Search

Alzheimer's disease (AD) is the most common cognitive disorder in the elderly. Its main clinical manifestations are cognitive decline (C), behavioral and psychological symptoms (B), and a decline in the activities of daily living (A), also known as ABC symptoms. Early identification and evaluation of ABC symptoms are helpful for establishing the accurate diagnosis, comprehensive treatment, and prognosis of AD. To guide Chinese clinical practice for optimization of the comprehensive management of AD, in 2018, The Academy of Cognitive Disorder of China gathered 22 neurologists and gerontologists in China to build a consensus on the comprehensive management of AD. Based on a review of the evidence, the consensus summarizes the pathogenesis, pathological changes, clinical manifestations, evaluation, diagnosis, drug and non-drug treatment, and patient care for AD. Focus group discussion was used to establish a flowchart of comprehensive ABC management for AD patients. The new consensus provides a feasible AD management process for clinicians.

Mars surface composition detector (MarSCoDe) is a scientific instrument suite onboard the Mars rover of the “Tianwen-1” mission, which uses laser-induced breakdown spectroscopy and shortwave infrared spectroscopy to detect the composition of soils and rocks at the surface of Mars. The optical head unit (OHU) is the core hardware of MarSCoDe, containing a Cassegrain telescope and other optical modules for lasers generation and signals transmission. The unit lacks thermal control resources and is located outside the rover’s cabin, which will directly face the Martian surface drastic temperature changes. We introduce the optomechanical designs that realize the lightweight and high thermal stability of the OHU optical system, especially the designs and implementations of the semiopen primary mirror based on silicon carbide and the fully closed optical bench based on carbon fiber-reinforced polymer. Meanwhile, the advantages and difficulties of silicon carbide, long carbon fiber-reinforced silicon carbide composites, and carbon fiber-reinforced polymer materials used for small and compact optomechanical systems are discussed. Subsequently, the environmental adaptability of the telescope system of OHU was studied through analytical and experimental methods, which show that it can achieve the required optical performance over a temperature range of approximately 100°C.

To guarantee a smooth in-orbit space gravitational wave detection for the Taiji mission, a semi-physical simulation test of inter-satellite laser interference is carried out. The semi-physical simulation test consists of three aspects: the establishment of the inter-satellite laser link, interferometry of the inter-satellite ranging, and simulation of the space environment. With the designed specifications for the semi-physical simulation platform, the test results for the inter-satellite laser interference can be obtained. Based on the semi-physical simulation test, the risks of inter-satellite laser interference technology can be mitigated, laying a solid foundation for the successful detection of in-orbit gravitational waves.

China's Tianwen-1 Mars rover carries a laser-induced breakdown spectroscopy (LIBS) payload named MarSCoDe to analyze the mineral and rock composition on Mars. MarSCoDe is expected to experience a wide working temperature range of about 100 °C, which will lead to a spectral shift of up to ∼40 pixels (∼8.13 nm). Even worse, drastic changes in temperature and environment may cause a loss or increase of some spectral lines of an on-board calibration Ti target. An elastic particle swarm optimization (PSO) approach is proposed to fulfill the on-board spectral calibration of MarSCoDe under this harsh condition. Through establishing a standard wavelength set (SWS) and an individual particle wavelength set (PWS), and further elastically selecting a part of PWS to compare with SWS, the problem of spectral shift and number mismatch can be solved gradually with the evolution of the particle swarm. Some tests of standard lamps and Ti with MarSCoDe, placed in a Mars simulation environment chamber (MSEC) in a temperature range of 70 °C, were completed. Compared with the standard spectrum of the Ti target (obtained at 20 °C), the spectral shifts of the first, second, and third channels are approximately 0.33 nm (5 pixels), 0.85 nm (6.4 pixels), and 8.09 nm (39.8 pixels), respectively, at -40 °C before correction; after PSO correction, the spectral shifts are greatly reduced to up to 0.015 nm, and specially for the 626.28 nm line, the spectral shift is reduced from 8.09 nm to about 0 nm. Experimental results demonstrate that the PSO-based approach can not only correct the on-board spectral shift but also solve the number mismatch of spectral lines of MarSCoDe in the harsh working environment of Mars. Further, it can be extended to the on-board calibration of other spectral payloads for deep space exploration.

Background and purpose Significant clinical recovery has commonly been observed in ischaemic stroke patients with irreversible brain structural damage. However, brain mechanisms that help to maintain clinical function remain unclear. Methods Sixty-two patients with acute ischaemic stroke underwent longitudinal clinical assessments and magnetic resonance scanning. The clinical recovery trajectory was evaluated using a hierarchical linear model and intrinsic connectivity was analysed with a seed-based approach to examine its changing pattern based on the regional volume changes calculated using voxel-wise analysis. Results It was observed that clinical outcome measures improved mainly in the short-term period (baseline versus 3 weeks) and then remained stable. Grey matter volume was reduced significantly in the bilateral caudate over the entire 3-year long-term period. Significant intrinsic connectivity increases were observed in the caudate-middle cingulum over the short-term period and in the caudate-precuneus and caudate-calcarine over the long-term period. Finally, it was found that increased caudate-calcarine connectivity was associated with reduced right caudate volume, and a positive correlation was found between increased caudate-middle cingulum connectivity and the amount of modified Rankin score changes. Conclusions The increased intrinsic connectivity found in this study tends to be a compensatory mechanism for post-stroke structural damage, associated with clinical recovery. The study helps in understanding the significance of enhanced intrinsic connectivity in post-stroke long-term assessment and rehabilitation.

