Precise segmentation of non-enhanced computed tomography in patients with ischemic stroke based on multi-scale U-Net deep network model.

BACKGROUND AND OBJECTIVE: Acute ischemic stroke requires timely diagnosis and thrombolytic therapy, but it is difficult to locate and quantify the lesion site manually. The purpose of this study was to explore a more rapid and effective method for automatic image segmentation of acute ischemic stroke. METHODS: The image features of 30 stroke patients were segmented from non-enhanced computed tomography (CT) images using a multi-scale U-Net deep network model. The Dice loss function training model was used to counter the similar imbalance problem in the data. The difference was compared between manual segmentation and automatic segmentation. RESULTS: The Dice similarity coefficient based on multi-scale convolution U-Net network segmentation was 0.86±0.04, higher than the Dice based on classic U-Net (0.81±0.07, P=0.001). The lesion contour of automatic segmentation based on multi-scale U-Net was very close to manual segmentation. The error of lesion area is 1.28±0.59 mm2, and the Pearson correlation coefficient was r=0.986 (P<0.01). The motion time of automatic segmentation is less than 20 ms. CONCLUSIONS: Multi-scale U-Net deep network model can effectively segment ischemic stroke lesions in non-enhanced CT and meet real-time clinical requirements.

An aggregation-induced emission fluorogen/DNA probe carrying an endosome escaping pass for tracking reduced thiol compounds in cells.

The fluorescent nanoprobes for reduced thiol compounds (represented by glutathione, GSH) are constructed based on the aggregation-induced emission (AIE) luminescence mechanism and endosome escape technology. First, a DNA sequence was designed with the decoration of biotin at the 5'-end, disulfide bound in the internal portion, and amino at the 3'-end. The aptamer of the MCF-7 cell was also one of the most important structures in our DNA sequence for the selectivity of MCF-7 cells. We modified streptavidin-modified magnetic beads (MB) with biotin-modified influenza virus hemagglutinin peptide (HA) and biotin-DNA-amino to form MB/DNA/HA. Carboxyl-modified tetraphenylethylene (TPE), an iconic AIE fluorogen, was bonded with amino-modified DNA by covalent interactions (TPE/DNA). Then, the TPE molecule was attached on the outer layer of MB via biotin-modified TPE/DNA to form MB/DNA/HA/TPE. Compared with traditional AIE/biomolecule conjugates, the nanoprobe had an enhanced endosome escape function, due to the assembly of HA. This construction made the intracellular fluorescence response more accurate. In the presence of reduced thiol compounds (take GSH, for example), the disulfide bond on the DNA was reduced by thiol-disulfide exchange reactions and the TPE molecule was released into the solution. The shedding TPE molecule was more hydrophobic than TPE/DNA and the conversion of TPE/DNA to shedding TPE could lead to the aggregation of the TPE fluorogen. Thus, its fluorescence was enhanced. Under the optimized condition, the fluorescence intensity increased with the increase in concentration of GSH' ranging from 1.0 × 10-9 M to 1.0 × 10-5 M' and the detection limit was 1.0 × 10-9 M. The relative standard deviation (RSD) was calculated to be 3.6%. The recovery in cell homogenate was from 94.5 to 102.7%. The nanoprobe provided a way for the detection of reduced thiol compounds in MCF-7 cells. We envision that, in the near future, our strategy of DNA-instructed AIE could be widely applied for biosensing and bioimaging in vitro and even in vivo with dramatically enhanced sensitivity. Graphical Abstract.

Activated Plasmonic Nanoaggregates for Dark-Field in Situ Imaging for HER2 Protein Imaging on Cell Surfaces.

