bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of parental depression on the problem behaviour and academic performance of children with asthma
Authors: Han Jeong‐Won , Kim Jung Min , Lee Hanna
Published: June 2020

Aim

This study attempts to determine the factors affecting problem behaviour and academic performance of children with asthma.

Design

This is a cross‐sectional study used actor and partner interdependence model.

Methods

Data of 236 children and their parents from the 10th Panel Study on Korean Children were used, and analysis was performed using SPSS 20.0 and AMOS 20.0. We have received panel data from the Korea Institute of Child Care and Education on April 10th, 2019.

Results

Parental depression had actor and partner effects on marital conflict, and marital conflict perceived by the father had actor and partner effects on parent–child interactions, while marital conflict perceived by the mother had only actor effect on parent–child interactions. Parent–child interaction perceived by both fathers and mothers was found to affect the problem behaviour of children. The problem behaviour of children affects academic performance.
(S)‐4‐Amino‐5‐phenoxypentanoate designed as a potential selective agonist of the bacterial transcription factor GabR
Authors: Catlin Daniel S. , Reidl Cory T. , Trzupek Thomas R. , Silverman Richard B. , Cannon Brian L. , Becker Daniel P. , Liu Dali
Published: June 2020

Addressing molecular recognition in the context of evolution requires pursuing new molecular targets to enable the development of agonists or antagonists with new mechanisms of action. Disruption of transcriptional regulation through targeting transcription factors that regulate the expression of key enzymes in bacterial metabolism may provide a promising method for controlling the bacterial metabolic pathways. To this end, we have selectively targeted a bacterial transcription regulator through the design and synthesis of a series of γ‐aminobutyric acid (GABA) derivatives, including (S)‐4‐amino‐5‐phenoxypentanoate (4‐phenoxymethyl‐GABA), which are based on docking insights gained from a previously‐solved crystal structure of GabR from Bacillus subtilis. This target was selected because GabR strictly controls GABA metabolism by regulating the transcription of the gabT/D operon. These GabR transcription modulators are selective for the bacterial transcription factor GabR and are unable to bind to structural homologs of GabR due to distinct steric constraints. We have obtained a crystal structure of 4‐phenoxymethyl‐GABA bound as an external aldimine with PLP in the effector binding site of GabR, which suggests that this compound is capable of binding and reacting in the same manner as the native effector ligand. Inhibition assays demonstrate high selectivity of 4‐phenoxymethyl‐GABA for bacterial GabR versus several selected eukaryotic enzymes. Single‐molecule fluorescence resonance energy transfer (smFRET) experiments reveal a ligand‐induced DNA distortion that is very similar to that of the native effector GABA, suggesting that the compound functions as a potential selective agonist of GabR.
Morphology‐Controlled Molybdenum Disulfide/Candle Soot Carbon Composite for High‐Performance Supercapacitor
Authors: Sangabathula Omkar , Potphode Darshna , Sharma Chandra S.
Published: June 2020

Facile assembly of robust electrodes with excellent electrochemical performances is still challenging yet consequential for supercapacitor applications. Although molybdenum disulfide (MoS2) has versatile properties, restacking of molybdenum layers and poor intrinsic conductivity restrict to explore it for electrochemical applications. Herein to address these challenges, we utilized candle soot derived carbon to fabricate MoS2/Carbon (C) nanocomposite through a simple hydrothermal synthesis method. The prepared composite delivered specific capacitance of 452.7 Fg−1 at a current density of 1 Ag−1 in 3 M KOH electrolyte and profound capacity retention and coulombic efficiency of 94.8% and 93.7% after 10,000 charge‐discharge cycles respectively. Furthermore, we fabricated asymmetric supercapacitor device using MoS2/C as the positive electrode and candle soot derived carbon as a negative electrode (MoS2/C // C) which showed excellent energy and power density values with an impressive capacitance retention of 100% over 10,000 cycles. The exceptional electrochemical performance of MoS2/Carbon composite thus indicates the potential application for high‐performance supercapacitor devices.
Development of Highly Efficient Dual‐AAV Split Adenosine Base Editor for In Vivo Gene Therapy
Authors: Chen Yuxi , Zhi Shengyao , Liu Weiliang , Wen Jinkun , Hu Sihui , Cao Tianqi , Sun Hongwei , Li Yang , Huang Li , Liu Yizhi , Liang Puping , Huang Junjiu
Published: June 2020

The adenosine base editor (ABE) is able to catalyze A•T to C•G conversion efficiently and precisely in vivo, representing a new method for gene therapy. Adeno associated virus (AAV) is a well‐studied vector for gene delivery in vivo. However, due to the limited loading capacity of AAV vector (≈4800 bp), it is difficult to package ABE (≈5400 bp) into a single AAV. To tackle this problem, ABE can be split into two smaller parts through intein‐mediated protein trans‐splicing. Here, 14 different split sites of nCas9 (Cas9 nickase) in combination with three different inteins (Mxe, Npu, and Rma) are screened through a GFP‐based reporter system to identify novel split‐ABEs. After infecting HEK293T and HeLa cells with dual AAVs, two split‐ABEs (split‐ABE‐Rma573 and split‐ABE‐Rma674) that can edit the target gene efficiently are identified. Furthermore, these dual‐AAV split‐ABEs can effectively disrupt the splicing acceptor of PCSK9 in mouse liver and the splicing donor of NR2E3 in mouse retina through AI‐MAST strategy. This study provides two new split‐ABEs to investigate gene function in vivo and in gene therapy, representing a new method to treat diseases by precisely repairing point mutations or inactivating genes through the AI‐MAST strategy.
Visualizing the In Vivo Evolution of an Injectable and Thermosensitive Hydrogel Using Tri‐Modal Bioimaging
Authors: Chen Xiaobin , Zhang Jiulong , Wu Kaiting , Wu Xiaohui , Tang Jingyu , Cui Shuquan , Cao Dinglingge , Liu Ruili , Peng Chen , Yu Lin , Ding Jiandong
Published: June 2020

