Evaluation of renal function in chronic kidney disease (CKD) by mDIXON-Quant and Amide Proton Transfer weighted (APTw) imaging.

BACKGROUND: Chronic kidney disease (CKD) is a long-term condition that affects >10% of the adult population worldwide. Noninvasive assessment of renal function has important clinical significance for disease diagnosis and prognosis evaluation. OBJECTIVE: To explore the value of mDIXON-Quant combined with amide proton transfer weighted (APTw) imaging for accessing renal function in chronic kidney disease (CKD). MATERIALS AND METHODS: Twenty-two healthy volunteers (HVs) and 30 CKD patients were included in this study, and the CKD patients were divided into the mild CKD (mCKD) group (14 cases) and moderate-to-severe CKD (msCKD) group (16 cases) according to glomerular filtration rate (eGFR). The cortex APT (cAPT), medulla APT (mAPT), cortex R2⁎ (cR2⁎), medulla R2⁎ (mR2⁎), cortex FF (cFF) and medulla FF (mFF) values of the right renal were independently measured by two radiologists. Intra-group correlation coefficient (ICC) test was used to test the inter-observer consistency. The analysis of variance (ANOVA) was used to compare the difference among three groups. Mann-Whitney U test was used to analyze the differences of R2⁎, FF and APT values among the patient and HV groups. Area under the receiver operating characteristic (ROC) curve (AUC) was used to analyze the diagnostic efficiency. The corresponding threshold, sensitivity, and specificity were obtained according to the maximum approximate index. The combined diagnostic efficacy of R2⁎, FF, and APT values was analyzed by binary Logistic regression, and the AUC of combined diagnosis was compared with the AUC of the single parameter by the Delong test. RESULTS: The cAPT value of the HV, mCKD and msCKD groups increased gradually. The mAPT value and cR2⁎ values of the mCKD and msCKD groups were higher than those of the HV group, while the mFF value of the mCKD group was lower than HV group (all P < 0.05). The cAPT and mAPT values showed good diagnostic efficacy in evaluating different degrees of renal damage, while cR2⁎ and mFF values showed moderate diagnostic efficacy. When combining the APT, R2⁎, and FF values, the diagnostic efficiency was significantly improved. CONCLUSION: mDIXON-Quant combined APTw imaging can be used for improved diagnosis of CKD.

[Clinical study on the relationship between the exosomes in bronchoalveolar lavage fluid and plasma and the severity of lung injury and outcome in early acute respiratory distress syndrome patients].

Objective: To investigate the relationship between the levels of exosomes in bronchoalveolar lavage fluid (BALF) and plasma and the severity of lung injury and its outcome in patients with acute respiratory distress syndrome (ARDS). Methods: Patients who were admitted to the Department of Critical Care Medicine, Zhongda Hospital Affiliated to Southeast University and received invasive mechanical ventilation were selected from August 2020 to April 2021, and they were divided into ARDS group and non-ARDS group. Finally, 33 ARDS patients were included, including 18 males and 15 females, aged (65.5±15.5) years; 10 non-ARDS patients, 8 males and 2 females, aged (57.2±15.3) years. The BALF and plasma of the two groups of patients were collected within 24 hours after enrollment, and the total exosomes of the samples were collected by ultracentrifugation. Nanoparticle tracking analysis (NTA) was used to detect and compare the differences in exosome content between the two groups. Correlation of content with the severity and prognosis of lung injury in ARDS patients. Results: There was no significant difference in gender and age between ARDS group and non-ARDS group (both P>0.05). The exosome in plasma of ARDS group was significantly higher than that of non-ARDS group [(25.3±1.2)/ml vs (24.2±1.6)/ml, P=0.031], while the exosomes in BALF of ARDS group was also higher than that of non-ARDS group [(26.5±1.6)/ml vs (24.6±1.1)/ml, P=0.001]. The exosomes in BALF of patients with ARDS caused by intrapulmonary causes was higher than that in ARDS group caused by extrapulmonary causes [(26.9±1.5)/ml vs (25.2±0.9)/ml, P=0.01], and the infection caused by bacterial shows that the highest exosome level in BALF. The exosomes in the BALF of the mild ARDS group was significantly lower than that of the severe ARDS group [(25.7±1.3)/ml vs (27.2±1.5)/ml, P=0.038]; the exosomes in BALF of ARDS patients was negatively correlated with P/F ratio (r=-0.38, P=0.03); and it was positively correlated with Murray lung injury score (r=0.47, P=0.01). However, the static compliance levels, length of hospital stay, duration of mechanical ventilation, and 28-day outcome were not associated with the exosomes in BALF. Conclusion: Compared with non-ARDS patients, ARDS patients have significantly higher levels of exosomes in BALF and plasma, there is a certain correlation between exosomes derived from BALF and the severity of lung injury in ARDS.

