Rare-earth vanadates, niobates, and tantalates have shown self-activated and Bi3+-activated emissions. Their intrinsic emission has been attributed to self-trapped excitons (STEs), but the detailed ...information concerning the geometric and electronic structures of the excited states has remained unknown. Regarding the Bi3+ dopants in these hosts, the luminescence has been attributed to two different mechanisms, i.e., Bi3+↔ (V/Nb/Ta)5+ metal-to-metal charge transfer and interconfigurational (3P0,1 → 1S0) transition. Here, first-principles calculations using hybrid functionals are employed to resolve these issues. The STEs are shown to be composed of an electron localized on an individual vanadium, niobium, or tantalum ion and a hole localized on a single nearest-neighbor oxygen ion that is not shared by covalent complexes, and the bond length of the (V/Nb/Ta)–O bond with oxygen accommodating the hole is significantly elongated. The Bi3+-related emission is identified as the recombination of an exciton with a hole and an electron localized correspondingly at Bi3+ and (V/Nb/Ta)5+ ions, while the excitation is dominated by the 6s → 6p transition of Bi3+. Furthermore, Bi3+ has a hole trap level in all of the hosts considered with the trap levels in the vacuum-referred binding energy diagram being nearly flat but has an electron trap level only in rare-earth tantalates. Furthermore, the long-wavelength emission observed in niobates and tantalates is interpreted based on our calculations to be excitons bound to intrinsic defects. The insights gained in this work deepen our understanding of the STEs and form the basis for interpreting similar luminescence phenomena in other ternary closed-shell d0 transition-metal oxides. The clarification of Bi3+-related transitions and the analyses with the vacuum-referred binding energy diagram may find applications for the design and optimization of Bi3+-activated phosphors.
Increasing zinc (Zn) concentration in wheat grain is important to minimize human dietary Zn deficiency. This study aimed to investigate the effect of foliar Zn and soil nitrogen (N) applications on ...the accumulation and distribution of N and Zn in grain pearling fractions, N remobilization, and the relationships between nutrient concentration in the vegetative tissues and grain or its fractions in two cropping years in the North China Plain. The results showed a progressive decrease in N and Zn concentrations from the outer to the inner parts of grain, with most of the accumulation in the core endosperm. Foliar Zn application significantly increased N concentration in the pericarp, and soil N application increased N concentration in each grain fraction. Both treatments significantly increased core endosperm Zn concentration. Foliar Zn had no effect on grain N and Zn distribution. Soil N application made N concentrated in the aleurone, promoted Zn translocation to the core endosperm and also increased N remobilization and its efficiency from the shoot to the grain, but no improved contribution to grain was found. N concentration in grain and its fractions were positively correlated with N in vegetative organs at anthesis and maturity, while positive correlations were obtained between N concentration in the pericarp and progressive central area of the endosperm and Zn concentration in the core endosperm. Thus, foliar Zn and soil N applications effectively increased yield and N and Zn concentrations in the wheat grain, particularly in the endosperm, and could be promising strategies to address Zn deficiency.
The purpose of this paper is to synthesize a micrometric inorganic perovskite CsPbCl3:Nd3+ and investigate the impact of doping with rare-earth ions on structural and optical properties, as well as ...energy transfer pathways between the host and dopant. Herein, we report the solid-state reaction synthesis of a concentration series of CsPbCl3:x%Nd3+ annealed under a nitrogen atmosphere. Additional doping of a material that already exhibits luminescence with an optically active ion increases its application potential. Structural features were determined using X-ray powder diffraction and Raman spectroscopy. Morphology studies performed with scanning electron microscopy revealed micrometric, well-separated cubic-like crystallites with a good distribution of individual elements. Surprisingly, a photoluminescence (PL) study showed that only blue emission appears when the material is excited with a diode operating in the UV range. Apparently, the emission of Nd3+ ions can only be obtained with direct excitation of the lanthanide. The photoluminescence excitation (PLE) spectrum monitored for Nd3+ emission confirmed the lack of energy transfer between the host and dopant. Possible explanations for this behavior have been put forth and substantiated by the first-principles electronic structure calculations in the framework of hybrid density functional theory.