Degradability of biomaterials brings many opportunities as well as great challenges to their clinical applications. However, reports of systematic in vivo biodegradation are rather limited due to lack of adequate methodology for real‐time observations. Herein, a tri‐modal bioimaging technique is developed, enabling real time monitoring of biodegradation of synthetic polymers in vivo. The demonstrated material is a successful preclinical poly(lactic acid‐co‐glycolic acid)‐b‐poly(ethylene glycol)‐b‐poly(lactic acid‐co‐glycolic acid) thermosensitive hydrogel that undergoes a spontaneous sol–gel transition upon heating. A macromolecular fluorescence probe and a contrast agent of magnetic resonance imaging (MRI) are designed and synthesized. After subcutaneous injection of the hydrogel containing the two probes into mice, the degradation behaviors of the material are longitudinally and noninvasively tracked via the collaborative application of ultrasound, fluorescence, and MRI. Integrating the noninvasive imaging with the traditional anatomic observations, a three‐stage degradation mechanism of such a hydrogel is proposed for the first time. Also, the dissolved polymers and degradation products in the body are mainly eliminated via liver, gallbladder, and spleen. This work has great value for promoting the future clinical application of these kind of promising hydrogels. Meanwhile, this technological platform provides beneficial inspiration and methodology to investigate in vivo fate of biomaterials.
Highly Efficient Nonfullerene Organic Photovoltaic Devices with 10% Power Conversion Efficiency Enabled by a Fine‐Tuned and Solution‐Processed Hole‐Transporting Layer
Authors: Teng Nai-Wei , Li Chia-Hua , Lo Wei-Chun , Tsai Yi-Sheng , Liao Chuang-Yi , You Yun-Wen , Ho Hsiuan-Lin , Li Wei-Long , Lee Chun-Chieh , Lin Wei-Chun , Chang Yi-Ming
Published: June 2020

Solution‐processable hole‐transporting materials are demonstrated to improve the performance of nonfullerene‐based organic photovoltaic devices in an inverted structure. A vanadium oxide (VOX) precursor, used as a sol–gel, is mixed with commercial poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) to form a well‐dispersed VOX:PEDOT:PSS solution. The work function and molecular distribution of the VOX:PEDOT:PSS thin film are examined by ultraviolet photoelectron spectroscopy (UPS) and time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS), respectively. Unlike conventional PEDOT:PSS, VOX:PEDOT:PSS not only is compatible with highly hydrophobic photoactive layers but also aligns well with the highest occupied molecular orbital (HOMO) level of the polymer donor, reaching a power conversion efficiency of 10% (≈100% boost) and achieving an excellent device stability.
Efficient and Stable Tin Perovskite Solar Cells Enabled by Graded Heterostructure of Light‐Absorbing Layer
Authors: Wu Tianhao , Cui Danyu , Liu Xiao , Meng Xiangyue , Wang Yanbo , Noda Takeshi , Segawa Hiroshi , Yang Xudong , Zhang Yiqiang , Han Liyuan
Published: June 2020

Lead‐free tin perovskite solar cells (TPSCs) have attracted widespread attention in recent years due to their low toxicity, suitable bandgap, and high carrier mobility. However, the photovoltage and efficiency of TPSCs are still much lower than those of the lead counterparts because of the high trap density and unfavorable band structure in tin perovskite films. To overcome these issues, efficient and stable TPSCs with a graded heterostructure of light‐absorbing layer are reported, in which the narrow‐bandgap tin perovskite dominates at the bulk, whereas the wide‐bandgap tin perovskite is distributed with a gradient from bulk to surface. This heterostructure can selectively extract the photogenerated charge carriers at the perovskite/electron transport layer interface, reduce the density of trap states, and impede the oxidation process of Sn2+ to Sn4+ in air. As a consequence, this graded heterostructure of tin perovskite layer contributes to an increase of 120 mV in the open‐circuit voltage and a maximum power conversion efficiency of 11% for TPSCs with longer operational stability.
Thence the moment of momentum
Authors: Müller Wolfgang H. , Rickert Wilhelm , Vilchevskaya Elena N.
Published: June 2020

Fifty years have passed since Truesdell's seminal paper on the origin and status of the balance for the moment of momentum was published in ZAMM. It is time to take stock: Important new developments in the theory of generalized continua with internal degrees of freedom and some fascinating fundamental applications need to be pointed out. Is there new evidence from classical papers regarding its independence from the balance of linear momentum? Can micropolar theory be used to “explain” electromagnetism? How is the conservation of the moment of momentum viewed in today's physics textbooks? In this paper an attempt is made to answer these and many more interesting questions.
Evidence-Based PET for Infectious and Inflammatory Diseases
Authors: Treglia Giorgio , Muoio Barbara
Published: June 2020

