Curcumin in the treatment of oral submucous fibrosis: a systematic review and meta-analysis of randomized controlled trials

The objective was to evaluate the efficacy of curcumin in improving mouth opening (MO), burning sensation (BS), and tongue protrusion (TP) symptoms in patients with oral submucous fibrosis (OSF). An electronic search up to November 2022 was conducted in the PubMed, Web of Science, Embase, EBSCO, ProQuest, and Cochrane Library databases to identify studies using curcumin in the treatment of OSF with comparison to control groups (drugs previously proven to be effective for OSF treatment) or placebo. Only randomized controlled trials (RCTs) were considered. RevMan 5.3 software was used for the meta-analysis. Thirteen RCTs met the eligibility criteria and were included in the analysis. The results showed no significant improvement in MO (in millimetres) for curcumin when compared to control at 1 month (P = 0.91), 2 months (P = 0.54), 3 months (P = 0.56), or 6 months (P = 0.17) of treatment. There was no significant difference in BS (assessed using a visual analogue scale) between curcumin and control after 1 month (P = 0.05), 2 months (P = 0.64), 3 months (P = 0.13), or 6 months (P = 0.56) of treatment. Compared with the control groups, treatment with curcumin for 1 month (P = 0.32), 2 months (P = 0.07), and 3 months (P = 0.14) did not significantly improve the TP (in millimetres) of patients. The administration of curcumin, whether topically applied or taken orally, did not confer statistically significant improvements in MO, BS, or TP in comparison to the control treatments, among patients with OSF. The results of this meta-analysis showed that compared to placebo, the application of curcumin for 6 months markedly alleviated BS (P < 0.001). Curcumin treatment in OSF reaches a clinically effective range, but more bioavailability-centred outcomes should be reported. Robust multicentre RCTs are warranted to elucidate the efficacy of curcumin in improving specific outcomes like MO, BS, and TP in patients with this condition. Defining the therapeutic role of this natural compound may provide an effective botanical alternative for managing OSF.

Sophora tonkinensis: response and adaptation of physiological characteristics, functional traits, and secondary metabolites to drought stress

The medicinal plant Sophora tonkinensis is a characteristic Chinese shrub of karst areas. The arid climate in karst areas produces high-quality S. tonkinensis; however, the mechanisms of drought tolerance are not clear, which restricts sustainable plantings of S. tonkinensis. This study involved a 20-day drought stress experiment with potted S. tonkinensis and threee soil water regimes: control (CK), mild drought (MDT), and severe drought (SDT). Plant morphology, biomass, physiological indicators, alkaloid content, and other changes under drought stress were monitored. The content of soluble sugars and proteins, and activity of antioxidant enzymes in leaves and roots were higher under drought than CK, indicating that S. tonkinensis is tolerant to osmotic stress in early drought stages. Content of matrine and oxymatrine increased gradually with increasing drought duration in the short term. The epidermis of S. tonkinensis leaves have characteristics of desert plants, including upper epidermal waxy layer, lower epidermal villi, and relatively sunken stomata, suggesting that S. tonkinensis has strong drought tolerance. In conclusion, drought stress changed the cell structure of S. tonkinensis, induced antioxidant enzyme activity and increased its resistance to drought.

Willingness to receive and recommend hypothetical mpox vaccination and associated factors in Chinese adults: a community-based survey in Shenzhen, China

OBJECTIVES

China may face new threats to public health due to the increased risk of imported mpox (monkeypox) cases. However, research gaps exist in the acceptance of mpox vaccination and potential associated factors in the Chinese population.

STUDY DESIGN

We conducted a cross-sectional study targeting community residents in Shenzhen, China, from August 5 to September 7 2022.

METHODS

A self-administered questionnaire was used to collect information about demographic and health characteristics, mpox-related perceptions, and attitudes towards mpox vaccination. Multivariable logistic regression models were applied to detect the factors associated with willingness to receive and recommend mpox vaccination.

RESULTS

A total of 2293 community residents were included in the analyses (average age: 34.03, female: 72.6%). Among the participants, 76.9% were aware of mpox, 62.1% were aware of the global mpox outbreak, but only 53.6% had a high knowledge level of mpox. Males had a higher proportion of high knowledge (56.9% vs 52.3%, P＜0.05) and a lower proportion of high worry (30.2% vs 45.4%, P＜0.05) than females. Approximately 69.1% of the participants were willing to vaccinate against mpox, and 69.6% were willing to recommend mpox vaccination to people around them, in which no gender difference was found. The obstacle reported most among people hesitant to receive vaccination was concerning the safety and side-effects, whereas it changed to be concerning the suitability due to individual health differences among people hesitant to recommend mpox vaccines. Factors associated with the willingness to receive and recommend mpox vaccination included having a history of influenza vaccination, having a history of COVID-19 vaccination, being aware of the global mpox outbreak, having a high knowledge level of mpox, and having a high level of mpox-related worry.

CONCLUSIONS

This study identified a moderate willingness to receive and recommend mpox vaccination among Chinese adults. Without gender differences, willingness to receive and recommend mpox vaccination was significantly associated with mpox-related perceptions, such as awareness, knowledge, and worry. Authoritative and up-to-date information is needed to help the general population improve public confidence in mpox vaccines in China.

Distinguishing preeclampsia using the falling scaled slope (FSS) --- a novel photoplethysmographic morphological parameter

BACKGROUND

Preeclampsia (PE) presence could lead to hemodynamic changes. Previous research suggested that morphological parameters based on photoplethysmographic pulse waves (PPGW) could help diagnose PE.

AIM

To investigate the performance of a novel PPGPW-based parameter, falling scaled slope (FSS), in distinguishing PE. To investigate the advantages of the machine learning algorithm over the conventional statistical methods in the analysis.

METHODS

Eighty-one pieces of PPGPW data were acquired for the study (PE, n = 44; normotensive, n = 37). The FSS values were calculated and used to construct a PE classifier using the K-nearest neighbors (KNN) algorithm. A predicted PE state varying from 0 to 1 was also calculated. The classifier's performance in distinguishing PE was evaluated using the ROC and AUC. A comparison was conducted with previously published PPGPW-based models.

RESULT

Compared to the previous PPGPW-based parameters, FSS showed a better performance in distinguishing PE with an AUC value of 0.924, the best threshold of 0.498 could predict PE with a sensitivity of 84.1% and a specificity of 89.2%. As for the analysis method, training a classifier using the KNN algorithm had an advantage over the conventional statistical methods with the AUC values of 0.878 and 0.749, respectively.

