bluuebunny/crossref_metadata_2025 huggingface dataset:
Functional roles of coral reef primary producers examined with stable isotopes
Authors: Godinez-Espinosa Sara , Raoult Vincent , Smith Timothy M. , Gaston Troy F. , Williamson Jane E.
Published: May 2023

Context Primary production on coral reefs varies under changing conditions such as light and nutrient availability. This variation causes changes in basal stable isotopes as photosynthetic and nutrient pathways change. Aims This study provides a preliminary baseline of nitrogen (δ15N) and carbon (δ13C) stable isotope profiles in Symbiodinium and macroalgae at a spatial scale and along a depth gradient around an island. Methods Coral fragments and macroalgae were collected at depths from the surface to 26 m. δ15N and δ13C stable isotope values were assessed for Symbiodinium relative to cell density per surface area. Key results δ15N values showed a uniform nutrient profile across primary producers. However, chlorophyll-a and Symbiodinium density from Montipora stellata had higher concentrations on the southern side of the island. δ15N values of Symbiodinium from Stylophora pistillata and macroalgae did not change with depth. Depth was associated with a significant decrease in Symbiodinium density, and δ13C values in macroalgae. Conclusions We attribute these findings to Symbiodinium from S. pistillata as depth increases, decreasing cell density but maintaining chlorophyll-a concentration to satisfy the coral-host nutrient requirements. Implications This study sets the scene for future, more comprehensive research on detecting carbon and nitrogen stable isotope values on primary producers in coral reefs.
Dovobet ointment under occlusion overnight for troublesome scalp psoriasis
Authors: Downs AM.
Published: May 2023

This article does not have an abstract.
Pimecrolimus cream 1% is effective in a case of granulomatous rosacea
Authors: Cunha PR , Rossi AB.
Published: May 2023

This article does not have an abstract.
Point mutation in the STS gene in a severely affected patient with X-linked recessive ichthyosis
Authors: Gonzalez-Huerta LM , Messina-Baas OM , Toral-Lopez J , Rivera-Vega MR , Kofman-Alfaro S , Cuevas-Covarrubias SA.
Published: May 2023

This article does not have an abstract.
Effects of V concentration on the physical properties of Cr1−x
Al
x
alloy system
Authors: Muchono B , Sheppard C J , Prinsloo A R E
Published: May 2023

Electrical resistivity (ρ), magnetic susceptibility (χ) and thermoelectric power (S) studies reported previously on the (Cr1-x
Al
x
)99V1 alloy system indicate a suppression of antiferromagnetism in the concentration range 0.015 ≤ x ≤ 0.040. The present study incorporates Sommerfeld electronic specific heat coefficient (γ), thermal conductivity (κ), Hall coefficient (R
H) and analyses of the previous results in order to have a comprehensive study of the alloy system. γ(x) depicts two peaks close to the same concentrations where dS/dT|T→2K(x) have minima, i.e. at x
c1 ≈ 0.015 and x
c2 ≈ 0.040. Such peaks and minima, respectively, have been considered as key signatures of quantum criticality (QC) in alloys of Cr. Evidence of band structure modification in the alloy system is shown by a change of slope in the Nordheim-Gorter (N-G) relationship showing a minimum at an extrapolated concentration x = 0.035. The slope is positive for the incommensurate (I) spin-density-wave (SDW) alloys with x < 0.035 and a negative for the commensurate (C) SDW alloys with x > 0.035. A behaviour reminiscent of changes in the band structure is also observed in the Lorenz number, L(x), for the alloy with x = 0. R
H(T) results in the range 0 ≤ x ≤ 0.026 have a sharp increase in the charge carrier density, n
2K = [qR
H(2k)]−1, at the ISDW to paramagnetic (P) phase transition. The concentrations x = 0.015 and x = 0.040 are therefore considered ISDW to P and P to CSDW quantum critical points, respectively.
Effect of structure parameters on electron mobility in asymmetric V-shaped double quantum well structure
Authors: Jena Devika , Sahu Ajit Kumar , Sahoo Narayan , Tripathy Aruna , Panda Ajit K , Sahu Trinath
Published: May 2023

Here, we analyse the effect of structure parameters like well width (w), central barrier width (b), and alloy concentration (x) on multisubband electron mobility μ in a GaAs-AlxGa1-xAs based modulation doped asymmetric V-shaped-double-quantum-well (VDQW) structure. The asymmetry in the structure potential is generated through the difference in the doping concentrations (N

d
) in the side barriers i.e., N

d1 (0 to 4 × 1018 cm−3) and N

d2 (2 × 1018 cm−3). The mobility μ is calculated by considering ionised impurity (imp) and alloy disorder (ad) scattering mechanisms. The continuous variation of x inside the well makes μ

ad
< μ

imp
resulting in the dominance of ad-scattering on μ as a function of N

d1. As a result, at the interface an increase in x from 0.1 to 0.3 reduces μ around 40%. However, an increase in w symmetrically (w
1 = w
2) enhances μ. Further, the introduction of non-symmetric well profile (w
1 ≠ w
2) not only causes asymmetric redistribution of subband wave functions ψ
0 and ψ
1 in the wells, but also changes the position and hence occupation of subband energy levels, thereby influencing the subband mobility. As the difference in w
1 and w
2 increases, the system becomes more and more single subband occupied as a function of N

d1 and hence the mobility enhances due to the absence of intersubband scattering. Our results also reflected that an increase in b from 20 Å to 80 Å has a marginal effect on μ during single subband occupancy but improves μ during double subband occupancy through intersubband interaction.
Effective crack-prevention strategy with composite of two clays of different sized particles
Authors: Ghosh Ankita , Majumdar Sudeshna , Tarafdar Sujata , Kumar Ghosh Anup , Dutta Tapati
Published: May 2023