Nuclear medicine techniques are non-invasive tools that can early detect pathophysiological changes in affected tissues in patients with inflammatory or infectious diseases. These changes usually occur before clinical onset of symptoms and before the development of anatomical changes detected by radiological techniques [1, 2]. Currently, hybrid imaging techniques as positron emission tomography/computed tomography (PET/CT) may provide functional and morphological information for early diagnosis of infectious and inflammatory diseases [1, 2].
Double Yang-Baxter deformation of spinning strings
Authors: Hernández Rafael , Ruiz Roberto
Published: June 2020

Abstract

We study the reduction of classical strings rotating in the deformed three- sphere truncation of the double Yang-Baxter deformation of the AdS
3
×S
3
×T
4 background to an integrable mechanical model. The use of the generalized spinning-string ansatz leads to an integrable deformation of the Neumann-Rosochatius system. Integrability of this system follows from the fact that the usual constraints for the Uhlenbeck constants apply to any deformation that respects the isometric coordinates of the three-sphere. We construct solutions to the system in terms of the underlying ellipsoidal coordinate. The solutions depend on the domain of the deformation parameters and the reality conditions of the roots of a fourth order polynomial. We obtain constant-radii, giant-magnon and trigonometric solutions when the roots degenerate, and analyze the possible solutions in the undeformed limit. In the case where the deformation parameters are purely imaginary and the polynomial involves two complex-conjugated roots, we find a new class of solutions. The new class is connected with twofold giant-magnon solutions in the degenerate limit of infinite period.
Information recovery from pure state geometries in 3D
Authors: Hulík Ondřej , Raeymaekers Joris , Vasilakis Orestis
Published: June 2020

Abstract

It is a well-studied phenomenon in AdS3/CFT2 that pure states often appear ‘too thermal’ in the classical gravity limit, leading to a version of the information puzzle. One example is the case of a heavy scalar primary state, whose associated classical geometry is the BTZ black hole. Another example is provided by a heavy left-moving primary, which displays late time decay in chiral correlators.

In this paper we study a special class of pure state geometries which do not display such information loss. They describe heavy CFT states created by a collection of chiral operators at various positions on the complex plane. In the bulk, these take the form of multi-centered solutions from the backreaction of a collection of spinning particles, which we construct for circular distributions of particles. We compute the two-point function of probe operators in these backgrounds and show that information is retrieved.

We observe that the states for which our geometric picture is reliable are highly extended star-like objects in the bulk description. This may point to limitations of semiclassical microstate geometries for understanding the information puzzle and to the need for including quantum effects.
Synthesis and structure confirmation of 2,4-disubstituted thiazole and 2,3,4-trisubstituted thiazole as thiazolium bromide salts
Authors: Hassan Alaa A. , Mohamed Nasr K. , Aly Ashraf A. , Tawfeek Hendawy N. , Bräse Stefan , Nieger Martin
Published: June 2020

The synthesis of 4-substituted 2-(2-arylhydrazinyl)thiazol-3-ium bromides and 4-aryl-2-(substituted amino)-3-(phenylamino)thiazol-3-ium bromide derivatives in high yields from the interaction of mono- and di-substituted thiosemicarbazides with phenacyl bromide derivatives is reported. The synthesized products have been elucidated using various spectroscopic tools such as IR, NMR, and mass spectrometry. Also the structure of three of the obtained compounds have been confirmed using X-ray crystallographic analyses, which showed that compounds 2-[2-(2,4-dinitrophenyl)hydrazinyl]-4-phenylthiazol-3-ium bromide and 4-phenyl-2,3-bis(phenylamino)thiazol-3-ium bromide crystals have a monoclinic shape and belonged to space group P21/c, whereas the crystals of 4-phenyl-2-(2-tosylhydrazinyl)thiazol-3-ium bromide show an orthorhombic shape with the space group Pbca

Graphic abstract
Reinforcement learning for robotic assembly of fuel cell turbocharger parts with tight tolerances
Authors: Aschersleben Franziska , Griemert Rudolf , Gabriel Felix , Dröder Klaus
Published: June 2020

The efficiency of a fuel cell is not only dependent on the stack, but also to a large extent on the turbocharger, which is responsible for providing the required airflow. Since the individual components, especially those of the rotor, are subject to high demands on manufacturing accuracy, it is crucial to ensure a precise and robust assembly. In order to achieve a scalable assembly process, this paper presents a method for a robot-based assembly of the rotationally symmetric components of the rotor. The assembly task has been reduced to the two essential problems: search and insertion. On this basis, a system was developed, which is able to learn the joining process independently and compensate for positioning inaccuracies with the help of reinforcement learning in combination with a position-controlled robot. The applied reinforcement learning strategy is based on the measurement data of a 6-axis force/torque sensor, with which the current contact state can be evaluated and a decision for the next step can be made. The experimental verification shows that an automation of the assembly process is possible with the proposed strategy. The robot is able to perform the search operation successfully, whereas limitations to the achievable accuracies of the insertion process could be found.
A Note on the Evolution of the Whitney Sphere Along Mean Curvature Flow
Authors: Viana Celso
Published: June 2020

