bluuebunny/crossref_metadata_2025 huggingface dataset:
Mangrove Area Delineation using Object-Based Classification on Sentinel-2 Imagery: Tuba Island, Langkawi
Authors: Mokhtar Ernieza Suhana , Majid Mohamad Amirul Afif Abdul , Norman Masayu , Roslani Muhammad Akmal , Nasirun Noraini , Mohammad Zuraihan
Published: May 2022

Pixel misclassification is a common problem when satellite imagery extracts land-use and land cover classes. Accurate image classification for mangrove areas is essential for management and monitoring to preserve the mangrove ecosystem and expedite the mangrove area delineation process. Therefore, this study aims to i) identify suitable segmentation parameters value to delineate the mangrove area and ii) classify young and mature mangrove trees using the object-based classification (OBIA) approach at Tuba Island, Langkawi, Malaysia. This research applied Support Vector Machine (SVM) based on an object-based method using Sentinel-2A image and segmentation parameters value of scale, compactness, shape, and Gray Level Co-occurrence Matrix (GLCM) mean were tested. Measured tree diameter at breast height (DBH) is used to verify the mangrove tree delineated on the Sentinel-2A image. Segmentation parameters setting of shape (0.2), compactness (0.2), and scale (50) shows minimum errors with mangrove delineation 9.279% as compared to the Global Forest Watch (GFW) data while GLCM mean appropriate to determine the young and mature mangrove tree. The finding of this study will help the Department of Fisheries Malaysia and agritourism to maintain the mangrove ecosystem and enhance the fisheries industry.
Pollutants distribution using environmetric technique in surface water sited at Gebeng, Kuantan, Pahang, Malaysia.
Authors: Wahab Siti Umi Kalthum Ab , Chowdhury Ahmed Jalal Khan , Aris Mohd Shukri Mohd , John Akbar , Hamid Azzmer Azzar Abdul , Mohamad Mohd Azrul Naim
Published: May 2022

The quick response of contaminants from various sources and the extensive deterioration of rivers’ water quality may harm our biodiversity, aquatic creatures, and environment. The depletion of this river water quality can be caused by both natural and manmade factors and this condition will jeopardize its use for many human uses and may harm the residents’ health. Our concerning phenomenon prompted this investigation to study the primary pollutant source in two rivers near Gebeng. A total of ten sampling stations from both Balok and Tunggak Rivers were selected and physicochemical parameters reading were measured monthly afore and in COVID-19 Pandemic spread in Malaysia from March 2019 to October 2020. Later, the Cluster and Principal Component Analysis (CA and PCA) were applied. CA grouped the ten sampling stations into three clusters which are upstream areas that were considered as most polluted. PCA yields only four significant components that represented 90.68% of the total variability. The findings of this study can provide useful information regarding the current state of river water quality in the Gebeng area, and the proposed method can be used as a strategy for sustaining the use of water resources in support of long-term development goals.
Burseraceae in Kuala Keniam and Surrounding Area at Taman Negara Pahang, Peninsular Malaysia
Authors: Ahmad Fitri Z , Nik Hazlan N H , Sarmin S N , Kusin M , Ariff Engku Azlin Rahayu Engku , Hashim T T M Z , Yamani S A K , Nazip S , Nik Norafida N A , Nizam M S , Latiff A
Published: May 2022

A preliminary survey on Burseraceae diversity was conducted in Kuala Keniam and surrounding area at Taman Negara Pahang, Peninsular Malaysia. The data from recent scientific expedition in early September 2020 were compiled with the previous collections lodged in the Herbarium of Universiti Kebangsaan Malaysia (UKMB), Herbarium of Forest Research Institute Malaysia (KEP), Herbarium of University of Malaya (KLU) and Herbarium of Singapore Botanic Gardens (SING). A total of 19 taxa of Burseraceae from five genera were listed in this area. Santiria and Dacryodes represented the highest species with six (6) taxa each followed by Canarium with five (5) species. The common species that we have counted around Kuala Keniam are Canarium littorale and Dacryodes rostrata. From the flora survey, we counted Canarium littorale, C. pilosum, D. costata, D. rostrata, D. rugosa, Santiria griffithii, S. laevigata and Triomma malaccensis. Meanwhile, in the plot study, we counted Canarium littorale, C. pilosum, Dacryodes rostrata, D. rugosa, Santiria laevigata, S. tomentosa and Scutinanthe brunnea.
A Contribution to Trees and Shrubs Checklist in Kuala Keniam at Taman Negara, Pahang, Malaysia
Authors: Ahmad Fitri Z , Nik Hazlan N H , Kusin M , Faezah P , Asmida I , Sarmin S N , Ariff Engku Azlin Rahayu Engku , Hashim T T M Z , Syarifah Haniera S K , Yamani S A K , Nazip S , Nik Norafida N A , Nizam M S , Latiff A
Published: May 2022

