Investigation into the nature behind the interesting half levitation behavior of claimed superconductor LK-99

A recent article published by Lee et.al. claimed to have successfully achieved superconductivity at room temperature (RT) has become a topical issue. Besides the research paper, Lee and his team provided a demonstration video of LK-99 half levitating (HL) on a magnet. Such interesting HL appearance has drawn tremendous sensation both in academia and the network. However, the true identity of LK-99 still remains unclear, i.e., whether the HL behavior can necessarily indicate the diamagnetism behavior of the sample. Here, we fabricated our own LK-99 samples following the procedures reported by Lee et al. We found quite a few sample pieces showing the typical HL that is similar to those reported. Meanwhile, oxidation during the sample preparation was found to deleterious to acquiring HL in the sample, while furnace cooling or water quenching in the last step revealed little effect. However, our careful observations indicated that those HL pieces are more likely simple ferromagnetic. Then we conducted a comprehensive study on the behavior patterns of typical diamagnetism and ferromagnetic substances interacting with a Nd2Fe14B magnet, and provided instructions to distinguish the characteristics between ferromagnetic and diamagnetic to prevent misunderstanding of LK-99 like levitation behavior

LVOS: A Benchmark for Large-scale Long-term Video Object Segmentation

Video object segmentation (VOS) aims to distinguish and track target objects in a video. Despite the excellent performance achieved by off-the-shell VOS models, existing VOS benchmarks mainly focus on short-term videos lasting about 5 seconds, where objects remain visible most of the time. However, these benchmarks poorly represent practical applications, and the absence of long-term datasets restricts further investigation of VOS in realistic scenarios. Thus, we propose a novel benchmark named LVOS, comprising 720 videos with 296,401 frames and 407,945 high-quality annotations. Videos in LVOS last 1.14 minutes on average, approximately 5 times longer than videos in existing datasets. Each video includes various attributes, especially challenges deriving from the wild, such as long-term reappearing and cross-temporal similar objects. Compared to previous benchmarks, our LVOS better reflects VOS models' performance in real scenarios. Based on LVOS, we evaluate 20 existing VOS models under 4 different settings and conduct a comprehensive analysis. On LVOS, these models suffer a large performance drop, highlighting the challenge of achieving precise tracking and segmentation in real-world scenarios. Attribute-based analysis indicates that key factor to accuracy decline is the increased video length, emphasizing LVOS's crucial role. We hope our LVOS can advance development of VOS in real scenes. Data and code are available at https://lingyihongfd.github.io/lvos.github.io/.Comment: LVOS V

Association between internal pentachlorophenol exposure characteristics and thyroid hormone indices in a community population in Shanghai, China

ObjectiveTo assess the level of internal exposure to PCP in a community population in Shanghai, to investigate the factors affecting the level of PCP, and to analyze the correlation between the exposure and thyroid hormone levels.MethodsA total of 464 residents of a community in Shanghai were selected as the study subjects. A questionnaire survey was conducted to obtain the demographic information, dietary situation, lifestyle and behavioral habits, and disease history of the individuals, and blood samples were collected. Gas chromatography-electron trap was applied to determine the PCP levels in serum. Multicategorical logistic regression analysis was used to analyze the possible influencing factors of PCP exposure in humans. Thyroid hormone levels were used as the dependent variable and serum PCP as the independent variable. Multiple linear regression analysis was used to assess the association between PCP and thyroid hormones in the community population after controlling the confounding factors such as age, gender, literacy, annual personal income, and chronic diseases.ResultsThe detection rate of serum PCP in 464 subjects was 90.3%, and the median serum PCP level was 0.43 μg·L-1. The differences in PCP levels among different age groups were statistically significant. There were no significant differences in PCP levels among different gender and BMI groups. The study of PCP exposure factors showed that age, frequency of using plastic products, consumption of freshwater fish, type of occupation, annual income, and consumption of tea or coffee were the potential influencing factors for PCP exposure. Among them, age, frequency of using plastic products, consumption of tea or coffee, and consumption of freshwater fish were positively associated with PCP levels, and annual personal income was negatively associated with it. The results of multiple linear regression analysis showed that among men, PCP levels were positively correlated with TSH (b=0.105, 95%CI:0.017‒0.313) and negatively correlated with FT4 (b=-0.026, 95%CI:-0.057‒0.004), and among women, PCP levels were positively correlated with TSH (b=0.092, 95%CI:-0.211‒0.904) and FT3 (b=0.017, 95%CI:-0.058‒0.230) and negatively correlated with FT4 (b=-0.013, 95%CI:-0.011‒0.037).ConclusionSerum PCP detection is common among community residents in Shanghai. Different demographic characteristics or behavioral habits may increase or decrease PCP exposure. PCP exposure then affects human thyroid hormone levels

Detection of Host Cell Gene/HPV DNA Methylation Markers: A Promising Triage Approach for Cervical Cancer

