Osteochondral explants for diarthrodial joint diseases: bridging the gap between bench and bedside.

Diarthrodial joint diseases, affecting hundreds of millions of people worldwide, mainly include osteoarthritis and cartilage injuries. No consensus on joint disease models has been achieved so far owing to the complex aetiologies, pathophysiological mechanisms and heterogeneity of disorders. The disease models established using isolated chondrocytes or small animals have the weaknesses of lacking native extracellular matrix and inter-species differences in anatomical and biomechanical cartilage properties. Osteochondral explants (OCEs) from large-animal or human joints present characteristics of native articular cartilage, showing promising potential for application in research on joint diseases. The present review focuses on OCEs and highlights the OCE sources, harvesting techniques, culture systems, applications and future developments. The OCE-centred ex vivo system has the potential to develop into preclinical models mimicking human joint diseases to help elucidate disease mechanisms, prompt therapeutic strategies and facilitate the clinical translation of findings in basic research.

Monolithic InGaN/GaN photonic chips for heart pulse monitoring.

Photo-plethysmography (PPG) making use of a monochromic light source and a photoelectric sensor is a non-invasive detection method to record blood volume changes in vessels and can be used to extract cardiac-related heart pulse information. Here, we demonstrated the fabrication of a monolithic photonic chip by integrating light-emitting diodes (LEDs) with photodetectors (PDs) on the same GaN-on-sapphire wafer containing InGaN/GaN multi-quantum wells (MQWs). The MQWs simultaneously act as light emitters in the LEDs and detectors in the PDs, and their mechanism has been studied. The fabricated chip operating in reflection mode is flip-chip bonded on a flexible polydimethylsiloxane (PDMS) strip, enabling the sapphire surface in close contact with the skin. The optical and electrical properties of the LED and PD have been thoroughly characterized, confirming that the PDs using identical MQWs can detect the reflected light from the LEDs. By attaching the chip to the wrist, PPG heart pulse signals from the arterial blood flow can be obtained, thereby verifying the feasibility of the proposed monolithic chip.

Vertically stacked RGB LEDs with optimized distributed Bragg reflectors.

The design and fabrication of a vertically stacked red-green-blue (RGB) light-emitting diode (LED) with novel, to the best of our knowledge, wavelength-selective distributed Bragg reflectors (DBRs) are demonstrated. The two DBRs are optimized to achieve selective reflectance in the RGB spectral region through theoretical calculations and simulation modeling. The insertion of optimal DBRs into the stack structure can effectively reflect downward emission from the upper chip without filtering the emission from the lower chips, thereby increasing the luminous efficiency for white emission with a color temperature range of 3000-8000 K by 1.6-7.4%. The optical performances of stacked devices with and without DBRs are thoroughly studied, verifying the effectiveness of the proposed wavelength-selective DBR structure.

Packaging of InGaN stripe-shaped light-emitting diodes.

We demonstrate the fabrication of InGaN/GaN stripe-shaped light-emitting diodes (LEDs) in flip-chip packaging (FC-LED) and vertically mounted packaging (VM-LED). Compared to conventionally packaged LEDs, these packaging schemes enhance light output and emission divergence in ways favorable for general lighting applications. The FC-LED can sustain efficiency at high current operations due to effective heat sinking, while the VM-LED excels at light extraction efficiency due to the exposure of two large emission surfaces. Together with the properties of low luminous exitance and emission uniformity, the stripe-shaped LEDs are ideal for the assembly of luminaires. An LED light tube comprising a continuous linear array of 10 stripe-shaped LED chips has been assembled. The optical performance of the light tube is compared to another light tube assembled with conventional square-shaped LED chips (with and without external diffuser) by confocal microscopy. It is found that emission uniformity of the stripe-shaped LED tube is significantly improved, with a threefold increase in illumination area, without efficiency loss associated with diffusers.

Investigation on self-absorption at reduced air pressure in quantitative analysis using laser-induced breakdown spectroscopy.

The self-absorption at reduced air pressure for quantitative analysis of Mn and Cu elements in steel using laser-induced breakdown spectroscopy was investigated. The calibration curves of Mn and Cu elements at the air pressures of 100, 80, 50, 20, and 1 kPa were studied. The results show that, the nonlinearity of calibration curves which caused by self-absorption effects at atmosphere could be significantly improved by reducing the air pressure to 1 kPa, and the coefficients of determination (R2) of linear calibration curves of Mn and Cu lines are all higher than 0.99. The further study explored that the reason for the improvement was that the induced plasma became low density and the self-absorption coefficient was close to 1 when the air pressure reduced to 1 kPa.

