Highly sensitive and selective fluorescent "turn-on" sensor for Ag+ detection using MAPbBr3@PCN-221(Fe): An efficient Ag+-bridged energy transfer from perovskite to MOF.

Metal ion-induced water pollution is attracting increasing public attention. Perovskite quantum dots and metal-organic frameworks (MOFs), owing to their outstanding properties, hold promise as ideal probes for detecting metal ions. In this study, a composite material, MAPbBr3@PCN-221(Fe), was prepared by encapsulating MAPbBr3 quantum dots with PCN-221(Fe), demonstrating high chemical stability and good reusability. The composite material shows a sensitive fluorescence turn-on signal in the presence of silver ions. The fluorescence intensity of the composite material exhibits a linear relationship with the concentration of Ag+ in the solution, with a low detection limit of 8.68 µM. Moreover, the fluorescence signal exhibits a strong selectivity for Ag+, enabling the detection of Ag+ concentration. This fluorescence turn-on signal originates from the Ag+-bridged energy transfer from the conductive band of MAPbBr3 to the excited state of the MOF, which is directly proportional to the concentration of silver ions. Simultaneously, this finding may open up a new possibility in artificial controlled energy transfer from perovskite to MOF for future development.

Water-stable perovskite CsPb2Br5/CdSe quantum dot-based photoelectrochemical sensors for the sensitive determination of dopamine.

A heterojunction of CdSe quantum dots in situ grown on the perovskite CsPb2Br5 (CsPb2Br5/CdSe) for water-stable photoelectrochemical (PEC) sensing was simply synthesized using the hot-injection method. Due to the inherent built-in electric field and the matching band structure between CsPb2Br5 and CdSe, the CsPb2Br5/CdSe p-n heterojunction demonstrates enhanced photoelectrochemical properties. Accelerated interfacial charge transfer and increased electron-hole pair separation enable hydrolysis-resistant CsPb2Br5/CdSe sensors to exhibit heightened sensitivity with an ultra-low detection limit (0.0124 µM) and a wide linear range (0.4-303.9 µM) in subsequent dopamine detection. Moreover, the CsPb2Br5/CdSe sensors show excellent anti-interference ability, as well as remarkable stability and reproducibility in water solvent. It is noteworthy that this work is conducted in an aqueous environment, which provides an inspiring and convenient way for photoelectric and photoelectrocatalysis applications based on water-resistant perovskites.

Synergetic enhancement effect of two-dimensional MoS2 nanosheets and metal organic framework-derived porous ZnO nanorods for photodegradation performance.

Two-dimensional transition metal dichalcogenides and semiconductor metal oxides have shown great potential in photocatalysis. However, their stability and efficiency need to be further improved. In this paper, porous ZnO nanorods with high specific surface area were prepared from metal-organic framework ZIF-8 by a simple hydrothermal method. A MoS2/ZnO composite was constructed by loading MoS2 onto the surface of porous ZnO nanorods. Compared with ZnO materials prepared by other methods, MoS2/ZnO prepared in this paper exhibits superior photocatalytic performance. The enhanced photocatalytic activity of the MoS2/ZnO composite can be attributed to the formation of heterojunctions and strong interaction between them, which greatly facilitate the separation of electrons and holes at the contact interface. In addition, due to the wide absorption region of the visible spectrum, MoS2 can greatly broaden the light absorption range of the material after the formation of the composite material, increase the utilization rate of visible light, and reduce the combination of electrons and holes. This study provides a new way to prepare cheap and efficient photocatalysts.

In situ fabrication of Z-scheme C3N4/Ti3C2/CdS for efficient photocatalytic hydrogen peroxide production.

