bluuebunny/crossref_metadata_2025 huggingface dataset:
Seeking Information: A Survey of Rural Spinal Patients’ Internet Use and Pain Catastrophizing
Authors: Thomas Kelly A. , Sedney Cara , Gross Richard
Published: April 2021

Objective Clinicians are beginning to evaluate the effects that Internet use has on patients. The aim of this study is to provide descriptive information on patients’ use of the Internet in regard to their spinal pain. Additionally, this study aims to examine the patient’s type of Internet usage (information vs. support) and its relationship to pain-related distress.

Materials and Methods This quantitative-descriptive, survey-based, correlational, cross-sectional design surveyed 143 spinal surgery patients from the Appalachian region. Participants were administered a demographic questionnaire, the pain catastrophizing scale, and an Internet Use and Spine Patients Questionnaire. Descriptive information on patient Internet use was collected through a retrospective recall of the participants’ Internet use and was analyzed utilizing a frequency distribution. A Pearson (r) correlation was conducted to determine the relationship between Internet use and the severity of pain catastrophizing.

Results Spinal surgery patients more frequently use the Internet for information than for support. For the individuals who do utilize the Internet for information, most are finding this tool to be somewhat helpful. For spinal patients who do use the Internet for support, there was a positively correlated relationship with magnification, helplessness, and overall pain catastrophizing.

Conclusion Patients who present for spinal surgery are generally using the Internet to gain information on their diagnoses. Pain catastrophizing was elevated in relation to Internet use for support. Limitations and future directions are discussed.
Anxiety in Parkinson’s Disease: Correlation with Depression and Quality of Life
Authors: Upneja Ankush , Paul Birinder S. , Jain Dinesh , Choudhary Rupesh , Paul Gunchan
Published: April 2021

Introduction Anxiety is common in patients with Parkinson’s disease (PD). Its prevalence ranges from 20 to 40% but despite that, the high prevalence anxiety in PD is often undiagnosed and untreated. This research was aimed to study the pattern of anxiety with regard to its prevalence and risk factors and to establish the association of anxiety with depression and quality of life (QOL) in patients with PD.

Methods A total of 105 patients with PD were prospectively observed. Demographic and clinical variables were recorded and patients were assessed for anxiety (the Parkinson anxiety scale [PAS]), depression (geriatric depression scale [GDS]), and QOL (Parkinson’s Disease Questionnaire-39 [PDQ-39]). Multiple forward logistic regression analysis was done for parameters showing association with anxiety. Pearson’s correlation was used to calculate the strength of association of depression and QOL with anxiety.

Results Anxiety was present in 56 PD patients (53.3%). Episodic anxiety was noted in 50%, avoidance behavior in 35%, and persistent anxiety in 15% of these patients. There was significant association of anxiety with duration of disease (p = 0.001), severity (p < 0.005), levodopa equivalent dose (LED; p = 0.001), and tremor phenotype of PD (p = 0.004). Anxiety coexisted with depression in 50 patients (79.4%), which was statistically significant in our cohort (p = 0.001). There was significant linear relationship between the PAS and PDQ-39.

Conclusion Anxiety exerts a negative impact on the QOL as revealed by proportionately worsening PDQ-39 and PAS scores. Screening for anxiety will allow efficient delivery of support and treatment to patients with PD and their families.
Hydrocephalic Dementia: Revisited with Multimodality Imaging and toward a Unified Imaging Approach
Authors: Mangalore Sandhya , Vankayalapati Sriharish , Gupta Arun Kumar
Published: April 2021

Objective Overlap of normal pressure hydrocephalus (NPH) and pathology proven cases of dementia is known. The objective of this paper is to correlate both the clinical and multimodality imaging findings in patients with imaging diagnosis NPH and give a hypothesis for association of clinical findings.

Methods This is a retrospective observational analysis of 13 cases patients who were referred to molecular imaging center for imaging in 2016 to 2019, and they were divided into four groups based on structural imaging findings. Group 1 had magnetic resonance imaging (MRI) findings of diffuse effacement of sulcal spaces (DESH) and flow void, whereas Group 4 had none of these two. Group 3 had MRI findings of DESH but no flow void, and Group 2 had flow void but no DESH. Clinical presentation, MRI-PET findings of four groups are assessed.

Results Groups with presence of flow void showed hypometabolism in the medial frontal and medial temporal lobe. Groups with presence of DESH has effacement of parietal sulci showed parietal hypo metabolism with clinical presentation AD/mixed dementia and absence of parietal effacement showed FTD-like presentation. Groups without flow void or DESH showed only mild medial temporal hypometabolism and presented with classical signs of NPH. ASL perfusion changes are in correlation with metabolism on positron emission tomography (PET)-MRI.