Crack formation and its possible prevention or remedy is an important branch of material science, closely related to study of granular materials and soft matter physics. This work reports a study on cracking behaviour in composites of bentonite and Laponite® in varying proportions. Both components are clays of the montmorillonite group. Our experiments demonstrate that for the particular composition - Laponite® : bentonite ∼1:1, cracks are totally absent. If either component exceeds the other, cracks develop. This is demonstrated over a range of film thickness. Scanning Electron Microscope (SEM) images of the films at different compositions indicate that at this particular ratio, the much smaller particles of Laponite®, pack into the spaces between the bentonite platelets perfectly, to form a defect-free smooth film.
Conceptual Polarization Setup at CENTAUR, the SANS/WANS Instrument at the Second Target Station of SNS
Authors: Qian Shuo , Jiang Chenyang , Li Fankang , Khaplanov Anton
Published: May 2023

CENTAUR is a multifunctional general purpose small-angle and wide-angle neutron scattering instrument with diffraction and spectroscopic capability in the future Second Target Station at the Spallation Neutron Source of the Oak Ridge National Laboratory. To fill a gap in neutron polarization capability, the instrument will be designed to provide polarization analysis. Here we present the conceptual polarization setup at CENTAUR, as well as the Spin Echo Modulated Small-Angle Neutron Scattering setup which will further expand the length scale covered by the instrument.
The first polarized neutron diffraction experiment at the time-of-flight single crystal neutron diffractometer SENJU at J-PARC
Authors: Takahashi S , Kiyanagi R , Kobayashi R , Okudaira T , Ino T , Suzuki J , Kakurai K , Oku T
Published: May 2023

The 3He spin filter has been developed to use pulsed neutrons effectively at J-PARC MLF. In this study, the 3He spin filter was installed in the single crystal neutron diffractometer (BL18 SENJU) at J-PARC MLF as a polarizer of the incident beam, and Half-polarized neutron diffraction experiments were performed. The 3He spin filter was used the ”drop-in cell” method with cells that had a relaxation time of 150 hours in the past experiments. The sample was a single crystal of Heusler crystal Cu2MnAl and the sample magnetic field was 0.3 T. The intensities of (111) Bragg peaks of Cu2MnAl were drastically changed with the polarity of the incident neutron beam, and the flipping ratio of 21.7 at 3.6 Å was observed. The experimental setup and the performance of the 3He spin filter used in this experiment are described in detail in this paper.
Advanced polarization analysis capability on the very small-angle neutron scattering instrument at the NIST Center for Neutron Research
Authors: Chen W.C. , Krycka K.L. , Watson S.M. , Barker J.G. , Gaudet J. , Burrall H. , Borchers J.A.
Published: May 2023

The Very Small Angle Neutron Scattering (VSANS) diffractometer at the National Institute of Standards and Technology has been commissioned and is in the user program. A large available space of nearly 2 m along the beam in the sample area not only enhances the existing SANS polarization analysis capability, but also makes it possible for implementation of other polarization analysis capabilities which would not be easily available on existing SANS instruments, including grazing-incidence small-angle neutron scattering with polarization analysis and spherical neutron polarimetry. We present two polarized setups, one for high magnetic sample fields and the other for low magnetic sample fields, together with a versatile and flexible operational platform for polarized beam experiments. The design of a magnetostatic cavity device that provides better field homogeneity and thus longer 3He polarization relaxation time is discussed. It consists of an end-compensated magnetic shielded solenoid with non-identical holes to accommodate the divergent scattered beam in a constrained distance. Significant improvement in polarized neutronic performance, 3He polarization relaxation time, and an extended momentum transfer range for polarization analysis are presented. Improved neutron polarizing devices, double V-shaped supermirror polarizer, adiabatic radio-frequency spin flipper, and a 3He spin analyzer have yielded an initial instrumental flipping ratio of 100, allowing for higher sensitivity to detection of weak magnetic features in the sample.
Simulations and concepts for a 2-D spin-echo modulated SANS (SEMSANS) instrument
Authors: Parnell Steven R. , Berg Sergi Van Den , Bolderink Gregor , Bouwman Wim G.
Published: May 2023

The spin-echo small-angle neutron scattering (SESANS) technique utilises a series of inclined magnetic fields before and after the sample to encode the scattering angle into the polarisation to obtain a much higher resolution than in conventional SANS. The analogous technique (spin echo modulated SANS (SEMSANS)) implements spin manipulations before the sample only to encode the scattering into an intensity modulation. The technique can be combined with SANS to expand the length scale range probed from 1 nm to microns.

