variate analyses, early surgery was the only significant covariate associate with a significant impact on functional recovery (Odds Ratio of 1.65 ; p= 0.048).

CONCLUSIONS:

For the first time, we have shown a clear therapeutic benefit of early surgical decompression within 24 hrs in ASIA A tCSCI patients. These data further support the principle of early surgical intervention for all types of SCI, even those with clinically complete lesions at baseline.
816 Traveling Waves Reveal a Dynamic Source of Human Focal Seizures and Interictal Spikes
Authors: Diamond Joshua M. , Diamond Benjamin , Chapeton Julio , Inati Sarah K. , Zaghloul Kareem A.
Published: March 2022

INTRODUCTION:

Treatment of patients with drug resistant focal epilepsy relies upon accurate seizure localization. Ictal activity captured in intracranial EEG (iEEG) has traditionally been interpreted to suggest that the underlying cortex is actively seizing. On the other hand, an emerging hypothesis suggests that seizures may in fact emerge from focal regions, which emit discharges that travel over the surface of the cortex as traveling waves.

METHODS:

20 patients underwent placement of subdural electrodes for invasive monitoring at the National Instutes of Health, underwent surgical resection for epilepsy, and had at least 1 year of follow-up. Outcomes were measured by the Engel scale. In these patients, we measured the time delay in discharge receipt at adjacent electrodes to compute the location of the seizure source. This algorithm, known as multilateration, has been used for signal source localization with sparsely-spaced sensors for over a century in geophysics, radar, and acoustics, but has not been used in epilepsy until the present.

RESULTS:

In patients with good outcome, but not in patients with poor outcome, the seizure source tends to localize to the resection territory. The source is a focal, dynamic entity that moves and evolves over the time course of a seizure. Our approach also successfully localizes interictal spikes. We find that interictal spikes emerge from multiple distinct foci in each patient. Seizures either arise from or travel to interictal spike generators.

CONCLUSIONS:

The seizure source appears to be more focal than has traditionally been conceptualized. This focal source may be localized by measuring the time difference of discharge receipt in intracranial electrodes. Algorithmic source localization, as performed here, may guide pre-surgical planning for drug-resistant epilepsy and may improve outcomes.
826 Gender Equality in Neurosurgery and Strategic Goals Towards a More Balanced Workforce
Authors: Plonsker Jillian Hannah , Benzil Deborah L. , Air Ellen L. , Woodrow Sarah , Stippler Martina , Ben-Haim Sharona
Published: March 2022

INTRODUCTION:

The Women in Neurosurgery (WINS) published a white paper in 2008 setting a goal for women to comprise 20% of neurosurgery residents by 2012 and 20% of practicing neurosurgeons by 2020. There has been notable progress toward these benchmarks, but we ultimately fell short of their achievement.

METHODS:

A literature review was performed PubMed, Google Scholar, and published data from Accreditation Council for Graduate Medical Education (ACGME) and other society websites. to perform a thorough progress assessment. The combined expertise and experience of the authors was used to create new specific recommendations.

RESULTS:

There was an exponential increase in the number of female neurosurgical trainees in the past several decades, the percentage of female neurosurgery residents increased from 12.7% to 19.3%and the percentage of ABNS certified female neurosurgeons increased from 5% to 12% between 2010 and 2020. The total female authorship in Neurosurgery and Journal of Neurosurgery increased from 12 to 16.5% between 2003 and 2018, however there was no increase in senior authorship. Women were more likely to be published as first author with a female senior author than with a male senior author (30.4% v 14.1%). Systemic barriers identified include wage inequity of 10-25%, rampant sexual harassment, and barriers regarding parental leave policies.

CONCLUSIONS:

We propose the following updated recommendations. Neurosurgical departments and societies should make targeted effort to retain women in academic neurosurgery in order to foster mentorship opportunities. There must be explicit policies regarding sexual harassment, compensation equity, and parental leave. Finally, we propose new benchmarks of women comprising 30% of residents by 2030, and 30% of practicing neurosurgeons by 2040.
832 MR-guided Focused Ultrasound Thalamotomy of the Central Lateral Nucleus for Neuropathic Pain: An Interim and Technical Analysis
Authors: Ahmed Abdul-Kareem , Guo Sijia , Melhem Elias , Gullapalli Rao , Eisenberg Howard , Gandhi Dheeraj
Published: March 2022

INTRODUCTION:

Neuropathic pain (NP) results from injury to the pain neuromatrix and is associated with loss of quality of life, increased health costs, and pain medication use. Thalamotomy of the central lateral nucleus (CLT) of the thalamus has demonstrated benefit in these patients.