Retroperitoneal malignant schwannomas are extremely rare. Only a few cases have been reported, only one of which occurred in a child. We herein report a case of retroperitoneal malignant schwannoma ...in a 2-year-old boy who presented with a painless mass in the right lumbar region. The mass had gradually enlarged during a 1-year period, and it was about the size of the patient’s fist at the time of consultation. Whole-abdomen computed tomography revealed a space-occupying lesion in the retroperitoneum infiltrating from the L1 to L4 spinal canal. A preoperative diagnosis of a retroperitoneal tumor was made, and complete tumorectomy was performed. Postoperative pathological examination showed a malignant schwannoma. The tumor recurred 1 month after the first operation, and a second complete excision was carried out; the postoperative pathologic examination findings were similar to the previous findings. The patient recovered well and continued to undergo close follow-up.
Low temperature, infrared absorption spectra of gadolinium gallium garnet crystals doped with Ce are presented. In the region of intraconfigurational 4functionof-4functionof transitions the spectra ...exhibit existence of at least two different, major Ce super(3+) related centers in the GGG crystals and also some other centers at lower concentration. The spectrum of 4functionof-4functionof intrashell transitions of Ce super(3+) ions extends up to about 3700 cm super(-1) due to the large splitting of the super(2)F sub(7/2) excited state. In the visible region the absorption spectrum shows influence of symmetry-related selection rules. The absorption coefficient changes in the region of 4functionof super(1)-5d super(1) transitions due to thermal population of the second level, belonging to the super(2)F sub(5/2) ground state. This suggests that the symmetry of the site occupied by Ce super(3+) ions, which substitute Gd super(3+), is higher than D sub(2) expected for garnet hosts.
Objective
Transverse island pedicle flap (TIPF) plus transected urethral plate-preserving urethroplasty is increasingly used for treatment of severe hypospadias. We aimed to reduce the occurrence of ...urethral strictures in patients undergoing such procedures.
Methods
Sixty-five patients with severe hypospadias were enrolled. Thirty-two patients underwent onlay-tube-onlay urethroplasty (Group A), and 33 patients underwent modified Duplay urethroplasty (Group B). Postoperative complications were recorded, including fistulas, urethral strictures, and diverticula.
Results
Three patients (9.4%) in Group A and 10 patients (30.3%) in group B had urethrocutaneous fistulas. Three patients (9.4%) in Group A and 0 patients (0%) in Group B had urethral strictures. No patient in the two groups had symptoms of diverticulum or penile chordee. The results of uroflowmetry were better in Group B than Group A, when comparing uroflow patterns.
Conclusions
TIPF plus transected urethral plate-preserving urethroplasty can lower the occurrence of stricture, which is a challenging complication. The occurrence of stricture was lower in patients who underwent modified Duplay urethroplasty, and neourethral function and quality were better in these patient. Thus, this modified procedure can be used for treatment of severe hypospadias.
AP2/EREBP transcription factors (TFs) play functionally important roles in plant growth and development, especially in hormonal regulation and in response to environmental stress. Here we reported ...verification and correction of annotation through an exhaustive cDNA cloning and sequence analysis performed on 145 of 147 gene family members. A RACE analysis performed on genes with potential in-frame up-stream ATG codon resulted in identification of At2g28520 as an authentic AP2/EREBP member and corrected ORF annotations for three other members. A further phylogenetic analysis of this updated and likely complete family divided it into three major subfamilies. The expression patterns of the AP2/EREBP family members among the 11 organ or tissue types were examined using an oligo microarray and their hormonal and environmental responsiveness were further characterized using cDNA custom macroarrays. These detailed expression profile results provide strong support for a role for AP2/EREBP family members in development and in response to environmental stimuli, and a foundation for future functional analysis of this gene family.