Using McStas we show that using a series of four magnetic Wollaston prisms in two orthogonal pairs with a 90° rotation can be utilised to create SEMSANS modulations in 2-D. These modulations can also be of different periods in each encoding direction. This method can be applied to anisotropic scattering samples. Also this allows for the simultaneous measurement at two orthogonal independent spin-echo lengths. This technique yields directly information about the structure of oriented structures.
Current policies are insufficient to protect or restore Brazil’s cost-effective conservation priority zones
Authors: Ramos Rafael G , Scarabello Marluce , Soterroni Aline C , Andrade Pedro R , Simões Rolf , Ruivo Heloisa M , Kraxner Florian , Ramos Fernando M
Published: May 2023

In Brazil, conservation priority zones, in spite of their key role in preserving natural vegetation and its environmental resources are frequently located outside the country’s public network of protected areas (PAs). Here we present the first study on land-use impacts inside Brazil’s unprotected (i.e. outside PAs) Cost-Effective conservation priority Zones (CEZs), for the period 2020–2050. CEZs are conservation priority zones that had experienced low levels of human impact in 2020. In this study, we consider various governance scenarios, including different deforestation control and native vegetation restoration policies. To this end, a land-use change model is combined with a downscaling method to generate natural vegetation cover projections at a 0.01

∘

resolution. Results, which include the effects of climate change on the expansion of the Brazilian agriculture, project native vegetation losses (through deforestation) or gains (through restoration) inside unprotected CEZs. If the current pattern of disregard for the environment persists, our results indicate that a large share of the native vegetation inside Brazil’s CEZs is likely to disappear, with negative impacts on biodiversity preservation, green-house gas emissions and ecosystem services in general. Moreover, even if fully implemented and enforced, Brazil’s current Forest Code is insufficient to adequately protect CEZs from anthropization, especially in the Cerrado biome. We expect that this study can help improving the conservation and restoration of CEZs in Brazil.
A Study on Effectiveness of Ecolabels in the Fast-Moving Consumer Goods Sector
Authors: Paul Dipen , Malik Sushant , Mishra Dharmesh K. , Teotia Amit
Published: May 2023

Ecolabels are not enough to solve sustainable consumption and procurement; if the awareness of ecolabels among the population is increased, a significant amount of purchase behavior can be changed towards eco-labeled products. Food consumption or fast-moving consumer goods is one such sector that can be looked upon to bring out changes in the food consumption habits of people. Programs to impart ecolabel knowledge can be implemented to increase the perception of individual towards saving the environment and thereby increasing the perceived environmental attitude. For the analysis, the sample size of 206 individuals was tested for the various hypotheses. 45% of the respondents have significant awareness of ecolabels and the steps can be taken to design the ecolabels for food products consumed daily. The results suggest that attention to ecolabels can be a significant factor in increasing ecolabels’ awareness. With the increase in awareness the buying or purchase intention of eco-labeled products also increases. Understanding the effectiveness of ecolabelling will help in developing the comprehensive ecolabelling scheme for food products and consumer good which may result in emission reduction since ecolabels considers the life cycle assessment and the impact of product on environment.
First and second law analysis of dedicated hydrogen fuelled PFI-DTSI (Port Fuel Injection-Digital Three) high-speed SI engine
Authors: Jalindar Shinde Balu , Karunamurthy K
Published: May 2023

The first and second law analysis was performed on a Single Cylinder, Multivalve, Electronic Fuel Injection, and high-speed motor fuelled engine with Gasoline and Hydrogen to assess energetic and exegetic performance. The engine was evaluated from 3000 rpm to 6000 rpm with both fuels. All tests are conducted at Wide Open Throttle conditions. The gasoline combustion was at stoichiometric, and hydrogen was lean burn. The most extreme energy and exergy efficiency was observed with hydrogen at 39.06% and 36.58% separately. Gasoline fuel 36.8 % and 34.6 % energy and exergy recorded at the same speed of 6000 rpm. The highest performance of hydrogen is due to high flame speed, and higher flame temperature. This shows that hydrogen converts the most extreme chemical energy to yield more power than gasoline. The coolant energy and exergy are additionally higher with hydrogen fuel. The lowest coolant energy is gasoline. The outcomes are additionally checked with combustion investigation of each fuel and found heat release rate was most extreme with hydrogen, trailed by gasoline. The greatest exergy destruction of 48.57 kW was with gasoline and followed by minimal with hydrogen. The greatest entropy is 49.45 W/K for gasoline and 22.22 W/K for hydrogenengines individually.
Computational Heat transfer analysis of capsulated liquid metal fins
Authors: Geethika B , Revanth Venkat A , Durgesh K , Venkatesan M
Published: May 2023

Fins are extended surfaces to increase convection heat transfer. Conventional fins are made of solid metals and alloys. Liquid metals such as sodium have melting points below atmospheric temperature. Liquid metals have lower specific heats and higher thermal diffusivity when compared to solid metals. These properties can be used in enhancing heat transfer. In the present work, a numerical model is developed for analyzing the effect of capsulating liquid metal in a solid pin fin. COMSOL Multiphysics package is used to determine heat transfer characteristics under varying geometric and flow conditions. The enhancement of heat transfer due to capsulating Mercury in the Aluminium pin fin when compared to solid Aluminium pin fin is detailed.
The Quest for Quality Healthcare Services  What we can learn from a settlement-based case study?
Authors: Roy Sarani , Rai Anu
Published: May 2023