Satellite angular micro-vibration has an important impact on the efficiency of space quantum communication links. We measured the micro-vibrations on the Micius satellite in orbit using a high-precision optical sensor mounted on the satellite and analyzed the power spectral density. We designed a compound axis acquisition, tracking, and pointing (ATP) system based on a two-axis turntable and tested its suppressive effect on the micro-vibration through in-orbit experiments. The tracking error caused by the angular micro-vibration was found to be 9.3 µrad, with the energy concentrated primarily in the frequencies below 30 Hz; after suppression by the ATP system, the error was 0.47 µrad.

Background New therapies are urgently needed for Alzheimer’s disease (AD). Sodium oligomannate (GV-971) is a marine-derived oligosaccharide with a novel proposed mechanism of action. The first phase 3 clinical trial of GV-971 has been completed in China. Methods We conducted a phase 3, double-blind, placebo-controlled trial in participants with mild-to-moderate AD to assess GV-971 efficacy and safety. Participants were randomized to placebo or GV-971 (900 mg) for 36 weeks. The primary outcome was the drug-placebo difference in change from baseline on the 12-item cognitive subscale of the Alzheimer’s Disease Assessment Scale (ADAS-cog12). Secondary endpoints were drug-placebo differences on the Clinician’s Interview-Based Impression of Change with caregiver input (CIBIC+), Alzheimer’s Disease Cooperative Study-Activities of Daily Living (ADCS-ADL) scale, and Neuropsychiatric Inventory (NPI). Safety and tolerability were monitored. Results A total of 818 participants were randomized: 408 to GV-971 and 410 to placebo. A significant drug-placebo difference on the ADAS-Cog12 favoring GV-971 was present at each measurement time point, measurable at the week 4 visit and continuing throughout the trial. The difference between the groups in change from baseline was − 2.15 points (95% confidence interval, − 3.07 to − 1.23; p Conclusions GV-971 demonstrated significant efficacy in improving cognition with sustained improvement across all observation periods of a 36-week trial. GV-971 was safe and well-tolerated. Trial registration ClinicalTrials.gov, NCT02293915. Registered on November 19, 2014

Facing considerable challenges associated with aging and dementia, China urgently needs an evidence-based health-care system for prevention and management of dementia. The Beijing Aging Brain Rejuvenation Initiative (BABRI) is a community-based cohort study initiated in 2008 that focuses on asymptomatic stages of dementia, aims to develop community-based prevention strategies for cognitive impairment, and provides a platform for scientific research and clinical trials. Thus far, BABRI has recruited 10,255 participants (aged 50 and over, 60.3% female), 2021 of whom have been followed up at least once at a 2- or 3-year interval. This article presents aims and study design of BABRI; summarizes preliminary behavioral and neuroimaging findings on mild cognitive impairment (MCI) and results of clinical trials on MCI; and discusses issues concerning early prevention in community, MCI diagnosis methods, and applications of database of aging and dementia. BABRI is proposed to build a systematic framework on brain health in old age.

In EUV lithography, the short wavelength and residual mirror surface roughness increase the flare levels across the slit. As a key research point, the flares of different exposure fields are carefully discussed by numerical simulation. To ensure the effectiveness and practicability of our simulations, the test patterns are generated according to the general design rules for 7nm technology node. The NILS, process variation band (PVB) and MEEFs from mask optimizations and source mask optimizations (SMO) results are compared. From the comparisons, the constant flare has a greater influence on NILS and PVB than that on MEEF. In contrast, the flare map caused more reduction on the MEEF values.

Background Approximately 80% of adolescent scoliosis cases are idiopathic, and some non-idiopathic scoliosis cases caused by spinal cord abnormalities are misdiagnosed as idiopathic scoliosis. This study examined the risk factors for non-idiopathic scoliosis with intramedullary abnormalities, explored the feasibility of whole-spine MRI, and provided a theoretical basis for the routine diagnosis and treatment of adolescent idiopathic scoliosis. Method The clinical data of adolescent scoliosis patients who were admitted to Shanghai Tongren Hospital and Shanghai Changhai Hospital between July 1, 2013, and December 31, 2018, were reviewed. According to the whole-spine MRI results, the patients were divided into either the idiopathic group or the intramedullary abnormality group. Sex, age, main curvature angle, main curvature direction, kyphosis angle, scoliosis type, coronal plane balance, sagittal plane balance, abdominal wall reflex, sensory abnormality, ankle clonus and tendon reflexes were compared between the two groups. Student’s t test was used to evaluate the differences in the continuous variables, and the chi-square test was used to evaluate the differences in the categorical variables. Fisher’s exact test was applied to detect the difference in the rate of intraspinal anomalies between the groups. Logistic regression was used to evaluate the correlation between the multivariate risk factors and intramedullary abnormalities. Result A total of 714 adolescent scoliosis patients with a mean age of 13.5 (10–18 years) were included in the study, and intramedullary abnormalities were found in 68 (9.5%) patients. There were statistically significant differences in the incidence rates of intramedullary abnormalities between males and females, left and right thoracic curvatures, angular scoliosis and smooth scoliosis, and abnormal abdominal wall reflex and ankle clonus (P Conclusion Risk factors associated with adolescent scoliosis caused by abnormal intramedullary abnormalities included male sex, thoracic scoliosis on the left side, sharp curvature of the spine, abnormal abdominal wall reflex and ankle clonus. In adolescent scoliosis patients, the incidence of scoliosis caused by intramedullary abnormalities was approximately 9.5%. These clinical indicators suggest that there is a high-risk adolescent scoliosis population who should undergo whole-spinal MRI preoperatively to rule out intramedullary abnormalities.