CONCLUSION

The result indicated that FSS might be an effective tool for identifying PE. Moreover, the machine learning algorithm could further help the data analysis and improve performance. [Figure: see text].

Radiation-Induced Nasopharyngeal Necrosis in Locally-Recurrent Nasopharyngeal Carcinoma Patients after Re-Radiotherapy

PURPOSE/OBJECTIVE(S)

Re-radiotherapy (re-RT) is the main treatment for locally recurrent nasopharyngeal carcinoma (lrNPC) patients, and commonly led to radiation-induced nasopharyngeal (NP) necrosis, which was lethal but rare study has focused on it. The aim of this study was to evaluate the cause and impact of radiation-induced NP necrosis in lrNPC patients who received re-RT.

MATERIALS/METHODS

Totally 252 lrNPC patients who received re-RT between January 2013 and December 2020 were retrospectively collected. The inclusion criteria were as follows: (1) no NP necrosis before re-RT; (2) complete medical records, including treatment, clinical and dosimetric information; (3) conventional fractionated radiotherapy. All patients received intensity-modulated radiotherapy ± chemotherapy. Radiation-induced NP necrosis was diagnosed by magnetic resonance imaging and/or electronic nasopharyngoscopy. Dosimetric factors of the planning target volume of primary tumor (PTVp) were extracted from the dose-volume histogram (DVH), which was rescaled to an equivalent dose of 2 Gy per fraction (EQD 2 Gy) using a linear quadratic model. Logistic regression was used to identify the independent prognostic factors for generating the nomogram.

RESULTS

With a median follow-up of 44.63 months (inter-quartile range [IQR], 27.70 - 69.20 months), 47.6% of patients (120/252) occurred radiation-induced NP necrosis, which mostly happened within 1 year post re-RT (median [IQR], 5.83 [3.37 - 11.57] months). The 3-year overall survival was 83.0% vs 39.7% (P<0.001) in lrNPC patients with or without radiation-induced NP necrosis. Except for the fractionated dose, other dosimetric factors of PTVp were not significantly different between two groups, including D98 (dose to 98% of PTVp), D50, D2 and homogeneity index (Table 1). Furthermore, multivariate analysis showed that continuous variable age (HR [95% CI]: 1.04 [1.02 - 1.07], P = 0.003) and tumor volume (HR [95% CI]: 1.02 [1.01 - 1.03], P<0.001), and fractionated dose > 2.22 Gy (HR [95% CI]: 2.36 [1.32 - 4.21], P = 0.004) were independent factors in predicting radiation-induced NP necrosis, which yielded a C-index of 0.742 (95% CI, 0.682 - 0.803) for OS in the nomogram.

CONCLUSION

The incidence of radiation-induced NP necrosis was high in lrNPC patients who received re-RT. Patients with older age, larger tumor volume or receiving fractionated dose over 2.22 Gy were more easily to suffer NP necrosis, which need to explore novel treatment strategies to improve patients' survivals.

DWI-Based Radiomics Predicts the Functional Outcome of Endovascular Treatment in Acute Basilar Artery Occlusion

BACKGROUND AND PURPOSE

Endovascular treatment is a reference treatment for acute basilar artery occlusion (ABAO). However, no established and specific methods are available for the preoperative screening of patients with ABAO suitable for endovascular treatment. This study explores the potential value of DWI-based radiomics in predicting the functional outcomes of endovascular treatment in ABAO.

MATERIALS AND METHODS

Patients with ABAO treated with endovascular treatment from the BASILAR registry (91 patients in the training cohort) and the hospitals in the Northwest of China (31 patients for the external testing cohort) were included in this study. The Mann-Whitney U test, random forests algorithm, and least absolute shrinkage and selection operator were used to reduce the feature dimension. A machine learning model was developed on the basis of the training cohort to predict the prognosis of endovascular treatment. The performance of the model was evaluated on the independent external testing cohort.

RESULTS

A subset of radiomics features (n = 6) was used to predict the functional outcomes in patients with ABAO. The areas under the receiver operating characteristic curve of the radiomics model were 0.870 and 0.781 in the training cohort and testing cohort, respectively. The accuracy of the radiomics model was 77.4%, with a sensitivity of 78.9%, specificity of 75%, positive predictive value of 83.3%, and negative predictive value of 69.2% in the testing cohort.

CONCLUSIONS

DWI-based radiomics can predict the prognosis of endovascular treatment in patients with ABAO, hence allowing a potentially better selection of patients who are most likely to benefit from this treatment.

IL-37 alleviates intervertebral disc degeneration via the IL-1R8/NF-κB pathway

OBJECTIVE

Intervertebral disc degeneration (IDD) has been reported to be a major cause of low back pain (LBP). Interleukin (IL)-37 is an anti-inflammatory cytokine of the interleukin-1 family, which exerts salutary physiological effects. In this study, we assessed the protective effect of IL-37 on IDD progression and its underlying mechanisms.

METHODS

Immunofluorescence (IF) was conducted to measure IL-37 expression in nucleus pulposus tissues. CCK-8 assay and Edu staining were used to examine the vitality of IL-37-treated nucleus pulposus cells (NPCs). Western blot, qPCR, ELISA as well as immunohistochemistry were used to assess senescence associated secreted phenotype (SASP) factors expression; and NF-κB pathway was evaluated by western blot and IF; while IL-1R8 knock-down by siRNAs was performed to ascertain its significance in the senescence phenotype modulated by IL-37. The therapeutic effect of IL-37 on IDD were evaluated in puncture-induced rat model using X-ray, Hematoxylin-Eosin, Safranin O-Fast Green (SO), and alcian blue staining.

RESULTS

We found IL-37 expression decreased in the IDD process. In vitro, IL-37 suppressed SASP factors level and senescence phenotype in IL-1β treated NPCs. In vivo, IL-37 alleviated the IDD progression in the puncture-induced rat model. Mechanistic studies demonstrated that IL-37 inhibited IDD progression by downregulating NF-κB pathway activation in NPCs by activating IL-1R8.

CONCLUSION

The present study suggests that IL-37 delays the IDD development through the IL-1R8/NF-κB pathway, which suggests IL-37 as a promising novel target for IDD therapy.

