Cough flows as a criterion for decannulation of autonomously breathing patients with tracheostomy tubes

BACKGROUND

Adequate cough or exsufflation flow can indicate an option for safe tracheostomy decannulation to noninvasive management. Cough peak flow via the upper airways with the tube capped is an outcome predictor for decannulation readiness in patients with neuromuscular impairment. However, this threshold value is typically measured with tracheotomy tube removed, which is not acceptable culturally in China. The aim of this study was to assess the feasibility and safety of using cough flow measured with tracheostomy tube and speaking valve (CFSV) > 100 L/min as a cutoff value for decannulation.

STUDY DESIGN

Prospective observational study conducted between January 2019 and September 2022 in a tertiary rehabilitation hospital.

METHODS

Patients with prolonged tracheostomy tube placement were referred for screening. Each patient was assessed using a standardized tracheostomy decannulation protocol, in which CFSV greater than 100 L/min indicated that the patients' cough ability was sufficient for decannulation. Patients whose CFSV matched the threshold value and other protocol criteria were decannulated, and the reintubation and mortality rates were followed-up for 6 months.

RESULTS

A total of 218 patients were screened and 193 patients were included. A total of 105 patients underwent decannulation, 103 patients were decannulated successfully, and 2 patients decannulated failure, required reinsertion of the tracheostomy tube within 48 h (failure rate 1.9%). Three patients required reinsertion or translaryngeal intubation within 6 months.

CONCLUSIONS

CFSV greater than 100 L/min could be a reliable threshold value for successful decannulation in patients with various primary diseases with a tracheostomy tube.

TRIAL REGISTRATION

This observational study was not registered online.

Improving Bond Strength of Translucent Zirconia Through Surface Treatment With SiO2-ZrO2 Coatings

BACKGROUND

Translucent monolithic zirconia ceramics have been applied in dental clinics due to their esthetic translucent formulations and mechanical properties. Considering inherent ceramic brittleness, adhesive bonding with resin composite increases the fracture resistance of ceramic restorations. However, zirconia is a chemically stable material that is difficult to adhesively bond with resin.

OBJECTIVES

To investigate the influences of SiO2-ZrO2 coatings on adhesive bonding of zirconia and the surface characterization of those coatings.

METHODS AND MATERIALS

Translucent zirconia discs were classified into groups based on surface treatments: CT (control), SB (sandblasting), C21(SiO2:ZrO2=2:1), C11(SiO2:ZrO2=1:1), and C12 (SiO2:ZrO2=1:2) (n=10). Surface characterization of coatings on zirconia were analyzed by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), surface roughness assessment (Ra), X-ray diffraction (XRD), water contact angle (WCA), translucency parameter (TP), and shear bond strength (SBS). Two-way ANOVA for shear bond strength results and ANOVA for Ra and WCA were performed.

RESULTS

SEM images revealed SiO2 islands on zirconia disks coated with SiO2-ZrO2. Surface roughness of C12, C11, and C21 groups was significantly larger than those of groups SB and CT (p<0.05). XRD results showed that phase transformation of zirconia disks was detected only in the SB group. In addition, SiO2-ZrO2 coatings reduced WCA. The translucency decreased only in group C21. Group C11 showed the highest shear bond strength under both aging conditions.

CONCLUSION

SiO2-ZrO2 coating is a promising method to enhance the adhesive resin bonding of translucent zirconia without causing phase transformation of translucent zirconia.

Learning Intention-Aware Policies in Deep Reinforcement Learning

Deep reinforcement learning (DRL) provides an agent with an optimal policy so as to maximize the cumulative rewards. The policy defined in DRL mainly depends on the state, historical memory, and policy model parameters. However, we humans usually take actions according to our own intentions, such as moving fast or slow, besides the elements included in the traditional policy models. In order to make the action-choosing mechanism more similar to humans and make the agent to select actions that incorporate intentions, we propose an intention-aware policy learning method in this letter To formalize this process, we first define an intention-aware policy by incorporating the intention information into the policy model, which is learned by maximizing the cumulative rewards with the mutual information (MI) between the intention and the action. Then we derive an approximation of the MI objective that can be optimized efficiently. Finally, we demonstrate the effectiveness of the intention-aware policy in the classical MuJoCo control task and the multigoal continuous chain walking task.

Superhydrophobic, stretchable kirigami pencil-on-paper multifunctional device platform

Wearable electronics with applications in healthcare, human-machine interfaces, and robotics often explore complex manufacturing procedures and are not disposable. Although the use of conductive pencil patterns on cellulose paper provides inexpensive, disposable sensors, they have limited stretchability and are easily affected by variations in the ambient environment. This work presents the combination of pencil-on-paper with the hydrophobic fumed SiO₂ (Hf-SiO₂) coating and stretchable kirigami structures from laser cutting to prepare a superhydrophobic, stretchable pencil-on-paper multifunctional sensing platform. The resulting sensor exhibits a large response to NO₂ gas at elevated temperature from self-heating, which is minimally affected by the variations in the ambient temperature and relative humidity, as well as mechanical deformations such as bending and stretching states. The integrated temperature sensor and electrodes with the sensing platform can accurately detect temperature and electrophysiological signals to alert for adverse thermal effects and cardiopulmonary diseases. The thermal therapy and electrical stimulation provided by the platform can also deliver effective means to battle against inflammation/infection and treat chronic wounds. The superhydrophobic pencil-onpaper multifunctional device platform provides a low-cost, disposable solution to disease diagnostic confirmation and early treatment for personal and population health.

