Fragment Of Region Research Articles

A Landscape-Clustering Zoning Strategy to Map Multi-Crops in Fragmented Cropland Regions Using Sentinel-2 and Sentinel-1 Imagery with Feature Selection

Crop mapping using remote sensing is a reliable and efficient approach to obtaining timely and accurate crop information. Previous studies predominantly focused on large-scale regions characterized by simple cropping structures. However, in complex agricultural regions, such as China’s Huang-Huai-Hai region, the high crop diversity and fragmented cropland in localized areas present significant challenges for accurate crop mapping. To address these challenges, this study introduces a landscape-clustering zoning strategy utilizing multi-temporal Sentinel-1 and Sentinel-2 imagery. First, crop heterogeneity zones (CHZs) are delineated using landscape metrics that capture crop diversity and cropland fragmentation. Subsequently, four types of features (spectral, phenological, textural and radar features) are combined in various configurations to create different classification schemes. These schemes are then optimized for each CHZ using a random forest classifier. The results demonstrate that the landscape-clustering zoning strategy achieves an overall accuracy of 93.52% and a kappa coefficient of 92.67%, outperforming the no-zoning method by 2.9% and 3.82%, respectively. Furthermore, the crop mapping results from this strategy closely align with agricultural statistics at the county level, with an R2 value of 0.9006. In comparison with other traditional zoning strategies, such as topographic zoning and administrative unit zoning, the proposed strategy proves to be superior. These findings suggest that the landscape-clustering zoning strategy offers a robust reference method for crop mapping in complex agricultural landscapes.

Crystal Structures of Antigen-Binding Fragment of Anti-Osteocalcin Antibody KTM219

Osteocalcin is a useful biomarker for bone formation and bone-related diseases. KTM219 is an anti-osteocalcin C-terminal peptide antibody. The single-chain variable region (scFv) and antigen-binding fragment (Fab) of KTM219 are applicable to the Quenchbody (Q-body) immunoassay. Q-body is a new type of fluorescent immunosensor, which is scFv or Fab labeled with a fluorescent dye. When Q-body binds to its antigen, the fluorescence intensity increases. The highly sensitive detection of antigens by changes in fluorescence intensity is performed in a single step by mixing the sample and reagent. In this study, to reveal the recognition mechanism of the KTM219 antibody and to discuss the structural basis for Q-body, we solved the crystal structures of Fab of the anti-osteocalcin antibody KTM219 and its complex with the antigen osteocalcin C-terminal peptide (BGP-C7). Also, we solved the structure of a KTM219 Fab crystal grown in the presence of a fluorescent dye, carboxytetramethylrhodamine (TAMRA); however, tightly bound TAMRA was not found in the electron density map. We predicted the binding sites of TAMRA in the antigen-binding pocket by docking simulations. These results support the proposed Q-body mechanism. The crystal structures of KTM219 Fab would be useful for further development and improvement of Q-body fluorescent immunosensors.

Conformational Engineering of Flexible Protein Fragments on the Surface of Different Nanoparticles: The Surface-Atom Mobility Rules.

As a newly emerging technology, conformational engineering (CE) has been gradually displaying the power of producing protein-like nanoparticles (NPs) by tuning flexible protein fragments into their original native conformation on NPs. But apparently, not all types of NPs can serve as scaffolds for CE. To expedite the CE technology on a broader variety of NPs, the essential characteristic of NPs as scaffolds for CE needs to be identified. Herein, we investigate the potential of two distinct types of NPs as scaffolds for CE: CdSe/ZnS quantum dots (QDs), an ionic compound NP, and palladium NPs (PdNPs), a metal NP. The results demonstrate that while QDs cannot support the restoration of the native conformation and function of the complementary-determining region (CDR) fragments of antibodies, PdNPs can. The notably disparate outcomes unequivocally show that the mobility of the surface atoms/adatoms of the NPs or the mobility of the conjugating bonds to the NPs is essential for CE, which allows the conjugated peptides to undergo a conformational change from their initial random conformation to their most stable native conformation under the constraints mimicking the native long-range interactions in the original proteins. This discovery opens the door for CE on more NPs in the future.