Self-regulated immobilization behavior of multiple heavy metals via zeolitization towards a novel hydrothermal technology for soil remediation

More efficient soil remediation technologies are highly anticipated to treat large quantities of heavy metal-polluted urban sites nowadays. Herein, a novel hydrothermal technology of converting heavy metal-polluted soils into zeolites for in-situ immobilizing heavy metals was proposed. The zeolites (analcime and cancrinite) could be synthesized hydrothermally with certain Na/Si and Al/Si ratios. The formed zeolites could manage to change their species and structure during zeolitization to accommodate different heavy metals in soil according to their size and charge. Since smaller-size Cu²⁺ was introduced, analcime and some cancrinite possessing small cages could be formed adaptively to immobilize the Cu²⁺ by replacing Na⁺ and forming Cu²⁺-OH and Cu²⁺-O. Whereas, cancrinite with large channels managed to form to immobilize the larger-size Cd²⁺ by forming Cd²⁺-O. Interplanar spacing variation of zeolites also corresponded to their structural change for accommodating different heavy metals. Leaching results showed the amounts of Cu and Cd leached from the synthesized zeolites were reduced to 0.005% and 0.05% respectively, reflecting a more stable immobilization of smaller heavy metals by small cages, in agreement with the results of distribution coefficient (K_d). Negligible effect of pH environment on the leaching rates further confirmed the stable structural immobilization of heavy metals by zeolites.

Carbapenem-resistant Enterobacterales colonization and subsequent infection in a neonatal intensive care unit in Shanghai, China

Background

Colonization has been reported to play an important role in carbapenem-resistant Enterobacterales (CRE) infection; however, the extent to which carriers develop clinical CRE infection and related risk factors in neonatal intensive care unit (NICU) patients is unclear.

Aim

To investigate the frequency of CRE colonization and its contribution to infections in NICU patients.

Methods

CRE colonization screening and CRE infection surveillance were performed in the NICU in 2017 and 2018.

Findings

Among 1230 unique NICU patients who were screened for CRE colonization, 144 patients tested positive (11.7%, 144/1230), with 9.2% (110/1197) in the intestinal tract, which was higher than that in the upper respiratory tract (6.6%, 62/945) (P=0.026). Gestational age, low birth weight and prolonged hospitalization were risk factors for CRE colonization (all P<0.001). Diversilab homology monitoring found an overall 17.4% (25/144) risk of infection among patients colonized with CRE. For carbapenem-resistant Klebsiella pneumoniae (CR-KP) and carbapenem-resistant Escherichia coli (CR-ECO), the risks were 19.1% (21/110) and 13.8% (4/29), respectively. The independent risk factors for CR-KP clinical infection among CR-KP carriers were receiving mechanical ventilation (odds ratio (OR), 10.177; 95% confidence interval (CI), 2.667–38.830; P=0.013), a high level of neonatal nutritional risk assessment (OR, 0.251; 95% CI, 0.072–0.881; P=0.031) and a high neonatal acute physiology II (SNAP-II) score (OR, 0.256; 95% CI, 0.882–1.034; P=0.025).

Conclusions

The colonization of CRE may increase the incidence of corresponding CRE infection in NICU patients. Receiving mechanical ventilation, malnutrition and critical conditions with high SNAP-II scores were independent risk factors for subsequent CR-KP clinical infection.

Clinical benefits of TNF-α inhibitors in Chinese adult patients with NLRP3-associated autoinflammatory disease

BACKGROUND

Nucleotide-binding oligomerization domain-like receptor family, pyrin domain containing 3 (NLRP3)-associated autoinflammatory disease (NLRP3-AID) is a rare, heterogeneous disease entity associated with mutations in NLRP3. Biologic therapy for NLRP3-AID yields diverse results.

OBJECTIVES

We aimed to evaluate the clinical features and outcomes of Chinese adult patients with NLRP3-AID who were treated with tumour necrosis factor (TNF)-α inhibitors.

METHODS

Five patients with NLRP3-AID were diagnosed and treated with TNF-α inhibitors at Peking Union Medical College Hospital between 2017 and 2020 and were followed up for 6 to 12 months. All patients were systematically studied for treatment outcomes, including clinical manifestations and inflammatory markers.

RESULTS

All five adult NLRP3-AID patients were Chinese Han, and four patients were males. The mean age at disease onset was 4.2 ± 4.1 years, and the mean time of diagnosis delay was 19.8 ± 6 years. All patients received TNF-α inhibitors with or without methotrexate/prednisone. During follow-up, all patients achieved remarkable clinical remission of skin lesions and polyarthritis and showed improvements in acute-phase reactants, inflammatory cytokines, patient visual analogue scale, physician global assessment and 36-item Short Form (SF-36).

CONCLUSIONS

Early diagnosis and effective therapy for NLRP3-AID are essential for avoiding irreversible organ damage. TNF-α inhibitors might serve as a therapeutic alternative for patients with NLRP3-AID who have unsatisfactory responses or no access to interleukin-1 inhibitors.

Application of fracture body surface localization film combined with CT volume rendering in the minimally invasive rib fractures internal fixation

OBJECTIVE

To investigate the application value of the technique of fracture body surface localization film combined with CT volume rendering in the selection of minimally invasive incision for internal fixation of rib fractures.

PATIENTS AND METHODS

Clinical data of 55 cases of patients who underwent internal fixation for rib fracture in our hospital from June 2019 to April 2020 were selected. The differences in the accuracy of preset incision, incision length, operation time, intraoperative blood loss, postoperative wound drainage, and postoperative pain score between the group with fracture body surface localization film combined with CT volume rendering (n=32) and the group with traditional localization method (n=23).

RESULTS

Compared with traditional localization method, fracture body surface localization film combined with CT volume rendering could improve the accuracy of surgical incision, reduce the operation time, incision length, intraoperative blood loss, postoperative wound drainage, and postoperative pain score (p<0.05).

CONCLUSIONS

The application of fracture body surface localization film combined with CT volume rendering has obvious effects on the accurate selection of incision of rib fracture internal fixation, and it is an effective method that is worthy of promotion.

