bluuebunny/crossref_metadata_2025 huggingface dataset:
The Abra sedimentary-hosted Pb-Ag-Cu-Au deposit, Western Australia: A geophysical case study
Authors: Stannard David , Meyers Jayson , Scopel Angelo
Published: February 2021

Abra is a high-grade sedimentary-hosted Pb deposit located in the Paleoproterozoic Edmund Basin in Western Australia. Mineralization is blind, with the top of the deposit occurring 250 m beneath the land surface. The deposit consists of a stratiform apron of Pb-Ag-Ba mineralization in laminated iron-oxide- and barite-altered dolomite and siltstone, which overlies a feeder zone of chlorite-altered, brecciated, and veined carbonatic siltstone that contains Pb-Ag mineralization in the core that transitions to Pb-Cu and Cu-Au at depth. Abra is characterized by discrete geophysical anomaly responses in magnetic, gravity, time-domain electromagnetic (TDEM), and induced polarization survey data. A +450 nT magnetic anomaly is caused by magnetite in the lower stratiform zone. Dense galena, barite, dolomite, and iron-oxide mineralization in the apron and galena in the feeder zone is surrounded by lower-density sedimentary host rocks, which results in a +1 mGal gravity anomaly. Airborne, ground, and downhole TDEM surveying resolved known mineralization as weak electromagnetic conductor responses, and petrophysical testing on core samples shows that this is caused by galena. Pole-dipole-induced polarization surveying resolved a +20 ms chargeability anomaly on the southern flank of the deposit. This chargeable anomaly response is related to disseminated galena, pyrite, chalcopyrite, and alteration. Joint audiomagnetotelluric-magnetotelluric 2D inverted data sections resolved Abra as a broad weakly conductive anomaly. Weak conductor responses associated with Abra were also resolved in 2D and 3D inversion modeling of airborne Z-axis tipper electromagnetic data. 2D seismic reflection surveying resolved Abra as strong flat-lying seismic reflectors, which are bounded and offset by faults and surrounded by a seismically bland zone. The seismic reflections are related to significant density contrasts between high-density stratiform mineralization that is in contact with low-density sedimentary host rocks, as the mineralization and host rocks have similar seismic velocities. Passive seismic horizontal to vertical spectral ratio surveying resolved the top of the deposit as a subtle layer sitting below a flat impedance contrast horizon that is interpreted as weathered siltstone on top of diagenetically cemented siltstone.
Cervix Cancer in Sub-Saharan Africa: An Assessment of Cervical Cancer Management
Authors: Burt Lindsay M. , McCormak Mary , Lecuru Fabrice , Kanyike Daniel M. , Bvochora-Nsingo Memory , Ndlovu Ntokozo , Scott Aba A. , Anorlu Rose I. , Sharma Vinay , Plante Marie , Nyongesa Catherine , Tigeneh Wondemagegnehu , Fakie Nazia , Suneja Gita , Gaffney David K.
Published: February 2021

PURPOSE

Underdeveloped nations carry the burden of most cervical cancer, yet access to adequate treatment can be challenging. This report assesses the current management of cervical cancer in sub-Saharan Africa to better understand the needs of underdeveloped nations in managing cervical cancer.

METHODS

A pre- and postsurvey was sent to all centers participating in the Cervical Cancer Research Network's 4th annual symposium. The pre- and postsurvey evaluated human papillomavirus and HIV screening, resources available for workup and/or treatment, treatment logistics, outcomes, and enrollment on clinical trials. Descriptive analyses were performed on survey responses.

RESULTS

Twenty-nine centers from 12 sub-Saharan countries saw approximately 300 new cases of cervical cancer yearly. Of the countries surveyed, 55% of countries had a human papillomavirus vaccination program and 30% (range, 0%-65%) of women in each region were estimated to have participated in a cervical cancer screening program. In the workup of patients, 43% of centers had the ability to obtain a positron emission tomography and computed tomography scan and 79% had magnetic resonance imaging capabilities. When performing surgery, 88% of those centers had a surgeon with an expertise in performing oncological surgeries. Radiation therapy was available at 96% of the centers surveyed, and chemotherapy was available in 86% of centers. Clinical trials were open at 4% of centers.

CONCLUSION

There have been significant advancements being made in screening, workup, and management of patients with cervical cancer in sub-Saharan Africa; yet, improvement is still needed. Enrollment in clinical trials remains a struggle. Participants would like to enroll patients on clinical trials with Cervical Cancer Research Network's continuous support.
Expected Medium- and Long-Term Impact of the COVID-19 Outbreak in Oncology
Authors: Onesti Concetta Elisa , Tagliamento Marco , Curigliano Giuseppe , Harbeck Nadia , Bartsch Rupert , Wildiers Hans , Tjan-Heijnen Vivianne , Martin Miguel , Rottey Sylvie , Generali Daniele , Campone Mario , Cristofanilli Massimo , Pusztai Lajos , Peeters Marc , Berchem Guy , Cortes Javier , Ruhstaller Thomas , Ciruelos Eva , Rugo Hope S. , Jerusalem Guy
Published: February 2021

PURPOSE

The COVID-19 pandemic has affected healthcare systems globally, leading to reorganization of medical activities. We performed an international survey aimed to investigate the medium- and long-term impact on oncology units.

MATERIALS AND METHODS

An 82-item survey was distributed from June 17 to July 14, 2020 among medical oncologists worldwide.

