Optimal Size Threshold for MRI-Detected Retropharyngeal Lymph Nodes to Predict Outcomes in Nasopharyngeal Carcinoma: A Two-Center Study.

BACKGROUND. Retropharyngeal lymph node (RLN) metastases have profound prognostic implications in patients with nasopharyngeal carcinoma (NPC). However, the AJCC staging system does not specify a size threshold for determining RLN involvement, resulting in inconsistent thresholds in practice. OBJECTIVE. The purpose of this article was to determine the optimal size threshold for determining the presence of metastatic RLNs on MRI in patients with NPC, in terms of outcome predictions. METHODS. This retrospective study included 1752 patients (median age, 46 years; 1297 men, 455 women) with NPC treated by intensity-modulated radiotherapy (RT) from January 2010 to March 2014 from two hospitals; 438 patients underwent MRI 3-4 months after treatment. Two radiologists measured the minimal axial diameter (MAD) of the largest RLN for each patient using a consensus process. A third radiologist measured MAD in 260 randomly selected patients to assess interobserver agreement. Initial ROC and restricted cubic spline (RCS) analyses were used to derive an optimal MAD threshold for predicting progression-free survival (PFS). The threshold's predictive utility was assessed in multivariable Cox regression analyses, controlling for standard clinical predictors. The threshold's utility for predicting PFS and overall survival (OS) was compared with a 5-mm threshold using Kaplan-Meier curves and log-rank tests. RESULTS. The intraclass correlation coefficient for MAD was 0.943. ROC and RCS analyses yielded an optimal threshold of 6 mm. In multivariable analyses, MAD of 6 mm and greater independently predicted PFS in all patients (HR = 1.35, p = .02), patients with N0 or N1 disease (HR = 1.80, p = .008), and patients who underwent posttreatment MRI (HR = 1.68, p = .04). In patients with N1 disease without cervical lymph node involvement, 5-year PFS was worse for MAD greater than or equal to 6 mm than for MAD that was greater than or equal to 5 mm but less than 6 mm (77.2% vs 89.7%, p = .03). OS was significantly different in patients with stage I and stage II disease defined using a 6-mm threshold (p = .04), but not using a 5-mm threshold (p = .09). The 5-year PFS rate was associated with a post-RT MAD of 6 mm and greater (HR = 1.68, p = .04) but not a post-RT MAD greater than or equal to 5 mm (HR = 1.09, p = .71). CONCLUSION. The findings support a threshold MAD of 6 mm for determining RLN involvement in patients with NPC. CLINICAL IMPACT. Future AJCC staging updates should consider incorporation of the 6-mm threshold for N-category and tumor-stage determinations.

More light components and less light damage on rats' eyes: evidence for the photobiomodulation and spectral opponency.

The blue-light hazard (BLH) has raised concerns with the increasing applications of white light-emitting diodes (LEDs). Many researchers believed that the shorter wavelength or more light components generally resulted in more severe retinal damage. In this study, based on the conventional phosphor-coated white LED, we added azure (484 nm), cyan (511 nm), and red (664 nm) light to fabricate the low-hazard light source. The low-hazard light sources and conventional white LED illuminated 68 Sprague-Dawley (SD) rats for 7 days. Before and after light exposure, we measured the retinal function, thickness of retinal layers, and fundus photographs. The expression levels of autophagy-related proteins and the activities of oxidation-related biochemical indicators were also measured to investigate the mechanisms of damaging or protecting the retina. With the same correlated color temperature (CCT), the low-hazard light source results in significantly less damage on the retinal function and photoreceptors, even if it has two times illuminance and blue-light hazard-weighted irradiance ([Formula: see text]) than conventional white LED. The results illustrated that [Formula: see text] proposed by IEC 62471 could not exactly evaluate the light damage on rats' retinas. We also figured out that more light components could result in less light damage, which provided evidence for the photobiomodulation (PBM) and spectral opponency on light damage.

Recombineering-Mediated Sinorhizobium meliloti Rm1021 Gene Deletion.

