Extension Of Method Research Articles

Panoramic laser communication optical systems for low Earth orbit satellite networking

Laser communication, which is known for its high data rate and large capacity, is a promising solution for future large-scale satellite constellation networking. However, the limited field of view (FOV) of current communication terminals makes establishing inter-satellite links challenging. This paper presents a wide-field optical system for laser communication that addresses the challenge of the limited field of view (FOV) in current satellite terminals. The system links the FOV to the outgoing light rays using vector reflection laws and ray tracing. The aperture extension method gradually enlarges the system’s transmit and receive apertures to meet the inter-satellite communication needs. The optical head was designed by fitting a freeform surface contour based on the data points and XY polynomial coefficients. After optimization, the system achieved an FOV range of ±30∘ to ±70∘ and supported laser communication over 1200 km, with divergence angles meeting the space communication requirements. Comparative analysis shows that freeform surfaces outperform non-spherical designs, offering reduced distortion and an improved modulation transfer function (MTF), and freeform surfaces reduce the beam spread of the system by about 50% and extend the communication range by about 450 km. These results demonstrate the potential of freeform optics for scalable and high-performance satellite communications, providing a theoretical foundation for future satellite networks.

Pattern-Based Sinkhole Detection in Arid Zones Using Open Satellite Imagery: A Case Study Within Kazakhstan in 2023

Sinkholes are significant geohazards in karst regions that pose risks to landscapes and infrastructure by disrupting geological stability. Usually, sinkholes are mapped by field surveys, which is very cost-intensive with regard to vast coverages. One possible solution to derive sinkholes without entering the area is the use of high-resolution digital terrain models, which are also expensive with respect to remote areas. Therefore, this study focusses on the mapping of sinkholes in arid regions from open-access remote sensing data. The case study involves data from the Sentinel missions over the Mangystau region in Kazakhstan provided by the European Space Agency free of cost. The core of the technique is a multi-scale curvature filter bank that highlights sinkholes (and takyrs) by their very special illumination pattern in Sentinel-2 images. Marginal confusions with vegetation shadows are excluded by consulting the newly developed Combined Vegetation Doline Index based on Sentinel-1 and Sentinel-2. The geospatial analysis reveals distinct spatial correlations among sinkholes, takyrs, vegetation, and possible surface discharge. The generic and, therefore, transferable approach reached an accuracy of 92%. However, extensive reference data or comparable methods are not currently available.

Design of Off-Axis Four-Mirror Optical Systems Enabled by Freeform Optics

The off-axis reflective optical system offers several advantages, including the elimination of central obstruction, zero chromatic aberration, and a compact structure. These features make it highly valuable in the domain of space remote sensing. Freeform surfaces transcend the limitations imposed by rotational symmetry, providing significant design flexibility that is particularly effective for correcting non-rotationally symmetric aberrations present in off-axis systems. In this paper, we propose the averaged seed curve extension (A-SCE) method, which facilitates the direct design of an initial structure for freeform off-axis reflective systems. Both focal and afocal off-axis four-mirror freeform optical systems are designed utilizing the A-SCE method, demonstrating an enhanced capability for initial structure design. The results indicate excellent optical performance while maintaining relatively loose processing and assembly tolerances for both systems, thereby enhancing the facilitation of practical implementation.

Two new phenolic constituents from the Aconitum pendulum Busch roots

Two new phenolic compounds aconitol A (1) and B (2), together with three known compounds including one phenolic constituent (3) and two diterpenoid alkaloids (4-5), were isolated from the roots of Aconitum pendulum. Their structures were assigned by HRESIMS, extensive spectral methods and compared with literature data. All obtained compounds (1-5) were tested for their inhibitory activity against NO production in LPS-activated RAW 264.7 macrophages. Compound 1 and 5 showed moderate inhibitory effects.

Five new triterpenoids isolated from mastic: Structural identification and their anti-inflammatory activity.