RESULTS

One hundred nine medical oncologists from 18 countries in Europe (n = 93), United States (n = 5), and Latin America (n = 11) answered the survey. A systematic tracing of COVID-19–positive patients was continued in the postacute phase by 77.1% of the centers; 64.2% of the respondents participated in a local registry and 56% in international or national registries of infected patients. Treatment adaptations were introduced, and surgery was the most affected modality being delayed or canceled in more than 10% of patients in 34% of the centers, whereas early cessation of palliative treatment was reported in 32.1% of the centers; 64.2% of respondents reported paying attention to avoid undertreatments. The use of telemedicine has been largely increased. Similarly, virtual tools are increasingly used particularly for medical education and international or national or multidisciplinary meetings. 60.6% of the participants reduced clinical activity, and 28.4% compensated by increasing their research activity. Significant reduction of clinical trial activities is expected in 37% of centers this year. The well-being of healthcare staff would not recover by the end of the year according to 18% of the participants.

CONCLUSION

The COVID-19 outbreak has had a major impact on oncologic activity, which will persist in the future, irrespective of geographical areas.
Open-Label, Single-Arm Phase II Study of Pembrolizumab Monotherapy as First-Line Therapy in Patients With Advanced Clear Cell Renal Cell Carcinoma
Authors: McDermott David F. , Lee Jae-Lyun , Bjarnason Georg A. , Larkin James M. G. , Gafanov Rustem A. , Kochenderfer Mark D. , Jensen Niels Viggo , Donskov Frede , Malik Jahangeer , Poprach Alexandr , Tykodi Scott S. , Alonso-Gordoa Teresa , Cho Daniel C. , Geertsen Poul F. , Climent Duran Miguel Angel , DiSimone Christopher , Silverman Rachel Kloss , Perini Rodolfo F. , Schloss Charles , Atkins Michael B.
Published: February 2021

PURPOSE

Pembrolizumab, a programmed death 1 inhibitor, demonstrated promising single-agent activity in untreated patients with various cancer types. The phase II KEYNOTE-427 study evaluated efficacy and safety of single-agent pembrolizumab in treatment-naive patients with advanced clear cell renal cell carcinoma (ccRCC; cohort A) and advanced non-ccRCC (cohort B). Results of cohort A are reported.

METHODS

In this open-label, single-arm phase II study, patients with advanced ccRCC received pembrolizumab 200 mg every 3 weeks for ≤ 24 months. The primary end point was objective response rate by RECIST, version 1.1.

RESULTS

In the total population (N = 110), median time from enrollment to data cutoff was 35.9 (range, 29.5-40.3) months. Objective response rate was 36.4% with four (3.6%) complete responses and 36 (32.7%) partial responses; disease control rate was 58.2% (95% CI, 48.4 to 67.5). Most patients (68.2%) had a decrease in target lesions, including 30.9% with a reduction ≥ 60%. Median duration of response was 18.9 (range, 2.3-37.6+) months; 64.1% of responders had a response ≥ 12 months (Kaplan-Meier). Median progression-free survival was 7.1 months (95% CI, 5.6 to 11.0). Median overall survival was not reached; 12-month and 24-month overall survival rates were 88.2% and 70.8%, respectively. Durable responses were observed across all International Metastatic RCC Database Consortium categories. Grade 3-5 treatment-related adverse events were reported in 30.0% of patients, of which colitis and diarrhea were most frequent.

CONCLUSION

Single-agent pembrolizumab showed promising antitumor activity as a first-line treatment in patients with advanced ccRCC, with durable responses across International Metastatic RCC Database Consortium categories. Safety and tolerability profile of pembrolizumab monotherapy was comparable to what has been previously described in other tumor types.
Nicotinamide Riboside Enhances In Vitro Beta-adrenergic Brown Adipose Tissue Activity in Humans
Authors: Nascimento Emmani B M , Moonen Michiel P B , Remie Carlijn M E , Gariani Karim , Jörgensen Johanna A , Schaart Gert , Hoeks Joris , Auwerx Johan , van Marken Lichtenbelt Wouter D , Schrauwen Patrick
Published: February 2021

Context

Elevating nicotinamide adenine dinucleotide (NAD+) levels systemically improves metabolic health, which can be accomplished via nicotinamide riboside (NR). Previously, it was demonstrated that NR supplementation in high-fat-diet (HFD)-fed mice decreased weight gain, normalized glucose metabolism, and enhanced cold tolerance.

Objective

Because brown adipose tissue (BAT) is a major source of thermogenesis, we hypothesize that NR stimulates BAT in mice and humans.

Design and intervention

HFD-fed C56BL/6J mice were supplemented with 400 mg/kg/day NR for 4 weeks and subsequently exposed to cold. In vitro primary adipocytes derived from human BAT biopsies were pretreated with 50 µM or 500 µM NR before measuring mitochondrial uncoupling. Human volunteers (45-65 years; body mass index, 27-35 kg/m2) were supplemented with 1000 mg/day NR for 6 weeks to determine whether BAT activity increased, as measured by [18F]FDG uptake via positron emission tomography-computed tomography (randomized, double blinded, placebo-controlled, crossover study with NR supplementation).

Results

NR supplementation in HFD-fed mice decreased adipocyte cell size in BAT. Cold exposure further decreased adipocyte cell size on top of that achieved by NR alone independent of ex vivo lipolysis. In adipocytes derived from human BAT, NR enhanced in vitro norepinephrine-stimulated mitochondrial uncoupling. However, NR supplementation in human volunteers did not alter BAT activity or cold-induced thermogenesis.