Conclusion This study has led us to hypothesize the lack of outflow of brain protein and their deposition in parenchyma based on pressure gradient would be easier explanation to go with cluster of findings. MR-PET and other investigations each had different specificity and sensitivity and different pattern of presentation.
Pseudocyesis Leading to Folie-à-Deux
Authors: Nagdive Amit B. , Bhainsora Ravi Singh , Fernandes Rouchelle , Behere Prakash B. , Sethi Siddharth
Published: April 2021

Pseudocyesis or false belief of pregnancy is the emergence of classical manifestations of pregnancy—nausea, breast enlargement and pigmentation, abdominal distention, amenorrhea, and labor pains—in a nonpregnant woman. It is a multifactorial disease and its development is influenced by many different elements such as neuroendocrine, social, psychodynamic, and cultural issues. “Folie-à-deux,” is shared psychotic disorder, describes a syndrome in which delusion is transferred to another person who is more susceptible. Both individuals are closely related or know each other for a long time and typically live together in relative social isolation. In its commonest form, the individual who first develops the delusion (the primary case) is often chronically ill and typically is the dominant member in a close relationship with a more suggestible person (the secondary case) who also develops the delusion. Treatment options should also be kept in mind as antipsychotics themselves can increase prolactin levels and can lead to amenorrhoea and galactorrhea and can further strengthen patient’s belief about her pregnancy. This case highlights that the most important therapeutic step in the treatment of folie-à-deux is separation of the inducer and the induced. Here we describe a case of folie-à-deux of a married couple in which the female had delusional pregnancy while the husband shared and supported her delusion against substantial medical evidence.
Increased VWF and Decreased ADAMTS-13 in COVID-19: Creating a Milieu for (Micro)Thrombosis
Authors: Favaloro Emmanuel J. , Henry Brandon Michael , Lippi Giuseppe
Published: April 2021

von Willebrand factor (VWF) is a large adhesive multimeric protein involved in hemostasis. The larger the size (or number of VWF multimers), the greater the functionality of the protein. A deficiency or defect of VWF can lead to von Willebrand disease (VWD) and cause bleeding. Conversely, an increase in VWF may create an environment that promotes thrombosis. ADAMS-13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13), sometimes called VWF-cleaving protease, is primarily responsible for controlling the size of VWF. The most severe deficiency (<10% of normal levels) of ADAMTS-13 arises in thrombotic thrombocytopenic purpura, a condition characterized by the presence of ultralarge VWF and clinically resulting in enhanced risk of thrombosis. However, ADAMTS-13 deficiency may result from other pathological processes. Of relevance is the recent finding that COVID-19 (coronavirus disease 2019) is associated with both increased levels and activity of VWF as well as generally decreased (or occasionally normal) activity levels of ADAMTS-13. Thus, in COVID-19 there is an alteration in the VWF/ADAMTS-13 axis, most often described by increased VWF/ADAMTS-13 ratio (or reduced ADAMTS-13/VWF ratio). COVID-19 is also associated with high prothrombotic risk. Thus, the imbalance of VWF and ADAMTS-13 in COVID-19 may be providing a milieu that promotes (micro)thrombosis, in a clinical picture resembling a secondary thrombotic microangiopathy in some patients. This review therefore assesses the literature on VWF, ADAMTS-13, and COVID-19. Whenever reported in COVID-19, VWF has always been identified as raised (compared with normal reference ranges or control populations). Reports have included VWF level (i.e., VWF antigen) and in some cases one or more VWF “activity” (e.g., collagen binding; platelet glycoprotein Ib [GPIb] binding, using ristocetin cofactor or more modern versions including VWF:GPIbR [recombinant] and VWF:GPIbM [mutant]). Whenever reported, ADAMTS-13 has been reported as “normal” or reduced; however, it should be recognized that “normal” levels may still identify a relative reduction in individual cases. Some reports also discuss the raised VWF/ADAMTS-13 (or reduced ADAMTS-13/VWF) ratio, but very few provide actual numerical data.
Venous Thromboembolism in Patients Discharged after COVID-19 Hospitalization
Authors: Engelen Matthias M. , Vandenbriele Christophe , Balthazar Tim , Claeys Eveline , Gunst Jan , Guler Ipek , Jacquemin Marc , Janssens Stefan , Lorent Natalie , Liesenborghs Laurens , Peerlinck Kathelijne , Pieters Griet , Rex Steffen , Sinonquel Pieter , Van der Linden Lorenz , Van Laer Christine , Vos Robin , Wauters Joost , Wilmer Alexander , Verhamme Peter , Vanassche Thomas
Published: April 2021

Background Venous thromboembolism (VTE) is a frequent complication of COVID-19, so that the importance of adequate in-hospital thromboprophylaxis in patients hospitalized with COVID-19 is well established. However, the incidence of VTE after discharge and whether postdischarge thromboprophylaxis is beneficial and safe are unclear. In this prospective observational single-center study, we report the incidence of VTE 6 weeks after hospitalization and the use of postdischarge thromboprophylaxis.

Methods Patients hospitalized with confirmed COVID-19 were invited to a multidisciplinary follow-up clinic 6 weeks after discharge. D-dimer and C-reactive protein were measured, and all patients were screened for deep vein thrombosis with venous duplex-ultrasound. Additionally, selected high-risk patients received computed tomography pulmonary angiogram or ventilation–perfusion (V/Q) scan to screen for incidental pulmonary embolism.