Vanadium Oxide-Doped Laser-Induced Graphene Multi-Parameter Sensor to Decouple Soil Nitrogen Loss and Temperature

Monitoring nitrogen utilization efficiency and soil temperature in agricultural systems for timely intervention is essential for crop health with reduced environmental pollution. Herein, this work presents a high-performance multi-parameter sensor based on vanadium oxide (VOX )-doped laser-induced graphene (LIG) foam to completely decouple nitrogen oxides (NOX ) and temperature. The highly porous 3D VOX -doped LIG foam composite is readily obtained by laser scribing vanadium sulfide (V5 S8 )-doped block copolymer and phenolic resin self-assembled films. The heterojunction formed at the LIG/VOX interface provides the sensor with enhanced response to NOX and an ultralow limit of detection of 3 ppb (theoretical estimate of 451 ppt) at room temperature. The sensor also exhibits a wide detection range, fast response/recovery, good selectivity, and stability over 16 days. Meanwhile, the sensor can accurately detect temperature over a wide linear range of 10-110 °C. The encapsulation of the sensor with a soft membrane further allows for temperature sensing without being affected by NOX . The unencapsulated sensor operated at elevated temperature removes the influences of relative humidity and temperature variations for accurate NOX measurements. The capability to decouple nitrogen loss and soil temperature paves the way for the development of future multimodal decoupled electronics for precision agriculture and health monitoring.

Pencil-on-Paper Humidity Sensor Treated with NaCl Solution for Health Monitoring and Skin Characterization

Although flexible humidity sensors are essential for human health monitoring, it is still challenging to achieve high sensitivity and easy disposal with simple, low-cost fabrication processes. This study presents the design and fabrication of highly reliable hand-drawn interdigital electrodes from pencil-on-paper treated with NaCl solution for highly sensitive hydration sensors working over a wide range of relative humidity (RH) levels from 5.6% to 90%. The applications of the resulting flexible humidity sensor go beyond the monitoring of respiratory rate and proximity to characterizations of human skin types and evaluations of skin barrier functions through insensible sweat measurements. The sensor array can also be integrated with a diaper to result in smart diapers to alert for an early diaper change. The design and fabrication strategies presented in this work could also be leveraged for the development of wearable, self-powered, and recyclable sensors and actuators in the future.

Intrinsically Breathable and Flexible NO2 Gas Sensors Produced by Laser Direct Writing of Self-Assembled Block Copolymers

The surge in air pollution and respiratory diseases across the globe has spurred significant interest in the development of flexible gas sensors prepared by low-cost and scalable fabrication methods. However, the limited breathability in the commonly used substrate materials reduces the exchange of air and moisture to result in irritation and a low level of comfort. This study presents the design and demonstration of a breathable, flexible, and highly sensitive NO₂ gas sensor based on the silver (Ag)-decorated laser-induced graphene (LIG) foam. The scalable laser direct writing transforms the self-assembled block copolymer and resin mixture with different mass ratios into highly porous LIG with varying pore sizes. Decoration of Ag nanoparticles on the porous LIG further increases the specific surface area and conductivity to result in a highly sensitive and selective composite to detect nitrogen oxides. The as-fabricated Ag/LIG gas sensor on a flexible polyethylene substrate exhibits a large response of -12‰, a fast response/recovery of 40/291 s, and a low detection limit of a few parts per billion at room temperature. Integrating the Ag/LIG composite on diverse fabric substrates further results in breathable gas sensors and intelligent clothing, which allows permeation of air and moisture to provide long-term practical use with an improved level of comfort.

A Hierarchical Bayesian Latent Class Model for the Diagnostic Performance of Mini-Mental State Examination and Montreal Cognitive Assessment in Screening Mild Cognitive Impairment Due to Alzheimer's Disease

BACKGROUND

The Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) are low costing and noninvasive neuropsychological tests in screening Mild Cognitive Impairment (MCI) due to Alzheimer's disease (AD). There is no consensus on which test performs better in detecting MCI due to AD based on the different imperfect reference standards. Therefore, we conducted a meta-analysis to assess the diagnostic performance of MMSE and MoCA for screening MCI due to AD in the absence of a gold standard.

METHODS

Six electronic databases were searched for relevant studies until April, 2022. A hierarchical Bayesian latent class model was used to estimate the pooled sensitivity and specificity of MoCA and MMSE in the absence of a gold standard.

RESULTS

90 eligible studies covering 21273 individuals for MMSE, 26631 individuals for MoCA were included in this meta-analysis. The pooled sensitivity was 0.71(95%CI: 0.67-0.74) for MMSE and 0.85(95%CI: 0.83-0.88) for MoCA, while the pooled specificity was 0.71(95%CI: 0.68-0.74) for MMSE and 0.79(95%CI: 0.76-0.81) for MoCA. MoCA was useful to "rule in" and "rule out" the diagnosis of MCI due to AD with higher positive likelihood ratio (4.07; 95%CI: 3.60-4.62) and lower negative likelihood ratio (0.18; 95%CI: 0.16-0.22). Moreover, the diagnostic odds ratio of MoCA was 22.08(95%CI: 17.24-28.29), which showed significantly favorable diagnostic performance.

CONCLUSIONS

It suggests that MoCA has greater diagnostic performance than MMSE for differentiating MCI due to AD when the gold standard is absent. However, these results should be taken with caution given the heterogeneity observed.