We study the evolution of the Whitney sphere along the Lagrangian mean curvature flow. We show that equivariant Lagrangian spheres in $${{\mathbb {C}}^n}$$

C

n

satisfying mild geometric assumptions collapse to a point in finite time and the tangent flows converge to a Lagrangian plane with multiplicity two.
Evaluation of satellite precipitation products using HEC-HMS model
Authors: Belayneh Alemshet , Sintayehu Gashaw , Gedam Kibrit , Muluken Tirunesh
Published: June 2020

Accurate measurement of precipitation is vital to investigate the spatial and temporal patterns of precipitation at various scales for rainfall-runoff modeling. However, accurate and consistent precipitation measurement is relatively sparse in many developing countries like Ethiopia. Nevertheless, satellite precipitation products may serve as important inputs for modeling in an area with scarce field data for a wide range of hydrological applications. In this study we evaluate the high-resolution satellite rainfall products for hydrological simulation, the Climate Hazards Group Infrared Precipitation with Stations (CHIRPS) and Tropical Rainfall Measuring Mission Multisatellite Precipitation Analysis (TMPA_3B42v7) satellite rainfall products for stream flow simulation at daily temporal and 0.25° × 0.25° spatial resolution. The study area is located in Dabus watershed, Abbay basin, Ethiopia. We applied a nonlinear power law to remove the systematic error of satellite precipitation estimates for input into HEC-HMS hydrological model for runoff generation. The performance of the satellite rainfall and hydrological model was evaluated using Nash–Sutcliffe efficiency (ENS), coefficient of determination (R2), relative volume error (RVE), and percentage error of peak flow objective functions. The result of HEC-HMS model performance revealed R2 of 0.78, ENS of 0.69 for CHIRPS_2 and R2 of 0.79, ENS of 0.76 for TMPA_3B42v7 satellite rainfall products during calibration periods. Our result indicated that the HEC-HMS model well predicated catchment runoff for both satellite precipitation products. The study shows that the model performance was significantly improved when bias-corrected satellite rainfall input replaced than the original uncorrected satellite products. Overall, our study showed that gauge-based simulation outperformed than satellite in terms of all objective functions over the study area.
Recent advances in stimuli-responsive drug release and targeting concepts using mesoporous silica nanoparticles
Authors: Abdo Ghada G. , Zagho Moustafa M. , Khalil Ashraf
Published: June 2020

Being a developed and promising approach, nanotechnology has attracted a lot of attention in biomedical and pharmaceutical therapy applications. Among nanostructured materials, mesoporous silica nanoparticles (MSNs) are effectively used as nanocarriers for drug delivery systems. MSNs can be tailored-designed by different synthetic techniques. Their morphological characteristics dictate the type of application of such materials. Recently, polymer-based materials have been employed to functionalize the MSNs surface. These modified nanocarriers are loaded with the drug and can unload their “cargo” upon exposure to either endogenous or exogenous types of stimuli. In this study, different targeting concepts, including passive, active, vascular, nuclear, and multistage targeting, are discussed.
Efficacy of Imbalanced Data Handling Methods on Deep Learning for Smart Homes Environments
Authors: Hamad Rebeen Ali , Kimura Masashi , Lundström Jens
Published: June 2020

Human activity recognition as an engineering tool as well as an active research field has become fundamental to many applications in various fields such as health care, smart home monitoring and surveillance. However, delivering sufficiently robust activity recognition systems from sensor data recorded in a smart home setting is a challenging task. Moreover, human activity datasets are typically highly imbalanced because generally certain activities occur more frequently than others. Consequently, it is challenging to train classifiers from imbalanced human activity datasets. Deep learning algorithms perform well on balanced datasets, yet their performance cannot be promised on imbalanced datasets. Therefore, we aim to address the problem of class imbalance in deep learning for smart home data. We assess it with Activities of Daily Living recognition using binary sensors dataset. This paper proposes a data level perspective combined with a temporal window technique to handle imbalanced human activities from smart homes in order to make the learning algorithms more sensitive to the minority class. The experimental results indicate that handling imbalanced human activities from the data-level outperforms algorithms level and improved the classification performance.
Customer Engagement: A Systematic Review and Future Research Priorities
Authors: Ng Sylvia C. , Sweeney Jillian C. , Plewa Carolin
Published: June 2020

In a marketplace characterised by more demanding and more active customers, both academics and practitioners have become increasingly drawn to the concept of customer engagement (CE). Despite the recognised importance of CE, research in this area remains fragmented with a variety of definitions and conceptualisations evident in the literature. This is concerning, as a lack of alignment may result in misinterpretations, causing further divergence in future research. This paper thus offers a systematic review of the extant literature on customer engagement dated from 2009-2018, reflecting: (i) leading conceptualisations and manifestations of CE, (ii) customer- and firm-related CE antecedents, as well as (iii) CE outcomes from the customer and firm perspectives. Hence, it provides conceptual, methodological and thematic guidance to scholars studying CE. Furthermore, we discuss an extensive list of research priorities, developed based on future-focused contributions of 12 distinguished international experts, providing a strong foundation for shaping CE literature in future.
When Giving is Good for Encouraging Social Entrepreneurship
Authors: Le Truc Thanh , Nguyen Thi Nguyet Que , Tran Quan Ha Minh
Published: June 2020