Results Of 485 consecutive patients hospitalized from March through June 2020, 146 patients were analyzed, of which 39% had been admitted to the intensive care unit (ICU). Postdischarge thromboprophylaxis was prescribed in 28% of patients, but was used more frequently after ICU stay (61%) and in patients with higher maximal D-dimer and C-reactive protein levels during hospitalization. Six weeks after discharge, elevated D-dimer values were present in 32% of ward and 42% of ICU patients. Only one asymptomatic deep vein thrombosis (0.7%) and one symptomatic pulmonary embolism (0.7%) were diagnosed with systematic screening. No bleedings were reported.

Conclusion In patients who had been hospitalized with COVID-19, systematic screening for VTE 6 weeks after discharge revealed a low incidence of VTE. A strategy of selectively providing postdischarge thromboprophylaxis in high-risk patients seems safe and potentially effective.
Prostate-Specific Antigen: From Promising to Disappointment Tool for Diagnosis of Chronic Renal Failure in Predialysis Patients
Authors: Al-Janabi Ali Abdul Hussein S
Published: April 2021

Introduction Prostate-specific antigen (PSA) is a biomarker commonly used for detection of prostate cancer. Its viability as a marker for diagnosis of chronic renal failure (CRF) in predialysis patients was investigated.

Methods Sera from 230 patients with CRF were analyzed by enzyme-linked immunosorbent assay (ELISA) for determining total PSA (tPSA) levels before hemodialysis.

Results Of the patients investigated, 98.69% had a normal PSA level with a value less than 4 ng/mL. Three elderly men with both kidney failure showed a moderate elevation of PSA level.

Conclusion PSA is considered a nonsignificant indicator for diagnosis of CRF.
Bark charcoal reflectance may have the potential to estimate the heat delivered to tree boles by wildland fires
Authors: Belcher Claire M. , New Stacey L. , Gallagher Michael R. , Grosvenor Mark J. , Clark Kenneth , Skowronski Nicholas S.
Published: April 2021

Currently, our ability to link wildland fire behaviour to fire effects is through the lens of fire severity assessments, because there are no ground-based post-fire metrics that are able to quantitively capture aspects of heat transfer to plants. This presents a particular challenge when considering tree mortality linked to cambial damage, which can occur in both low-intensity surface fires through to high-intensity crown fires. Recent research suggests that measuring the amount of light reflected from charcoals produced by wildland fires will provide information about the energy flux that created the char. We created an experimental forest fire in which we had instrumented individual trees to record the energy delivered to the bark close to the base of the trees. We then assessed the bark charcoal reflectance of the same trees. We found that bark charcoal reflectance showed a strong positive correlation (r2 > 0.86, P = 0.0031) with increasing duration of heating and the total energy delivered to the bark. We suggest that this may provide useful quantitative data that can be included in models or post-fire surveys to estimate tree mortality due to cambial kill.
Planning for sustainable tourism development in Bhutan.
Authors: Pratt Stephen , Suntikul Wantanee
Published: April 2021

This chapter investigates the ways in which tourism planning and policies in Bhutan promote, reinforce and constrain sustainability. The scope of this work covers food and beverage purchasing decisions, human resources, transportation and souvenir sales in the tourism and hospitality industry in Bhutan. To achieve these research objectives, 19 in-depth interviews were conducted with hotel general managers in the main tourism areas of Thimphu and Paro. The findings reveal that, while the controlled nature of tourism in Bhutan certainly protects its residents from the negative excesses of global tourism, numerous policies also impede tourism and hospitality from spreading their benefits more widely. Policy makers in Bhutan would rather adhere to the precautionary principle than allow detrimental practices or risk irreversible impact on Bhutanese culture.
Tourism policy planning in Bangladesh: perspective and propositions.
Authors: Hassan Azizul
Published: April 2021

This chapter critically discusses tourism policy planning from a comprehensive viewpoint in the Bangladesh context by presenting research having a particular focus on tourism policy planning, instruments, organizational involvement and implementation. Incorporating the respondent views, this research also generates some specific suggestions for tourism policy planning in Bangladesh.
Tourism development and its impact on economic growth in Pakistan.
Authors: Fauzel Sheereen , Jaffur Zameelah Khan , Seetanah Boopen
Published: April 2021

This chapter discusses in the first instance the development of tourism in Pakistan, delving into the government's support of it and its potential as well as the challenges of the industry. The chapter subsequently investigates the impact of tourism development on economic growth in Pakistan over the period 1980 to 2018 using a dynamic time-series analysis, namely a vector autoregressive framework, which allows for the possibility of endogeneity and causality issues. The results proved the existence of the tourism-led growth hypothesis and that tourism development has contributed to economic growth in the long run; perhaps not as much as it could have given the potential of this sector. A bidirectional causality is also reported between tourism development and economic growth, confirming the self-reinforcing nature of the tourism-growth nexus.
The role of international tourism in the Maldives.
Authors: Sathiendrakumar Rajasundram , Jaffur Zameelah Khan , Seetanah Boopen
Published: April 2021

This chapter considers the development of tourism in the Maldives and delves into tourism planning and promotion since the 1970s. It also empirically investigates the impact of tourism on economic growth in the Maldives from 1995 to 2016 in both static and dynamic time-series analysis settings. Both the static and dynamic regression results depicted a positive and quite sizeable relationship between tourism and economic growth. It is noteworthy that the analysis could not confirm any relationship in the short run, suggesting that tourism development has its full effect on the economy with time.
Bactrocera dorsalis (oriental fruit fly).
Authors: Leblanc Luc
Published: April 2021