Moisture-resistant, stretchable NOx gas sensors based on laser-induced graphene for environmental monitoring and breath analysis

The accurate, continuous analysis of healthcare-relevant gases such as nitrogen oxides (NO_x) in a humid environment remains elusive for low-cost, stretchable gas sensing devices. This study presents the design and demonstration of a moisture-resistant, stretchable NO_x gas sensor based on laser-induced graphene (LIG). Sandwiched between a soft elastomeric substrate and a moisture-resistant semipermeable encapsulant, the LIG sensing and electrode layer is first optimized by tuning laser processing parameters such as power, image density, and defocus distance. The gas sensor, using a needlelike LIG prepared with optimal laser processing parameters, exhibits a large response of 4.18‰ ppm^-1 to NO and 6.66‰ ppm^-1 to NO₂, an ultralow detection limit of 8.3 ppb to NO and 4.0 ppb to NO₂, fast response/recovery, and excellent selectivity. The design of a stretchable serpentine structure in the LIG electrode and strain isolation from the stiff island allows the gas sensor to be stretched by 30%. Combined with a moisture-resistant property against a relative humidity of 90%, the reported gas sensor has further been demonstrated to monitor the personal local environment during different times of the day and analyze human breath samples to classify patients with respiratory diseases from healthy volunteers. Moisture-resistant, stretchable NO_x gas sensors can expand the capability of wearable devices to detect biomarkers from humans and exposed environments for early disease diagnostics.

Wearable Pressure Sensors Based on MXene/Tissue Papers for Wireless Human Health Monitoring

Though the widely available, low-cost, and disposable papers have been explored in flexible paper-based pressure sensors, it is still difficult for them to simultaneously achieve ultrahigh sensitivity, low limit and broad range of detection, and high-pressure resolution. Herein, we demonstrate a novel flexible paper-based pressure sensing platform that features the MXene-coated tissue paper (MTP) sandwiched between a polyimide encapsulation layer and a printing paper with interdigital electrodes. After replacing the polyimide with weighing paper in the MTP pressure sensor, the silver interdigital electrodes can be recycled through incineration. The resulting pressure sensor with polyimide or paper encapsulation exhibits a high sensitivity of 509.5 or 344.0 kPa^-1, a low limit (∼1 Pa) and a broad range (100 kPa) of detection, and outstanding stability over 10 000 loading/unloading cycles. With ultrahigh sensitivity over a wide pressure range, the flexible pressure sensor can monitor various physiological signals and human movements. Configuring the pressure sensors into an array layout results in a smart artificial electronic skin to recognize the spatial pressure distribution. The flexible pressure sensor can also be integrated with signal processing and wireless communication modules on a face mask as a remote respiration monitoring system to wirelessly detect various respiration conditions and respiratory abnormalities for early self-identification of opioid overdose, pulmonary fibrosis, and other cardiopulmonary diseases.

Ventilation improvement after pneumonia treatment evaluated with electrical impedance tomography: an observational study

OBJECTIVE

Due to radiation exposures, not all patients with pneumonia would receive chest x-ray or CT measurements to confirm treatment effectiveness. The aim of the study was to examine the ability of using electrical impedance tomography (EIT) to evaluate the treatment effectiveness in such patient group.

METHODS

A total of 35 consecutive patients with non-severe pneumonia was included in this prospective study. The patients received standard treatment according to our internal protocol. EIT measurements were performed in supine position before the treatment start and on day 6 of the treatment period. EIT-based global inhomogeneity (GI) index and center of ventilation index (CoV) were calculated. Clinical pulmonary infection score (CPIS) was obtained at both time points.

RESULTS

Clinically significant improvements in GI and CoV were found in patient group (ΔGI: -34%±17% and ΔCoV: -10%±11%; p<0.001). Although CPIS was also significantly improved (ΔCPIS -0.70±0.17, p<0.001), no correlations were demonstrated when it compared to ΔGI or ΔCoV.

CONCLUSION

EIT demonstrated individual improvement of ventilation heterogeneity after standard treatment in non-severe pneumonia, which provided different information compared to CPIS. EIT has the potential to become a routine non-invasive, non-radiative tool to assess pneumonia treatment effectiveness.

Characterizing the air pollution of the cities in the closure of corona virus disease 2019 in China

With the rapid development of industrialization and urbanization in China, energy and vehicle consumption have continued to increase in recent years and air pollution has become serious. In early 2020, Corona Virus Disease 2019 broke out in Wuhan, China. From January 29, 2020, several sources of the air pollution almost all stopped working, including gasoline burning vehicles, dust producing building sites, coal-fired factories, etc. Five indicators of the atmospheric environmental quality were observed from December 19, 2019 to April 30, 2020 in nine cities and 1-h average concentrations, 24-h average concentrations and Air Quality Index were assessed. The 1-h average concentrations of the nitrogen dioxide, the ozone and the sulfur dioxide showed obvious difference though the closure did not change the sequence of the five pollutants' concentrations in the air at diverse sampling moments. The changing of the 24-h average concentrations of the five pollutants indicated the amount of pollutants in the air were greatly affected by human activities. The nitrogen dioxide, the sulfur dioxide and the particulate matters decreased obviously in the closure. The air in the metropolis and the south-east cities were relatively clean and the pollutants' concentrations decreased slightly during the closure period. The northern and the heavy industrial cities showed significant drop on air pollution indicators and the air quality of the two city groups could be greatly improved if some effective measures could be taken of environmental management and regional development.

The influence of an electrical impedance tomography belt on lung function determined by spirometry in sitting position

OBJECTIVE

The aim of the study was to examine whether an electrical impedance tomography (EIT) electrode belt changed the lung function in healthy volunteers and patients with respiratory muscle weakness (RMW) and chronic obstructive pulmonary disease (COPD).

APPROACH

In total, thirty subjects were included (10 healthy volunteers, 10 subjects with RMW, maximum inspiratory pressure < 40 cmH₂O, and 10 COPD, grade I-IV). Spirometry measurements were conducted in a sitting position once a day at similar times on two consecutive days. Slow expiratory vital capacity (VC), forced vital capacity (FVC) and maximum voluntary ventilation (MVV) manoeuvres were performed. On day 1, spirometry was performed without the EIT electrode belt, and on day 2, the belt was attached to the thorax.

