How to Evaluate the Generalization of Detection? A Benchmark for Comprehensive Open-Vocabulary Detection

Object detection (OD) in computer vision has made significant progress in recent years, transitioning from closed-set labels to open-vocabulary detection (OVD) based on large-scale vision-language pre-training (VLP). However, current evaluation methods and datasets are limited to testing generalization over object types and referral expressions, which do not provide a systematic, fine-grained, and accurate benchmark of OVD models' abilities. In this paper, we propose a new benchmark named OVDEval, which includes 9 sub-tasks and introduces evaluations on commonsense knowledge, attribute understanding, position understanding, object relation comprehension, and more. The dataset is meticulously created to provide hard negatives that challenge models' true understanding of visual and linguistic input. Additionally, we identify a problem with the popular Average Precision (AP) metric when benchmarking models on these fine-grained label datasets and propose a new metric called Non-Maximum Suppression Average Precision (NMS-AP) to address this issue. Extensive experimental results show that existing top OVD models all fail on the new tasks except for simple object types, demonstrating the value of the proposed dataset in pinpointing the weakness of current OVD models and guiding future research. Furthermore, the proposed NMS-AP metric is verified by experiments to provide a much more truthful evaluation of OVD models, whereas traditional AP metrics yield deceptive results. Data is available at \url{https://github.com/om-ai-lab/OVDEval}Comment: Long paper accepted at AAAI 202

The survival of murine hepatitis virus (a surrogate of SARS-CoV-2) on conventional packaging materials under cold chain conditions

IntroductionThe cold chain conditions have been suggested to facilitate long-distance transmission of SARS-CoV-2, but it is unclear how viable the virus is on cold chain packaging materials.MethodsThis study used the MHV-JHM strain of murine hepatitis virus as a model organism to investigate the viability of SARS-CoV-2 on foam, plastic, cardboard, and wood sheets at different temperatures (−40°C, −20°C, and 4°C). In addition, the ability of peracetic acid and sodium hypochlorite to eliminate the MHV-JHM on plastic and cardboard sheets were also evaluated.ResultsThe results indicate that MHV-JHM can survive on foam, plastic, or cardboard sheets for up to 28 days at −40°C and −20°C, and up to 14 days on foam and plastic surfaces at 4°C. Although viral nucleic acids were still detectable after storing at 4°C for 28 days, the corresponding virus titer was below the limit of quantification (LOQ).DiscussionThe study highlights that a positive nucleic acid test result may not indicate that the virus is still viable, and confirms that peracetic acid and sodium hypochlorite can effectively eliminate MHV-JHM on packaging materials under cold chain conditions

PTPσ inhibitors promote hematopoietic stem cell regeneration.

Receptor type protein tyrosine phosphatase-sigma (PTPσ) is primarily expressed by adult neurons and regulates neural regeneration. We recently discovered that PTPσ is also expressed by hematopoietic stem cells (HSCs). Here, we describe small molecule inhibitors of PTPσ that promote HSC regeneration in vivo. Systemic administration of the PTPσ inhibitor, DJ001, or its analog, to irradiated mice promotes HSC regeneration, accelerates hematologic recovery, and improves survival. Similarly, DJ001 administration accelerates hematologic recovery in mice treated with 5-fluorouracil chemotherapy. DJ001 displays high specificity for PTPσ and antagonizes PTPσ via unique non-competitive, allosteric binding. Mechanistically, DJ001 suppresses radiation-induced HSC apoptosis via activation of the RhoGTPase, RAC1, and induction of BCL-XL. Furthermore, treatment of irradiated human HSCs with DJ001 promotes the regeneration of human HSCs capable of multilineage in vivo repopulation. These studies demonstrate the therapeutic potential of selective, small-molecule PTPσ inhibitors for human hematopoietic regeneration

Surface-Confined Two-Dimensional Crystal Growth on a Monolayer

Conventional vapor deposition or epitaxial growth of two-dimensional (2D) materials and heterostructures is conducted in a large chamber in which masses transport from the source to the substrate. Here we report a chamber-free, on-chip approach for growing a 2D crystalline structures directly in a nanoscale surface-confined 2D space. The method is based on a surprising discovery of a rapid, long-distance, non-Fickian transport of a uniform layer of atomically thin palladium (Pd) on a monolayer crystal of tungsten ditelluride (WTe2), at temperatures well below the known melting points of all materials involved. The resulting nanoconfined growth realizes a controlled formation of a stable new 2D crystalline material, Pd7WTe2 , when the monolayer seed is either free-standing or fully encapsulated in a van der Waals stack. The approach is generalizable and highly compatible with nanodevice fabrication, promising to expand the library of 2D materials and their functionalities

Epidermal growth factor augments the self-renewal capacity of aged hematopoietic stem cells.