Five new oleanane-type triterpenoids were isolated from mastic. Their structures including absolute configurations were determined by extensive spectroscopic methods and single-crystal X-ray crystallographic experiments. Compound 1 is distinguished by its rare furan ring. Compounds 3-5 are formed by the oxidative ring-opening reaction of the A ring in oleanane-type triterpenes, while compounds 3 and 4 are nor-triterpenes with a carbon atom missing at the C-28 position. The anti-inflammatory potential of the compounds was anticipated through network pharmacology, followed by a detailed molecular docking analysis. Finally, the anti-inflammatory effects were verified through the establishment of an in vitro model. Notably, compounds 3 and 4 exhibited significant inhibitory effects on NO production in RAW264.7 cells induced by lipopolysaccharide, with IC50 values of 8.68 ± 2.58 and 5.00 ± 3.06 μM, respectively. These values are lower than that of the positive control drug, dexamethasone, which has an IC50 of 9.93 ± 1.17 μM. The significant anti-inflammatory activity of these compounds suggests their potential as treatment candidates for inflammatory diseases.

Lenthening and reconstruction progress of achondroplastic short arm deformity

To describe the characteristics of short arm deformity in patients with achondroplasia, and summarize the progress of its lenthening and reconstruction, so as to provide reference for clinical diagnosis and treatment. The literature on the lenthening of upper limb with achondroplastic short arm deformity at home and abroad in recent years was reviewed, and the characteristics, extension methods, postoperative management, effectiveness evaluation, and related complications of short arm deformity were summarized. Achondroplastic short arm deformity affect the patient's daily perineal hygiene activities. Although the upper limb is proportionately shortened, the humerus is mainly short limb deformity. Bilateral humeral lengthening is a common treatment method, and the traditional lengthening tools are mainly external fixation, guided by Ilizarov distraction osteogenesis concept; intramedullary lengthening is the latest treatment method. Lengthening percentage and healing index are commonly used for clinical evaluation indexes, and complications such as nerve injury may occur during upper limb lengthening. In addition to appearance improvement, achondroplastic short arm lengthening is of great significance in achieving self-management of individual perineal hygiene. Lenthening and reconstruction methods are constantly being innovated and improved.

Detection of Postpartum Depression using Machine Learning

Postpartum depression (PPD) is a prevalent and serious mental health issue that affects a significant number of women after childbirth. Early detection of PPD is crucial for effective intervention, but traditional screening tools often fall short in terms of accuracy and timely prediction. This study focuses on extensive machine learning methods by using psychological and behavioural data from a large survey of postpartum women. Various traditional machine learning algorithms along with CatBoost are implemented in this research. The accuracy of 95.68% demonstrate that the CatBoost-based model outperforms other machine learning models, providing a robust and reliable method for the early detection of postpartum depression.

Drivers and impacts of mobile phone-mediated scaling of agricultural technologies: a meta-analysis

Mobile phone-mediated scaling of agricultural technologies (MPSATs) attracts attention as an effective approach for promoting agricultural development and sustainability. Despite the growing interest, a comprehensive understanding of drivers of MPSAT at the farm level and the evidence base of their impacts remains limited. To fill this gap, we conducted a systematic literature review and meta-analysis of 18 relevant empirical studies covering 10,757 farmers across 12 countries. Meta-analyses reveal that farmers’ innovativeness and full-time farming increase the odds of adopting agricultural technologies. Age, gender, digital skills, mobile phone device ownership, and membership in farmer groups also influence MPSAT but display heterogeneity. Moderation analysis reveals that the development status of countries plays a moderating role in variables such as asset ownership and farm size. Moreover, the results show that using mobile phones as a standalone method increases the odds of adopting agricultural technologies by 2%. In combination with traditional extension methods, this figure rises significantly to 17%. Additionally, MPSAT increases yields by 2%, and profits by 5%, and contributes to a 3% improvement in farmers’ learning outcomes. This study sheds light on the potential and multifaceted nature of MPSAT, providing insights for policymakers and practitioners promoting sustainable agriculture through digital technologies.

