Na原子Rydberg态能级寿命的计算研究

利用一不依赖于实验参数的理论方法计算了钠原子Rydberg态的能级寿命，计算结果很好地符合已有的实验值及其他理论计算值，此计算方法较为严格并且可以弥补实验的不足。     

Lifetime and six-month prevalence of mental disorders in the Munich follow-up study

Summary The Lifetime and 6 month DSM-III prevalence rates of mental disorders from an adult general population sample of former West Germany are reported. The most frequent mental disorders (lifetime) from the Munich Follow-up Study were anxiety disorders (13.87%), followed by substance (13.51%) and affective (12.90%) disorders. Within anxiety disorders, simple and social phobia (8.01%) were the most common, followed by agoraphobia (5.47%) and panic disorder (2.39%). Females had about twice the rates of males for affective (18.68% versus 6.42%), anxiety (18.13% versus 9.07%), and somatization disorders (1.60% versus 0.00%); males had about three times the rates of substance disorders (21.23% versus 6.11%) of females. Being widowed and separated/divorced was associated with high rates of major depression. Most disordered subjects had at least two diagnoses (69%). The most frequent comorbidity pattern was anxietyand affective disorders. Simple and social phobia began mostly in childhood or early adolescence, whereas agoraphobia and panic disorder had a later average age of onset. The majority of the cases with both anxiety and depression had depression clearly after the occurrence of anxiety. The DIS-DSM-III findings of our study have been compared with both ICD-9 diagnoses assigned by clinicians independently as well as other epidemiological studies conducted with a comparable methodology.     

Oxygen Tension Imaging in the Mouse Retina

A newly developed microscope-based imaging system was used to measure the oxygen tension (PO₂) inside the retinal and choroidal vessels of mice and to generate in vivo maps of retinal PO₂. These maps were generated from the phosphorescence lifetimes of an injected palladium–porphyrin compound using a frequency-domain measurement. The system was fully calibrated and used to produce retinal PO₂ maps at different inspiratory oxygen fractions. PO₂ rose accordingly and predictably as inspiratory O₂ was stepped from hypoxic to hyperoxic conditions. Important experimental and acquisition parameters necessary for applying phosphorescence lifetime imaging to the mouse eye were investigated, including camera exposure and intensifier gain settings. Because of a need to limit light exposure to the retina, PO₂ map quality as measured by the coefficient of determination was investigated as a function of signal-to-noise and accumulated excitation energy deposition. With the development of this technology for use in mice, the potential for investigating the oxygen dynamics in genetically engineered mouse models of retinal disease, including diabetic retinopathy, glaucoma, and age-related macular degeneration, is advanced. © 2003 Biomedical Engineering Society. PAC2003: 4266Ew, 8763Lk, 8719Dd     

Lifetime alcohol intake and risk of non‐Hodgkin lymphoma: Findings from the Melbourne Collaborative Cohort Study

Cohort studies have reported inconsistent evidence regarding alcohol intake and risk of non‐Hodgkin lymphoma (NHL), mostly based on alcohol intake assessed close to study enrolment. We examined this association using alcohol intake measured from age 20 onwards. We calculated usual alcohol intake for 10‐year periods from age 20 using recalled frequency and quantity of beverage‐specific consumption for 37,990 participants aged 40–69 years from the Melbourne Collaborative Cohort Study. Cox regression was performed to derive hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between alcohol intake (g/day) and NHL risk. After a mean follow‐up of 19.3 years, 538 NHL cases were diagnosed. Approximately 80% of participants were either lifetime abstainers or consumed below 20 g of ethanol/day. All categories of lifetime alcohol intake were associated with about 20% lower incidence of NHL compared with lifetime abstention, but there was no evidence of a trend by amount consumed (HR = 0.97 per 10 g/day increment in intake, 95% CI: 0.92–1.03; p value = 0.3). HRs for beer, wine and spirits were 0.91 (95% CI: 0.83–1.00; p value = 0.05), 1.03 (95% CI: 0.94–1.12; p value = 0.6), and 1.06 (95% CI: 0.83–1.37; p value = 0.6), respectively, per 10 g/day increment in lifetime intake. There were no significant differences in associations between NHL subtypes. In this low‐drinking cohort, we did not detect a dose‐dependent association between lifetime alcohol intake and NHL risk.     

A Dual-Input Neural Network for Online State-of-Charge Estimation of the Lithium-Ion Battery throughout Its Lifetime

Online state-of-charge (SOC) estimation for lithium-ion batteries is one of the most important tasks of the battery management system in ensuring its operation safety and reliability. Due to the advantages of learning the long-term dependencies in between the sequential data, recurrent neural networks (RNNs) have been developed and have shown their superiority over SOC estimation. However, only time-series measurements (e.g., voltage and current) are taken as inputs in these RNNs. Considering that the mapping relationship between the SOC and the time-series measurements evolves along with the battery degradation, there still remains a challenge for RNNs to estimate the SOC accurately throughout the battery’s lifetime. In this paper, a dual-input neural network combining gated recurring unit (GRU) layers and fully connected layers (acronymized as a DIGF network) is developed to overcome the above-mentioned challenge. Its most important characteristic is the adoption of the state of health (SOH) of the battery as the network input, in addition to time-series measurements. According to the experimental data from a batch of LiCoO₂ batteries, it is validated that the proposed DIGF network is capable of providing more accurate SOC estimations throughout the battery’s lifetime compared to the existing RNN counterparts. Moreover, it also shows greater robustness against different initial SOCs, making it more applicable for online SOC estimations in practical situations. Based on these verification results, it is concluded that the proposed DIGF network is feasible for estimating the battery’s SOC accurately throughout the battery’s lifetime against varying initial SOCs.     