Bactrocera dorsalis is a highly invasive species. Native to Asia, Oriental fruit fly is now found in at least 65 countries, including parts of America and Oceania, and most of continental Africa (sub-Saharan countries). The potential risk of its introduction to a new area is facilitated by increasing international tourism and trade, and is influenced by changes in climate and land use. After introduction, it can easily disperse as it has a high reproductive potential, high biotic potential (short life cycle, up to 10 generations of offspring per year depending on temperature), a rapid dispersal ability and a broad host range. The economic impact would result primarily from the loss of the export markets and the costly requirement of quarantine restrictions and eradication measures. Furthermore, its establishment would have a serious impact on the environment, following the initiation of chemical and/or biological control programmes. Invasive B. dorsalis has been shown to be highly competitive with native fruit flies where it has established, quickly becoming the dominant fruit fly pest (Duyck et al., 2004; Vargas et al., 2007; Vayssières et al., 2015). Oriental fruit fly is of quarantine significance to EPPO (European Plant Protection Organization), APPPC (Asia and Pacific Plant Protection Commission), COSAV (Comité de Sanidad Vegetal del Cono Sur), CPPC (Caribbean Plant Protection Commission), IAPSC (Inter-African Phytosanitary Council) and OIRSA (Organismo Internacional Regional de Sanidad Agropecuaria) countries.
The hits and misses of Namibia’s attempt to implement the Ecosystem Approach to Fisheries (EAF) Management
Authors: Iitembu Johannes A. , Erasmus Victoria N. , Uanivi Uatjavi , Nakwaya Dietlinde , Horaeb Richard R. , Nangolo Ester , Nashima Festus P. , Iita Theopolina K. , Mwandemele Osmund
Published: April 2021

Ecosystem Approach to Fisheries (EAF) management is a concept aimed at the conservation and sustainable use of the entire ecosystem. While EAF is a noble approach, its implementation has been challenging. Although Namibia has committed to the implementation of EAF, only limited assessment has been done of Namibian fisheries management processes and instruments concerning EAF. A qualitative assesment was done to ascertain if the Namibian fisheries management processes and instruments conform to the EAF principles. Namibian fisheries management processes and instruments largely conform to the EAF principles, although there are notable areas needing improvements. The conformities were pronounced in the total allowable catch setting, rebuilding depleted stocks, minimizing bycatch, and fishing impact minimization. The polluter pays, and user pays principles were also applied. Areas that were found lacking in this study included setting the indicators for EAF and ecosystem integrity. The assessment also noted the absence of guidelines for the precautionary approach principle and a transparent policy for quota and right allocation processes. The strategies for managing transboundary fish species are also not formulated. Overall, this assessment showed the complexities and challenges that Namibia and other countries need to overcome to implement EAF successfully.
Chronic interleukin-1 exposure triggers selection for Cebpa-knockout multipotent hematopoietic progenitors
Authors: Higa Kelly C. , Goodspeed Andrew , Chavez James S. , De Dominici Marco , Danis Etienne , Zaberezhnyy Vadym , Rabe Jennifer L. , Tenen Daniel G. , Pietras Eric M. , DeGregori James
Published: April 2021

The early events that drive myeloid oncogenesis are not well understood. Most studies focus on the cell-intrinsic genetic changes and how they impact cell fate decisions. We consider how chronic exposure to the proinflammatory cytokine, interleukin-1β (IL-1β), impacts Cebpa-knockout hematopoietic stem and progenitor cells (HSPCs) in competitive settings. Surprisingly, we found that Cebpa loss did not confer a hematopoietic cell–intrinsic competitive advantage; rather chronic IL-1β exposure engendered potent selection for Cebpa loss. Chronic IL-1β augments myeloid lineage output by activating differentiation and repressing stem cell gene expression programs in a Cebpa-dependent manner. As a result, Cebpa-knockout HSPCs are resistant to the prodifferentiative effects of chronic IL-1β, and competitively expand. We further show that ectopic CEBPA expression reduces the fitness of established human acute myeloid leukemias, coinciding with increased differentiation. These findings have important implications for the earliest events that drive hematologic disorders, suggesting that chronic inflammation could be an important driver of leukemogenesis and a potential target for intervention.
Final report of the new BIPM comparison BIPM.RI(II)-K1.Tb-161 of activity measurements of the radionuclide 161Tb including the 2019 result of the IRA (Switzerland)
Authors: Michotte C , Courte S , Nonis M , Coulon R , Judge S , Juget F , Nedjadi Y , Durán M T
Published: April 2021

Main text

In 2019, the IRA (Switzerland) submitted a sample of 161Tb to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)- K1.Tb-161. As IRA is the first participant in the comparison no key comparison reference value (KCRV) and no degrees of equivalence can be calculated.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.