[Effect of convection enhanced delivery on the microstructure of brain extracellular space in aged rats].

OBJECTIVE: To compare the changes of extracellular space (ECS) structure and local drug distribution in adult brain and aged brain at different drug delivery rates in minimally invasive treatment of encephalopathy by convection enhanced delivery (CED) via ECS pathway. METHODS: Thirty-six SD male rats were divided into adult rats group (2-8 months, n=18) and aged rats group (18-24 months, n=18) according to the age of the month. According to the drug rates (0.1 µL/min, 0.2 µL/min, and 0.3 µL/min), they were randomly divided into 3 subgroups, 6 in each subgroup. Gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA) with a concentration of 10 mmol/L were introduced into the caudate nucleus of each group of rats by stereotactic injection. Tracer-based magnetic resonance imaging (MRI) was used to dynamically monitor the diffusion and distribution images of the Gd-DTPA in the brain interstitial system (ISS). Using the self-developed MRI image measurement and analysis system software to process and analyze the obtained images, the diffusion coefficient, clearance rate, volume fraction, and half-life of each group of rats in the caudate nucleus ECS could be acquired. The effects and differences of drug clearance and ECS structural function in the brain of aged rats and adult rats were compared and analyzed at different drug delivery rates. Magnetic tracer DECS-mapping technique was used to observe the distribution and drainage of tracer in caudate nucleus. RESULTS: At the injection rate of 0.1 µL/min, the volume fraction in the aged rats was increased compared with that in the adult rats (18.20%±0.04% vs. 17.20%±0.03%, t=3.752, P=0.004), and the degree of tortuosity was decreased (1.63±0.04 vs. 1.78±0.09, t=-3.680, P=0.004), the drug clearance rate was decreased [(1.94±0.68) mm2/s vs. (3.25±0.43) mm2/s, t=-3.971, P=0.003], and the molecular diffusion in ECS was increased [(3.99±0.21)×10-4 mm2/s vs. (3.36±0.37)×10-4 mm2/s, t=3.663, P=0.004]. When the rate of injection increased to 0.2 µL/min, the drug clearance in ECS of the aged rats was slowed down [(2.53±0.45) mmol/L vs. (3.37±0.72) mmol/L, t=-1.828, P=0.021]. However, there were no significant differences in volume fraction, molecular diffusion in ECS and macroscopic drug metabolism parameters. When the rate of injection increased to 0.3 µL/min, the volume fraction in the aged rats was decreased (17.20%±0.03% vs. 18.20%±0.05%, t=-0.869, P=0.045), and the drug clearance rate in ECS was significantly accelerated [(4.04±0.76) mmol/L vs. (3.26±0.55) mmol/L, t=1.786, P=0.014], and there was no significant difference in tortuosity and the rate of molecular diffusion in the ECS. CONCLUSION: The drug clearance and ECS structural parameters of brain ECS in aged brain with CED administration were changed at different rates, and it has the least effect on ECS in the aged brain at the injection rate of 0.2 µL/min. For the application of CED for the treatment of encephalopathy, we should consider the influence of factors such as age and injection rate, and provide reference for the development of individualized clinical treatment plan for minimally invasive treatment of encephalopathy via ECS pathway.