Compensating the capacity loss of boron doped ultra-high nickel cathode via elevated sintering temperature

The pursuit of high-energy-density lithium-ion batteries has driven extensive research into ultra-high nickel cathode materials, which enhance the capacity but often face challenges with structural stability and cycling performance. Boron (B) doping was employed to enhance the cycling stability, but sacrifices the initial and subsequent capacity. Here, we report a feasible and novel approach to redeem this capacity loss of ultra-high nickel cathode materials (LiNi0.98Co0.02O2) via elevated sintering temperature. Our study reveals that B doping significantly impacts crystal growth, resulting in reduced crystallinity, refined primary grain size, and increased degree of Li/Ni cation mixing, and hence in the improved cycling stability but remarkably decreased initial capacity. Increasing the sintering temperature of B-doped samples can recover the initial capacity loss while preserving better cycling stability compared to undoped samples. The detailed mechanism is analyzed by in-situ XRD, FIB-TEM, and extensive electrochemical methods. Our study provides new insights and proposes strategies for balancing initial capacity and cycle stability in ultra-high nickel cathode materials.

The use of combined machine learning and in-silico molecular approaches for the study and the prediction of anti-HIV activit

While the number of AIDS-related deaths continues to rise, efforts have been made to transform the disease into a manageable chronic condition. HIV protease inhibitors have become central to combination therapy. As a result, these inhibitors have become a major focus of anti-HIV drug development. This research takes a data-driven approach to drug development through the use of quantitative structure-activity relationship (QSAR) analysis. A dataset of 450 anti-HIV drugs was used to construct and validate models. Using extensive validation methods and various machine learning algorithms, the results clearly showed that the "ET" regression outperformed the other models (“XGB”, “LGBM”, “DT”, “RF”, “GB”, “Bag”, and “HGB”) in terms of goodness of fit, predictivity, generalizability, and model robustness. Promising compounds were subjected to molecular docking and molecular dynamics simulation, resulting in drugs with favourable pharmacokinetic and pharmacodynamic properties that consistently interact with the therapeutic target.

CO2 Fertilisation Counteracts the Negative Effect of Poor Water Quality on the Growth and Photosynthesis of a Great Barrier Reef Coralline Alga

ABSTRACTThe global problem of ocean acidification and localised decline in water quality are major threats to coral reefs worldwide. This study examined the individual and interactive impacts of global and local stressors by investigating the effects of increased seawater pCO2, elevated nutrient concentrations and reduced light levels on linear growth and metabolic rates of the common branching crustose coralline alga Lithophyllum cf. pygmaeum. We found complex interactions between factors on algal growth and photosynthetic rates, but overall, growth was significantly enhanced by pCO2 enrichment under all light and nutrient combinations. This is the first study to report a positive growth response in coralline algae to elevated pCO2 using linear extension methods. In contrast, the combination of reduced light levels and high nutrient concentrations simulating poor water quality conditions reduced algal growth rates by up to 67% (compared to individuals exposed to high light, low nutrients and elevated pCO2). Decreased light levels reduced linear growth, Pgross and Pnet rates by 33%, 18% and 24%, respectively, highlighting the critical role of light in coralline algal physiology. We suggest that poor water quality may counteract any CO2 fertilisation effect under ocean acidification conditions on the growth of coralline algae, and this has implications for coral reef conservation as it emphasises the importance of improving water quality to maintaining coral reef functions. These results further highlight the need for multifactorial experiments to better understand the interplay between global and local processes on coralline algae growth.

