bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of soaking and tempering temperatures on high vanadium alloys for grinding media
Authors: Mabeba AD , Siyasiya CW
Published: November 2019

Vanadium produces the hardest carbides and can influence wear properties positively. However, due to the minerals’ price fluctuations as a result of the current economic climate, vanadium is currently expensive and seldom used in wear resistant materials despite its valuable properties. Nevertheless, it is still important to study the effects of vanadium carbides on wear properties and later compare the cost/durability ratio to the other currently used industrial alloys. Vanadium has been used as a secondary alloying element in high chromium cast iron and has produced positive results through the influence of orientation and morphology of the eutectic carbide M7C3. Vanadium carbides are known to be discontinuous, which is helpful with regards to impact properties. Vanadium carbides alone cannot maintain high macro-hardness values and for improved results carbon is needed to increase the strength of the matrix. In this paper, the influence of the soaking and tempering temperatures on hardness and wear properties in a high vanadium alloy, 1.91C-0.82Mn-0.96Si-0.90Ni-1.35Cr-0.25Mo-6.12V, were investigated. The soaking temperatures were 1150 and 1250°C while the tempering temperatures were varied at 100°C interval from 300 °C to 600 °C. It was found that soaking at 1250°C increased the amount of retained austenite, but at the same time also improved the wear resistance in as quenched condition as well as after tempering up to 500 °C.
Influence of Impeller Diameter on the Performance of Centrifugal pumps.
Authors: Matlakala M E , Kallon D V V , Mogapi K E , Mabelane I M , Makgopa D M
Published: November 2019

The impeller is the most important part of the centrifugal pump because it determines the flow or efficiency of the pump. The design of the impeller and its diameter are very essential when considering pump efficiency. The capacity of the pump is determined from the impeller vanes and channels. The three types of impellers include open impeller, enclosed impeller and semi-open impeller are each designed for a specific application. Impellers are made of cast iron or carbon steel and special alloys depending on their application. The research involves the study of the application of impellers in the centrifugal pumps used by Rand Water Company in Johannesburg. The paper considers how variations in the impeller diameter affect the performance of the centrifugal pump. Simulations were conducted at different diameters of the impeller. The impeller was modelled using AutoCAD and simulated using ANSYS software to determine the performance of the centrifugal pump on different diameters. Calculations were done to compare the results of simulation of the different diameters of 2000mm, 2200mm, and 2400mm. The results show that changing the diameter of a pump impeller affects the flow, head and input brake horsepower of the pump in different proportions. The centrifugal pump gives a high flow rate as the diameter of the impeller increases.
Influence of sintering temperature on densification, microstructure and mechanical properties of Ti-6Ni alloy developed via spark plasma sintering
Authors: Rominiyi A L , Shongwe M B , Maledi N B , Jeje S O , Babalola B J , Lepele P F
Published: November 2019

Titanium is used extensively in various engineering applications as a result of its unique physical, chemical and mechanical properties. However, the difficulty encountered in fabricating a fully densified titanium sample informed the introduction of alloying elements into the matrix in order to form a liquid phase and enhance sinterability. This work explored the influence of sintering temperature on the densification, microstructure and mechanical properties of Ti-6Ni alloy developed via spark plasma sintering at varying temperature from 850 °C to 1200 °C in a vacuum, under isothermal holding time, heating rate and applied pressure of 10 min, 100 °C/min and 50 MPa respectively. Characterization of the mixed powder and bulk sintered sample were carried out with the aid of scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscope (EDS) and X-ray diffraction (XRD). Relative density and hardness of the samples were determined following the Archimedes and Vickers method respectively. The SEM results indicated the presence of multiple phases in the microstructure of the sintered samples. These phases were confirmed by the EDS and XRD analysis results, as the intermetallics of Ti-Ni. Densifications above 98%, was achieved and the hardness values were found to vary with the densification of the sintered alloy, across the investigated sintering temperatures.
The effect of ternary alloying with vanadium on Ti-Pt shape memory alloys
Authors: Daswa P , Chikosha S , Mahlatji M L , Siyasiya C W
Published: November 2019

Ti-Pt alloys have attracted much research due to high transformation temperatures (1050°C) which makes them suitable for high temperature applications in automotive and aerospace industries. The binary alloy exhibits negligible shape memory effect and the amount of platinum (Pt) required to produce this alloy makes it very expensive which limits its practical application and commercialization. Ternary alloying of Ti-Pt could lead to solid solution strengthening and improved shape memory properties. Furthermore, ternary alloying by replacing Pt could reduce the cost of the alloy. However, it could lead to changes in the microstructure, crystal structure, transformation temperatures and transformation temperature hysteresis that would significantly affect the shape memory behaviour of the alloy. This paper investigates the effect of ternary alloying of Ti-Pt with varying vanadium contents (0-18.25 at.%) on the as-cast condition. The effect of ternary alloying on the microstructure, transformation temperature and transformation temperature hysteresis were studied. The Ti50-Pt50-x-Vx (x = 6.25 to 18.25 at.%) alloys were produced by the button arc melting method using elemental powders of titanium, platinum and vanadium. Results showed the formation of martensitic a-Ti50(Pt,V)50 with Ti3Pt, (Ti,V)3Pt, Ti4Pt3-like and oxide phases in Ti-Pt-(V) alloys. The phase transformation temperature of Ti-Pt alloys decreased with increasing vanadium content up to 10.2 at.% V.
Effect of powder bed preheating on distortion and mechanical properties in high speed selective laser melting
Authors: Motibane L P , Tshabalala L C , Mathe N R , Hoosain S , Knutsen R D
Published: November 2019