We develop a cognitive-affect model of social entrepreneurship that begins with empathy (i.e. perspective taking and empathic concern) and progresses through prosocial behavior to social entrepreneurship intention. We further propose two contingencies – namely entrepreneurial opportunity evaluation and exploitation - that moderate the proposed relationships. We verify theses effects with a sample of 537 respondents. Results suggest that prosocial behavior mediates the relationship between empathy (perspective taking and empathic concern) and social entrepreneurial intention. We also find that opportunity evaluation and opportunity exploitation moderate this mediating pathway.
A manifesto for increasing access to data in engineering
Authors: Dodds Leigh , L’Hénaff Pauline , Maddison James , Yates Deborah
Published: June 2020

This paper introduces a set of principles that articulate a shared vision for increasing access to data in the engineering and related sectors. The principles are intended to help guide progress toward a data ecosystem that provides sustainable access to data, in ways that will help a variety of stakeholders in maximizing its value while mitigating potential harms. In addition to being a manifesto for change, the principles can also be viewed as a means for understanding the alignment, overlaps and gaps between a range of existing research programs, policy initiatives, and related work on data governance and sharing. After providing background on the growing data economy and relevant recent policy initiatives in the United Kingdom and European Union, we then introduce the nine key principles of the manifesto. For each principle, we provide some additional rationale and links to related work. We invite feedback on the manifesto and endorsements from a range of stakeholders.
THE COMPLEXITY OF HOMEOMORPHISM RELATIONS ON SOME CLASSES OF COMPACTA
Authors: KRUPSKI PAWEŁ , VEJNAR BENJAMIN
Published: June 2020

We prove that the homeomorphism relation between compact spaces can be continuously reduced to the homeomorphism equivalence relation between absolute retracts, which strengthens and simplifies recent results of Chang and Gao, and Cieśla. It follows then that the homeomorphism relation of absolute retracts is Borel bireducible with the universal orbit equivalence relation. We also prove that the homeomorphism relation between regular continua is classifiable by countable structures and hence it is Borel bireducible with the universal orbit equivalence relation of the permutation group on a countable set. On the other hand we prove that the homeomorphism relation between rim-finite metrizable compacta is not classifiable by countable structures.
Equations of some plane figures
Authors: Buritica Andres
Published: June 2020

The solution set of an equation f(x,y) = g(x,y) over ℝ2 is the set of all pairs of real numbers (x,y) such that the equation holds.

This article finds equations whose solution sets are the boundaries (in Cartesian coordinates) of different shapes.
Viral (per)versions of power in Paolo Sorrentino's diptych Loro
Authors: Mariani Annachiara
Published: June 2020

This article examines Paolo Sorrentino's portrayal of moral degradation and pursuit of power in his twin biopics about Silvio Berlusconi: Loro 1 and Loro 2 (2018). It does so by performing a psychological reading of Sorrentino's representation of Berlusconi, as someone suffering from a personality disorder characterised by excessive power striving. It argues that this obsession with power also affects most of the films’ characters, who become obsessed with entering Berlusconi's inner circle – the pinnacle of wealth and power in a neoliberal society. In particular, it argues that their power striving circulates ‘virally’ in the film's narrative; the characters are willing to do anything to befriend their idol and attain absolute power. The ensuing analysis shows that Sorrentino's portrayal of Berlusconi – as the embodiment of a highly dysfunctional and obsessive, viral quest for power – comes to represent the deep pervasiveness of corruption, hedonism and commodification that marked the Second Republic.
Time Signatures: The Temporality of Monuments in Early and Middle Neolithic Britain
Authors: Bradley Richard
Published: June 2020

Analysis of radiocarbon dates has established the chronological contexts of three kinds of Neolithic monument in Britain: long mounds or long cairns, causewayed enclosures, and cursuses. It is more difficult to appreciate how such structures developed over time. The building of a barrow or cairn was sometimes the final act in a place that had already experienced a longer history. The construction of the monument brought activities to an end, and the site was effectively closed. Individual sequences were shorter than once thought but might be repeated at different locations over several hundred years.

On the other hand, the construction of causewayed enclosures according to a widely accepted template occurred almost simultaneously. Once those earthworks were established some went out of use, but a few others were adapted and changed so that they could play an increasing variety of roles over a longer period. The same contrasts are illustrated by cursuses. Timber structures in the north had finite histories before they decayed or were destroyed by fire, whilst earthworks had a wider distribution and enjoyed a longer currency. A similar approach might shed light on later monuments, including henges, stone circles, and round barrows. It is important to consider how the chronologies of all these structures are related to past conceptions of time.
Disentangling the Impact of Civil Association Membership on Political Participation: Evidence from Swedish Panel Data
Authors: Aggeborn Linuz , Lajevardi Nazita , Nyman Pär
Published: June 2020