Hybrid measurement of respiratory aerosol reveals a dominant coarse fraction resulting from speech that remains airborne for minutes

Accurate measurements of the size and quantity of aerosols generated by various human activities in different environments are required for efficacious mitigation strategies and accurate modeling of respiratory disease transmission. Previous studies of speech droplets, using standard aerosol instrumentation, reported very few particles larger than 5 μm. This starkly contrasts with the abundance of such particles seen in both historical slide deposition measurements and more recent light scattering observations. We have reconciled this discrepancy by developing an alternative experimental approach that addresses complications arising from nucleated condensation. Measurements reveal that a large volume fraction of speech-generated aerosol has diameters in the 5- to 20-μm range, making them sufficiently small to remain airborne for minutes, not hours. This coarse aerosol is too large to penetrate the lower respiratory tract directly, and its relevance to disease transmission is consistent with the vast majority of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections initiating in the upper respiratory tract. Our measurements suggest that in the absence of symptoms such as coughing or sneezing, the importance of speech-generated aerosol in the transmission of respiratory diseases is far greater than generally recognized.

Respiratory tract infections are caused by a wide range of pathogenic organisms (1), including a large array of respiratory viruses, such as influenza virus, rhinovirus, measles virus, respiratory syncytial virus, adenovirus, and most recently, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In all these diseases, person-to-person spread involves respiratory droplets, which originate from the mucus layer that covers the epithelium of the respiratory tract or from oral fluid present in the mouth, mostly as saliva. Thus, characterizing respiratory droplets is essential to understanding respiratory pathogen transmission and will inform effective public health policies to curb infections. Four mechanisms for droplet generation are generally considered: breathing, speaking (singing, laughing, etc.), coughing, and sneezing (2). Considering the well-recognized importance of asymptomatic transmission of SARS-CoV-2 (3), our study focuses on the first two of these mechanisms.As highlighted by Wells (4) and Duguid (2) nearly a century ago, the vast majority of respiratory droplets are smaller than ca. 100-μm diameter and fully dehydrate once entering the atmosphere. These desiccated droplets can remain airborne for minutes to hours before landing on solid surfaces. If generated by a person infected by a respiratory virus, they will contain virions that can remain viable and infectious for many hours (5, 6). Upon inhalation, airborne particles can reach different parts of the respiratory tract depending on their size: coarse aerosols with diameter D ≳ 5 μm (7) deposit in the upper respiratory tract (URT), and fine aerosols with D < 5 μm can penetrate deep into the lower respiratory tract (LRT). Many viral pathogens, including SARS-CoV-2, influenza, rhinovirus, and measles virus, can infect both URT and LRT epithelia (1, 8, 9), with URT infections typically associated with mild initial symptoms and LRT infections possibly resulting in life-threatening pneumonia (1, 10–13). Direct infection of the LRT, before the adaptive immune system has been triggered by vaccination or a preceding URT infection, presents a greater risk.An URT infection also can expand into the LRT through microaspiration of oropharyngeal fluids (14, 15). The extent to which inhalation of self-generated URT cough, speech, or sneeze aerosols may contribute to this migration remains unknown. However, it has been argued that this pathway could be significant because an infected carrier is invariably at the center of their own speech aerosol cloud, which results in strongly elevated exposure (16). The risk of migration from the URT to the LRT rises with the viral load and the viability of the virus, which peak around and just prior to the onset of symptoms, respectively (17, 18). For the original Wuhan strain of the SARS-CoV-2 virus, the onset of symptoms occurs about 5 days after the initial infection (17, 19), but it occurs somewhat earlier for the more infectious delta and omicron variants (20).To evaluate the risk of LRT infection, it is important to know the size distribution of particles generated by various respiratory activities. For talking, coughing, and sneezing, studies historically relied on slide sampling techniques of increasing sophistication, followed by microscope observation (2, 21, 22). Droplets generated by breathing or vowel sounds are numerous but very small (≲2 μm) and thus more difficult to evaluate with those classical methods. Instead, such small droplets are now commonly quantified by aerosol detection equipment, such as optical particle sizers (OPSs), based on light scattering (22, 23); aerodynamic particle sizers (APSs), based on the time-of-flight measurement in an accelerating flow field (24); and scanning mobility particle sizers that derive a particle’s size from its mobility in an electric field and are best suited for very small sizes (≲1 μm) (25, 26). APS instruments are less efficient at detecting medium-sized liquid particles, and undercounts as high as 75% for 10-μm droplets have been reported (27).There is some confusion in the literature about the hydration state of reported sizes of respiratory aerosol particles, which shrink by a factor of γ upon evaporation of their aqueous content, thus by a factor of γ³ in volume. After full dehydration, a particle’s radius is determined by its amount of nonvolatile matter. Estimates for γ vary substantially: Nicas et al. (28) proposed γ = 2 for breath particles, based on data extracted from breath condensate by Effros et al. (29) that indicated a high fraction (ca. 8% wt/vol) of glycoproteins, presumably mucins. Holmgren et al. (30) reported γ = 2.4 for breath particles when the relative humidity (RH) is reduced from 99.5% in the small airways to 75%. Bagheri et al. (26) observed γ = 4.5 for singing particles in a diffusion dryer or γ = 4 for large saliva droplets observed directly by microscope imaging. Some of those measurements were conducted directly at the mouth opening, observing the hydrated state using light scattering or holographic imaging techniques (26, 31). Clearly, the concentration of pathogens in dehydrated particles scales with γ³ relative to the originating airway lining fluid (ALF) or saliva. However, the high uncertainty in the applicable γ value, which is frequently not even reported, prevents accurate estimates of airborne virus concentrations.Recently, we and others demonstrated that speech particles can be readily observed by simple video recordings of light scattering by these particles (32–35). Such recordings not only present a visually compelling warning to the public but also provide opportunities to monitor particles before, during, and after dehydration. Those light scattering measurements focused on particles larger than a few microns due to technical sensitivity issues. The intensity of scattered light scales with the square of a particle’s diameter, causing a dynamic range problem and rendering it more challenging to observe the smallest particles, especially in the presence of larger particles. Inexpensive, fast consumer cameras typically use 10- to 12-bit analog-to-digital converters (ADCs), thereby limiting dynamic range; while detectors with an increased ADC range are available, their speed is often insufficient for high-speed recording.Here, we aim to evaluate the entire range of speech droplet sizes produced during different breathing and speaking protocols. To do so, we combined video-recorded light scattering and an OPS to evaluate droplets from 0.3 to 100 μm. Our data show a continuous spectrum that lacks previously reported gaps in the size distribution (36). Our measurements confirm that the gravitational settling rate for dehydrated particles larger than 5 μm steeply increases with size, but considering the high numbers, volumes, and airborne lifetimes of those particles, they are likely to be a dominant factor in transmission of disease.     