Selective Laser Melting (SLM) is known to cause residual stresses due to the inherent large thermal gradients from high heating and cooling rates during manufacturing. The residual stresses tend to induce distortion, delamination of parts from the base plate as well as cracking because they reduce the threshold flaw size required for crack initiation. These challenges form a barrier to the use of this additive manufacturing method for structural applications for the aerospace industry where high part integrity is a critical requirement. The aim of the study was to evaluate the degree of distortion and crack growth resistance during increasing monotonic loading and cyclic loading of As-built Ti6Al4V parts produced on the Aeroswift high speed SLM process preheated at 200°C. The monotonic loading results are comparable to those of commercial SLM systems but are lower when compared conventional manufacturing methods. The crack growth resistance of the As-built specimen is lower than that of heat treated specimen. Distortion at this preheating temperature is evident at from 12cm away from the base of the cantilever and spreads to height of 3.2mm.
Influence of stress relieving thermal cycles on AISI10Mg specimens produced by selective laser melting
Authors: Mfusi B J , Mathe N R , Popoola P A I , Tshabalala L C
Published: November 2019

The AlSi10Mg alloy is known for its castability, corrosion resistance, high heat conductivity, low weight and good weldability. Applications of the aluminium alloy components includes heat exchangers that are subjected to high temperatures and corrosive environments. The production process of AlSi10Mg alloy using selective laser melting has been extensively explored because of its hypoeutectic composition of Al and Si. However, it has been observed that stress relieve has a negative consequence on tensile properties of SLM built samples, while retaining and improving ductility. The thermal behaviour of AlSi10Mg alloy fabricated by selective laser melting with the specimen heat treated at 300°C for 2 hours investigated in this work. The specimens exhibited mass gain during the thermalgravimetric analysis as a result of the precence of oxygen as one of the elements present as detected by the elemental analysis. The fatigue results post thermal treatment demonstrated improved fatigue resistance qualities comparable to die-casted AlSi10Mg.
Study of the relationship between stacking fault energy and microstructure in different compositions of Fe-Mn steels produced by weld deposit
Authors: Ribamar G G , Andrade T C , Miranda H C , Abreu H F G
Published: November 2019

The properties of high manganese steels are usually related to the mechanism of austenite deformation, either martensite or twin formation during deformation. This deformation mechanism is often related to the stacking fault energy (SFE) that the material possesses. Studies show that SFE values between 0 and 8 mJ/m2; provide formation of ε martensite during deformation, whereas only twins are formed for energies above 18 mJ/m2. Intermediate values provide the formation of both ε martensite and twins. In this way, it is possible to predict the microstructure and, consequently, mechanical properties with the knowledge of the material’s SFE. In this work, a weld consumable with high manganese content was deposited on a SAE 1012 carbon steel plate with the flux-cored arc welding process producing different chemical compositions and consequently different SFE that varied as a function of the dilution. Low dilution conditions led to austenite and ε martensite formation in the molten zone, while in high dilution conditions, α’ martensite were found, besides those other two. Manganese was found to be the most influential element in the phase formation change, based on SFE and SFE components analysis.
Measuring the dislocation density of VT1-0 titanium alloys with different content of hydrogen by x-ray diffraction method
Authors: Xu S P , Kudiiarov V N , Li K , Larionov V V
Published: November 2019

In this study, the distributions of dislocation density with hydrogen concentration in titanium VT1-0 were obtained. The samples with different hydrogen concentrations was carried out by using the Sieverts method. The dislocation densities were obtained by using the full width at height medium calculations from the XRD results of Gaussian approximation fitting. For accurate calculation of the dislocation density in titanium alloys, the double-line separation phenomenon of the XRD results and the variation of the Burgers vector in different lattice directions were considered. The phenomenon of the double-line separation is more evident when the diffraction angle 2θ is larger than 40°. The mean value of dislocation density for the different hydrogen concentrations is about 1013 ∼ 1014 m−2. Moreover, as the increases of hydrogen content in the titanium alloy, the dislocation density also increases.
Mechano-chemical synthesis of crystalline superionic conductors CsAg4Br3-xI2+x (0<x<1) and their silver-conducting properties
Authors: Zuo W B , Pelenovich V O , Tolstogouzov A B , Fu D J
Published: November 2019

Silver ion conductive materials attract numerous interest of research nowadays, due to their high potentiality in the solid electrolyte ion source (SEIS) intended for the application in the ionic thruster. In the work, mechano-chemical synthesis of crystalline superionic conductors CsAg4Br3-xI2+x (0<x<1) was performed by means of high-energy ball milling for the first time. The structure, morphology, and elemental composition were investigated and the effects of iodine content on these properties were studied. Silver-conducting properties were characterized based on the generation of Ag+ ion beams. The ion current of about 15 nA was obtained at 152°C and 15 kV.
Federalism in Rights Cases
Authors: Martenet Vincent
Published: November 2019