What is the effect of membership in civil associations on political participation? Membership has been linked to providing social capital and personal networks, which in turn help citizens more easily navigate politics. Yet this link is empirically complex, since politically interested individuals self-select into networks and associations. This research note addresses the impact of membership on different forms of political participation using a panel survey from Sweden that distinguishes between passive and active membership in various types of associations. The baseline results reaffirm a strong association between membership and political participation. The survey's panel dimension is exploited to reveal that earlier scholarship has likely overstated the robustness of membership's participatory effects. Rather, the remaining impact of association membership in the panel specification is mainly driven by types of associations for which the highest degree of selection behaviour is expected.
‘I shall miss the company’: participants’ reflections on time-limited day centre programming
Authors: Hagan Robert J. , Manktelow Roger
Published: June 2020

The social needs of frail or isolated older people are sometimes aided by referrals to day centres in the United Kingdom. Since the late 1940s, day centres have had a role to play promoting socialisation in later life. Additionally, attendance at day centres is often open ended, with participants only leaving due to moving to a nursing home or dying. In this study, the views of those attending time-limited day centre programmes in seven day centres in Northern Ireland have been sought in relation to their thoughts about the service as well as how they feel when it ends. Seventeen participants completed diaries for the programme duration and/or engaged in an interview process. Participants reflected on the social and educational benefits of attending but also recognised impositions in the centres that impinged upon individual choices and also the length of time they could remain. This study reveals that, in order to maintain socialisation, time-limited programmes must have clear follow-on strategies for participants. Additionally, respondents’ experiences reflect that a paternalistic model of care delivery remains in place that, whilst restrictive, reveals that access to the service is more specialised and not universal. Nevertheless, should day centres wish to remain relevant, it is important that service users are fully consulted about their desires and choices within the setting.
Quality of economic evaluations of ventricular assist devices: A systematic review
Authors: Fontenay Sarah , Catarino Lionel , Snoussi Soumeya , van den Brink Hélène , Pineau Judith , Prognon Patrice , Martelli Nicolas
Published: June 2020

Objective

Because of a lack of suitable heart donors, alternatives to transplantation are required. These alternatives can have high costs. The aim of this study was to perform a systematic review of cost-effectiveness studies of ventricular assist devices (VADs) and to assess the level of evidence of relevant studies. The purpose was not to present economic findings.

Methods

A systematic review was performed using four electronic databases to identify health economic evaluation studies dealing with VADs. The methodological quality and reporting quality of the studies was assessed using three different tools, the Drummond, Cooper, and CHEERS (Consolidated Health Economic Evaluation Reporting Standards) checklists.

Results

Of the 1,258 publications identified, thirteen articles were included in this review. Twelve studies were cost–utility analyses and one was a cost-effectiveness analysis. According to the Cooper hierarchy scale, the quality of the data used was heterogeneous. The level of evidence used for clinical effect sizes, safety data, and baseline clinical data was of poor quality. In contrast, cost data were of high quality in most studies. Quality of reporting varied between studies, with an average score of 17.4 (range 15–19) according to the CHEERS checklist.

Conclusion

The current study shows that the quality of clinical data used in economic evaluations of VADs is rather poor in general. This is a concern that deserves greater attention in the process of health technology assessment of medical devices.
A Scanning Electron Microscopic Study of the Nephrotic Kidney
Authors: Andrews Peter M.
Published: June 2020

Scanning electron microscopy, supplemented with light microscopy and transmission electron microscopy, was used to study aminonucleoside nephrosis in rats. Aminonucleoside nephrosis was induced by daily injections of puromycin aminonucIeoside (1.5 mg/10 gm). When the rats exhibited considerable proteinuria (10 mg/ml after 14 days of injections), their kidneys were fixed by vascular perfusion, sectioned and critical point dried.
Ultrastructure of Bronchiolo-Alveolar Carcinoma Favoring a Bronchiolar Origin
Authors: Smith Marilyn N. , Greenberg S. Donald , Spjut Harlan J.
Published: June 2020

Bronchiolo-alveolar carcinoma is a well differentiated adenocarcinoma originating in the periphery of the lung. Tumor epithelium is supported principally by the stroma of the alveolar walls.

The cell of origin remains in doubt. The tumor has been called alveolar cell carcinoma suggesting an origin from the alveolar epithelial lining. Cells resembling Type II granular pneumocytes of the alveolar wall have been shown to be the cell forming lung tumors in animals and four reports of EM studies in human tumors implicated the same cell. An EM study of eleven cases by Kuhn shows a bronchiolar origin and casts doubt that the granular pneumocytes are the neoplastic cells. We have studied five cases with EM and have observed what we believe is convincing evidence that these tumors are bronchiolar in origin.
Intravascular Degranulation of Neutrophils in Dog Lungs Secondary to Experimental Acute Pancreatitis
Authors: Bockman Dale E. , Schiller William R. , Suriyapa Chinda , Mutchler John H. W. , Anderson Marion C.
Published: June 2020

Previous work from this laboratory has shown the fine structural changes which occur in the pancreas during the early stages of experimental pancreatitis induced by retrograde injection of purified pancreatic enzymes. Local inflammatory processes in the pancreas include invasion of parenchyma by neutrophils and eosinophils, edema, intravascular clotting, hemorrhage, and exit of fluid and cellular debris through lymphatic vessels.