Adopting the case study approach present study attempts to unwrap the status of the healthcare accessibility of the Berhampur Community Development (CD) block of Murshidabad. A network-based method integrated with the gravity model is used to identify under-serviced areas that do not have access to essential healthcare services at the settlement level. The attempt is made to map the significant socio-economic and demographic factors affecting the accessibility of quality healthcare services that can suggest the best possible solution to considering the heterogeneous needs of the population concerning healthcare services. The healthcare accessibility index (Ai) to the population demand is mapped to delineate the underserviced area. The Joint Hansen’s Improved Gravity Model and Huff Model (probability model) is used with deprivation mapping. Following the human- rights approach of the good living standards, fourteen indicators were extracted from census data, and the indicators were standardized by applying a min-max normalization formula. The indices calculate to measure healthcare deprivation, and inaccessibility at the neighborhood scale indicate the sharp differences in the spatial context. The increasing coverage of healthcare facilities has yet to address the issue of accessibility as an interplay between facilities-connectivity matrix. The study used a connectivity matrix to analyze healthcare accessibility and found that network-based measurement of health accessibility is more suitable over straight-line distance. We found this work may help support policymaking and bridge the gap between the biased share of infrastructure coverage and health care disparity in the study area.
Surface modification of PVA/Chitosan/PEG/HAp nanofiber scaffolds by plasma treatment and studies of their morphology, wettability, and biodegradation rate
Authors: Hartatiek  , Wuriantika M I , Amalia S , Masruroh  , Yudyanto  , Nurhuda M , Santjojo D J D H
Published: May 2023

Nanofiber scaffold has been widely developed as a tissue engineering material because it can imitate the ECM of bones. In this study, nanofiber scaffold is composed of polyvinyl alcohol (PVA), chitosan, polyethylene glycol (PEG), and hydroxyapatite (HAp) which have superior characteristics for tissue engineering applications. The nanofiber scaffold is synthesized using electrospinning. Experimental results show that dielectric barrier discharge (DBD) plasma treatment causes increased surface roughness, contributing to the improvement of surface wettability. This is indicated by a decrease in this contact angle from 9.92° to 1.74°. In addition, DBD plasma treatment also increased biodegradation as well as increased treatment time.
A high-level quantum chemical study of the thermodynamics associated with chlorine transfer between N-chlorinated nucleobases
Authors: O’Reilly Robert J , Karton Amir
Published: May 2023

The relative free energies of the isomers formed upon N-chlorination of each nitrogen atom within the DNA nucleobases (adenine, guanine, and thymine) have been obtained using the high-level G4(MP2) composite ab initio method (the free energies of the N-chlorinated isomers of cytosine have been reported at the same level of theory previously). Having identified the lowest energy N-chlorinated derivatives for each nucleobase, we have computed the free energies associated with chlorine transfer from N-chlorinated nucleobases to other unsubstituted bases. Our results provide quantitative support pertaining to the results of previous experimental studies, which demonstrated that rapid chlorine transfer occurs from N-chlorothymidine to cytidine or adenosine. The results of our calculations in the gas-phase reveal that chlorine transfer from N-chlorothymine to either cytosine, adenine, or guanine proceed via exergonic processes with ΔG
o values of −50.3 (cytosine), −28.0 (guanine), and −6.7 (adenine) kJ mol–1. Additionally, we consider the effect of aqueous solvation by augmenting our gas-phase G4(MP2) energies with solvation corrections obtained using the conductor-like polarizable continuum model. In aqueous solution, we obtain the following G4(MP2) free energies associated with chlorine transfer from N-chlorothymine to the three other nucleobases: −58.4 (cytosine), −26.4 (adenine), and −18.7 (guanine) kJ mol–1. Therefore, our calculations, whether in the gas phase or in aqueous solution, clearly indicate that chlorine transfer from any of the N-chlorinated nucleobases to cytosine provides a thermodynamic sink for the active chlorine. This thermodynamic preference for chlorine transfer to cytidine may be particularly deleterious since previous experimental studies have shown that nitrogen-centered radical formation (via N–Cl bond homolysis) is more easily achieved in N-chlorinated cytidine than in other N-chlorinated nucleosides.
The Kac formula and Poincaré recurrence theorem in Riesz spaces
Authors: Azouzi Youssef , Ben Amor Mohamed , Homann Jonathan , Masmoudi Marwa , Watson Bruce
Published: May 2023

Riesz space (non-pointwise) generalizations for iterative processes are given for the concepts of recurrence, first recurrence and conditional ergodicity. Riesz space conditional versions of the Poincaré Recurrence Theorem and the Kac formula are developed. Under mild assumptions, it is shown that every conditional expectation preserving process is conditionally ergodic with respect to the conditional expectation generated by the Cesàro mean associated with the iterates of the process. Applied to processes in

L
1

(
Ω
,

A

,
μ
)

L^1(\Omega ,{\mathcal A},\mu )

, where

μ
\mu

is a probability measure, new conditional versions of the above theorems are obtained.
Localizing virtual cycles for Donaldson-Thomas invariants of Calabi-Yau 4-folds
Authors: Kiem Young-Hoon , Park Hyeonjun
Published: May 2023

In 2020, Oh and Thomas constructed a virtual cycle

[
X

]

v
i
r

∈

A
∗

(
X
)

[X]^{\mathrm {vir}} \in A_*(X)

for a quasi-projective moduli space

X
X

of stable sheaves or complexes over a Calabi-Yau 4-fold against which DT4 invariants may be defined as integrals of cohomology classes. In this paper, we prove that the virtual cycle localizes to the zero locus

X
(
σ
)