Priority areas and implementation of ecological corridor through forest restoration to safeguard biodiversity

Ecological Corridors (ECs) are proposed as cost-effective solutions to improve ecological connectivity in fragmented landscapes. Planning the implementation of ECs must take into account landscape features as they affect the viability of the endeavor and the ECs associated costs. A novel set of geoprocessing tools were used to assess (i) economic viability; (ii) socioeconomic cost-effectiveness; and (iii) to determine priority targets for ECs establishment in a highly fragmented region of Atlantic Forest. Landscape features (e.g. size, edge density, number of patches), land use and cover, and Enhanced Vegetation Index data were obtained from remote sensing. Composition and configuration landscape metrics were estimated by geostatistical methods. Study area was represented by 35,344 forest fragments, of which 94% were composed of fragments smaller than 10 hectares in size, leading to a landscape characterized by low connectivity. We identified 13 priority fragments for protection and propose five ecological corridors. These five ECs connect six priority fragments, with a total of 283.93 ha of area to restore, on an estimated cost of nearly US$550.000,00. Conserving the biodiversity of one of the most threatened and fragmented tropical rainforest regions could be promoted at modest costs, through the protection of key fragments and their reconnection in the landscape.

Prevalence of Theileria ovis in sheep and goats in northwestern Saudi Arabia with notes on potential vectors.

The prevalence of Theileria spp. infecting sheep and goats were investigated in two cities and surroundings in northwest Saudi Arabia. Blood samples from 403 sheep and goats from Madina (n = 201) and Tabuk (n = 202) cities (177 from sheep and 226 from goats) were investigated. Blood samples were examined microscopically for the presence of intraerythrocytic bodies suggestive of Theileria as well as they were investigated using molecular techniques. DNA was extracted from blood and ticks and subjected to polymerase chain reaction amplification using specific primers. The primers used amplified a fragment of the 18S rRNA region (450 bp) targeting the hypervariable region IV. A total of 63 ticks belonging to five species were collected from sheep and goats for determination of their involvement of lifecycle of Theileria. Ticks were identified morphologically and confirmed molecularly utilizing cytochrome oxidase C subunit 1 gene (COXI) amplification. The results indicated that: microscopic examination revealed 24 (6%) of the samples investigated showed intraerythrocytic bodies suggestive of Theileria. Positive samples were only obtained from sheep whereas goats yielded negative results. A total of 33 (18.6%) sheep samples were positive for Theileria infection using polymerase chain reaction targeting the partial 18S rDNA and DNA sequencing. Theileria infection was more prevalent in animals that were less than 2 years of age compared with older animals. There was no difference in the prevalence of the infection between male and female sheep in both cities. All positive sheep were detected during the summer and none of the samples collected during the winter were positive. Phylogenetic analysis revealed that the sequences obtained from Theileria species reported in the present study grouped with sequences from Theileria ovis from different countries. Ticks were identified as Hyalomma dromedarii, Hyalomma, marginatum, Hyalomma impeltatum and Hyalomma anatolicum anatolicum. T. ovis DNA was detected from Hyalomma dromedarii and Hyalomma impeltatum suggesting that they are potential vectors of this piroplasm in sheep from Madina and Tabuk cities. This report is considered the first report of T. ovis infecting sheep from Madina and Tabuk, furthermore, it is the first report determining the vectors responsible for transmission of the infection in sheep in northwest Saudi Arabia. The data generated from this study will undoubtedly pave the way for the detection and control of ovine and caprine theileriosis in Madina and Tabuk regions.

The sequence 581Ser-610Val in the fibrinogen Aα chain is responsible for the formation of complexes between plasminogen and αC-regions of fibrin(ogen)

This study aimed to identify the binding sites for plasminogen (Pg) and its kringle-containing fragments within the αC-region of fibrin(ogen). This investigation is crucial while the conversion of fibrinogen into fibrin induces conformational changes that expose binding sites for Pg and tissue-type Pg activator (tPA), facilitating effective zymogen activation on the fibrin surface. Two C-terminal fragments of the Aα chain ‒ 45kDa (225Val-610Val) and 40kDa (225Val-580Lys), were obtained through plasmin hydrolysis of human fibrinogen and subsequently characterized using MALDI TOF mass spectrometry. The interactions of Glu-Pg and Lys-Pg, as well as Pg kringle fragments (K1-3, K4, and K5), with the obtained αC truncated polypeptides were analyzed using ELISA and Western blot techniques with the use of specific antibodies. It was demonstrated that Pg and its fragments K1-3, K4, and K5 interact exclusively with the 45-kDa fragment (225Val-610Val) of the αC region of fibrinogen with high affinity in a concentration-dependent manner (Kd values for Glu-Pg=7.10×10-9M, Lys-Pg=6.01×10-9M, K1-3=1.08×10-7M, K4=5.06×10-7M, and K5=2.50×10-7M). This fragment, unlike the 40-kDa polypeptide (225Val-580Lys), contains the α581Ser-610Val sequence. It was shown that the sequence 581Ser-610Val of fibrinogen Aα-chain, which becomes exposed during the conversion of fibrinogen to fibrin, is essential for the formation of complexes between Pg and αC regions of fibrin(ogen), thereby contributing to the initiation and regulation of fibrinolysis.