Conclusions

NR stimulates in vitro human BAT but not in vivo BAT in humans. Our research demonstrates the need for further translational research to better understand the differences in NAD+ metabolism in mouse and human.
Dyslipidemia, Insulin Resistance, Ectopic Lipid Accumulation, and Vascular Function in Resistance to Thyroid Hormone β
Authors: Moran Carla , McEniery Carmel M , Schoenmakers Nadia , Mitchell Catherine , Sleigh Alison , Watson Laura , Lyons Greta , Burling Keith , Barker Peter , Chatterjee Krishna
Published: February 2021

Purpose

In resistance to thyroid hormone due to mutations in thyroid hormone receptor β, peripheral tissues are variably refractory to the action of circulating thyroid hormones. We evaluated parameters contributing to atherosclerotic risk in this disorder.

Methods

We measured low-density lipoprotein cholesterol (LDL-C), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), nonesterified fatty acids (NEFA), intrahepatic lipid (IHL) and intramyocellular lipid (IMCL), Homeostasis-model assessment of insulin resistance (HOMA-IR), augmentation index (AIx) and pulse wave velocity (PWV), flow-mediated dilatation, and carotid intima-media thickness (cIMT) in an unselected, genetically confirmed cohort of adult RTHβ patients (n = 27-77) and compared these with measurements in healthy subjects (up to n = 100) and thyrotoxic patients (n = 40).

Results

Resistance to thyroid hormone beta (RTHβ) patients exhibited higher LDL-C (P = 0.008) and TG (P = 0.002) and lower HDL-C concentrations (P = 0.015 × 10–2) than control subjects, with LDL-C being higher than in thyrotoxic patients with comparable hyperthyroxinemia. Proprotein convertase subtilisin/kexin 9 (P = 0.002) and apolipoprotein B (P = 0.0009) levels were reduced in thyrotoxic patients but not lower in RTHβ patients or control subjects. Intrahepatic lipid (P = 0.02 × 10–4), IMCL (P = 0.002), HOMA-IR (P = 0.01 × 10–2), and NEFA (P = 0.04 × 10–6) were significantly higher in RTHβ patients than control subjects. Flow-mediated dilatation was increased (P = 0.04) but cIMT (P = 0.71), PWV P = 0.81), and AIx (P = 0.95) were unaltered in RTHβ patients.

Conclusions

We have documented mixed dyslipidemia with hepatic and IMCL accumulation in RTHβ, suggesting that surveillance for these metabolic abnormalities is warranted. How they combine with enhanced endothelial function and unaltered vessel wall thickness and compliance to determine overall cardiometabolic risk in this disorder remains to be defined.
Synthesis of Highly Fluorescent Cationic Chlorophyll-a Derivatives Possessing a p-Aminopyridinio Group at the 31-Position
Authors: Ogasawara Shin , Takahashi Tatsuya , Kitagawa Yuichi , Tamiaki Hitoshi
Published: February 2021

p-Aminopyridines were oxidatively substituted at the C31-position of methyl pyropheophorbide-a, a chlorophyll-a derivative. The electron-donating p-dimethylamino groups induced silver metallation during the substitution and inhibited the electron-transfer quenching of fluorescence emission in the metal-free C31-cationic pyridinio adducts prepared by the acidic demetallation of the initially isolated Ag-chlorins.
The Sensitivity of Housing Demand to Financing Conditions: Evidence from a Survey
Authors: Fuster Andreas , Zafar Basit
Published: February 2021

Measuring the sensitivity of housing demand to mortgage rates and available leverage is challenging because there is generally no exogenous variation in these variables. This paper circumvents this issue by designing a strategic survey in which respondents report their willingness to pay (WTP) for a home under different financing scenarios. Relaxation of down payment constraints or an exogenous increase in nonhousing wealth has large effects on WTP, especially for poorer and more credit-constrained households. However, changing the mortgage rate has only moderate effects on WTP. These findings have implications for theoretical models of house price determination and for policy. (JEL G21, G51, R21, R38)
Rising Intergenerational Income Persistence in China
Authors: Fan Yi , Yi Junjian , Zhang Junsen
Published: February 2021

This paper documents an increasing intergenerational income persistence in China since economic reforms were introduced in 1979. The intergenerational income elasticity increases from 0.390 for the 1970–1980 birth cohort to 0.442 for the 1981–1988 birth cohort; this increase is more evident among urban and coastal residents than rural and inland residents. We also explore how changes in intergenerational income persistence is correlated with market reforms, economic development, and policy changes. (JEL J62, O15, O18, P25, P36)
Parental Support, Savings, and Student Loan Repayment
Authors: Lochner Lance , Stinebrickner Todd , Suleymanoglu Utku
Published: February 2021

Using unique survey and administrative data from Canada, we document that parental support and personal savings substantially reduce student loan repayment problems. Developing a model of student borrowing and repayment, we show that nonmonetary costs of applying for income-based repayment assistance are critical to understanding our findings. Furthermore, we show that eliminating these costs may be inefficient. Empirically, we show that expanding Canada’s Repayment Assistance Plan to automatically cover all borrowers could reduce program revenue by half over early repayment years. Finally, we show how student loan programs can be more efficiently designed. (JEL G51, I22, I23, I28)
The Long-Run Effects of a Public Policy on Alcohol Tastes and Mortality
Authors: Kueng Lorenz , Yakovlev Evgeny
Published: February 2021

