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Diabetic kidney disease (DKD) is the most common complication of type 2 diabetes mellitus (T2DM), and its pathogenesis is not yet fully understood and lacks noninvasive and effective diagnostic biomarkers. In this study, we performed urine metabolomics to identify biomarkers for DKD and to clarify the potential mechanisms associated with disease progression.We applied a liquid chromatography-mass spectrometry-based metabolomics method combined with bioinformatics analysis to investigate the urine metabolism characteristics of 79 participants, including healthy subjects (n = 20), T2DM patients (n = 20), 39 DKD patients that included 19 DKD with microalbuminuria (DKD + micro) and 20 DKD with macroalbuminuria (DKD + macro).Seventeen metabolites were identified between T2DM and DKD that were involved in amino acid, purine, nucleotide and primarily bile acid metabolism. Ultimately, a combined model consisting of 2 metabolites (tyramine and phenylalanylproline) was established, which had optimal diagnostic performance (area under the curve (AUC) = 0.94). We also identified 19 metabolites that were co-expressed within the DKD groups and 41 metabolites specifically expressed in the DKD + macro group. Ingenuity pathway analysis revealed three interaction networks of these 60 metabolites, involving the sirtuin signaling pathway and ferroptosis signaling pathway, as well as the downregulation of organic anion transporter 1, which may be important mechanisms that mediate the progression of DKD.This work reveals the metabolic alterations in T2DM and DKD, constructs a combined model to distinguish them and delivers a novel strategy for studying the underlying mechanism and treatment of DKD.

Di(2-ethylhexyl) phthalate (DEHP) is a common environmental pollutant with renal and reproductive toxicity. Lycium barbarum glycopeptide (LbGp) is the main active component of Lycium barbarum, which can protect the kidney and promote reproduction. Autophagy and apoptosis are the regulatory mechanisms of cell adaptation to external stress. This study investigated whether DEHP and LbGp affect kidney and testis by regulating autophagy and apoptosis. DEHP induced apoptosis in human embryonic kidney-293 (HEK-293) cells and human kidney-2 (HK-2) cells, as well as glomerular enlargement, enhanced renal autophagy and inflammation, decreased testicular germ cells, and enhanced testicular autophagy. LbGp reduced apoptosis in HEK-293 cells and HK-2 cells, reduced glomerular enlargement and renal inflammation, enhanced renal autophagy, increased testicular germ cells, and alleviated testicular autophagy. These results suggested that DEHP induced inflammation to cause kidney injury, mildly enhanced renal autophagy, and also induced excessive autophagy, leading to testicular injury. LbGp reduced inflammation and appropriately enhanced autophagy to alleviate renal injury and also reduced excessive autophagy to alleviate testicular injury. Silent information regulator 1 (SIRT1)/forkhead box O3a (FoxO3a)-mediated autophagy and p38 mitogen-activated protein kinase (p38 MAPK)-mediated inflammation played important roles.

Oxidative stress plays the main role in the pathogenesis of diabetes mellitus and peripheral neuropathy. Polydatin (PD) has been shown to exhibit strong antioxidative and antiinflammatory effects. At present, no research has focused on the possible effects of PD on Schwann cells and impaired peripheral nerves in diabetic models. Here, we used an in vitro Schwann cell damage model induced by methylglyoxal and an in vivo diabetic sciatic nerve crush model to study problems in such an area. In our experiment, we demonstrated that PD potently alleviated the decrease of cellular viability, prevented reactive oxygen species generation, and suppressed mitochondrial depolarization as well as cellular apoptosis in damaged Schwann cells. Moreover, we found that PD could upregulate Nrf2 and Glyoxalase 1 (GLO1) expression and inhibit Keap1 and receptor of AGEs (RAGE) expression of damaged Schwann cells. Finally, our in vivo experiment showed that PD could promote sciatic nerves repair of diabetic rats. Our results revealed that PD exhibited prominent neuroprotective effects on Schwann cells and sciatic nerves in diabetic models. The molecular mechanisms were associated with activating Nfr2 and GLO1 and inhibiting Keap1 and RAGE.