METHODS:

Patients with 6 months or greater of symptoms and failed intervention for NP related to phantom limb pain, spinal cord injury, and spine surgery, eligible for MRgFUS treatment, were enrolled and treated with bilateral CLT. Baseline, and 1, 3, and 12 month brief pain inventory (BPI) and pain disability index (PDI) scores were collected. Treatment, radiographic, and outcome data were analyzed with t-tests and linear regression models.

RESULTS:

Eight patients (6M:2F) have been enrolled and treated to date. There have been no serious adverse events, and several patients experienced stereotactic frame-related pain which resolved. Seven tolerated bilateral CLT, one unilateral, totaling 15 ablated nuclei. Mean age was 53.9 years. By 3 months, BPI decreased by 56.3% (n=7, p=.002), PDI decreased by 41.2% (n=7, p=.016). Energy to reach 50 Celsius correlated with skull density ratio (SDR) (R2=.54 p=.038). SDR did not correlate with BPI or PDI improvement. For 15 nuclei, mean lesion volume was 150.4 mm³. Total lesion volume in each patient did not correlate with BPI or PDI improvement.

CONCLUSIONS:

MRgFUS bilateral CLT is safe for chronic NP, and has efficacy in reducing symptoms as measured by validated pain scales. As with other MRgFUS ablative interventions, SDR correlates with acoustic transmission through the skull, and lesion volume does not affect clinical outcome.
839 Techniques for Management and Avoidance of Ventriculo Artrial Shunt Distal Catheter Complications
Authors: Zervos Thomas , Kutschman Kenneth , Mansour Tarek R. , Frisoli Tiberio , Air Ellen L. , Schwalb Jason M.
Published: March 2022

INTRODUCTION:

Minimizing the risk of distal ventriculatrial (VA) shunt disconnection is particularly important due to the risk of catheter embolization. This rare event occurs in approximately 1.56% of implanted VA shunts. There are no clear treatment guidelines in the literature to help prevent and manage this complication. The use of a connector in the neck has been implicated in mechanical failures of ventriculoperitoneal (VP) shunts;2however, to the best of our knowledge, there was no literature describing disconnection and migration of distal VA shunt catheters due to use of a connector.

METHODS:

Clinical records for a single institution between 2010 and 2021 were reviewed for instances of distal catheter disconnection and migration.

RESULTS:

All three instances of distal disconnection were associated with use of a connector in the neck that resulted in fracture of the catheter due to repetitive sheering forces. In all three cases, the distal catheter was retrieved via an endovascular approach in conjunction with transesophageal echocardiography to assess for retrieval feasibility. An additional case is included where the distal catheter is abandoned due to adhesions and the patient was placed on anticoagulation.

CONCLUSIONS:

We recommend the avoidance of a straight connector when performing VA shunt placement. Catheter removal requires a multidisciplinary approach to best reduce risk of complications.
Η κριτική του Καρλ Πόππερ στις περί Πολιτείας αντιλήψεις του Πλάτωνος
Authors: Πατέλης Γεώργιος
Published: March 2022

Ο Αυστριακός φιλόσοφος Καρλ Πόππερ, βαθύτατα επηρεασμένος από την επικράτηση του ολοκληρωτισμού στην Ευρώπη πριν και κατά τον Β’ Παγκόσμιο Πόλεμο, επιχείρησε να ασκήσει κριτική σε αναγνωρισμένους στοχαστές, φιλοσοφικές θεωρήσεις των οποίων συμπέρανε ότι ταυτίζονταν με ιδεολογήματα ολοκληρωτικής φύσεως. Η κριτική του στην Πολιτεία του Πλάτωνος ως ένα έργο με τέτοιες αντιλήψεις, εχθρικές προς το άτομο και την αυτονομία του, προκάλεσε αίσθηση και ποικίλες αντιδράσεις μεταξύ των μελετητών. Στη διατριβή μου προσπάθησα να εντοπίσω και να αναδείξω τα κύρια σημεία της προαναφερθείσας κριτικής και να προβώ στην αξιολόγησή τους. Παρουσίασα επίσης τις επιστημονικές και πολιτικές ιδέες του Πόππερ που αποτέλεσαν πυλώνες της κριτικής του εναντίον του Πλάτωνος. Κατέληξα στο συμπέρασμα ότι η ποππεριανή κριτική ήταν υπέρ το δέον επιθετική και αυστηρή, ιδεολογικά επηρεασμένη, συχνά υποπίπτουσα σε παρερμηνείες. Ο Πόππερ δεν κατάφερε να πλήξει «τη γοητεία» του Πλάτωνος, ανέδειξε όμως κάποια σημεία που εγείρουν ερωτηματικά περί πλατωνικών απόψεων που εκφράζονται στην Πολιτεία. Παρά τις αδυναμίες της ποππεριανής κριτικής, σε γενικές γραμμές παρήχθη γόνιμος προβληματισμός που επεξέτεινε τους ερμηνευτικούς ορίζοντες στη μελέτη του Πλάτωνος.
Το αστυνομικό μυθιστόρημα ανάμεσα στην πραγματικότητα και τη φαντασία
Authors: Σκρεμμύδα Βασιλική-Αλεξάνδρα
Published: March 2022