MAIN RESULTS

Lung function was not influenced by the electrode belt in healthy subjects. The test-retest reliability in the healthy group was 0.89, 0.89 and 0.85 for VC, FVC and MVV, respectively. On the other hand, all investigated parameters were significantly decreased in the RMW group (VC, 51.3 ± 18.0 versus 46.5 ± 18.0% predicted, without versus with EIT belt, p< 0.01; FVC, 51.7 ± 19.0 versus 45.8 ± 18.1% predicted, p< 0.01; MVV, 41.0 ± 20.0 versus 38.8 ± 19.6% predicted, p< 0.01). VC and MVV also decreased significantly in the COPD group (VC, 77.4 ± 20.5 versus 74.6 ± 18.8% predicted, p< 0.05; MVV, 57.4 ± 15.7 versus 54.4 ± 12.5% predicted, p< 0.05).

SIGNIFICANCE

An EIT electrode belt could reduce lung volumes in subjects with pre-existing lung diseases. Comparing lung function acquired with an electrode belt to corresponding values obtained without the belt should be avoided.

Graphene enhanced field emission from InP nanocrystals

We report the observation of field emission (FE) from InP nanocrystals (NCs) epitaxially grown on an array of p-Si nanotips. We prove that FE can be enhanced by covering the InP NCs with graphene. The measurements are performed inside a scanning electron microscope chamber with a nano-controlled W-thread used as an anode. We analyze the FE by Fowler-Nordheim theory and find that the field enhancement factor increases monotonically with the spacing between the anode and the cathode. We also show that InP/p-Si junction has a rectifying behavior, while graphene on InP creates an ohmic contact. Understanding the fundamentals of such nanojunctions is key for applications in nanoelectronics.

Electron holography on HfO2/HfO2-x bilayer structures with multilevel resistive switching properties

Unveiling the physical nature of the oxygen-deficient conductive filaments (CFs) that are responsible for the resistive switching of the HfO₂-based resistive random access memory (RRAM) devices represents a challenging task due to the oxygen vacancy related defect nature and nanometer size of the CFs. As a first important step to this goal, we demonstrate in this work direct visualization and a study of physico-chemical properties of oxygen-deficient amorphous HfO_2-x by carrying out transmission electron microscopy electron holography as well as energy dispersive x-ray spectroscopy on HfO₂/HfO_2-x bilayer heterostructures, which are realized by reactive molecular beam epitaxy. Furthermore, compared to single layer devices, Pt/HfO₂/HfO_2-x /TiN bilayer devices show enhanced resistive switching characteristics with multilevel behavior, indicating their potential as electronic synapses in future neuromorphic computing applications.

Puerarin prevents inflammation and apoptosis in the neurocytes of a murine Parkinson's disease model

The aim of this study was to investigate Parkinson's disease (PD) using a murine model of PD. Specifically, we aimed to explore the mechanism by which puerarin prevents inflammation and apoptosis in neurocytes. Eighty healthy male C57/BL6 mice were randomly selected and divided into four groups (N = 20 each): control group; PD group; PD+puerarin group; and puerarin group. At the end of the treatment period, the animals' brains were removed after perfusion and decollation. The protein expression levels of tyrosine hydroxylase (TH) in the murine brains were assessed by immunohistochemistry and the protein expression levels of TH, glial fibrillary acidic protein (GFAP), inducible nitric oxide synthase (iNOS), cleaved Caspase-3, and Bax in the substantia nigra and corpus striatum of the animals were assessed by western blotting. The spontaneous activity of the PD mice was found to be significantly higher after puerarin treatment and the distance traveled by mice in an open field assessment was 1700 cm further in puerarin-treated PD mice than in PD mice. Immunohistochemistry and western blotting analyses indicated that the expression of TH was significantly higher (2.63-fold) in puerarin-treated PD mice than in untreated PD mice and that the expression of GFAP in PD mice was significantly reduced (~45%) by puerarin treatment. These findings lead us to conclude that puerarin significantly alleviates 1-methyl-4-phenyl- 1,2,3,6-tetrahydropyridine-induced injury in dopaminergic neurons. Puerarin mediates anti-apoptotic and anti-inflammatory activities and plays a neuroprotective role.

Vitamin D prevents articular cartilage erosion by regulating collagen II turnover through TGF-β1 in ovariectomized rats

OBJECTIVE

To explore the effect of vitamin D on turnover of articular cartilage with ovariectomy (OVX) induced OA, and to investigate transforming growth factor-β1 (TGF-β1) as a possible underlying mechanism mediated by 1α,25(OH)2D3.

DESIGN

Sixty-six rats were randomly allocated into seven groups: sham plus control diet (SHAM+CTL), OVX+CTL diet, sham plus vitamin D-deficient (VDD) diet, OVX+VDD diet, and three groups of ovariectomized rats treated with different doses of 1α,25(OH)2D3. The cartilage erosion and the levels of serum 17β-estradiol, 1α,25(OH)2D3 and C-telopeptide of type II collagen (CTX-II) were measured. TGF-β1, type II Collagen (CII), matrix metalloproteinases (MMP)-9,-13 in articular cartilage were assessed by immunohistochemistry. TGF-β1 and CTX-II expression were measured in articular cartilage chondrocytes treated with/without tumor necrosis factor (TNF-α), 1α,25(OH)2D3, and TGF-β receptor inhibitor (SB505124) in vitro.