To explore and evaluate the long-term effects of diverse online teaching methods to minimize the negative influences of online teaching of basic courses in clinical medicine during the COVID-19 pandemic. Forty-nine students in grade 2017 majoring in clinical medicine (five-year program) were enrolled in this study (study group). They received online teaching of six basic clinical courses, including diagnostics, basic clinical skills, general surgery, medical imaging, and doctor‒patient communication, from March to July 2020. The study first introduced the process of online teaching, especially basic clinical skills such as history taking, physical examination, internal punctures, electrocardiography and so on. Then, they reviewed the schedules to reinforce these skills when the students returned to school. The final exam scores of four clinical courses, including internal medicine, surgery, obstetrics and gynaecology, and paediatrics, and the scores of graduation examinations were used to evaluate the long-term effects of online teaching. These scores were compared with students in grade 2014 who learned through offline teaching (control group). After graduation examinations, questionnaires were distributed to understand the influence of online teaching on learning clinical courses, internships and postgraduate entrance examinations. The results showed that the scores of internal medicine part I and surgery part II in the study group were higher than those in the control group, and the differences were statistically significant (P < 0.05). Differences were not statistically significant in scores of internal medicine part II, surgery part I, obstetrics and gynaecology, and paediatrics between the two groups (P > 0.05). Two students postponed graduation in grade 2017, so 47 students took part in the graduation examination. The scores for knotting, dressing change, and cardiopulmonary resuscitation in the study group were significantly lower than those in the control group (P < 0.05). For the three items internal punctures, four-step palpation in obstetrics, and assessment of children's growth and development, the scores in the study group were higher than those in the control group, and the differences were statistically significant (P 0.05). All 47 participants in the study group completed the questionnaire survey, with a response rate of 100%. Twenty students thought that the online learning experience had a great influence on learning clinical courses such as internal medicine, surgery, obstetrics and gynaecology and paediatrics, whereas 27 students thought it had a slight influence. There were 23 students who thought online learning had a great influence and 24 students who thought it had a slight influence when attending the internship qualification examination. Thirteen students thought that the influence on the internship was great, 30 students thought it was slight, and 4 thought that online learning had no influence. Regarding which course had the most influence on the internship, 36 students thought it was diagnostics, 7 students thought it was general surgery, and 3 students thought it was other courses. Among the 40 students who participated in the entrance examination for a master's degree, 2 thought the online learning experience had a great influence, 19 thought it had a slight influence, and 11 students thought it had no influence. Among the six courses that influenced the re-examination for postgraduate students, 16 students thought the most influential course was diagnostics, 5 students chose general surgery, and 1 student thought it was another course. Exploration of diverse online teaching methods is helpful and successful for mastering clinical knowledge. However, online teaching had a great influence on some basic clinical skills that require more practice. The strategy used to reinforce these skills after returning to school makes up for the shortage of these practical skills in online courses to a certain extent.