This Article examines whether and how, in a federal state, the federated entities’ constitutions, laws, case law, and practices may impact federal fundamental rights cases. Such bottom-up influence may occur in particular when (i) the federated entities have jurisdiction over the relevant area of law and enjoy broad autonomy; (ii) the question raised is controversial, relates to conflicting values, and is linked to the diversity which the constitution protects; (iii) the applicable federal fundamental right is “unenumerated” or not clearly grounded in the constitution; and (iv) the scope of this right is vague. In this respect, federated entities in a federal state may become “constitutional indicators” or even “trailblazers.” They indeed have the potential to indicate a future federal path when, for constitutional reasons, many of them have made similar decisions or choices, or when one or a few pioneering entities wander through unexplored constitutional fields.
Nondeterminacy, cycles and rational choice
Authors: Herlitz Anders
Published: November 2019

A notorious problem that has recently received increased attention in axiology, normative theory and population ethics is the apparent ubiquity of what can be generally called nondeterminacy. This paper illustrates how nondeterminacy can spawn cyclical rankings. So, accepting that practical reasons can admit of nondeterminacy challenges the widely held idea that ‘better than’ is transitive. As a result, standard approaches to rational choice under nondeterminacy fail to be action-guiding, since in some situations all options are dominated, that is, impermissible according to standard rational choice criteria.
Institutional Barriers to Healthy Workplace Environments: From the Voices of Social Workers Experiencing Compassion Fatigue
Authors: Kreitzer Linda , Brintnell Sharon E , Austin Wendy
Published: November 2019

The good health and well-being of health care professionals is increasingly an important issue and one that is under threat due to dominant neo-liberal economic factors. These factors influence health care service delivery which in turn focuses less on employee workplace satisfaction and more on profit-making corporate business models. More work with less pay/benefits, less time to work with clients and the focus on outcomes has created workplaces in which employees are experiencing negative organisational cultures that, in turn, affects their health and well-being. One negative effect is compassion fatigue (CF). In Canada, a national inter-disciplinary research project was conducted for health professionals (n = 52) who self-identified as experiencing CF. From this research, an analysis of a sub-sample of the data of fourteen social workers was conducted identifying specific institutional factors that participants described as creating conditions for their CF. These factors are presented including: (i) cost-effective services within time constraints and political climates; (ii) erosion of relationship building; (iii) lack of communication between managers and front line workers; (iv) cutbacks in services; (v) climate of fear; and (vi) outcome measurement requirements. These concerns related to workplace environments and the health and well-being of health professionals are discussed.
The misdirection of bankers’ moral compass in the organizational field of banking
Authors: van Staveren Irene
Published: November 2019

This article presents the results of a survey on banking culture in the Netherlands. It shows that despite behavioural regulation by the state, bankers continue to be driven by the underlying rationalization in the banking field which is characterized by utility maximization. Moreover, the downsizing of the sector has turned the incentives of targets from positive to negative, while distrust and lack of moral leadership further constrain bankers’ use of their moral compass. An increase in state regulation leads to extensive compliance procedures but does not act as a support for ethical guidance in addressing client interests in a complex and uncertain environment. Bankers feel squeezed between increased legal constraints and ever more detailed rationalization in the banking field, which reduces the space to use their moral compass. This study argues that a change in banking culture should therefore address the field’s rationalization itself, rather than adding more behavioural regulation.
Practical Key-Recovery Attacks On Round-Reduced Ketje Jr, Xoodoo-AE And Xoodyak
Authors: Zhou Haibo , Li Zheng , Dong Xiaoyang , Jia Keting , Meier Willi
Published: November 2019

A new conditional cube attack was proposed by Li et al. at ToSC 2019 for cryptanalysis of Keccak keyed modes. In this paper, we find a new property of Li et al.’s method. The conditional cube attack is modified and applied to cryptanalysis of 5-round Ketje Jr, 6-round Xoodoo-AE and Xoodyak, where Ketje Jr is among the third round CAESAR competition candidates and Xoodyak is a Round 2 submission of the ongoing NIST lightweight cryptography project. For the updated conditional cube attack, all our results are shown to be of practical time complexity with negligible memory cost, and test codes are provided. Notably, our results on Xoodyak represent the first third-party cryptanalysis for Xoodyak.
Optimal data collection for randomized control trials
Authors: Carneiro Pedro , Lee Sokbae , Wilhelm Daniel
Published: November 2019