We study the long-run effects of Russia’s anti-alcohol campaign, which dramatically altered the relative supply of hard and light alcohol in the late 1980s. We find that this policy shifted young men’s long-run preferences from hard to light alcohol decades later, and we estimate the age at which consumers form their tastes. We show that the large beer market expansion in the late 1990s had similar effects on young consumers’ tastes, while older consumers’ tastes remained largely unchanged. We then link these long-run changes in alcohol consumption patterns to changes in male mortality. The shift from hard to light alcohol reduced incidences of binge drinking substantially, leading to fewer alcohol-related deaths. We conclude that the resulting large cohort differences in current alcohol consumption shares explain a significant part of the recent decrease in male mortality. Simulations suggest that mortality will continue to decrease by another 23 percent over the next 20 years due to persistent changes in consumer tastes. Program impact evaluations that focus only on contemporaneous effects can therefore severely underestimate the total effect of such public policies that change preferences for goods. (JEL D12, H25, H31, I12, I18, L66, P36)
Relative Prices and Climate Policy: How the Scarcity of Nonmarket Goods Drives Policy Evaluation
Authors: Drupp Moritz A. , Hänsel Martin C.
Published: February 2021

Climate change not only impacts production and market consumption but also the relative scarcity of nonmarket goods, such as environmental amenities. We study fundamental drivers of the resulting relative price changes, their potential magnitude, and their implications for climate policy in Nordhaus’s Dynamic Integrated Climate-Economy (DICE) model, thereby addressing one of its key criticisms. We propose plausible ranges for these relative prices changes based on best available evidence. Our central calibration reveals that accounting for relative prices is equivalent to decreasing pure time preference by 0.6 percentage points and leads to a more than 50 percent higher social cost of carbon. (JEL D61, H43, Q51, Q54, Q58)
A pilot study on lung cancer detection based on regional metabolic activity distribution in digital low-dose 18F-FDG PET
Authors: Messerli Michael , Muehlematter Urs J. , Fassbind Saskia , Franzen Daniel , Ferraro Daniela A. , Huellner Martin W. , Treyer Valerie , Curioni-Fontecedro Alessandra , Burger Irene A.
Published: February 2021

Objectives

To investigate the potential of automatic lung cancer detection on submillisievert dose 18F-fludeoxyglucose (18F-FDG) scans using different positron emission tomography (PET) parameters, as a primary step towards a potential new indication for 18F-FDG PET in lung cancer screening.

Methods

We performed a retrospective cohort analysis with 83 patients referred for 18F-FDG PET/CT, including of 34 patients with histology-proven lung cancer and 49 patients without lung disease. Aside clinical standard PET images (PET100%) two additional low-dose PET reconstructions were generated, using only 15 s and 5 s of the 150 s list mode raw data of the full-dose PET, corresponding to 10% and 3.3% of the original 18F-FDG activity. The lungs were subdivided into three segments on each side, and each segment was classified as normal or containing cancer. The following standardized uptake values (SUVs) were extracted from PET per lung segment: SUVmean, SUVhot5, SUVmedian, SUVstd and SUVtotal. A multivariate linear regression model was used and cross-validated. The accuracy for lung cancer detection was tested with receiver operating characteristics analysis and T-statistics was used to calculate the weight of each parameter.

Results

The T-statistics showed that SUVstd was the most important discriminative factor for lung cancer detection. The multivariate model achieved an area under the curve of 0.97 for full-dose PET, 0.85 for PET10% with PET3.3% reconstructions resulting in a still high sensitivity the PET10% reconstruction of 80%.

Conclusion

This pilot study indicates that segment-based, quantitative PET parameters of low-dose PET reconstructions could be used to automatically detect lung cancer with high sensitivity.

Advances in knowledge

Automated assessment of PET parameters in low-dose PET may aid for an early detection of lung cancer.
Diagnosis and management of hemorrhagic complications of percutaneous transhepatic biliary drainage: a primer for residents
Authors: Pulappadi Vishnu Prasad , Srivastava Deep Narayan , Madhusudhan Kumble Seetharama
Published: February 2021

Hemorrhagic complications are uncommon after percutaneous transhepatic biliary drainage. The presenting features include bleeding through or around the drainage catheter, hematemesis or melena. Diagnosis requires cholangiography, CT angiography or conventional angiography. Minor venous hemorrhage is managed by catheter repositioning, clamping or upgrading to a larger bore catheter. Major vascular injuries require percutaneous or endovascular procedures like embolization or stenting. A complete knowledge of these complications will direct the interventional radiologist to take adequate precautions to reduce their incidence and necessary steps in their management. This review presents and discusses various hemorrhagic complications occurring after percutaneous transhepatic biliary drainage along with their treatment options and suggests a detailed algorithm.
Multiparametric transvaginal ultrasound in the diagnosis of endometrial cancer in post-menopausal bleeding: diagnostic performance of a transvaginal algorithm and reproducibility amongst less experienced observers
Authors: Abdalla Shimaa , Abou-Taleb Hisham , Badary Dalia M. , Ali Wageeh A.
Published: February 2021

Objective:

(a) To comparatively evaluate the performance of grayscale ultrasound features, power Doppler (PD) blood flow characteristics, and gel infusion sonography (GIS) in diagnosing endometrial cancer during real-time examination, (b) to compare the performance of real-time diagnosis of endometrial cancer by experienced observers with offline analysis by blinded observers using similar sonographic criteria during review of cine loop clips.