Anti-Sry-like high mobility group box (SOX) 1 antibodies (abs) are partly characterized onconeural autoantibodies (autoabs) due to their correlation with neoplastic diseases. Anti-SOX1 abs are associated with various clinical manifestations, including Lambert-Eaton myasthenic syndrome (LEMS) and paraneoplastic cerebellar degeneration (PCD). However, the clinical characteristics of patients with anti-SOX1 abs have not been described in detail. This review systematically explores the reported patients with anti-SOX1 abs and analyzes these cases for demographic characteristics, clinical features, coexisting neuronal autoabs, neuroimaging findings, treatment, and clinical outcomes. In addition, considering that PCD is the most common paraneoplastic neurological syndrome and that the association between PCD and anti-SOX1 abs remains unclear, we focus on the presence of autoabs in relation to PCD and associated tumors. PCD-associated autoabs include various intracellular autoabs (e.g., anti-Hu, anti-Yo, anti-Ri, and anti-SOX1) and cell-surface autoabs (anti-P/Q-type voltage-gated calcium channel). Commonly involved tumors in PCD are small-cell lung cancer (SCLC), gynecological, and breast tumors. LEMS is the most common clinical symptom in patients with anti-SOX1 abs, followed by PCD, and multiple neuronal autoabs coexist in 47.1% of these patients. SCLC is still the predominant tumor in patients with anti-SOX1 abs, while non-SCLC is uncommon. No consistent imaging feature is found in patients with anti-SOX1 abs, and there is no consensus on either the therapy choice or therapeutic efficacy. In conclusion, the presence of anti-SOX1 abs alone is a potential predictor of an uncommon paraneoplastic neurological disorder, usually occurring in the setting of LEMS, PCD, and SCLC. The detection of anti-SOX1 abs contributes to an early diagnosis of underlying tumors, given the diversity of clinical symptoms and the absence of characteristic neuroimaging features.

In this paper, a new way, which is based on defocus phase modulation and paraxial ray-tracing theory, is paved for determining laser beam quality dynamically. Theoretical considerations are verified by numerical simulations.

The establishment of a high-precision optical link is a necessary condition for satellite-to-ground quantum communication experiments. Compared with conventional laser communications, a quantum experimental satellite needs to solve special requirements such as the great difference between the energy of quantum light and beacon light, and the establishment of optical links between one satellite and two ground stations. Based on the scientific demands of satellite-to-ground quantum communication, this paper proposes an overall scheme for an optical link establishing system with a combination of satellite pointing and load autonomous searching. By using a multiple-axis pointing control method, the requirements of high-precision optical tracking are met. We use the stare-stare capture method to achieve fast capture between the satellite and the ground stations. The high-precision alignment of the satellite and ground quantum beams is realized by using a method of joint scanning and system correction. Finally, in-orbit test results of the Mo-tse quantum experimental satellite are given. The experimental data show that all parameters in the establishment of optical links meet or exceed the expected requirements.

White matter hyperintensity (WMH) is a common finding in aging population and considered to be a contributor to cognitive decline. Our study aimed to characterize the spatial patterns of WMH in different severities and explore its impact on cognition and brain microstructure in non-demented elderly. Lesions were both qualitatively (Fazekas scale) and quantitatively assessed among 321 community-dwelled individuals with MRI scanning. Voxel- and atlas-based analyses of the whole-brain white matter microstructure were performed. The WMH of the same severities was found to occur uniformly with a specific pattern of lesions. The severity of WMH had a significant negative association with the performance of working and episodic memory, beginning to appear in Fazekas 3 and 4. The white matter tracts presented significant impairments in Fazekas 3, which showed brain-wide changes above Fazekas 4. Lower FA in the superior cerebellar peduncle and left posterior thalamic radiation was mainly associated with episodic memory, and the middle cerebellar peduncle was significantly associated with working memory. These results support that memory is the primary domain to be affected by WMH, and the effect may potentially be influenced by tract-specific WM abnormalities. Fazekas scale 3 might be the critical stage predicting a future decline in cognition.

