T2LR-Net: An unrolling network learning transformed tensor low-rank prior for dynamic MR image reconstruction.

The tensor low-rank prior has attracted considerable attention in dynamic MR reconstruction. Tensor low-rank methods preserve the inherent high-dimensional structure of data, allowing for improved extraction and utilization of intrinsic low-rank characteristics. However, most current methods are still confined to utilizing low-rank structures either in the image domain or predefined transformed domains. Designing an optimal transformation adaptable to dynamic MRI reconstruction through manual efforts is inherently challenging. In this paper, we propose a deep unrolling network that utilizes the convolutional neural network (CNN) to adaptively learn the transformed domain for leveraging tensor low-rank priors. Under the supervised mechanism, the learning of the tensor low-rank domain is directly guided by the reconstruction accuracy. Specifically, we generalize the traditional t-SVD to a transformed version based on arbitrary high-dimensional unitary transformations and introduce a novel unitary transformed tensor nuclear norm (UTNN). Subsequently, we present a dynamic MRI reconstruction model based on UTNN and devise an efficient iterative optimization algorithm using ADMM, which is finally unfolded into the proposed T2LR-Net. Experiments on two dynamic cardiac MRI datasets demonstrate that T2LR-Net outperforms the state-of-the-art optimization-based and unrolling network-based methods.

Supramolecular interactions between functional saccharide-based ionic liquids and cellulose macromolecules.

Interactions between polysaccharides and ionic liquids (ILs) at the molecular level are essential to elucidate the dissolution and/or plasticization mechanism of polysaccharides. Herein, saccharide-based ILs (SILs) were synthesized, and cellulose membrane was soaked in different SILs to evaluate the interactions between SILs and cellulose macromolecules. The relevant results showed that the addition of SILs into cellulose can effectively reduce the intra- and/or inter-molecular hydrogen bonds of polysaccharides. Glucose-based IL showed the intensest supramolecular interactions with cellulose macromolecules compared to sucrose- and raffinose-based ILs. Two-dimensional correlation and perturbation-correlation moving window Fourier transform infrared techniques were for the first time used to reveal the dynamic variation of the supramolecular interactions between SILs and cellulose macromolecules. Except for the typical HO⋯H interactions of cellulose itself, stronger -Cl⋯HO hydrogen bonding interactions were detected in the specimen of SILs-modified cellulose membranes. Supramolecular interactions of -Cl⋯H, HO⋯H, C-Cl⋯H, and -C=O⋯H between SILs and cellulose macromolecules sequentially responded to the stimuli of temperature. This work provides a new perspective to understanding the interaction mechanism between polysaccharides and ILs, and an avenue to develop the next-generation ILs for dissolving or thermoplasticizing polysaccharide materials.

Composition characteristics and metal binding behavior of macrophyte-derived DOM (MDOM) under microbial combined photodegradation: A state closer to actual macrophytic lakes.

In actual lakes, the "unstable components" of macrophyte-derived DOM (MDOM) are always degraded and cannot exist abidingly, but the environmental impact brought by it is ignored. In this study, MDOM from Potamogeton crispus was extracted to carry out microbial combined photodegradation (M-Photodegradation) and fluorescence titration experiments. Then the traits and metal binding reaction of MDOM under M-Photodegradation were analysed and compared with the features of lake-derived DOM (LDOM) from point monitoring of Dongping Lake through EEM-PARAFAC, 2D-SF-COS, and 2D-FTIR-COS. The results showed that the features of MDOM after M-Photodegradation were closer to those of LDOM. The degradation amplitudes were 93.53% ± 0.53% for C4 in microbial degradation and 78.31% ± 0.74% for C3 in photodegradation. Correspondingly, both were hardly detected in LDOM. Protein-like substances and aliphatic C-OH were preferentially selected by Cu2+, while humic-like matter and phenolic hydroxyl O-H responded faster to Pb2+. Although the binding sequences remained unchanged after M-Photodegradation, the LogKCu and LogKPb of components decreased overall, indicating increased environmental risks. This study proves that the refractory MDOM retained after degradation was more consistent with the actual state of macrophytic lakes and provides more information for the treatment of heavy metal pollution in lakes.