Methods:

152 females with post-menopausal bleeding (PMB) had ET ≥ 4 mm at first-line ultrasound were included. Two experienced radiologists evaluated endometrial patterns at real-time evaluation (grayscale ultrasound, PD, and GIS), then examinations were stored as video clips for later evaluation by two less-experienced radiologists. The reference standard was hysteroscopy (HY) and/or hysterectomy with the histopathological examination. The area under (AUC) the receiver operating characteristic (ROC) curve was calculated to assess the diagnostic performance for the prediction of endometrial cancer.

Results:

Among 152 females with ET ≥ 4 mm at first line TVUS, 88 (57.9%) patients had endometrial cancer on final pathologic analysis. Real-time ultrasound criteria (ET ≥ 5 mm with the presence of irregular branching endometrial blood vessels or multiple vessels crossing EM or areas with densely packed color-splash vessels with non-intact or interrupted EMJ at the grayscale ultrasound and/or GIS) correctly diagnosed 95% of endometrial cancers with 92% diagnostic efficiency.

There is comparable accuracy of real-time evaluation (96%) and offline analysis (92%) after the exclusion of poor quality videos from the analysis. The diagnostic criteria showed good to an excellent agreement between real-time ultrasound and offline analysis.

Conclusion:

When real-time ultrasound is performed with good technique, utilizing multiple parameters, it is possible to diagnose endometrial cancer with a high degree of accuracy and reproducibility.

Advances in knowledge:

when real-time ultrasound is performed with good technique, utilizing multiple parameters, it is possible to diagnose endometrial cancer with a high degree of accuracy and reproducibility.
Antibiotic resistance pattern and frequency of some beta lactamase genes in Klebsiella pneumoniae isolated from raw milk samples in Iran
Authors: ENFERAD E. , MAHDAVI S.
Published: February 2021

Klebsiella pneumoniae have become an important cause of mastitis in dairy cows. Resistance to beta lactam antibiotics resulted from beta lactamases enzyme production. The aim of this study was to investigate the antibiotic resistance pattern and frequency of some beta lactamase genes in Klebsiella pneumoniae isolated from raw milk samples in Iran. 200 raw cow milk samples were collected from different villages of north west of Iran. The samples were cultured and biochemical tests were performed for phenotypic diagnosis. Then, antibiotic resistance pattern was determined by antibiogram test. Finally, the presence of CTX, SHV and TEM genes in Klebsiella pneumoniae isolates was found by PCR method. Of total 200 raw cow milk samples, 80 samples (40%) contained Klebsiella pneumoniae. The frequency of CTX, SHV and TEM genes in Klebsiella pneumoniae isolates was 50 (62.5%), 34 (42.5%) and 70 (87.5%), respectively. 14 Klebsiella pneumoniae isolates (17.5%) possessed all three intended genes simultaneously. All strains of Klebsiella pneumoniae (100%) were resistant to ampicillin. The most strains were resistant to ceftriaxone (75%), gentamicin (70%) and nitrofurantoin (70%). 4 Klebsiella pneumoniae strains (5%) were resistant to all of tested antibiotics. The results showed high frequency of ESBLs and antibiotic resistance in Klebsiella pneumonia samples isolated from raw milk. It may occur exchange of resistance genes within and across species and with commensal bacteria of the human and animals.
Preliminares
Authors: Olásolo Alonso Hector
Published: February 2021

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On the Learning Benefits of Resource Flexibility
Authors: Chod Jiri , Markakis Mihalis G. , Trichakis Nikolaos
Published: February 2021

Resource flexibility, arguably among the most celebrated operational concepts, is known to provide firms facing demand uncertainty with such benefits as risk pooling, revenue-maximization optionality, and operational hedging. In this paper, we uncover a heretofore unknown benefit: we establish that resource flexibility facilitates learning the demand when the latter is censored, which could, in turn, enable firms to make better-informed future operational decisions, thereby increasing profitability. Further, we quantify these learning benefits of flexibility and find that they could be of the same order of magnitude as the extensively studied risk-pooling benefits of flexibility. This suggests that flexibility’s learning benefits could be a first-order consideration and that extant theories, which view flexibility only as the ability to act ex post, could be underestimating its true value when learning the demand is desirable, for example, when it enables managers to make better ex ante capacity, assortment, or pricing decisions in future periods.

This paper was accepted by Vishal Gaur, operations management.
When Reinforcing Processes Generate an Outcome-Quality Dip
Authors: Denrell Jerker , Liu Chengwei
Published: February 2021

When does market success indicate superior merit? We show that when consumer choices between products with equal prices depend on quality but also on past popularity, more popular products are not necessarily of higher quality. Rather, a medium level of popularity may be associated with lower quality than lower levels of popularity. Using a formal model, we show that this kind of nonmonotonic association occurs when reinforcing processes are strong. More generally, a dip can occur when outcomes depend on both quality and resources and the latter are allocated bimodally, with some being given a lot of resources and most receiving little. Empirically, we illustrate that such a dip occurs in the association between movie theater sales and ratings. The presence of a dip in the outcome-quality association complicates learning from market outcomes and evaluation of individuals and new ventures, challenges the legitimacy of stratification systems, and creates opportunities for sophisticated evaluators who understand the dip.
Ethnic health inequalities in the UK's maternity services: a systematic literature review
Authors: Khan Zahra
Published: February 2021

Background

Black, Asian, and minority ethnic (BAME) women have significantly higher morbidity and mortality rates in the UK as well as poorer experiences of care. To date, a systematic literature review has not been undertaken in the UK to explore ethnicity based health inequalities.