The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
CCQM-K146.1 subsequent comparison low-polarity analyte in high fat food: benzo[a]pyrene in olive oil
Authors: Li Xiaomin , Li Hongmei , Zhang Qinghe , Lu Xiaohua , Kakoulides Elias , Quinn L , Fernandes-Whaley M , Bucar-Miklavcic Milena , Bester Erika , Butinar Bojan , Gokcen Taner , Bilsel Mine
Published: April 2021

Main text

The Track A key comparison on the determination of benzo[a]pyrene in olive oil (CCQM-K146) organized by the CCQM was finished in 2020. This key comparison was related to low polarity analytes in a high fat, low protein, low carbohydrate food matrix and was the model system selected to align with the OAWG strategy for comparisons to underpin the food sector. Due to requests from the participants of this comparison, CCQM organized a supplementary comparison CCQM-K146.1 for those NMIs or DIs who did not participate in CCQM-K146 or wished to improve their results from CCQM-K146.

5 NMIs and DIs participated in CCQM-K146.1. Different extraction methods and SPE cartridges were applied in the sample pre-treatment. HPLC-FLD, GC-MS/MS and GC-TOF MS were applied for detection by the participants. Certified reference materials (CRMs) were adopted or pure materials assessed in house to guarantee traceability to SI for the calibrants.

NIM's result for CCQM-K146 was equivalent with the CCQM-K146 KCRV, thus they demonstrated acceptable performance in determining the measurand and their result for CCQM-K146.1 was used as the KCRV. The KCRV and u(KCRV) values were 8.69 μg/kg and 0.18 μg/kg, respectively. The random effects model obtained in CCQM-K146 suggests a dark uncertainty term (tau) is present, and the tau of CCQM-K146 normalized to CCQM-K146.1 measurand level is included in the estimation of degrees of equivalence (DoE) for the participants in CCQM-K146.1. This helps establish a consistent expectation of performance amongst the two studies, even when comparing to a different anchor KCRV.

One participant demonstrated their capabilities for this analysis, whereas the other three were all deviated from the KCRV. This supplementary comparison directly illustrates the capabilities in determining mass fraction of organic compounds, with molecular mass of 100 g/mol to 500 g/mol, having low polarity pKow < -2, in mass fraction range from 0.1 μg/kg to 1000 μg/kg in a high fat, low protein, low carbohydrate food matrix.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.

The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
A new interpretation of (Tikhonov) regularization
Authors: Gerth Daniel
Published: April 2021

Tikhonov regularization with square-norm penalty for linear forward operators has been studied extensively in the literature. However, the results on convergence theory are based on technical proofs and sometimes difficult to interpret. It is also often not clear how those results translate into the discrete, numerical setting. In this paper we present a new strategy to study the properties of a regularization method on the example of Tikhonov regularization. The technique is based on the well-known observation that Tikhonov regularization approximates the unknown exact solution in the range of the adjoint of the forward operator. This is closely related to the concept of approximate source conditions, which we generalize to describe not only the approximation of the unknown solution, but also noise-free and noisy data; all from the same source space. Combining these three approximation results we derive the well-known convergence results in a concise way and improve the understanding by tightening the relation between concepts such as convergence rates, parameter choice, and saturation. The new technique is not limited to Tikhonov regularization, it can be applied also to iterative regularization, which we demonstrate by relating Tikhonov regularization and Landweber iteration. All results are accompanied by numerical examples.
The quantum scattering time in a linear potential
Authors: Xiao Zhi , Zheng Shuang , Liu Ji-Cai
Published: April 2021

In this paper, we calculate the quantum time delays for a neutral particle scattering off the Earth gravitational linear potential. The quantum time delays are obtained by subtracting the classical returning time (CRT) from the Wigner time, the dwell time and the Larmor time respectively. Different from the conventional definition, our Larmor time is defined by aligning the magnetic field along particle’s direction of motion, and this definition does give reasonable results for motions through a free region and a square barrier. It is worth noting that in the zero magnetic field limit, the Larmor time coincides well with the CRT, which is due to the special shape of linear barrier, and may have some relevance to the weak equivalence principle. It is also found that the classical forbidden region plays an essential role for the dwell time

τ

DW

to match with the CRT, and the difference between the dwell and the phase times, i.e. the self-interference time delay, is barrier shape sensitive and clearly shows the peculiarity of the linear barrier. All the time delays are on the order of sub-millisecond and exhibit oscillating behaviors, signaling the self-interference of the scattering particle, and the oscillations become evident only when the de Broglie wavelength λ

k
= 2π/k is comparable to the characteristic length

L

c

=

[

2

m

2

g
/

ℏ

2

]

−
1
/
3

. If the time delay measurement is experimentally realizable, it can probe the quantum nature for particle scattering off the gravitational potential in the temporal domain.
Measurement of the free electron line density in a spherical theta-pinch plasma target by single wavelength interferometry
Authors: Christ P , Cistakov K , Iberler M , Laghchioua L , Mann D , Rosmej O , Savin S , Jacoby J
Published: April 2021

A single wavelength heterodyne interferometer has been set up to investigate the free electron density integrated axially along the line of sight (line density) in a theta-pinch plasma to determine its applicability as a plasma target for ion beam stripping. The maximal line density reached in this experiment was

3

.

57
±
0

.