The forested area around Kuala Keniam is a part of Taman Negara (Pahang) and is categorized as a primary lowland dipterocarp, riparian fringe and limestone forests. A study of flora that focuses on the trees and shrubs was conducted during the scientific expedition in September 2020, organised by Universiti Teknologi MARA (UiTM). The results identified as many as 187 taxa of trees and shrubs consisting of 124 genera and 49 plant families from the lowland dipterocarp forest. A total of nine endemic taxa to Peninsular Malaysia were also recorded namely Aporosa globifera, Baccaurea pyriformis, Cinnamomum mollissimum, Enicosanthum fuscum, Lithocarpus curtisii, Mallotus griffithianus, M. penangensis, Ryparosa fasciculata and Schoutenia kunstleri. Another three taxa viz. Elaeocarpus obtusatus ssp. apiculatus, Popowia tomentosa and Sterculia rubiginosa var. setistipula were considered as the new additional record for Pahang state. It is hoped that the information from this study can be used as references to help other researchers as well as stakeholders in ecotourism management and forest conservation plan.
Plant Recognition System Using Convolutional Neural Network
Authors: Zefri Wan Muhammad Arief Hilman Bin Wan , Nordin Sharifalillah
Published: May 2022

There are many plant species available to man, even some that have not been discovered. There are species of plants are reported to be on the verge of extinction. Due to the inhumane nature of humans, forest is cleared to make space for industrial purposes. These purposes will lead to the destruction of nature, including plants. Plants are important to be preserved for the future. Plants should be made aware to the public to avoid such disaster. Ensuring they know the plants species are the reasons for the development of this system. The system will ensure people can identify plants without having flipping through research papers or books. Those plants that are similar to one another can be recognized easily. Using convolutional neural network to recognize plant can help the public gain more awareness towards plants species. Using the traditional convolutional neural network for the training of model to recognize plants. The system was tested to get the best accuracy to recognize plants. The images were increased to ensure a better accuracy. This system requires a good model in order to recognize the correct plants. Convolutional neural network is commonly used for image classification due to its high accuracy. The accuracy for the system created in this project is 78.85%. This project can be improved in the future by increasing the accuracy. There are a lot of ways to increase the accuracy such as trying out other CNN architectures or by feeding the system more images. This project involves 7 phases which is preliminary study, knowledge gathering and acquisition, knowledge representation, system design, system development, system testing and evaluation, and documentation.
Notes on Annonaceae from Kuala Keniam and surrounding areas at Taman Negara (Pahang), Peninsular Malaysia
Authors: Ahmad Fitri Z , Nik Hazlan N H , Sarmin S N , Ariff Engku Azlin Rahayu Engku , Hashim T T M Z , Basiron N , Sahalan S , Syarifah Haniera S K , Nazip S , Nik Norafida N A , Nizam M S , Latiff A
Published: May 2022

A brief report on the survey of Annonaceae in Kuala Keniam and surrounding areas of Taman Negara (Pahang), Peninsular Malaysia is given. Based on the collections in the herbarium and in the field a total of 29 genera dan 63 species is listed. In the recent survey in September 2020, a total of 14 taxa was recorded, viz. Alphonsea elliptica, Artabotrys suaveolens, Desmos cochinchinensis, Enicosanthum fuscum, Goniothalamus macrophyllus, Monocarpia euneura, Orophea enterocarpa, Polyalthia cauliflora var. beccarii, P. obliqua, Maasia sumatrana, Popowia pisocarpa, P. tomentosa, Trivalvaria macrophylla and Xylopia magna. Only two taxa, viz. Polyalthia cauliflora var. beccarii bears fruits and flowers while Orophea enterocarpa only bears fruits. These results contributed some additional information of the Annonaceae in Kuala Keniam and surrounding areas of Taman Negara (Pahang).
Notes of Pioneer Species in Kuala Keniam and Surrounding Area at Taman Negara, Pahang, Peninsular Malaysia
Authors: Ahmad Fitri Z , Nik Hazlan N H , Sarmin S N , Kusin M , Ariff Engku Azlin Rahayu Engku , Ahmad Badli Esham , Latif Zulkiflee Abd , Hashim T T M Z , Yamani S A K , Nazip S , Nik Norafida N A , Nizam M S , Latiff A
Published: May 2022

Pioneer species of seed plants are common and important species in the succession. This group of plant occurred everywhere in Peninsular Malaysia especially in the gaps, open areas and roadsides. In this paper we discussed the list of pioneer species found in Kuala Keniam and surrounding area at Taman Negara, Pahang. A total of 16 species of pioneers were recorded from Kuala Keniam and surrounding area at Taman Negara Pahang. Macaranga gigantea is among the common species found especially near the base camp of Kuala Keniam. Only two species of pioneers found in the plot studies, namely Balakata baccata and Cratoxylum formosum. The pioneer is uncommon in the forest except in certain forest gaps and disturbed area. Two species, viz. Mallotus floribundus and Melastoma malabathricum were found on the riverbanks.
Weather Index Based Microinsurance for Agriculture Industry
Authors: Johari Sarah Nadirah Mohd , Asdi Nur Ainina Hanun Mat , Othman Nur Suhaila , Anifruzaidi Sri Dania Qistina
Published: May 2022

Agriculture is particularly susceptible to weather fluctuations. Climate change and agriculture productivity are inextricably linked. Thus, agriculture insurance should be introduced in Malaysia to manage losses and help small farmers to be aid from financial risk that is linked to the impact of the weather conditions on the crop yield. This study presents an investigation on the implementation of weather index based crop insurance contract for the states with the high correlation between the crop production and weather indices. The main aim of the study is to identify the appropriateness of the index insurance to selected crops in different regions in Malaysia. The Rainfall Anamoly Index and Standardized Precipitation Index are chosen in this study. Crop data is detrended to remove presence of time trend before determining the correlation between weather indices. The study continued with the computation of the trigger and exit thresholds for weather indices that corresponds to the crop loss using model-based clustering which will be used to calculate the expected annual loss and pure premium for each crop in different locations. The results showed that only several crops in certain locations are affected by weather. This research also includes farmers’ affordability to pay for premium.
An Assessment of Indoor Air Quality (IAQ) in Foundry Laboratory
Authors: Azmi Affan Ezra , Rashid Amirul Abd , Razak Azli Abd
Published: May 2022