Sensitive determinations of Cu, Pb, Cd, and Cr elements in aqueous solutions using chemical replacement combined with surface-enhanced laser-induced breakdown spectroscopy.

In this study, chemical replacement combined with surface-enhanced laser-induced breakdown spectroscopy (CR-SENLIBS) was for the first time applied to improve the detection sensitivities of trace heavy metal elements in aqueous solutions. Utilizing chemical replacement effect, heavy metal ions in aqueous solution were enriched on the magnesium alloy surface as a solid replacement layer through reacting with the high chemical activity metallic magnesium (Mg) within 1 minute. Unitary and mixed solutions with Cu, Pb, Cd, and Cr elements were prepared to construct calibration curves, respectively. The CR-SENLIBS showed a much better detection sensitivity and accuracy for both unitary and mixed solutions. The coefficients of determination R2 of the calibration curves were above 0.96, and the LoDs were of the same order of magnitude, i.e., in the range of 0.016-0.386 µg/mL for the unitary solution, and in the range of 0.025-0.420 µg/mL for the mixed solution. These results show that CR-SENLIBS is a feasible method for improving the detection sensitivity of trace element in liquid sample, which definitely provides a way for wider application of LIBS in water quality monitoring.

Acidity measurement of iron ore powders using laser-induced breakdown spectroscopy with partial least squares regression.

Laser-induced breakdown spectroscopy (LIBS) with partial least squares regression (PLSR) has been applied to measuring the acidity of iron ore, which can be defined by the concentrations of oxides: CaO, MgO, Al2O3, and SiO2. With the conventional internal standard calibration, it is difficult to establish the calibration curves of CaO, MgO, Al2O3, and SiO2 in iron ore due to the serious matrix effects. PLSR is effective to address this problem due to its excellent performance in compensating the matrix effects. In this work, fifty samples were used to construct the PLSR calibration models for the above-mentioned oxides. These calibration models were validated by the 10-fold cross-validation method with the minimum root-mean-square errors (RMSE). Another ten samples were used as a test set. The acidities were calculated according to the estimated concentrations of CaO, MgO, Al2O3, and SiO2 using the PLSR models. The average relative error (ARE) and RMSE of the acidity achieved 3.65% and 0.0048, respectively, for the test samples.

Whispering gallery mode lasing in optically isolated III-nitride nanorings.

III-nitride nanorings fabricated from a combination of hybrid-nanosphere-lithography and laser lift-off processes is demonstrated. Being formed on an interfacial metallic layer optically coupling between the optical ring and its substrate is eliminated, maximizing optical confinement of whispering gallery resonant mode within the ring cavity. The tapered cross-sectional profile also promotes coupling of emitted light into resonant modes. Optically pumped lasing with a dominant peak at 421.5 nm is observed at room temperature, with threshold energy density of ∼6.5 mJ/cm2. Etch-induced sidewall roughness causes scattering of light at the interface to diminish confinement, and is also responsible for the mode-splitting effect according to finite-difference time-domain simulations.

Accuracy improvement on polymer identification using laser-induced breakdown spectroscopy with adjusting spectral weightings.

A new approach to polymer identification by laser-induced breakdown spectroscopy (LIBS) with adjusting spectral weightings (ASW) was developed in this work aiming at improving the identification accuracy. This approach has been achieved through increasing the intensities of specific characteristic spectral lines which are important to polymer identification but difficult to be excited. Using the ASW method, the identification accuracies of all 11 polymers were increased to nearly 100%, while the accuracies of PE, PU, PP and PC were only 98%, 74%, 90% and 98%, respectively, without using the ASW method.

Effect of cervical artificial disc replacement on adjacent inferior intervertebral space stress.

PURPOSE: The aim of this study was to investigate the effects of C5/6 cervical artificial disc replacement (CADR), discectomy and intervertebral fusion on adjacent inferior (C6/7) intervertebral space stress, and provide a basis for application of CADR. METHODS: Eleven fresh-frozen multisegmental (C3-T1) cervical spine specimens from healthy adults were studied. For analysis of stress on the adjacent inferior (C5/6) segment, they were divided into intact group, discectomy group, CADR group and interbody fusion group. The axial load (25-150 N) was exerted on each group. The changes of the adjacent inferior (C6/7) intervertebral space stress were observed. RESULTS: The adjacent inferior intervertebral space stress in the CADR group was near to that of the intact group, without significant difference (p > 0.05). The stress in the discectomy group was significantly higher than in the intact group, and lower than in the interbody fusion group (p < 0.05 and p < 0.01, respectively). The stress in the interbody fusion group was significantly higher than in the intact and CADR groups, respectively (p < 0.01).