Hematopoietic aging is associated with decreased hematopoietic stem cell (HSC) self-renewal capacity and myeloid skewing. We report that culture of bone marrow (BM) HSCs from aged mice with epidermal growth factor (EGF) suppressed myeloid skewing, increased multipotent colony formation, and increased HSC repopulation in primary and secondary transplantation assays. Mice transplanted with aged, EGF-treated HSCs displayed increased donor cell engraftment within BM HSCs and systemic administration of EGF to aged mice increased HSC self-renewal capacity in primary and secondary transplantation assays. Expression of a dominant negative EGFR in Scl/Tal1+ hematopoietic cells caused increased myeloid skewing and depletion of long term-HSCs in 15-month-old mice. EGF treatment decreased DNA damage in aged HSCs and shifted the transcriptome of aged HSCs from genes regulating cell death to genes involved in HSC self-renewal and DNA repair but had no effect on HSC senescence. These data suggest that EGFR signaling regulates the repopulating capacity of aged HSCs

Monitoring the Amery Ice Shelf front during 2004−2012 using ENVISAT ASAR data

The Amery Ice Shelf is the largest ice shelf in East Antarctica. It drains continental ice from an area of more than one million square kilometres through a section of coastline that represents approximately 2% of the total circumference of the Antarctic continent. In this study, we used a time series of ENVISAT ASAR images from 2004–2012 and flow lines derived from surface velocity data to monitor the changes in 12 tributaries of the Amery Ice Shelf front. The results show that the Amery Ice Shelf has been expanding and that the rates of expansion differ across the shelf. The highest average annual rate of advance from 2004–2012 was 3.36 m∙d-1 and the lowest rate was 1.65 m∙d-1. The rates in 2009 and 2010 were generally lower than those in other years. There was a low correlation between the rate of expansion and the atmospheric temperature recorded at a nearby research station, however the mechanism of the relationship was complex. This study shows that the expansion of the Amery Ice Shelf is slowing down, reflecting a changing trend in climate and ice conditions in East Antarctica

The Role of Epidermal Growth Factor Receptor Signaling in Hematopoietic Stem Cell Regeneration

Hematopoietic stem cells (HSCs) are capable of self-renewing to maintain the stem cell pool as well as differentiating into different mature blood cells to replenish the blood system. Genotoxic stress, such as chemotherapy and radiation, could induce DNA damage in the HSCs, increasing the risk of malignant transformation and decrease the normal function of HSCs. Therapies to promote DNA repair in HSCs after exposure to genotoxic stress remains not well developed. This dissertation reports that the epidermal growth factor receptor (EGFR) signaling promotes DNA repair in HSCs through activation of the non-homologous end-joining (NHEJ) pathway and regulates HSCs regeneration. Data in this dissertation demonstrates that epidermal growth factor (EGF) treatment reduces DNA damage in HSCs after radiation and chemotherapy. EGFR signaling preferentially enhances the activity of the NHEJ pathway, as indicated by NHEJ specific molecules such as DNA-dependent protein kinase, catalytic subunit (DNA-PKcs), Artemis, and Ku70. Mechanistically, EGF binds and activates EGFR, which subsequently activates Akt, further leading to the activation of DNA-PKcs. Pharmacological inhibition of Akt and DNA-PKcs confirmed the EGFR/Akt/DNA-PKcs pathway for DNA repair in HSCs in vivo. Systemic administration of EGF accelerated the hematopoietic recovery of irradiated or chemotherapy-treated mice without affecting the relapse of acute myeloid leukemia. Conditional suppression of EGFR in the hematopoietic stem and progenitor cells (HSPCs) impaired DNA repair and functional recovery, underlining the necessity of EGFR signaling in DNA repair in HSCs. Moreover, EGF treatment accelerated the recovery of irradiated human bone marrow HSCs shown by immunophenotyping in vitro and multilineage reconstitution in vivo. EGF treated human HSPCs also presented enhanced DNA repair. Whole-genome sequencing of HSPCs from irradiated EGF-treated mice revealed no significant difference in the coding regions in terms of mutation rate compared to irradiated control mice, despite increased intergenic copy number variant mutations. RNA sequencing of HSPCs from irradiated EGF-treated mice displayed no significant alterations of the transcription of leukemogenesis related genes. This thesis project uncovered the EGFR/Akt/DNA-PKcs pathway for NHEJ DNA repair in HSCs and explored the therapeutic potential of EGF to promote human HSCs regeneration