X(\sigma )

of an isotropic cosection

σ
\sigma

of the obstruction sheaf

O

b
X

Ob_X

of

X
X

and construct a localized virtual cycle
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="left-bracket upper X right-bracket Subscript normal l normal o normal c Superscript normal v normal i normal r Baseline element-of upper A Subscript asterisk Baseline left-parenthesis upper X left-parenthesis sigma right-parenthesis right-parenthesis">

[
X

]

l
o
c

v
i
r

∈

A
∗

(
X
(
σ
)
)

[X]^{\mathrm {vir}} _\mathrm {loc}\in A_*(X(\sigma ))

. This is achieved by further localizing the Oh-Thomas class which localizes Edidin-Graham’s square root Euler class of a special orthogonal bundle. When the cosection

σ
\sigma

is surjective so that the virtual cycle vanishes, we construct a reduced virtual cycle

[
X

]

r
e
d

v
i
r

[X]^{\mathrm {vir}} _{\mathrm {red}}

. As an application, we prove DT4 vanishing results for hyperkähler 4-folds. All these results hold for virtual structure sheaves and K-theoretic DT4 invariants.
On a discrete framework of hypocoercivity for kinetic equations
Authors: Blaustein Alain , Filbet Francis
Published: May 2023

We propose and study a fully discrete finite volume scheme for the linear Vlasov-Fokker-Planck equation written as an hyperbolic system using Hermite polynomials in velocity. This approach naturally preserves the stationary solution and the weightedL2L^2relative entropy. Then, we adapt the arguments developed in Dolbeault, Mouhot, and Schmeiser [Trans. Amer. Math. Soc. 367 (2015), pp. 3807–3828] based on hypocoercivity methods to get quantitative estimates on the convergence to equilibrium of the discrete solution. Finally, we prove that in the diffusive limit, the scheme is asymptotic preserving with respect to both the time variable and the scaling parameter at play.
Grothendieck rings of Queer Lie superalgebras
Authors: Reif Shifra
Published: May 2023

We determine the Grothendieck rings of the category of finite-dimensional modules over Queer Lie superalgebras via their rings of characters. In particular, we show that theQ\mathbb {Q}-span of the ring of characters of the Queer Lie supergroupQ(n)Q(n)is isomorphic to the ring of Laurent polynomials inx1,…,xnx_{1},\ldots ,x_{n}for which the evaluationxn−1=−xn=tx_{n-1}=-x_{n}=tis independent oftt. We thus complete the description of Grothendieck rings for all classical Lie superalgebras.
Geography of symplectic Lefschetz fibrations and rational blowdowns
Authors: Baykur R. , Korkmaz Mustafa , Simone Jonathan
Published: May 2023

We produce simply-connected, minimal, symplectic Lefschetz fibrations realizing all the lattice points in the symplectic geography plane below the Noether line. This provides a symplectic extension of the classical works populating the complex geography plane with holomorphic Lefschetz fibrations. Our examples are obtained by rationally blowing down Lefschetz fibrations with clustered nodal fibers, the total spaces of which are potentially new homotopy elliptic surfaces. Similarly, clustering nodal fibers on higher genera Lefschetz fibrations on standard rational surfaces, we get rational blowdown configurations that yield new constructions of small symplectic exotic

4
4

–manifolds. We present an example of a construction of a minimal symplectic exotic

C
P

2

#

5

C
P

¯

2

{\mathbb {CP}}{}^{2}\# \, 5 \overline {\mathbb {CP}}{}^{2}

through this procedure applied to a genus–

3
3

fibration.
Griffin Warrior, grave of
Authors: Stocker Sharon R. , Davis Jack L.
Published: May 2023

The Grave of the Griffin Warrior is the name that has been attached to the un-looted Mycenaean Warrior burial that was discovered by a team from the University of Cincinnati to the northeast of the Palace of Nestor at Ancient Pylos, Messenia, Greece. The grave contained the remains of a single male individual who was approximately 1.7 m (5′6″) tall and 30–35 years old when he died. The cause of death is unknown. The “Griffin Warrior” was buried with an incredible wealth of objects, including two gold cups, several silver cups, and multiple bronze vessels. The grave also contained items related to warfare, including a boar’s-tusk helmet, a bronze sword with a gold hilt, a bronze dagger with a gold hilt, and a bronze suit of armour. The name derives from the military kit and an ivory plaque with the image of a griffin.
Atrial fibrillation, transient ischaemic attack and stroke in older people. A themed collection in age and ageing journal
Authors: Mensah Ekow A , Masoli Jane A H , Rajkumar Chakravarthi
Published: May 2023

With an increase in the ageing population, there is a rise in the burden of cardiovascular disease. Age and Ageing have compiled collections of their key cardiovascular themed papers. The first Age and Ageing Cardiovascular Collection focussed on blood pressure, coronary heart disease and heart failure. In this second collection, publications since 2011 were selected with emphasis on atrial fibrillation, transient ischaemic attack (TIA) and stroke. The prevalence of TIA and stroke increases as people get older. In this commentary we summarise studies published in Age and Ageing that bring to the fore the need for a multidisciplinary, person-centred approach to care, conscientious identification of risk factors and their management and prevention strategies, which will inform policy ultimately reducing the burden of cost placed by stroke care on healthcare financing. Read the latest Cardiovascular Collection here.
A Comprehensive Review of Brain Tumour Detection Mechanisms
Authors: Ramtekkar Praveen Kumar , Pandey Anjana , Pawar Mahesh Kumar
Published: May 2023