Η παρούσα έρευνα έχει ως αντικείμενο τη μελέτη του αστυνομικού μυθιστορήματος και την εξέλιξή του μέσα από την εξέταση των έργων Ιταλών και Ελλήνων συγγραφέων αστυνομικής μυθιστορίας, ξεκινώντας από το κλασσικό αστυνομικό και καταλήγοντας στο αστυνομικό ρεπορτάζ και το μεσογειακό αστυνομικό μυθιστόρημα. Το είδος αυτό της λογοτεχνίας, που χαρακτηρίστηκε στην αρχή ως παραλογοτεχνία, κινείται μεταξύ φαντασίας και πραγματικότητας, εξετάζει δε το κακό που εισβάλλει στη ζωή του ανθρώπου, ανάλογα με το κοινωνικό πλαίσιο, την εποχή και την ιδιοσυγκρασία κάθε συγγραφέα. Πρόκειται για τη λογοτεχνία του κακού (la letteratura del male), όπου επικρατεί η βία, το έγκλημα, το μυστήριο, οι προσπάθειες για την ανακάλυψη των ενόχων και η απόδοση της δικαιοσύνης.Στο πρώτο μέρος της εργασίας εξετάσθηκε μέσα από τα μυθιστορήματα των Ιταλών συγγραφέων Leonardo Sciascia, Roberto Saviano, Elena Ferrante και Andrea Camilleri το οργανωμένο έγκλημα. Οι τέσσερις αυτοί συγγραφείς παρουσίασαν την ιταλική πραγματικότητα και το φαινόμενο της βίας σε σχέση με τις επικρατούσες κοινωνικοπολιτικές συνθήκες.Στο δεύτερο μέρος μελετήθηκαν οι Έλληνες εκπρόσωποι του μεσογειακού είδους Γιάννης Μαρής, Πέτρος Μάρκαρης, Θεόδωρος Μπενάκης και Χίλντα Παπαδημητρίου, αναλύθηκαν δε τα πλέον αντιπροσωπευτικά έργα της αστυνομικής μυθιστορίας τους σύμφωνα με το είδος, τον σκοπό και την τεχνική αφήγησης.Στο τρίτο μέρος πραγματοποιήθηκε μια μελέτη με συγκριτικό χαρακτήρα, που εστίασε στις ομοιότητες και τις διαφορές που εντοπίζονται ανάμεσα στους παραπάνω Ιταλούς και Έλληνες μυθιστοριογράφους και τα έργα τους, στα οποία επιδιώκεται η εξιχνίαση του εγκλήματος, η ανακάλυψη της αλήθειας και ο περιορισμός ή η εξάλειψη του κακού. Πρωταγωνιστεί ο ντεντέκτιβ – αστυνόμος, ενώ κάθε συγγραφέας μυεί τον αναγνώστη στις επικρατούσες εκάστοτε κοινωνικές συνθήκες, στη διαφορετικότητα του τόπου διαδραματισμού των γεγονότων και στους ανθρώπινους χαρακτήρες, στον ρόλο του γυναικείου στοιχείου στο έγκλημα και στη γαστρονομία, βασικό χαρακτηριστικό της μεσογειακής μυθιστορίας.
A reflection on participatory research methodologies in the light of the COVID-19 – lessons learnt from the European Research Project TRIPS
Authors: König Alexandra , Hatzakis Tally , Andrushevich Alexey (Aliaksei) , Hoogerwerf Evert-Jan , Vasconcelos Elvia , Launo Carolina , Alčiauskaitė Laura , Barbosa Steven , Andersen Kristina
Published: March 2022

The coronavirus disease (COVID-19) outbreak has had considerable impacts on research projects, particularly those adopting participatory approaches. This paper reflects on the methodological adaptations employed by the European research project TRIPS to facilitate co-design and open innovation practices towards the development of accessible mobility solutions. The article reports how the methods were adapted to facilitate participatory research with almost no physical meetings. In doing so, the paper presents the alternative ‘distanced-based’ participatory approaches employed to engage users with disabilities and institutional stakeholders in the transport ecosystem, like online workshops, social media content analysis, online surveys and peer-to-peer telephone interviews. Lessons learnt and practical guidelines for distance-based participatory research are presented and discussed with the aim of increasing resilience in the light of future changes.
Disentangling the Effects of Ad Tone on Voter Turnout and Candidate Choice in Presidential Elections
Authors: Gordon Brett R. , Lovett Mitchell J. , Luo Bowen , Reeder James C.
Published: March 2022