Modified Harmonic Current Control and Load Range Extension Method for Single-Stage Isolated DCM Boost AC–DC Converter

Modified Harmonic Current Control and Load Range Extension Method for Single-Stage Isolated DCM Boost AC–DC Converter

Models of ecological renovation of industrial buildings for the creation of shopping, entertainment or recreational complexes

The article examines the key features of the functional planning and spatial architectural treatment of the typological group of public buildings and structures during renovation of industrial buildings in coastal areas in order to create promising models of two different types of multifunctional spaces: a shopping and entertainment complex, and a public park. Both approaches exploit the structural and spatial advantages of these buildings and modern architectural-ecological techniques, such as: adaptive reuse, structural reinforcement, and integration of natural light and environmentally friendly materials. The key differences lie in their focus: shopping and entertainment centers emphasize commercial activities and leisure through a dynamic shopping environment, while public parks give preference to green areas and outdoor recreation, integrating extensive landscape design and environmental sustainability methods into the project. Overall, these renovation models not only improve the urban environment, but also contribute to the well-being of the population and restoration of the environment in the area.

Final results for mapping the Milky Way’s stellar halo with blue horizontal branch stars selected from the Subaru Hyper Suprime-Cam survey

Abstract We select blue horizontal branch stars (BHBs) from the internal data release of the Hyper Suprime-Cam Subaru Strategic Program to reveal the global structure of the Milky Way (MW) stellar halo. The data are distributed over a $\sim$1100 deg$^2$ area in the range of $18.5\lt g\lt 24.5$ mag, so that candidate BHBs are detectable over a Galactocentric radius of $r \simeq 36-575$ kpc. In order to select the most likely BHBs by removing blue straggler stars and other contaminants in a statistically significant manner, we develop and apply an extensive Bayesian method, as described in Fukushima et al. (2019). Our sample can be fitted to either a single power-law profile with an index of $\alpha =4.11^{+0.18}_{-0.18}$ or a broken power-law profile with an index of $\alpha _{\rm in}=3.90^{+0.24}_{-0.30}$ at r below a broken radius of $r_{\rm b}=184^{+118}_{-66}$ kpc and a very steep slope of $\alpha _{\rm out}=9.1^{+6.8}_{-3.6}$ at $r\gt r_{\rm b}$; the statistical difference between these fitting profiles is small. Both profiles are found to show prolate shapes having axial ratios of $q=1.47^{+0.30}_{-0.33}$ and $1.56^{+0.34}_{-0.23}$, respectively. We also find a signature of the so-called “splashback radius” for the candidate BHBs, which can reach as large as $r \sim 575$ kpc, although it is still inconclusive owing to rather large distance errors in this faintest end of the sample. Our results suggest that the MW stellar halo consists of two overlapping components: the in situ inner halo showing a relatively steep radial density profile and the ex situ outer halo with a shallower profile, being characteristic of a component formed from accretion of small stellar systems.

Impact of Small Vessel Disease on Patient Outcomes After Intravenous Thrombolysis for Acute Ischemic Stroke.

Individual cerebral small vessel disease (SVD) markers independently predict poor prognosis after stroke. However, the impact of a single SVD, especially cumulative SVD burden, on outcomes in acute ischemic stroke (AIS) after intravenous thrombolysis remains unclear. This study evaluated the occurrence of SVD in patients with AIS who were treated with intravenous thrombolytic therapy using multimodal magnetic resonance imaging. The study involved patients with AIS who received multimodal magnetic resonance imaging scans before receiving intravenous thrombolytic treatment with recombinant tissue plasminogen activator (rt-PA). Validated scales were used to document each SVD characteristic and measure the overall impact of SVD using an extensive scoring method. Functional outcomes were evaluated using the modified Rankin scale score within a 3-month time frame, with poor outcomes categorized as a modified Rankin scale score of ≥2. Using a logistic regression model while accounting for potential confounding variables, we examined the relation among individual SVD characteristics, the overall SVD impact, and patient outcomes. In total, 282 patients were included. Severe white matter hyperintensities and lacunas were linked to negative clinical results in patients with SVD, even after accounting for age, National Institutes of Health Stroke Scale score at admission, onset to treatment time, and hypertension (odds ratio 2.394, 95% confidence interval 1.246 to 4.6; odds ratio 2.3, 95% confidence interval 1.214 to 4.36, respectively). When evaluating the SVD global burden, a strong association between the SVD score and negative clinical results was observed, except for cases with an SVD score of 2 points. The findings suggest that the presence of pre-existing SVD, particularly characterized by the severity of white matter changes and lacunes, has a detrimental impact on the clinical outcomes of patients with ischemic stroke receiving intravenous rt-PA treatment. In conclusion, this information could be useful for predicting the prognosis of patients with stroke who underwent intravenous rt-PA therapy.