RESULTS

Cartilage erosion due to OVX was significantly reduced in a dose-dependent manner by 1α,25(OH)2D3 supplementation, and exacerbated by VDD. The expressions of TGF-β1 and CII in articular cartilage were suppressed by OVX and VDD, and rescued by 1α,25(OH)2D3 supplementation. The expression of MMP-9,-13 in articular cartilage increased with OVX and VDD, and decreased with 1α,25(OH)2D3 supplementation. In vitro experiments showed that 1α,25(OH)2D3 increased the TGF-β1 expression of TNF-α stimulated chondrocytes in a dose-dependent manner. 1α,25(OH)2D3 significantly counteracted the increased CTX-II release due to TNF-α stimulation, and this effect was significantly suppressed by SB505124.

CONCLUSION

VDD aggravated cartilage erosion, and 1α,25(OH)2D3 supplementation showed protective effects in OVX-induced OA partly through the TGF-β1 pathway.

Post deposition annealing of epitaxial Ce1−xPrxO2−δfilms grown on Si(111)

In this work the structural and morphological changes of Ce_1−xPr_xO_2−δ(x= 0.20, 0.35 and 0.75) films grown on Si(111) due to post deposition annealing are investigated by low energy electron diffraction combined with a spot profile analysis.

Structural transitions of epitaxial ceria films on Si(111)

The structural changes of a (111) oriented CeO2 film grown on a Si(111) substrate covered with a hex-Pr2O3(0001) interface layer due to post deposition annealing are investigated. X-ray photoelectron spectroscopy measurements revealing the near surface stoichiometry show that the film reduces continuously upon extended heat treatment. The film is not homogeneously reduced since several coexisting crystalline ceria phases are stabilized due to subsequent annealing at different temperatures as revealed by high resolution low energy electron diffraction and X-ray diffraction. The electron diffraction measurements show that after annealing at 660 °C the ι-phase (Ce7O12) is formed at the surface which exhibits a (√7 × √7)R19.1° structure. Furthermore, a (√27 × √27)R30° surface structure with a stoichiometry close to Ce2O3 is stabilized after annealing at 860 °C which cannot be attributed to any bulk phase of ceria stable at room temperature. In addition, it is shown that the fully reduced ceria (Ce2O3) film exhibits a bixbyite structure. Polycrystalline silicate (CeSi(x)O(y)) and crystalline silicide (CeSi1.67) are formed at 850 °C and detected at the surface after annealing above 900 °C.

Insulator-metal transition of VO₂ ultrathin films on silicon: evidence for an electronic origin by infrared spectroscopy

We report on the first simultaneous observations of both electronic and structural temperature-induced insulator-to-metal transition (IMT) in VO2 ultrathin films, made possible by the use of broad range transmission infrared spectroscopy. Thanks to these techniques, the infrared phonon structures, as well as the appearance of the free carrier signature, were resolved for the first time. The temperature-resolved spectra allowed the determination of the temperature hysteresis for both the structural (monoclinic-to-rutile) and electronic (insulator-to-metallic) transitions. The combination of these new observations and DFT simulations for the monoclinic structure allows us to verify the direct transition from monoclinic (M1) to rutile and exclude an intermediate structural monoclinic form (M2). The delay in structural modification compared to the primer electronic transition (325 K compared to 304 K) supports the role of free charges as the transition driving force. The shape of the free charge hysteresis suggests that the primer electronic transition occurs first at 304 K, followed by both its propagation to the heart of the layer and the structural transition when T increases. This study outlines further the potential of VO2 ultrathin films integrated on silicon for optoelectronics and microelectronics.

Meta-analysis of temporary ileostomy versus colostomy for colorectal anastomoses

BACKGROUND/AIMS

Defunctioning stoma is a common surgical procedure, it is now generally acknowledged that defunctioning stoma significantly reduce the rates of complications in colorectal surgery, but the choice of temporary ileostomy or temporary colostomy for defunctioning colorectal anastomoses remains controversial. This meta-analysis evaluated two types of defunctioning stoma to determine whether one is superior to the other.

METHODOLOGY

Studies and relevant literatures comparing temporary ileostomy with temporary colostomy for defunctioning colorectal anastomoses were searched though PubMed, Embase and The Cochrane Library. The rates of complications were pooled and compared using a meta-analysis. The risk ratios were calculated with 95% confidence intervals to evaluate the safety and efficacy of each technique.

RESULTS

Five randomized controlled trials and seven non-randomized studies were included, with 1687 patients in total. The meta-analysis of the RCTs demonstrated a lower risk of stoma prolapse (RR 0.15; 95% CI: 0.04-0.48, p = 0.001) in the temporary ileostomy group. Meta-analysis of the non-randomized studies showed a lower risk of stoma prolapse (RR 0.26; 95% CI 0.10-0.67, p = 0.005) and wound infection after stoma closure (RR 0.28; 95% CI 0.5-0.52, p < 0.0001) in the temporary ileostomy group. No other statistically significant difference was observed for complications.

CONCLUSIONS

Each type of defunctioning stoma has its advantages and disadvantages, and there is not a strong evidence for the superiority of one temporary stoma over another for colorectal anastomoses. According to this, large scale RCTs and high quality studies are needed to conduct.

WE-C-217BCD-04: Multimodality Imaging of Breast Cancer Experimental Lung Metastasis

PURPOSE

Metastatic breast cancer (MBC) is incurable. The clinical gold standard for assessing tumor microvessel density (MVD), an independent prognostic marker in MBC, is CD 105 staining. The goal of this study is to develop a positron emission tomography (PET)/near-infrared fluorescent (NIRF) probe for imaging of CD105 expression in MBC (i.e. non-invasive measurement of MVD), as well as other applications such as early detection of metastasis, intraoperative guidance, etc.