We study the effects of positive and negative advertising in presidential elections. We develop a model to disentangle these effects on voter turnout and candidate choice. The central empirical challenges are highly correlated and endogenous advertising quantities that are measured with error. To address these challenges, we construct a large set of potential instruments, including interactions with incumbency that we demonstrate provide the critical identifying variation, and apply machine-learning causal inference methods. Using data from the 2000 and 2004 U.S. presidential elections, we find that positive and negative ads play fundamentally different roles. Negative ads are more effective at driving relative candidate shares, whereas positive ads stimulate turnout. These results indicate that a candidate geographically targeting tone trades off local relative share gains and local increases in turnout for localities with a strong base. Counterfactual simulations, where the candidates adjust the quantity of positive and negative advertising while budgets remain fixed, indicate that ad tone alone can impact the outcome of close elections. Our analysis also provides potential explanations as to why past studies have produced mixed findings on both ad-tone and turnout effects.

This paper was accepted by Matthew Shum, marketing.

Supplemental Material: The data and online appendix are available at https://doi.org/10.1287/mnsc.2022.4347 .
"¡Si el bosque quemarás, poco me verás!" le dijo el ocelote al fuego
Authors: Muñoz-Belmont Sheyla Nallely , Esparza-Carlos Juan Pablo , Iñiguez-Dávalos Luis Ignacio , Alcántara-Concepción Pedro Camilo
Published: March 2022

Una antigua leyenda cuenta que el ocelote era de piel dorada y estaba enamorado de la Luna. Para él, nadie más podía brillar por lo que le exigió a un cometa, que se fuera. Pero el cometa, enojado, le lanzó piedras y fuego, causándole esas manchas oscuras que lo caracterizan.
Unsupervised monocular visual odometry via combining instance and RGB information
Authors: Yue Min , Fu Guangyuan , Wu Ming , Gu Hongyang , Yao Erliang
Published: March 2022

Unsupervised deep learning methods have made significant progress in monocular visual odometry (VO) tasks. However, due to the complexity of the real-world scene, learning the camera ego-motion from the RGB information of monocular images in an unsupervised way is still challenging. Existing methods mainly learn motion from the original RGB information, lacking higher-level input from scene understanding. Hence, this paper proposes an unsupervised monocular VO framework that combines the instance and RGB information, named combined information based (CI-VO). The proposed method includes two stages. First is obtaining the instance maps of the monocular images, without finetuning on the VO dataset. Then we obtain the combined information from the two types of information, which is input into the proposed combined information based pose estimation network, named CI-PoseNet, to estimate the relative pose of the camera. To make better use of the two types of information, we propose a fusion feature extraction network to extract the fused features from the combined information. Experiments on the KITTI odometry and KITTI raw dataset show that the proposed method has good performance in the camera pose estimation task, which exceeds the existing mainstream methods.
Threshold reduction of GHz-repetition-rate passive mode-locking by tapering the gain fiber
Authors: Ling Lin , Lin Wei , Wang Wenlong , Liang Zhaoheng , Chen Xuewen , Guo Yuankai , Wei Xiaoming , Yang Zhongmin
Published: March 2022

Passively mode-locked fiber lasers with GHz repetition rates have recently attracted significant attention in frontier research areas, including frequency-comb spectroscopy, coherent optical communication, photonic radar, micromachining, etc. In general, the threshold of passive mode-locking increases with the fundamental repetition rate, which is inversely proportional to the cavity length, and this sets a limit on the scalability of the fundamental repetition rate. To overcome this issue, here we propose to reduce the threshold of continuous-wave mode-locking (CWML) by precisely tapering the gain fiber, which can enhance the power density incident on the semiconductor saturable absorber mirror. Assisted by the analysis of guiding property, an experimental scheme is established for tapering standard Yb-doped fibers (125 µm cladding diameter), and tapered Yb-doped fibers with different waist diameters can be fabricated. Using a tapered Yb-doped gain fiber with waist cladding diameter of 90 µm, we are able to achieve CWML with a fundamental repetition rate of 3.3 GHz, and reduce its mode-locking threshold by 31%. More importantly, the optical spectrum of the CWML is found to be broadened with the waist diameter reduction of the gain fiber, which is beneficial for generating shorter transform-limited pulses. The efforts made in this work can provide a promising route to realize stable high-repetition-rate mode-locked fiber lasers with moderate levels of pump power.
Nonlinear reflectivity of AlGaInP SESAMs for mode locking in the red spectral range
Authors: Grossmann M. , Jetter M. , Michler P.
Published: March 2022