Sinorhizobium meliloti Rm1021 (S. meliloti Rm1021) is a Gram-negative, soil-dwelling α-proteobacterium which serves as a model microorganism for the studies of symbiotic nitrogen fixation. The S. meliloti Rm1021 genome consists of one chromosome and two megaplasmids, pSymA and pSymB. Gene deletion is an essential tool for the elucidation of gene function and generation of mutants with improved properties. However, only two gene deletion methods, counterselectable marker sacB-based and FLP/FRT, Cre/loxP site-specific recombination, have been reported for S. meliloti Rm1021 gene deletion. Both methods require time-consuming and tedious gene cloning and conjugation steps. Herein, a λ Red recombineering-mediated gene deletion strategy is reported. The mutant was obtained via electroporating overlap-extension PCR-generated linear targeting DNA into Red-proficient cells. One gene each from the S. meliloti Rm1021 chromosome, megaplasmid SymA and pSymB was deleted, with deletion efficiency up to 100%. The straightforward and highly efficient recombineering procedure holds the promise to be a general gene manipulation method for S. meliloti Rm1021.

CRISPR/Cas9-assisted ssDNA recombineering for site-directed mutagenesis and saturation mutagenesis of plasmid-encoded genes.

Site-directed and saturation mutagenesis are critical DNA methodologies for studying protein structure and function. For plasmid-based gene mutation, PCR and overlap-extension PCR involve tedious cloning steps. When the plasmid size is large, PCR yield may be too low for cloning; and for saturation mutagenesis of a single codon, one experiment may not enough to generate all twenty coding variants. Oligo-mediated recombineering sidesteps the complicated cloning process by homologous recombination between a mutagenic oligo and its target site. However, the low recombineering efficiency and inability to select for the recombinant makes it necessary to screen a large number of clones. Herein, we describe two plasmid-based mutagenic strategies: CRISPR/Cas9-assisted ssDNA recombineering for site-directed mutagenesis (CRM) and saturation mutagenesis (CRSM). CRM and CRSM involve co-electroporation of target plasmid, sgRNA expression plasmid and mutagenic oligonucleotide into Escherichia coli cells with induced expression of λ-Red recombinase and Cas9, followed by plasmid extraction and characterization. We established CRM and CRSM via ampicillin resistance gene repair and mutagenesis of N-acetyl­D­neuraminic acid aldolase. The mutational efficiency was between 80 and 100% and all twenty amino acid coding variants were obtained at a target site via a single CRSM strategy. CRM and CRSM have the potential to be general plasmid-based gene mutagenesis tools.

Characterization of a novel Escherichia coli recombineering selection/counterselection cassette.

Recombineering is a highly efficient DNA cloning and modification technique by using the recombinase-mediated homologous recombination. Selection/counterselection cassette is often used in chromosomal DNA or large episomal DNA manipulation, in which the selection marker is used for the first step cassette selection while deleting the target gene via allelic exchange, and the counterselection marker is used for the second step replacement of the cassette by the foreign DNA fragment. A variety of selection/counterselection cassettes are reported, however, the cassettes suffer from the shortcomings of the requirement of pre-engineered strain or specific culture medium. Herein, we report a novel S-tetR- PtetA-ccdB-aacC1-S selection/counterselection cassette that sidesteps the disadvantages. As a proof-of-concept, one-step gene cloning (0.7, 1.7, and 4.2 kb) and two-step Escherichia coli chromosomal gene knock-in (0.7 and 4.2 kb) were performed. The gene cloning and gene knock-in efficiencies are high up to 90%. The novel selection/counterselection cassette adds a powerful tool to the recombineering repertoire.

Investigation on many-body effects in micro-LEDs under ultra-high injection levels.

Micro-LEDs can work under an extremely high injection level and are widely used in high-brightness micro-displays and visible light communication. With the increase of carrier concentration, many-body effects gradually become important factors affecting devices' characteristics. Considering the effects of carrier scattering, bandgap renormalization, and Coulomb enhancement (CE), changes in the electroluminescence spectra of micro-LEDs are analyzed as the current density increases from 49.2 to 358.2 kA/cm2, the latter representing an ultra-high injection level. Affected by plasma screening, CE decreases below about 150 kA/cm2. After that, polarization screening dominates and effectively alleviates the spatial separation of electrons and holes, which results in CE increases to the maximum injection level of 358.2 kA/cm2. It is established that CE promotes radiative recombination processes. Different from the traditional phenomenon of "efficiency droop", the enhanced attraction between carriers leads to an abnormal increase of external quantum efficiency at high current density.