High genetic diversity yet weak population genetic structure in European common terns

The common tern (Sterna hirundo) is a migratory seabird experiencing a decline in breeding pairs across several European populations due to various threats, including habitat destruction and human disturbance. This study investigates the population genetic structure and diversity of common terns sampled extensively across three European areas—Northern, Southern Inland and Southern Marine—during the breeding seasons, using 18 microsatellite markers and a mitochondrial DNA control region fragment. High genetic diversity was found in both types of markers, with the Southern Marine group showing the lowest overall diversity, although signals of possible population bottlenecks were detected in all groups. Various analyses indicated that population genetic structure was weak or absent, suggesting high gene flow among groups. The low genetic differentiation is likely influenced by distinct migration patterns, particularly between Southern Inland and Marine groups. Our results suggest that geographical distance between breeding colonies had minimal effect on population genetic structure. Further studies with tracking devices are needed to clarify how migration dynamics impacts genetic structure in common terns, while conservation efforts should focus on securing multiple breeding sites and currently unoccupied areas to increase options for habitat selection, supporting the species’ genetic diversity and long-term resilience.

EXTH-05. STEM CELL-BASED THERAPEUTIC STRATEGY FOR LEPTOMENINGEAL METASTASIS OF SOLID CANCERS

Abstract Leptomeningeal dissemination (LMD), known as carcinomatous meningitis, presents an extremely poor prognosis with an average life expectancy of 4-6 weeks. Although whole brain/spinal cord irradiation and intrathecal injection of anticancer drugs are sometimes performed, their effects are limited, so new therapeutic strategies for LMD are urgently needed. Based on the following greatest advantage of stem cell (SC) based therapeutic strategy for LMD, we tested its efficacy in LMD of various solid cancers; LMD is a condition in which cancer cells spread within a huge single space without separation, and the SCs with the characteristic of cancer tropism and chemotaxis can reach cancer cells easily; Repetitive intrathecal injection of therapeutic agents for patients is an invasive and risky procedure, but SCs can continuously secrete/release therapeutic agents into the cerebrospinal fluid after a few injections and increase local concentration of therapeutic substances. We have shown that treatment using engineered SCs may be effective treatment option against LMD from breast cancer, lung cancer, and malignant melanoma. Specifically, we reported that engineered allogeneic SCs which simultaneously targeting epidermal growth factor receptor (EGFR) and death receptor (DR) has efficacy for LMD of triple negative breast cancer and non-small cell lung cancer. Also, we reported that SCs releasing oncolytic herpes virus, granulocyte-macrophage colony-stimulating factor (GM-CSF), and single-chain variable region fragments (scFv) against programmed death receptor-1 (PD-1) has efficacy in LMD of malignant melanoma. Overall, we believe that SC therapy has the potential to become a new therapeutic option for LMD in the future.

Mapping Biodiversity Conservation Priorities for Protected Areas for Spatial Optimization: A Case Study in the Songnen Plain, China.