Photocatalysis is a potential technology to produce hydrogen peroxide with low energy consumption and no pollution. However, when using traditional photocatalysts it is hard to meet the requirements of wide visible light absorption, high carrier separation rate and sufficient active sites. Graphitic carbon nitride (g-C3N4) has great potential in the photocatalytic production of hydrogen peroxide, but its photocatalytic performance is limited by a high carrier recombination ratio. Here, we fabricated the Z-Scheme heterojunction of C3N4/Ti3C2/CdS in situ. The large specific surface area of C3N4 can provide plenty of reactive sites, and the absorption efficiency under visible light is improved with the addition of Ti3C2 and CdS. The better conductivity of Ti3C2 reduces the charge transfer resistance. With the increase of surface charge carriers, the width of the space charge region decreases and the photocurrent density increases significantly. Under visible light irradiation, the H2O2 yield of the ternary photocatalyst reaches 256 µM L-1 h-1, which is about 6 times that of pristine C3N4. After three cycles, the high photocatalytic efficiency can still be maintained. In this paper, the reaction mechanism of photocatalytic hydrogen peroxide production by the C3N4/Ti3C2/CdS composite material is proposed through an in-depth study of energy band theory, which provides a new reference for the design and preparation of high-performance materials for photocatalytic hydrogen peroxide production.

Regenerative Effect of Mesenchymal Stem Cell on Cartilage Damage in a Porcine Model.

Osteoarthritis (OA) is a major public and animal health challenge with significant economic consequences. Cartilage degradation plays a critical role in the initiation and progression of degenerative joint diseases, such as OA. Mesenchymal stem cells (MSCs) have become increasingly popular in the field of cartilage regeneration due to their promising results. The objective of this preclinical study was to evaluate the regenerative effects of mesenchymal stem cells (MSCs) in the repair of knee cartilage defects using a porcine model. Seven healthy LYD breed white pigs, aged 9-10 weeks and weighing approximately 20 ± 3 kg, were used in the experimental protocol. Full-thickness defects measuring 8 mm in diameter and 5 mm in depth were induced in the lateral femoral condyle of the posterior limbs in both knee joints using a sterile puncture technique while the knee was maximally flexed. Following a 1-week induction phase, the pig treatment groups received a 0.3 million/kg MSC transplant into the damaged knee region, while the placebo group received a control solution as a treatment. Magnetic resonance imaging (MRI), computerized tomography (CT), visual macroscopic examination, histological analysis, and cytokine concentration analysis were used to assess cartilage regeneration. The findings revealed that human adipose-derived mesenchymal stem cells (hADSCs) were more effective in repairing cartilage than pig umbilical cord-derived mesenchymal stem cells (pUCMSCs). These results suggest that MSC-based treatments hold promise as a treatment option for cartilage repair, which aid in the treatment of OA. However, further studies with larger sample sizes and longer follow-up periods are required to fully demonstrate the safety and efficacy of these therapies in both animals and humans.

Scalable Edge-Oriented Metallic Two-Dimensional Layered Cu2Te Arrays for Electrocatalytic CO2 Methanation.

Copper-based nanomaterials are compelling for high-efficient, low-cost electrocatalytic CO2 reduction reaction (CO2RR) due to their exotic electronic and structural properties. However, controllable preparation of copper-based two-dimensional (2D) materials with abundant catalytically active sites, that guarantee high CO2RR performance, remains challenging, especially on a large scale. Here, an in situ vertical growth of scalable metallic 2D Cu2Te nanosheet arrays on commercial copper foils is demonstrated for efficient CO2-to-CH4 electrocatalysis. The edge-oriented growth of Cu2Te nanosheets with tunable sizes and thicknesses is facilely attained by a two-step process of chemical etching and chemical vapor deposition. These active sites abounding on highly exposed edges of Cu2Te nanosheets greatly promote the electroreduction of CO2 into CH4 at a potential as low as -0.4 V (versus the reversible hydrogen electrode), while suppressing hydrogen evolution reaction. When a flow cell is employed to accelerate the mass transfer, the faradaic efficiency reaches ∼63% at an applied current density of 300 mA cm-2. These findings will provide great possibilities for developing scalable, energy-efficient Cu-based CO2RR electrocatalysts.