METHODS

TRC105, a chimeric anti-CD105 mAb, was dual-labeled with a NIRF dye and ⁸⁹ Zr to yield ^{8 9} Zr-Df-TRC105-800CW. Luciferase-transfected 4T1 murine breast cancer cells were injected intravenously into female BALB/c mice to establish a lung MBC model. Bio luminescence imaging (BLI) was carried out to non- invasively monitor the lung tumor burden. Comprehensive in vivo/ex vivo studies were performed to investigate ^{8 9} Zr-Df-TRC105-800CW in this MBC model. Cetuximab was used as an isotype-matched control.

RESULTS

Radiolabeled TRC105 has high tumor uptake in many tumor types in addition to MBC (e.g. pancreatic/prostate cancer and brain tumor), revealing broad clinical potential for TRC105-based agents. FACS analysis of HUVECs showed no difference in CD 105 binding between TRC105 and Df- TRC105-800CW. PET imaging revealed that 4T1 lung tumor uptake of ⁸⁹ Zr-Df-TRC105-800CW was 8.7±1.4,10.9±0.5, and 9.7±1.1 %ID/g at 4, 24, and 48 h post-injection (n = 4), with excellent tumor contrast. Bio distribution studies, blocking, control studies with ^{8 9} Zr-Df-cetuximab- 800CW, ex vivo BLI/PET/NIRF imaging, and histology all confirmed CD 105 specificity of the tracer. NIRF imaging-guided removal of 4T1 tumors with Df-TRC105-800CW in a subcutaneous model was also straightforward.

CONCLUSIONS

We report the first PET/NIRF imaging of CD105 expression in a MBC model. Broad clinical potential of TRC105- based agents was shown in many tumor types, which also enabled early detection of small metastases and provided intraoperative guidance for tumor removal.

MR imaging assessment of lumbar intervertebral disk degeneration and age-related changes: apparent diffusion coefficient versus T2 quantitation

BACKGROUND AND PURPOSE

T2 and ADC mappings are 2 quantitative MR imaging tools for assessing IVDD. This study aimed to compare these 2 measures in detecting IVDD and its age-related changes.

MATERIALS AND METHODS

Thirty-seven asymptomatic volunteers and 28 patients with back pain or sciatica were examined, and their lumbar disk T2 and ADC maps were quantified via sagittal imaging protocols at 1.5T. For all participants, the Pfirrmann system was used by 2 radiologists for grading disks. T2 and ADC values in the inner portion of disks were measured, and their variances in different grades were analyzed by 1-way ANOVA testing. The ability of T2 and ADC measures to differentiate IVDD grades was compared on the basis of their ROC curves. For asymptomatic subjects, the correlations between age and the 2 MR imaging measures were assessed by the Pearson correlation test.

RESULTS

Both T2 and ADC values were found to decrease with the increasing Pfirrmann grades except T2 in grade V. Significant T2 differences were seen among grades I-IV, but not between grades IV and V. There were no significant ADC differences among grades I-III. Moreover, the areas under the ROC curves differed significantly (0.95 and 0.67 for T2 and ADC, respectively). Linear regression analysis revealed that T2 yielded more significant correlation with age (r = -0.77) than ADC did (r = -0.37).

CONCLUSIONS

T2 quantitation provides a more sensitive and robust approach for detecting and characterizing the early stage of IVDD and age-related disk changes.

Examination of the hdrRM regulon yields insight into the competence system of Streptococcus mutans

Previous studies have identified the hdrRM operon as a novel regulatory system induced by conditions of high cell density. Little is known about the genes under the control of this system, but a variety of important phenotypes are associated with either hdrR overexpression or mutation of hdrM. To characterize the regulatory function of the HdrRM system in Streptococcus mutans we used a microarray approach to compare the transcriptional profiles of an hdrR overexpression strain with an hdrM mutant. Both strains exhibited almost identical profiles, which included all of the known late competence genes as well as a variety of competence-induced bacteriocins. Through a combination of real-time reverse transcription-polymerase chain reaction (PCR), reporter gene analysis and random amplification of complementary DNA ends PCR, we confirmed the role of comX as a central intermediate regulator of numerous genes in the hdrRM regulon. Through these studies, we also identified novel comX-regulated genes required for natural competence. Taken together, our results suggest that the primary function of the HdrRM system is to regulate the late competence genes together with various bacteriocins. This occurs independently of the ComCDE system, even though both systems regulate nearly identical genes. This suggests that S. mutans has multiple parallel input sensory systems that control the same output response: the induction of natural competence and concurrent production of bacteriocins.

BRSK2 expression as a prognosis marker in pancreatic cancer patients

e15603

Background: The prognosis of pancreatic cancer remains dismal because of difficult early diagnosis, low resection rate and aggressive biological behavior. The research of factors related to oncogenesis, tumor infiltration and metastasis is valuable. AMPK(AMP-activated protein kinase)family is a group of regulators on the cellular energy metabolism which are sensitive to the cytoplasmic change of AMP/ATP ratio. As a member of AMPK, BRSK2 is found to be expressed in human pancreatic cell line and facilitate the tumor cell survival on glucose starving. In order to examine the expression of BRSK2 in human pancreatic cancer and explore the underline clinical implication, human pancreatic tissue was examined immunohistochemically Correlation of tumor biological behavior, prognosis and BRSK2 expression was examined. Methods: Seventy nine resected tumor specimens were collected. Immunochemical staining method was used to examine the expression pattern of BRSK2 translated protein. Semi-quantitative analysis was employed to compare the expression intensity and content of BRSK2 in tumor issues, peri-tumorous tissue and normal pancreatic tissue. Possible relationship of tumors differentiation, TNM stage, presence or absence of vessel and neural infiltration were explored with BRSK2 expression. The correlation of BRSK2 expression profile and patients survival was explored. Results: BRSK2 was weakly expressed in normal pancreatic tissues and peri-tumor tissues, including the islet and minor ducts. BRSK2 was strongly expressed in pancreatic cancer tissues, the expression intensity was correlated with extent of lymphatic metastasis, distant metastasis, TNM staging and neural invasion. Tumors with lymphatic metastasis, distant metastasis, neural invasion and later TNM stages showed stronger expression of BRSK2. The expression of BRSK2 in pancreatic cancer was closely correlated to the prognosis of patients, those with higher expression pattern showed bad prognosis. Conclusions: BRSK2 is up-regulated in pancreatic cancer; the expression of BRSK2 is correlated with tumor biological behavior and patient's prognosis.