[Study on the effect of integrated traditional Chinese and western medicine in the treatment of brucellosis]

Objective: To observe the clinical effect of integrated traditional Chinese and western medicine on brucellosis and its influence on humoral immune indexes. Methods: In October 2019, 169 cases of brucellosis hospitalized in Tianjin Second People's Hospital were selected as the research objects, and divided into two groups according to the random number method, 84 cases in the integrated treatment group and 85 cases in the western medicine treatment group. The western medicine treatment group was given antibiotics and other routine western medicine support treatment. The integrated treatment group was given traditional Chinese medicine for treatment based on syndrome differentiation, on the basis of western medicine treatment group, and 6 weeks was a course of treatment. The clinical efficacy and Traditional Chinese Medicine (TCM) syndrome scores were compared between the two groups of patients after treatment, and the changes in humoral immune indexes, biochemical, and liver and kidney functions of the patients before and after treatment were analyzed. Results: The total effective rate was 100.00% (84/84) in the integrated treatment group and 97.65% (83/85) in the western medicine treatment group. The difference was not statistically significant (P>0.05) . The difference was not statistically significant (P>0.05) . There was no statistically significant difference in TCM syndrome scores between the two groups before treatment (P>0.05) , and the TCM syndrome scores after treatment were lower than before treatment (P<0.05) . Among them, the TCM syndrome scores of the integrated treatment group were lower than those of the western medicine treatment group (P<0.05) . There was no significant difference in IgG, IgA, IgM, C3, C4, miRNA-155, C-reactive protein (CRP) , erythrocyte sedimention rate (ESR) , alanine aminotransferase (ALT) and aspartate aminotransferase (AST) between the two groups before treatment (P>0.05) . After treatment, IgG, IgA, IgM, miRNA-155, CRP, ESR, ALT and AST were all lower than before treatment, and C3 and C4 complement levels were higher than before treatment (P<0.05) . Among them, IgG, IgA, IgM, miRNA-155, CRP, ESR, ALT and AST in the integrative treatment group were all lower than the western medicine treatment group, while the C3 and C4 complement levels were higher than the western medicine treatment group (P<0.05) . Conclusion: The treatment of brucellosis with integrated traditional Chinese and western medicine can significantly improve the TCM syndrome score and reduce the levels of CRP and ESR. The mechanism of action may be related to the regulation of the patient's humoral immunological indicators.

Comparison of Three Normalization Methods in Monitoring Analgesic Depth with Photoplethysmographic Diastolic Interval

The purpose of the present study was to investigate the ability of three different normalization methods, namely root mean square (RMS) value, mean value, and maximum which referred to pulse beat interval (PBI), based on photoplethysmographic diastolic interval (DI) in response to laryngeal mask airway (LMA) insertion under various remifentanil concentrations during general anesthesia. Sixty patients were randomly allocated to one of the four groups to receive a possible remifentanil effect-compartment target concentration (Ce_remi) of 0, 1, 3, or 5 ng/ml, and an effect-compartment target controlled infusion of propofol to maintain the state entropy (SE) at 40~60. Three normalized measures DI_RMS, DI_Mean, and DIPBI were compared with the DI values without normalization. Before LMA insertion, only DI showed a considerable correlation with remifentanil concentrations. DI_RMS and DI_Mean performed better than DI in discriminating 'insufficient' concentrations (0 and 1 ng/ml) from 'sufficient' concentrations (3 and 5 ng/ml). DIRMS was superior to all other variables in grading analgesic depth after nociceptive event occurred with PK value of 0.836. These results demonstrate that the normalization using RMS value, compared to using mean value and maximum, seems to provide a more effective approach for signal pre-processing.

Intrinsic Mechanism for Anisotropic Magnetoresistance and Experimental Confirmation in Co_{x}Fe_{1-x} Single-Crystal Films

Using first-principles transport calculations, we predict that the anisotropic magnetoresistance (AMR) of single-crystal Co_{x}Fe_{1-x} alloys is strongly dependent on the current orientation and alloy concentration. An intrinsic mechanism for AMR is found to arise from the band crossing due to magnetization-dependent symmetry protection. These special k points can be shifted towards or away from the Fermi energy by varying the alloy composition and hence the exchange splitting, thus allowing AMR tunability. The prediction is confirmed by delicate transport measurements, which further reveal a reciprocal relationship of the longitudinal and transverse resistivities along different crystal axes.

Effect of Laryngeal Mask Airway Insertion on Parameters Derived From Catacrotic Phase of Photoplethysmography Under Different Concentrations of Remifentanil

BACKGROUND

Some parameters have been extracted from photoplethysmography (PPG) with a good relativity with nociception, but without encouraging results in qualifying the balance of nociception-anti-nociception (NAN). The features of PPG have not been thoroughly depicted and more prospective univariate parameters deserve to be explored. The aim of this study was to investigate the ability of parameters derived from catacrotic phase of PPG to grade the level of analgesia.

METHODS

45 patients with ASA I or II were randomized to receive a remifentanil effect-compartment target controlled infusion (Ceremi) of 0, 1, or 3 ng/ml, and a propofol effect-compartment target controlled infusion to maintain an acceptable level of hypnosis with state entropy (SE) at 40~60. Laryngeal mask airway (LMA) insertion was applied as a noxious stimulus. Five diastole-related parameters, namely diastolic interval (DI), diastolic slope (DS), the minimum slope during catacrotic phase (DSmin), the interval between DSmin and its nearest trough (DTI), and area difference ratio (ADR), were extracted. Pulse beat interval (PBI) was calculated as a reference parameter.

RESULTS

LMA insertion elicited a significant variation in all parameters except ADR during Ceremi of 0 and 1 ng/ml. Compared to PBI (prediction probability ([Formula: see text]) = 0.796), the parameters of DI, DS, and DTI presented a better consistence with the level of anti-nociceptive medication, with [Formula: see text] of 0.825, 0.822, and 0.822 respectively.

CONCLUSION

The features extracted from catacrotic phase of PPG, including DI, DS, and DTI, could provide a promising potential to qualify the balance of NAN.

MiR-21 inhibitor improves locomotor function recovery by inhibiting IL-6R/JAK-STAT pathway-mediated inflammation after spinal cord injury in model of rat

OBJECTIVE

To investigate the function of miRNA-21 and interleukin-6 receptor/Janus Kinase-Signal transducer and activator of transcription (IL-6R/JAK-STAT) pathway in microglia on inflammatory responses after spinal cord injury (SCI).