Dark-field microscopy (DFM) based on localized surface plasmon resonance (LSPR) was used for observation of experimental phenomena, which is a hopeful nondamaging and non-photobleaching biological imaging technique. In this strategy, plasma nanoaggregates with stronger scattering efficiency were formed in the presence of the target, causing a "turn-on" phenomenon, when asymmetry modified AuNPs were introduced as probes with zero LSPR background. First, Au1-N3 probe and Au2-C≡C probe were designed for the cycloaddition between azide and alkyne to form AuNP dimers under catalytic action by Cu+, which was obtained from the reduction of Cu2+ by sodium ascorbate. The two kinds of probes were successfully used for the detection of Cu2+ in rat serum. Then, to apply this concept to protein on cells, DNA and antibody were modified on the probes. DNA1/Au1-N3 probe and anti-HER2/Au2-C≡C probe were proposed for HER2 protein DFM on cells. By designing an aptamer sequence in primer, the rolling circle amplification (RCA) was introduced in HER2 DFM on cells, and the image signal was much brighter than that from no-RCA. The unique design made it easier to discriminate the target signal from background noise in cell DFM. This method might be used in the fields of molecular diagnostics and cell imaging.

Occurrence of pharmaceuticals and personal care products, and their associated environmental risks in a large shallow lake in north China.

Eighteen selected pharmaceuticals and personal care products (PPCPs), consisting of five non-antibiotic pharmaceuticals (N-APs), four sulfonamides (SAs), four tetracyclines (TCs), four macrolides (MCs), and one quinolone (QN) were detected in water, pore water, and sediment samples from Baiyangdian Lake, China. A total of 31 water samples and 29 sediment samples were collected in March 2017. Caffeine was detected with 100% frequency in surface water, pore water, and sediment samples. Carbamazepine was detected with 100% frequency in surface water and sediment samples. Five N-APs were prominent, with mean concentrations of 4.90-266.24 ng/l in surface water and 5.07-14.73 µg/kg in sediment samples. Four MCs were prominent, with mean concentrations of 0.97-29.92 ng/l in pore water samples. The total concentrations of the different classes of PPCPs followed the order: N-APs (53.26%) > MCs (25.39) > SAs (10.06%) > TCs (7.64%) > QNs (3.64%) in surface water; N-APs (42.70%) > MCs (25.43%) > TCs (14.69%) > SAs (13.90%) > QNs (3.24%) in sediment samples, and MCs (42.12%) > N-APs (34.80%) > SAs (11.71%) > TCs (7.48%) > QNs (3.88%) in pore water samples. The geographical differences of PPCP concentrations were largely due to anthropogenic activities. Sewage discharged from Baoding City and human activities around Baiyangdian Lake were the main sources of PPCPs in the lake. An environmental risk assessment for the upper quartile concentration was undertaken using calculated risk quotients and indicated a low or medium-high risk from 18 PPCPs in Baiyangdian Lake and its five upstream rivers.

Occurrence of pharmaceuticals and personal care products, and their associated environmental risks in Guanting Reservoir and its upstream rivers in north China.

Eighteen selected pharmaceuticals and personal care products (PPCPs), consisting of five non-antibiotic pharmaceuticals (N-APs), four sulfonamides (SAs), four tetracyclines (TCs), four macrolides (MCs), and one quinolone (QN) were detected in surface water and sediments from Guanting Reservoir (GTR) and its upstream rivers in north China. Acetaminophen, caffeine, chlorotetracycline, and ofloxacin were detected with 100% frequency in the surface water of GTR and its upstream rivers, while diltiazem was also detected with 100% frequency in surface water from the reservoir's upstream rivers. Acetaminophen and caffeine were detected with 100% frequency in sediments from GTR and its upstream rivers, while high concentrations of ofloxacin in GTR, and carbamazepine, tetracycline, and chlortetracycline in upstream rivers were also detected in 100% of samples. Five N-APs, especially acetaminophen and caffeine, were prominent pollutants. The mean concentrations of acetaminophen were 155 and 302 ng L-1 in surface water and 529 and 202 ng g-1 in sediments from GTR and upstream rivers, respectively. The mean concentrations of caffeine were 208 and 338 ng L-1 in surface water samples and 1430 and 1020 ng g-1 in sediments from GTR and upstream rivers, respectively. The geographical differences in PPCP concentrations were largely due to anthropogenic activities. Sewage discharged from Zhangjiakou City and human activities around the GTR basin were the main sources of PPCPs in this area. An environmental risk assessment for the worst-case scenario was undertaken using calculated risk quotients, which indicated a medium risk from erythromycin in GTR and a high risk in its upstream rivers.