The decline in biodiversity poses a serious threat to natural ecosystems and has become one of the most pressing global environmental issues. Establishing conservation priorities for protected areas (PAs) is one of the most direct and effective biodiversity conservation measures. However, conservation gaps arise as a result of existing problems in spatial layout of PAs, including overlapping protection scopes, artificial fragmentation of natural ecological regions, as well as "over-protection" and "over-exploitation." To optimize the spatial layout of PAs and improve the efficiency of biodiversity conservation, we employed the Habitat Quality module of the Integrated Assessment of Ecosystem Services and Tradeoffs (InVEST) model and the Maximum Entropy (MaxEnt) model to assess the PAs in the Songnen Plain, China. The combined model (MaxEnt-InVEST) revealed that the conservation priorities for PAs in the Songnen Plain occupied a total area of 14,764.14 km2 (10.24% of the total area of the Songnen Plain). The conservation priorities outside PAs occupied a total area of 7858.45 km2 (5.45% of the total area of the Songnen Plain) and were primarily distributed in the northeastern, central, and southwestern regions of the Songnen Plain. This indicated that existing PAs did not offer adequate protection for local biodiversity. The consistency of our combined modeling framework was 72.11%, which enabled a more accurate assessment of biodiversity hotspots and respects the land uses of the Songnen Plain. In addition, the modeling framework successfully created maps of conservation gaps of biodiversity hotspots based on actual species distribution data and considers current land uses. Our study was aimed at optimizing the spatial conservation efficiency of the Songnen Plain by assessing the conservation gaps in the Songnen Plain. It could provide a reference for the future development of a PA system centering on national parks.

Regional specialization: From the geography of industries to the geography of jobs

AbstractOur analysis begins with an empirical investigation of how employment concentration in industries and occupations across regions of the United States has changed over time and how regional specialization has changed. Results show that industry concentration and specialization indices have fallen, while occupation concentration and specialization indices have risen. Using this background as motivation, we develop a model in which the comparative advantage of regions lies in their productivity of supplying functions such as law, finance, advertising and engineering, to multiple sectors. Productivity differences specific to region functions shape the location decisions of industries that use multiple functions and hence determine patterns of regional specialization both in functions and in sectors. A key parameter is the cost of sourcing functions from a different region (fragmentation costs), and we show that a fall in this cost mimics the data: sector concentration and regional specialization fall and function concentration and specialization rise. At high fragmentation costs, regional comparative advantage in sectors determines general equilibrium analogous to a Heckscher–Ohlin model (HO). At low fragmentation costs, comparative advantage in functions drives an equilibrium that has little resemblance to a HO world.

Minilateralism and global governance: effectiveness of hybrid models

ABSTRACT The liberal world order is showing signs of disarray: two recent catastrophes in adjoining parts of the world (the Middle East and South Caucasus) have opened the fissures of the international governance gap; and the continuing ramifications of COVID-19 have already paralysed the world. On top of this post-pandemic disquietude, multiple conflicts this year are either in danger of precipitating or wars have already re-ignited over long-standing continuing conflicts, highlighting the failure of international governance institutions, including the UN system. In recent years, one of the central responses to the multilateral failures at multiple levels has been for states to form ‘narrower’ and ‘more flexible’ frameworks called ‘minilaterals’. Thus minilateralism has been contrasted through the lens of receding multilateralism, which has been a long-standing hallmark of the American-led liberal international order. This paper examines how far global governance would be dependent on minilateralism by exploring this growing trend in the Indo-Pacific and explores how minilateralism models can enhance international governance structures. This paper also attempts to analyse whether minilateralism is a product of regional fragmentation, or whether it can reinvigorate the comatose multilateralism. Then this paper posits that minilateralism helps rejig the chaotic multipolar order and thus re-invent global governance.

A static quantum embedding scheme based on coupled cluster theory.

We develop a static quantum embedding scheme that utilizes different levels of approximations to coupled cluster (CC) theory for an active fragment region and its environment. To reduce the computational cost, we solve the local fragment problem using a high-level CC method and address the environment problem with a lower-level Møller-Plesset (MP) perturbative method. This embedding approach inherits many conceptual developments from the hybrid second-order Møller-Plesset (MP2) and CC works by Nooijen [J. Chem. Phys. 111, 10815 (1999)] and Bochevarov and Sherrill [J. Chem. Phys. 122, 234110 (2005)]. We go beyond those works here by primarily targeting a specific localized fragment of a molecule and also introducing an alternative mechanism to relax the environment within this framework. We will call this approach MP-CC. We demonstrate the effectiveness of MP-CC on several potential energy curves and a set of thermochemical reaction energies, using CC with singles and doubles as the fragment solver, and MP2-like treatments of the environment. The results are substantially improved by the inclusion of orbital relaxation in the environment. Using localized bonds as the active fragment, we also report results for N=N bond breaking in azomethane and for the central C-C bond torsion in butadiene. We find that when the fragment Hilbert space size remains fixed (e.g., when determined by an intrinsic atomic orbital approach), the method achieves comparable accuracy with both a small and a large basis set. Additionally, our results indicate that increasing the fragment Hilbert space size systematically enhances the accuracy of observables, approaching the precision of the full CC solver.