MATERIALS AND METHODS

This study first detected respectively the protein level of inflammatory factor inducible nitric oxide synthase (iNOS) and tumor necrosis factor alpha (TNF-α) by Western blotting after transfection of miR-21 or administration of miR-21 inhibitor in activated microglia cells of rat in vitro. The quantitative Real-time polymerase chain reaction (qRT-PCR) was utilized to detect the expression of IL-6R under two different interventions. Next, we established a model of spinal cord injury in rat and inspected miR-21 and IL-6R in SCI rat by qRT-PCR. In addition, the protein levels of iNOS and TNF-α in SCI rat were detected by Western blotting. MiR-21 inhibitor was injected into the injured area of SCI rat to delve into the function of miR-21 down-expression on iNOS and TNF-α expression by Western blot as well as the RNA levels of IL-6R, JAK and STAT3 by qRT-PCR. Furthermore, the SCI rat with movement and coordination of hindlimbs was observed by Basso-Beattie-Bresnahan locomotor rating scale (BBB scale) after miR-21 down-expression.

RESULTS

Compared with the microglia transfected with miR-21, the execution of inhibitor in microglia effectively relieved the expression of IL-6R and the breakout of iNOS and TNF-α. Meanwhile, the increase of miR-21 was significantly observed in SCI rat along with significant improvement of inflammatory response-related factors including iNOS and TNF-α. After that, we injected SCI rat with miR-21 inhibitor into the spinal cord injury area and found the inhibition of miR-21 decreased the protein levels of iNOS and TNF-α. Simultaneously, down-expression of miR-21 evidently declined the RNA levels of IL-6R, JAK, and STAT3 in SCI rat. Compared with the sham-operated rat, the movement and coordination of hindlimbs of the SCI group displayed dramatic dysfunction. However, miR-21 down-expression elevated the movement and coordination of hindlimbs of the SCI rat than those of the only injury group.

CONCLUSIONS

Inhibition of miR-21 can promote the recovery of spinal cord injury by down-regulating IL-6R/JAK-STAT signaling pathway and inhibiting inflammation.

[Emotion Recognition Based on Multiple Physiological Signals]

Emotion is a series of reactions triggered by a specific object or situation that affects a person's physiological state and can, therefore, be identified by physiological signals. This paper proposes an emotion recognition model. Extracted the features of physiological signals such as photoplethysmography, galvanic skin response, respiration amplitude, and skin temperature. The SVM-RFE-CBR(Recursive Feature Elimination-Correlation Bias Reduction-Support Vector Machine) algorithm was performed to select features and support vector machines for classification. Finally, the model was implemented on the DEAP dataset for an emotion recognition experiment. In the rating scale of valence, arousal, and dominance, the accuracy rates of 73.5%, 81.3%, and 76.1% were obtained respectively. The result shows that emotional recognition can be effectively performed by combining a variety of physiological signals.

Photoplethysmography-derived approximate entropy and sample entropy as measures of analgesia depth during propofol-remifentanil anesthesia

The ability to monitor the physiological effect of the analgesic agent is of interest in clinical practice. Nonstationary changes would appear in photoplethysmography (PPG) during the analgesics-driven transition to analgesia. The present work studied the properties of nonlinear methods including approximate entropy (ApEn) and sample entropy (SampEn) derived from PPG responding to a nociceptive stimulus under various opioid concentrations. Forty patients with ASA I or II were randomized to receive one of the four possible remifentanil effect-compartment target concentrations (Ce_remi) of 0, 1, 3, and 5 ng·ml^-1 and a propofol effect-compartment target-controlled infusion to maintain the state entropy (SE) at 50 ± 10. Laryngeal mask airway (LMA) insertion was applied as a standard noxious stimulation. To optimize the performance of ApEn and SampEn, different coefficients were carefully evaluated. The monotonicity of ApEn and SampEn changing from low Ce_remi to high Ce_remi was assessed with prediction probabilities (P_K). The result showed that low Ce_remi (0 and 1 ng·ml^-1) could be differentiated from high Ce_remi (3 and 5 ng·ml^-1) by ApEn and SampEn. Depending on the coefficient employed in algorithm: ApEn with k = 0.15 yielded the largest P_K value (0.875) whereas SampEn gained its largest P_K of 0.867 with k = 0.2. Thus, PPG-based ApEn and SampEn with appropriate k values have the potential to offer good quantification of analgesia depth under general anesthesia.

Photoplethysmography Response to Laryngeal Mask Airway Insertion during Propofol-Remifentanil Anethesia

The present study was aimed to evaluate the abilities of photoplethysmography (PPG)-derived parameters, including sample entropy of PPG (SampEn), amplitude of PPG (PPGA), pulse beat interval (PBI) and diastolic interval (DI) extracted by nonlinear or linear methods, to monitor the balance between nociception and antinociception. 26 ASA I or II patients were randomized into one of the three groups to receive a remifentanil effect-compartment target controlled infusion (Ce_remi) of 1, 3 and 5 ng/ml and an effect-compartment target controlled propofol infusion (Ce_prop) to keep the state entropy (SE) at 50 (40~60). Laryngeal mask airway (LMA) insertion was applied as a noxious stimulus. The percentage of change in SampEn (△SampEn, AUC=0.896), PBI (△PBI, AUC=0.896) and DI (ΔDI, AUC=0.972), but not in PPGA (△PPGA, AUC=0.667), were statistically excellent in discriminating low Ce_remi (1 ng/ml) from higher Ce_remi (3 and 5 ng/ml). Additionally, the prediction probabilities (P_k) values of △SampEn, ΔPBI and ΔDI were high as well with 0.795, 0.754 and 0.813 for discriminating Ce_remi. These results demonstrated that nonlinear and linear parameters of SampEn, PBI and DI had strong dependency on Ce_remi in response to LMA insertion and could provide nociceptive information during propofol-remifentanil anesthesia. This indicated that PPG-derived parameters were potential to develop the clinical assessment of nociception-antinociception balance under general anesthesia.

An injectable thermosensitive hydrogel loaded with an ancient natural drug colchicine for myocardial repair after infarction

Localized administration of anti-inflammatory agents benefits patients after myocardial infarction (MI) by repressing/modulating inflammatory response of the MI region and thus accelerating repair of the impaired tissues. Colchicine (Col), an ancient natural drug, has excellent anti-inflammatory effects; however, its utilization is strictly limited due to its severe systemic toxicity and narrow therapeutic window. In this study, we developed an intramyocardial delivery system of Col using an injectable, thermosensitive poly(lactide-co-glycolide)-poly(ethylene glycol)-poly(lactide-co-glycolide) (PLGA-PEG-PLGA) polymer hydrogel as the vehicle for the treatment of MI while minimizing its systemic toxicity. The aqueous PLGA-PEG-PLGA solution loaded with Col (Col@Gel) underwent a sol-gel transition at 35 °C and maintained a gel state at body temperature. Col was released from the Col@Gel in an initial burst followed by a sustained release manner for over 8 days. The in vitro cell tests showed that the Col@Gel system significantly inhibited macrophage proliferation and migration. In a mouse model of MI, a single intramyocardial administration of the Col@Gel effectively alleviated cardiac inflammation, inhibited myocardial apoptosis and fibrosis, improved cardiac function and structure, and increased mouse survival without inducing severe systemic toxicity, which was observed following intraperitoneal administration of Col solution. These results suggested that the Col@Gel system is a reliable drug delivery system for the sustained local release of Col and has great potential as an anti-inflammatory therapy for the treat of MI.