In a randomized control trial, the precision of an average treatment effect estimator and the power of the corresponding t-test can be improved either by collecting data on additional individuals, or by collecting additional covariates that predict the outcome variable. To design the experiment, a researcher needs to solve this trade-off subject to her budget constraint. We show that this optimization problem is equivalent to optimally predicting outcomes by the covariates, which in turn can be solved using existing machine learning techniques using pre-experimental data such as other similar studies, a census, or a household survey. In two empirical applications, we show that our procedure can lead to reductions of up to 58% in the costs of data collection, or improvements of the same magnitude in the precision of the treatment effect estimator.
LONG-TERM GAIT SPEED TELEMONITORING IN OLDER ADULTS WITH MILD COGNITIVE IMPAIRMENT OR MILD DEMENTIA. THE DECI STUDY
Authors: Donini Lorenzo M , Rainoldi Alberto , Feletti Luca C , Zia Gianluca , Poggiogalle Eleonora , Signore Susanna Del ,   Monika Jurkeviciute on behalf of DECI Consortium
Published: November 2019

Non-intrusive telemonitoring of physical activity in Older Adults suffering from Mild Cognitive Impairment (MCI), or Mild Dementia (MD), was implemented as part of a 6-month multicomponent digital intervention in the DECI study (EU Horizon2020 grant No 643588). Methods: To estimate gait speed long-term trajectory, a processing algorithm was applied on individual accelerometry data continuously recorded via the ADAMO wrist-watch accelerometer. Speed Trend Analysis was performed if patients wore the device ≥90 days. Only outdoor activity was analyzed to reflect patients’ own natural gait speed. Only time spent in high or very-high-activity level is used, to eliminate rest periods (e.g. sitting on a bench, on a bus or driving). A raw mean walking speed was computed. Stride was computed from gender and height and walked distance from stride and step count. Mean walking speed was estimated by walking distance and duration. A rolling mean algorithm was applied to the computed mean 15-day baseline series, resulting in a new series representing normalized patient’s gait speed trajectory during the study. Results: Baseline characteristics: F/M=21/19; MCI/MD=36/4; age=75.4±6.0 years; BMI= 24.6±5,2; MMSE=26.5±2.4; education=8.9±4.0 years. Monitoring days=147±29. Overall three main patterns of gait speed trajectory were identified: “relative stability”, “improving trend” and “progressive decline”: No evident correlation with cognitive status was observed in the sample. Examples of individual patterns are shown. Conclusions: Gait Speed Analysis can describe physical function trajectory over time and identify decliners from stable or improving older adults. Further analyses may clarify the relationship between physical function changes and cognitive status.
A Smartphone Application for Burn Self-care
Authors: Asghari Amrei Shabnam , Ayatollahi Haleh , Salehi Seyed Hamid
Published: November 2019

Burn treatment and management is largely patient-dependent and self-care education helps reducing tangible and intangible costs as well as improving quality of care. Thus, this study aimed to develop a smartphone application for burn self-care. This research, conducted in 2018, consisted of two phases. Initially, the educational content required for the application was determined based on the literature review and clinicians’ and patients’ perspectives. The setting of the study was the largest burn and plastic surgery hospital in the country. Based on the results derived from the first phase of the study, the application prototype was designed in the Persian language to be used on smartphones. The usability of the application was evaluated by using a standard questionnaire and the data were analyzed by using descriptive statistics. The educational content of the application included eight different areas of self-care; namely, wound care, scar management, care and control of hypertrophic burn scars, nutrition, in-home pain management, mental health, follow-up, and rehabilitation. A specialist was consulted and related texts and images were selected to be included in the application. The application was used by burn patients for a week and users evaluated its usability at a good level. It seems that the application designed in the present study can help to increase patients’ knowledge about burn conditions and improve their self-care skills. Further studies are needed to present the efficiency and effectiveness of the application in practice.
Communicating Cosmopolitanism During Times of Crisis: UNHCR and the World Refugee Day Campaign in the UK and Bulgaria
Authors: Balabanova Ekaterina
Published: November 2019

How can a cosmopolitan message about refugees be communicated in an international political context characterized by growing hostility to outsiders at the national level? This article provides a detailed analysis of a specific World Refugee Day campaign based on extensive access to internal data from the UN Refugee Agency (UNHCR) and interviews with key informants alongside case studies of the campaign in two European countries: the United Kingdom (UK) and Bulgaria. While internal UNHCR assessment suggested successful meeting of pre-set targets, a series of issues around the implementation of message framing and the potential for this to generate action are identified. The article applies ideas about the communication of distant suffering to explore how World Refugee Day campaigns operate as interventions into global public discourse. The analysis of the campaign framing finds that it maximized space for solidaristic understanding of the refugee issue and reflexivity. However, the article argues that the communication of these ideas is impacted by the practical and organizational challenges (and opportunities) of developing a professional communication strategy in the context of a rapidly changing media and political environment.
Transhumanism, Moral Perfection, and Those 76 Trombones
Authors: Koch Tom
Published: November 2019

Transhumanism advances an ideology promising a positive human advance through the application of new and as yet unrealized technologies. Underlying the whole is a libertarian ethos married to a very Christian eschatology promising a miraculous transformation that will answer human needs and redress human failings. In this paper, the supposedly scientific basis on which transhumanist promises are built is critiqued as futurist imaginings with little likelihood of actualization. Transhumanists themselves are likened to the affable con man Professor Harold Hill who, in The Music Man, describes as dire social problems whose solution is a youth band he seeks to sell but has no intention of building. Even were some of the transhumanist imaginings to be realized, I argue, the result would be a dystopia in which the few received benefits denied to the many. In advancing imaginary technologies as a solution to human needs, transhumanists and their bioethical fellow travelers handily avoid discussion of or advocacy for the kind of pedestrian social actions that demonstrably could achieve many of their purported goals. So their enthusiasms, I conclude, are not merely fanciful but damaging to the humanist goals they pretend to advance.
Germline Testing for Patients With BRCA1/2 Mutations on Somatic Tumor Testing
Authors: Vlessis Katherine , Purington Natasha , Chun Nicolette , Haraldsdottir Sigurdis , Ford James M
Published: November 2019