Mode-locked vertical external-cavity semiconductor lasers (VECSELs) are a wavelength-versatile laser that relies on a semiconductor saturable absorber mirror (SESAM) to initiate pulsed emission while simultaneously significantly influencing the pulse’s properties. A SESAM can be characterized using a nonlinear reflectivity setup, realized here in the red spectral range around 660 nm and achieving a moderate peak-to-peak variation of 0.17%. We use our home-built mode-locked VECSEL to reach a high maximum fluence up to 430 µJ/cm2 with strongly chirped 7.5 ps pulses. This allows the first-of-its-kind characterization of GaInP quantum well SESAMs, thereby revealing saturation fluences of 38 µJ/cm2 and 34 µJ/cm2 with modulation depths of 5% and 10.3% for SESAMs comprising one or two active quantum wells, respectively. For all structures, a nonsaturable loss of 2.8% is found and attributed to scattering loss.
Reconfigurable and real-time high-bandwidth Nyquist signal detection with low-bandwidth in silicon photonics
Authors: Misra Arijit , Kress Christian , Singh Karanveer , Meier Janosch , Schwabe Tobias , Preussler Stefan , Scheytt J. Christoph , Schneider Thomas
Published: March 2022

We demonstrate for the first time, to the best of our knowledge, reconfigurable and real-time orthogonal time-domain detection of a high-bandwidth Nyquist signal with a low-bandwidth silicon photonics Mach-Zehnder modulator based receiver. As the Nyquist signal has a rectangular bandwidth, it can be multiplexed in the wavelength domain without any guardband as a part of a Nyquist-WDM superchannel. These superchannels can be additionally multiplexed in space and polarization. Thus, the presented demonstration can open a new possibility for the detection of multidimensional parallel data signals with silicon photonics. No external pulse source is needed for the receiver, and frequency-time coherence is used to sample the incoming Nyquist signal with orthogonal sinc-shaped Nyquist pulse sequences. All parameters are completely tunable in the electrical domain. The feasibility of the scheme is demonstrated through a proof-of-concept experiment over the entire C-band (1530 nm–1560 nm), employing a 24 Gbaud Nyquist QPSK signal due to experimental constraints on the transmitter side electronics. However, the silicon Mach-Zehnder modulator with a 3-dB bandwidth of only 16 GHz can process Nyquist signals of 90 GHz optical bandwidth, suggesting a possibility to detect symbol rates up to 90 GBd in an integrated Nyquist receiver.
Switchable tri-function terahertz metasurface based on polarization vanadium dioxide and photosensitive silicon
Authors: Li Jiu-Sheng , Li Xiang-Jun
Published: March 2022

A terahertz switchable metasurface with the function of absorption and polarization conversion is proposed. It consists of metal pattern layer - dielectric layer - VO2 layer - dielectric layer - metal pattern layer, and the photosensitive silicon is embedded in the metal pattern. When VO2 is in insulated state, the metasurface behaves as a linear polarization converter. The polarization conversion rate (PCR) is more than 90% at two frequency bands of 1.64 THz ∼ 1.91 THz and 2.35 THz ∼ 2.75 THz. The polarization converter has good asymmetric transmission ability. Moreover, the polarization conversion performance can be dynamically controlled by changing the conductivity of the photosensitive silicon. When VO2 is in metallic state, the metasurface becomes a terahertz bidirectional absorber, which exhibits different absorption properties under TE and TM waves with the maximum absorptance reaching to 100%. In addition, the absorption of TE and TM terahertz waves can be controlled at the specific frequency by changing the conductivity of photosensitive silicon. We also explore the application of dynamic control of polarization waves in the near-field image display.
Partially pruned DNN coupled with parallel Monte-Carlo algorithm for path loss prediction in underwater wireless optical channels
Authors: Du Zihao , Ge Wenmin , Song Guangbin , Dai Yizhan , Zhang Yufan , Xiong Jianmin , Jia Bowen , Hua Yan , Ma Dongfang , Zhang Zejun , Xu Jing
Published: March 2022