Difluoroethylene Carbonate as an Electrolyte Additive for Engineering the Electrolyte-Electrode Interphase of Lithium Metal Batteries.

Difluoroethylene carbonate (DFEC) featuring abundant fluorine atoms has been proposed as a multifunctional electrolyte additive to boost the stability of the electrolyte-electrode interphase of lithium metal batteries. Thus, introducing the DFEC additive enables a high capacity retention rate of the Li||NCM811 full cell (up to 75% after 200 cycles) at 4.5 V high voltage.

Application of tangent-arc technology for deep inspiration breath-hold radiotherapy in left-sided breast cancer.

Objective: To explore the advantages of dosimetry and the treatment efficiency of tangent-arc technology in deep inspiration breath-hold radiotherapy for breast cancer. Methods: Forty patients with left-sided breast cancer who were treated in our hospital from May 2020 to June 2021 were randomly selected and divided into two groups. The first group's plan was a continuous semi-arc that started at 145° ( ± 5°) and stopped at 325° ( ± 5°). The other group's plan, defined as the tangent-arc plan, had two arcs: the first arc started at 145° ( ± 5°) and stopped at 85° ( ± 5°), and the second arc started at 25° ( ± 5°) and stopped at 325° ( ± 5°). We compared the target dose, dose in organs at risk (OARs), and treatment time between the two groups. Results: The target dose was similar between the continuous semiarc and tangent-arc groups. The V5 of the right lung was significantly different between the two groups (Dif 5.52, 95% confidence interval 1.92-9.13, t=3.10, P=0.004), with the patients in the continuous semi-arc and tangent-arc groups having lung V5 values of (9.16 ± 1.62)%, and (3.64 ± 0.73)%, respectively. The maximum dose to the spinal cord was (1835.88 ± 222.17) cGy in the continuous semi-arc group and (599.42 ± 153.91) cGy in the tangent-arc group, yielding a significant difference between the two groups (Dif 1236.46, 95% confidence interval 689.32-1783.6, t=4.57, P<0.001). The treatment times was (311.70 ± 60.45) s for patients in the continuous semi-arc group and (254.66 ± 40.73) s for patients in the tangent-arc group, and there was a significant difference in the mean number of treatment times between the two groups (Dif 57.04, 95% confidence interval 24.05-90.03, t=3.5, P=0.001). Conclusion: Both the continuous semi-arc and tangent-arc plans met the clinical prescription dose requirements. The OARs received less radiation with the tangent-arc plan than the continuous semi-arc plan, especially for the lung (measured as V5) and the spinal cord (measured as the maximum dose). Tangent-arc plan took significantly less time than the continuous semi-arc, which can greatly improve treatment efficiency. Therefore, tangent-arc plans are superior continuous semi-arc plans for all cases.

Sequence variety in the CC' loop of Siglec-8/9/3 determines the recognitions to sulfated oligosaccharides.