Background

The National Comprehensive Cancer Network (NCCN) recommends germline testing for pathogenic BRCA1/2 mutations identified by somatic tumor sequencing. The aim of this study was to explore whether patients at Stanford with somatic BRCA1/2 mutations were recommended germline testing in accordance with NCCN guidelines.

Methods

We retrospectively collected all Stanford patients with BRCA1/2 mutations found by tumor sequencing. Medical records were reviewed for each patient to identify those recommended germline testing. A multivariable logistic regression model was fit associating baseline characteristics with whether or not a recommendation was made.

Results

Of 164 participants, 51 (31.1%) had no recommendation for germline testing. Of the 97 available germline-testing results, 54 (55.7%) were positive for pathogenic BRCA1/2 mutations. After adjusting for possible confounders, patients with genitourinary cancer (odds ratio [OR] = 0.03, 95% confidence interval [CI] = 0.00 to 0.03; P = .003), lung cancer (OR = 0.04, 95% CI = 0.01 to 0.21; P < .001), sarcoma (OR = 0.02, 95% CI = 0.00 to 0.14; P < .001), skin cancer (OR = 0.01, 95% CI = 0.98 to 1.03; P = .002), or “other” diagnoses (OR = 0.01, 95% CI = 0.00 to 0.16; P < .001) were statistically significantly less likely to be recommended germline testing compared with patients with breast or gynecological cancers.

Conclusions

Our study highlights the importance of provider education outside of the oncologic specialties typically associated with BRCA-related cancers and continued exploration of referrals to genetics for germline testing on the basis of somatic findings.
Ancient DNA Reconstructs the Genetic Legacies of Precontact Puerto Rico Communities
Authors: Nieves-Colón Maria A , Pestle William J , Reynolds Austin W , Llamas Bastien , de la Fuente Constanza , Fowler Kathleen , Skerry Katherine M , Crespo-Torres Edwin , Bustamante Carlos D , Stone Anne C
Published: November 2019

Indigenous peoples have occupied the island of Puerto Rico since at least 3000 BC. Due to the demographic shifts that occurred after European contact, the origin(s) of these ancient populations, and their genetic relationship to present-day islanders, are unclear. We use ancient DNA to characterize the population history and genetic legacies of precontact Indigenous communities from Puerto Rico. Bone, tooth, and dental calculus samples were collected from 124 individuals from three precontact archaeological sites: Tibes, Punta Candelero, and Paso del Indio. Despite poor DNA preservation, we used target enrichment and high-throughput sequencing to obtain complete mitochondrial genomes (mtDNA) from 45 individuals and autosomal genotypes from two individuals. We found a high proportion of Native American mtDNA haplogroups A2 and C1 in the precontact Puerto Rico sample (40% and 44%, respectively). This distribution, as well as the haplotypes represented, supports a primarily Amazonian South American origin for these populations and mirrors the Native American mtDNA diversity patterns found in present-day islanders. Three mtDNA haplotypes from precontact Puerto Rico persist among Puerto Ricans and other Caribbean islanders, indicating that present-day populations are reservoirs of precontact mtDNA diversity. Lastly, we find similarity in autosomal ancestry patterns between precontact individuals from Puerto Rico and the Bahamas, suggesting a shared component of Indigenous Caribbean ancestry with close affinity to South American populations. Our findings contribute to a more complete reconstruction of precontact Caribbean population history and explore the role of Indigenous peoples in shaping the biocultural diversity of present-day Puerto Ricans and other Caribbean islanders.
Developmental Systems Drift and the Drivers of Sex Chromosome Evolution
Authors: Cauret Caroline M S , Gansauge Marie-Theres , Tupper Andrew S , Furman Benjamin L S , Knytl Martin , Song Xue-Ying , Greenbaum Eli , Meyer Matthias , Evans Ben J
Published: November 2019

Phenotypic invariance—the outcome of purifying selection—is a hallmark of biological importance. However, invariant phenotypes might be controlled by diverged genetic systems in different species. Here, we explore how an important and invariant phenotype—the development of sexually differentiated individuals—is controlled in over two dozen species in the frog family Pipidae. We uncovered evidence in different species for 1) an ancestral W chromosome that is not found in many females and is found in some males, 2) independent losses and 3) autosomal segregation of this W chromosome, 4) changes in male versus female heterogamy, and 5) substantial variation among species in recombination suppression on sex chromosomes. We further provide evidence of, and evolutionary context for, the origins of at least seven distinct systems for regulating sex determination among three closely related genera. These systems are distinct in their genomic locations, evolutionary origins, and/or male versus female heterogamy. Our findings demonstrate that the developmental control of sexual differentiation changed via loss, sidelining, and empowerment of a mechanistically influential gene, and offer insights into novel factors that impinge on the diverse evolutionary fates of sex chromosomes.
A DNA G-quadruplex/i-motif hybrid
Authors: Chu Betty , Zhang Daoning , Paukstelis Paul J
Published: November 2019