Aim

To explore the maternal health inequalities encountered by BAME women in the UK in relation to their experiences and use of services.

Method

A systematic literature search was conducted via five databases (PubMed, MEDLINE, CINAHL, MIDIRS and BNI). Inclusion-exclusion criterion and a keyword strategy were implemented to screen for literature published between 2013–2018.

Findings

A total of eight studies with various ethnicities and geographical locations were included. Five themes emerged following thematic analysis: communication, midwife-woman relationship, healthcare services and systems, culture and social needs.

Conclusion

The review identified consistency within and across the five themes. Maternity services and systems is a predominant theme that has a residual effect on the remaining four themes.
Using subpalpebral lavage systems to deliver ocular drugs to 4 fractious dogs
Authors: Rushton James Oliver
Published: February 2021

The use of subpalpebral lavage systems is commonplace in equine ophthalmology and its use has also been described in humans, llamas and a harbour seal. However, reports of this drug delivery technique in dogs are lacking. This case study describes four cases of corneal ulceration in fractious dogs, where a subpalpebral lavage system was used to apply topical medication. Clinical presentation, surgical techniques and the outcomes are described. All dogs were successfully treated by their owners using this technique, and no major complications were reported.
MPFL Reconstruction Using Quadriceps Tendon Graft - Our Five Years Expirience
Authors: Marinkovic Jugoslav , Radunovic Aleksandar , Vranic Vladimir , Stasa Munitlak
Published: February 2021

The primary traumatic luxation of the knee cup affects the general population with an incidence of 5.8 per 100,000 (3), while in the younger age group (10-17 years) it goes up to 29 per 100,000. Most patients will not have instability after non-operative treatment, while repeated luxation will occur in 15 to 44% of cases. The use of the quadriceps tendon for medial patelofemoral ligament (MPFL) reconstruction is a method described independently by Steensen et al. and Noyes and Albright. Today have more and more supporters because of their simplicity, minimal trauma and good postoperative results. Reconstruction of MPFL with quadriceps tendon (QT) for recurrent patellofemoral instability started in our Clinic in 2014. Indications for surgery were patients who have had clear clinical and radiological signs of instability, tibial tubercle-trochlear groove distance (TT-TG) < 20 mm, dysplastic trochlea grade A according to the Dejour classification. For clinical testing we used apprehension and Veselko's test. In our clinic 22 patients were operated in past fifth years. This study shows result of 17 patients. We noticed a significant improvement in patients in daily activities (instability, swelling, pain, kneeling, squatting, climbing stairs). All patients had full range of motion after approximately 3 months. The initial Lyscholm score value was 69.2 ± 6.4 while after two years 88.3 ± 3,2. Our observation shows that MPFL reconstruction with quadriceps graft in short time follow-up in selected cases may have very satisfactory results. The method itself is simple, inexpensive, with small complication rate and with great patients satisfaction.
Bacteriophage therapy for bone and joint infections
Authors: Gibb Bryan P. , Hadjiargyrou Michael
Published: February 2021

Antibiotic resistance represents a threat to human health. It has been suggested that by 2050, antibiotic-resistant infections could cause ten million deaths each year. In orthopaedics, many patients undergoing surgery suffer from complications resulting from implant-associated infection. In these circumstances secondary surgery is usually required and chronic and/or relapsing disease may ensue. The development of effective treatments for antibiotic-resistant infections is needed. Recent evidence shows that bacteriophage (phages; viruses that infect bacteria) therapy may represent a viable and successful solution. In this review, a brief description of bone and joint infection and the nature of bacteriophages is presented, as well as a summary of our current knowledge on the use of bacteriophages in the treatment of bacterial infections. We present contemporary published in vitro and in vivo data as well as data from clinical trials, as they relate to bone and joint infections. We discuss the potential use of bacteriophage therapy in orthopaedic infections. This area of research is beginning to reveal successful results, but mostly in nonorthopaedic fields. We believe that bacteriophage therapy has potential therapeutic value for implant-associated infections in orthopaedics.

Cite this article: Bone Joint J 2021;103-B(2):234–244.
Developmental dysplasia of the hip screening programme in Chile
Authors: Sepúlveda Matías F. , Pérez Juan A. , Saban Esteban A. , Castañeda Luis E. , Sepúlveda Dalia F. , Birrer Estefanía A. M.
Published: February 2021

Purpose

Developmental dysplasia of the hip (DDH) encompasses a wide pathological spectrum, from mild acetabular dysplasia to complete congenital hip dislocation at birth. Screening policies have been implemented in an effort to effectively identify and treat patients with DDH. Since 2009 there has been a national DDH programme in Chile. The current study evaluates the results of the programme in patients born between 2010 and 2015.

Methods

Records of patients hospitalized from 1st January 2010 to 31st December 2019 were retrieved from national databases. Those born from 1st January 2010 to 31st December 2015 who underwent a procedure for DDH under general anaesthesia during their first five years of life were selected. Sex, first surgical procedure and age at first surgical procedure were analyzed. The incidence of DDH that required major surgical treatment was calculated.