Efficient quantum algorithm for lattice protein folding

Abstract Predicting a protein's three-dimensional structure from its primary amino acid sequence constitutes the protein folding problem, a pivotal challenge within computational biology. This task has been identified as a fitting domain for applying quantum annealing, an algorithmic technique posited to be faster than its classical counterparts. Nevertheless, the utility of quantum annealing is intrinsically contingent upon the spectral gap associated with the Hamiltonian of lattice proteins. This critical dependence introduces a limitation to the efficacy of these techniques, particularly in the context of simulating the intricate folding processes of proteins. In this paper, we address lattice protein folding as a polynomial unconstrained binary optimization problem, devising a hybrid quantum-classical algorithm to determine the minimum energy conformation effectively. Our method is distinguished by its logarithmic scaling with the spectral gap, conferring a significant edge over the conventional quantum annealing algorithms. The present findings indicate that the folding of lattice proteins can be achieved with a resource consumption that is polynomial in the lattice protein length, provided an ansatz state that encodes the target conformation is utilized. We also provide a simple and scalable method for preparing such states and further explore the adaptation of our method for extension to off-lattice protein models. This work paves a new avenue for surmounting complex computational biology problems via the utilization of quantum computers.

Phytochemical Study and In Vitro Antioxidant Activity of Helianthemum cinereum Along with Antitumor Activity of the Isolated trans-Tiliroside and Luteolin 4'-O-β-Xyloside.

Twelve compounds (1-12), kaempferol (1), luteolin (2), luteolin 4'-O-β-xyloside (3), luteolin 4'-O-β-glucoside (4), quercetin 4'-O-β-xyloside (5), kaempferol-3-O-[6″-O-(E)-p-coumaroyl]-β-D-glucoside (trans-tiliroside) (6), protocatechuic acid (7), gallic acid (8), methyl gallate (9), ethyl gallate (10), shikimic acid-3-O-gallate (11), and 3,3',4'-tri-O-methyl-ellagic acid 4-sulfate (12), were isolated and identified from the aerial parts of Helianthemum cinereum (Cav.) Pers (synonym: Helianthemum rubellum C. Presl. All compounds were isolated by applying different chromatographic procedures, such as silica gel, RP-18 and Sephadex LH-20 columns. The structures were elucidated by extensive spectroscopic methods, mainly nuclear magnetic resonance NMR 1D and 2D, and mass spectrometry, as well as by comparison with the reported spectroscopic data. The two organic extracts, ethyl acetate (EtOAc) and butanol (BuOH), were evaluated for their potent phenolic and flavonoid contents using the Folin-Ciocalteu and aluminum chloride colorimetric methods. Furthermore, the antioxidant activity of the two extracts was determined using the DPPH, FRAP, and ABTS methods. Pure trans-tiliroside (6), the main isolated compound, and luteolin 4'-O-β-xyloside (3) were evaluated for their antitumor activity against the lung cancer (A549), melanoma (A375) and pancreatic cancer (Mia PaCa-2 and Panc-1) cell lines by MTT assay.