Enhanced light extraction efficiency of an LED package by a surface-mounted amorphous photonic structure.

In this study, we propose a low-cost, simple and feasible post-processing approach to improve the light extraction efficiency (LEE) of LED packages. Amorphous photonic structures (APSs) with only short-range order are fabricated from anodic aluminum oxide (AAO) and transferred to intermediate polymer stamp (IPS) by nanoimprint technology. The IPS with APSs is directly mounted onto the surface of an LED package, where the LEE is achieved as 94.6%. The scanning electron microscope (SEM) images of AAO templates and imprinted IPS are analyzed by radial distribution function and diameter histogram. The far-field patterns of APS-mounted LED packages are measured in electroluminescence (EL). The three-dimensional finite-difference time-domain (3D-FDTD) calculations of transmittance of APSs confirm that they improve the light extraction above the critical angle. Two-dimensional Fourier power spectra from SEM images of APSs are also calculated. The LEE enhancement is attributed to that the APSs have short-range order on a length scale comparable to emission wavelength of LED. We provide novel multistage simulations in a simplified FDTD model for the LED package. Finally, we discuss the influence of the morphology of APSs on the LEE of the APS mounted LEDs.

The Effect of Previous Irradiation for Patients With Prosthetic Breast Reconstruction: A Meta-Analysis.

BACKGROUND: Results regarding immediate prosthetic breast reconstruction after postmastectomy radiation therapy (PMRT) have been inconsistent. OBJECTIVES: The authors aimed to assess the efficacy and safety of PMRT before immediate prosthetic breast reconstruction for patients with breast cancer. METHODS: Electronic databases (PubMed, EmBase, and the Cochrane Library) were systematically searched to identify eligible studies from their inception until March 2020. The pooled odds ratio (OR) with 95% confidence intervals (CIs) was applied as an effect estimate and calculated using the random-effects model. RESULTS: Nineteen studies including a total of 6757 patients were selected for final meta-analysis. The pooled OR showed that PMRT was associated with a higher incidence of reconstruction failure (OR = 2.57; 95% CI =1.55-4.26; P < 0.001), capsular contracture (OR = 5.99; 95% CI = 3.12-11.47; P < 0.001), and overall complications (OR = 2.52; 95% CI = 1.68-3.79; P < 0.001). It was also associated with a lower incidence of patient satisfaction (OR = 0.29; 95% CI = 0.16-0.52; P < 0.001) and good aesthetic results (OR = 0.25; 95% CI = 0.12-0.52; P < 0.001) compared with those who did not undergo PMRT. These significant associations could be affected by study design, mean age, stage of immediate breast reconstruction, follow-up, and study quality. CONCLUSIONS: Although PMRT is the standard adjuvant therapy for mastectomy patients treated with immediate implant-based breast reconstruction, PMRT for patients undergoing immediate implant-based breast reconstruction has been associated with high risks of reconstruction failure, capsular contracture, and overall complications as well as low incidences of patient satisfaction and good aesthetic results.

Comparison of rapid freezing versus vitrification for human sperm cryopreservation using sucrose in closed straw systems.

Rapid freezing and vitrification using sucrose are two simple and cost-effective sperm cryopreservation methods. However, it is still unclear which method is better and what the optimal concentration of sucrose is. This study aimed to determine the optimal sucrose concentration for human sperm cryopreservation and compare the cryoprotective effects of rapid freezing versus vitrification using different closed straw systems in terms of sperm motility and DNA integrity. Our data showed that: (1) The optimal sucrose concentration for vitrification was 0.25 mol/l among the tested 0, 0.125, 0.25 and 0.5 mol/l concentrations; (2) Sperm total motility and progressive motility were cryopreserved significantly better by rapid freezing than vitrification in standard 0.5 ml cryostraws (P < 0.05); and (3) Sperm total motility and progressive motility were cryopreserved significantly better by vitrification in the straw-in-straw system than rapid freezing in the standard 0.5 cryostraw (P < 0.05), but no difference was found in sperm nuclear DNA fragmentation level between the two cryopreservation methods (P > 0.05). It was concluded that sucrose at 0.25 mol/l concentration is suitable for human sperm rapid freezing and vitrification, and sperm cryopreservation can be achieved by rapid freezing using closed standard 0.5 ml straws or by vitrification using the novel straw-in-straw system made of standard 0.25 and 0.5 ml straws.