Siglecs are important lectins found in different types of immune cells and function as regulatory molecules by recognizing self-associated glycans and converting extracellular interactions into signals for inhibiting immune cell functions. Although many Siglecs have been found to show broad specificities and recognize different types of sulfated oligosaccharides, Siglec-8 and Siglec-9 displayed a high degree of specificity for sialyl N-acetyllactosamine (sLacNAc) with sulfations at O6-positions of the galactose (6'-sulfation) and N-acetylglucosamine (6-sulfation), respectively. Siglec-3 was recently discovered to bind sLacNAc both sulfations. In addition to a conserved arginine residue for binding to sialic acid residue, the sequence variety in the CC' loop may provide binding specificities to sulfated oligosaccharides in Siglecs. Thus, the present study employed molecular models to study the impact of different residues in the CC' loops of Siglec-8/9/3 to the recognitions of 6-sulfations in Gal and/or GlcNAc of sLacNAc. The negatively charged residues in the CC' loop of Siglec-9 formed unfavorable electrostatic repulsions with the 6-sulfate in Gal and resulted no recognitions, in contrast to the favorable interactions formed between the positively charged residues in the CC' loop of Siglec-8 and the 6-sulfate in Gal resulting strong specificity. A two-state binding model was proposed for Siglec-3 recognizing 6-sulfations in Gal and GlcNAc of sLacNAc, as the neutral residues in the CC' loop of Siglec-3 could not form strong favorable interactions to lock the 6-sulfate in Gal within a single binding pose or strong unfavorable interactions to repel the 6-sulfate in Gal. The oligosaccharide adopted two distinctive binding poses and oriented the sulfate groups to form interactions with residues in the CC' loop and G-strand. The present study provided a structural mechanism for the sequence variety in the CC' loop of Siglec-8/9/3 determining the recognitions to the sulfated oligosaccharides and offered insights into the binding specificities for Siglecs.

Correlation between the setting of gating window width and setup accuracy in left breast cancer radiotherapy based on deep inspiration breath hold.

Personalized precision irradiation of patients with left-sided breast cancer is possible by examining the setup errors of 3- and 4-mm gated window widths for those treated with deep inspiration breath-hold (DIBH) treatment. An observational study was performed via a retrospective analysis of 250 cone-beam computed tomography (CBCT) images of 60 left-breast cancer patients who underwent whole-breast radiotherapy with the DIBH technique between January 2021 and 2022 at our hospital. Among them, 30 patients had a gated window width of 3 mm, while the remaining 30 had a gated window width of 4 mm; both groups received radiotherapy using DIBH technology. All patients underwent CBCT scans once a week, and the setup errors in the left-right (x-axis), inferior-superior (y-axis), and anterior-posterior (z-axis) directions were recorded. The clinical-to-planning target volume (CTV-PTV) margins of the two gating windows were calculated using established methods. The setup error in the Y direction was 1.69 ± 1.33 mm for the 3-mm - wide gated window and 2.42 ± 3.02 mm for the 4-mm - wide gated window. The two groups had statistically significant differences in the overall mean setup error (Dif 0.7, 95% CI 0.15-1.31, t = 2.48, p= 0.014). The Z-direction setup error was 2.32 ± 2.12 mm for the 3-mm - wide gated window and 3.15 ± 3.34 mm for the 4-mm - wide gated window. The overall mean setup error was statistically significant between the two groups (Dif 0.8, 95% CI 0.13-1.53, t= 2.34, p = 0.020). There was no significant difference in the X-direction setup error (p > 0.05). Therefore, the CTV-PTV margin values for a 3-mm gated window width in the X, Y, and Z directions are 5.51, 5.15, and 7.28 mm, respectively; those for a 4-mm gated window width in the X, Y, and Z directions are 5.52, 8.16, and 10.21 mm, respectively. The setup errors of the 3-mm - wide gating window are smaller than those of the 4-mm - wide gating window in the three dimensions. Therefore, when the patient's respiratory gating window width is reduced, the margin values of CTV-PTV can be reduced to increase the distance between the PTV and the organs at risk (OARs), which ensures adequate space for the dose to decrease, resulting in lower dose exposure to the OARs (heart, lungs, etc.), thus sparing the OARs from further damage. However, some patients with poor pulmonary function or unstable breathing amplitudes must be treated with a slightly larger gating window. Therefore, this study lays a theoretical basis for personalized precision radiotherapy, which can save time and reduce manpower in the delivery of clinical treatment to a certain extent. Another potential benefit of this work is to bring awareness to the potential implications of a slightly larger gating window during treatment without considering the resulting dosimetric impact.

nnFormer: Volumetric Medical Image Segmentation via a 3D Transformer.

