Hydrogen-Bonded Organic Cocrystal-Encapsulated Perovskite Nanocrystals as Coreactant-Free Electrochemiluminescent Luminophore for the Detection of Uranium.

Lead halide perovskite nanocrystals with excellent photophysical properties are promising electrochemiluminescence (ECL) candidates, but their poor stability greatly restricts ECL applications. Herein, hydrogen-bonded cocrystal-encapsulated CsPbBr3 perovskite nanocrystals (PeNCs@NHS-M) were synthesized by using PeNCs as nuclei for inducing the crystallization of melamine (M) and N-hydroxysuccinimide (NHS). The as-synthesized composite exhibits multiplicative ECL efficiencies (up to 24-fold that of PeNCs) without exogenous coreactants and with excellent stability in the aqueous phase. The enhanced stability can be attributed to the well-designed heterostructure of the PeNCs@NHS-M composite, which benefits from both moiety passivation and protection of the peripheral cocrystal matrix. Moreover, the heterostructure with covalent linkage facilitates charge transfer between PeNCs and NHS-M cocrystals, realizing effective ECL emission. Meanwhile, the NHS and M components act as coreactants for PeNCs, shortening the electron-transport distance and resulting in a significant increase in the ECL signal. Furthermore, by taking advantage of the specific binding effect between NHS-M and uranyl (UO22+), an ECL system with both a low detection limit (1 nM) and high selectivity for monitoring UO22+ in mining wastewater is established. The presence of UO22+ disrupted the charge-transfer effect within PeNCs@NHS-M, weakening the ECL signals. This work provides an efficient design strategy for obtaining stable and efficient ECLs from perovskite nanocrystals, offering a new perspective for the discovery and application of perovskite-based ECL systems.

Hydrogen-Bonded Cocrystals Encapsulating CsPbBr3 Perovskite Nanocrystals with Enhancement of Charge Transport for Photocatalytic Reduction of Uranium.

At present, poor stability and carrier transfer efficiency are the main problems that limit the development of perovskite-based photoelectric technologies. In this work, hydrogen-bonded cocrystal-coated perovskite composite (PeNCs@NHS-M) is easily obtained by inducing rapid crystallization of melamine (M) and N-hydroxysuccinimide (NHS) with PeNCs as the nuclei. The outer NHS-M cocrystal passivates the undercoordinated lead atoms by forming covalent bonds, thereby greatly reducing the trap density while maintaining good structure stability for perovskite nanocrystals. Moreover, benefiting from the interfacial covalent band linkage and long-range ordered structures of cocrystals, the charge transfer efficiency is effectively enhanced and PeNCs@NHS-M displays superior photoelectric performance. Based on the excellent photoelectric performance and abundant active sites of PeNCs@NHS-M, photocatalytic reduction of uranium is realized. PeNCs@NHS-M exhibits U(VI) reduction removal capability of up to 810.1 mg g-1 in the presence of light. The strategy of cocrystals trapping perovskite nanocrystals provides a simple synthesis method for composites and opens up a new idea for simultaneously improving the stability and photovoltaic performance of perovskite.

Construction of a Bifunctional Redox-Site Conjugated Covalent-Organic Framework for Photoinduced Precision Trapping of Uranyl Ions.

The performance of covalent-organic frameworks (COFs) for the photocatalytic extraction of uranium is greatly limited by the number of adsorption sites. Herein, inspired by electronegative redox reactions, we designed a nitrogen-oxygen rich pyrazine connected COF (TQY-COF) with multiple redox sites as a platform for extracting uranium via combining superaffinity and enhanced photoinduction. The preorganized bisnitrogen-bisoxygen donor configuration on TQY-COF is entirely matched with the typical geometric coordination of hexavalent uranyl ions, which demonstrates high affinity (tetra-coordination). In addition, the presence of the carbonyl group and pyrazine ring effectively stores and controls electron flow, which efficaciously facilitates the separation of e-/h+ and enhances photocatalytic performance. The experimental results show that TQY-COF removes up to 99.8% of uranyl ions from actual uranium mine wastewater under the light conditions without a sacrificial agent, and the separation coefficient reaches 1.73 × 106 mL g-1 in the presence of multiple metal ions, which realizes the precise separation in the complex environment. Importantly, DFT calculations further elucidate the coordination mechanism of uranium and demonstrate the necessity of the presence of N/O atoms in the photocatalytic adsorption of uranium.

3D Ionic Olefin-Linked Conjugated Microporous Polymers for Selective Detection and Removal of TcO4-/ReO4- from Wastewater.

Technetium (99Tc) is a highly toxic radioactive nuclear wastewater contaminant. Real-time detection of 99Tc is very difficult due to its difficult-to-complex nature. Herein, a novel three-dimensional ionic olefin-linked conjugated microporous polymer (TFPM-EP-Br) is constructed using tetrakis(4-aldehyde phenyl)methane (TFPM) as the central monomer. The unique cationic cavity and highly hydrophobic framework enable TFPM-EP-Br to act as a fluorescent sensor for TcO4-. The fluorophores of TFPM-EP-Br can be quenched due to electron transfer from TFPM-EP-Br to TcO4- and the formation of strongly nonfluorescent complexes. Meanwhile, the regular pore channels are beneficial for the fast mass transfer of TcO4-, resulting in an ultrafast response time (less than 2 s) with an ultralow detection limit (33.3 nM). In addition, the ultrahigh specific surface area enables TFPM-EP-Br to combine the ability to synergistically detect and remove radioactive 99Tc. From this perspective, the novel conjugated microporous polymer has made a breakthrough in the detection and extraction of radioactive contaminants.