Knee joint injuries in young basketball players / Lesões na articulação do joelho em jovens jogadores de basquetebol / Lesiones de la articulación de la rodilla en jóvenes jugadores de baloncesto

ABSTRACT Introduction Basketball is a popular sport globally, and as the development of college basketball develops, basketball injuries also tend to increase. The knee has the highest injuries and problems incidence, reducing the athlete's ability and shortening their professional career. Objective Explore the causes and characteristics of knee joint injuries in basketball players, comparing their different levels, performances, and positions. Methods 600 college basketball players were studied. Current and past injuries were collected. A questionnaire on lifestyle, behavior, and habits was also applied, and their levels of physical ability and knowledge were also evaluated. Statistical methods were employed to investigate the characteristics and causes of knee joint injuries in young athletes. Results Among knee joint injuries of adolescent basketball players, there were more medial collateral ligament injuries and meniscal injuries. The probabilities are 34.1% and 24.3%, respectively. Patellar strain and cruciate ligament injury accounted for 12.1% and 19.5%, respectively, and the probability of fracture injury was 2.4%. Conclusion The knee joint is one of the most vulnerable joints in basketball. The consequences of its injury can bring an athletic career down and have a considerable impact on athletes' physical and mental health. Evidence Level II; Therapeutic Studies - Investigating the results.

RESUMO Introdução O basquete é um esporte popular em todo o mundo e com o desenvolvimento do basquetebol universitário, as lesões causadas pelo basquetebol também tendem a aumentar. O joelho possui o maior índice de lesões e problemas nessa articulação também reduzem a capacidade do atleta, encurtando a sua carreira profissional. Objetivo Explorar as causas e características das lesões na articulação do joelho em jogadores de basquetebol comparando seus diferentes níveis, desempenhos e posições. Métodos 600 universitários jogadores de basquete foram estudados. Foram arquivadas as lesões atuais e pregressas. Um questionário sobre estilo de vida, comportamento e hábitos também foi aplicado; seus níveis de habilidade física e conhecimento foram avaliados. Métodos estatísticos investigaram as características e causas das lesões na articulação do joelho nos jovens atletas. Resultados Entre as lesões articulares de joelho nos jogadores adolescentes de basquete, houve mais lesões ligamentares colaterais mediais e lesões meniscais. As probabilidades são de 34,1% e 24,3%, respectivamente. A tensão patelar e a lesão do ligamento cruzado representaram 12,1% e 19,5%, respectivamente, e a probabilidade de lesão por fratura foi de 2,4%. Conclusão A articulação do joelho é uma das partes mais vulneráveis do basquetebol. As consequências de sua lesão podem acarretar o fim da carreira esportiva, tendo um impacto considerável sobre a saúde física e mental dos atletas. Nível de evidência II; Estudos Terapêuticos - Investigação de Resultados.

RESUMEN Introducción El baloncesto es un deporte popular en todo el mundo y con el desarrollo del baloncesto universitario, las lesiones causadas por el baloncesto también tienden a aumentar. La rodilla tiene el mayor índice de lesiones y los problemas en esta articulación también reducen la capacidad del deportista, acortando su carrera profesional. Objetivo Explorar las causas y características de las lesiones de la articulación de la rodilla en jugadores de baloncesto comparando sus diferentes niveles, rendimientos y posiciones. Métodos Se estudiaron 600 jugadores de baloncesto universitario. Se presentaron las lesiones actuales y pasadas. También se aplicó un cuestionario sobre el estilo de vida, el comportamiento y los hábitos; y también se evaluaron sus niveles de capacidad física y conocimientos. Se emplearon métodos estadísticos para investigar las características y las causas de las lesiones de la articulación de la rodilla en atletas jóvenes. Resultados Entre las lesiones de la articulación de la rodilla de los jugadores de baloncesto adolescentes, hubo más lesiones del ligamento colateral medial y de menisco. Las probabilidades son del 34,1% y del 24,3%, respectivamente. La distensión rotuliana y la lesión del ligamento cruzado representaron el 12,1% y el 19,5%, respectivamente, y la probabilidad de lesión por fractura fue del 2,4%. Conclusión La articulación de la rodilla es una de las partes más vulnerables del baloncesto. Las consecuencias de su lesión pueden llevar al fin de una carrera deportiva, teniendo un impacto considerable en la salud física y mental de los atletas. Nivel de evidencia II; Estudios terapéuticos - Investigación de resultados.