Calponin 3 (CNN3) is known to serve a role in certain types of cancer, such as gastric cancer and colorectal cancer. The present study investigated the clinical significance of CNN3 in non-small cell lung cancer (NSCLC) by evaluating its expression profile and relationship with disease prognosis using the Gene Expression Omnibus repository, Gene Expression Profiling Interactive Analysis 2 (GEPIA2) and Kaplan-Meier plotter analysis. CNN3 mRNA expression was measured using reverse transcription-quantitative PCR, while the protein expression level was measured using western blot analysis. Cell proliferation, cell cycle and apoptosis, and migration and invasion were analyzed using MTS assay, flow cytometry and Transwell assays, respectively. These results revealed that CNN3 mRNA expression was downregulated in NSCLC tissues compared with that in normal tissues. Additionally, CNN3 expression had a high diagnostic value based on the GSE2514 dataset and the data from The Cancer Genome Atlas and the Genotype Tissue Expression database, whereas it had a low diagnostic value based on the GSE10072 dataset. Furthermore, CNN3 expression was associated with survival in patients with lung adenocarcinoma (LUAD), whereas it was not associated with survival in patients with lung squamous cell carcinoma (LUSC) according to the Kaplan-Meier plotter results. According to the data from GEPIA2, and the GSE72094, GSE41271 and GSE31210 datasets, CNN3 expression was not associated with the prognosis of patients with LUAD and LUSC. The mRNA and protein expression levels of CNN3 were lower in two NSCLC cell lines (A549 and SK-MES-1) than in a human bronchial epithelial cell line (BEAS-2B). CNN3 overexpression suppressed cell proliferation, migration and invasion, induced G1-phase arrest, promoted apoptosis and suppressed PI3K/AKT signaling pathway activation in the NSCLC cell lines, whereas CNN3 overexpression had no effect on cell morphology. In conclusion, CNN3 suppressed the proliferation and metastasis of NSCLC cells by downregulating the PI3K/AKT signaling pathway, making it a potential therapeutic target in this disease.

Recent studies showed that macrophages co-cultured with ovarian cancer stem-like cells (OCSLCs) induced SKOV3 cell stemness via IL-8/STAT3 signaling. Genistein (GEN) demonstrates chemopreventive activity in inflammation-associated cancers. The present study aimed to examine whether and if GEN inhibits the stemness of SKOV3 and OVCA-3R cells induced by co-culture of THP-1 macrophages and SKOV3-derived OCSLCs. The co-culture was treated with or without different concentrations (10, 20, and 40 μmol/L) of GEN for 24 h. Depletion or addition of IL-8 in Co-CM and knockdown or overexpression of STAT3 in THP-1 macrophages was performed to demonstrate the possible associated mechanisms. The combined effects of GEN and STAT3 knockdown were examined with the nude mouse modle by co-injection of SKOV3-derived OCSLCs with THP-1 macrophages. Our results showed that GEN down-regulated CD163 and p-STAT3 expression of THP-1 macrophage, decreased the levels of IL-10, increased the levels of IL-12 and nitric oxide (NO) in the conditioned medium, and reduced the clonogenic and sphere-forming capacities and the expression of CD133 and CD44 in SKOV3 cells induced by co-culture of THP-1 macrophages and OCSLCs in a dose-dependent manner. Moreover, depletion or addition of IL-8 enhanced or attenuated the effect of GEN. Additionally, knockdown or overepression of STAT3 in THP-1 macrophages potentiated or attenuated the inhibitory effects of GEN. Importantly, STAT3 overexpression retrieved the effects of IL-8 combined with GEN depletion on M2 polarization of THP-1 macrophages and stemness of SKOV3 cells induced by co-culture. The combination of GEN and STAT3 knockdown cooperatively inhibited the growth of tumors co-inoculated with OCSLCs/THP-1 macrophages in nude mice in vivo through blocking IL-8/STAT3 signaling. In summary, our findings suggested that GEN can inhibit the increased M2 polarization of macrophages and stemness of ovarian cancer cells by co-culture of macrophages with OCSLCs through disrupting IL-8/STAT3 signaling axis. This assisted GEN to be as a potential chemotherapeutic agent in human ovarian cancer.