Transformer, the model of choice for natural language processing, has drawn scant attention from the medical imaging community. Given the ability to exploit long-term dependencies, transformers are promising to help atypical convolutional neural networks to learn more contextualized visual representations. However, most of recently proposed transformer-based segmentation approaches simply treated transformers as assisted modules to help encode global context into convolutional representations. To address this issue, we introduce nnFormer (i.e., not-another transFormer), a 3D transformer for volumetric medical image segmentation. nnFormer not only exploits the combination of interleaved convolution and self-attention operations, but also introduces local and global volume-based self-attention mechanism to learn volume representations. Moreover, nnFormer proposes to use skip attention to replace the traditional concatenation/summation operations in skip connections in U-Net like architecture. Experiments show that nnFormer significantly outperforms previous transformer-based counterparts by large margins on three public datasets. Compared to nnUNet, the most widely recognized convnet-based 3D medical segmentation model, nnFormer produces significantly lower HD95 and is much more computationally efficient. Furthermore, we show that nnFormer and nnUNet are highly complementary to each other in model ensembling. Codes and models of nnFormer are available at https://git.io/JSf3i.

Bacterial Diversity Analysis and Screening for ACC Deaminase-Producing Strains in Moss-Covered Soil at Different Altitudes in Tianshan Mountains-A Case Study of Glacier No. 1.

The elevation of the snowline of the No. 1 Glacier in the Tianshan Mountains is increasing due to global warming, which has created favorable conditions for moss invasion and offers an opportunity to investigate the synergistic effects of incipient succession by mosses, plants, and soils. In this study, the concept of altitude distance was used instead of succession time. To investigate the changes of bacterial-community diversity in moss-covered soils during glacial degeneration, the relationship between bacterial community structure and environmental factors was analyzed and valuable microorganisms in moss-covered soils were explored. To do so, the determination of soil physicochemical properties, high-throughput sequencing, the screening of ACC-deaminase-producing bacteria, and the determination of ACC-deaminase activity of strains were performed on five moss-covered soils at different elevations. The results showed that the soil total potassium content, soil available phosphorus content, soil available potassium content, and soil organic-matter content of the AY3550 sample belt were significantly different compared with those of other sample belts (p < 0.05). Secondly, there was a significant difference (p < 0.05) in the ACE index or Chao1 index between the moss-covered-soil AY3550 sample-belt and the AY3750 sample-belt bacterial communities as the succession progressed. The results of PCA analysis, RDA analysis, and cluster analysis at the genus level showed that the community structure of the AY3550 sample belt and the other four sample belts differed greatly and could be divided into two successional stages. The enzyme activities of the 33 ACC-deaminase-producing bacteria isolated and purified from moss-covered soil at different altitudes ranged from 0.067 to 4.7375 U/mg, with strains DY1-3, DY1-4, and EY2-5 having the highest enzyme activities. All three strains were identified as Pseudomonas by morphology, physiology, biochemistry, and molecular biology. This study provides a basis for the changes in moss-covered soil microhabitats during glacial degradation under the synergistic effects of moss, soil, and microbial communities, as well as a theoretical basis for the excavation of valuable microorganisms under glacial moss-covered soils.

Supramolecular Strategy to Achieve Distinct Optical Characteristics and Boosted Chiroptical Enhancement Based on the Closed Conformation of Platinum(II) Complexes.

Synthesis of chiral molecules for understanding and revealing the expression, transfer, and amplification of chirality is beneficial to explore effective chiral medicines and high-performance chiroptical materials. Herein, we report a series of square-planar phosphorescent platinum(II) complexes adopting a dominantly closed conformation that exhibit efficient chiroptical transfer and enhancement due to the nonclassical intramolecular C-H···O or C-H···F hydrogen bonds between bipyridyl chelating and alkynyl auxiliary ligands as well as the intermolecular π-π stacking and metal-metal interactions. The spectroscopic and theoretical calculation results demonstrate that the chirality and optic properties are regulated from the molecular level to hierarchical assemblies. Notably, a 154 times larger gabs value of the circular dichroism signals is obtained. This study provides a feasible design principle to achieve large chiropticity and control the expression and transfer of the chirality.