One-pot synthesis of 3D Au nanoparticle clusters with tunable size and their application.

In general, the preparation of Au nanoparticle clusters (NPCs) is more challenging than that of nanoparticles. The traditional multi-step method for preparing Au NPCs is time consuming and highly sensitive to the reaction conditions. Here, we report a simple and feasible method for the rapid preparation of Au NPCs (∼30 min), in which Au (III) is reduced to Au (0) by trisodium citrate, and assembled into NPCs in the presence of a trace amount of cysteine. The surface plasmon resonance peak of the Au NPCs is tunable and ranged from visible to near-IR regions by varying the content of cysteine added. The growth process of Au NPCs was monitored by dynamic light scattering, UV-vis absorption spectroscopy and transmission electron microscopy. Their elemental composition, chemical state and molecular structure of the sample surface were measured by x-ray photoelectron spectroscopy. The proposed synthesis mechanism has guiding significance for the preparation of other NPCs. Au NPCs used as surface-enhanced Raman spectroscopy substrate has a good enhancement effect because of its unique morphology.

Stepwise Synthesis of Au@CdS-CdS Nanoflowers and Their Enhanced Photocatalytic Properties.

Fabrication of hybrid nanostructures with complex morphologies and high photocatalytic activity is a difficult challenge because these particles require extremely high preparation skills and are not always practical. Here, hierarchical flower-like Au@CdS-CdS nanoparticles (Au@CdS-CdS nanoflowers) have been synthesized using a stepwise method. The Au@CdS-CdS nanoflowers are consisted of Au core, CdS shell, and CdS nanorods. The UV-Vis absorption range of the Au@CdS-CdS nanoflowers reaches up to 850 nm which covers the whole visible range (400-760 nm). Photoinduced charge transfer property of Au@CdS-CdS nanoflowers was demonstrated using photoluminescence (PL) spectroscopy. Compared to CdS counterparts and Au@CdS counterparts, Au@CdS-CdS nanoflowers demonstrated the highest photocatalytic degradation rate under irradiation of λ = 400-780 nm and λ = 600-780 nm, respectively. Based on structure and morphology analyses, we have proposed a possible formation mechanism of the hybrid nanostructure which can be used to guide the design of other metal-semiconductor nanostructures with complex morphologies.

FOLR1 increases sensitivity to cisplatin treatment in ovarian cancer cells.

BACKGROUND: Whether there is a mechanistic link between FOLR1 and response to cisplatin has not been extensively examined. In this study, we determine the expression of FOLR1 in ovarian cancer and examine if FOLR1 levels influence response to cisplatin. RESULTS: (1) FOLR1 protein expression was lowest in normal ovarian tissue, higher in benign ovarian tumors, and highest in malignant tumors (P < 0.01). (2) FOLR1 expression was decreased in platinum drug-resistant ovarian tumors compared to sensitive tumors (P < 0.01). Consistent with this, FOLR1 expression in tumors progressing following cisplatin treatment was lower than levels in tumors in remission (P < 0.01). (3) FOLR1 was successfully overexpressed at both the mRNA and protein levels following transfection in SKOV3 cells. (4) SKOV3 cells with FOLR1 overexpression were the most sensitive to cisplatin treatment (IC50 = 3.60 µg/ml) and exhibited the highest inhibition rates in the presence of the drug (P < 0.05). (5) The rate of apoptosis of SKOV3 cells increased with cisplatin treatment in a dose- and time-dependent manner (P < 0.05). Cisplatin also induced S phase arrest in a concentration-dependent manner (P < 0.05). Apoptosis and S phase proportion were significantly altered by FOLR1 overexpression (P < 0.05). CONCLUSION: FOLR1 may be a useful biomarker for ovarian cancer, and it may be useful as a therapeutic application to improve sensitivity to cisplatin treatment.

Two-step phase shifting differential-recording digital holographic microscopy.