Single-mode whispering gallery lasing from metal-clad GaN nanopillars.

An ordered hexagonal closed-packed nanopillar array is fabricated on GaN. A metal coating is then applied to encapsulate the pillars for promoting optical confinement within the cylindrical cavity. Room-temperature lasing at 373 nm is observed under pulsed excitation, at a lasing threshold of 0.42 MW/cm2. With pillar diameters of around 980 nm, the number of modes overlapping the emission spectrum is reduced, giving rise to single-mode whispering gallery stimulated emission. Finite-difference time-domain simulations are carried out for the prediction of resonant frequencies and electric field patterns corresponding to the resonant modes.

The effects of dexmedetomidine administered at various times on acute lung injury in rats.

OBJECTIVE: To investigate the effects of dexmedetomidine (Dex) treatment administered at various times on acute lung injury (ALI). MATERIALS AND METHODS: Thirty Wistar rats were randomly divided into five groups (n = 6/group). Lipopolysaccharide (LPS) was intraperitoneally injected into the rats in the LPS, Dex1, Dex2, and Dex3 groups to induce ALI, while the control group (C) was left untreated. Rats in the Dex1 group were intraperitoneally administered with 50 µg/kg Dex 30 minutes before modeling. Rats in the Dex2 group were injected with 25 µg/kg Dex 30 minutes before modeling and two hours after. Rats in the Dex3 group received 50 µg/kg Dex two hours after modeling. The animals in the C and LPS groups were given an equal volume of saline. The wet-to-dry (W/D) weight ratio of the rats' lungs was calculated, and pathological alterations in lung tissues were observed. The concentrations of inflammation-related factors and the expression of Janus kinase 1 (JAK1), signal transducer and activator of transcription 3 (STAT3), and matrix metallopeptidase 9 (MMP9) were measured. RESULTS: The W/D ratio, expression of inflammatory factors, and expression of JAK1, STAT3, and MMP9 were significantly increased in the ALI rats (p < 0.05) compared with the C group. The level of anti-inflammatory factors in the Dex-treated groups was also significantly increased compared with the LPS group (p < 0.05). The concentration of anti-inflammatory factors in the Dex2 group was significantly higher than that recorded in the Dex1 and Dex3 groups (p < 0.05). CONCLUSIONS: Dex treatment administered at different times protects rats against LPS-induced ALI to varying degrees. The protective effects of Dex were most robust when administered both before and after LPS stimulation.

Osteoporosis, fracture, osteoarthritis & sarcopenia: A systematic review of circulating microRNA association.

Circulating microRNAs (c-miRs) show promise as biomarkers. This systematic review explores their potential association with age-related fracture/osteoporosis (OP), osteoarthritis (OA) and sarcopenia (SP), as well as cross-disease association. Most overlap occurred between OA and OP, suggesting potentially shared microRNA activity. There was little agreement in results across studies. Few reported receiver operating characteristic analysis (ROC) and many identified significant dysregulation in disease, but direction of effect was commonly conflicting. c-miRs with most evidence for consistency in dysregulation included miR-146a, miR-155 and miR-98 for OA (upregulated). Area under the curve (AUC) for miR-146a biomarker performance was AUC 0.92, p = 0.028. miR-125b (AUC 0.76-0.89), miR-100, miR-148a and miR-24 were consistently upregulated in OP. Insufficient evidence exists for c-miRs in SP. Study quality was typically rated intermediate/high risk of bias. Wide study heterogeneity meant meta-analysis was not possible. We provide detailed critique and recommendations for future approaches in c-miR analyses based on this review.

Elevated osteopontin level of synovial fluid and articular cartilage is associated with disease severity in knee osteoarthritis patients.