The pathogenesis and cisplatin chemoresistance of ovarian cancer (OC) are still unclear. Vacuolar protein sorting‐associated 33B (VPS33B) has not been reported in OC to date. In this study, immunohistochemistry was used to detect VPS33B protein expression between OC and ovarian tissues. MTT, EdU, colony formation, cell cycle, in vivo tumorigenesis, western blot, ChIP, EMSA, co‐immunoprecipitation (CoIP), qRT‐PCR, and microconfocal microscopy were used to explore the function and molecular mechanisms of VPS33B in OC cells. The results of the present study demonstrated that VPS33B protein expression was obviously reduced in OC compared with that in ovarian tissues. Overexpressed VPS33B suppressed cell cycle transition, cell growth, and chemoresistance to cisplatin in vitro and in vivo. Analysis of the mechanism indicated that overexpressed VPS33B regulated the epidermal growth factor receptor (EGFR)/PI3K/AKT/c‐Myc/p53/miR‐133a‐3p feedback loop and reduced the expression of the cell cycle factor CDK4. Nasopharyngeal epithelium‐specific protein 1 (NESG1) as a tumor suppressor not only interacted with VPS33B, but was also induced by VPS33B by the attenuation of PI3K/AKT/c‐Jun‐mediated transcription inhibition. Overexpressed NESG1 further suppressed cell growth by mediating VPS33B‐modulated signals in VPS33B‐overexpressing OC cells. Finally, NESG1 induced VPS33B expression by reducing the inhibition of PI3K/AKT/c‐Jun‐mediated transcription. Our study is the first to demonstrate that VPS33B serves as a tumor suppressor, and VPS33B can interact with NESG1 to suppress cell growth and promote cisplatin sensitivity by regulating the EGFR/PI3K/AKT/c‐Myc/p53/miR‐133a‐3p feedback loop in OC cells., VPS33B can interacts with NESG1 to suppress cell growth and promote cisplatin sensitivity by regulating the EGFR/PI3K/AKT/c‐Myc/p53/miR‐133a‐3p feedback loop in OC cells.

Background: The prognosis of Epithelial Ovarian Cancer (EOC) is poor, but the prognostic biomarkers are neither sensitive nor specific. Therefore, it is very important to search novel prognostic biomarkers for EOC. Objectives: The present study aimed to investigate Myosin Light Chain 9(MYL9) expression in Epithelial Ovarian Cancer (EOC) tissues (including paraffin-embedded and fresh tissue samples) and its relationship with clinicopathological characteristics, as well as its potential prognostic value in patients with EOC. Methods: Between March 2009 and December 2018, all of 184 paraffin-embedded cancer tissues from patients with EOC and 41 paratumor tissues, pathologically confirmed at the Memorial Hospital of Sun Yat-sen University and Integrated Hospital of Traditional Chinese Medicine, Southern Medical University, were collected for the present study and were assessed for MYL9 protein expression patterns using Immunohistochemistry (IHC). Furthermore, from August 2013 to November 2019, 16 fresh EOC tissues and their paired paratumor tissues, pathologically confirmed at the Integrated Hospital of Traditional Chinese Medicine, Southern Medical University were analyzed using Reverse-Transcription Quantitative PCR (RT-qPCR) to detect MYL9 mRNA expression levels. Results: The results showed that MYL9 expression was higher in cancer tissues compared with that in paratumor tissues, and MYL9 overexpression was associated with shorter Recurrence Free Survival (RFS) and Overall Survival (OS) of EOC patients. Furthermore, multivariate Cox model analysis indicated that MYL9 overexpression was an independent poor survival prediction in patients with EOC. Conclusion: MYL9 is upregulated in EOC and may serve as a useful patent of prognostic biomarker in EOC, and it may demonstrate an important value for the clinical treatment and supervision of patients with EOC.