In this paper, we propose a new approach to solve the radiative transfer equation (RTE) and determine the path loss for line-of-sight (LOS) propagation with laser diode sources in underwater wireless optical channels, which severely suffers from attenuation due to inevitable absorption and scattering. The scheme is based on an effective combination of Monte-Carlo (MC) simulation employed for dataset generation and a partially pruned deep neural network (PPDNN) utilized to predict the received optical power. First, a parallel MC algorithm is newly introduced and applied to speed up the dataset-generation process. Compared with the conventional single-step MC, the dataset-generation time of the parallel MC can be reduced by at least 95%. Meanwhile, a deep neural network (DNN) is partially pruned to acquire a compact structure and adopted to predict the path loss in three typical water types. The simulation results yield that the mean square errors (MSEs) between the predictive and the reference ones are all lower than 0.2, while the sparsity of the original DNN’s weights can be appropriately increased to 0.9, 0.7, and 0.5 for clear water, coastal water, and harbor water, respectively. Finally, the occupied storage space of the original DNN can be dramatically compressed by at least 40% with a small performance penalty. In view of this, the received optical power under certain parameters could be instantly obtained by employing the proposed PPDNN, which can effectively help design underwater wireless optical communication systems in future work.
Hybrid sensor based on a hollow square core fiber for temperature independent refractive index detection
Authors: Pereira Diana , Bierlich Jörg , Kobelke Jens , Ferreira Marta S.
Published: March 2022

In this work, a hybrid sensor based on a section of hollow square core fiber (HSCF) spliced between two single mode fibers is proposed for the measurement of refractive index of liquids. The sensor, with a length of a few millimeters, operates in a transmission configuration. Due to the HSCF inner geometry, two different interferometers are generated. The first, a Mach-Zehnder interferometer, is insensitive to the external refractive index, and presents a sensitivity to temperature of (29.2 ± 1.1) pm/°C. The second one, a cladding modal interferometer, is highly sensitive to the external refractive index. An experimental resolution of 1.0 × 10−4 was achieved for this component. Due to the different responses of each interferometer to the parameters under study, a compensation method was developed to attain refractive index measurements that are temperature independent. The proposed sensor can find applications in areas where refractive index measurements are required and the control of room temperature is a challenge, such as in the food and beverage industry, as well as in biochemical or biomedical industries.
Improving the tolerances in high-performance silicon photonics modulators
Authors: Cohen Roei Aviram , Amrani Ofer , Ruschin Shlomo
Published: March 2022

A racetrack-shaped modulator, based on Double Injection method, has been recently presented able to provide multiple response shapes and exhibiting enhanced robustness to deviations in parameters. Fabrication process deviations that influence sensitive ingredients of ring-based modulators such as the ring's waveguide, couplers, and heat that is generated in Silicon Photonics devices due to carrier transport, can degrade the modulator extinction-ratio (ER) and optical modulation depth (OMD). The sensitivity of the, so-called, PIR20 configuration (Parameters-Insensitive Response with ER of 20 dB) to fabrication and temperature deviations is analyzed in detail. Comparison to other known modulators based on either a ring, MZI or Fabry-Pérot resonators, reveals that the PIR20 device is considerably less sensitive to deviations of these types.
PLUS: Predicting cancer metastasis potential based on positive and unlabeled learning
Authors: Zhou Junyi , Lu Xiaoyu , Chang Wennan , Wan Changlin , Lu Xiongbin , Zhang Chi , Cao Sha
Published: March 2022

Metastatic cancer accounts for over 90% of all cancer deaths, and evaluations of metastasis potential are vital for minimizing the metastasis-associated mortality and achieving optimal clinical decision-making. Computational assessment of metastasis potential based on large-scale transcriptomic cancer data is challenging because metastasis events are not always clinically detectable. The under-diagnosis of metastasis events results in biased classification labels, and classification tools using biased labels may lead to inaccurate estimations of metastasis potential. This issue is further complicated by the unknown metastasis prevalence at the population level, the small number of confirmed metastasis cases, and the high dimensionality of the candidate molecular features. Our proposed algorithm, calledPositive and unlabeledLearning fromUnbalanced cases andSparse structures (PLUS), is the first to use a positive and unlabeled learning framework to account for the under-detection of metastasis events in building a classifier. PLUS is specifically tailored for studying metastasis that deals with the unbalanced instance allocation as well as unknown metastasis prevalence, which are not considered by other methods. PLUS achieves superior performance on synthetic datasets compared with other state-of-the-art methods. Application of PLUS to The Cancer Genome Atlas Pan-Cancer gene expression data generated metastasis potential predictions that show good agreement with the clinical follow-up data, in addition to predictive genes that have been validated by independent single-cell RNA-sequencing datasets.
‘We do not talk about it’: Engaging youth in Malawi to inform adaptation of a mental health literacy intervention
Authors: Jumbe Sandra , Nyali Joel , Simbeye Maryrose , Zakeyu Nelson , Motshewa Gase , Pulapa Subba Rao
Published: March 2022

Purpose

There is limited knowledge on how to tackle mental health problems among youth in Africa. Literature describing community engagement (CE) approaches in low/middle-income countries (LMICs) health research is sparse. CE with youth from LMICS can help steer and shape culturally relevant interventions for stigmatised topics like mental health, resulting in better healthcare experiences. We share our experience of engaging youth in Malawi through advocacy organisations to inform cultural adaptation of a mental health literacy intervention.