OBJECTIVE: To investigate osteopontin (OPN) levels in both synovial fluid and articular cartilage of patients with primary knee osteoarthritis (OA) and their relationship with severity of the disease. METHOD: Fifty patients aged 48-81 years with knee OA and 10 healthy controls were enrolled in this study. Anteroposterior knee radiographs or/and Mankin score were taken to determine the disease severity of the affected knee. The radiographic grading of OA in the knee was performed by using the Kellgren-Lawrence criteria. OPN levels in synovial fluid were measured using enzyme-linked immunosorbent assay. OPN levels in articular cartilage were assessed by immunohistochemical methods. RESULTS: Compared to healthy controls, OA patients had higher OPN concentration in synovial fluid (4519.60+/-1830.37, 95%CI 3999.42-5039.79 vs 1179.70+/-303.39, 95%CI 1035.53-1438.74 pg/ml, P<0.001)and articular cartilage(0.6+/-0.06, 95%CI 0.59-0.62 vs 0.43+/-0.07, 95%CI 0.38-0.48, P<0.01). In addition, synovial fluid OPN levels showed a positive correlation with articular cartilage OPN levels (r=0.411, 95%CI 0.150-0.619, P=0.003). Subsequent analysis showed that synovial fluid OPN levels significantly correlated with severity of disease (Spearman's rho=0.581, 95%CI 0.335-0.726, P<0.001). Furthermore, the articular cartilage levels of OPN also correlated with disease severity (Spearman's rho=0.675, 95%CI 0.500-0.808, P<0.001). CONCLUSIONS: OPN in synovial fluid and articular cartilage is associated with progressive joint damage and is likely to be a useful biomarker for determining disease severity and progression in knee OA.

Acute Cellular Rejection and Infection Rates in Alemtuzumab vs Traditional Induction Therapy Agents for Lung and Heart Transplantation: A Systematic Review and Meta-analysis.

BACKGROUND AND OBJECTIVES: Heart and lung transplantation is a high-risk procedure requiring intensive immunosuppressive therapy for preventing organ rejection. Alemtuzumab, a CD52-specific monoclonal antibody, is increasingly used for induction therapy compared with conventional agents. However, there has been no systematic review comparing its efficacy with traditional therapeutic drugs. METHODS: PubMed and EMBASE were searched to October 1, 2017, for articles on alemtuzumab in cardiothoracic transplant surgery. Of the 433 studies retrieved, 8 were included in the final meta-analysis. RESULTS: In lung transplantation, alemtuzumab use was associated with lower odds of acute cellular rejection compared with antithymocyte globulin (odds ratio [OR], 0.21; 95% CI, 0.11-0.40; P < .001), lower acute rejection rates (OR, 0.12; 95% CI, 0.03-0.55; P < .01), and infection rates (OR, 0.69; 95% CI, 0.35-1.36; P = .33) when compared with basiliximab. Multivariate meta-regression analysis found that mean age, male sex, single lung transplant, double lung transplant, cytomegalovirus or Epstein-Barr virus status, idiopathic pulmonary fibrosis, cystic fibrosis, and mean ischemic time did not significantly influence acute rejection outcomes. For heart transplantation, alemtuzumab use was associated with lower acute rejection rates when compared with tacrolimus (OR, 0.44; 95% CI, 0.30-0.66; P < .001). CONCLUSIONS: Alemtuzumab use was associated with lower rejection rates when compared with conventional induction therapy agents (antithymocyte globulin, basiliximab, and tacrolimus) in heart and lung transplantation. However, this was based on observational studies. Randomized controlled trials are needed to verify its clinical use.

WITHDRAWN: Acute Cellular Rejection and Infection Rates in Alemtuzumab vs Traditional Induction Therapy Agents for Lung and Heart Transplantation: A Systematic Review and Meta-analysis.

The Publisher regrets that this article is an accidental duplication of an article that has already been published in Transplant Proc. 2018; 50 (10):3739-3747, https://doi.org/10.1016/j.transproceed.2018.08.018. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.

[Outcomes of pregnancy among women with alpha-thalassemia minor: A retrospective study of Pingguo county in Guangxi Zhuang Autonomous Region].

Objective: To investigate the association between the value of α-thalassemia minor and the outcomes in pregnant women. Methods: A total of 445 pregnant women with α-thalassemia minor were selected as thalassemia group in the Pingguo County Maternal and Child Health Hospital of Guangxi from January 2011 to December 2015, with ratio of 1∶4 healthy pregnant women was randomly recruited as non-thalassemia group. Clinical characteristics and pregnancy outcomes of the two groups were retrospectively analyzed using methods including t test, χ(2) test, and logistic regression model and ROC curve. Results: There were no significant differences noticed in factors as age, BMI, gestational age and educational level of the two groups. Hemoglobin of the thalassemia group was significantly lower than that of the non-thalassemia group (P<0.001). Differences on parity, ethnicities or occupation were statistically significant. Results from univariate analysis showed that the proportions of low birth weight, small for date infant and 1 min Apgar score<7 were higher in the thalassemia group, but the ratio of adverse pregnancy outcomes was comparable on parameters as preterm birth, stillbirth, macrosomia. Findings from the unconditional logistic regression showed that pregnancy complicated with α-thalassemia minor appeared a risk for both newborns with low birth weight (aOR=2.29, 95%CI: 1.32-3.95) and small for date infant (aOR= 2.11, 95%CI: 1.16-3.84). The ROC curve showed that α-thalassemia minor combined with multiple indicators presented a certain predictive value on neonatal birth weight. Conclusion: Pregnancy complicated with α-thalassemia minor was likely to increase the risk of birth weight loss in newborns, suggesting that prenatal care for pregnant women with thalassemia be strengthened, in order to reduce the incidence of adverse pregnancy outcomes.