[Pathogen spectrum in enteroviral infections among children in Beijing from 2010 to 2016].

Objective: To understand the epidemiological and etiological characteristics of enterovirus (EV)-associated diseases among children in Beijing from 2010 to 2016. Methods: This was a repeated cross-sectional study. The throat swabs were collected from children with probable EV-associated diseases at the Children' s Hospital Affiliated to Capital Institute of Pediatrics from 2010 to 2016. The samples were sent for pan-EV, enterovirus 71 (EV-A71) and coxsackievirus A16 (CV-A16) detection by real-time fluorescence reverse transcription polymerase chain reaction (RT-PCR) . The viral types of non-EV-A71 and non-CV-A16 EV-positive samples were identified using modified RT-PCR and sequencing with CV-A6, EV-A/B group and 5 'UTR universal primers. The constituent ratios of the prevalence of different EV types in different age and gender groups were compared. Results: Of the 2 703 throat swabs, 1 992 (73.7%) samples were positive for EV, including EV-A71 (19.1%, 516/2 703), CV-A16 (24.3%, 658/2 703), CV-A6 (22.2%, 600/2 703), CV-A10 (4.5%, 122/2 703) and other types of EV (3.5%, 95/2 703). There was 1 case of EV-A71 and CV-A16 co-infection. The positive detection rate of EV-A group (excluding EV-A71, CV-A16, CV-A6 and CV-A10) increased from 11.3% (7/62) to 95.2% (59/62) after using the modified VP1-specific primers and PCR amplification conditions. During the period between 2010 and 2012, CV-A16 and EV-A71 predominated in EV-positive samples. However, CV-A6 accounted for 60.7% (68/112) in 2013, much higher than CV-A16 (23.2%, 26/112) and EV-A71 (12.5%, 14/112). In 2014, EVs were mainly of CV-A16 and EV-A71, but CV-A6 was the predominant type in 2015 (68.2%, 232/340) and in 2016 (38.6%, 151/391). The epidemic season of EVs was mostly from April to August, but CV-A6 showed a small epidemic peak from October to November. The male-to-female ratio of EV-positive patients was 1.50∶1, and EV-associated diseases mostly occurred in children under 5 years of age. Younger children were more susceptible to CV-A6 than to EV-A71 and CV-A16. Conclusions: From 2010 to 2016, there was a significant change in the spectrum of EVs in children with EV-associated diseases in Beijing. Since 2013, non-EV-A71 and non-CV-A16 increased, and CV-A6 gradually became one of the major pathogens of EV-associated diseases. The modified PCR primers and amplification conditions can effectively improve the reliability of test results.

[Spatial autocorrelation analysis of measles in China, 2005-2014].