Methods

Young people were recruited using social media from universities and community youth organisations in Malawi to participate in focus group discussions to help culturally adapt content of an existing mental health literacy intervention. Nine online focus groups with 44 individuals were conducted. Discussions involved views and experiences of mental health, including impact of the coronavirus pandemic. Discussions were recorded, transcribed verbatim and analysed using content analysis.

Results

Transcript analyses revealed a vicious cycle of poverty and mental health problems for youth in Malawi. Four key themes were identified, 1) poverty-related socioeconomic and health challenges, 2) no one talks about mental health, 3) lacking mental health support and 4) relationship issues. These themes fed into one another within this vicious cycle which perpetually and negatively impacted their lives. The coronavirus pandemic worsened socioeconomic issues, health challenges, mental health and substance use issues, and burden on Malawi’s already weak mental health system.

Conclusion

Findings suggest increasing untreated mental health burden among Malawi’s youth. It highlights great need to address mental health literacy using existing community structures like educational settings to minimise burden on a weak health system. Online focus groups are an effective way of acquiring views from various young people in Malawi on mental health. This CE approach has grown our stakeholder network, strengthening potential for future CE activities and broader research dissemination.
PARA UMA TEORIA GERAL DA HISTÓRIA DAS IDEIAS JURÍDICAS AMBIENTAIS A PARTIR DA RACIONALIDADE DE ENRIQUE LEFF
Authors: Ferreira Maia Fernando Joaquim , Chagas Gomes Cárita
Published: March 2022

Contextualização do tema: a temática se insere na crítica à colonialidade do direito na América Latina, especificamente no direito ambiental. Esta colonialidade se assenta na incapacidade do mercado dialogar e internalizar o mundo dos direitos com os valores das comunidades campesinas, das populações tradicionais, indígenas, quilombolas e das massas urbanas, que formam o saber ambiental.Objetivos: a partir deste problema, o objetivo do trabalho é esboçar uma teoria geral da história das ideias jurídicas ambientais a partir da racionalidade de Enrique Leff.  Metodologia: a linha metodológica assume uma direção multidisciplinar, com o aporte da história das ideias, de efetivação do pensamento fundamental de Enrique Leff na história das ideias jurídicas a partir de uma simbiose entre o conceito de formação econômico-social em Karl Marx e Friedrich Engels, o conceito de racionalidade em Weber e o conceito de saber ambiental em Foucault.Resultados: a conclusão aponta que o objeto das ideias jurídicas ambientais pode ser apreendido, para pesquisa em história das ideias jurídicas, mediante a racionalidade ambiental. Além do mais, a racionalidade ambiental auxilia na detecção das contradições fundamentais e secundárias na relação jurídica ambiental e na diferenciação das várias etapas de desenvolvimento dessas contradições e dos seus fenômenos.
Lung Infection Affects Access to Treatment and Short-Term Outcome in Patients With Severe Alcohol-Related Hepatitis Treated With Corticosteroids
Authors: Ntandja Wandji Line Carolle , Ningarhari Massih , Lemaître Elise , Khaldi Marion , Saffers Pierre , Lollivier Julien , Lassailly Guillaume , Dharancy Sébastien , Mathurin Philippe , Louvet Alexandre
Published: March 2022

INTRODUCTION:

Severe alcohol-related hepatitis (AH) is associated with an increased risk of infection, but the impact of pneumonia has not been specifically analyzed in a specific cohort.

METHODS:

All patients admitted for severe AH between 2002 and 2020 were prospectively included. Systematic screening for infection was performed at admission and renewed in the case of clinical suspicion.

RESULTS:

We included 614 patients (60.4% men, mean age 49.9 years, median model for end-stage liver disease [MELD] 25.2, bilirubin 18.1 mg/dL), 202 (32.9%) with infections at admission (73 lung infections). Encephalopathy (P = 0.006), MELD score (P = 0.0002), and tobacco exposure (past vs never smokers: P = 0.002 or active vs past smokers: P = 0.005) were associated with lung infection at admission on multivariate analysis. Factors independently associated with death before steroid initiation were encephalopathy (P = 0.003), MELD score (P = 0.05), and especially lung infection (P < 0.0001). Thus, patients with a lung infection had a lower probability of receiving steroids than those with other infections and noninfected patients: 54.8 vs 88.4 vs 98.1% (P < 0.0001). One hundred forty-six of the 558 patients who received corticosteroids developed infection, including 57 (39.04%) pneumonias. The risk of respiratory and nonrespiratory infection was higher in nonresponders to steroids (Lille score ≥0.45) than in responders: 13% vs 7.6%, P = 0.03 and 27.9% vs 10.6%, P < 0.001, respectively. The variables independently associated with 3-month mortality after steroid initiation were lung infection (P = 0.004), nonresponse to steroids (P < 0.0001), MELD score (P = 0.0003), ascites (P = 0.003), and encephalopathy (P = 0.018), whereas nonrespiratory infections were not (P = 0.91).