Longitudinal Stability and Interrelations of Tonic and Phasic Irritability in Adolescent Girls.

Irritability is a transdiagnostic feature and a common mental health problem in adolescence. Prior studies indicate that irritability is composed of two correlated but separable dimensions, tonic irritability (i.e., irritable mood) and phasic irritability (i.e., temper outbursts), which are respectively associated with internalizing and externalizing outcomes. However, little is known about the stability and interrelations of tonic and phasic irritability. The current study examined the longitudinal interplay between tonic and phasic irritability during adolescence. A community sample of 544 girls (age 13.5-15.5 years) was assessed at 5 waves (over 3 years, in 9-month intervals). A random-intercept cross-lagged panel model was used to examine the within-person stability and longitudinal interrelations of tonic and phasic irritability. Pseudo-indicator models were used to help analyze all available data. Results suggest that tonic and phasic irritability had distinct patterns of development and co-development. Between individuals, tonic and phasic irritability showed moderate rank-order stability and high concurrent correlations. Within individuals, phasic irritability was found to positively predict both tonic and phasic irritability at the subsequent wave, whereas tonic irritability did not predict later phasic irritability and showed weaker within-person stability. These results suggest that increased or decreased phasic irritability in adolescent girls may signify continued increase or decrease in both tonic and phasic irritability. The study was among the first to demonstrate the discriminant validity of tonic and phasic irritability from a developmental perspective.

Revisiting reward impairments in schizophrenia spectrum disorders: a systematic review and meta-analysis for neuroimaging findings.

BACKGROUND: Abnormal reward functioning is central to anhedonia and amotivation symptoms of schizophrenia (SCZ). Reward processing encompasses a series of psychological components. This systematic review and meta-analysis examined the brain dysfunction related to reward processing of individuals with SCZ spectrum disorders and risks, covering multiple reward components. METHODS: After a systematic literature search, 37 neuroimaging studies were identified and divided into four groups based on their target psychology components (i.e. reward anticipation, reward consumption, reward learning, effort computation). Whole-brain Seed-based d Mapping (SDM) meta-analyses were conducted for all included studies and each component. RESULTS: The meta-analysis for all reward-related studies revealed reduced functional activation across the SCZ spectrum in the striatum, orbital frontal cortex, cingulate cortex, and cerebellar areas. Meanwhile, distinct abnormal patterns were found for reward anticipation (decreased activation of the cingulate cortex and striatum), reward consumption (decreased activation of cerebellum IV/V areas, insula and inferior frontal gyri), and reward learning processing (decreased activation of the striatum, thalamus, cerebellar Crus I, cingulate cortex, orbitofrontal cortex, and parietal and occipital areas). Lastly, our qualitative review suggested that decreased activation of the ventral striatum and anterior cingulate cortex was also involved in effort computation. CONCLUSIONS: These results provide deep insights on the component-based neuro-psychopathological mechanisms for anhedonia and amotivation symptoms of the SCZ spectrum.

[Comparative study on extraction of impacted mandibular wisdom teeth by Er:YAG laser and turbine handpiece].

PURPOSE: To compare the clinical effect of Er:YAG laser and turbine handpiece in the removal of lower horizontally impacted wisdom teeth, and to evaluate the operation time, postoperative pain, facial swelling, degree of mouth opening limitation and complications. METHODS: From March 2020 to May 2022, forty patients with bilateral lower mandibular horizontally impacted wisdom teeth in the Department of Oral and Maxillofacial Surgery of Linyi People's Hospital were selected，and all bilateral wisdom teeth were partially bone buried. The bilateral wisdom teeth of each patient were removed by Er:YAG laser on one side and turbine handpiece on the other side, respectively. The patients were divided into experimental(laser) group and control(turbine handpiece) group according to the ways of bone removal on each side. The clinical effect of the two groups was compared after a week of follow-up. Statistical analysis was performed with SPSS 19.0 software package. RESULTS: There was no significant difference between the two groups in operation time(P＞0.05). The incidence of postoperative pain, facial swelling, mouth opening limitation and complications in the experimental group were significantly lower than those in the control group(P＜0.05). CONCLUSIONS: The operation time of extraction with Er:YAG laser is similar to that with turbine handpiece, but laser can reduce postoperative reaction and the incidence of complications, which is easy to be accepted by patients and worthy of wide application.