Deep brain stimulation is a therapy for Alzheimer's disease (AD) that has previously been used for mainly mild to moderate cases. This study provides the first evidence of early alterations in performance induced by stimulation targeted at the fornix in severe AD patients. The performance of the five cases enrolled in this study was scored with specialized assessments including the Mini-Mental State Examination and Clinical Dementia Rating, both before and at an early stage after deep brain stimulation. The burden of caregivers was also evaluated using the Zarit Caregiver Burden Interview. As a whole, the cognitive performance of patients remained stable or improved to varying degrees, and caregiver burden was decreased. Individually, an improved mental state or social performance was observed in three patients, and one of these three patients showed remarkable improvement in long-term memory. The conditions of another patient deteriorated because of inappropriate antipsychotic medications that were administered by his caregivers. Taken together, deep brain stimulation was capable of improving some cognitive aspects in patients with severe AD, and of ameliorating their emotional and social performance, at least at an early stage. However, long-term effects induced by deep brain stimulation in patients with severe AD need to be further validated. More research should focus on clarifying the mechanism of deep brain stimulation. This study was registered with ClinicalTrials.gov (NCT03115814) on April 14, 2017.

We report the polarization preservation of quantum light in the optical systems of the terminals of the world’s first quantum communication satellite, Micius. The main scientific experimental goals and polarization requirements of the satellite and ground station are introduced firstly. Three optical terminals are equipped on Micius to achieve our scientific goals, including a quantum entanglement source (QES), quantum entanglement transmitter (QET) and quantum key distribution transmitter (QKDT), and the function of each optical terminal is described briefly. A polarization-maintaining design for the terminals on Micius is critical for quantum communication, and the optical structure of the QKDT and QET is determined by using three polarization-maintaining methods. The optical configurations of the QKDT and QET are introduced, and the polarization-maintaining methods are described in detail. The final polarization extinction ratios of the QKDT and QET at wavelengths of 850 nm and 810 nm are better than 500:1, which provides critical technical support for realizing the scientific goals of Micius.

To meet the requirement of high-accuracy pointing of quantum signals in satellite-to-ground quantum communication, this paper proposes a flexible satellite-based pointing method that changes the fine tracking point to solve the problem from point-ahead angle and ground beacon laser offset. This method does not require the use of a point-ahead mechanism and can detect the pointing angle in real time. Detailed algorithms and analysis are given. The method has been verified in orbit on the quantum science satellite Micius. The satellite-to-ground test results show that the quantum signal pointing accuracy is between 0.5∼1.0 µrad, which meets the efficiency requirements of satellite-to-ground quantum communication.

Quantum key distribution (QKD) uses individual light quanta in quantum superposition states to guarantee unconditional communication security between distant parties. In practice, the achievable distance for QKD has been limited to a few hundred kilometers, due to the channel loss of fibers or terrestrial free space that exponentially reduced the photon rate. Satellite-based QKD promises to establish a global-scale quantum network by exploiting the negligible photon loss and decoherence in the empty out space. Here, we develop and launch a low-Earth-orbit satellite to implement decoy-state QKD with over kHz key rate from the satellite to ground over a distance up to 1200 km, which is up to 20 orders of magnitudes more efficient than that expected using an optical fiber (with 0.2 dB/km loss) of the same length. The establishment of a reliable and efficient space-to-ground link for faithful quantum state transmission constitutes a key milestone for global-scale quantum networks., Comment: 18 pages, 4 figures

Polarization properties of Gaussian Schell-mode type photon beams propagating through the non-Kolmogorov turbulence in a slant channel are studied which are based on the model of quantum field and the effective photon annihilation/creation operator. Our numerical results show that the degree of polarization increases with the increasing of the transverse coherent width of source ρs0, the source's transverse size ω0 and the power law of the turbulent spectrum, but the degree of polarization P decreases as the zenith angle θ increases. The effect of the wavelength of light beam on the degree of polarization of Gaussian Schell-model beams is small.

Polarization properties of single photon states propagating through the non-Kolmogorov turbulence in a slant channel are studied based on the degree of polarization of quantum field. The degree of polarization of single photon states for linearly polarized quantum beam propagation in a slant turbulent channel are developed. Our results show that the effects of the outer scale fluctuations of atmospheric turbulence and the wavelength difference of the beams on the polarization can be ignored and the smaller inner scale of turbulence and larger zenith angle of communication channel will lead to larger fluctuations of the polarization of single-photon states. The effects of the inner scale of turbulence on polarization of single photon states are more significant for bigger refractive-index power and bigger zenith angles.

The effects of beam wander corrected and pointing errors on the average capacity of a non-Kolmogorov turbulent atmosphere communication channel are studied. The gamma–gamma irradiance probability density function model has been considered to include the effects of non-Kolmogorov turbulence. An expression for the average capacity under beam wander corrected, pointing errors and the spectral index of refractive-index fluctuation. Simulation results for effects of circular detection aperture of radius, atmosphere turbulence strength and wavelength on average capacity are presented. Our results show that the average capacity has an oscillation in the case of short propagation distance, but in the case of long propagation distance, it has gradually reduced curves. And the turbulence strength has a strong influence on average capacity. In general, turbulence reduces the average capacity; it can reduce average capacity by increasing of the power law α. We can ignore the little effects of wavelength increases on the average capacity.