Elliptically polarized laser-pumped Mx magnetometer towards applications at room temperature.

An atomic magnetometer operated with elliptically polarized light is investigated theoretically and experimentally. To explore the potential of this magnetometric configuration, the analytical form of the outgoing signal is derived. Parameters that significantly influence the performance are optimized, which lead to a sensitivity of 300 fT/Hz at 45 ∘C with a 2×2×2 cm uncoated Rb vapor cell. It is remarkable that a sensitivity of 690 fT/Hz is achieved at room temperature of 24 ∘C, which is improved by an order of magnitude compared with the conventional Mx magnetometer under its own optimized condition. The elliptically polarized approach offers attractive features for developing compact, low-power magnetometers, which are available without heating the uncoated vapor cell.

Radiomics on multi-modalities MR sequences can subtype patients with non-metastatic nasopharyngeal carcinoma (NPC) into distinct survival subgroups.

OBJECTIVES: To explore and evaluate the feasibility of radiomics in stratifying nasopharyngeal carcinoma (NPC) into distinct survival subgroups through multi-modalities MRI. METHODS: A total of 658 patients (training cohort: 424; validation cohort: 234) with non-metastatic NPC were enrolled in the retrospective analysis. Each slice was considered as a sample and 4863 radiomics features on the tumor region were extracted from T1-weighted, T2-weighted, and contrast-enhanced T1-weighted MRI. Consensus clustering and manual aggregation were performed on the training cohort to generate a baseline model and classification reference used to train a support vector machine classifier. The risk of each patient was defined as the maximum risk among the slices. Each patient in the validation cohort was assigned to the risk model using the trained classifier. Harrell's concordance index (C-index) was used to measure the prognosis performance, and differences between subgroups were compared using the log-rank test. RESULTS: The training cohort was clustered into four groups with distinct survival patterns. Each patient was assigned to one of the four groups according to the estimated risk. Our method gave a performance (C-index = 0.827, p < .004 and C-index = 0.814, p < .002) better than the T-stage (C-index = 0.815, p = .002 and C-index = 0.803, p = .024), competitive to and more stable than the TNM staging system (C-index = 0.842, p = .003 and C-index = 0.765, p = .050) in the training cohort and the validation cohort. CONCLUSIONS: Through investigating a large one-institutional cohort, the quantitative multi-modalities MRI image phenotypes reveal distinct survival subtypes. KEY POINTS: • Radiomics phenotype of MRI revealed the subtype of nasopharyngeal carcinoma (NPC) patients with distinct survival patterns. • The slice-wise analysis method on MRI helps to stratify patients and provides superior prognostic performance over the TNM staging method. • Risk estimation using the highest risk among slices performed better than using the majority risk in prognosis.

Correction to: Radiomics on multi-modalities MR sequences can subtype patients with non-metastatic nasopharyngeal carcinoma (NPC) into distinct survival subgroups.

The original version of this article, published on 14 March 2019, unfortunately contained a mistake.

TCR repertoire profiling of tumors, adjacent normal tissues, and peripheral blood predicts survival in nasopharyngeal carcinoma.

The T-cell immune responses in nasopharyngeal carcinoma patients have been extensively investigated recently for designing adoptive immunotherapy or immune checkpoint blockade therapy. However, the distribution characteristics of T cells associated with NPC pathogenesis are largely unknown. We performed deep sequencing for TCR repertoire profiling on matched tumor/adjacent normal tissue from 15 NPC patients and peripheral blood from 39 NPC patients, 39 patients with other nasopharyngeal diseases, and 33 healthy controls. We found that a lower diversity of TCR repertoire in tumors than paired tissues or a low similarity between the paired tissues was associated with a poor prognosis in NPC. A more diverse TCR repertoire was identified in the peripheral blood of NPC patients relative to the controls; this was related to a significant decrease in the proportion of high-frequency TCR clones in NPC. Higher diversity in peripheral blood of NPC patients was associated with a worse prognosis. Due to the peculiarity of the Vß gene usage patterns in the peripheral blood of NPC patients, 15 Vß genes were selected to distinguish NPC patients from controls by the least absolute shrinkage and selection operator analysis. We identified 11 clonotypes shared by tumors and peripheral blood samples from different NPC patients, defined as "NPC-associated" that might have value in adoptive immunotherapy. In conclusion, we here report the systematic and overall characteristics of the TCR repertoire in tumors, adjacent normal tissues, and peripheral blood of NPC patients. The data obtained may be relevant to future clinical studies in the setting of immunotherapy for NPC patients.