We present two-step phase-shifting differential-recording digital holographic microscopy (TPD-DH in microscopy) for phase imaging of microscopic transparent elements. Two CCDs are employed to record two interferograms at two different defocusing distances. The interferograms on the two CCD cameras are shifted for a phase retarder 0 and π via an all-optics phase shifting unit. A novel algorithm is proposed to reconstruct both amplitude and phase distributions of the object wave from the recorded interferograms. This method has the same spectrum bandwidth and measurement accuracy with those of conventional four-step phase-shifting interferometry (FS-PSI), whereas it reduces the measurement time by half.

In situ SERS monitoring of plasmonic nano-dopants during photopolymerization.

The motion of the plasmonic nano-dopant in photopolymers was monitored in situ and in real time using the surface-enhanced Raman scattering (SERS) technique. Here an Au@MBA@Ag (core-molecule-shell) nanoparticle colloid was synthesized to act as the nano-dopant and adsorbed 4-mercaptobenzoic acid (MBA) between the Au cells and Ag shells as the internal standard. The changes of the MBA signal closely reflect the motion of nanoparticles, since the MBA signal itself has time stability. Experimental data indicate that the optimized concentration of the nano-dopant can be obtained based on the peak intensity change of MBA at 1583 cm-1. This Letter provides a novel way for in situ monitoring of photophysicial and photochemical processes.

Morphology and Optical Properties of RF Sputtering Deposited Indium Nitride Layers Under Different N2/Ar Ratio.

InN thin films were prepared using reactive radio frequency sputtering on (111) Si substrates under different N2/Ar ratio. The surface morphology and optical properties of InN thin films were characterized by X-ray diffraction, atomic force microscopy, scanning electron microscope, energy dispersive spectrometer, and UV-visible-NIR spectrophotometer at room temperature. It was found that the growth rate and surface RMS roughness of InN layers all significantly decreased with the increasing of N2 content in the sputtering gas. All the InN films were wurtzite structure with the proportion of N2 increasing from 40% to 100% in the mixture gas. The highly c-axis orientation InN films could only be obtained in the composition ratios of N2 higher than 90%. The atomic percentage of N is much higher than that of In at high N2 content films, which mainly due to the chemical reaction on the surface of Si substrate. The apparent optical band gap energy is estimated at 1.83 eV. However, the InN absorption band tail is strongly influenced by the sputtering due to a change in the species of the plasma.

Metal Oxide Nanomaterials in Nanomedicine: Applications in Photodynamic Therapy and Potential Toxicity.

Metal oxide nanomaterials have exhibited excellent performance as nanomedicines in photodynamic therapy (PDT) for cancer and infection treatment. Their unique and tunable physicochemical properties advance them as promising alternatives in drug delivery, early diagnosis, imaging, and treatment against various tumors and infectious diseases. Moreover, the implementation of nanophototherapy in deep tissue sites is enhanced by advancements in photosensitization technology. Notwithstanding the progress made in emerging metal oxide nanomaterials-derived PDT, the potential toxicity towards adjunct tissues associated with this approach remains challenging. Regulation and legislation have also been recommended and subsequently enacted in response to public concerns related to large-scale production, transportation, use, and disposal of those nanomaterials. Consequently, a quantitative structure-activity relationship (QSAR) paradigm has been adopted and is widely used in evaluating and predicting the side effects of nanomedicines, thus influencing their design and fabrication. This article briefly reviews the application of metal oxide nanomaterials in PDT and their associated adverse impacts as reported in recent publications. The future trends and implications of this platform in nanomedicine are also highlighted. However, more studies and efforts have to be carried out for developing novel nano-therapeutics with high selectivity, sensitivity, biocompatibility, and minimal side effects in PDT.

Effect of incorporation of different modified Al2O3 nanoparticles on holographic characteristics of PVA/AA photopolymer composites.