OBJECTIVE: To detect the spatial features of measles in China by means of spatial statistical analysis. METHODS: Data of prefecture-level measles cases and incidence from 2005 to 2014 were collected from the China Information System for Disease Control and Prevention. Information collected from the system included demographic characteristics, spatial distribution information, and diagnostic reports. Cases of unconfirmed measles and those with unknown address were ruled out. Cases from Hong Kong, Macao, Taiwan, and foreign countries were not included in this study. Maps were obtained from geographical boundary data at prefecture level from the Chinese Center for Disease Control and Prevention and demographic data from the National Bureau of Statistics. Based on different measures of measles elimination, we divided the data from 2005 to 2014 into three stages: stage 1 (2005-2008), stage 2 (2009-2012), and stage 3 (2013-2014). ArcGIS software was used to describe the spatial distribution and for global and local spatial autocorrelation analysis. RESULTS: The total number of confirmed measles cases reported in the system was 650 222, with average incidence 0.46/100 000. The highest reported incidence was in 2008 (9.95/100 000) and the lowest in 2012 (0.46/100 000). Average incidences for stages 1, 2, and 3 were 8.87/100 000, 1.99/100 000 and 2.96/100 000, respectively. Global Moran's I coefficients from 2005 to 2014 were 0.31, 0.08, 0.36, 0.56, 0.26, 0.48, 0.34, 0.20, 0.29 and 0.52, respectively; all were significant (P<0.05). Average incidences for high-high (H-H) clusters in 2005-2008, 2009-2012, and 2013-2014 were 33.02/100 000, 7.06/100 000, 11.91/100 000, respectively. Western China had high-value clustering consistently throughout all three periods; however, the number of prefectures covered by high-value clusters and discrepancy in the incidence between western and eastern regions were low. Northeast and northern China had H-H clustering in stages 2 and 3. CONCLUSION: In this study, measles incidence was spatially autocorrelated at the prefecture level from 2005 to 2014. Although China has made great progress in the elimination of measles, H-H clusters were consistently present. A need remains in China for targeted measles prevention and control measures.

[Value of R2(*) in evaluating the biological behavior of primary hepatocellular carcinoma].

OBJECTIVE: To investigate the correlation between R2(*) value of enhanced T2 star-weighted angiography (ESWAN) sequence and primary hepatocellular carcinoma infiltration and tumor thrombus, and investigate the biological behavior of HCC. METHODS: A total of 221 cases of patients' imaging data with MRI examination(including ESWAN sequence) diagnosed as primary HCC were retrospectively analyzed.All the patients were collected from January 2014 to September 2015 in the First Affiliated Hospital of Dalian Medical University.The differences of R2(*) values in different MR types of HCC were analyzed.All patients were divided into infiltration group and non-infiltration group, tumor thrombus group and non-tumor thrombus group, the R2(*) values of the paired groups were compared.The diagnostic efficiency of R2(*) in HCC infiltration and tumor thrombus were evaluated by ROC curve, and to find out the threshold values. RESULTS: The MR types of 221 patients included 90 cases of nodular type, 62 cases of massive type, 69 cases of diffuse type.70 patients had tumor thrombus.The R2(*) values of different MR types were (21.82±8.52), (24.17±8.84)and (34.45±11.73) Hz, respectively.There was no statistically significant difference between the nodular and the massive types (P=0.144), while the difference between the nodular and diffuse type, the massive and diffuse types were statistically significant(P=0.000). The R2(*) values of infiltration group and non-infiltration group were (34.45±11.73) and (22.78±8.70) Hz , the R2(*) values of tumor thrombus group and non-tumor thrombus group were (31.20±12.17) and (24.21±9.90) Hz, the difference also had statistically significant(t=7.397 and 4.534, P=0.000 and 0.000). The AUC of R2(*) values for infiltration and tumor thrombus were 0.804, 0.681. R2(*) ≥24.68 Hz was the threshold value to diagnose the infiltration and tumor thrombus. CONCLUSION: R2(*) value can be used as a MR non-enhancement quantitative index to evaluate the biological behavior of HCC.

In vivo protective performance of N95 respirator and surgical facemask.

BACKGROUND: The SARS outbreak in 2003 has spawned a major controversy concerning protective performance facemasks for healthcare workers. This study reports a study on in-vivo protective performance of surgical masks and N95 respirators. METHODS: Typical surgical masks and N95 respirators used in Hong Kong hospitals were tested in comparison with those treated with nano-functional materials (called nano-masks) on various physical properties and in-vivo wear filtration efficiency, as well as usability test in hospitals for surgical masks. RESULTS: Tests on physical properties showed that N95 respirators had significantly lower air permeability and water vapor permeability than surgical masks. The in-vivo filtration tests illustrated that N95 respirators filtered out 97% of potassium chloride (KCl) solution, while surgical masks filtered out 95% of KCl solution. Nano-masks show stronger water repellency and antibacterial activities, but no difference in usability, comparing with normal N95 and surgical masks. CONCLUSIONS: Surgical masks can provide in-vivo filtration protection of 95% filtration efficiency. N95 respirators provide higher in-vivo filtration efficiency of 97% with significant reduction of air permeability and water vapor permeability. Compared to normal surgical masks/respirators, the nano-masks can provide additional protective functions in stopping capillary diffusion and antibacterial activities.