The brain is regarded as the central part of the human body and has a very complicated structure. The abnormal growth of tissue inside the brain is called a brain tumour. Tumour detection at an early stage is the most difficult task in the discipline of health. In this review article, the authors have deeply analysed and reviewed the brain tumour detection mechanisms which include manual, semi- and fully automated techniques. Today, fully automated mechanisms apply deep learning (DL) methods for tumour detection in brain magnetic resonance images (MRIs). This paper deals with previously published research articles relevant to various brain tumour detection techniques. Review of various types of tumours, MRI modalities, datasets, filters, segmentation methods and DL techniques like long short-term memory, gated recurrent unit network, convolution neural network, auto encoder, deep belief network, recurrent neural network, generative adverse network and deep stacking networks have been included in this paper. It has been observed from the analysis that the use of DL techniques in the detection of brain tumours improves accuracy. Finally, this paper reveals research gaps, limitations of existing methods, challenges in tumour detection and contributions of the proposed article.
Atrial fibrillation is associated with worse short and long-term outcomes in critically ill patients
Authors: Paula S , Oliveira A , Silva J , Santos R , Simoes A , Pereira J G
Published: May 2023

Funding Acknowledgements

Type of funding sources: None.

Background

Atrial fibrillation (AF), either chronic or new onset, is common in critically ill patients. Its epidemiology and relationship with clinical outcomes, and the role of post-discharge anticoagulation, is unknown.

Methods

Single-center retrospective, cohort study, evaluating all patients with AF admitted to a non-cardiac intensive care unit during a 54-month period. Their clinical outcomes at short-term (hospital discharge) and long-term (2-year follow-up) were evaluated.

The hazard ratio (HR) with 95% CI for the 2-year all-cause mortality was computed for the whole population with AF compared with a matched one, without AF (1:2 ratio).

Results

We screened 1357 patients, mean age 75±15.2 years, length of intensive care unit stay 4.7±5.1 days, hospital mortality 26%. We identified 215 (15.8%) patients with AF (66% chronic AF). The 2-year all-cause mortality was similar in patients with chronic or new onset AF (58.5% vs 50.7%, p=0.388). Only 85 patients received anticoagulation following their hospital discharge, mostly with chronic AF (74.5% vs 25.5%, p<0.001). We found no benefit from anticoagulation on the 2-year mortality rate (adjusted HR 1.09, 95% CI 0.63-1.86, p=0.6).

We successfully matched 145 patients with AF with 290 controls. Mortality was higher in patients with AF, either in-hospital mortality or during long-term follow-up (mortality 53.8% vs 36.9%, HR 1.76; 95% CI 1.31-2.37, p=0.001).

Conclusions

Patients with AF, both chronic and new onset, had significantly worse short- and long-term outcomes. No mortality benefit was found from anticoagulation after hospital discharge in patients with AF.
Prevalence of modifiable bleeding risk factors in patient with nonvalvular atrial fibrillation and heart failure
Authors: Cabello Montoya F , Zambrano Del Valle S , Stavtseva Y , Kobalava Z
Published: May 2023

Funding Acknowledgements

Type of funding sources: None.

Background

Despite the clear benefit from direct oral anticoagulants (DOAC) in patients with nonvalvular atrial fibrillation (NVAF) and heart failure (HF), major bleeding events may be devastating when they do occur. Identification and correction of potentially modifiable conditions associated with bleeding risk can minimize hemorrhagic complications of DOAC therapy. Data on prevalence of modifiable bleeding risk factors in a cohort of patients treated with DOACs with coexisted NVAF and HF are lacking.

The purpose of the study was to assess the rate of high-bleeding risk according to HAS-BLED and prevalence of modifiable HAS-BLED score components in patients with NVAF and HF receiving oral anticoagulants.

Methods

The study involved consecutive patients with NVAF and HF taking DOACs (rivaroxaban, apixaban, dabigatran) hospitalized with HF decompensation between January 2020 and May 2022. Bleeding risk was stratified by HAS-BLED score. Modifiable and nonmodifiable bleeding risk factors were identified. Numerical data were expressed as median (interquartile range). P<0.05 was considered significant.

Results

A total of 388 patients (age 73.5 years [66-82], 59.3% males, non-paroxysmal NVAF – 58.8%, CHA2DS2-VASc score 4 [4-5]) were included. Most patients had NYHA class III-IV symptoms (67.9%). Prior myocardial infarction was identified in 37.6%. Median ejection fraction (EF) was 44.5% (34-52). The median HAS-BLED score was 2 (1-3). 26.3% of patients had HAS-BLED score ≥3. The subgroup of patients with NVAF and HF with EF ≤40% had higher bleeding risk compared to those with EF >40% (HAS-BLED ≥3 in 32.1% vs 20.4%, P<0.05). Modifiable and nonmodifiable HAS-BLED score components were identified from study population. Anemia (50.5%), heavy alcohol use or concomitant treatment with antiplatelets, nonsteroidal anti-inflammatory drugs, or paracetamol (21.6%), abnormal renal/liver function (19.6%), uncontrolled hypertension (9.8%) were identified as modifiable bleeding risk factors. Increasing age (78.9%), prior stoke (13.4%) were identified as nonmodifiable bleeding risk factors without significant differences between subgroups of HF. Overall, 10% of patients had nonmodifiable bleeding risk factors only, and 88% had modifiable bleeding risk factors (with or without nonmodifiable risk factors). Abnormal renal/liver function and concomitant treatment/alcohol were more frequent in the subgroup of patients with EF ≤ 40% compared to those with EF > 40% (24.7% vs 10.6%, 28.4% vs 16.8%, respectively; P<0.05).