Open Porosity and Pore Size Distribution of Mesoporous Silica Films Investigated by Positron Annihilation Lifetime Spectroscopy and Ellipsometric Porosimetry

Tunable mesoporous silica films were prepared though a sol-gel process directed by the self-assembly of various triblock copolymers. Positron annihilation γ-ray energy spectroscopy and positron annihilation lifetime spectroscopy (PALS) based on intense pulsed slow positron beams as well as ellipsometric porosimetry (EP) combined with heptane adsorption were utilized to characterize the open porosity/interconnectivity and pore size distribution for the prepared films. The consistency between the open porosities was examined by the variations of orthopositronium (o-Ps) 3γ annihilation fractions and the total adsorbed volumes of heptane. The average pore sizes deduced by PALS from the longest-lived o-Ps lifetimes are in good agreement with those by EP on the basis of the Barrett–Joyner–Halenda model, as indicated by a well fitted line of slope k = 1. The results indicate that the EP combined with heptane adsorption is a useful method with high sensitivity for calibrating the mesopore size in highly interconnected mesoporous films, whereas PALS is a novel, complementary tool for characterizing both closed and open pores in them.     

Dynamic optical imaging of metabolic and NADPH oxidase-derived superoxide in live mouse brain using fluorescence lifetime unmixing

Superoxide is the single-electron reduction product of molecular oxygen generated by mitochondria and the innate immune enzyme complex, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (Nox), and its isoforms. Initially identified as critical to the host defense against infection, superoxide has recently emerged as an important signaling molecule and as a proposed mediator of central nervous system injury in stroke, neurodegenerative conditions, and aging itself. Complete understanding of superoxide in central nervous system disease has been hampered by lack of noninvasive imaging techniques to evaluate this highly reactive, short-lived molecule in vivo. Here we describe a novel optical imaging technique to monitor superoxide real time in intact animals using a fluorescent probe compound and fluorescence lifetime contrast-based unmixing. Specificity for superoxide was confirmed using validated mouse models with enhanced or attenuated brain superoxide production. Application of fluorescence lifetime unmixing removed autofluorescence, further enhanced sensitivity and specificity of the technique, permitted visualization of physiologically relevant levels of superoxide, and allowed superoxide in specific brain regions (e.g., hippocampus) to be mapped. Lifetime contrast-based unmixing permitted disease model-specific and brain region-specific differences in superoxide levels to be observed, suggesting this approach may provide valuable information on the role of mitochondrial and Nox-derived superoxide in both normal function and pathologic conditions in the central nervous system.