Indoor Air Quality (IAQ) is an important element for a healthy working environment. Working in poor IAQ can lead to sick building syndrome (SBS) with symptoms and troublesome to concentrate in delivering the task. In this study, a preliminary IAQ investigation was carried out at a teaching foundry facility of a higher learning institution in Malaysia. The foundry processes are known to discharge pollutants and gasses. Therefore, this assessment was used to investigate the existence of harmful gasses including Carbon Dioxide (CO2), Carbon Monoxide (CO), particulate matter (PM), and Volatile Organic Compound (VOC) throughout the complete foundry process cycle. An advanced environmental monitor kit was used to monitor the air quality at three different locations within the foundry space to get a good distribution of data. The results reveal that only CO2 and PM10 traces were detected with the reading is still within the allowable range based on guidelines from the Department of Occupational Safety and Health (DOSH), Malaysia. As for thermal comfort result, the Temperature and Relative Humidity (RH) was found to exceeds the benchmark value. Therefore, a more comprehensive and detail thermal comfort study should be conducted to validate the current finding and an appropriate mitigation strategy must be put in place to ensure the thermal comfort of the occupants during the teaching and learning process in the foundry can be improved.
Dynamics of Carbon Stock at Selected Primary Linkages of Central Forest Spine (CFS) Corridors in Peninsular Malaysia
Authors: Omar Hamdan , Roslan Sofiya Zulaikha , Azman Mohammad Shahfiz
Published: May 2022

The Improving Connectivity of the Central Forest Spine Project (IC-CFS) under the United Nations of Development Programme (UNDP) funded by the Global Environment Facility (GEF) and the Malaysian Government (GOM) is aimed at increasing capacity at the Federal and State level to execute the CFS Master Plan. Currently there are 37 CFS corridors that have been identified and prescribed in the CFS Master Plan. Out of this, 17 corridors are classified as Primary Linkages (PL) and 20 as Secondary Linkages (SL), with amounted a total extent of 507,976 ha. The study areas involved three PL corridors, which summing a total area of 35,905 ha, which are PL-1 in Pahang (4,355 ha), PL-2 in Perak (24,759 ha) and PL-3 in Johor (6,791 ha). Accurate assessment and efficient management of these corridors landscape require a systematic geospatial tool. The Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) tool, developed by the Natural Capital Project were chosen to assess the carbon dynamics at the study areas particularly using Carbon model to determine ecosystem services and trade-offs between past (year 2010) and current (year 2020) landuse pattern in the study areas. The study found that there are changes of landuse within the corridors and thus resulted in the changes of carbon stock (C) within the ten years period. PL-1 and PL-2 showed positive increases of 23,690.34 and 830,818.10 Mg C, respectively. However, the other corridor, i.e., PL-3 indicated depletion of C at -523,484.89 Mg C between 2010 and 2020. These fluctuations were due to the conversion of forests to other land use types. Areas that indicated increased in C were undergoing protective actions and conserved the remaining forests within the corridors. The results were presented in spatially distributed maps together with the magnitude of changes. The study also discussed the potential of the InVEST tools in supporting decision making and conservation efforts in CFS and other landscapes in Peninsular Malaysia.
Bioartificial livers: a review of their design and manufacture
Authors: Tuerxun Kahaer , He Jianyu , Ibrahim Irxat , Yusupu Zainuer , Yasheng Abudoukeyimu , Xu Qilin , Tang Ronghua , Aikebaier Aizemati , Wu Yuanquan , Tuerdi Maimaitituerxun , Nijiati Mayidili , Zou Xiaoguang , Xu Tao
Published: May 2022

Acute liver failure (ALF) is a rapidly progressive disease with high morbidity and mortality rates. Liver transplantation and artificial liver (AL) support systems, such as ALs and bioartificial livers (BALs), are the two major therapies for ALF. Compared to ALs, BALs are composed of functional hepatocytes that provide essential liver functions, including detoxification, metabolite synthesis, and biotransformation. Furthermore, BALs can potentially provide effective support as a form of bridging therapy to liver transplantation or spontaneous recovery for patients with ALF. In this review, we systematically discussed the currently available state-of-the-art designs and manufacturing processes for BAL support systems. Specifically, we classified the cell sources and bioreactors that are applied in BALs, highlighted the advanced technologies of hepatocyte culturing and bioreactor fabrication, and discussed the current challenges and future trends in developing next-generation BALs for large-scale clinical applications.
Interaction-induced velocity renormalization in magic-angle twisted multilayer graphene
Authors: Classen Laura , Pixley J H , König Elio J
Published: May 2022