[Potential Risk and Distribution Characteristics of PPCPs in Surface Water and Sediment from Rivers and Lakes in Beijing, China].

Thirty-four water samples and twenty-three sediment samples from the urban rivers, ten water samples and five sediment samples from urban lakes were collected in Beijing. Ten PPCPs (acetaminophen, lincomycin, caffeine, trimethoprim, azithromycin, sulfamethoxazole, diltiazem, tylosin, carbamazepine, fluoxetine) were extracted from water samples by solid-phase extraction (SPE) and from sediment samples by ultrasonic extraction, and then analyzed by high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). The ranges of geometric mean values were 0-655 ng·L-1 and 0-252 ng·L-1 in water samples from urban rivers and lakes,respectively. The range of detection ratio was 0-100% for 10 PPCPs in river water samples, caffeine was the dominant pollutant in water samples and the detection ratio was 100%, whereas sulfamethoxazole, diltiazem and tylosin were not detected in river samples. The range of detection ratio was 0-100% for 10 PPCPs in lake water samples. The detection ratios of acetaminophen, lincomycin, caffeine and azithromycin were 100%, whereas sulfamethoxazole, diltiazem, tylosin, carbamazepine were not detected in lake water samples. The ranges of geometric mean values were N.D.-1709 ng·g-1and N.D.-35.9 ng·g-1in sediment samples from urban rivers and lakes, respectively. The ranges of detection ratio were 4%-96% and 0-100% for 10 PPCPs in river and lake sediment samples, respectively. The detection ratio of trimethoprim was 96% and that of tylosin was 4% in river sediment, the detection ratio of diltiazem was 100% and caffeine, tylosin,carbamazepine were not detected. The concentrations of PPCPs in water and sediment samples from Yongyin River, Liangshui River, Tonghui River, Bahe River were higher than those in other rivers. The concentrations of PPCPs in water and sediment samples from Yongding River,Kunyu River were lower than those in other rivers. Further risk assessment results showed that the overall risk was not high in water of rivers and lakes and the RQ values were below 0.1, which showed low risk to microorganisms. But the condition was not the same in sediment from rivers and lakes. The RQ values of acetaminophen were between 0.1 and 1 in sediments from Yongyin River, Tonghui River, Bahe River. The RQ values of lincomycin were between 0.1 and 1 in sediments from Yongyin River, Wenyu River,Tonghui River, Hucheng River, Bahe River, Liangshui River, Houhai Lake. The RQ values of trimethoprim were between 0.1 and 1 in sediments from Yongyin River, Qinghe River, Wenyu River, Tonghui River Hucheng River, Bahe River, Liangma River, Liangshui River and Houhai Lake. The RQ values of azithromycin were between 0.1 and 1 in sediments from Liangma River, Liangshui River, which all showed medium risk to microorganisms in sediments. The RQ values of azithromycin exceeded 1 from Yongyin River, Qinghe River, Wenyu River, Tonghui River, Bahe River and Houhai Lake, which showed high risk to microorganisms in sediments.

[Pollution Characteristics of Chlorobenzenes in Organs of Fish from Typical Epidemic Areas of Schistosomiasis Prevalence].

Sixty-eight fish samples were collected from typical epidemic areas of schistosomiasis prevalence. The contents of 12 CB congeners in fish samples were measured using GC/MS technique. The results indicated that 1,3-DIC, 1,4-DIC, 1,2-DIC and HCB were the most predominant CB congeners in the samples from the studying area. The source of HCB was PCP (pentachlorophenol), which was used to control the schistosomiasis prevalence, used in study area. And DIC came from the degradation of HCB and the articles of daily use. The geometric average of CBs in muscle ranged from 2731.50 to 7811.23 ng·g-1 lipid weight, while the summarized concentration of CBs in fish gonads, brains, kidneys, livers ranged from 2557.89 to 4640.05 ng·g-1 lipid weight, 2423.18 to 3329.61 ng·g-1 lipid weight, 1628.05 to 4667.76 ng·g-1 lipid weight and 704.92 to 1086.96 ng·g-1 lipid weight, respectively. When compared to other studies in China and other countries, the concentrations of CBs in these fish samples were at a relatively high level.