28

×

10

18

cm−2 at 80 Pa and 20 kV. The findings demonstrate the pulsed character of the line density and its increase by raising the load voltage and the working gas pressure. Additionally, the results were compared with spectroscopic free electron density estimations, which were carried out by H

β

-line broadening and peak separation. The time behavior of the line density indicates that its peak value is delayed by about 10 µs compared to the spectroscopic results. This effect is due to the formation of an extended, magnetically compressed plasma column in the vicinity of the current maximum, although the highest volumetric free electron density is reached near the current zero crossing. Since the line density is an essential parameter in describing the stripping capabilities of the plasma target, the interferometric diagnostic is superior to a spectroscopic diagnostic, because it directly provides integrated values along the line of sight. Furthermore, the measurements of the line density in this experiment partially show nonphysical negative values, which is due to gaseous effects and residual shot vibrations.
Experimental observation of the linear gain of back-illuminated ultraviolet avalanche photodiodes using a GaN/AlN periodically stacked structure
Authors: Kang Jianbin , Li Qian , Wan Yongbiao
Published: April 2021

Semiconductor-based avalanche photodiodes (APDs) have the advantages of lower power and simpler fabrication of arrays compared with photomultiplier tubes. It is critical for weak-light imaging that the APD is operated under back illumination and with high linear gain. However, linear gain is fairly low for conventional PIN APDs. This paper presents a back-illuminated APD, whose multiplication layer is designed to be a GaN/AlN periodically stacked structure. The GaN/AlN heterostructure is introduced to enhance the ratio of ionization coefficient between electrons and holes, which proves to be helpful for increasing the linear gain. Under back illumination, the prototype device demonstrates a record-high external quantum efficiency (reflecting linear gain) of ∼5 × 102 at the reverse bias of 66 V. The device response spectra were also studied to further confirm that only the photo-excited electrons can trigger the collision ionization in the multiplication layer.
Effects of 10 MeV Al4+ ions irradiation on fluorine-doped tin oxide substrates for photovoltaic device applications
Authors: Pandey Anand , Patel M S , Chaudhary Dhirendra K , Patel Shiv P , Pali L Sowjanya , Garg Ashish , Kumar Lokendra
Published: April 2021

The effects of 10 MeV Al4+ ions irradiation on structural, surface morphological, optical and electrical properties of fluorine-doped tin oxide (FTO) substrates are presented for solar cell applications. The ions irradiation changes the surface morphology, average roughness, interface width, roughness exponent, and several other fractal parameters of the FTO surfaces. The UV–visible transmittance measurement shows an enhancement of transmittance in the ions irradiated substrates up to 95%. The electrical properties such as mobility, work-function, sheet resistance, and resistivity are also modified due to ions irradiation. In order to have functional applications of these ions irradiated substrates, we fabricated organic solar cells on these ions irradiated and pristine FTO substrates. The device performances are significantly improved for the case of ions irradiated FTO substrate in comparison to the pristine one. Thus, better device performance due to effective changes in physical properties suggests that the ions irradiated FTO substrates can be used as better electrodes for organic and hybrid photovoltaic device applications.
Semiconductor heterojunction photocatalysts with near-infrared light antennas: a review
Authors: Lu Yue , Wang Yuyan , Zhang Junying
Published: April 2021

Photocatalysts are expected to contribute to the sustainable development of human society due to their ability of converting solar energy to chemical fuel and removing environmental contamination. In principle, photocatalytic efficiency is intimately related to the availability of sunlight, and thus it is vital to extend the light absorption range to the low-energy near-infrared (NIR) region. A great deal of effort has been devoted to exploring NIR-driven photocatalysts and consequently various light antennas have been reported, which can be coupled with wide bandgap semiconductors to form heterojunctions. In this review, recent progress in NIR-driven heterojunction photocatalysts is summarized, introducing in detail the variety and functionality of four types of light antennas including dyes, up-conversion carbon-based quantum dots, plasmonic materials and narrow bandgap semiconductors. This review emphasizes the effects of the heterojunction structure on the photocatalytic properties and summarizes the representative research results of NIR light antennas, aiming to promote the exploration of novel NIR light harvesting materials.
Vector magneto-optical magnetometer based on resonant all-dielectric gratings with highly anisotropic iron garnet films
Authors: Ignatyeva Daria O , Knyazev Grigory A , Kalish Andrey N , Chernov Alexander I , Belotelov Vladimir I
Published: April 2021

Sensitive vector magnetometry with high spatial resolution is important for various practical applications, such as magnetocardiography, magnetoencephalography, explosive materials detection and many others. We propose a magnetometer based on magnetic iron garnet film possessing a very high magnetic anisotropy, placed in a rotating external magnetic field. Each of the measured magnetic field spatial components produces different temporal harmonics in the out-of-plane magnetization dependence. Our analysis based on numerical simulation shows that the dielectric resonant grating placed on the top of an ultrathin film enhanced the magneto-optical (MO) response by ten times. It allows one to reduce the thickness of the film, which makes it possible to achieve several times higher spatial resolution in the perpendicular to the film direction, up to 30 nm. The reported MO magnetometer allows one to measure simultaneously all three spatial components of the magnetic field with high spatial resolution and sensitivity up to 100 pT Hz-1/2.
Effect of the uncertainty in the hadronic interaction models on the estimation of the sensitivity of the Cherenkov telescope array
Authors: Ohishi Michiko , Arbeletche Luan , de Souza Vitor , Maier Gernot , Bernlöhr Konrad , Olaizola Abelardo Moralejo , Bregeon Johan , Arrabito Luisa , Yoshikoshi Takanori
Published: April 2021