Twistronics heterostructures provide a novel route to control the electronic single particle velocity and thereby to engineer strong effective interactions. Here we show that the reverse may also hold, i.e. that these interactions strongly renormalize the band structure. We demonstrate this mechanism for alternating-twist magic-angle three- and four-layer graphene at charge neutrality and in the vicinity of a phase transition which can be described by an Ising Gross-Neveu critical point corresponding, e.g. to the onset of valley Hall or Hall order. While the non-interacting model displays massless Dirac excitations with strongly different velocities, we show that interaction corrections make them equal in the infrared. However, the renormalization group flow of the velocities and of the coupling to the critical bosonic mode is strongly non-monotonic and dominated by the vicinity of a repulsive fixed point. We predict experimental consequences of this theory for tunneling and transport experiments and discuss the expected behavior at other quantum critical points, including those corresponding to intervalley coherent ordering.
Device-circuit analysis of ultra-thin body In1−x
Ga
x
As on insulator MOS transistor with varying indium mole fraction and channel thickness
Authors: Maity Subir Kumar , Pandit Soumya
Published: May 2022

In this paper, with the help of a well-calibrated simulation study, we explore the design space of ultra-thin body In1−x
Ga
x
As-on-Insulator MOS transistor. We have studied the effect of Indium content, and channel thickness on carrier mobility, different analog figure of merits such as transconductance, transconductance generation factor, output conductance, and intrinsic gain of UTB III–V on Insulator MOS transistor. Moreover, we have analyzed the RF performance of the device in terms of unity gain cut-off frequency and maximum oscillation frequency. To verify frequency response characteristics and DC transfer characteristics, the circuit implementation of the UTB III–V on Insulator MOS transistor was performed on a cascode amplifier and differential amplifier. Our result shows that while increasing channel thickness and Indium content, the carrier transport property of the device improves. With an increase in channel thickness and Indium content, a significant improvement in carrier mobility is observed. Due to the poor electrostatic integrity, off-state current of the device increases with channel thickness and Indium content. Due to enhanced transport property, drain current, transconductance, unity gain cut-off frequency, and maximum oscillation frequency also improve. The improvement in analog and RF figure of Merits are also reflected in circuit performance.
A method for finding the background potential of quantum devices from scanning gate microscopy data using machine learning
Authors: da Cunha Carlo R , Aoki Nobuyuki , Ferry David K , Lai Ying-Cheng
Published: May 2022

The inverse problem of estimating the background potential from measurements of the local density of states is a challenging issue in quantum mechanics. Even more difficult is to do this estimation using approximate methods such as scanning gate microscopy (SGM). Here, we propose a machine-learning-based solution by exploiting adaptive cellular neural networks (CNNs). In the paradigmatic setting of a quantum point contact, the training data consist of potential-SGM functional relations represented by image pairs. These are generated by the recursive Green’s function method. We demonstrate that the CNN-based machine learning framework can predict the background potential corresponding to the experimental image data. This is confirmed by analyzing the estimated potential with image processing techniques based on the comparison between the charge densities and those obtained using different techniques. Correlation analysis of the images suggests the possibility of estimating different contributions to the background potential. In particular, our results indicate that both charge puddles and fixed impurities contribute to the spatial patterns found in the SGM data. Our work represents a timely contribution to the rapidly evolving field of exploiting machine learning to solve difficult problems in physics.
Three-dimensional SnO2 nanoparticles synthesized by joule heating as anode materials for lithium ion batteries
Authors: Jung Woo-Bin , Hong Yu Jin , Yoon Jeesoo , Moon San , Choi Sungho , Kim Do Youb , Suk Jungdon , Chae Oh B. , Wu Mihye , Jung Hee-Tae
Published: May 2022

Tin dioxide (SnO2) is a promising material for use as anodes because of its high theoretical capacity (1,494 mAh g−1). However, a critical limitation is the large change in volume during repeated cycling by pulverization of SnO2, which results in capacity fading. In this study, we enhanced cycle life and reduced capacity fading by introducing the use of three-dimensional SnO2 nanoparticles on carbon nanofibers (CNFs) as an anode material, which is fabricated by simple carbothermal shock through the Joule heating method. Our observations show that the SnO2 nanoparticles are about 50 nm in diameter and are uniformly distributed on CNF, and that the strong connections between SnO2 nanoparticles and CNF are sustained even after repeated cycling. This structural advantage provides high reversible capacity and enhanced cycle performance for over 100 cycles. This study provides insight into the fabrication of anode materials that have strong electric connections between active materials and conductive materials due to the Joule heating method for high-performance lithium ion batteries.
Archimedean zeta functions and oscillatory integrals
Authors: León-Cardenal Edwin
Published: May 2022

This note is a short survey of two topics: Archimedean zeta functions and Archimedean oscillatory integrals. We have tried to portray some of the history of the subject and some of its connections with similar devices in mathematics. We present some of the main results of the theory and at the end we discuss some generalizations of the classical objects.
Generalized Poincaré series for plane curve singularities
Authors: Moyano-Fernández Julio
Published: May 2022

The purpose of these notes is to give an introduction to the notion of Poincaré series attached to multi-index filtrations associated with (plane) complex curve singularities. This was introduced by Campillo, Delgado and Kiyek in 1994 in a purely algebraic-combinatorial viewpoint and further developed in a series of papers by Campillo, Delgado and Gusein-Zade from 1999 on; in particular, they found an alternative definition as an integral with respect to the Euler characteristic, which allowed them to generalize the concept to a setting of motivic nature in 2011. In this review we will summarize the basic facts and results mainly about the generalized Poincaré series. No claim of novelty —beyond the exposition self— is done.
Non-Archimedean electrostatics
Authors: Sinclair Christopher
Published: May 2022