Al2O3 nanoparticles modified with different chemical reagents, prepared by using three chemical dispersants [high definition (HD), sodium dodecyl benzene sulfonate, and cetyl trimethyl ammonium chloride], were doped into photopolymer films in a polyvinyl alcohol/acrylamide (PVA/AA) system, respectively. A 647 nm Ar-Kr laser was used to expose and study the holographic properties of the samples. The research shows that doping Al2O3 nanoparticles into PVA/AA photopolymer film leads to different levels of improvement of the holographic characteristics. The diffraction efficiency of the sample can be raised to 93.8%, the maximum refractive index modulation increased to 2.28×10(-3), the shrinkage can be depressed to 0.8%, and the Bragg mismatch is 0.04°, while the concentration of 10 nm Al2O3 nanoparticles modified by HD dispersant is 1.02×10(-3) mol·L(-1).

Using experimental data of Escherichia coli to develop a QSAR model for predicting the photo-induced cytotoxicity of metal oxide nanoparticles.

A quantitative structure-activity relationship (QSAR) study of seventeen metal oxide nanoparticles (MNPs), in regard to their photo-induced toxicity to bacteria Escherichia coli, was developed by using quantum chemical methods. A simple and statistically significant QSAR model (F=33.83, R(2)=0.87) was successfully developed for the dark group based on two descriptors, absolute electronegativity of the metal and the metal oxide. Similarly, a best correlation (F=20.51, R(2)=0.804) was obtained to predict the photo-induced toxicity of MNPs by using two descriptors, molar heat capacity and average of the alpha and beta LUMO (lowest unoccupied molecular orbital) energies of the metal oxide. Revelation of these influential molecular descriptors may be useful in elucidating the mechanisms of nanotoxicity and for predicting the environmental risk associated with release of the MNPs. In addition, the developed model may have a role in the future design and manufacture of safe nanomaterials.

[Biological effects of upregulated expression of transfected FOLR1 gene on SKOV3 cell lines acted by cisplatin].

OBJECTIVE: To explore biological effects of up-regulated expression of transfected FOLR1 gene on SKOV3 cell lines following action by cisplatin (DDP) . METHODS: Three groups of cells originated from the same SKOV3 cell line were used in this research, including the SKOV3 cell line(blank control), the cell line transfected with lentiviral pWPI plasmid(no-load control) and the cell line transfected with FOLR1 gene via lentiviral pWPI plasmid(experimental group). Next, the mRNA and protein expression of FOLR1 gene in the three groups were detected by reverse transcription (RT) -PCR and western blot, respectively. Methyl thiazolyl tetrazolium (MTT) assay was used to analysis cells growth curve and identify their sensitivity to cisplatin, and their half inhibition concentration(IC50) values were calculated. Based on the IC50 value(3.6 µg/ml) in the experimental group, different levels of cisplatin concentration (0.5×IC50, 1×IC50, 2×IC50, respectively) were administered to the three groups of cells, and the inhibition rates, apoptosis rates as well as apoptosis proportion of each group after 24, 48, 72 hours were further recorded.Finally, the residual cisplatin concentrations in the three group cells acted successively by 1×IC50 cisplatin for 48 hours were measured by high performance liquid chromatography (HPLC) . P value less than 0.05 were defined as statistically significant. RESULTS: RT-PCR and western blot detection showed that stable mRNA and protein expression of the FOLR1 gene in the experimental group while the other two groups were not. MTT assay demonstrated that higher cell growth rate, sensitivity to cisplatin(IC50 = 3.6 µg/ml) and inhibition rate in the experimental group compared with those in the other two groups (P < 0.05) , which showed no significance in intergroup comparison(P > 0.05). Flow cytometry showed apoptosis rates among three groups increased with higher cisplatin concentrations and longer action duration in dosage-time dependent manner (P < 0.05) , and the proportion of S phase cells increased with higher cisplatin concentration in dosage-dependent manner (P < 0.05) ;for the same concentration and duration, the experimental group showed significantly different apoptosis rates and S phase cells compared with the other two groups, which demonstrated no significance in intergroup comparison (P > 0.05) . After action by cisplatin(3.6 µg/ml) for 48 hours, HPLC showed significantly higher residual cisplatin concentration (2.60 ± 0.21) µg/10(6) cell counts in experimental group than those in no-load control group (1.49 ± 0.12) µg/10(6) cell counts and blank control group(1.54 ± 0.11) µg/10(6) cell counts, respectively (P < 0.05) , and the comparison within the latter two groups showed no significance (P > 0.05). CONCLUSION: Up-regulated expression of the transfected FOLR1 gene in SKOV3 cells may be associated with higher sensitivity to cisplatin, residual cisplatin concentration and higher proportion of S phase cells, and tended to inhibit cancer cells growth and induce apoptosis.