Imaging atmospheric Cherenkov telescopes (IACTs) are ground-based indirect detectors for cosmic gamma rays with energies above tens of GeV. The major backgrounds for gamma-ray observations in IACTs are cosmic-ray charged particles. The capability to reject these backgrounds is the most important factor determining the gamma-ray sensitivity of IACT systems. Monte Carlo simulations are used to estimate the residual background rates and sensitivity of the systems during the design and construction phase. Uncertainties in the modeling of high-energy hadronic interactions of cosmic rays with nuclei in the air propagate into the estimates of residual background rates and subsequently into the estimated instrument sensitivity. We investigate the influence of the difference in the current hadronic interaction models on the estimated gamma-ray sensitivity of the Cherenkov Telescope Array using four interaction models (QGSJET-II-03, QGSJET-II-04, EPOS-LHC, and SIBYLL2.3c) implemented in the air shower simulation tool CORSIKA. Variations in background rates of up to a factor 2 with respect to QGSJET-II-03 are observed between the models, mainly due to differences in the π
0 production spectrum. These lead to ∼30% differences in the estimated gamma-ray sensitivity in the 1–30 TeV region, assuming a 50 h observation of a gamma-ray point-like source. The presented results also show that IACTs have a significant capability in the verification of hadronic interaction models.
Spin correlations and spin-density wave phase in a finite-temperature quasi-one-dimensional electron gas
Authors: Kaur Kulveer , Sharma Akariti , Garg Vinayak , Moudgil R K
Published: April 2021

In this paper, we theoretically investigate the effect of temperature on spin correlations in an unpolarized quasi-one-dimensional electron gas (Q1DEG). The correlations are treated dynamically within quantum version of the self-consistent mean-field approach of Singwi et al Numerical results for the ↑↑ and ↑↓ components of static structure factor and pair-correlation function, and the wave vector dependent static spin and charge susceptibilities are presented over a wide range of temperature T and electron coupling r

s
. We find that the recently reported (2020 J. Phys.: Condens. Matter.
32 335403) non-monotonic T-dependence of the contact pair-correlation function g(r = 0; T) is driven primarily by an interplay between ↑↓ correlations and thermal effects. At a given temperature, the dynamics of both ↑↑ and ↑↓ correlations is found to become significant with increasing coupling r

s
, manifesting unambiguously as pronounced peak at 3.5k
F (periodic oscillations) in the corresponding components of the structure factor (pair-correlation function). Analysis of static spin and charge susceptibilities reveals that an imbalance between ↑↑ and ↑↓ correlations may induce a transition to a spin-density wave (SDW) phase of wave vector ∼3.5k
F above a critical coupling for a sufficiently high T, while to a long-wavelength SDW phase at a low T. Higher the temperature, higher is the predicted critical coupling for the SDW phase. Interestingly, transition to the SDW phase is found to precede the recently predicted Wigner crystal instability in the finite-T Q1DEG. Further, if one starts with partially spin-polarized electrons, the SDW instability is found to shift to somewhat higher τ and r

s
. In addition, we have presented results for the free exchange-correlation energy, free correlation energy, and excess kinetic energy for the unpolarized and fully spin-polarized phases of the finite-T Q1DEG. Wherever interesting, we have compared our results with the predictions of the static version of the mean-field approach.
Personal dosimeter utilisation among South African interventionalists
Authors: Rose André , Uebel Kerry , Rae William Ian Duncombe
Published: April 2021

Ionising radiation (IR) is increasingly being used in diagnostic and therapeutic procedures and offers increased benefits to patients but poses an increased occupational health risk to operators. The consistent use and monitoring of radiation health care workers’ dosimeters is an important part of the process for ensuring adequate monitoring and control of IR in the workplace. There is however often inconsistent dosimeter utilisation among these workers. The aim of this study was to report on the dosimeter utilisation and dosimetry practices in South African interventionalists. We conducted a survey and did in-depth and group interviews to evaluate dosimetry practices and the factors influencing these practices. We used STATA 15 to do a descriptive analysis of the quantitative data. A thematic analysis of the qualitative data was done using a deductive and inductive approach. There were 108 respondents (35 radiologists, 41 adult cardiologists, 32 paediatric cardiologists). The majority overall (65.8%), and in each category were males. The median age was 44 (interquartile range (IQR) 31–66)) and the median years worked with fluoroscopy was 10 years (IQR 1–32). Overall interventionalists (55%) ranked their perceived occupation risk as 2/10. Thirteen per cent of all interventionalists reported never using a personal dosimeter (PD), 58% reported wearing it >70% of the time. Inconsistent and inappropriate use of PDs emerged strongly from the qualitative data. There was poor dosimeter utilisation in this study. Participants were not aware of the role of medical physics departments. Evaluation of dosimetry practices as a means of monitoring and improving radiation safety in the catheterisation laboratory must be improved to create an improved culture of radiation safety and protection.
In situ tailoring the morphology of In(OH)3 nanostructures via surfactants during anodization and their transformation into In2O3 nanoparticles
Authors: Ali Tariq , Mohyuddin Saima , Ali Ghafar , Khan Maaz , Iqbal Sajid , Maqbool Muhammad , Cho Sung Oh
Published: April 2021