We introduce ensembles of repelling charged particles restricted to a ball in a non-archimedean field (such as the

p
p

-adic rational numbers) with interaction energy between pairs of particles proportional to the logarithm of the (

p
p

-adic) distance between them. In the canonical ensemble, a system of

N
N

particles is put in contact with a heat bath at fixed inverse temperature

β
\beta

and energy is allowed to flow between the system and the heat bath. Using standard axioms of statistical physics, the relative density of states is given by the

β
\beta

power of the (

p
p

-adic) absolute value of the Vandermonde determinant in the locations of the particles. The partition function is the normalizing constant (as a function of

β
\beta

) of this ensemble, and we identify a recursion that allows this to be computed explicitly in finite time. Probabilities of interest, including the probabilities that fixed subsets will have a prescribed number of particles, and the conditional distribution of particles within a subset given a prescribed occupation number, are given explicitly in terms of the partition function. We then turn to the grand canonical ensemble where both the energy and number of particles are variable. We compute similar probabilities to those in the canonical ensemble and show how these probabilities can be given in terms the canonical and grand canonical partition functions. Finally, we briefly consider the multi-component ensemble where particles are allowed to take different integer charges, and we connect basic properties of this ensemble to the canonical and grand canonical ensembles.
Bacterial membrane vesicles with multiple lipid bilayers: vesicles harboring organelle-like structures
Authors: Tashiro Yosuke
Published: May 2022

Bacteria produce outer membrane vesicles (OMVs), which are spherical nanoparticles that are mainly composed of lipopolysaccharides, phospholipids, and outer membrane proteins. OMVs play critical biological roles in stress responses, microbial communication, and bacteria-host interactions. Additionally, they hold great potential for biotechnological applications because of their versatile function in molecular transport while protecting the endogenous substances. While OMVs have been considered lipid monolamellar vesicles for several decades, recent studies have shown that membrane vesicles (MVs) with multiple lipid bilayers, including outer-inner membrane vesicles, multilamellar vesicles and multivesicular vesicles, are also produced by gram-negative bacteria. Some internal vesicles contain cytoplasmic components such as DNA and thus function as organelle-like structures within MVs. This review provides recent findings regarding the biogenesis and properties of MVs with complex structures.
Evaluating hierarchical machine learning approaches to classify biological databases
Authors: Rezende Pâmela M , Xavier Joicymara S , Ascher David B , Fernandes Gabriel R , Pires Douglas E V
Published: May 2022

The rate of biological data generation has increased dramatically in recent years, which has driven the importance of databases as a resource to guide innovation and the generation of biological insights. Given the complexity and scale of these databases, automatic data classification is often required. Biological data sets are often hierarchical in nature, with varying degrees of complexity, imposing different challenges to train, test and validate accurate and generalizable classification models. While some approaches to classify hierarchical data have been proposed, no guidelines regarding their utility, applicability and limitations have been explored or implemented. These include ‘Local’ approaches considering the hierarchy, building models per level or node, and ‘Global’ hierarchical classification, using a flat classification approach. To fill this gap, here we have systematically contrasted the performance of ‘Local per Level’ and ‘Local per Node’ approaches with a ‘Global’ approach applied to two different hierarchical datasets: BioLip and CATH. The results show how different components of hierarchical data sets, such as variation coefficient and prediction by depth, can guide the choice of appropriate classification schemes. Finally, we provide guidelines to support this process when embarking on a hierarchical classification task, which will help optimize computational resources and predictive performance.
ggmsa: a visual exploration tool for multiple sequence alignment and associated data
Authors: Zhou Lang , Feng Tingze , Xu Shuangbin , Gao Fangluan , Lam Tommy T , Wang Qianwen , Wu Tianzhi , Huang Huina , Zhan Li , Li Lin , Guan Yi , Dai Zehan , Yu Guangchuang
Published: May 2022

The identification of the conserved and variable regions in the multiple sequence alignment (MSA) is critical to accelerating the process of understanding the function of genes. MSA visualizations allow us to transform sequence features into understandable visual representations. As the sequence–structure–function relationship gains increasing attention in molecular biology studies, the simple display of nucleotide or protein sequence alignment is not satisfied. A more scalable visualization is required to broaden the scope of sequence investigation. Here we present ggmsa, an R package for mining comprehensive sequence features and integrating the associated data of MSA by a variety of display methods. To uncover sequence conservation patterns, variations and recombination at the site level, sequence bundles, sequence logos, stacked sequence alignment and comparative plots are implemented. ggmsa supports integrating the correlation of MSA sequences and their phenotypes, as well as other traits such as ancestral sequences, molecular structures, molecular functions and expression levels. We also design a new visualization method for genome alignments in multiple alignment format to explore the pattern of within and between species variation. Combining these visual representations with prime knowledge, ggmsa assists researchers in discovering MSA and making decisions. The ggmsa package is open-source software released under the Artistic-2.0 license, and it is freely available on Bioconductor (https://bioconductor.org/packages/ggmsa) and Github (https://github.com/YuLab-SMU/ggmsa).
Cardiovascular complications of catastrophic antiphospholipid syndrome: a case report and review of literature
Authors: Mittal Nitish , Abohelwa Mostafa , Rahman M. Rubayat , Shurmur Scott
Published: May 2022

Background

Antiphospholipid syndrome (APS) is an autoimmune response characterized clinically by arterial or venous thrombosis. One of the rare and series forms of APS is the catastrophic APS (CAPS). The incidence of CAPS has been reported in 0.8% of patients with APS. There have been very few case reports with cardiac involvement in CAPS. Common cardiac manifestations include valvular thickening and lesions, coronary artery disease, and myocardial infarction due to microvascular thrombosis. Here, we are reporting a case of CAPS associated with heart failure and a literature review of similar cases.