All-optical time-delay relay based on a bacteriorhodopsin film.

Using the property of dynamic complementary suppression modulated transmission of bacteriorhodopsin film, we propose and demonstrate an all-optical time-delay relay in an incoherent light system. The relay can last for a certain amount of time after the switch function of turn off (or turn on) is activated. Furthermore, the delay time can be adjusted by changing the lifetime of the M state and the intensities of blue and yellow beams.

Antimicrobial effect of surgical masks coated with nanoparticles.

This study assessed the antimicrobial activity of nanoparticles (consisting of a mixture of silver nitrate and titanium dioxide) and nanoparticle-coated facemasks to protect against infectious agents. The minimum inhibitory concentrations of the nanoparticles against Escherichia coli and Staphylococcus aureus were 1/128 and 1/512, respectively. The antibacterial activity of nanoparticle-coated masks was quantified according to the procedures of AATCC 100-1999. A 100% reduction in viable E. coli and S. aureus was observed in the coated mask materials after 48 h of incubation. Skin irritation was not observed in any of the volunteers who wore the facemasks. Nanoparticles show promise when applied as a coating to the surface of protective clothing in reducing the risk of transmission of infectious agents.

Photochemistry in dried polymer films incorporating the deionized blue membrane form of bacteriorhodopsin.

The preparation and photochemical properties of dried deionized blue membrane (dIbR600; lambdamax approximately 600 nm, epsilon approximately 54, 760 cm-1 M-1, f approximately 1.1) in polyvinyl alcohol films are studied. Reversible photoconversion from dIbR600 to the pink membrane (dIbR485; lambdamax approximately 485 nm) is shown to occur in these films under conditions of strong 647-nm laser irradiation. The pink membrane analog, dIbR485, has a molar extinction coefficient of approximately 39,000 cm-1 M-1 (f approximately 1.2). The ratio of pink --> blue and blue --> pink quantum efficiencies is 33 +/- 5. We observe an additional blue-shifted species (dIbR455, lambdamax approximately 455 nm) with a very low oscillator strength (f approximately 0.6, epsilon approximately 26,000 cm-1 M-1). This species is the product of fast thermal decay of dIbR485. Molecular modeling indicates that charge/charge and charge/dipole interactions introduced by the protonation of ASP85 are responsible for lowering the excited-state all-trans --> 9-cis barrier to approximately 6 kcal mol-1 while increasing the corresponding all-trans --> 13-cis barrier to approximately 4 kcal mol-1. Photochemical formation of both 9-cis and 13-cis photoproducts are now competitive, as is observed experimentally. We suggest that dIbR455 may be a 9-cis, 10-s-distorted species that partially divides the chromophore into two localized conjugated segments with a concomitant blue shift and decreased oscillator strength of the lambdamax absorption band.

Test and analysis of an electro-optic dynamic diverging lens for three-dimensional optical memories.

We present the experimental results of a two-dimensional electro-optic dynamic diverging lens for dynamic imaging. The device is based on a lanthanum-modified lead zirconate titanate ceramic wafer. It produces a smooth phase-modulation distribution, which almost eliminates the diffraction loss of interdigital electrodes and the interference among different diffraction orders that exist in most of these types of devices. The continual change of focal length in this device is achieved by an applied control voltage. A dynamic-imaging system is demonstrated. It can be used to address three-dimensional optical memories. The aberration of the device as compared with an ideal lens is also numerically evaluated. With minor modification to the applied voltage distribution on the device, its performance is comparable with that of an ideal lens.