Arthritis remains the notion of a hard-to-treat disease that raises an area of unmet clinical need. The phytomedicine tripterine (Tri) and trace element selenium (Se) have been shown to be of anti-inflammatory activity. This study was devoted to develop nanomedicine containing Tri and Se used for fighting against arthritis via a coordination mechanism. Se-deposited Tri phytosomes (Se@Tri-PTs) were prepared by a melting-hydration/in situ reduction technique and characterized by particle size, ζ potential, morphology, and entrapment efficiency (EE). The resultant Se@Tri-PTs were 126 nm around in particle size with an EE of 98.85%. Se@Tri-PTs exhibited a sustained drug release both in 0.1 M HCl and pH 6.8 PBS compared with Se-free phytosomes (Tri-PTs). The in vivo antiarthritic test demonstrated that Se@Tri-PTs could result in significant resolution of arthritis and decline of inflammatory factors. Phytosomes primely facilitated the transepithelial transport of Tri, while Se enhanced the antiarthritic efficacy of the phytomedicine synergistically. The present work provides a proof-of-concept for the combined therapy of arthritis using Tri and Se in the form of nanoparticles.

Our research aimed to build allogeneic artificial conduits with epimysium and muscle-derived stem cells (MDSCs) from the skeletal muscle of mice. We applied the conduit to repair peripheral nerve defects and estimated the effectiveness of the repair process. In the research, we prepared epimysium conduits with lumens to bridge repair a 5-mm-long sciatic nerve defect from C57 wild-type mice and then transplanted green fluorescent protein (GFP)-MDSCs and Matrigel suspensions into the conduit. Histological and functional assessments were performed 4 and 8 weeks after surgery. The tissue-engineered conduit from muscle effectively repaired the nerve defect, while the group with GFP-MDSCs showed improved histological examinations and functional assessments, and the newborn nerves highly expressed GFP. As the results suggested, autologous epimysium conduits represent a reliable method to repair peripheral nerve defects, and the addition of MDSCs promote the effectiveness of differentiating into multiple lineages. Our research simultaneously demonstrated the myogenic, neurogenic, and angiogenic potential of MDSCs in vivo for the first time.

Background Recent studies showed that macrophages co-cultured with ovarian cancer stem-like cells (OCSLCs) induced SKOV3 cell stemness via IL-8/STAT3 signaling. Genistein (GEN) demonstrates chemopreventive activity in inflammation-associated cancers. The present study aimed to examine whether and if GEN inhibits the stemness of SKOV3 and OVCA-3R cells induced by co-culture of THP-1 macrophages and SKOV3-derived OCSLCs. Methods The co-culture was treated with or without different concentrations (10, 20, and 40 μmol/L) of GEN for 24 h. Depletion or addition of IL-8 in Co-CM and knockdown or overexpression of STAT3 in THP-1 macrophages was performed to demonstrate the possible associated mechanisms. The combined effects of GEN and STAT3 knockdown were examined with the nude mouse modle by co-injection of SKOV3-derived OCSLCs with THP-1 macrophages. Results Our results showed that GEN down-regulated CD163 and p-STAT3 expression of THP-1 macrophage, decreased the levels of IL-10, increased the levels of IL-12 and nitric oxide (NO) in the conditioned medium, and reduced the clonogenic and sphere-forming capacities and the expression of CD133 and CD44 in SKOV3 cells induced by co-culture of THP-1 macrophages and OCSLCs in a dose-dependent manner. Moreover, depletion or addition of IL-8 enhanced or attenuated the effect of GEN. Additionally, knockdown or overepression of STAT3 in THP-1 macrophages potentiated or attenuated the inhibitory effects of GEN. Importantly, STAT3 overexpression retrieved the effects of IL-8 combined with GEN depletion on M2 polarization of THP-1 macrophages and stemness of SKOV3 cells induced by co-culture. The combination of GEN and STAT3 knockdown cooperatively inhibited the growth of tumors co-inoculated with OCSLCs/THP-1 macrophages in nude mice in vivo through blocking IL-8/STAT3 signaling. Conclusions In summary, our findings suggested that GEN can inhibit the increased M2 polarization of macrophages and stemness of ovarian cancer cells by co-culture of macrophages with OCSLCs through disrupting IL-8/STAT3 signaling axis. This assisted GEN to be as a potential chemotherapeutic agent in human ovarian cancer.