DNA can form many structures beyond the canonical Watson–Crick double helix. It is now clear that noncanonical structures are present in genomic DNA and have biological functions. G-rich G-quadruplexes and C-rich i-motifs are the most well-characterized noncanonical DNA motifs that have been detected in vivo with either proscribed or postulated biological roles. Because of their independent sequence requirements, these structures have largely been considered distinct types of quadruplexes. Here, we describe the crystal structure of the DNA oligonucleotide, d(CCAGGCTGCAA), that self-associates to form a quadruplex structure containing two central antiparallel G-tetrads and six i-motif C–C+ base pairs. Solution studies suggest a robust structural motif capable of assembling as a tetramer of individual strands or as a dimer when composed of tandem repeats. This hybrid structure highlights the growing structural diversity of DNA and suggests that biological systems may harbor many functionally important non-duplex structures.
Screening, Brief Intervention, and Referral to Treatment for Prenatal Alcohol Use and Cigarette Smoking: A Survey of Academic and Community Health Care Providers
Authors: Ordean Alice , Forte Milena , Selby Peter , Grennell Erin
Published: November 2019

Objectives:

Prenatal alcohol and cigarette smoking are associated with numerous adverse pregnancy outcomes. Screening, Brief Intervention, and Referral to Treatment (SBIRT) represents a standardized approach; however, implementation in routine pregnancy care remains a challenge. The purpose of the study was to determine current practices, barriers to implementation, and education needs of healthcare providers utilizing SBIRT to address prenatal alcohol and cigarette smoking.

Methods:

We conducted a survey of 118 providers including family physicians, midwives, and obstetricians practicing at 2 Toronto hospitals: community-based teaching site and fully affiliated academic health sciences center.

Results:

The response rate was 79%. Almost all providers reported screening every pregnant woman for alcohol and smoking status. Brief intervention was offered by fewer providers. Education and supportive counseling were reported by a higher percentage of providers for prenatal cigarette smoking in comparison to alcohol use. Furthermore, up to 60% referred pregnant women to treatment programs for alcohol and cigarette smoking. A significantly higher number of community-based providers reported referring pregnant women to addiction treatment programs. Barriers to interventions included a perceived lack of appropriate resources, training, and clinical pathways.

Conclusion:

Healthcare providers report universal screening for prenatal alcohol and cigarette smoking; however, brief intervention and referral to treatment are more limited practices. There is a need for education of all providers regarding effective brief counseling strategies and referral to appropriate treatment resources. Development of clinical care pathways may also increase adoption of all components of SBIRT for prenatal alcohol use and cigarette smoking.
Perceived Benefits and Barriers to a Career in Neuroanesthesiology: A Pilot Survey of Anesthesiology Clinicians
Authors: Rajan Shobana , Theard Marie A. , Easdown Jane , Goyal Keshav , Pasternak Jeffrey J.
Published: November 2019

Background:

Despite advances in perioperative neuroscience, there is low interest among anesthesiology trainees to pursue subspecialty training in neuroanesthesiology. We conducted a pilot survey to assess attitudes about neuroanesthesiology fellowship training.

Materials and Methods:

A confidential survey was distributed to an international cohort of anesthesiology attendings and trainees between January 15, 2017 and February 26, 2017.

Results:

A total of 463 responses were received. Overall, 309 (67%), 30 (6%), 116 (25%), and 8 (2%) of respondents identified themselves as attendings, fellows, residents, and “other,” respectively. In total, 390 (84%) of respondents were from the United States. Individuals typically pursue anesthesiology fellowship training because of interest in the subspecialty, acquisition of a special skill set, and the role of fellowship training in career planning and advancement. Overall, 64% of attendings, 56% of fellows, and 55% of residents favored accreditation of neuroanesthesiology fellowships, although opinion was divided regarding the role of accreditation in increasing interest in the specialty. Respondents believe that increased opportunities for research and greater exposure to neurocritical care and neurological monitoring methods would increase interest in neuroanesthesiology fellowship training. Perceived barriers to neuroanesthesiology fellowship training were perceptions that residency provides adequate training in neuroanesthesiology, that a unique skill set is not acquired, and that there are limited job opportunities available to those with neuroanesthesiology fellowship training.