Feasibility of diffusion and probabilistic white matter analysis in patients implanted with a deep brain stimulator

Deep brain stimulation (DBS) for Parkinson's disease (PD) is an established advanced therapy that produces therapeutic effects through high frequency stimulation. Although this therapeutic option leads to improved clinical outcomes, the mechanisms of the underlying efficacy of this treatment are not well understood. Therefore, investigation of DBS and its postoperative effects on brain architecture is of great interest. Diffusion weighted imaging (DWI) is an advanced imaging technique, which has the ability to estimate the structure of white matter fibers; however, clinical application of DWI after DBS implantation is challenging due to the strong susceptibility artifacts caused by implanted devices. This study aims to evaluate the feasibility of generating meaningful white matter reconstructions after DBS implantation; and to subsequently quantify the degree to which these tracts are affected by post-operative device-related artifacts. DWI was safely performed before and after implanting electrodes for DBS in 9 PD patients. Differences within each subject between pre- and post-implantation FA, MD, and RD values for 123 regions of interest (ROIs) were calculated. While differences were noted globally, they were larger in regions directly affected by the artifact. White matter tracts were generated from each ROI with probabilistic tractography, revealing significant differences in the reconstruction of several white matter structures after DBS. Tracts pertinent to PD, such as regions of the substantia nigra and nigrostriatal tracts, were largely unaffected. The aim of this study was to demonstrate the feasibility and clinical applicability of acquiring and processing DWI post-operatively in PD patients after DBS implantation. The presence of global differences provides an impetus for acquiring DWI shortly after implantation to establish a new baseline against which longitudinal changes in brain connectivity in DBS patients can be compared. Understanding that post-operative fiber tracking in patients is feasible on a clinically-relevant scale has significant implications for increasing our current understanding of the pathophysiology of movement disorders, and may provide insights into better defining the pathophysiology and therapeutic effects of DBS.

Low-loss and broadband silicon mode filter using cascaded plasmonic BSWGs for on-chip mode division multiplexing

A mode splitter is a key device to eliminate undesired modes but allow desired modes go through for an on-chip mode-division multiplexing (MDM) system. Here, we propose a silicon high-order mode (HOM) pass filter based on the cascaded plasmonic bridged subwavelength gratings (BSWGs). A metal bridge is introduced to generate a plasmonic hybrid mode, which has a significant influence on the fundamental mode but a neglected impact on the first-order mode. A silicon HOM-pass filter for handling the TM₀ and TM₁ modes is optimized by using the 3D full-vectorial finite difference time domain (3D-FV-FDTD) method. The numerically simulated results indicate that the optimized mode filter is with a low loss of 0.63 dB and a mode extinction ratio (ER) of 26.4 dB based on 4-cascaded plasmonic BSWGs. The 3 dB bandwidth is over 493 nm from 1222 nm to 1715 nm. With the mode ER > 15.0 dB, a broad bandwidth of 150 nm can be achieved. The performance of the proposed mode filter is tolerant to the width error of ± 50 nm. The proposed silicon HOM-pass filter can be utilized in on-chip MDM systems for mode controlling.

1176Hepatocyte growth factor has prognostic utility in light chain and transthyretin cardiac amyloidosis

Background

With the advent of multiple novel therapeutics for light chain (AL) and transthyretin (ATTR) amyloidosis, there is a critical need for validated prognostic markers in cardiac amyloidosis. A discriminatory serum biomarker may improve prognostic and staging systems in AL and ATTR cardiac amyloidosis.

Purpose

Our objective was to test the hypothesis that hepatocyte growth factor (HGF) is associated with clinical outcomes in patients with AL and ATTR cardiac amyloidosis.

Methods

102 patients with AL or ATTR and suspected cardiac involvement were prospectively enrolled. HGF, NT-proBNP, troponin-T, and eGFR were measured upon study enrollment. Cardiac involvement was established by 1) endomyocardial biopsy, or 2) non-cardiac biopsy with concentric hypertrophy on echocardiography, low voltage or pseudo-infarction on ECG, elevated NT-proBNP or troponin-T, or characteristic delayed myocardial enhancement on cardiac MRI. Patients were followed for the occurrence of all-cause mortality, cardiac transplantation, and left-ventricular assist device implantation.

Results

Of the total amyloidosis cohort, 72 had cardiac involvement while 30 had non-cardiac disease. HGF, NT-proBNP, and troponin-T levels were significantly higher in patients with cardiac involvement than in patients with non-cardiac disease (p<0.05 for all comparisons). Over a median follow-up period of 1.9 years there were 20 deaths, 1 cardiac transplant, and 1 left-ventricular assist device implant, all in patients with cardiac involvement. Patient stratification by cut-off levels of NT-proBNP (332 pg/mL), troponin-T (35 ng/L), and eGFR (45 mL/min/1.73m2) used in published staging models for AL and ATTR cardiac amyloidosis showed no association between abnormal biomarker level and adverse clinical outcome (p>0.05). In contrast, stratification by HGF level of 310 pg/mL (identified by the Youden Index for cardiac involvement by AL and ATTR in our cohort) showed that elevated HGF was associated with worse clinical outcomes (p=0.0211). Furthermore, event-free survival was worse in patients with elevated HGF, with survival curves diverging soon after enrollment (p=0.0730).

HGF is Prognostic in Cardiac Amyloidosis

Conclusions

Elevated HGF is associated with worse clinical outcomes in patients with AL and ATTR cardiac amyloidosis and has potential for clinical utility.

Risk factors of hemorrhagic transformation after intravenous thrombolysis with rt-PA in acute cerebral infarction

BACKGROUND

Intravenous thrombolysis is considered to be the standard reperfusion therapy for acute ischemic stroke, but its application is limited by high risk of hemorrhagic transformation (HT) after thrombolysis.