No significant financial relationships to disclose.

Unscheduled apoptosis during acute inflammatory lung injury

Apoptosis is a mode of cell death currently thought to occur in the absence of inflammation. In contrast, inflammation follows unscheduled events such as acute tissue injury which results in necrosis, not apoptosis. We examined the relevance of this paradigm in three distinct models of acute lung injury; hyperoxia, oleic acid, and bacterial pneumonia. In every case, it was found that apoptosis is actually a prominent component of the acute and inflammatory phase of injury. Moreover, using strains of mice that are differentially sensitive to hyperoxic lung injury we observed that the percent of apoptotic cells was well correlated with the severity of lung injury. These observations suggest that apoptosis may be one of the biological consequences during acute injury and the failure to remove these apoptotic cells may also contribute to the inflammatory response.

[The black diaphragm intraocular lens implantation]

OBJECTIVE

To evaluate the clinical effect of the black diaphragm intraocular lens (IOL) implantation.

METHODS

The black diaphragm IOL implantation performed on 23 cases (23 eyes) of traumatic aniridia (21 eyes) and congenital aniridia (2 eyes) was studied retrospectively.

RESULTS

Photophobia was reduced obviously and the naked visual acuity was improved in all 23 cases after the black diaphragm IOL implantation, VA > or = 0.1 in 16 cases (70%). The complications included vitreous hemorrhage (2 eyes) in the operation, and there were exudates on the surface of IOL (13 eyes), IOP elevation (3 eyes), macular hole (1 eye), recurrent retinal detachment (1 eye) and corneal decompensation (5 eyes) after the operation.

CONCLUSION

The black diaphragm IOL implantation provides an effective means of treating traumatic or congenital aniridia, but the indication should be strictly controlled.

Microwave-assisted extraction of tanshinones from Salvia miltiorrhiza bunge with analysis by high-performance liquid chromatography

A novel microwave-assisted extraction (MAE) method has been developed for the extraction and determination of tanshinones (tanshinone IIA, cryptotanshinone and tanshinone I) from the root of Salvia miltiorrhiza bunge with analysis by HPLC. Various experimental conditions were investigated to optimize the percentage extraction. Under appropriate MAE conditions, such as ethanol concentrations of 95% (v/v), MAE for 2 min, liquid/solid ratio of 10:1 (ml/g), the percentage extraction can reach high in a short time. The percentage extraction (tanshinone IIA: 0.29%; cryptotanshinone: 0.23%; tanshinone I: 0.11%) by MAE was the same or even higher than conventional extraction methods. MAE only needs 2 min, but extraction at room temperature, heat reflux extraction, ultrasonic extraction and Soxhlet extraction need 24 h, 45 min, 75 min and 90 min, respectively. MAE was also available in pilot plant form for larger scale extraction.

Microwave-enhanced dehydration and solvent washing purification of penicillin G sulfoxide

In the present study, a new microwave-enhanced dehydration and solvent washing purification of penicillin G sulfoxide technique has been developed. The results show that microwave irradiation can dehydrate penicillin G sulfoxide from a water content of 14-26 to below 0.5% in 40-60 min in N2 or air. After washing with ethyl acetate to remove impurities and residual water, the penicillin G sulfoxide can be used to synthesize cephalosporanic acid. The recovery of cephalosporanic acid was equal to and the purity of cephalosporanic acid was higher by 2% than that of the current dehydration technique. FTIR spectroscopy was used to study the process of microwave-enhanced dehydration and solvent washing purification of penicillin G sulfoxide.

Constitutive activation of Stat3 by the Src and JAK tyrosine kinases participates in growth regulation of human breast carcinoma cells

Constitutive activation of signal transducer and activator of transcription (STAT) proteins has been detected in a wide variety of human primary tumor specimens and tumor cell lines including blood malignancies, head and neck cancer, and breast cancer. We have previously demonstrated a high frequency of Stat3 DNA-binding activity that is constitutively-induced by an unknown mechanism in human breast cancer cell lines possessing elevated EGF receptor (EGF-R) and c-Src kinase activities. Using tyrosine kinase selective inhibitors, we show here that Src and JAK family tyrosine kinases cooperate to mediate constitutive Stat3 activation in the absence of EGF stimulation in model human breast cancer cell lines. Inhibition of Src or JAKs results in dose-dependent suppression of Stat3 DNA-binding activity, which is accompanied by growth inhibition and induction of programmed cell death. In addition, transfection of a dominant-negative form of Stat3 leads to growth inhibition involving apoptosis of breast cancer cells. These results indicate that the biological effects of the Src and JAK tyrosine kinase inhibitors are at least partially mediated by blocking Stat3 signaling. While EGF-R kinase activity is not required for constitutive Stat3 activation in breast cancer cells, EGF stimulation further increases STAT DNA-binding activity, consistent with an important role for EGF-R in STAT signaling and malignant progression. Analysis of primary breast tumor specimens from patients with advanced disease revealed that the majority exhibit elevated STAT DNA-binding activity compared to adjacent non-tumor tissues. Our findings, taken together, suggest that tyrosine kinases transduce signals through Stat3 protein that contribute to the growth and survival of human breast cancer cells in culture and potentially in vivo.