Conclusions:

In this pilot survey, we identified several factors that trainees consider when deciding to undertake subspecialty training and barriers that might limit interest in pursuing neuroanesthesiology subspecialty training. Our findings may be used to guide curricular development and identify factors that might increase interest among trainees in pursuing neuroanesthesiology fellowship training.
Effect of Stimulation Rate on Speech Understanding in Older Cochlear-Implant Users
Authors: Shader Maureen J. , Nguyen Nicole , Cleary Miranda , Hertzano Ronna , Eisenman David J. , Anderson Samira , Gordon-Salant Sandra , Goupell Matthew J.
Published: November 2019

Objectives:

Cochlear implants (CIs) are considered a safe and effective intervention for more severe degrees of hearing loss in adults of all ages. Although older CI users ≥65 years of age can obtain large benefits in speech understanding from a CI, there is a growing body of literature suggesting that older CI users may not perform as well as younger CI users. One reason for this potential age-related limitation could be that default CI stimulation settings are not optimal for older CI users. The goal of this study was to determine whether improvements in speech understanding were possible when CI users were programmed with nondefault stimulation rates and to determine whether lower-than-default stimulation rates improved older CI users’ speech understanding.

Design:

Sentence recognition was measured acutely using different stimulation rates in 37 CI users ranging in age from 22 to 87 years. Maps were created using rates of 500, 720, 900, and 1200 pulses per second (pps) for each subject. An additional map using a rate higher than 1200 pps was also created for individuals who used a higher rate in their clinical processors. Thus, the clinical rate of each subject was also tested, including non-default rates above 1200 pps for Cochlear users and higher rates consistent with the manufacturer defaults for subjects implanted with Advanced Bionics and Med-El devices. Speech understanding performance was evaluated at each stimulation rate using AzBio and Perceptually Robust English Sentence Test Open-set (PRESTO) sentence materials tested in quiet and in noise.

Results:

For Cochlear-brand users, speech understanding performance using non-default rates was slightly poorer when compared with the default rate (900 pps). However, this effect was offset somewhat by age, in which older subjects were able to maintain comparable performance using a 500-pps map compared with the default rate map when listening to the more difficult PRESTO sentence material. Advanced Bionics and Med-El users showed modest improvements in their overall performance using 720 pps compared with the default rate (>1200 pps). On the individual-subject level, 10 subjects (11 ears) showed a significant effect of stimulation rate, with 8 of those ears performing best with a lower-than-default rate.

Conclusions:

Results suggest that default stimulation rates are likely sufficient for many CI users, but some CI users at any age can benefit from a lower-than-default rate. Future work that provides experience with novel rates in everyday life has the potential to identify more individuals whose performance could be improved with changes to stimulation rate.
Effects of Surface Topography and Chemistry on Polyether-Ether-Ketone (PEEK) and Titanium Osseointegration
Authors: Torstrick F. Brennan , Lin Angela S.P. , Safranski David L. , Potter Daniel , Sulchek Todd , Lee Christopher S.D. , Gall Ken , Guldberg Robert E.
Published: November 2019

Study Design.

An in vivo study examining the functional osseointegration of smooth, rough, and porous surface topographies presenting polyether-ether-ketone (PEEK) or titanium surface chemistry.

Objective.

To investigate the effects of surface topography and surface chemistry on implant osseointegration.

Summary of Background Data.

Interbody fusion devices have been used for decades to facilitate fusion across the disc space, yet debate continues over their optimal surface topography and chemistry. Though both factors influence osseointegration, the relative effects of each are not fully understood.

Methods.

Smooth, rough, and porous implants presenting either a PEEK or titanium surface chemistry were implanted into the proximal tibial metaphyses of 36 skeletally mature male Sprague Dawley rats. At 8 weeks, animals were euthanized and bone–implant interfaces were subjected to micro-computed tomography analysis (n = 12), histology (n = 4), and biomechanical pullout testing (n = 8) to assess functional osseointegration and implant fixation.

Results.

Micro-computed tomography analysis demonstrated that bone ingrowth was 38.9 ± 2.8% for porous PEEK and 30.7 ± 3.3% for porous titanium (P = 0.07). No differences in fixation strength were detected between porous PEEK and porous titanium despite titanium surfaces exhibiting an overall increase in bone–implant contact compared with PEEK (P < 0.01). Porous surfaces exhibited increased fixation strength compared with smooth and rough surfaces regardless of surface chemistry (P < 0.05). Across all groups both surface topography and chemistry had a significant overall effect on fixation strength (P < 0.05), but topography accounted for 65.3% of the total variance (ω2 = 0.65), whereas surface chemistry accounted for 5.9% (ω2 = 0.06).

Conclusions.

The effect of surface topography (specifically porosity) dominated the effect of surface chemistry in this study and could lead to further improvements in orthopedic device design. The poor osseointegration of existing smooth PEEK implants may be linked more to their smooth surface topography rather than their material composition.

Level of Evidence: N/A
Self-Experienced Trunk Appearance in Individuals With and Without Idiopathic Scoliosis
Authors: Savvides Panayiotis , Gerdhem Paul , Grauers Anna , Danielsson Aina , Diarbakerli Elias
Published: November 2019

Study Design.

Cross-sectional.

Objective.

The aim of this study was to describe the self-experienced trunk appearance in individuals with and without idiopathic scoliosis.

Summary of Background Data.

Idiopathic scoliosis is the most common spinal deformity. A large scoliotic deformity increases the risk of back pain and pulmonary dysfunction. The deformity has also a psychological impact.

Methods.