OBJECTIVE: To investigate the effect of cells in the epimysium conduit (EMC) on the regeneration of sciatic nerve of mice. METHODS: The epimysium of the 8-week-old male C57BL/6J enhanced green fluorescent protein (EGFP) mouse was trimmed to a size of 5 mm×3 mm, and prepared in a tubular shape (ie, EMC). Some epimysia were treated with different irradiation doses (0, 15, 20, 25, 30, 35 Gy) to inhibit cells migration. Then the number of migrating cells were counted, and the epimysia with the least migrating cells were selected to prepare EMC. Some epimysia were subjected to decellularization treatment and prepared EMC. HE and Masson staining were used to identify the decellularization effect. Twenty-four C57BL/6J wild-type mice were used to prepare a 3-mm-long sciatic nerve defect of right hind limb model and randomly divided into 3 groups (n=8). EMC (group A), EMC after cell migration inhibition treatment (group B), and decellularized EMC (group C) were used to repair defects. At 16 weeks after operation, the midline of the regenerating nerve was taken for gross, toluidine blue staining, immunofluorescence staining, and transmission electron microscopy. RESULTS: At 15 days, the number of migrating cells gradually decreased with the increase of irradiation dose. There was no significant difference between 30 Gy group and 35 Gy group (P>0.05); there were significant differences between the other groups (P0.05). CONCLUSION: The cellular components of the epimysium participate in and promote the regeneration of the sciatic nerve in mice.

Dual-band or multi-band RF power amplifiers (PAs) have attracted a lot of attention in recent years as they rise to the challenge of segmented spectrum allocation in wireless systems. Adaptive digital predistortion (DPD) for concurrent dual-band PAs evolves from existing DPD for single-band PAs. In this paper, we derive the baseband dual-band Volterra model from the corresponding passband model. In addition, the computational complexity of the DPD estimation algorithm increases dramatically as the number of coefficients for dual-band DPD is much larger than that for single-band DPD. In this paper, we propose a low complexity DPD coefficient estimation algorithm for concurrent dual-band PAs based on polar decomposition of the general Volterra model. By dividing complex-valued coefficient estimation into amplitude estimation and phase estimation separately, the proposed algorithm achieves at most 75% computational complexity reduction. Moreover, the proposed algorithm can achieve similar performance with the conventional coefficient estimation method. Simulation and measured results validate performance of the proposed algorithm for a solid-state PA.

Owing to the complicated and time-consuming regenerative process, the repair of injured peripheral nerves depends largely on ongoing stem-cell therapy. Decades ago, researchers successfully isolated and identified muscle-derived stem cells (MDSCs) and discovered their potential for multidifferentiation. MDSCs play an important role in trauma repair associated with neuromuscular and vascular injury by simultaneously promoting tissue regrowth via direct differentiation and systematic secretion under physiological conditions. However, the isolation, culture, induction and application of MDSCs require further methodological analysis before clinical application. In this review, we comprehensively discuss the challenges associated with neural regeneration and reviewed the progress of stem cell based regenerative medicine, in an effort to realize the potential of MDSCs in nerve regeneration.

Transmission signals of modern communication systems, such as orthogonal frequency-division multiplexing signals, usually have large peak-to-average power ratio. These signals are sensitive to the power amplifier's nonlinearity, which generates both in-band distortion and out-of-band spectral regrowth. The adaptive digital predistortion (DPD) is an efficient linearization technique without sacrificing the power efficiency. To estimate the DPD coefficients, numerical instability and computational complexity are bottlenecks. In this paper, we propose a general approach to derive orthonormal basis functions, which can improve the numerical stability during the coefficients estimation. By applying the orthonormal basis functions, we further propose an adaptive algorithm that exhibits a low computation complexity of least mean squares algorithm while retaining the fast convergence speed of recursive least squares algorithm. Both simulation and experimental results validate the effectiveness of the proposed algorithm.