Investigation on strain relaxation distribution in GaN-based µLEDs by Kelvin probe force microscopy and micro-photoluminescence.

GaN/InGaN multi-quantum-wells (MQWs) micron light emitting diodes (µLEDs) with the size ranging from 10 to 300 µm are fabricated. Effects of strain relaxation on the performance of µLEDs have been investigated both experimentally and numerically. Kelvin probe force microscopy (KPFM) and micro-photoluminescence (µPL) are used to characterize the strained area on micron pillars. Strain relaxation and reducing polarization field in MQWs almost affects the whole mesa for 10 µm LEDs and about 4% area around the lateral for 300 µm LEDs. It makes a great contribution to high performance for smaller size µLEDs. Moreover, an indirect nanoscale strain measurement for µLEDs are provided.

Antimicrobial Susceptibility Evaluation and Multiple-Locus Variable Number Tandem Repeat Analysis of Neisseria gonorrhoeae Isolates in China in 2012.

OBJECTIVE: This study aimed to gain information on the antimicrobial susceptibility and molecular epidemiological typing of Neisseria gonorrhoeae (NG) isolates in China in 2012. METHODS: A total of 244 NG isolates were consecutively recovered from patients with uncomplicated gonorrhea attending sexually transmitted disease clinics in 3 Chinese cities-Guangzhou, Nanjing, and Tianjin-in 2012. Neisseria gonorrhoeae susceptibilities to penicillin and tetracycline were examined by detecting penicillinase-producing NG (PPNG) and high-level tetracycline-resistant NG, and NG susceptibilities to ciprofloxacin, spectinomycin, ceftriaxone, and cefixime were determined using an agar dilution method. Neisseria gonorrhoeae isolates were typed by multiple-locus variable number tandem repeat analysis. We conducted a χ analysis to compare clusters with Bonferroni correction and Kruskal-Wallis test. RESULTS: Neisseria gonorrhoeae isolates gathered from the 3 cities differed significantly in the prevalence of tetracycline-resistant NG (P < 0.001) and NG treated with ceftriaxone with a minimum inhibitory concentration of 0.125 mg/L or higher (P < 0.001). The analysis of the combination of the 7 variable number of tandem repeats loci for all of the 244 isolates yielded 110 multiple-locus variable number tandem repeat analysis types falling into 5 clusters. Cluster III was associated with PPNG, whereas cluster II was associated with non-PPNG (P < 0.05) and NG treated with ceftriaxone with a minimum inhibitory concentration of 0.125 mg/L or higher (P < 0.05). CONCLUSIONS: Antimicrobials that can be used with confidence to treat NG infection currently in China include ceftriaxone and spectinomycin, but not penicillin, tetracycline, ciprofloxacin, and cefixime. Moreover, some of the resulting clusters were associated with PPNG and NG with decreased ceftriaxone susceptibility.

Fabrication, characterization and applications of flexible vertical InGaN micro-light emitting diode arrays.

Flexible vertical InGaN micro-light emitting diode (micro-LED) arrays have been fabricated and characterized for potential applications in flexible micro-displays and visible light communication. The LED epitaxial layers were transferred from initial sapphire substrates to flexible AuSn substrates by metal bonding and laser lift off techniques. The current versus voltage characteristics of flexible micro-LEDs degraded after bending the devices, but the electroluminescence spectra show little shift even under a very small bending radius 3 mm. The high thermal conductivity of flexible metal substrates enables high thermal saturation current density and high light output power of the flexible micro-LEDs, benefiting the potential applications in flexible high-brightness micro-displays and high-speed visible light communication. We have achieved ~40 MHz modulation bandwidth and 120 Mbit/s data transmission speed for a typical flexible micro-LED.

Comparing survival curves based on medians.