The performance of optical wireless communication links depends strongly on the atmospheric conditions and the parameters of the link such as the propagation distance, the operation wavelength, jitter variance, attenuation coefficient and effective beam spot radius at the receiver. The analytical expression for the evaluation of the average capacity of optical wireless communication systems is derived, using the gamma–gamma distribution in the non-Kolmogorov atmosphere turbulence. The impact of atmospheric attenuation, beam wander and pointing errors on the average of the optical wireless communication link is investigated. It is shown that the capacity has a fluctuation curve, when power law α increases, and the power law α of minimum point in fluctuation curve is bigger as the non-Kolmogorov turbulence strength is stronger.

With Rytov approximation and Kolmogorov spectrum model of index-of-refraction fluctuation, we study the effects of turbulence aberration on the orbital angular momentum of single photons in atmospheric communication channel. A theoretical model of measurement probabilities of orbital angular momentum states for single photons propagation under the Zernike tilt corrected slant path turbulent atmosphere channel is established. Our research shows that tilt-corrected residual aberration not only damage the initial OAM, but also induce new OAM. With the increasing of D / ρ 0 , the number of the initial OAM photons will go down while the effective number of new OAM ascends. Meanwhile, the receiving probability of initial OAM photons declines, as the turbulence shifts from weak to strong. For Zernike tilt-corrected residual aberration, the receiving probability of initial OAM photons declines as the diameter of detector increases. The effect of Zernike tilt-corrected residual aberration on OAM of the photons is more larger than the effect of Zernike tilt turbulent aberration.

The polarization fluctuations of single-photon beam propagation through the slant path turbulent atmosphere are studied. The Stokes operators and the degree of polarization of single-photon beam in a turbulent atmosphere are obtained. It is shown by analytical calculations, that the quantum degree of polarization of linearly polarization light is a decrease function of the atmospheric turbulence strength and the propagation distance for lower detection photon number.

Using Rytov approximation and modified von Karman spectrum model of the index-of-refraction, the detection probability of single-photon beam propagation in a atmospheric turbulence communication channel is investigated and developed. In this research, the single-photon beam is assumed as a pulse beam which has an initial Gaussian temporal shape of the pulse and a Laguerre–Gaussian fundamental-model spatial distribution. It is found that in order to obtain the messages probability greater than or equal 0.1, we should encode and dispatch 66680 photons in identical information carriers at the transmitting side, and the radius of the detector at the receiving plane must be at least up to 0.4 m when the photons propagate in a turbulent atmosphere communication channel.

We analyze the orbital angular momentum (OAM) crosstalk of single photons propagation through low-order atmospheric turbulence. The probability models of the orbital angular momentum crosstalk for single photons propagation in the channel with the non-Kolmogorov turbulence tilt, coma, and astigmatism and defocus aberration have been established. It is found, for α = 11/3, that the turbulent tilt is the dominant aberration which causes the orbital angular momentum crosstalk, the coma is second and the astigmatism is third, but the defocus aberration has no impact on OAM. The results also indicate that the regularities of orbital angular momentum crosstalk caused by the tilt, the coma and the astigmatism are almost the same, respectively. The crosstalk probability of the orbital angular momentum increases as the azimuth mode index p of Laguerre–Gaussian (LG) beam increases, the turbulent strength Cn2 enhances, the orbital angular momentum quantum number rises, the diameter of circular sampling aperture D and the channel zenith angle θ increase.

In order to evaluate the role of positron emission tomography (PET) with N-methyl-[(11)C]-2-(4'-methylaminophenyl)-6-hydroxybenzothiazole, also known as Pittsburgh compound B (PIB), in the early diagnosis of Alzheimer's disease (AD). Clinical data were collected, and PIB PET cerebral imaging was performed in patients with AD (n = 6), mild cognitive impairment (MCI) (n = 7), and elderly, mentally normal controls (NCs) (n = 7). PET images of the subjects were then analyzed. Visual analysis showed that the radioactivity clearance rate in AD patients was significantly different from that found in the NC group. Furthermore, the radioactivity clearance rate 45 min after PIB injection was significantly lower than the NC group. Images from the MCI group presented heterogeneous results, overlapping with those from both the AD and NC groups. Statistical analysis showed that the radioactivity clearance rate during 5-45 min post-injection was significantly lower in the AD group (41-77%) than the control group (75-81%) (P > 0.05) and the MCI group (59-77%). The radioactivity clearance rate in the bilateral parietal lobes, frontal, temporal, and right occipital lobes, and the bilateral corpora striata in MCI group were lower than that in control group (P < 0.05). PIB PET brain imaging can differentiate early AD patients from NCs and may have certain value in identifying patients progressing to MCI.