Cervical cancer is the most prevalent gynecologic malignancy, especially in women of low- and middle-income countries (LMICs). With a better understanding of the etiology and pathogenesis of cervical cancer, it has been well accepted that this type of cancer can be prevented and treated via early screening. Due to its higher sensitivity than cytology to identify precursor lesions of cervical cancer, detection of high-risk human papillomavirus (HR-HPV) DNA has been implemented as the primary screening approach. However, a high referral rate for colposcopy after HR-HPV DNA detection due to its low specificity in HR-HPV screening often leads to overtreatment and thus increases the healthcare burden. Emerging evidence has demonstrated that detection of host cell gene and/or HPV DNA methylation represents a promising approach for the early triage of cervical cancer in HR-HPV-positive women owing to its convenience and comparable performance to cytology, particularly in LMICs with limited healthcare resources. While numerous potential markers involving DNA methylation of host cell genes and the HPV genome have been identified thus far, it is crucial to define which genes or panels involving host and/or HPV are feasible and appropriate for large-scale screening and triage. An ideal approach for screening and triage of CIN/ICC requires high sensitivity and adequate specificity and is suitable for self-sampling and inexpensive to allow population-based screening, particularly in LMICs. In this review, we summarize the markers of host cell gene/HR-HPV DNA methylation and discuss their triage performance and feasibility for high-grade precancerous cervical intraepithelial neoplasia or worse (CIN2+ and CIN3+) in HR-HPV-positive women.</jats:p

Experimental Investigations on Detonation Initiation Characteristics of a Liquid-Fueled Pulse Detonation Combustor at Different Inlet Air Temperatures

The detonation initiation characteristics of a single tube liquid-fueled pulse detonation combustor (PDC) is investigated at different inlet air temperatures in this paper. The inner diameter of the PDC is 62 mm. Gasoline and air are used as fuel and oxidant, respectively. The inlet air temperature is 288–523 K and the operating frequency of the PDC is 10~30 Hz. The experimental results show that the deflagration to detonation transition (DDT) distance, detonation initiation time, DDT time and jet ignition time decrease with the increasing operating frequency at the same inlet temperature. When the inlet temperature is 288 K, the DDT distance is shortened from 860.5 mm to 787.7 mm as the operating frequency increases from 10 Hz to 30 Hz. The detonation initiation time, the jet ignition time and the DDT time are reduced from 10.01 ms, 7.66 ms and 2.35 ms to 6.55 ms, 4.99 ms and 1.56 ms, respectively. When the inlet air temperature increases, the atomization and evaporation of the gasoline is improved, which also leads to the decrease in the DDT distance, the detonation initiation time, the jet ignition time and the DDT time. For example, when the inlet air temperature increases from 288 K to 523 K at the frequency of 10 Hz, the DDT distance is shortened from 860.5 mm to 747.2 mm and the detonation initiation time, the jet ignition time and the DDT time is reduced to 5.867 ms, 2.51 ms and 1.11 ms, respectively. Additionally, the self-ignition caused by high inner wall temperature occurs when PDC is operating at high frequency under high inlet air temperature

An evaluation of the Shanghai mental health service schizophrenia rehabilitation program

This study aimed to evaluate the effectiveness of a rehabilitation program for people with schizophrenia in Shanghai, China. Thirty-five people with schizophrenia participated in an eight-module program that focused on a range of psychosocial skills, while 38 others received treatment as usual in the community. Participants were assessed at baseline and subsequently at 4-week intervals over 12 weeks using the Positive and Negative Syndrome Scale, Clinical Global Impression Scale, Drug Attitude Inventory, and Personal and Social Performance Scale. The rehabilitation program participants demonstrated significantly better improvement over the course of the program than did the control participants on all measures. The rehabilitation program is effective in addressing psychosocial deficits evident in many people who have schizophrenia, and it should be implemented more widely

Rational design of liquid metal organic frameworks for the enhanced CO2 absorption and their photocatalytic reduction

Metal organic frameworks (MOFs) has been widely investigated as co-catalysts for photocatalysis owing to their unique property for controlling the reaction kinetics. They are generally presented in a solid state. Recent studies have presented MOF in the liquid phase, meanwhile preserving the framework structure. Acting as a co-catalyst, significantly improved efficiency has been realized for photocatalytic CO2 reduction. This concept article focuses on the chemical principle of liquid MOF (LMOF). Their applications in CO2 adsorption and the photocatalytic CO2 reduction have been discussed with showing key examples. In addition, the other relevant applications of LMOF have been presented. </p

Rational design of liquid metal organic frameworks for the enhanced CO2 absorption and their photocatalytic reduction

Metal organic frameworks (MOFs) has been widely investigated as co-catalysts for photocatalysis owing to their unique property for controlling the reaction kinetics. They are generally presented in a solid state. Recent studies have presented MOF in the liquid phase, meanwhile preserving the framework structure. Acting as a co-catalyst, significantly improved efficiency has been realized for photocatalytic CO2 reduction. This concept article focuses on the chemical principle of liquid MOF (LMOF). Their applications in CO2 adsorption and the photocatalytic CO2 reduction have been discussed with showing key examples. In addition, the other relevant applications of LMOF have been presented. </p