The Role of Epidermal Growth Factor Receptor Signaling in Hematopoietic Stem Cell Regeneration

Hematopoietic stem cells (HSCs) are capable of self-renewing to maintain the stem cell pool as well as differentiating into different mature blood cells to replenish the blood system. Genotoxic stress, such as chemotherapy and radiation, could induce DNA damage in the HSCs, increasing the risk of malignant transformation and decrease the normal function of HSCs. Therapies to promote DNA repair in HSCs after exposure to genotoxic stress remains not well developed. This dissertation reports that the epidermal growth factor receptor (EGFR) signaling promotes DNA repair in HSCs through activation of the non-homologous end-joining (NHEJ) pathway and regulates HSCs regeneration. Data in this dissertation demonstrates that epidermal growth factor (EGF) treatment reduces DNA damage in HSCs after radiation and chemotherapy. EGFR signaling preferentially enhances the activity of the NHEJ pathway, as indicated by NHEJ specific molecules such as DNA-dependent protein kinase, catalytic subunit (DNA-PKcs), Artemis, and Ku70. Mechanistically, EGF binds and activates EGFR, which subsequently activates Akt, further leading to the activation of DNA-PKcs. Pharmacological inhibition of Akt and DNA-PKcs confirmed the EGFR/Akt/DNA-PKcs pathway for DNA repair in HSCs in vivo. Systemic administration of EGF accelerated the hematopoietic recovery of irradiated or chemotherapy-treated mice without affecting the relapse of acute myeloid leukemia. Conditional suppression of EGFR in the hematopoietic stem and progenitor cells (HSPCs) impaired DNA repair and functional recovery, underlining the necessity of EGFR signaling in DNA repair in HSCs. Moreover, EGF treatment accelerated the recovery of irradiated human bone marrow HSCs shown by immunophenotyping in vitro and multilineage reconstitution in vivo. EGF treated human HSPCs also presented enhanced DNA repair. Whole-genome sequencing of HSPCs from irradiated EGF-treated mice revealed no significant difference in the coding regions in terms of mutation rate compared to irradiated control mice, despite increased intergenic copy number variant mutations. RNA sequencing of HSPCs from irradiated EGF-treated mice displayed no significant alterations of the transcription of leukemogenesis related genes. This thesis project uncovered the EGFR/Akt/DNA-PKcs pathway for NHEJ DNA repair in HSCs and explored the therapeutic potential of EGF to promote human HSCs regeneration

Study on Rock-Breaking Depth and Damage Area under Particle Jet Impact

Particle jet impact drilling technology is an efficient method which mainly uses high-velocity particles to break rock. As the important criterion for evaluating rock-breaking effect, rock-breaking depth and damage area were studied in this paper. Firstly, a particle jet impact rock-breaking test device was developed, and laboratory experiments have been carried out. Then, based on the spherical cavity expansion theory, the mathematical model of rock-breaking depth and damage area under particle jet impact was established. Afterward, the effect of water-jet impact velocity, impact angle, and particle diameter on rock-breaking depth and damage area was analyzed by comparing experimental results and mathematical calculation. The results show that rock-breaking depth and damage area would increase with increase of water-jet impact velocity and decrease slightly with increase of particle diameter. And the combination of 8° and 20° is recommended for nozzle layout. The experimental results and mathematical calculation are basically consistent, which could verify the correctness of the mathematical model. The study has significance for development and application of particle jet impact rock-breaking technology and perfection of theoretical research