Global-aware Fragment Representation Aggregation Network for image–text retrieval

Image–text retrieval is an important kind of cross-modal retrieval method and has recently attracted much attention. Existing image–text retrieval methods often ignore the relative importance of each fragment (region in an image or word in a sentence) on the global semantic of image or text when aggregating features of image or text fragments, resulting in the ineffectiveness of the learned image and text representations. To address this problem, we propose an image–text retrieval method named Global-aware Fragment Representation Aggregation Network (GFRAN). Specifically, it first designs a fine-grained multimodal information interaction module based on the self-attention mechanism to model both the intra-modality and inter-modality relationships between image regions and words. Then, with the guidance of the global image or text feature, it aggregates image or text fragment features conditioned on their attention weights over global feature, to highlight fragments that contribute more to the overall semantics of images and texts. Extensive experiments on two benchmark datasets Flickr30K and MS-COCO demonstrate the superiority of the proposed GFRAN model over several state-of-the-art baselines.

Modeling the Distribution of the Ota’s Bent-toed Gecko (Cyrtodactylus otai)

The Ota’s bent-toed gecko (Cyrtodactylus otai) was discovered in isolated karst outcrops of Hang Kia Commune, Mai Chau District, Hoa Binh Province, in 2015 and in Chieng Yen Commune, Van Ho District, Son La Province in 2017, in northwestern Vietnam. This gecko is both an endemic and endangered species of Vietnam, and its known range to date is restricted to a severely fragmented and small regions. Hence, to identify more populations and to better understand the distribution patterns of this cryptic species, we conducted field surveys in surrounding regions of the type localities from 2020 to 2023. We discovered eight new populations for C. otai, and expanded the known range of the species in Van Ho District (Son La Province) and Mai Chau District (Hoa Binh Province). We used species occurrence data from previous studies and our field surveys to model the gecko’s distribution using MaxEnt. The model results showed that the distribution of C. otai may include other nature reserves in surrounding regions, such as Pu Hu and Pu Luong (Thanh Hoa), and Ngoc Son – Ngo Luong (Hoa Binh). Based on the model results, there is a possibility that the Ota’s bent-toed gecko also occur in nearby Lao regions. Therefore, future research and conservation initiatives may focus their efforts in such areas to look for new populations of the Ota’s bent-toed gecko, as well as to assess the distribution, habitat, and ecological patterns of this poorly known reptile.

Semisynthetic Phage Display Library Construction: Generation of Single-Chain Variable Fragment Secondary Libraries.

Display of antibody fragments on the surface of M13 filamentous bacteriophages is a well-established approach for the identification of antibodies binding to a target of interest. Here, we describe the third and final step of a three-step method to construct Antibody Libraries for Therapeutic Antibody Discovery (ALTHEA) Libraries. The three-step method involves (1) primary library construction, (2) filtered library (FL) construction, and (3) secondary library (SL) construction. In the third step, described here, the nucleotide sequences encoding the single-chain variable fragments (scFvs) of FLs are amplified by PCR and combined with the heavy- chain CDR3 region (HCDR3) and joining fragments (H3J) obtained from a pool of donors to maximize diversity ("natural H3J fragments"). These natural H3J fragments are amplified with a set of primers designed to capture >95% of the natural H3J repertoire. The resultant fragments replace the neutral H3J fragments of the FLs, resulting in the final semisynthetic secondary libraries. The quality of these libraries is assessed by sequencing clones chosen at random from the libraries, typically 96 clones. These libraries are then ready to be used for phage selections on targets of interest, providing a robust antibody discovery platform.