[Spatial, Temporal Distribution Characteristics and Potential Risk of PPCPs in Surface Sediments from Taihu Lake].

Fourteen sediment samples from 15 river estuaries and six sediments from 6 drinking water resource were collected from Taihu Lake. Nine pharmaceutical and personal care products(PPCPs) in the sediments samples were measured by using the HPLC-MS/MS technique. The ranges of geometric mean values were 1.60-129 ng·g-1 and 1.36-22.0 ng·g-1, respectively. Caffeine was the dominant pollutant in fourteen sediments near the river estuary, the content of which covered 52% of amounts of 9 PPCPs. Lincomycin, trimethoprime, azithromycin, sulfamethoxazole and tylosin were the dominant pollutants in six sediments near the drinking water resource, the contents of which covered 79% of amounts 9 PPCPs. From the point of spatial distribution, the results of PPCPs in Zhushan bay and East of Yixing in the northwest and west of Taihu Lake showed higher concentration than those in other sample sites. From the composition, the origin of PPCPs was different. Municipal sewage, stock farming and aquaculture were the main sources of PPCPs in Taihu Lake. Pharmaceuticals of human use showed the dominant pollution in fourteen sediments near the river estuary and drugs of veterinary use showed the dominant pollution in six sediments near the water resource. The concentrations of PPCPs in fourteen sediments of river mouth showed high level. It suggested that PPCPs pollutants were discharged to Taihu Lake continuously. Further risk assessment results showed that the overall risk was not high except for some PPCPs compounds. The RQ exceeded 1 for acetaminophen, azithromycin and sulfamethoxazole in the surface sediments of 15 river estuaries and 6 water resources, which showed high risk. The RQ was between 0.01 to 0.1 for carbazepine in the surface sediments of 15 river estuaries and 6 water resources, which showed medium risk. The RQ was below 0.01 for caffeine, lincomycin, trimethoprim, diltiazem and tylosin in the sediments of 15 river estuaries and 6 water resources, which showed low risk.

Tris-(nitrato-κ(2)O,O')bis[4,4,5,5-tetra-methyl-2-(pyridin-2-yl-κN)imidazoline-1-oxyl 3-oxide-κO]holmium(III).

In the title compound, [Ho(NO(3))(3)(C(12)H(16)N(3)O(2))(2)], the Ho(III) ion is ten-coordinated in a distorted bicapped square-anti-prismatic environment by two N,O-bidentate nitronyl nitroxide radical ligands and three O,O'-bidentate nitrate anions. Complex mol-ecules are connected by C-H⋯O hydrogen bonds into a three-dimensional network.

Bis[4,4,5,5-tetra-methyl-2-(pyridin-2-yl-κ(2)N)imidazoline-1-oxyl 3-oxide-κO]tris-(nitrato-κ(2)O,O')terbium(III).

The title compound, [Tb(NO(3))(3)(C(12)H(16)N(3)O(2))(2)], was prepared from the nitroxide radical ligand 4,4,5,5-tetra-methyl--2-(pyridin-2-yl)-imidazoline-1-oxyl-3-oxide and Tb(III) nitrate. The Tb(III) ion adopts a doubly-capped square-anti-prismatic coord-ination environment defined by three chelating nitrate anions and two N,O-bidentate nitronyl nitroxide radical ligands. Weak C-H⋯O hydrogen bonds connect the molecules into a three-dimensional framework. The title structure is isotypic with the Ho analogue [Li (2012 ▶). Acta Cryst. E68, 550].