Image correlation matching is a tracking method that searched a region most approximate to the target template based on the correlation measure between two images. Because there is no need to segment the image, and the computation of this method is little. Image correlation matching is a basic method of target tracking. This paper mainly studies the image matching algorithm of gray scale image, which precision is at sub-pixel level. The matching algorithm used in this paper is SAD (Sum of Absolute Difference) method. This method excels in real-time systems because of its low computation complexity. The SAD method is introduced firstly and the most frequently used sub-pixel fitting algorithms are introduced at the meantime. These fitting algorithms can’t be used in real-time systems because they are too complex. However, target tracking often requires high real-time performance, we put forward a fitting algorithm named paraboloidal fitting algorithm based on the consideration above, this algorithm is simple and realized easily in real-time system. The result of this algorithm is compared with that of surface fitting algorithm through image matching simulation. By comparison, the precision difference between these two algorithms is little, it’s less than 0.01pixel. In order to research the influence of target rotation on precision of image matching, the experiment of camera rotation was carried on. The detector used in the camera is a CMOS detector. It is fixed to an arc pendulum table, take pictures when the camera rotated different angles. Choose a subarea in the original picture as the template, and search the best matching spot using image matching algorithm mentioned above. The result shows that the matching error is bigger when the target rotation angle is larger. It’s an approximate linear relation. Finally, the influence of noise on matching precision was researched. Gaussian noise and pepper and salt noise were added in the image respectively, and the image was processed by mean filter and median filter, then image matching was processed. The result show that when the noise is little, mean filter and median filter can achieve a good result. But when the noise density of salt and pepper noise is bigger than 0.4, or the variance of Gaussian noise is bigger than 0.0015, the result of image matching will be wrong.

Asia is the most populous region in the world and its rapidly growing societies are the sources of global development. However, aging of its population with increasing occurrence of diseases, of which dementia is the most prominent, is a major challenge to healthcare system. For example, there are 177 million people aged 65 and older living with dementia in China, expressing 20% of dementia patients worldwide. It has been estimated that the Chinese proportion of the elderly will reach 30.4% in 2050, which will include 100 million elderly people over 80 years of age [1]. Dementia prevalence in Asia, however, has previously been found to be lower than in Western populations [2]. Cultural differences could contribute to this. Dementia research in Chinese population has been primarily focused on Alzheimer's disease and vascular dementia [2]. Most of our knowledge about dementia, however, comes from studies in Caucasian population. Early and accurate diagnosis of dementia is crucial in order to start with the treatment as early as possible. Intervention and treatment of dementia (AD-dementia) can be cost-effective, but the majority of patients are not diagnosed in a timely manner. Technology is now available that can enable earlier detection of cognitive loss associated with incipient dementia, offering the potential for earlier intervention and health care systems and resulting in a less financial burden to an individual and a society. In this special issue on screening of dementia, we focused on screening tests for the detection of very mild dementia. We have invited a few papers that address those topics accordingly. One paper of this special issue gives a view on dementia screening in an outpatient department of a regional hospital in Taiwan by means of AD8 (ascertainment of dementia 8), a brief informal interview to screen dementia [3]. Screening people at the risk of dementia is a first and a major issue in screening of dementia. Another paper explores depression as a crucial public health issue in Taiwan. By means of brief tool, Epidemiological Studies Depression Scale (CES-D), to screen depression, a ratio of 16.4% of suspected depression patients compared to 13.3% aged patients out of all recruited patients was shown. This result may provide important information for a public health issue. In another paper, by means of AD8 consistent problems with thinking and/or memory were found in 56.8% participants, difficulty in remembering appointments was found in 47% participants, forgetting correct month or year was found in 40.9% of recruited participants in Taiwan, accordingly. Another paper presents the utility of informant AD8 for case finding of cognitive impairment in primary healthcare setting in Singapore. On a sample of 205 patients and their informants, AD8 was shown to be useful for case finding of cognitive impairment in the primary healthcare in one-third of adult patients. Another paper shows efficacy of the Takeda Three Colors Combination (TTCC) test, a screening tool for detection of very mild AD-dementia in Japan. Despite a lower sensitivity, a TTCC test was accomplished within 2 minutes in all subjects, thus being a great potential for the use as an AD screening tool by general practitioners in communities worldwide. Another paper assesses the influence of education on the performance of Chinese version of the Montreal Cognitive Assessment (C-MoCA) compared to Mini-Mental State Examination (MMSE) in detecting amnestic mild cognitive impairment (aMCI) among rural population in Beijing community. C-MoCA showed modest accuracy and was no better than MMSE in detecting aMCI, most likely due to overwhelming effect of education relative to aMCI diagnosis on variations in C-MoCA performance. Finally, all presented cognitive tests show great potential for the use as screening tools for early and very mild dementia worldwide, being easy to apply and at a low cost in communities worldwide. Rajka M. Liscic Gorsev G. Yener Huali Wang Jong-Ling Fuh Jianjun Jia Yuan-Han Yang