The pictorial part of the spinal appearance questionnaire (pSAQ) was administered to 1416 individuals with idiopathic scoliosis (386 untreated, 529 brace treated, 501 surgically treated) and 272 individuals without scoliosis from the general population. Comparisons were made between individuals with and without scoliosis, between treatment groups and sex in the scoliosis group.

Results.

Mean (95% confidence interval) age of the individuals with scoliosis was 36.2 (35.5–36.9) years and for the individuals without scoliosis 40.2 (37.9–42.4). pSAQ total was 12.3 (12.1–12.5) for individuals with scoliosis and 7.4 (7.3–7.6) for individuals without scoliosis (P < 0.001, adjusted for age and sex). pSAQ total was 11.5 (11.1–11.9) for untreated, 13.0 (12.6–13.3) for brace treated, and 12.3 (11.9–12.6) for surgically treated individuals (P < 0.001, adjusted for sex and curve size). The pSAQ total between males and females with idiopathic scoliosis did not differ (P = 0.22 adjusted for age and curve size).

Conclusion.

This study shows that individuals with idiopathic scoliosis have more concern about their body appearance than individuals without scoliosis. Untreated individuals are not as bothered of their spinal appearance as treated individuals. Males and females with scoliosis do not differ significantly in the perception of their spinal appearance.

Level of Evidence: 3
Percutaneous Transforaminal Endoscopic Discectomy Versus Microendoscopic Discectomy for Lumbar Disc Herniation
Authors: Chen Zihao , Zhang Liangming , Dong Jianwen , Xie Peigen , Liu Bin , Wang Qiyou , Chen Ruiqiang , Shu Tao , Li Shangfu , Feng Feng , Yang Bu , He Lei , Yang Yang , Liu Zhongyu , Pang Mao , Rong Limin
Published: November 2019

Study Design.

A prospective randomized controlled study.

Objective.

To clarify whether percutaneous transforaminal endoscopic discectomy (PTED) has better clinical outcomes and less surgical trauma compared with microendoscopic discectomy (MED).

Summary of Background Data.

Two kinds of minimally invasive spine surgeries, PTED and MED, are now widely used for the treatment of lumbar disc herniation (LDH). It is still a controversial issue to choose the proper surgical approach.

Methods.

In this single-center, open-label, randomized controlled trial, patients were included if they had persistent signs and symptoms of radiculopathy with corresponding imaging-confirmed LDH, and were randomly allocated to PTED or MED group. The primary outcome was the score of Oswestry Disability Index (ODI) and the secondary outcomes included the score of Medical Outcomes Study 36-Item Short-Form Health Survey bodily pain and physical function scales, European Quality of Life-5 Dimensions, and Visual Analogue Scales for back pain and leg pain.

Results.

A total of 250 participants were randomly assigned to two treatment groups, 241 of that received the specific surgical procedure. Two hundred twenty-two patients (92.1%) have completed the 2-year follow-up. Both the primary and secondary outcomes did not differ significantly between the two treatment groups at each prespecified follow-up time (P > 0.05). For PTED, the postoperative improvement of ODI score in the median herniation subgroup was less compared with paramedian subgroup. For MED, less improvement of ODI score was found in far-lateral herniation subgroup compared with paramedian subgroup. Total complication rate over the course of 2 year was 13.44% in PTED group and 15.57% in MED group (P = 0.639). Ten cases (8.40%) in PTED group and five cases (4.10%) in MED group suffered from residue/recurrence of herniation, for which reoperation was required.

Conclusion.

Over the 2-year follow-up period, PTED did not show superior clinical outcomes and did not appear to be safer procedure for patients with LDH compared with MED. PTED had inferior results for median disc herniation, whereas MED did not appear to be the best option for far-lateral disc herniation.

Level of Evidence: 2
Rapid disease progression in patient with mismatch-repair deficiency pituitary ACTH-secreting adenoma treated with checkpoint inhibitor pembrolizumab
Authors: Caccese Mario , Barbot Mattia , Ceccato Filippo , Padovan Marta , Gardiman Marina Paola , Fassan Matteo , Denaro Luca , Emanuelli Enzo , D’Avella Domenico , Scaroni Carla , Zagonel Vittorina , Lombardi Giuseppe
Published: November 2019

Secreting pituitary adenomas are tumors for which few treatment options are available, including surgical treatment and management of hormonal imbalance due to altered pituitary secretion. In case of inoperable relapse, radiotherapy or chemotherapeutic treatment can be considered; the effectiveness of these treatments, however, remains limited. In the immunotherapy era, it is necessary to select patients who can benefit from immunotherapeutic treatment. Mismatch repair deficiency is strongly associated with responsiveness to anti-PD-1 in other cancers and can be detected using immunohistochemistry for MLH1, MSH2, MHS6, and PMS2. In this case report, we report a case of rapid disease progression to pembrolizumab in a patient with a MMRd pituitary adrenocorticotropic hormone (ACTH)-secreting adenoma. For the best of our knowledge, we described for the first time, a poor efficacy of pembrolizumab in a patient with ACTH-secreting pituitary adenoma having mismatch repair deficiency probably caused by high levels of cortisol in this patient. Prospective study should be performed to assess the activity of immune checkpoint inhibitor alone or in association with temozolomide in this subsetting of pituitary adenomas.