Results

A total of 961 children born from 1st January 2010 to 31st December 2015 underwent a procedure for DDH during their first five years of life. The number of major procedures was significantly lower than the number of minor procedures (269 vs 692). The incidence of major procedures was 0.18 per 1000 live births. Girls underwent a higher number of procedures than boys (831 vs 130), whereas 39.2% of the boys and 26.2% of the girls had major procedures. The mean age at the time of the first procedure was 15.35 months (sd 10.09; range 0.03 to 55.92 months).

Conclusion

The present study suggests that the Chilean National DDH Screening Program is an appropriate programme with substantial benefits with respect to public health.

Level of evidence

II
The management of displaced femoral neck fractures: a narrative review
Authors: Sekeitto Allan Roy , Sikhauli Nkhodiseni , van der Jagt Dick Ronald , Mokete Lipalo , Pietrzak Jurek R.T.
Published: February 2021

This article serves to review the existing clinical guidelines, and highlight the most recent medical and surgical recommendations, for the management of displaced femoral neck fractures (FNFs). It stresses the need for multi-disciplinary intervention to potentially improve mortality rates, limit adverse events and prevent further economic liability. Globally, the incidence of FNFs continues to rise as the general population ages and becomes more active. The annual number of FNFs is expected to exceed six million by 2050. The increased burden of FNFs exacerbates the demand on all services associated with treating these injuries. The management of FNFs may serve as an indicator of the quality of care of the geriatric population. However, despite escalating health costs, a significant 30-day and one-year mortality rate, increased rate of peri-operative adverse events and sub-optimal functional clinical outcomes, continued controversy exists over optimal patient care. Much debate exists over the type of surgery, implant selection and peri-operative clinical care and rehabilitation. FNF care models, systematized clinical pathways, formal geriatrics consultation and specialized wards within an established interdisciplinary care framework may improve outcomes, mitigate adverse events and limit unnecessary costs.

Cite this article: EFORT Open Rev 2021;6:139-144. DOI: 10.1302/2058-5241.6.200036
Chronic exertional compartment syndrome of the forearm: a systematic review
Authors: Smeraglia Francesco , Tamborini Federico , Garutti Leonardo , Minini Andrea , Basso Morena A. , Cherubino Mario
Published: February 2021

The aim of this systematic review is to understand which surgical procedure provides better results in terms of pain relief and function in the treatment of chronic exertional compartment syndrome (CECS) of the forearm. We searched Medline (PubMed), Web of Science, Embase and Scopus databases on 8 July 2020. Twelve studies were included in this review. We assessed the quality of the studies using the Coleman Methodological Score. Data on demographic features, operative readings, diagnostic methods, follow-up periods, type and rates of complications, survivorship of the procedure, return to sport activity, and outcome measures were recorded. In conclusion, compared to the other techniques, endoscopic fasciotomy delivers similar success rates and lower incidence of complications.

Cite this article: EFORT Open Rev 2021;6:101-106. DOI: 10.1302/2058-5241.6.200107
Zentrum und Peripherie in der deutschen Syntax.
Authors: Näf Anton
Published: February 2021

The present paper is the first part of a larger essay which, due to space constraints, will be published in two separate parts. Using evidence of two small corpora, I develop a centre-periphery model inspired by the prototype theory and apply it to the syntax of German. In doing so I proceed in two steps. In the first part, published here, the graded four-level model of linguistic variation presented below (with the categories “prototype”, “variants”, “competitive forms” and “free stylistic variation”) is tested and refined on two already well-researched grammartical phenomena, namely conditionality and passive structures. In the second part (to be published in the next issue of Linguistik online) I apply the model to the more complex subject of sentence types in German, in particular the so-called minor sentence types. A complete description of a language should not only list the grammatical categories, but also contain quantitative information, on both the frequency of occurrence of a particular category and on the position and relative share of this category in the field of its competing means of linguistic expression. A grammar of contemporary German, which not only records the structures, but shows the “structures in use” in different domains and text types, still remains a desideratum.
Medical Image of the Month: Diffuse White Matter Microhemorrhages Secondary to SARS-CoV-2 (COVID-19) Infection
Authors:   University of Arizona, Tucson, AZ USA, Wickstrom Kelly , Blackstone Nicholas , Sam Afshin , El-Aini Tammer
Published: February 2021

No abstract available. Article truncated after 150 words. Clinical Scenario: A 59-year-old woman with hypothyroidism presented to the emergency room with progressive shortness of breath for 2 weeks. Upon arrival, she was markedly hypoxic necessitating use of a non-rebreather to maintain her oxygen saturations above 88%. A chest radiograph demonstrated extensive, bilateral airspace disease. She was diagnosed with SARS-CoV-2 (COVID-19) pneumonia and started on the appropriate therapies. Approximately 48 hours into her hospitalization, she required intubation with mechanical ventilation due to her progressive hypoxemic respiratory failure. She was intubated for approximately 5 weeks with a gradual improvement in her respiratory status, but not to the point where she was a candidate for a tracheostomy. Despite being off sedation for an extended period, she remained unresponsive. A CT of the head without contrast did not demonstrate any significant abnormalities. An MRI of the brain was subsequently performed and demonstrated diffuse juxtacortical and callosal white matter microhemorrhages (Figure 1). Given …
Modeling infrared behavior of multilayer diffractive optical elements using Fourier optics
Authors: Laborde Victor , Loicq Jérôme , Habraken Serge
Published: February 2021