Lanthanum-modified lead zirconate titanate ceramic wafer-based electro-optic dynamic diverging lens.

We present a lanthanum-modified lead zirconate titanate (PLZT) ceramic wafer-based electro-optic dynamic diverging lens. A quadratic refractive-index modulation is induced by application of a linearly changing electrical field inside a f lat PLZT wafer. The design offers a simple and compact structure that produces a smooth phase modulation distribution. A fabricated dynamic lens of 2 mm x 2 mm demonstrates a continuous variable focal length from infinity with no applied voltage to negative 0.77 m with a voltage of 400 V.

Effective photochromic nonlinearity of dried blue-membrane bacteriorhodopsin films.

We report the effective nonlinearity for photochromic conversion in a blue-membrane bacteriorhodopsin film hosted in a dry polyvinyl alcohol matrix. The shift in absorption maximum on photoconversion in this film is larger than that of the same material in hydrated form, thus offering a larger modulation of the refractive index. The photoexcited index modulation is stable for several months, which provides for holographic data recording and long-term photochromic data storage. The effective index modulation is experimentally measured and is in good agreement with the theoretical predictions based on the Kramers-Kronig transformation.

Electro-optic beam-steering device based on a lanthanum-modified lead zirconate titanate ceramic wafer.

We demonstrate a lanthanum-modified lead zirconate titanate ceramic-based electro-optic beam-steering device that has a 3 mm × 3 mm working area. A series of resistors were made by evaporation of chromium onto the substrate to produce and control the required voltage distribution among the electrodes. A steering angle of 0.04° was obtained with an applied voltage of 700 V. Design considerations, computer simulations, and experimental results are presented.

High-efficiency electro-optic grating switch with improved performance.

We present a high-diffraction-efficiency electro-optic grating switch based on a lanthanum-modified lead zirconate titanate ceramic wafer. By the employment of narrow contour-shaped metal electrodes instead of the commonly used indium tin oxide interdigital electrodes, this grating has the advantages of a low intrinsic-diffraction loss, high zero-order light on-off ratio, and fast time response. The zero-order light can be turned off with a voltage of 160 V.

Determination of the refractive index of a bacteriorhodopsin film.

The wavelength-dependent refractive index of a bacteriorhodopsin thin film is measured by the use of a modified critical-angle technique. The effect of the host bovine skin gelatin on the refractive index is analyzed. The measured data on the thin film can be useful for system applications. The methods and procedures are generally applicable to any optically absorbing thin films.

Optical limiting by chemically enhanced bacteriorhodopsin films.

The optical limiting properties of a thin film (~150 microm) of chemically enhanced bacteriorhodopsin under cw laser illumination is investigated. The effective nonlinearity n(2) of the film is measured with the z-scan method. Anomalous absorption at different wavelengths as a function of illumination intensity is observed.

Self-defocusing, self-focusing, and speckle in LiNbO(3) and LiNbO(3):Fe crystals.

The characteristics of light-induced scattering in LiNbO(3) and LiNbO(3):Fe crystals are studied. The experimental and theoretical results show that the light-induced scattering for an extraordinary illumination beam consists of self-defocusing, self-focusing, and speckle. They are caused by the light-induced lensing and fluctuation of the refractive index in the crystals.

Polarization sensitivity of birefringent photorefractive holograms and its applications to binary switching.

The effect of polarization sensitivity on the intensity and the resolution of the diffracted beams from a birefringent photorefractive hologram is investigated. In addition, an optical switching technique based on the sensitivity is demonstrated. The method is capable of implementing a large number of 2 x 2 switching channels with only four holograms. The on/off ratio of the switches can easily reach 100:1. This switching methodology is applicable to either synchronous or asynchronous interconnection with a variety of photorefractive materials.