Many secondary complications may follow pancreatitis. The most common secondary complication is pulmonary involvement, including pleural effusion of fluid containing high levels of amylase and lipase, and pneumonitis. The present study concentrates on the fine structure of the lung in dogs with experimental pancreatitis in an attempt to determine what factors might contribute to secondary pulmonary involvement.
Use of Calcium Ion as an Electron Microscopic Tracer for Injection into Blood and Cerebrospinal Fluid
Authors: Milhorat T. H. , Davis D. A. , Hammock M. K.
Published: June 2020

Although ions are much too small to be directly visualized with the electron microscope, the movement of exogenously administered calcium ion can be shown by a simple precipitation technique in vivo. The technique requires that the precipitating solution (in this case, phosphate fixative) be injected prior to sacrificing and by the same route used for injecting the ion to assure prompt reaction and optimal localization. The distribution of the ion is then revealed by an electron-dense crystalline deposit (calcium phosphate).
Role of Golgi Apparatus in the Formation of Plant Slimes, Cuticles and Extraneous Wall Material
Authors: Mollenhauer Hilton H.
Published: June 2020

Cell walls are fundamentally involved in many aspects of plant biology including the morphology, growth, and development of plant cells and the interactions between plant hosts and their pathogens. Intuitively, one can recognize that these wall properties result from the sum total of the various components of which the wall is composed and that there are classes of substances each of which impart a characteristic property to the cell wall.
Scanning Electron Microscopy of Ethanol Infiltrated Freeze-Fractured Cell Pellets
Authors: Henk William G. , Spurlock Ben O.
Published: June 2020

The increased depth of focus and superior resolving power of the scanning electron microscope provide advantages over the light microscope in viewing the external morphology of cultured cells and protists. Internal structures have, however, proved more difficult to observe. Freeze drying adequately preserves surface structures but results in poorly preserved cytoplasmic elements due to ice crystal damage. Critical point drying results in good preservation of both surface and cytoplasmic fine structure. Attempts to cut or break critical point dried material, however, result in plastic deformation of the cells. Humphreys, et al, recently introduced freeze fracturing of ethanol infiltrated tissues for biological scanning electron microscopy. We have modified and applied their technique and obtained similar results with Paramecium sp. obtained from mass cultures.
An Efficient Statistic for Determining the Diameter of Thin Sectioned Uniform Spheres from Measurements of Biological Samples
Authors: Schucany W. R. , Kelsoe G. H. , Allison V. F.
Published: June 2020

Accurate estimation of the size of spheroid organelles from thin sectioned material is often necessary, as uniquely homogenous populations of organelles such as vessicles, granules, or nuclei often are critically important in the morphological identification of similar cell types. However, the difficulty in obtaining accurate diameter measurements of thin sectioned organelles is well known. This difficulty is due to the extreme tenuity of the sectioned material as compared to the size of the intact organelle. In populations where low variance is suspected the traditional method of diameter estimation has been to measure literally hundreds of profiles and to describe the “largest” as representative of the “approximate maximal diameter”.
A Method of Direct Visualization of Plant Cell Organelles for Scanning Electron Microscopy
Authors: Woods Philip S. , Ledbetter Myron C.
Published: June 2020

Identification of plant and animal cell organelles by scanning electron microscopy (SEM) has been demonstrated by several workers using a variety of methods. In one method Tanaka and lino exposed contents of fixed animal cells by cracking chilled tissues infiltrated with epoxy resin. Cracked tissues were dried and coated to reveal a number of cell organelles by small surface irregularities in an otherwise smooth break. We have achieved a more nearly in toto visualization of cell organelles by SEM using uncoated specimens fractured in chilled resin. This was done by rendering fixed tissues electrically conductive by the ligand-mediated osmium binding technique of Kelley, et al, prior to cracking. Unlike previous methods based on surface topography or sections, this procedure takes advantage of intrinsic secondary emissions from various organelles (Fig. 1) as a result of heavy osmium binding.
Relations Between Fixation and Dehydration in Preserving Cell Morphology
Authors: Cohen Arthur L. , Shaykh M. Mashouf
Published: June 2020

Using Spirogyra spp. as sensitive test organisms, we have shown that conventional glutaraldehyde fixation (3% or 6% for one hour) resulted in distortion and shrinkage which was more severe if the graded concentrations of water/ethanol for dehydration were in rather large steps. Although external distortion was nearly eliminated by OSO4 postfixation and periodate decolorization, internal structure was degraded. To clarify the relations between fixation and graded dehydration, we used field-collected Spirogyra spp. (Figs. 2,3) later supplanted by a laboratory-grown strain* (Figs. 1,4,5). Fixatives were glutaraldehyde 2% and 5%; and OsO4 1%; all in 0.1 M PO4 buffer, approx. pH 7.2. All aqueous media had osmolalities calculated below that of Spirogyra cell sap.
In Vitro Induction of Crystals of MT Protein by Vinblastine-Colcemid in Mouse Spermatids
Authors: Wolosewick John J. , Bryan John H. D.
Published: June 2020

Early in spermiogenesis the manchette is rapidly assembled in a distal direction from the nuclear-ring-densities. The association of vesicles of smooth endoplasmic reticulum (SER) and the manchette microtubules (MTS) has been reported. In the mouse, osmophilic densities at the distal ends of the manchette are the organizing centers (MTOCS), and are associated with the SER. Rapid MT assembly and the lack of rough ER suggests that there is an existing pool of MT protein. Colcemid potentiates the reaction of vinblastine with tubulin and was used in this investigation to detect this protein.
Transmission and Scanning Electron Microscopy of the Follicle in the Human Ovary
Authors: Baccarini I. M.
Published: June 2020

Several ultrastructural studies demonstrated that the granulosa cells changed the structure since their differentiation, maturation and degeneration. However, little is known about the organization of the granulosa cells in the follicle for instance, the connection between the cells and cellular interchanges.