Delayed active bleeding after radical evacuation of injected polyacrylamide hydrogel and immediate implant based breast reconstruction.

BACKGROUND: Polyacrylamide hydrogel (PAAG) was used in breast augmentation surgery in China during 1997-2006. Its application has led to increasing complications such as localized lumps, asymmetry, diffuse stiffness, infections, and localized tenderness or myalgia. Hence, many patients have sought for surgical gel evacuation in the following years. CASE PRESENTATION: A 37-year-old G2P0A2 slim (BMI = 18.3) woman who had received injected PAAG bilateral breast augmentation in China 15 years ago, visited our hospital for gel removal due to left upper quadrant breast tenderness with burning sensation. We performed simple mastectomy and immediate breast augmentation with silicone prostheses. Her postoperative course was uneventful. However, subcutaneous hematoma formed right after she started breast massage on the day 14 post operatively. The patient promptly received a CT-guided drainage followed by exploratory surgery with coagulation of the lesion located at the second intercostal space 2 cm to the right of the sternum. DISCUSSION: Delayed bleeding in our patient might be contributed to below reasons. First, the usage of PAAG might cause degeneration of muscle tissue structure which made it more fragile than normal muscle tissue. Secondly, the lack of sufficient coverage, cushion and protection of the muscle tissue in slim patient in addition to the external compression and shearing force of massage. CONCLUSION: In slim patients, we suggest that the postoperative breast massage should be postponed for months until the tissue is recovered, or delayed breast reconstruction could also be considered.

[Sequence analysis of Bt insertion flanking fragments in transgenic Bt cotton].

The copies of outside gene and DNA structure of integration locus are important in high expression and avoidance of gene silence. Many research results showed that outside genes were inserted into the plant genome with recombinant type, and the integration was related to border T-DNA sequence in the course of Agrobaterium mediated transformation. SAR structure was also found in the integration location of transformants with direct DNA transformation method. The pollen-tube pathway transformation, one of direct DNA transformation method, was very successfully used in Bt transgenic cotton in China. But until now there has been no report about Bt gene integration. The aim of this research was to investigate flanking DNA structure in order to explain the mechanism of direct transformation method in the future. The structure of flanking DNA fragments of Bt integration in four different transgenic Bt cotton varieties including Simian-3, 161 resistant breeding line, 161 sensitive breeding line and Guokangmian-1 was analyzed with TAIL-PCR and nested PCR. The flanking DNA sequences of different self-crossed progenies from one plant are the same. In contrary, their DNA sequences are diverse for different breeding lines. Upstream flanking fragments in some transgenic cotton contained short transformation plasmid sequences, downstream flanking fragments in all the transgenic cotton varieties were composed of high percentage AT. The percentage of AT in Simian-3 transgenic Bt variety was as high as 92%. All the flanking fragments were of multi-copies and similar to repetitive sequences. No recognition sites of TOP enzyme were found in these fragments.

Recurrent upper quadrant pain: a fish bone secondary to gastric perforation and liver abscess.

A 60-year-old male patient was admitted to our hospital for recurrent upper quadrant pain for 1 month. He had a past history of coronary artery disease. After admission, he repeatedly suffered from high-grade fever, chills and upper quadrant pain. Computed tomography (CT) showed a round hypodense mass in the left lobe of the liver, approximately 2.7 × 2.2 cm in size, and a fish bone was confirmed by surgery in the left lobe of liver. The patient was cured completely after surgical removal of the fish bone and liver abscess. CT scan 1 month after discharge showed that the liver abscess had disappeared completely.

[Expression of lung resistance protein and multidrug resistance protein genes in bone marrow cells of acute leukemia patients and its clinical significance].

To study the expression of lung resistance protein (LRP) and multidrug resistance protein (MRP) genes in bone marrow cells in patients with acute leukemia and its clinical significance, expression of LRP and MRP mRNA in bone marrow cells from 47 cases of acute leukemia, including 10 refractory or relapsed cases, and 7 normal individuals were determined by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). The result s showed that expression of LRP gene was negative in normal individuals. LRP mRNA level in newly treated cases of acute myelocytic leukemia and refractory or relapsed cases was significantly higher than that in normal individuals, increased LRP mRNA level has correlation with lower sensitivity to initial chemotherapy and was associated with reduced overall survival rate. Complete remission (CR) rate in LRP positive patients was lower than that in negative cases. The level of LRP expression was correlated with that of MRP mRNA. In conclusion, the expression of LRP mRNA can predict the treatment outcome and prognosis for acute myelocytic leukemia, prognosis was even worse in LRP and MRP linked expression cases, therefore, LRP was an important resistant factor, determination of LRP and MRP expression can help us to evaluate the prognosis and choose chemotherapy program.

[Expression of nm23-H(1) mRNA in Bone Marrow Cells from Patients with Myelodysplastic Syndrome and Its Clinical Implication]

The purpose of this investigation was to explore the expression of nm23-H(1) gene in patients with myelodysplastic syndrome (MDS) and evaluate the relationship between nm23-H(1) expression and therapeutic outcomes. Semi-quantitative RT-PCR was used to detect the expression of nm23-H(1) mRNA in marrow mononuclear cells from 28 MDS patients and 15 normal subjects. nm23-H(1)/GAPDH ratio >/= 0.5 was believed to a positive case. The expression of nm23-H(1) was positive in 24 of 28 MDS patients, and the average level was 0.89 +/- 0.56. nm23-H(1) mRNA was negative in normal controls. The overexpression of nm23-H(1) mRNA in MDS patients could predict outcome of treatment and prognosis for MDR patients.