Properties and metal binding behaviors of sediment dissolved organic matter (SDOM) in lakes with different trophic states along the Yangtze River Basin: A comparison and summary.

The nature of sediment dissolved organic matter (SDOM) can reflect the environmental background, nutritional status and human activities and is an important part of lakes. The differences in the binding capacity of heavy metals and organic matter in lake sediments with different trophic states at the catchment scale and the mechanism of the differences in binding are still unclear. To solve this problem, we collected bulk SDOMs (< 0.7 µm) from 6 respective lakes (from upstream to downstream) in the Yangtze River Basin (YRB) to qualitatively and quantitatively characterize their properties and metal binding behaviors using excitation-emission matrix spectroscopy combined with parallel factor analysis (EEM-FARAFAC) and two-dimensional correlation spectroscopy of synchronous fluorescence spectroscopy and Fourier transform infrared spectroscopy (2D-SF-COS and 2D-FTIR-COS). The results showed that sediment dissolved organic carbon (SDOC) was mainly enriched in low molecular weight (LMW: < 1 kDa) fractions. The total fluorescence intensity (Fmax) of SDOM from upstream was larger than that from downstream (p = 0.033), and humic-like fluorophores were dominant in these lakes. The Fmax of sediment humic-like components (C1+C2) was closely related to the trophic levels of the lakes. Protein-like substances and oxygen-containing functional groups (C-OH, C=O, and C-O) were preferred in the reaction between SDOM and copper (Cu2+) or cadmium (Cd2+), while a unique binding path was exhibited in the moderately eutrophic DCL. In terms of fluorophore types, higher Cu2+-binding abilities (LogKCu) were observed in the humic-like matter for the lakes in the upper reaches and tryptophan-like matter for the lakes from the midstream and downstream areas of the YRB. Although Cd2+ complexed only with humic-like matter, LogKCd was higher than LogKCu. In terms of molecular weight (MW), the LogKCu/Cd of components were enhanced after MW fractionation. The HMW (0.7 µm - 1 kDa) components possessed higher LogKCu in most lakes (except for CHL and C4). The different fluorophores and molecular weight fractions in SDOM make an important contribution to reducing the ecological risks of heavy metals in lakes.

Novel deep learning-based computer-aided diagnosis system for predicting inflammatory activity in ulcerative colitis.

BACKGROUND AND AIMS: Endoscopy is increasingly performed for evaluating patients with ulcerative colitis (UC). However, its diagnostic accuracy is largely affected by the subjectivity of endoscopists' experience and scoring methods, and scoring of selected endoscopic images cannot reflect the inflammation of the entire intestine. We aimed to develop an automatic scoring system using deep-learning technology for consistent and objective scoring of endoscopic images and full-length endoscopic videos of patients with UC. METHODS: We collected 5875 endoscopic images and 20 full-length videos from 332 patients with UC who underwent colonoscopy between January 2017 and March 2021. We trained the artificial intelligence (AI) scoring system using these images, which was then used for full-length video scoring. To more accurately assess and visualize the full-length intestinal inflammation, we divided the large intestine into a fixed number of "areas" (cecum, 20; transverse colon, 20; descending colon, 20; sigmoid colon, 15; rectum, 10). The scoring system automatically scored inflammatory severity of 85 areas from every video and generated a visualized result of full-length intestinal inflammatory activity. RESULTS: Compared with endoscopist scoring, the trained convolutional neural network achieved 86.54% accuracy in the Mayo-scored task, whereas the kappa coefficient was .813 (95% confidence interval [CI], .782-.844). The metrics of the Ulcerative Colitis Endoscopic Index of Severity-scored task were encouraging, with accuracies of 90.7%, 84.6%, and 77.7% and kappa coefficients of .822 (95% CI, .788-.855), .784 (95% CI, .744-.823), and .702 (95% CI, .612-.793) for vascular pattern, erosions and ulcers, and bleeding, respectively. The AI scoring system predicted each bowel segment's score and displayed distribution of inflammatory activity in the entire large intestine using a 2-dimensional colorized image. CONCLUSIONS: We established a novel deep learning-based scoring system to evaluate endoscopic images from patients with UC, which can also accurately describe the severity and distribution of inflammatory activity through full-length intestinal endoscopic videos.