Volterra model or memory polynomial model are commonly used to describe the nonlinearity with memory effects for power amplifier (PA) modeling as well as digital predistorter designs. Different monomial terms of the Volterra model or memory polynomial model are highly correlated, which become a challenge during the fixed-point implementation of the coefficients estimation as the data matrix is ill-conditioned. Previous works derived orthogonal basis functions to eliminate the correlation among different monomial terms. Conversely, models of the PAs or the digital predistorters work in the oversampled domain to capture the adjacent band and/or out of band emissions. The correlation among data samples, which was neglected in previous works, can also be a major issue to the numerical instability in the coefficients estimation. In this article, we propose a set of new orthonormal basis functions to eliminate the correlation among different monomial terms as well as the correlation among data samples. As the proposed orthonormal basis functions can be predetermined and implemented with look up tables, the fixed-point implementation is feasible and online computational complexity is greatly reduced. Simulation and experimental results show that the proposed orthonormal basis functions outperform the conventional ones in terms of condition number reduction as well as spectral regrowth suppression. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:202–212, 2015.

Nanocrystalline (La 1− x Eu x ) 2 Zr 2 O 7 series solid solutions were prepared by a simple and controllable salt-assisted combustion process. The samples were characterized by XRD, TEM and EDS. The results showed the partial substituted products were single-phase solid solutions. The effect of thermal treatment temperature on the crystal size of nanocrystals and the activation energy of crystal growth during calcinations were studied. And the activation energy of (La 1− x Eu x ) 2 Zr 2 O 7 series with x = 0.05, 0.1, 0.25, 0.5, and 0.75 was 25.4, 27.8, 28.0, 32.4, and 30.6 kJ/mol, respectively. TEM images revealed that the products were composed of well-dispersed cubic-like particles with the range of size at 20–50 nm. EDS results furtherly confirmed that the composition of the obtained compound was in agreement with the stiochiometric formular. The emission spectra of (La 1− x Eu x ) 2 Zr 2 O 7 nanocrystals at 385 nm upon excitation showed that there were some intense and prevailing emission peaks located at 590–650 nm.

LED performance characteristics under dc regulation modes have been studied extensively. But limited literatures are dedicated to studies of LED performance characteristics under different ac regulation modes. With direct ac powering LEDs for lighting application being available and more attractive in efficiency due to the elimination of ac-dc converter, investigation of the influence of different ac current regulation modes on LED performance characteristics becomes important and essential. This paper presents an experimental investigation of different current regulation modes on LED light output with different LED connection configurations. It is found certain current regulation mode under which a higher light output with the same absolute average current can be obtained. The result is due to facts that the absolute average current is the measurement of electrons and holes recombination rate inside the LED, and second-order nonlinear effect and thermal issue lead to the different light output for different ac regulation modes.

The chemical structures of unsaturated, wax-oxidation-produced, synthetic straight-chain C5–-C9 fatty acids greatly affect the neopentylpolyol ester esterification rate, and the color, viscosity and thermal oxidation stability of the ester. The effects are very different with the various double-bond positions in the unsaturated fatty acid portion of the ester molecules. This paper discusses the important relationships between the ester properties, the most important being the stability of the esters and the composition of the fatty acid used in the esterification. It offers a useful reference for researching neopentylpolyol esters (NPEs) of fatty acids in order to improve the quality of synthetic ester lubricants, especially aircraft gas turbine engine lubricants, in which NPE is usually used as the basestock. Presented at the 51 st Annual Meeting in Cincinnati, Ohio May 19–23, 1996