Quantum technology establishes a foundation for secure communication via quantum key distribution (QKD). In the last two decades, the rapid development of QKD makes a global quantum communication network feasible. In order to construct this network, it is economical to consider small-sized and low-cost QKD payloads, which can be assembled on satellites with different sizes, such as space stations. Here we report an experimental demonstration of space-to-ground QKD using a small-sized payload, from Tiangong-2 space lab to Nanshan ground station. The 57.9-kg payload integrates a tracking system, a QKD transmitter along with modules for synchronization, and a laser communication transmitter. In the space lab, a 50 MHz vacuum + weak decoy-state optical source is sent through a reflective telescope with an aperture of 200 mm. On the ground station, a telescope with an aperture of 1200 mm collects the signal photons. A stable and high-transmittance communication channel is set up with a high-precision bidirectional tracking system, a polarization compensation module, and a synchronization system. When the quantum link is successfully established, we obtain a key rate over 100 bps with a communication distance up to 719 km. Together with our recent development of QKD in daylight, the present demonstration paves the way towards a practical satellite-constellation-based global quantum secure network with small-sized QKD payloads.

Objective. To investigate the utility of AD8 for cognitive impairment in a Chinese physical examination population.Methods. Military cadres who took routine physical examination in Chinese PLA General Hospital from Jan 1, 2013, to Dec 31, 2013, were subjected to AD8 scale. Individual information such as age, gender, and education was also collected. All data were analyzed by SPSS 19.0.Results. 1544 subjects were enrolled in this study with mean age 75.4 ± 10.6 years. The subjects who scored 0 to 8 of AD8 scale were 1015, 269, 120, 60, 30, 14, 19, 8, and 9, respectively. Corresponding proportions were 65.7%, 17.4%, 7.8%, 3.9%, 2.0%, 0.9%, 1.2%, 0.5%, and 0.6%, respectively. The endorsement prevalence of 8 questions was 5.6%, 9.2%, 6.6%, 9.2%, 4.8%, 4.5%, 8.9%, and 24.1%, respectively. The endorsement prevalence of question 8 was significantly higher than others (P<0.05). 260 subjects were scored equal to or greater than 2. The abnormal rate was 16.9%. All the participants were stratified into 9 groups by age; the prevalence of dementia was highly correlated with age (P<0.01).Conclusion. AD8 scale is a convenient and effective tool for cognitive screening in routine physical examination population.

MnxS (where 0.05

This paper proposed a model of the tracking system for space quantum communication. The entire model includes a coarse tracking system and a fine tracking system. In matlab/simulink environment, simulation is done with this model in different working conditions. The result of simulation is compared with the experiment result of the actual developed quantum communication tracking system, it confirm the validity of the proposed model. According to the simulation, the performance of the space quantum communication tracking system can be evaluated.

A third generation of synchrotron radiation facilities is coming on line worldwide, whose brilliance exceeds previous ultraviolet and x-ray light sources by four orders of magnitude. The capabilities at second and third generation light sources are discussed, using examples in surface and interface chemistry and magnetic nanostructures. The authors' experience at the IBM-Tennessee-Tulane-LLNL-LBL undulator beam line will serve as a hands-on guide for work at one of the new facilities.

The IBM/TENN/TULANE/LLNL/LBL Beamline 8.0 at the advanced light source combining a 5.0 cm, 89 period undulator with a high‐throughput, high‐resolution spherical grating monochromator, provides a powerful excitation source over a spectral range of 70–1200 eV for surface physics and material science research. The beamline progress and the first experimental results obtained with a fluorescence end station on graphite and titanium oxides are presented here. The dispersive features in K emission spectra of graphite excited near threshold, and found a clear relationship between them and graphite band structure are observed. The monochromator is operated at a resolving power of roughly 2000, while the spectrometer has a resolving power of 400 for these fluorescence experiments.

Quantum key distribution (QKD), provides the only intrinsically unconditional secure method for communication based on principle of quantum mechanics. Compared with fiber-based demonstrations-, free-space links could provide the most appealing solution for much larger distance. Despite of significant efforts, so far all realizations rely on stationary sites. Justifications are therefore extremely crucial for applications via a typical Low Earth Orbit Satellite (LEOS). To achieve direct and full-scale verifications, we demonstrate here three independent experiments with a decoy-state QKD system overcoming all the demanding conditions. The system is operated in a moving platform through a turntable, a floating platform through a hot-air balloon, and a huge loss channel, respectively, for substantiating performances under rapid motion, attitude change, vibration, random movement of satellites and in high-loss regime. The experiments cover expanded ranges for all the leading parameters of LEOS. Our results pave the way towards ground-satellite QKD and global quantum communication network., Comment: 17 pages, 3 figures, 2 tables

Several generic spectrometer types have been developed for research using VUV light at synchrotron radiation sources. They all have used gratings with a constant groove spacing and they all have tried to incorporate high resolution, high throughput, rejection of second and higher order radiation, and design simplicity in their construction. The use of gratings ruled with variable spaced grooves to reduce defocus, coma, and spherical aberration was suggested almost twenty years ago. An instrument using this grating concept was built five years ago for conventional sources. The first monochromator using a variable line spaced grating was installed at the National Synchrotron Light Source almost two years ago, and a high resolution version of such an instrument has been built at the Synchrotron Radiation Center operated by the University of Wisconsin. In this presentation we review the development of monochromators using variable line space gratings and the possible applications of this type of instrumentation.