Acid-mediated phase transition synthesis of stable nanocrystals for high-power LED backlights.

Perovskite nanocrystals (PNCs) have excellent optical and optoelectronic properties, but their intrinsic instability hampers their practical applications. Herein, stable CsPbBr3 nanocrystals (NCs) are fabricated with triethylaluminium (TMA, a Lewis acid) and hydrobromic acid by the co-assisted transformation of Cs4PbBr6 NCs. TMA forms a cross-linked alumina (AlOx) encapsulation layer on the nanocrystal surface to suppress the deformation and ion migration. The introduction of hydrobromic acid acts as a binding ligand, and the acidified reaction environment provides conditions for the water-triggered phase transformation of Cs4PbBr6 NCs into CsPbBr3 NCs. The synergistic effect of TMA and hydrobromic acid improves the stability of CsPbBr3 NCs. The obtained CsPbBr3 NC film maintains a high photoluminescence (PL) intensity after immersion in water. When stored in the atmosphere for over 30 days, the PL intensity of the CsPbBr3 NC film hardly decreases. The proposed acid co-assisted phase transformation strategy provides a new avenue for the stabilization of PNCs which exhibits wider application prospects in backlight displays.

Assessment and source analysis of heavy metal contamination in water and surface sediment in Dongping Lake, China.

Dongping Lake is the only natural lake in the lower Yellow River and an important hub of South-North Water Diversion Project, its water quality is of vital importance to the environmental protection and the security of water supply. To assess the heavy metal (HM) contamination in Dongping Lake, samples in water and surface sediment were taken from 59 sampling sites over the entire lake. The statistical characteristics, pollution conditions, and source identifications were analyzed using coupling methods of entropy water quality index (EWQI), modified pollution index (mCd), enrichment coefficient (EF), geo-accumulation index (Igeo), potential ecological risk index (PERI), and positive matrix factorization (PMF). In present study, the averaged concentrations of all studied HMs in water body of Dongping Lake were below the limit of drinking water quality standard recommended by WHO, and the EWQI and mCd of HM concentrations were identified to be in good and excellent conditions. The concentrations of almost all studied HMs in surface sediment of Dongping Lake exceeded the background values in the soil of Shandong Province, and Cd (cadmium) was the dominant pollutant. With EF > 2, Igeo > 1, and Er > 80, Cd in sediment was under moderate pollution. The outcomes of source analysis revealed that the HMs in surface sediment were mainly derived from the primary and secondary industries. Specifically, manufacturing industries contributed the most to the HM contaminations in sediment of Dongping Lake.

Multi-spectroscopic investigation of the molecular weight distribution and copper binding ability of dissolved organic matter in Dongping Lake, China.