Conclusion

Every fourth patient with NVAF and HF has high bleeding risk that can be minimized by modifying risk factors in up to 90% of patients. Anemia was the most frequent modifiable bleeding risk factor.
Comparison of baseline non- invasive hemodynamic evaluation among patients with advanced conduction disorders based on high Vs. low peripheral vascular resistance reserve
Authors: Orvin K , Vons S , Barsheshet A , Wiessman M , Golovchiner G , Rusadze G , Kornowski R , Erez A
Published: May 2023

Funding Acknowledgements

Type of funding sources: None.

Introduction

Patients with advanced conduction disorders can have various hemodynamic presentation ranging from cardiovascular shock to an excessive hypertension state. The peripheral vascular resistance has an important role in the physiology of compensation mechanisms related to reduced heart rate. We aimed to compare baseline characteristics among patients with advanced conduction disorders based on high versus low peripheral vascular resistance reserve.

Methods

We performed a non-invasive hemodynamic study using the NicaS system (whole-body bio-impedance monitoring system) in 47 patients who presented with advanced conduction disorder and required pacemaker implantation.

Non-invasive hemodynamic parameters including total peripheral resistance index (TPRI) were measured before and after pacemaker implantation. TPRI reserve was defined as the change between the two TPRI measurements. Patients were categorized to have high or low TPRI reserve. We compared baseline characteristics based on high vs. low TPRI reserve.

Results

There were 27 (56%) patients presented with complete AV block and 21 (44%) with other advanced conduction disorders. The average heart rate at presentation was 38.5±5.3 with cardiac output of 2.5±0.6 and cardiac index of 1.4±0.3. Twenty-three patients were categorized with high TPRI reserve. The mean age of patients with high and low TPRI reserve was 77 ± 11 years and 75 ± 16 years, respectively. The systolic blood pressure at presentation for patients with high TPRI reserve was 176 ± 25 mmHg vs. 156 ± 29 mmHg among patients with low TPRI reserve (p-value=0.016). The diastolic blood pressure was similar among patients having high and low TPRI. High TPRI reserve was not correlated with history of hypertension, lower heart rate, lower cardiac output or cardiac index at presentation.

Conclusion

High systolic blood pressure at presentation of patients with advanced heart conduction disorders is associated with higher peripheral resistance reserve.
Premature ventricular contractions: the role in arterial atherosclerosis pathogenesis
Authors: Germanova O , Usenova A , Galati G
Published: May 2023

Funding Acknowledgements

Type of funding sources: None.

In the list of reasons of atherosclerosis, there are no premature ventricular contractions (PVCs).

Purpose

To study the main arteries hemodynamics in patients with PVCs and to determine their influence on the atherosclerotic process.

Methods

We studied 286 patients with PVCs (group 1 (142) – patients with PVCs less 3000 per 24 hours, 2 (144) – more 3000 per 24 hours. Groups were similar in age, gender, comorbidities. By Doppler-ultrasound and shygmography we determined the parameters of heart biomechanics and main arteries kinetics (common carotid, posterior tibial artery): speed, acceleration, power, work in each phase of heart cycle in systole and diastole, the periods of dominance of outflow over inflow. We valued the contribute to the circulation of the PVs and first post-extrasystolic contraction. The volume of cardiac output and transmitral blood flow were measured by echocardiography. We identified the moment of extrasysyoles' appearance by apex-cardiography and ECG. We classified the PVCs up to the moment of their appearance in cardio cycle: before the mitral valve opening; in rapid ventricular filling phase before or after the transmitral blood flow peak; in slow ventricular filling phase; others (group, allorhythmia).

Results

We identified the following hemodynamic effects of PVCs.

1) The main role in hemodynamic and kinetics changes play the time of PVC’ appearance in cardio cycle and the ability of the first post-extrasystolic contraction to reestablish an adequate resulting blood flow. The maximums of parameters were in first post-extrasystolic contraction in PVCs before the mitral valve opening and before the transmitral peak flow.

2) The prevalence of atherosclerotic process was observed in group 2 (p<0,05). (Carotid bifurcation stenosis hemodynamically not significant in 42 patients in group 2 vs 26 in group 1, significant – 28 vs 8, lower extremities arteries stenoses 37 vs 17, coronary arteries stenoses 74 vs 35, renal arteries stenoses 6 vs 1).

3) Additional stretching of arteries in the first post-extrasystolic pressure wave. It makes conditions for acute and chronic arteries traumatism.

4) Mechanic damage of endothelium and as a result lipid deposition. The "weak places" – are the places of the main effect of the first post-extrasystolic hydraulic shock: aorta arch in large radius, carotid bifurcation, aorta bifurcation.

5) Appearing the stand waves, interferention and diffraction in the places of already existing atheromas. Atheroma is deforming, the integrity of atheroma’s cover is violated and there’re appearing the atheroma’s complications: dissections, wall thrombus of hemodynamically important stenosis.