Case summary

A 24-year-old woman with a history of APS presented with shortness of breath and right-sided pleuritic chest pain. Computed tomography pulmonary angiogram revealed new pulmonary emboli in the right lung. After 5 days, she developed high-grade fever with negative infectious workup, acute hypoxic respiratory failure with pulmonary oedema, shock, acute kidney injury, and transthoracic echocardiography showed reduced ejection fraction and global hypokinesia. The constellation of multi-organ failure, symptoms within a week, the presence of antiphospholipid antibodies, and exclusion of other causes, CAPS was diagnosed. The patient showed significant improvement with pulse steroids, IV plasmapheresis and got discharged on oral prednisone taper and anticoagulation with home health.

Conclusion

There are different cardiac complications associated with CAPS, including congestive heart failure, acute coronary syndrome, valvular lesions, and thrombus. Heart failure management in CAPS includes triple therapy of intravenous immune globulin, IV plasmapheresis, and corticosteroids rather than conventional treatment.
Modifiable risk factors associated with cardiovascular disease and mortality in China: a PURE substudy
Authors: Li Sidong , Liu Zhiguang , Joseph Philip , Hu Bo , Yin Lu , Tse Lap Ah , Rangarajan Sumathy , Wang Chuangshi , Wang Yang , Islam Shofiqul , Liu Weida , Lu Fanghong , Li Yindong , Hou Yan , Qiang Deren , Zhao Qian , Li Ning , Lei Rensheng , Chen Di , Han Aiying , Liu Guoqin , Zhang Peng , Zhi Yahong , Liu Chunmei , Yang Jinkui , Resalaiti Aobulikasimu , Ma Haibin , Ma Yuanting , Liu Yu , Xing Xiaojie , Xiang Quanyong , Liu Zhengrong , Sheng Yundong , Tang Jinghua , Liu Lisheng , Yusuf Salim , Li Wei
Published: May 2022

Aims

To examine the incidence of cardiovascular disease (CVD) and mortality in China and in key subpopulations, and to estimate the population-level risks attributable to 12 common modifiable risk factors for each outcome.

Methods and results

In this prospective cohort of 47 262 middle-aged participants from 115 urban and rural communities in 12 provinces of China, it was examined how CVD incidence and mortality rates varied by sex, by urban-rural area, and by region. In participants without prior CVD, population-attributable fractions (PAFs) for CVD and for death related to 12 common modifiable risk factors were assessed: four metabolic risk factors (hypertension, diabetes, abdominal obesity, and lipids), four behavioural risk factors (tobacco, alcohol, diet quality, and physical activity), education, depression, grip strength, and household air pollution. The mean age of the cohort was 51.1 years. 58.2% were female, 49.2% were from urban areas, and 59.6% were from the eastern region of China. The median follow-up duration was 11.9 years. The CVD was the leading cause of death in China (36%). The rates of CVD and death were 8.35 and 5.33 per 1000 person-years, respectively, with higher rates in men compared with women and in rural compared with urban areas. Death rates were higher in the central and western regions of China compared with the eastern region. The modifiable risk factors studied collectively contributed to 59% of the PAF for CVD and 56% of the PAF for death in China. Metabolic risk factors accounted for the largest proportion of CVD (PAF of 41.7%), and hypertension was the most important risk factor (25.0%), followed by low education (10.2%), high non-high-density lipoprotein cholesterol (7.8%), and abdominal obesity (6.9%). The largest risk factors for death were hypertension (10.8%), low education (10.5%), poor diet (8.3%), tobacco use (7.5%), and household air pollution (6.1%).

Conclusion

Both CVD and mortality are higher in men compared with women, and in rural compared with urban areas. Large reductions in CVD could potentially be achieved by controlling metabolic risk factors and improving education. Lowering mortality rates will require strategies addressing a broader range of risk factors.
The association of coagulation and hemostasis with atrial fibrillation: a systematic review and meta-analysis
Authors: Tilly MJ , Geurts S , Pezzullo AM , Bramer WM , Ikram MA , De Groot NMS , Kavousi M , De Maat MPM
Published: May 2022

Funding Acknowledgements

Type of funding sources: Public hospital(s). Main funding source(s): - Erasmus MC MRace grant- The Netherlands Organization for the Health Research and Development (ZonMw)

Background

Atrial fibrillation (AF) is a highly prevalent cardiac tachyarrhythmia. Recent literature suggests that AF induces a prothrombotic state, ultimately leading to thrombotic events. It is also hypothesized that coagulation underlies AF development through coagulation.

Purpose

We aimed to assess the associations between selected coagulation factors with AF in both longitudinal and cross-sectional studies, to give further insight on the interaction of coagulation and AF.

Methods

Through a systematic search of large databases, including Embase, Medline ALL, and Web of Science Core Collection, all longitudinal cohort studies and cross-sectional studies published before 25th of May, 2021 were reviewed. For longitudinal studies, pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated through log-transformed HRs and 95% CIs using the generic inverse variance method. For cross-sectional studies the pooled standardized mean differences (SMD) were calculated through inverse variance weighting.