Overexpression of a dominant-negative signal transducer and activator of transcription 3 variant in tumor cells leads to production of soluble factors that induce apoptosis and cell cycle arrest

Gene therapy of B16 tumors with a dominant-negative signal transducer and activator of transcription (Stat3) variant, designated Stat3beta, results in inhibition of tumor growth and tumor regression. Although only 10-15% of the tumor cells are transfected in vivo, the Stat3beta-induced antitumor effect is associated with massive apoptosis of B16 tumor cells, indicative of a potent bystander effect. Here, we provide evidence that blocking Stat3 signaling in B16 cells results in release of soluble factors that are capable of inducing apoptosis and cell cycle arrest of nontransfected B16 cells. RNase protection assays using multi-template probes specific for key physiological regulators of apoptosis reveal that overexpression of Stat3beta in B16 tumor cells induces the expression of the apoptotic effector, tumor necrosis factor-related apoptosis-inducing ligand. These in vitro results suggest that the observed in vivo bystander effect leading to tumor cell growth inhibition is mediated, at least in part, by soluble factors produced as a result of overexpression of Stat3beta in tumor cells.

Bing de ling, a Chinese herbal formula, stimulates multifaceted immunologic responses in mice

Bing de ling is a Chinese herbal formula most commonly used in complementary medical settings against viral disorders. We have found that bing de ling potentiates upregulation of immune activity when administered to mice in dosages proportional to those used clinically. These mice demonstrated significant elevation of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) production in splenocytes and enhancement of macrophage, natural killer cell, and lymphokine-activated killer cell cytotoxicity. These data are consistent with bing de ling's clinically observed efficacy against viruses and identify the formula as a promising candidate for clinical trials against diverse diseases that may respond to increased immunologic activity.

Gene therapy with dominant-negative Stat3 suppresses growth of the murine melanoma B16 tumor in vivo

Whereas signal transducers and activators of transcription were originally discovered as mediators of normal cytokine signaling, constitutive activation of certain signal transducer and activator of transcription proteins, including Stat3, has been found in increasing numbers of human cancers. Recently, a causal role for Stat3 activation in oncogenesis has been demonstrated, suggesting that Stat3 represents a novel target for cancer therapy. We report here that in vitro expression of a Stat3 variant with dominant-negative properties, Stat3beta, induced cell death in murine B16 melanoma cells that harbored activated Stat3. By contrast, expression of Stat3beta had no effect on normal fibroblasts or the Stat3-negative murine tumor MethA, suggesting that only tumor cells with activated Stat3 have become dependent on this pathway for survival. Significantly, gene therapy by electroinjection of the Stat3beta expression vector into preexisting B16 tumors caused inhibition of tumor growth as well as tumor regression. This Stat3beta-induced antitumor effect is associated with apoptosis of the B16 tumor cells in vivo. These findings demonstrate for the first time that interfering with Stat3 signaling induces potent antitumor activity in vivo and thus identify Stat3 as a potential molecular target for therapy of human cancers harboring activated Stat3.

[The suppressing effect of TIMP-3 gene transfection on the invasion and metastasis of human lung carcinoma cells line]

OBJECTIVE

The purpose of this study is to determine if increasing levels of tissue inhibitor of metalloproteinase 3 (TIMP-3) expression could suppress the malignant phenotype of human cancer cells.

METHODS

The recombinant expression vector, which contains full length cDNA of human TIMP-3, was constructed and transfected into BE1 cell line by lipofectin technique. The invasive and spontaneous metastatic potential was examined.

RESULTS

TIMP-3 mRNA expression in TIMP-3 gene transfected BE1 cells was upregulated as detected by Northern blot. The invasion of TIMP-3 gene-transfected cells across matrigel-coated filters was significantly decreased when compared with controls. Following subcutaneous injection into nude mice, the TIMP-3 transfected cells suppressed primary tumor growth, as characterized by reduced tumor incidence (9/12 vs 6/6), longer latency and reduced metastatic potential to the lungs (1/12 vs 5/6) and lymph nodes (5/12 vs 6/6).

CONCLUSION

The results suggest that upregulation of TIMP-3 expression in BE1 cells resulted in suppression of the invasive potential of BE1 cells in vitro as well as tumorigenic and metastatic potential in nude mice.

[Effect of B16 cells transfected with IL-2 gene on mouse immunity]

IL-2 was introduced into mice B16 melanoma cell line by using retrovirus infection method. Both B16 and B16-IL-2 cells were treated with Mit C beforehand and were then inoculated intraperitoneally as vaccines in mice respectively. Hanks solution was used instead of the vaccine in the control group. The data showed that the tumor incidence rate was zero in the group receiving B16-IL-2 vaccine followed by B16 inoculation. However, incidence rate was 100% in both the B16 vaccine immunization group and in the control groups. Experiments also indicated that the proliferation of splenic lymphocytes induced by MLTR, the specific cytotoxicity of CTL against B16 cells, the activities of splenic NK, LAK, and the level of IL-2 secretion in mice immunized by B16-IL-2 were much higher than those in the mice immunized only with B16 cells as well as the controls. These data indicated that secretion of IL-2 in mice promoted specific and nonspecific anti-tumor immunity of mice. The theoretic basis was provided for IL-2-secreting tumor vaccine.