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Phase characterisation of metalenses
Metalenses have emerged as a new optical element or system in recent years, showing superior performance and abundant applications. However, the phase distribution of a metalens has not been measured directly up to now, hindering further quantitative evaluation of its performance. We have developed an interferometric imaging phase measurement system to measure the phase distribution of a metalens by taking only one photo of the interference pattern. Based on the measured phase distribution, we analyse the negative chromatic aberration effect of monochromatic metalenses and propose a feature size of metalenses. Different sensitivities of the phase response to wavelength between the Pancharatnam-Berry phase-based metalens and propagation phase-reliant metalens are directly observed in the experiment. Furthermore, through phase distribution analysis, it is found that the distance between the measured metalens and the brightest spot of focusing will deviate from the focal length when the metalens has a low nominal numerical aperture, even though the metalens is ideal without any fabrication error. We also use the measured phase distribution to quantitatively characterise the imaging performance of the metalens. Our phase measurement system will help not only designers optimise the designs of metalenses but also fabricants distinguish defects to improve the fabrication process, which will pave the way for metalenses in industrial applications.
Journal Article
Love online : emotions on the Internet
This book will change the way you look at cyberspace and love forever. Computers are changing not just the way we work. Falling in & out of love, flirting, cheating, even having sex online have all become part of the modern way of living & loving.
Book
The neurocognitive correlates of brain entropy estimated by resting state fMRI
Resting state brain activity consumes most of brain energy, likely creating and maintaining a reserve of general brain functionality. The latent reserve if it exists may be reflected by the profound long-range fluctuations of resting brain activity. The long-range temporal coherence (LRTC) can be characterized by resting state fMRI (rsfMRI)-based brain entropy (BEN) mapping. While BEN mapping results have shown sensitivity to neuromodulations or disease conditions, the underlying neuromechanisms especially the associations of BEN or LRTC to neurocognition still remain unclear. To address this standing question and to test a novel hypothesis that resting BEN reflects a latent functional reserve through the link to general functionality, we mapped resting BEN of 862 young adults and comprehensively examined its associations to neurocognitions using data from the Human Connectome Project (HCP). Our results unanimously highlighted two brain circuits: the default mode network (DMN) and executive control network (ECN) through their negative associations of BEN to general functionality, which is independent of age and sex. While BEN in DMN/ECN increases with age, it decreases with education years. These results demonstrated the neurocognitive correlates of resting BEN in DMN/ECN and suggest resting BEN in DMN/ECN as a potential proxy of the latent functional reserve that facilitates general brain functionality and may be enhanced by education.
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Journal Article
New frontiers in proton therapy: applications in cancers
Proton therapy offers dominant advantages over photon therapy due to the unique depth-dose characteristics of proton, which can cause a dramatic reduction in normal tissue doses both distal and proximal to the tumor target volume. In turn, this feature may allow dose escalation to the tumor target volume while sparing the tumor-neighboring susceptible organs at risk, which has the potential to reduce treatment toxicity and improve local control rate, quality of life and survival. Some dosimetric studies in various cancers have demonstrated the advantages over photon therapy in dose distributions. Further, it has been observed that proton therapy confers to substantial clinical advantage over photon therapy in head and neck, breast, hepatocellular, and non-small cell lung cancers. As such, proton therapy is regarded as the standard modality of radiotherapy in many pediatric cancers from the technical point of view. However, due to the limited clinical evidence, there have been concerns about the high cost of proton therapy from an economic point of view. Considering the treatment expenses for late radiation-induced toxicities, cost-effective analysis in many studies have shown that proton therapy is the most cost-effective option for brain, head and neck and selected breast cancers. Additional studies are warranted to better unveil the cost-effective values of proton therapy and to develop newer ways for better protection of normal tissues. This review aims at reviewing the recent studies on proton therapy to explore its benefits and cost-effectiveness in cancers. We strongly believe that proton therapy will be a common radiotherapy modality for most types of solid cancers in the future.