Correlation Between Agricultural Machinery Fleet and Arable Land Area

The paper examines the dependence of grain and crop production volumes on the availability and utilization of land resources in agriculture. (Research purpose) The study carries out a retrospective analysis of overarching trends and correlation between agricultural land area and the size of the tractor fleet. (Materials and methods) The analysis focuses on the evolution of land use systems and the integration of agricultural lands into economic turnover over three distinct historical periods in Russia: 1920-1940, 1945-1990, and 1991-2022. The study identifies key evolutionary factors and development patterns in the correlation between agricultural land area and tractor fleet capacity. (Results and discussion) The analysis reveals that the industrialization and collectivization programs implemented between 1928 and 1940 led to a significant expansion in agricultural land area, increasing from 113 million to 150 million hectares, and in the tractor fleet, which grew from 27,000 to 531,000 units. In 1945, the sown area reached a low of 113.8 million hectares, with the tractor fleet reduced to 397,000 units. By 1960, the development of virgin and fallow lands had expanded the sown area to 203 million hectares, and the tractor fleet had grown to 1,122,000 units. The study further identified that the highest recorded expansion in sown land area, reaching 210.3 million hectares, occurred in 1985 due to an increase in mechanization, with the tractor fleet peaking at 2,830,000 units. From 1991 to 2022, however, a steady decline in the tractor fleet led to the gradual withdrawal of agricultural land from use. In 1991, the tractor fleet stood at 1,344,200 units, but by 2022, it had decreased by 1,147,400 units, leaving only 196,800 units. The dissolution of the Soviet Union in 1991 and the shift from a state-command to a market economy had a profound impact on the trajectory of Russian agricultural development. (Conclusions) The dynamics of soil use over different periods have reflected both extensive and intensive farming methods. The extensive approach involved expanding agricultural land by developing virgin, fallow, and unused lands. Currently, development follows the intensive path, marked by increased mechanization, automation, chemical use, and higher crop yields.

Harzianolides H-J: Three New Butenolides Isolated from the Fungus Trichoderma harzianum

Background: Marine fungi have been recognized as new sources for the discovery of valuable secondary metabolites, providing lead compounds for drug discovery and development. Objective: The objective of this study was to isolate and identify the secondary metabolites from the marine-derived fungus Trichoderma harzianum ZN-4 and evaluate their antifungal activity. Method: Fungus strain Trichoderma harzianum ZN-4 was initially fermentated using a PDB liquid medium. Subsequently, extensive chromatographic methods were applied to isolate the fermentation cultures of ZN-4, and the chemical structures of isolate compounds were elucidated by 1D and 2D NMR, ECD, and HRESIMS. The antifungal activity was evaluated using the broth microdilution method. Result: Three new butenolides, harzianolides H–J (1–3), were isolated from T. harzianum ZN-4, and cultivated on a sterilized PDB medium. Activity evaluation showed that compounds 1−3 exhibited potent antifungal activity with MIC values of 12.5−100 μg/mL against the phytopathogenic fungus Pestalotiopsis theae. Conclusion: This study not only enriched the structural diversity of the harzianolide family but also revealed their anti-P. theae activity, which may be potential antifungal agents.

Identification and evaluation of human errors in the care of pregnant mothers using the extensive CREAM technique

Background Care of pregnant mothers is one of the most important services provided in the healthcare system. Objective This study aims to identify and evaluate human errors in the care process of pregnant mothers using the extensive Cognitive Reliability and Error Analysis Method (CREAM). Methods In this study, tasks and activities related to the care of pregnant mothers in the health center and hospital were first analyzed using the HTA (hierarchical task analysis). Then, using extensive CREAM, human errors in tasks related to the care of pregnant mothers in the health center and hospital were identified and evaluated. Results In general, 34 main tasks and 106 subtasks were identified in the process of caring for pregnant Mothers. Thirty seven activities are related to midwifery associates or experts, and 19 activities are related to gynecologists. The highest Cognitive Failure Probability total (CFPt) was related to the duties of measures related to the infant, preparing the pregnant mother for transfer to the operating room, routine obstetric measures, taking delivery, measures related to resuscitation, and measures related to the control of the condition after delivery. Conclusions The process of caring for pregnant mothers is very vital and prone to errors due to different levels of service. The presence of experienced and capable personnel can largely prevent the occurrence of human errors. Increasing the number of personnel can be effective in reducing workload and preventing errors.