Revealing Cropping Intensity Dynamics Using High-Resolution Imagery: A Case Study in Shaanxi Province, China

Reliable and continuous information on cropping intensity is crucial for assessing cropland utilization and formulating policies regarding cropland protection and management. However, there is still a lack of high-resolution cropping intensity maps for recent years, particularly in fragmented agricultural regions. In this study, we combined Landsat-8 and Sentinel-2 imagery to generate cropping intensity maps from 2019 to 2023 at a 10 m resolution for Shaanxi Province, China. First, the satellite imagery was harmonized to construct 10-day composite enhanced vegetation index (EVI) time series. Then, the cropping intensity was determined by counting the number of valid EVI peaks within a year. Assessment based on 578 sample points showed a high level of accuracy, with overall accuracy and Kappa coefficient values exceeding 0.96 and 0.93, respectively. We further analyzed the spatiotemporal patterns of cropping intensity and generated a map of abandoned cropland in Shaanxi. The results indicated that cropland in Shaanxi Province was mainly utilized for single-cropping (52.9% of area), followed by double-cropping (35.2%), with non-cropping accounting for 11.9%. Cropping intensity tended to be lower in the north and higher in the south. Temporally, the average cropping intensity of Shaanxi increased from 1.1 to over 1.3 from 2019 to 2023. Despite this upward trend, large areas of cropland were abandoned in northern Shaanxi. These results demonstrate the potential of utilizing Landsat-8 and Sentinel-2 imagery to identify cropping intensity dynamics in fragmented agricultural regions and to guide more efficient cropland management.

The Progression of Epitope-specific Antibody Responses toPlasmodium falciparum Circumsporozoite Protein Following Consecutive Malaria Infections in Naïve Adults: A Repetitive Controlled Human Malaria Infection Study

Abstract Background With an estimated 249 million cases and 608,000 deaths in 2022 malaria continues to cause substantial morbidity and mortality worldwide, mostly in children in Sub-Saharan Africa due to Plasmodium falciparum. Circumsporozoite protein (CSP) coats the surface of the P. falciparum sporozoite and is the target of the two vaccines approved by the World Health Organization (WHO). CSP has three major regions: the N-terminus, the central repeat region, and the C-terminus, which contains highly variable T cell epitopes; only a fragment of the central repeat region and the C-terminus are represented by the two approved vaccines. The junction between the N-terminal Region 1 and the NANP repeat region (“junctional region”) is not represented in the approved vaccines and was recently found to be a target of protective antibody responses. Methods We used a repetitive controlled human malaria infection (rCHMI) model in which eight malaria-naïve participants were infected with P. falciparum up to three times over two years to identify immune responses associated with acquisition of natural immunity. We evaluated samples from the day of each CHMI and 18 days after each CHMI. We measured antibody responses using a peptide microarray inclusive of hundreds of P. falciparum proteins and focused our current study on the response to CSP. The amino acid sequences of CSP from the NF54 strain and 4 additional CSP variants were represented as 16-amino acid peptides with 13-amino acid overlap. Signal intensities at each amino acid position were estimated using a sliding window approach that averaged signals from adjacent overlapping peptides. Participants who comprised a “delayed parasitemia group” (n = 5) had onset of PCR-confirmed parasitemia 13 or more days after the last CHMI, a sign of developing humoral immunity. A “non-delayed parasitemia group” (n = 3) was comprised of those had onset of parasitemia within 12 or fewer days after the last CHMI. Along each amino acid position, the median signal intensities for all CSP variants are presented to describe the participants’ antibody responses at each time point. Wilcoxon signed rank test was used to compare medians between timepoints; p-values < 0.05 without adjustment for multiple comparisons were considered statistically significant. Results After three rCHMIs, participants developed antibody responses to amino acids corresponding to the junctional region and the central repeat region (P<0.05). When participants are grouped by time to parasitemia, those who showed delayed parasitemia development had strong immune responses to the junctional region while the non-delayed group did not. Antibody responses to the C-terminal region were more variable among the 5 CSP variant sequences compared to other regions. Conclusion Our results showed higher junctional region antibody response in participants with delayed time to parasitemia. We also demonstrate variable antibody response to the C-terminal region, a region with known greater genetic variability that has been previously associated with allele-specific vaccine escape and concern for decreased efficacy of current WHO-approved vaccines. Taken together, our results support future vaccine development that focuses on the conserved junctional region over the polymorphic C-terminal region.