Flexible Free-Standing III-Nitride Thin Films for Emitters and Displays.

The majority of a GaN light-emitting diode (LED) is released from its sapphire substrate through selective-area laser lift-off to form a freely suspended light emitter. By virtue of being suspended in air without supporting substrates, the ultrathin crystalline and crack-free film possesses flexibility and bendability. The free-standing LEDs benefit from significant relaxation of strain, evident from red-shifting of the E2(high) phonon frequencies as measured by Raman spectroscopy toward those of strain-free free-standing GaN substrates. The phonon frequencies remain invariant upon bending of the film; this indicates that the properties of the flexible device will not be dependent on the bending curvatures. The observation of pronounced spectral blue-shifts from the photoluminescence (PL) spectrum from the flexible regions further confirms the occurrence of strain relaxation in the quantum wells. Being free-standing and thus lacking a direct heat-sinking pathway, emissions from the different regions of the suspended film can be affected by thermal effects to different extents, which are investigated by long-wave infrared thermometry. Heat accumulation is determined to be most severe at the far end of the flexible stripe at higher currents, leading to reduced efficiencies and electroluminescence (EL) spectral red-shifts. Based on this architecture, a monolithic 3 × 4 dot-matrix microdisplay prototype is demonstrated, comprising three adjacent flexible stripe emitters with four individually addressable pixels on each stripe. This proof-of-concept demonstration opens up new opportunities for GaN optoelectronics for a wide range of flexible display and visual applications.

Ultralow-threshold electrically injected AlGaN nanowire ultraviolet lasers on Si operating at low temperature.

Ultraviolet laser radiation has been adopted in a wide range of applications as diverse as water purification, flexible displays, data storage, sterilization, diagnosis and bioagent detection. Success in developing semiconductor-based, compact ultraviolet laser sources, however, has been extremely limited. Here, we report that defect-free disordered AlGaN core-shell nanowire arrays, formed directly on a Si substrate, can be used to achieve highly stable, electrically pumped lasers across the entire ultraviolet AII (UV-AII) band (∼320-340 nm) at low temperatures. The laser threshold is in the range of tens of amps per centimetre squared, which is nearly three orders of magnitude lower than those of previously reported quantum-well lasers. This work also reports the first demonstration of electrically injected AlGaN-based ultraviolet lasers monolithically grown on a Si substrate, and offers a new avenue for achieving semiconductor lasers in the ultraviolet B (UV-B) (280-320 nm) and ultraviolet C (UV-C) (<280 nm) bands.

Bullous pemphigoid antigen: cDNA cloning, cellular expression, and evidence for polymorphism of the human gene.

A human epidermal keratinocyte lambda gt11 recombinant cDNA library was screened with a 0.45-kb cDNA that was generated by polymerase chain reaction (PCR) amplification of a segment of human bullous pemphigoid (BP) antigen mRNA. The screen yielded five clones, the largest one, pcBPA-4, being 2.3 kb in size. The pcBPA-4 cDNA hybridized in Northern analyses with an approximately 9-kb mRNA from cultured keratinocytes, whereas no hybridization signal was detected with RNA from human skin fibroblast, fibrosarcoma HT-1080 cells, or amniotic epithelial WISH cell cultures. Nucleotide sequencing of pcBPA-4 revealed an open reading frame encoding a putative polypeptide of 447 amino acids. This polypeptide showed 88% homology with corresponding mouse BP antigen sequences, and a region of it was identical to a segment in previously published human BP antigen sequences. The 2.3-kb cDNA isolated here was different from a previously published human BP antigen cDNA, in that the open reading frame coded for 264 additional amino acids at the carboxyl end of the putative polypeptide. Known human BP antigen amino acid sequences, compared with mouse sequences, were predicted to be moderately divergent with a unit of evolutionary period (UEP) of 4.5 millions of years (MY). Southern hybridizations suggested that the BP antigen gene (BPAG1) is present as a single copy in the human genome. Southern analyses also revealed the presence of a StuI restriction fragment length polymorphism that can be used for linkage analyses to study the inheritance of a particular BPAG1 allele and a heritable cutaneous disorder affecting the basement membrane zone, such as epidermolysis bullosa.