Fragments of ovary obtained from the surgery room were fixed in 3% buffered glutaraldehyde for scanning microscope and post-fixed in 1% buffered osmium tetroxide for electron microscopic studies.
Electron Diffraction of Wet Biological Membranes
Authors: Hui S.W. , Parsons D.F.
Published: June 2020

The development of the hydration stages for electron microscopes has opened up the application of electron diffraction in the study of biological membranes. Membrane specimen can now be observed without the artifacts introduced during drying, fixation and staining. The advantages of the electron diffraction technique, such as the abilities to observe small areas and thin specimens, to image and to screen impurities, to vary the camera length, and to reduce data collection time are fully utilized. Here we report our pioneering work in this area.
Human Red Cell Studies Using Scanning Electron Microscopy
Authors: Hainfeld J. , Isaacson M.
Published: June 2020

Membrane models for the human erthrocyte have been proposed as a result of chemical studies and some conventional electron microscope work. However, the distribution of specific membrane components (proteins, phospholipids, chloresterol and carbohydrates) is not completely known.

We have therefore undertaken a program to determine the potential usefulness of high resolution scanning microscopy in obtaining information concerning the molecular architecture of membranes.
Dark Field Electron Microscopy of Biological Membranes
Authors: Massover William H.
Published: June 2020

The increasing amount of knowledge about the macromolecular composition of biological membranes has led to the elaboration of newer models of membrane ultrastructure which have not yet been definitively evaluated by means of direct or indirect observations. The studies of model systems by Baumeister and Hahn emphasize that it might be possible to directly determine the placement of heavy metal atomic staining agents after these are specifically attached to a membrane. High resolution bright field imaging of very thin sections of embedded membranes has shown that the pair of dense lines which traditionally defines a unit membrane in positively stained specimens is formed by the superimposed projection of many individual stain “granules” having diameters down to 5-10Å.
Surface Ultrastructure of Gram (−) Bacteria: II. Determination of the Gram Reaction in Antartic Soil Bacteria by Electron Microscopy
Authors: Uydess I. L. , Vishniac Wolf
Published: June 2020

A modified negative staining technique (“OTPT”) has been described in the study of the surface topography of bacteria. This technique is useful in the rapid and accurate identification and discrimination of the Gram reaction of unknown bacteria under circumstances unfavorable to the direct application of the Gram stain. Cells of a particular genus exhibit the same basic topographical features independent of cell age, culture conditions or other cellular parameters.

Several pure cultures of unclassified bacteria isolated from Antarctic soils were prepared by the OTPT staining method. Although initial attempts employing the Gram stain were often inconclusive, this technique allowed a positive identification of all samples. Two organisms were chosen for more detailed study.
Intracisternal Tublar Reticulum in Dog Prostates
Authors: Hruban Z. , Lyon E.S. , Kieff E. , Wong T.W.
Published: June 2020

Our ultrastructural studies on the acute effects of herpes simplex virus type 2 on the prostates of dogs revealed that many endothelial cells and macrophages contained intracisternal tubular reticulum. Similar inclusions have been observed following infection with other herpes viruses. They occur frequently in tissues of patients with various diseases including autoimmune states, neoplasms and viral infections, and in tissues of normal animals. Intracisternal tubular reticulum has been observed in canine tissues, such as plasma-perfused kidneys, brain of dogs with distemper, a transmissible veneral tumor and a malignant lymphoma.
Electron Cytochemical Study of Carbon Dioxide Laser Effect on Rhesus Monkey Cornea
Authors: Tsou K. C. , Morris J. , Shawaluk P. , Stuck B. , Beatrice E.
Published: June 2020

While much is known regarding the effect of lasers on the retina, little study has been done on the effect of lasers on cornea, because of the limitation of the size of the material. Using a combination of electron microscope and several newly developed cytochemical methods, the effect of laser can now be studied on eye for the purpose of correlating functional and morphological damage. The present paper illustrates such study with CO2 laser on Rhesus monkey.
Morphological Characterization of Mycobacteriophage R1
Authors: Soloff B. L. , Rado T. A.
Published: June 2020

Mycobacteriophage R1 was originally isolated from a lysogenic culture of M. butyricum. The virus was propagated on a leucine-requiring derivative of M. smegmatis, 607 leu−, isolated by nitrosoguanidine mutagenesis of typestrain ATCC 607. Growth was accomplished in a minimal medium containing glycerol and glucose as carbon source and enriched by the addition of 80 μg/ ml L-leucine. Bacteria in early logarithmic growth phase were infected with virus at a multiplicity of 5, and incubated with aeration for 8 hours. The partially lysed suspension was diluted 1:10 in growth medium and incubated for a further 8 hours. This permitted stationary phase cells to re-enter logarithmic growth and resulted in complete lysis of the culture.