Digging into the Interior of Hot Cores with ALMA (DIHCA). IV. Fragmentation in High-mass Star-forming Clumps

Fragmentation contributes to the formation and evolution of stars. Observationally, high-mass stars are known to form multiple-star systems, preferentially in cluster environments. Theoretically, Jeans instability has been suggested to determine characteristic fragmentation scales, and thermal or turbulent motion in the parental gas clump mainly contributes to the instability. To search for such a characteristic fragmentation scale, we have analyzed Atacama Large Millimeter/submillimeter Array (ALMA) 1.33 mm continuum observations toward 30 high-mass star-forming clumps taken by the Digging into the Interior of Hot Cores with ALMA survey. We have identified 573 cores using the dendrogram algorithm and measured the separation of cores by using the Minimum Spanning Tree technique. The core separation corrected by projection effects has a distribution peaked around 5800 au. In order to remove biases produced by different distances and sensitivities, we further smooth the images to a common physical scale and perform completeness tests. Our careful analysis finds a characteristic fragmentation scale of ∼7000 au, comparable to the thermal Jeans length of the clumps. We conclude that thermal Jeans fragmentation plays a dominant role in determining the clump fragmentation in high-mass star-forming regions, without the need to invoke turbulent Jeans fragmentation.

Mechanistic insight into multiple antibody binding to ADAMTS13 in immune thrombotic thrombocytopenic purpura

BackgroundAntibody-mediated inhibition of von Willebrand factor (VWF) cleavage by ADAMTS-13 results in immune thrombotic thrombocytopenic purpura (iTTP). However, the effects of multiple antibody binding to ADAMTS-13 are not fully understood. ObjectivesTo determine how multiple antibodies affect ADAMTS13 activity under various conditions. MethodsSingle-chain fragments of the variable region isolated via phage display from patients with iTTP, FRETS-VWF73, native ADAMTS-13 in normal human plasma, and hydrogen-deuterium exchange plus mass spectrometry were used. ResultsWe found that 2 stimulatory antibodies affect ADAMTS-13 turnover rate more than its substrate recognition. Hydrogen-deuterium exchange plus mass spectrometry revealed that 1 of these 2 stimulatory antibodies bound to the CUB2 domain that presumably interacts with the spacer domain of ADAMTS-13. Spacer domain is targeted by most inhibitory antibodies in iTTP. Both inhibitory and stimulating antibodies could bind ADAMTS-13 simultaneously but when both were present the inhibitory activity predominates. The antibody-mediated stimulation was lost, but the inhibition persisted when a modified substrate with the amino acid residue leucine at position 1603 of VWF was replaced by an alanine (VWF73-L1603A), interfering with active site binding. ConclusionThese results support the hypothesis that the mechanism of action of both stimulatory and inhibitory anti-ADAMTS-13 antibodies in iTTP is through allosteric modification of the catalytic domain and that inhibition of ADAMTS-13 dominates when both are present. Our findings may provide a new avenue of exploration to develop targeted diagnostic and therapeutic approaches in the management of iTTP.

Variation Patterns and Affecting Factors of Plant Alpha Diversity, Beta Diversity and Its Components in Restoration Grasslands on Loess Plateau

ABSTRACTUnderstanding spatiotemporal variation in diversity and identifying key external affecting factors are essential for biodiversity conservation. However, community assembly and species diversity in natural grassland (NG) restoration on the Loess Plateau remain unclear. In this study, we examined α diversity (species richness), β diversity (βtotal), and its components (βrepl and βrich) across 89 grassland communities, which were categorized into five restoration stages: recent grassland (RG), early restoration (ER), middle restoration (MR), later restoration (LR), and NG. Linear mixed models (LMM) were used to analyze the effects of topographic, soil, and landscape factors on diversity. Results showed that α diversity followed an increasing‐decreasing trend across restoration stages (7–21 species m−2), peaking at the MR stage. In contrast, β diversity and its two components declined with duration, with βtotal and βrepl being notably higher in ER than in LR and NG. Differences in βtotal primarily resulted from species replacement (βrepl, 61%–70%), with a smaller contribution from species gain and loss (βrich, 30%–39%). The LMM also revealed that restoration stage was the most important factor affecting plant diversity, explaining 59.3%, 68.4%, 53.5%, and 58.8% of richness, βtotal, βrepl, and βrich, respectively. In comparison, landscape had weaker effects on diversity (17.2%, 24.2%, 46.5%, 39.8%), while topography and soil factors had the least effects. In summary, deterministic processes (restoration stage) dominate natural restoration, but substantial differences persist between restoration grassland and NG. This study provides valuable insights for assessing restoration progress, prioritizing conservation areas, and informing future grassland management in semi‐arid and fragmented regions.