High power LEDs for lighting application can be implemented with dies. Multiple LEDs are usually connected in series to sustain high power supply voltage like AC 110V due to low LED forward voltage. AC-DC converter is often required for LED arrays working under an AC power supply. But the AC-DC converter brings power consumption overhead and degrades the overall system efficiency as much as 15%. In this work, a high power ceramic COB (Chip On Board) LED array packaging technology capable of working under AC 110V is developed. A total of 40 LEDs are used in the ceramic COB LEDs array to allow it work directly under AC 110V power supply. A special powering method is designed and dedicated to the COB LED array. The special powering method ensures both high light output and high LEDs array reliability especially under supply voltage variations. The measured COB LEDs current vs. AC supply voltage variation is shown in Fig.1 An extremely high driving efficiency (>98%) at the max power and a high power factor are achieved due to the elimination of the AC-DC converter. The electrical efficiency over LEDs forward current is plotted in Fig.2. The structure and top view of COB LED packaging is shown in Fig.3 and Fig.4. The COB package dimension is 68mm by 28mm. With 150mA LEDs forward current, the measured total power is 20W. The max LEDs forward current for this design is 700mA and the max power is 95W. The cross section of the PCB design is shown in Fig.5. Since AC-DC converter reliability is becoming the bottleneck of the high power LED lighting system, the presented ceramic COB LEDs array package with the special powering circuit reliability is enhanced due to the elimination of AC-DC converter. The system reliability is performed and shown in Fig.6. There is no performance degradation of both the ceramic COB LED and control circuit for 1000 hours. Long term reliability test of the system is still under testing and will be presented.

Multiple-input multiple-output (MIMO) techniques have been extensively used in modern wireless communications. The front-end nonlinearity coupled with crosstalk in a MIMO transmitter is much more complex than that in a single-input single-output (SISO) system. In this paper, we propose a nonlinear crosstalk calibration algorithm with the corresponding reference signal design. We start with the nonlinear crosstalk model of the MIMO transmitter and derive its corresponding inverse compensation model. The proposed model characterizes the nonlinearity and the crosstalk in separated blocks. We then propose specifically designed reference signals that utilize the model structure. The nonlinear crosstalk model can be reorganized and simplified with the reference signal. Thus, the complexity of the model coefficients estimation is greatly reduced without compromising the model accuracy. In addition, with the proposed algorithm, the compensation of the nonlinearity and crosstalk can be done separately. Simulations show a satisfactory calibration results with low computational complexity.

This paper reports the design, fabrication and simulation of a novel array of micromachined electrodes with different lengths for use in auditory nerve prostheses. A 10 x 10 array is created in a 1 mm2 on silicon with bulk micromachining technology. The electrode lengths vary from 200 microm to 400 microm. This design could provide access to most fascicles within the auditory nerve and thus allow stimulation of a broad tonotopic range within the nerve fiber. A multichannel ultra-low power circuit is also designed, fabricated, and tested for neural signal recording. The chip is fabricated in 0.5 microm AMI CMOS technology with a die size of 1.5 mm x 1.5 mm. The total power consumption is less than 100 microW.

This paper presents a new switched supply tunable red-green-blue (RGB) light emitting diode (LED) driver. The RGB LEDs act not only as light emitting devices but also as rectifying diodes in the presented driver circuit. The RGB LED color control is realized by controlling the switched supply voltage amplitude, frequency, and duty cycle. The driver efficiency is high since the only loss in the driver circuit is the switch and can be further reduced by direct alternate current supply.

A new type of drivers for light emitting diodes (LEDs) is introduced based on the switched-capacitor frequency modulation. In contrast to conventional constant dc current drivers, the current pulse is provided by this new switched-capacitor LED driver. In the present driver, the charging capacitor is charged and discharged through a LED and the current flow direction is controlled by a metal oxide semiconductor switch. The input current (and thus the LED brightness) is proportional to the switch clock frequency at relatively low frequencies and becomes saturated at relatively high frequencies. This new driver circuit is simple and robust and maintains high efficiency for a wide range of input powers. In addition, the dimming control is easily realized by modulating clock frequency. Finally, this LED driver consumes no dc current and thus provides inherent protection to LED in standby mode.