The present work reports the effect of various surfactants on the morphology of In(OH)3 nanostructures prepared via anodization. In-sheets were anodized in an environmentally benign electrolyte containing a small quantity of CTAB, CTAC, and PDDA surfactants at room temperature. The produced nanostructures were characterized using XRD, HRTEM, SAED, and EDAX. The morphology of indium hydroxide (In(OH)3) nanostructures was successfully tailored in situ with the help of surfactants in 1 M KCl aqueous electrolyte. XRD results confirmed the formation of In(OH)3 and indium oxyhydroxide (InOOH) nanostructures in the pristine form which were transformed into single-phase cubic In2O3 nanoparticles (NPs) after calcination. HRTEM analyses showed that the morphology and size of the In(OH)3 nanostructures can be tuned to form nanorods, nanosheets and nanostrips using different surfactants. The results revealed that CTAC and PDDA surfactants have a profound effect on the morphology of In(OH)3 nanostructure compared to CTAB due to the higher concentration of Cl− ion. The possible mechanism of surfactants effect on the morphology is proposed. Furthermore, annealing converted the In(OH)3 nanostructures into spherical In2O3 NPs with uniform and homogeneous size. We anticipate that the morphology of other metal-oxides nanostructure can be tuned using this simple, facile and rapid technique. In2O3 NPs prepared without and with CTAB surfactant were further explored for the non-enzymatic detection of hydrogen peroxide (H2O2). Electrochemical measurements showed enhanced electrocatalytic performance with fast electron transfer (∼2s) between the redox centers of H2O2 and electrode surface. The In2O3 NPs prepared using CTAB/Au electrode exhibited about 4-fold increase in sensitivity compared to the bare Au electrode. The biosensor also demonstrated good reproducibility, higher selectivity, and increased shelf life.
Size effect of hybrid carbon nanofillers on the synergetic enhancement of the properties of HDPE-based nanocomposites
Authors: Evgin Tuba , Turgut Alpaslan , Hamaoui Georges , Špitalský Zdeno , Horny Nicolas , Altay Lütfiye , Chirtoc Mihai , Omastová Mária
Published: April 2021

High-density polyethylene (HDPE)-based hybrid nanocomposites containing graphene nanoplatelets (GnPs) and multiwall carbon nanotubes (MWCNTs) were fabricated using melt mixing followed by compression molding. The influences of size and weight ratio of both carbon-based nanofillers on the electrical, thermal, and mechanical properties of hybrid nanocomposites were evaluated. This study proves that the size and weight ratio of carbon-based nanofillers play a critical role in determining these properties. The optimum size and weight ratio of GnPs and MWCNTs are determined at the maximum achieved enhancement for each property. The HDPE-based nanocomposites containing GnPs with larger surface area and MWCNTs with higher aspect ratio display the highest electrical conductivity at GnPs/MWCNTs weight ratio of 2/3. The combination of GnPs with larger surface area and MWCNTs with lower aspect ratio provides the maximum Young’s modulus enhancement of hybrid nanocomposites at 1/4 weight ratio of GnPs and MWCNTs. The nanocomposite containing GnPs with the largest lateral size and MWCNTs with a higher aspect ratio at a 3/2 weight ratio exhibits the highest thermal conductivity. Also, at around the percolation threshold of GnPs, the incorporation of MWCNTs with larger aspect ratio into the HDPE-based nanocomposites containing GnPs with the largest lateral size shows a distinct synergic effect on the thermal conductivity and Young’s modulus, while an additive effect on the electrical conductivity and thermal stability.
Cell surface nucleolin as active bait for nanomedicine in cancer therapy: a promising option
Authors: Ferrara Benedetta , Belbekhouche Sabrina , Habert Damien , Houppe Claire , Vallée Benoit , Bourgoin-Voillard Sandrine , Cohen José L , Cascone Ilaria , Courty José
Published: April 2021

Conventional chemotherapy used against cancer is mostly limited due to their non-targeted nature, affecting normal tissue and causing undesirable toxic effects to the affected tissue. With the aim of improving these treatments both therapeutically and in terms of their safety, numerous studies are currently being carried out using nanoparticles (NPs) as a vector combining tumor targeting and carrying therapeutic tools. In this context, it appears that nucleolin, a molecule over-expressed on the surface of tumor cells, is an interesting therapeutic target. Several ligands, antagonists of nucleolin of various origins, such as AS1411, the F3 peptide and the multivalent pseudopeptide N6L have been developed and studied as therapeutic tools against cancer. Over the last ten years or so, numerous studies have been published demonstrating that these antagonists can be used as tumor targeting agents with NPs from various origins. Focusing on nucleolin ligands, the aim of this article is to review the literature recently published or under experimentation in our research team to evaluate the efficacy and future development of these tools as anti-tumor agents.