A reasonable allocation of load distribution is expected when the full capacity of rolling equipment is exerted, and energy conservation and strip quality requirements are satisfied. In this work, ...the minimum value of the mill consumptive power summation and the optimum of the mill shape are used as the target function. Based on equipment parameters of a national hot strip rolling mill, a load distribution optimization method (subjected to certain constraints) was applied and a Max-Min ant-colony algorithm was subsequently used to optimize the load distribution of the mill. The optimization value was determined from the optimal path chosen by ants, and the optimum load distribution was obtained after a series of iterations. The compression ratio from upstream stands to downstream stands decreased gradually after optimization by this method, and the proportional crowns varied less than those associated with the traditional energy method. In fact, the amplitude of fluctuation was reduced by nearly 50%, which is favorable for strip shape controlling, and the total dissipative power was lower than that of the energy consumption method. Moreover, the overall power can be reduced by 4.19%, and an optimal rolling load distribution of the hot strip rolling process can be obtained.
Filterless narrowband near-infrared photodetectors (NIRPDs) offer significantly reducing cost and the system volume for various applications, but limited by the poor photosensitivity. Herein, we ...theoretically and experimentally demonstrate a novel class of sensitive filterless NIRPDs in CsPbF3: Zn2+-Yb3+- Tm3+ (or Er3+) perovskite nanocrystals (PeNCs)/Au nanorods (NRs) array hybrid via direct photon-electric upconverion (UC) from ground state of Yb3+- Tm3+ (or Er3+) to conduction band of PeNCs. It shows the selectively spectral photodetection at 980-nm NIR region with all full-width at half-maximum of 20 nm, high responsivity of 106 A/W, detectivity of 1.52 × 1012 Jones, and external quantum efficiency of 135%. The excellent performance can be mainly ascribed to (1) direct photon-electric UC mechanism; (2) the reduced trapping-center density, high carrier mobility, and increased extraction and separation efficient of election-hole pairs of PeNCs; (3) localized surface plasmon enhancement. Our findings open the exciting potential for developing the next-generation narrow NIRPDs.
Schematic illustration of electron injection process of CsPbF3: Zn2+ - Yb3+ - Er3+PeNCs for NIRPDs. Display omitted
•Herein, we theoretically and experimentally demonstrate a novel class of sensitive filterless NIRPDs in CsPbF3: Zn2+-Yb3+- Tm3+ (or Er3+) perovskite nanocrystals (PeNCs)/Au nanorods (NRs) array hybrid via direct photon-electric upconverion (UC) from ground state of Yb3+- Tm3+ (or Er3+) to conduction band of PeNCs.•It shows the selectively spectral photodetection at 980-nm NIR region with all full-width at half-maximum of 20 nm, high responsivity of 106 A/W, detectivity of 1.52 × 1012 Jones, and external quantum efficiency of 135%.•The excellent performance can be mainly ascribed to (1) direct photon-electric UC mechanism; (2) the reduced trapping-center density, high carrier mobility, and increased extraction and separation efficient of election-hole pairs of PeNCs; (3) localized surface plasmon enhancement.•This work is of general interests to researchers working in perovskite nanocrystals, upconversion luminescence materials, solar energy harvesting, photodetectors.
Congenital giant megaureter (CGM) is uncommon in the pediatric population. The major clinical presentations are marked protruberances and abdominal cysts.
We reported a case of CGM with almost the ...whole left ureter dilation accompanied with a 1 cm stricture at the entrance of the bladder and renal dysplasia, immediately compressing the contralateral ureter and causing bilateral hydronephrosis for the first time. At one-stage of the operation, a left nephrostomy with a right ureterolysis were performed, and a poor left kidney function was found. Then, the left kidney and ureter were cut off by nephroureterectomy at the second-stage. Eventually, the follow-up showed that the patient recovered well by abdominal ultrasound.
Based on the findings of these reported literatures, CGM is rare. The physical and imaging examinations are essential for the diagnosis of CGM, and the appropriate treatment methods should be performed based on patients' specific condition.
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