Binding of O2 and NO to heme in heme-nitric oxide/oxygen-binding (H-NOX) proteins. A theoretical study.

The binding of O2 and NO to heme in heme-nitric oxide/oxygen-binding (H-NOX) proteins has been investigated with DFT as well as dispersion-corrected DFT methods. The local protein environment was accounted for by including the six nearest surrounding residues in the studied systems. Attention was also paid to the effects of the protein environment, particularly the distal Tyr140, on the proximal iron-histidine (Fe-His) binding. The Heme-AB (AB = O2, NO) and Fe-His binding energies in iron porphyrin FeP(His)(AB), myoglobin Mb(AB), H-NOX(AB), and Tyr140 → Phe mutated H-NOX[Y140F(AB)] were determined for comparison. The calculated stabilization of bound O2 is even higher in H-NOX than that in a myoglobin (Mb), consistent with the observation that the H-NOX domain of T. tengcongensis has a very high affinity for its oxygen molecule. Among the two different X-ray crystal structures for the Tt H-NOX protein, the calculated results for both AB = O2 and NO appear to support the crystal structure with the PDB code 1XBN , where the Trp9 and Asn74 residues do not form a hydrogen-bonding network with Tyr140. A hydrogen bond interaction from the polar residue does not have obvious effects on the Fe-His binding strength, but a dispersion contribution to Ebind(Fe-His) may be significant, depending on the crystal structure used. We speculate that the Fe-His binding strength in the deoxy form of a native protein could be an important factor in determining whether the bond of His to Fe is broken or maintained upon binding of NO to Fe.

[Construction and identification of lentiviral vector carrying FOLR1 gene].

Through this research a lentiviral vector expressing the gene of folate-binding protein-1 (FOLR1) was constructed and the corrsponding expression products were identified. Firstly, full-length of the FORL1 gene was amplified by PCR and cloned into the plasmid pWPI. Then it was further confirmed by PCR and sequencing. Secondly, after the recombinant pWPI and its helper plasmid co-transfected the virus packaging 293T cells, SKOV3 cells were infected with the virus particles and sorted by flow cytometry. Thirdly, the FOLR1 gene was detected by RT-PCR and its protein expression was detected by Western blot. Finally, the recombinant expression vector was successfully constructed, and lentiviruses were successfully packaged by the 293T cells. A great quantity of green fluorescent cells could be seen after the SKOV3 cells were effectively infected with the lentiviruses carrying the FOLR1 gene. The sorting could be done and detected by cytometrying the FORL1 gene and its stable expression by the two methods above, which laid experimental foundation for exploring its biological function in ovarian cancers.

Effects of local protein environment on the binding of diatomic molecules to heme in myoglobins. DFT and dispersion-corrected DFT studies.

The heme-AB binding energies (AB = CO, O2) in a wild-type myoglobin (Mb) and two mutants (H64L, V68N) of Mb have been investigated in detail with both DFT and dispersion-corrected DFT methods, where H64L and V68N represent two different, opposite situations. Several dispersion correction approaches were tested in the calculations. The effects of the local protein environment were accounted for by including the five nearest surrounding residues in the calculated systems. The specific role of histidine-64 in the distal pocket was examined in more detail in this study than in other studies in the literature. Although the present calculated results do not change the previous conclusion that the hydrogen bonding by the distal histidine-64 residue plays a major role in the O2/CO discrimination by Mb, more details about the interaction between the protein environment and the bound ligand have been revealed in this study by comparing the binding energies of AB to a porphyrin and the various myoglobins. The changes in the experimental binding energies from one system to another are well reproduced by the calculations. Without constraints on the residues in geometry optimization, the dispersion correction is necessary, since it improves the calculated structures and energetic results significantly.