Conclusion

PVCs change intra-arterial hemodynamics and can cause the mechanical injury of intima, as well as the injury of existing atherosclerotic plaques that can lead to progressing of atherosclerosis. We suppose to include the PVCs in the list of risk factors of atherosclerosis.
Value of programmed electrical stimulation in Brugada Syndrome: a cohort study
Authors: Devesa Neto V , Correia J , Fiuza J , Santos L F
Published: May 2023

Funding Acknowledgements

Type of funding sources: None.

Introduction

Prognostic value of programmed electrical stimulation (PES) in Brugada Syndrome (BrS) remains controversial. Substantial controversy exists regarding usefulness of PES in identifying BrS patients at risk of sudden cardiac death (SCD). Implantation of an implantable cardioverter-defibrillator is the only reliable form of SCD prevention in this specific population

Purpose

To determine if induction of sustained ventricular arrhythmia (VA) in PES is a predictor of cardiac events (CE), defined as the composite of SCD, appropriate ICD therapy for VA or unexplained syncope.

Methods

A retrospective analysis of 34 patients with spontaneous or pharmacologically induced type 1 Brugada pattern, submitted to electrophysiology study with PES between 2015 and 2019 in a Portuguese Center, was performed. Patients were followed for 24 months. Hospital records and monitoring data from cardiac devices were consulted. The Mann-Whitney U test was used for median comparison between groups. Binary logistic regression through the stepwise method was performed to evaluate categorical features.

Results

35% (n=12) and 27% (n=9) had spontaneous type 1 and type 2 Brugada pattern in basal electrocardiography, respectively. 23% (n=8) had VA induced by PES. The mean age was 51,2±12,3 years. 71% (n=24) were male. 15% (n=5) had history of cardiac syncope, and 27% (n=9) had a family history of SCD. 9% (n=3) were carriers of a SNC5A mutation. Mean AH time and HV time were, respectively, 105±31,9, and 49±8,5ms. During the 24 months of follow-up, 9% (n=3) suffered a CE (2 unexplained syncope and 1 SCD). None of the patients who suffered CE had VA inducible at PES study. There was no statistical significance in the occurrence of cardiac events when comparing both groups (VA induced in PES vs. no induced arrhythmia) (p=0,49, OR 0,89, IC 95% 0,70;1,02). Through binary logistics, adjusted for potential confounders (gender, history of syncope, history of family SCD and identification of a genetic variant), patients with spontaneous type 1 Brugada pattern in basal electrocardiography were 2,2 times more likely to have a CE (IC 95% 0,12;40,2).

Conclusion

In this population, VA induced by PES was not a predictor of CE during the follow-up period, which highlights the difficulty of risk stratification in patients with BrS. New risk-stratification tools are urgently needed to select those patients at higher-risk of SCD, which are candidates for prophylactic ICD implantation.
Amplitude of spectral area of ventricular fibrillation as a guide for low energy defibrillation level in patients with out-of-hospital cardiac arrest
Authors: Gentile F R , Fasolino A , Wik L , Aramendi E , Isasi I , Steen-Hansen J E , Baldi E , Compagnoni S , Quilico F , Contri E , Palo A , Primi R , Bendotti S , Currao A , Savastano S
Published: May 2023

Funding Acknowledgements

Type of funding sources: None.

Introduction

The optimal energy level for shock in biphasic waveform defibrillation represents a significant knowledge gap. Different energy regimens have been trialed; however, a selection criterion which may help in adopting one approach over another has never been identified. Choosing the maximum energy may be an option but current-induced myocardial damage should not be neglected and an effort to tailor energy delivery is desirable.

Purpose

To assess whether amplitude spectral area (AMSA) of VF can guide the dose-regimens of defibrillation in out-of-hospital cardiac arrest (OHCA) patients.

Methods

This is a multicenter study based on the data from some of the largest OHCA registers in Europe, which enrolled 830 OHCA patients who received at least one shock during advanced resuscitation. AMSA values were calculated by retrospectively analyzing the data collected by the Corpuls 3 and LIFEPAK 12/15 monitors/defibrillators and by using a 2-second-pre-shock ECG interval.

Results

Among 830 OHCAs, 2135 shocks were delivered from a minimum energy level of 150 J to a maximum of 360 J. The AMSA values of efficacious shocks delivered at 150 J were higher compared to those of efficacious shock at 360 J [13.1 (IQR 10.2-17.1) vs 11.8 (IQR 8.3-15.2) HzxmV; p<0.01). In a multivariate analysis corrected for time to each shock, sex, age, amiodarone administration and study center, AMSA values, and not the dose of the shock energy, was significantly associated with the probability of shock success [OR 5.8, (95%CI 4.7-7.3); p< 0.01]. By dividing the total shocks into three tertiles based on AMSA values (T1: 0.8-6.9 Hz×mV; T2: 6.9-11.8 Hz×mV; T3: 11.8-63.2 Hz×mV), the rate of shock success at low energy was significantly higher in the tertile with highest AMSA values (T3: 38% vs T2: 15% vs T1: 5%; p<0.01). Particularly in T3, low energy was more effective than high energy shocks (38% vs 23%, p < 0.001).

Conclusion

This is the first study to identify a datapoint to guide decision-making with regards to defibrillation with lower energy levels. AMSA could indeed guide the selection of energy levels in order to optimize efficaciousness in restoring a perfusing rhythm while minimizing the contribution to myocardial dysfunction.