The properties and metal-binding abilities of dissolved organic matter (DOM) rely on its molecular weight (MW) structure. In this study, the spatial differences of DOM in compositions, MW structures, and binding mechanisms with copper (Cu2+) in Dongping Lake were investigated by applying excitation-emission matrix combining parallel factor analysis (EEM-PARAFAC), synchronous fluorescence (SF) spectra, two-dimensional correlation spectra (2D-COS), and Fourier transform infrared (FTIR) spectra. The EDOM for the entrance of the Dawen River and PDOM for the macrophyte-dominated region were divided from DOM of Dongping Lake based on hierarchical clustering analysis (HCA) and principal component analysis (PCA) and were size-fractioned into MW < 500 kDa and <100 kDa fractions. According to EEM-PARAFAC, Dongping Lake was dominated by tryptophan-like substances with MW < 500 kDa. The concentration of PDOM was higher than that of EDOM (p < 0.05). 2D-COS showed that protein-like components preceded humic-like components binding to Cu2+ regardless of sample type (215 nm > 285 nm > 310-360 nm). The Cu2+ binding capacity of DOM exhibited specific differences in space, components, and molecular weights. The humic-like component 1 (C1) and tryptophan-like component 4 (C4) of PDOM showed stronger binding abilities than those of EDOM. Endogenous tryptophan-like component 4 (C4) had a higher binding affinity for Cu2+ than humic-like components (logKa: C4 > C1 > C2) in PDOM irrespective of MW. Humic-like components with MW < 500 kDa displayed higher binding potentials for Cu2+. FTIR spectra showed that the main participants of DOM-Cu complexation included aromatic hydrocarbons, aliphatic groups, amide Ⅰ bands, and carboxyl functional groups. This study provides spatial-scale insights into the molecular weight structure of DOM in influencing the behavior, fate, and bioavailability of heavy metals in lakes.

Perspectives of metal-organic framework nanosystem to overcome tumor drug resistance.

Cancer is one of the most harmful diseases in the world, which causes huge numbers of deaths every year. Many drugs have been developed to treat tumors. However, drug resistance usually develops after a period of time, which greatly weakens the therapeutic effect. Tumor drug resistance is characterized by blocking the action of anticancer drugs, resisting apoptosis and DNA repair, and evading immune recognition. To tackle tumor drug resistance, many engineered drug delivery systems (DDS) have been developed. Metal-organic frameworks (MOFs) are one kind of emerging and promising nanocarriers for DDS with high surface area and abundant active sites that make the functionalization simpler and more efficient. These features enable MOFs to achieve advantages easily towards other materials. In this review, we highlight the main mechanisms of tumor drug resistance and the characteristics of MOFs. The applications and opportunities of MOF-based DDS to overcome tumor drug resistance are also discussed, shedding light on the future development of MOFs to address tumor drug resistance.

Physicochemical properties and greenhouse gas emissions of water body during the decomposition of Potamogeton crispus with different values of initial debris biomass.

A sediment-water mesocosm experiment was set up to identify the effects of different debris biomass P. crispus decomposition on water body physicochemical properties and greenhouse gas emissions in Dongping Lake, a typical shallow macrophytic lake in the north of China. The results indicated that the decomposition of high biomass (BL-2) of P. crispus could significantly affect the physicochemical properties of water bodies, especially within the first 47 days. During the experiment, DO and water pH in BL-2 were significantly lower, while NH3-N, NO2--N, DOC, and DRP in surface water and OM in sediment were significantly higher than those in the low biomass treatment (BL-1) and zero control (CK). Moreover, the DOC in BL-1 were significantly higher than CK. The decomposition of P. crispus significantly affected the emission fluxes of CH4 and CO2, but had no significant impact on N2O emission. CH4 and CO2 fluxes were generally more significantly correlated with the properties of surface water in BL-2 than in BL-1. High debris biomass decomposition significantly promoted the emission of CH4 enhancing the source effect of water body, while the decomposition of both low and high biomass notably promoted the emission of CO2 converting the water bodies from sink to source of CO2. There were significant differences in global warming potential among the three groups in which CH4 contributed most. Considering the negative impact on water environment and elevated carbon emission during the decomposition of P. crispus, it was suggested to strengthen the management of P. crispus in Dongping Lake.