In this paper, we propose to explore the infrared (IR) behavior of multilayer diffractive optical elements (MLDOEs). IR MLDOEs are designed for the development of space instruments dedicated to Earth observation. The phase effect of the MLDOE on a paraxial plane wave is studied using exact kinoform shapes for each layer. The modeling of the optical path difference uses thin element approximation. Until now, MLDOEs have been designed and simulated on ray-tracing software with binary diffractive layers. In this study, after passing through the MLDOE, the field is propagated using a method that utilizes the angular spectrum of plane waves. The Strehl ratio is used to determine the “best focus” plane, where it is shown that the focalization efficiency is above 95% for the working order in the mid- and long-wave IR bands. This result, along with the very low energy content of the other orders, proves the strong imaging potential of MLDOEs for dual-band applications. It is also demonstrated that the MLDOE has the same chromatic behavior as standard DOEs, making it a very useful component for IR achromatization.
Peculiarities of light pulse propagation in quasi-PT symmetric periodic structures
Authors: Shestakov P. Yu. , Komissarova M. V. , Marchenko V. F.
Published: February 2021

We study the peculiarities of light pulse propagation in the quasi-parity-time (quasi-

P

T

) symmetric periodic media in the Bragg geometry. Our focus is the investigation of the competition between the Bragg reflection and the

P

T

symmetry contribution provided different pulse duration. The mechanisms of nonsymmetric interaction between the counterpropagating waves are revealed and the various regimes of the monochromatic and nonmonochromatic wave propagation are determined. It is demonstrated that regardless the gain and loss level, the propagation of so-called long pulses in a quasi-

P

T

-symmetric medium is analogous to monochromatic waves propagation in a “pure”

P

T

-symmetric medium. At the same time, the transmittance of the short pulses is accompanied by strong distortions determined by the gain and loss level.
Analytical method for the diffraction of an electromagnetic wave by subwavelength graphene ribbons
Authors: Rahmanzadeh Mahdi , Khavasi Amin , Rejaei Behzad
Published: February 2021

Theoretical study of arrays of graphene ribbons is currently of high interest due to its potential application in beam splitters, absorbers, and polarizers. In this paper, an analytical method is presented for diffraction analysis of graphene ribbon arrays. Previous analytical studies were carried out in the regime where the lateral separation between the ribbons is much smaller than the wavelength of the incident wave. As such, they cannot be used to calculate the reflection coefficients of higher diffracted orders. In contrast, the method proposed here can predict the electromagnetic response of graphene ribbon arrays even when the array constant is larger than the wavelength. To reach our results, we first derive an analytical expression for the surface density of the electric current induced on the ribbons by an incident, transverse-magnetic, plane wave. Next, closed-form and analytical expressions are obtained for the reflection coefficients of the zeroth and higher diffracted orders. The results are in excellent agreement with those obtained from full-wave simulations. The method presented facilitates the design of tunable gratings with many potential applications in the terahertz regime and optics.
Design and analysis of a graphene-based Schottky junction solar cell with core/shell quantum dots as spectral downshifter
Authors: Haghighat Gholamhossein , Saghafi Kamyar
Published: February 2021

We theoretically design and study a structure of graphene/intrinsic amorphous-silicon Schottky junction solar cell (Gr/i-a-Si_SJSC) with top core/shell quantum dots (CSQDs). A physical model incorporated with optoelectrical characteristics is developed to optimize the structure’s electrical performance by modifying the graphene work function, temperature, and CSQD radius. Simulations show that the conversion efficiency of Gr/i-a-Si_SJSC is increased by increasing the graphene work function, raising the core radius and shell thickness of CSQD and decreasing the temperature. The results reveal that with an appropriate choice of design parameter in an optimized structure, short-circuit current density of

16.2

m
A

/

c
m

2

, open-circuit voltage of 0.8 V, fill factor of 75.06%, and calculated power conversion efficiency of 9.93% are obtained.
Poles, physical bounds, and optimal materials predicted with approximated Mie coefficients
Authors: Guidet Claire-Hélène , Stout Brian , Abdeddaim Redha , Bonod Nicolas
Published: February 2021

Resonant electromagnetic scattering with particles is a fundamental problem in electromagnetism that has been thoroughly investigated through the excitation of localized surface plasmon resonances (LSPR) in metallic particles or Mie resonances in high refractive index dielectrics. The interaction strength between electromagnetic waves and scatterers is limited by maximum and minimum physical bounds. Predicting the material composition of a scatterer that will maximize or minimize this interaction is an important objective, but its analytical treatment is challenged by the complexity of the functions appearing in the multipolar Mie theory. Here, we combine different kinds of expansions adapted to the different functions appearing in Mie scattering coefficients to derive simple and accurate expressions of the scattering electric and magnetic Mie coefficients in the form of rational functions. We demonstrate the accuracy of these expressions for metallic and dielectric homogeneous particles before deriving the analytical expressions of the complex eigen-frequencies (poles) for both cases. Approximate Mie coefficients can be used to derive simple but accurate expressions for determining complex dielectric permittivities that lead to poles of the dipolar Mie coefficient and ideal absorption conditions. The same expressions also predict the real dielectric permittivities that maximize (unitary limit) or minimize (anapole) electromagnetic scattering.