Journal Article
الصين والحوكمة العالمية : الاختيار التاريخي
يقدم هذا الكتاب دراسة وافية لأصل وتاريخ الحوكمة العالمية ومسيرة إصلاحها، مع التركيز على دور ومهام مجموعة العشرين وتطورها، ومقارنة بالدراسات السابقة، نجد أن هذا الكتاب يولي اهتماما بالعدالة والثقافة غير الغربية والدول النامية ودورها في الحوكمة العالمية. كما يستعرض الكتاب تاريخ المشاركة الصينية في الحوكمة العالمية وتطورها من الاقصاء إلى الاعتراف بها، ومن المراقبة إلى المشاركة، ومن الدور العادي إلى الدور الفاعل يتطرق الكتاب كذلك إلى قضية الحوكمة الإقليمية والعلاقات الصينية الأمريكية، وكيفية استغلال الصين المزاياها من أجل أداء دورها بشكل أفضل في الشؤون العالمية. وأخيرا، يقدم توصيات سياسية للصين القيادة إصلاح الحوكمة العالمية، وقد استند المؤلف في جميع هذه المحاور على شهاداته الشخصية أثناء أدائه لمهامه الدبلوماسية. يعد هذا الكتاب مرجعا أساسيا للباحثين في الحوكمة العالمية والدراسات الصينية. والعلاقات الدولية. كما أنه مرجع مهم أيضا للمهتمين بالقضايا الدولية، وخاصة الحوكمة العالمية ودور الصين في الساحة الدولية.
Current Clinical Progress of PD-1/PD-L1 Immunotherapy and Potential Combination Treatment in Non–Small Cell Lung Cancer
Conventional methods in treating non–small cell lung cancer contain surgery, chemotherapy, radiotherapy, and targeted therapy, which have various defects. Recently, with the deeper research on tumor immunity, immunotherapy has made the breakthrough in the treatment of cancers. Especially developments of programmed cell death-1/programmed cell death ligand-1 (PD-1/PD-L1) inhibitors bring the therapy into a new stage. This review mainly focuses on introducing existing monoclonal antibodies containing nivolumab, pembrolizumab, atezolizumab, avelumab, and durvalumab, along with 3 ordinary biomarkers such as PD-L1 expression, tumor mutation burden, and microsatellite instability. By understanding the resistance mechanism of anti-PD-1/L1 blockade, research is further improving the survival benefit and expanding the benefit population. So, PD-1/PD-L1 inhibitors begin to be combined with various therapeutic strategies clinically. Discussion and comparison of their effectiveness and safety are also comprehensively reviewed. Meanwhile, we explore the potential, the impact, and mechanisms of combining traditional Chinese medicine with immunotherapy.
Journal Article
Strength deterioration mechanism of bentonite modified loess after wetting–drying cycles
The employment of bentonite modified loess (BML) is a common method of constructing the anti-seepage lining of landfills in the loess region of China, and its long-term secure performance is threatened by wetting–drying (W–D) cycles. Taking the remolded loess (RL) and BML with 15% in mass of bentonite as research objects, the W–D cycles test, scanning electron microscope test and direct shear test were carried out to analyze the effects of W–D cycles on the microstructure and shear strength of samples. The regression equations between strength and micro-pore structure parameters were established by the multivariate linear stepwise regression method. The damage mechanism of BML after W–D cycles was studied by establishing damage degree models based on pore area ratio and cohesion. Results indicate that the water absorption and expansion of bentonite effectively block the intergranular pores, resulting in more medium and small pores and more pronounced surface contact of particles. After W–D cycles, the particle arrangement of samples before and after bentonite modification tends to be loose. Both the pore area ratio and fractal dimension increase and tend to stabilize after five cycles. The BML exhibits lower pore area ratio and greater fractal dimension while its cohesion and internal friction angle show more significant decrease after W–D cycles than those of RL. The damage variables based on pore area ratio and cohesion well describe the W–D induced damage of loess before and after modification from macro- and micro-scale perspectives. The damage degree of samples increases with W–D cycles, but the increment decreases.
Journal Article