AIM

This study aimed to identify risk factors of HT after intravenous thrombolysis.

METHODS

Patients with acute ischemic stroke receiving rt-PA thrombolysis from February 2013 to January 2018 were retrospectively reviewed. They were divided into HT group and non-HT group based on cranial computed tomography. Data of all patients were collected and analysed by univariate analysis and stepwise logistic regression analysis.

RESULTS

A total of 403 patients were enrolled and their age ranged from 13 to 86 years, with an average age of 67.01 ± 31.88 years. 136 (33.7%) patients were females. The average time from disease onset to thrombolysis was 52.05 ± 20.12 min, and 46 patients (11.4%) had HT after thrombolysis. We found significant differences in activated partial thromboplastin time, fibrinogen value, platelet value and smoking before thrombolysis between HT and non-HT group (P < 0.05).

CONCLUSION

Smoking, prolongation of activated partial thromboplastin time, low fibrinogen levels and low platelet counts are associated with the risk of HT and could help the selection of thrombolytic patients to avoid HT.

[In vivo characteristics of spinal kinematics in senile degenerative lumbar spondylolysis]

Objective: To investigate the in vivo kinematics of the lumbar degenerative spondylolysis (LDS) in senile patients. Methods: From March to October in 2014, nine L(4-5) LDS patients [mean age (74±9) years] and nine healthy volunteers [mean age, (54±4) years] were recruited. Combined fluoroscopy and CT scanning technique were used to obtain the three dimension kinematic data of the vertebral anatomical structures (vertebral body anterior margin, vertebral body posterior margin, facet joints and spinous process) in various postures (supine, standing, flexion and extension) under physical loads, and to compare the stability of different anatomical structures. The L(4-5) segmental disc angle was also measured in different postures. Paired-samples t test was applied to compare the displacement differences between the two groups. Results: During flexion-extension motion, all anatomical structures of the LDS group were slightly larger than those in normal group, but the statistical difference was not obvious (all P>0.05). For normal group, in anterior-posterior and cranial-caudal direction, sub-movement analysis showed that the anterior vertebral body margin at the flexion range of motion [(-1.07±0.84) mm, (-1.27±1.01) mm] were larger than the extension range of motion [(0.66±1.38) mm, (0.63±0.99) mm] (t=3.21, 4.03, both P<0.05). Whereas for LDS group, in anterior-posterior and cranial-caudal direction, sub-movement analysis showed that the anterior vertebral body margin at the extension range of motion [(1.46±1.26) mm, (1.17±0.54) mm] were significantly greater than the flexion range of motion [(-0.43±0.47) mm, (-0.45±1.24) mm] (t=4.22, 3.59, both P<0.05). The disc angles of the LDS group were all smaller than those in normal group, but the statistical difference was not obvious (all P>0.05). However, the disc angles were significantly different under different postures, the flexion were both the smallest in the normal group and LDS group. Conclusions: The senile LDS patients may not necessarily have instability, stability may also occur in these patients. Increasing extension range of motion is one of the kinematic characteristics in senile patients with LDS. The intervertebral stability should be taken into account, but if instability develops, surgical procedure should be suggested for elderly patients with LDS.

Anti-epidermal growth factor receptor (EGFR) monoclonal antibody combined with cisplatin and 5-fluorouracil in patients with metastatic nasopharyngeal carcinoma after radical radiotherapy: a multicentre, open-label, phase II clinical trial

BACKGROUND

We conducted a single-arm phase II trial to evaluate the efficacy and adverse effects (AEs) of an anti-epidermal growth factor receptor monoclonal antibody, nimotuzumab, combined with cisplatin and 5-fluorouracil (PF) as first-line treatment in recurrent metastatic nasopharyngeal carcinoma after radical radiotherapy.

METHODS

Patients who met the eligibility criteria were recruited from ten institutions (ClinicalTrials.gov; NCT01616849). A Simon optimal two-stage design was used to calculate the sample size. All patients received weekly nimotuzumab (200 mg) added to cisplatin (100 mg/m2 D1) and 5-fluorouracil (4 g/m2 continuous infusion D1-4) every 3-weekly for a maximum of six cycles. Primary end point was objective response rate (ORR). Secondary end points included disease control rate (DCR), progression-free survival (PFS), overall survival (OS) and AEs.

RESULTS

A total of 35 patients were enrolled (13 in stage 1 and 22 in stage 2). Overall ORR and DCR were 71.4% (25/35) and 85.7% (30/35), respectively. Median PFS and OS were 7.0 (95% CI 5.8-8.2) months and 16.3 (95% CI 11.4-21.3) months, respectively. Unplanned exploratory analyses suggest that patients who received ≥2400 mg nimotuzumab and ≥4 cycles of PF had superior ORR, PFS and OS than those who did not (88.9% versus 12.5%, P < 0.001; 7.4 versus 2.7 months, P = 0.081; 17.0 versus 8.0 months, P = 0.202). Favourable subgroups included patients with lung metastasis [HROS 0.324 (95% CI 0.146-0.717), P = 0.008] and disease-free interval of >12 months [HROS 0.307 (95% CI 0.131-0.724), P = 0.004], but no difference was observed for metastatic burden. The only major grade 3/4 AE was leukopenia (62.9%).

CONCLUSION

Combination nimotuzumab-PF chemotherapy demonstrates potential efficacy, and is well tolerated as first-line chemotherapy regimen in recurrent metastatic nasopharyngeal carcinoma.

A novel parameter derived from photoplethysmographic pulse wave to distinguish preeclampsia from non-preeclampsia

OBJECTIVE

To describe the comparative hierarchical area ratio (CHAR), a novel parameter derived from the photoplethysmographic (PPG) pulse wave and differences in CHAR values in parturients with and without preeclampsia (PE).

METHODS

A total of 59 parturients (37 without and 22 with PE) was conducted at the Women's Hospital, Zhejiang University, School of Medicine in Hangzhou, China. We calculated the CHAR values derived from the PPG pulse wave and compared them in parturients with and without PE.

RESULT

The values of CHAR derived from the parturients with PE were lower compared to those without PE (p < 0.01). The ROC analysis indicated that the best threshold for the mean value of CHAR was 7.92 to predict PE with a sensitivity of 86.4% and a specificity of 87.1%, while the threshold for the standard deviation of CHAR was 0.76 with a sensitivity of 77.3% and a specificity of 77.4%. The area under the curve (AUC) was 0.91 for mean value of CHAR while 0.78 for standard deviation of CHAR. Meanwhile, a contrast of AUC between CHAR and the former parameter we proposed showed CHAR had better performance in distinguishing PE (0.908 over 0.615, p < 0.01).