Results

16 longitudinal studies and 44 cross-sectional studies were included. In the longitudinal studies, using complex multivariable models, we found significant associations between fibrinogen (HR1.06, 95% CI 1.01-1.12), Plasminogen activator inhibitor 1 (PAI-1) (HR 1.06, 95% CI 1.00-1.12), and D-dimer (HR 1.10, 95% CI 1.02-1.19), with AF incidence. In cross-sectional studies, we found significant differences between AF patients and controls for fibrinogen (SMD 0.47), D-dimer (SMD 1.74), P-selectin (SMD 0.31), von Willebrand factor (SMD 0.96), PAI-1 (SMD 1.73), ß-thromboglobulin (SMD 0.82), and Platelet Factor 4 (SMD 0.42).

Conclusions

Atrial fibrillation is associated with higher levels of coagulation factors. These associations are most pronounced in cross-sectional analyses, but limited studies are available investigating a prothrombotic state underlying AF initiation. These results further support the hypothesis of "AF begets AF".
Atrial fibrillation progression and burden after the first clinical episode: a prospective observational study via implantable loop recorders
Authors: Papakonstantinou P , Chlouverakis G , Kochiadakis E , Simantirakis E
Published: May 2022

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Medtronic Inc

Background

The progression of atrial fibrillation (AF) after the first clinical AF episode is not well known. AF burden is of clinical significance as it may have clinical implications concerning the long-term management of the arrhythmia and the decision-making on AF patients. Continuous rhythm monitoring via implantable loop recorders (ILRs) can precisely evaluate the AF recurrence profile.

Purpose

To observe the AF progression and AF burden in patients after their first clinical AF episode.

Methods

Thirty consecutive patients (age 66.9 ± 10 years; 14 men) received an ILR after their first clinical AF episode. We recorded the AF recurrences and burden during a follow-up period of three years. We excluded patients with persistent or permanent AF and patients with an episode of AF attributed to reversible or transient causes.

Results

Three patients (10%) had no AF recurrence, whereas 4 patients (13.3%) presented only one episode. Almost half of the patients (46.7%) had a low recurrence rate (<5 episodes/year), whereas the majority of patients (19/30) suffered from episodes with maximum duration ≤24 hours. Eleven patients (36.7%) presented either no episode or a low recurrence rate with episodes lasting ≤24 hours. In 16 patients (53.3%) the AF burden was increased during the second year of follow-up period while in 9 patients (30%) the AF burden was decreased. During the third year of follow-up period the AF burden was increased in 19 patients (63.3%), decreased in 7 patients (23.3%) and remained almost the same in 4 patients (13.3%). Five patients (16.6%) presented at least one episode of persistent AF during the follow-up period. Seven patients (23.3%) suffered only from symptomatic AF episodes, while in nine patients (30%) only asymptomatic AF episodes were recorded. Eleven patients (36.7%) had both types of AF episodes (symptomatic and asymptomatic).

Conclusions

The AF recurrences and burden increased in most AF patients. However, a significant percentage of patients either suffer no AF recurrence after their first symptomatic episode or show a low recurrence rate. Most patients present episodes of short duration. Paroxysmal AF clinical profile differed significantly among the patients. If these findings are confirmed in larger studies, they could have clinical implications ensuring individualized management of the arrhythmia in the future in newly diagnosed AF patients.
Preventive role of angiotensin receptor blockers on the recurrent AF in hypertensive patients
Authors: Hazarapetyan LG , Grigoryan SV , Zelveian PA , Stepanyan AA
Published: May 2022

Funding Acknowledgements

Type of funding sources: None.

Background

The structural remodeling makes important contributions to the AF substrate. The formation of connective tissue in response to injury (cardiac fibrosis) is a hallmark of arrhythmogenic structural remodeling. The atrial fibrosis decrease can be helpful in preventing the onset and recurrence of AF. Inflammatory mechanisms may form a basis for new agents more likely to prevent recurrent episodes of AF. The renin-angiotensin-aldosterone system plays an important role in the pathogenesis of AF in correlation with the inflammatory process. The aim of this study is to access the role of long-term treatment by sartans on the regression of left heart remodeling and the frequency of AF recurrence after successful cardioversion in hypertensive patients.

Methods

We have follow up 119 hypertensive patients with paroxysmal / persistent AF after successful cardioversion during 10-12 months. All patients divided into two groups: group A (62 patients) treated by Losartan daily dose 50 -100 mg or Valsartan daily dose 160mg for 10-12 months. As a control group B of similar 57 patients received standard antihypertensive therapy, but without taking sartans. Both groups were received supporting antiarrhythmic therapy with Аmiodarone (200-300 mg daily). The patients underwent clinical examination, echocardiography, ECG Holter monitoring and determination of plasma levels of inflammatory and fibrosis markers - high sensitivity C-reactive protein (hsCRP), interleukin 6 (IL-6) and profibrotic cytokine - transforming growth factor beta (TGF-β1) by ELIZA. Statistical analysis was performed by SPSS-16.

Results

The obtained results have shown that it was no significant differences of the antihypertensive effect in both patients groups. But the obtained data of structural remodeling regression in A and B groups were differed significantly. Thus, in the A group decrease in LVTDV, TMZHP and LVEDD and an improvement in left ventricular diastolic function were revealed, on compared to the B group which showed only a tendency to improve these indicators. Moreover, in group A, there was a significant decrease in the concentration of inflammation and fibrosis markers compared with the control group. We obtained a positive correlation between hsCRP and LAD (r=0.58, p<0.001) and LVEDD (r=0.51, p<0.001), between TGF-β1 and LAD (r=0.55, p<0.001), LVEDD (r=0.59, p<0.001) and number of AF episodes (r=0.489, p<0.001.). The negative correlation was found between hsCRP and TGF-β1 (r=-0.36, p<0.01). It was revealed that in a group recurrence of AF was less than in B group (6.8% vs 10%).