DISCUSSION:

Lung infection is frequent during severe AH and influences mortality at admission and after steroid initiation. These results emphasize the need for specific management of lung infection during the course of AH.
The Influence of Investment, Debt, and Dividend Policies on the Stock Return of Shariah Compliant Companies in Indonesia (ISSI)
Authors: Haron Razali , Siraj Mukhtar Arif
Published: March 2022

This study aims to analyze the impact of investment, debt, and dividend policies on the stock return of the companies listed in the Indonesia Sharia Stock Index (ISSI) from 2016 up to 2020. The sample stocks used in this study covers all the shariah compliant companies that were consistently listed during the study period, involving 158 companies with 790 observations. The proxies of stock return are annualized stock return, Sharpe ratio, and Treynor ratio. Investment policy is represented by price earnings ratio (PER), debt policy by debt to asset ratio (DAR), and dividend policy by dividend yield (DY). The generalized method of moment (GMM) is a regression technique that is employed in this study. The regression model should pass the AR(2) and Hansen tests to avoid autocorrelation and validity issues. This study provides important evidence that investment policy positively affects stock return (annualized stock return and Treynor ratio). In contrast, investment policy negatively affects the Sharpe ratio. Furthermore, there is a significant negative relationship between debt policy and the Sharpe ratio. Lastly, dividend policy is reported to significantly influence stock return, positive with Treynor ratio, while negative with stock return (annualized). The study relates its findings to the relevant theories involving the trade-off, signalling, and the bird in the hand theories.
Study of Stopping Power of Electron in Human Tissues
Authors: Ali Niran Salim
Published: March 2022

Charged particles lose energy by nuclear interactions during their passing in material are very significant and useful especially in nuclear therapy. We used Bethe-Bloch equation programmed with Matlab and compared the results with E-star program. There are calculated total stopping power (collisional and radiative stopping power) for electron in tissues (Brain and Lung) by considering that each tissue consists of several elements; the total stopping power was measured for those elements within the energy range from 0.01-1000 MeV, taking into account the density correction used in the stopping power calculation. Results are presented and compared with the latest published data.
Extractive summarization of Malayalam documents using latent Dirichlet allocation: An experience
Authors: Kondath Manju , Suseelan David Peter , Idicula Sumam Mary
Published: March 2022

Automatic text summarization (ATS) extracts information from a source text and presents it to the user in a condensed form while preserving its primary content. Many text summarization approaches have been investigated in the literature for highly resourced languages. At the same time, ATS is a complicated and challenging task for under-resourced languages like Malayalam. The lack of a standard corpus and enough processing tools are challenges when it comes to language processing. In the absence of a standard corpus, we have developed a dataset consisting of Malayalam news articles. This article proposes an extractive topic modeling-based multi-document text summarization approach for Malayalam news documents. We first cluster the contents based on latent topics identified using the latent Dirichlet allocation topic modeling technique. Then by adopting vector space model, the topic vector and sentence vector of the given document are generated. According to the relevant status value, sentences are ranked between the document’s topic and sentence vectors. The summary obtained is optimized for non-redundancy. Evaluation results on Malayalam news articles show that the summary generated by the proposed method is closer to the human-generated summaries than the existing text summarization methods.
Incorporación del uso tecnológico en la política pública de seguridad ciudadana en Medellín
Authors: Díaz Guarneros Jorge David , Díaz Arenas Pedro Felipe
Published: March 2022

Este artículo, de alcance exploratorio, busca responder los siguientes cuestionamientos: ¿de qué manera el uso tecnológico ha ido tomando relevancia en las políticas públicas de seguridad ciudadana en Medellín; y a qué obedece su importancia para las instituciones de seguridad? Así mismo, busca analizar la incorporación del uso tecnológico en la política de seguridad de Medellín como un elemento transversal; esto mediante una propuesta interpretativa y de triangulación de información, mediante la cual se consultaron documentos del gobierno local, notas periodísticas y un par de entrevistas. La información analizada permite observar un creciente interés en el uso tecnológico en la ciudad que se incorpora a las políticas públicas de seguridad ciudadana, con el diseño de un modelo de gestión de la ciudad más integral y no dejando de señalar de igual forma algunos posibles efectos adversos de este uso tecnológico.