BACKGROUND: Although some nonparametric methods have been proposed in the literature to test for the equality of median survival times for censored data in medical research, in general they have inflated type I error rates, which make their use limited in practice, especially when the sample sizes are small. METHODS: In this paper, we propose a new nonparametric test with a simple test statistic to compare median survival times. RESULTS: The results from our comprehensive simulation study show the new test controls type I error rate very well under all situations considered, even for small sample sizes. In addition, it has comparable detecting power compared to existing methods. Another advantage of the proposed test is its relatively simple formula that requires less computation. CONCLUSIONS: We propose a new statistical method for comparing survival curves based on their medians. The new method can be easily implemented and applied to censored event time data.

Endogenous animal toxin-like human ß-defensin 2 inhibits own K(+) channels through interaction with channel extracellular pore region.

Human potassium channels are widely inhibited by peptide toxins from venomous animals. However, no human endogenous peptide inhibitor has been discovered so far. In this study, we demonstrate for the first time using electrophysiological techniques, that endogenous human ß-defensin 2 (hBD2) is able to selectively and dose-dependently inhibit the human voltage-gated Kv1.3 channel at picomolar peptide concentration. The co-immunoprecipitation assays further supported the selective binding of hBD2 to Kv1.3 channel. Using mutagenesis experiments, we found that the outer pore domain of Kv1.3 channel was the binding site of hBD2, which is similar to the interacting site of Kv1.3 channel recognized by animal toxin inhibitors. The hBD2 was able to suppress IL-2 production through inhibition of Kv1.3 channel currents in human Jurkat cells, which was further confirmed by the lack of hBD2 activity on IL-2 production after Kv1.3 knockdown in these cells. More interestingly, hBD2 was also found to efficiently inhibit Kv1.3 channel currents and suppress IL-2 production in both human primary CD3(+) T cells and peripheral mononuclear cells from either healthy donors or psoriasis patients. Our findings not only evidenced hBD2 as the first characterized endogenous peptide inhibitor of human potassium channels, but also paved a promising avenue to investigate newly discovered function of hBD2 as Kv1.3 channel inhibitor in the immune system and other fields.

Cutaneous infections caused by rapidly growing mycobacteria: case reports and review of clinical and laboratory aspects.

Skin and soft tissue infections caused by rapidly growing non-tuberculous mycobacteria (RG-NTM) have become a growing clinical concern over the past decades. These RG-NTM are ubiquitous environmental organisms and most are resistant to traditional antituberculous agents. In this report, we describe 3 cutaneous infections caused by RG-NTM, namely, Mycobacterium abscessus, M. chelonae, and M. conceptionense, and present the clinical and laboratory characteristics of these infections.

Prognostic value of grading masticator space involvement in nasopharyngeal carcinoma according to MR imaging findings.

PURPOSE: To derive a suitable method for grading masticator space invasion in nasopharyngeal carcinoma on the basis of magnetic resonance (MR) images and to determine its prognostic value in patients undergoing intensity-modulated radiation therapy. MATERIALS AND METHODS: After institutional review board approval and informed consent were acquired, 808 patients with nasopharyngeal carcinoma who were treated with definitive intensity-modulated radiation therapy were analyzed retrospectively. The anatomic sites of masticator space involvement were identified with MR imaging. Overall survival, local relapse-free survival, and distant metastasis-free survival were calculated by using the Kaplan-Meier method and were compared by using the log-rank test. Potential prognostic factors were identified by means of multivariate analysis. RESULTS: Masticator space involvement was diagnosed in 163 of 808 patients (20.2%). Patients with lateral invasion (involvement of the lateral pterygoid muscle of the masticator space and beyond) had significantly poorer overall survival and distant metastasis-free survival than those with medial invasion (involvement of the medial pterygoid muscle of the masticator space) (P = .035 and P = .026, respectively). Furthermore, their overall survival, local relapse-free survival, and distant metastasis-free survival were significantly poorer compared with patients with stage T2 or T3 disease (all P ≤ .023) but similar to patients with stage T4 disease. The grade of masticator space involvement was an independent prognostic factor for overall survival, local relapse-free survival, and distant metastasis-free survival (all P ≤ .023). CONCLUSION: Masticator space involvement in nasopharyngeal carcinoma should be graded as medial (stage T2 disease) or lateral (stage T4 disease). This can facilitate staging of nasopharyngeal carcinoma and may be a suitable prognostic indicator of survival.