Conclusion

These results confirmed that the use of angiotensin receptor blockers improves some cardiac remodeling parameters, decreases the frequency of AF recurrence in hypertensive patients with successful cardioversion and contributes to prevent AF episodes.
Omecamtiv mecarbil in heart failure with reduced ejection fraction: systematic review and meta-analysis
Authors: Shalaby M , Sayed A , Awad AK , Moustafa K , Okasha O , Hariri E , Abdelfattah OM
Published: May 2022

Funding Acknowledgements

Type of funding sources: None.

Background

Heart failure (HF) is a growing public health challenge worldwide, with high rates of mortality and morbidity. Omecamtiv Mecarbil (OM) is a cardiac myosin activator and the first of a novel class of myotropes, agents that directly improve myocardial function by selectively improving cardiac sarcomere function. Data on its effect on cardiovascular outcomes remains scarce.

Objectives

To evaluate the safety and efficacy of Omecamtiv Mecarbil in Heart Failure with Reduced Ejection Fraction (HFrEF) and its effect on mid-term clinical outcomes.

Methods

We systematically searched MEDLINE/Pubmed, CENTRAL, clinicaltrials.gov, and the International Clinical Trials Registry Platform for randomized clinical trials (RCTs) evaluating OM safety and efficacy in HFrEF. Outcomes of interest included all-cause mortality, cerebrovascular events, hospitalization, myocardial infarction (MI), anginal events, atrial fibrillation (AF) or flutter, and hypotension. Data screening and extraction was performed by two independent reviewers. We used a random-effects model using the Dersimonian-Laird and Mantel-Haenszel methods to calculate the risk ratio (RR) with 95% confidence intervals.

Results

A total of 232 records were identified, of which six RCTs (N = 9,547; Omecamtiv: 4,889; Placebo: 4,658) met inclusion criteria. The average age was 64.4 years (standard deviation (SD): 0.82), and 79.0% (N = 7,538) were males. The weighted follow-up duration was 19.4 months. OM was associated with a significant reduction in the incidence of cerebrovascular events (RR: 0.68; 95% CI: 0.51 to 0.91). Moreover, OM was associated with a significant increase in the risk of hypotension (RR: 1.45; 95% CI: 1.03 to 2.02), compared to placebo when utilized as an adjuvant therapy to HF guideline-directed medical therapy (GDMT). No statistically significant difference was noted with all-cause mortality (RR: 1.00; 95% CI: 0.93 to 1.07), hospitalization (RR: 0.96; 95% CI: 0.90 to 1.03), incidence of atrial fibrillation or flutter (RR: 0.79; 95% CI: 0.61 to 1.02), anginal events (RR: 1.32; 95% CI: 0.92 to 1.88) or myocardial infarction (RR: 1.07; 95% CI: 0.84 to 1.36). Heterogeneity was low (I2 = 0%) in all analyses.
Relationship between the spread of coronavirus disease 2019, social frailty and depressive symptoms in patients with heart failure
Authors: Shakuta S , Yamashita M , Kamiya K , Hamazaki N , Nozaki K , Uchida S , Noda T , Ueno K , Maekawa E , Yamaoka-Tojo M , Matsunaga A , Ako J
Published: May 2022

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): the Japan Society for the Promotion of Science (JSPS) KAKENHI

Background

Owing to the spread of coronavirus disease 2019 (COVID-19), people have refrained from going out unnecessarily and have been maintaining social distance. These new lifestyle approaches have affected people physically, psychologically, and socially. Patients with heart failure (HF) are more likely to have social frailty, physical frailty, cognitive impairment, and depressive symptoms, and an overlap of these conditions leads to adverse events. Therefore, multi-domain assessment and understanding of the condition of patients with HF are important for disease management. The spread of COVID-19 is a predicted risk factor for these events, but its impact in patients with HF has not been investigated.

Purpose

We investigated whether the spread of COVID-19 is associated with the development of the multi-domain of frailty in patients with HF.

Methods

Patients who were independent in their daily activities before admission were included in the study. The presence of social frailty (Makizako’s five items), physical frailty (Fried phenotype model), cognitive impairment (Mini-Cog), and depressive symptoms (the Patient Health Questionnaire-2) in patients with HF were assessed at hospital discharge. Logistic regression analyses were used to examine the impact of the spread of COVID-19 on the development of the multi-domain of frailty in patients with HF.

Results

We included 482 patients in this study. Median patient age was 74 years, and 64.5% were male. In multivariate logistic regression analyses, the spread of COVID-19 was significantly associated with the development of social frailty (odds ratio [OR]: 1.15, 95% confidence interval [CI]: 1.02–1.30) and depressive symptoms (OR: 1.14, 95% CI: 1.02–1.27) but not with the development of physical frailty (OR: 1.24, 95% CI: 0.51–3.02) and cognitive impairment (OR: 1.72, 95% CI: 0.80–3.73).

Conclusion

The spread of COVID-19 was associated with the development of social frailty and depressive symptoms in patients with HF. Evaluation of social frailty and depressive symptoms during hospitalization would support disease management and understand their social and psychological conditions specific to the spread of COVID-19.