We have recently begun a series of upgrades to the NIST/ARPA National Reflectometry Facility at the Synchrotron Ultraviolet Radiation Facility. The facility currently consists of a new monochromator and the original sample manipulator which allows us to measure optical components less than 10 cm in diameter. The monochromator offers high throughput and modest resolution over the wavelength range 3.5-40 nm. In the next year we will be installing a sample manipulator that will be able to accommodate the much larger optics that will be used in future x-ray projection lithography and astronomy instruments. We offer preliminary measurements of the throughput and resolution of the new monochromator.

Spaceborne laser rangefinder is one of the main payloads in earth observation satellites and lunar satellites. In this paper, the ranging sensitivity and accuracy of the spaceborne laser rangefinder have been discussed. And a photon counting detected mode is recommended to improve the rangefinder's sensitivity and the accuracy. A future laser rangefinder system has been designed and it's proved to be available by the test of the prototype.

In this paper, we present and analyze an improved spectrometer design that has evolved from studies of the focal properties of transmission gratings in converging ligid beams. This design uses a variable line space grating at a fixed angle of incidence to focus the diffracted light in one dimension, producing resolutions in excess of 1000 over a large wavelength region. Attractive features of this concept include high throughout, simple wavelenght scanning, simple optical elements (plane gratings and plane and toroidal mirrors), and relatively inexpensive realizations. After presenting a mathematical analysis of the primary design features, we discuss implementations of this design both as a spectrometer and as two versions of beamline monochromators. Design parameters for the two monochromators will be given.

This paper introduces a skill but practical optical model of developing wide field of view push-broom hyperspectral imager. Usually, the field of view of a push-broom hyperspectral imaging sensor is less than 30 degrees, and it can not meet the requirement for typical earth observation mission. This paper addresses the difficulty of developing wide field of view imaging sensor and presents an optical model of wide field of view hyperspectal imager. The optical model of hyperspectral imager is composed of a large field of view lens, a long entrance slit, two spectrometers and two area detector arrays and has a cross-track field of view of 60 degrees. The lens images a ground belt onto the long entrance slit, the slit acts as a field stop and allow only light from a linear belt in the scene to enter the imager. The light passing through the long slit is divided two equal parts using a special skill and it is separated and imaged on the area detector arrays by the two spectrometer. The analysis shows that the wide field of view hyperspectral imager doesn't drop down the spatial resolution.

The geometric and electronic structure of a buried monolayer of boron nitride (BN) has been probed using resonant soft x‐ray fluorescence (SXF). By using the strong π* resonance feature in the resonant fluorescence spectrum near the B (1s) threshold, we were able to detect the BN thin film and examine changes in its electronic structure when the monolayer is placed between different materials. Our results demonstrate the capability of the resonant SXF technique for probing the element‐specific electronic structure of a buried thin film nondestructively.

Si L 2.3 x-ray emission stimulated with narrow-band synchrotron radiation has been studied as a function of excitation energy. In strong contrast to crystalline silicon, amorphous silicon yields emission spectra that are independent of the excitation energy, thereby demonstrating that long-range order plays a necessary role in the excitation-energy dependence of the crystalline emission

This paper is a summary of some of the recent activities of our soft x-ray spectroscopy group. We are using soft x-ray emission spectroscopy to probe the electronic properties of matter, emphasizing atoms in the bulk and at interfaces. In particular we have used incoherent photon excitation to obtain a basic understanding of the electronic properties of a wide variety of materials such as yttrium oxide and titanium diboride, we have used the penetrating power of x-rays to study multilayers of silicon and iron and have shown that iron silicide is present in the silicon layer and provides evidence that in the antiferromagnetic Fe/Si multilayer system the FeSi2 layer is conducting rather than insulating. The ubiquitous presence of Raman scattering has been used to elucidate the electronic band structure of materials including graphite and hexagonal boron nitride. Such scattering can produce dramatic changes in the emission spectrum that can further the basic understanding of the electronic band structure. We...

Soft x-ray fluorescence spectroscopy provides an element and angular momentum selective measure of the valence band density of states in complex materials. Results are presented demonstrating the use of SXF both as a means of solving materials problems and as a means of increasing our fundamental understanding of low energy excitation processes in various types of materials. As examples of materials applications, we discuss the L2,3 spectra of Si in various environments, and describe radiation damage studies in Beryl. Fundamental new insights are provided by the study of SXF spectra excited near an x-ray threshold. For such excitation, recent work demonstrates that an electronic Raman scattering process can greatly modify the normal fluorescence spectrum. We discuss near threshold studies of graphite, h-BN and NiS to demonstrate that the nature of the electronic excitation processes differs dramatically in various classes of materials and provides important new insights into their properties.

This article illustrates the use of synchrotron radiation for illuminating the electronic structure of surfaces. After a brief introduction into the most common spectroscopies, their capabilities are exposed by a set of examples from the authors’ area of expertise. It comprises the surface and interface chemistry of semiconductors and magnetic materials, but leaves out a large body of work on surface chemistry of heterogeneous catalysis.