CONCLUSION

The novel parameter, CHAR, derived from PPG pulse wave differs in parturients with and without PE with high sensitivity and specificity, suggesting that the CHAR might be an effective tool in differentiating the presence of PE.

Abstract P1-17-03: Statin use, site of recurrence, and survival among post-menopausal women taking bisphosphonates as adjuvant therapy for breast cancer (SWOG S0307)

Purpose: Statins may mediate suppression of molecular pathways conferring benefit in cancer. Statins have shown anti-tumor effects in preclinical studies and have been associated with decreased recurrence and improved disease-specific survival. While designed to target cholesterol biosynthesis, statins can also have liver, bone and brain effects. We collected data on statin use in the S0307 adjuvant bisphosphonate trial to test the hypothesis that statin use may decrease risk of recurrence to liver, bone and brain as well as second primary (contralateral) breast cancers, and may act synergistically with bisphosphonates to decrease the risk of recurrence to bone.

Patients and Methods: In S0307, 6097 patients diagnosed with Stage I-III breast cancer who had undergone surgery and were receiving adjuvant systemic therapy were randomized to receive zoledronic acid, clodronate, or ibandronate for 3 years. No significant difference was found in disease-free survival (DFS) among the 3 groups, including a sub-analysis of patients &gt; age 55. Statin use was infrequent in younger women in S0307, consequently we analyzed statin use in those &gt; age 55. Cox proportional hazard models were used to determine which variables were independently associated with DFS and to estimate hazard ratios (HR) and 95% confidence intervals (CI).

Results: Among women aged ≥ 55 years, 684 (27%) reported taking a statin at baseline and 1,848 did not. Both groups were similar in terms of hormone receptor and HER2 status (p = 0.82). Median age in the statin group was 64.3 versus 61.0 years in the no statin group, mean BMI 31.2 v. 29.5, mean tumor size 2.1cm v. 2.3cm, negative lymph nodes 60% v. 54%, Stage I disease 47% v. 36%, and receipt of chemotherapy 62% v. 71% (all p &lt; 0.01). In the statin group, 122 (17.8%) experienced a DFS event compared to 313 (16.9%) in the no statin group (HR 1.18, CI 0.95-1.46). No difference was observed by statin use in overall recurrence (p=0.28), distant recurrence (p=0.64), or recurrences to the bone (p=0.64), liver (p=0.38) or brain (p=0.65) at initial recurrence. There was no synergy between statin use and specific bisphosphonates.

Recurrence and statin useOutcomeGroup 1: On stan at baseline n=684Group 2: No statin at baseline n=1848DFS events122 (17.8%)313 (16.9%)Died without recurrence51 7.5%)97 (5.2%)Recurrence71 (10.4%)216 (11.7%)Contralateral breast cancer9 (1.3%)17 (0.9%)Distant recurrence48 (7%)157 (8.5%)Bone as 1st site of distant recurrence (% distant recurrence)31 (65%)76 (48%)Liver as 1st site of distant recurrence (% distant recurrence)6 (13%)24 (16%)Brain/CNS as 1st site of distant recurrence (% distant recurrence)5 (10%)17 (11%)

Conclusions: We found no evidence that statins reduce risk of second primary breast cancers or distant metastases among post-menopausal women with early-stage breast cancer. Despite promising preclinical data, they did not appear to act in synergy with a specific bisphosphonate. Though women in the statin group had less advanced disease at study entry, statin use was not associated with improved DFS. Results are limited by lack of information about type of statin used, adherence, or initiation of statin in control group.

Citation Format: Kizub D, Miao J, Stopeck A, Thompson P, Paterson AH, Clemons M, Dees EC, Ingle JN, Falkson CI, Barlow W, Hortobagyi GN, Gralow JR. Statin use, site of recurrence, and survival among post-menopausal women taking bisphosphonates as adjuvant therapy for breast cancer (SWOG S0307) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-17-03.

Predicting the hearing outcome in sudden sensorineural hearing loss via machine learning models

OBJECTIVE

Sudden sensorineural hearing loss (SSHL) is a multifactorial disorder with high heterogeneity, thus the outcomes vary widely. This study aimed to develop predictive models based on four machine learning methods for SSHL, identifying the best performer for clinical application.

DESIGN

Single-centre retrospective study.

SETTING

Chinese People's liberation army (PLA) hospital, Beijing, China.

PARTICIPANTS

A total of 1220 in-patient SSHL patients were enrolled between June 2008 and December 2015.

MAIN OUTCOME MEASURES

An advanced deep learning technique, deep belief network (DBN), together with the conventional logistic regression (LR), support vector machine (SVM) and multilayer perceptron (MLP) were developed to predict the dichotomised hearing outcome of SSHL by inputting six feature collections derived from 149 potential predictors. Accuracy, precision, recall, F-score and the area under the receiver operator characteristic curves (ROC-AUC) were exploited to compare the prediction performance of different models.

RESULTS

Overall the best predictive ability was provided by the DBN model when tested in the raw data set with 149 variables, achieving an accuracy of 77.58% and AUC of 0.84. Nevertheless, DBN yielded inferior performance after feature pruning. In contrast, the LR, SVM and MLP models demonstrated opposite trend as the greatest individual prediction powers were obtained when included merely three variables, with the ROC-AUC ranging from 0.79 to 0.81, and then decreased with the increasing size of input features combinations.

CONCLUSIONS

With the input of enough features, DBN can be a robust prediction tool for SSHL. But LR is more practical for early prediction in routine clinical application using three readily available variables, that is time elapse between symptom onset and study entry, initial hearing level and audiogram.

Photoexcited Muon Spin Spectroscopy: A New Method for Measuring Excess Carrier Lifetime in Bulk Silicon

We have measured excess carrier lifetime in silicon using photoexcited muon spin spectroscopy. Positive muons implanted deep in a wafer can interact with the optically injected excess carriers and directly probe the bulk carrier lifetime while minimizing the effect from surface recombination. The method is based on the relaxation rate of muon spin asymmetry, which depends on the excess carrier density. The underlying microscopic mechanism has been understood by simulating the four-state muonium model in Si under illumination. We apply the technique to different injection levels and temperatures, and demonstrate its ability for injection- and temperature-dependent lifetime spectroscopy.