A review and bibliometric analysis of global research on proton radiotherapy.

Proton beam therapy (PBT) has great advantages as tumor radiotherapy and is progressively becoming a more prevalent choice for individuals undergoing radiation therapy. The objective of this review is to pinpoint collaborative efforts among countries and institutions, while also exploring the hot topics and future outlook in the field of PBT. Data from publications were downloaded from the Web of Science Core Collection. CiteSpace and Excel 2016 were used to conduct the bibliometric and knowledge map analysis. A total of 6516 publications were identified, with the total number of articles steadily increasing and the United States being the most productive country. Harvard University took the lead in contributing the highest number of publications. Paganetti Harald published the most articles and had the most cocitations. PHYS MED BIOL published the greatest number of PBT-related articles, while INT J RADIAT ONCOL received the most citations. Paganetti Harald, 2012, PHYS MED BIOL can be classified as classic literature due to its high citation rate. We believe that research on technology development, dose calculation and relative biological effectiveness were the knowledge bases in this field. Future research hotspots may include clinical trials, flash radiotherapy, and immunotherapy.

Enhanced peroxidase-like activity of Cu-Cu2O composite film through PtPd immobilization for colorimetric glucose detection.

In this study, Cu-Cu2O/PtPd nanocomposites were synthesized and characterized for their peroxidase-like enzyme activity. X-ray diffraction and energy dispersive X-ray spectroscopy analyses confirmed the successful synthesis of the nanocomposites, which exhibited a flower-like morphology and a more uniform dispersion than Cu-Cu2O. The catalytic activity of Cu-Cu2O/PtPd was evaluated using the chromogenic substrate 3,3',5,5'-tetramethylbenzidine (TMB), finding that Cu-Cu2O/PtPd outperformed Cu-Cu2O. The optimal temperature and pH for the catalytic activity of Cu-Cu2O/PtPd were determined to be 40 °C and pH 4.0, respectively. A kinetic analysis revealed that Cu-Cu2O/PtPd followed Michaelis-Menten kinetics and exhibited a higher affinity toward TMB than the horseradish peroxidase enzyme. The catalytic mechanism of Cu-Cu2O/PtPd involved the generation of hydroxyl radicals, which facilitated the oxidation of TMB. Furthermore, the Cu-Cu2O/PtPd nanocomposite was successfully applied for the colorimetric detection of glucose, demonstrating a linear range of 8-90 µM, a detection limit of 2.389 µM, and high selectivity for glucose over other sugars.

Functional connectivity analysis on electroencephalography signals reveals potential biomarkers for treatment response in major depression.

BACKGROUND: The treatment efficacy varies across individual patients with major depressive disorder (MDD). It lacks robust electroencephalography (EEG) markers for an antidepressant-responsive phenotype. METHOD: This is an observational study enrolling 28 patients with MDD and 33 healthy controls (mean age of 40.7 years, and 71.4% were women). Patients underwent EEG exams at baseline (week0) and week1, while controls' EEG recordings were acquired only at week0. A resting eye-closing EEG segment was analyzed for functional connectivity (FC). Four parameters were used in FC analysis: (1) node strength (NS), (2) global efficiency (GE), (3) clustering coefficient (CC), and (4) betweenness centrality (BC). RESULTS: We found that controls had higher values in delta wave in the indices of NS, GE, BC, and CC than MDD patients at baseline. After treatment with antidepressants, patients' FC indices improved significantly, including GE, mean CC, and mean NS in the delta wave. The FC in the alpha and beta bands of the responders were higher than those of the non-responders. CONCLUSIONS: The FC of the MDD patients at baseline without treatment was worse than that of controls. After treatment, the FC improved and was close to the values of controls. Responders showed better FC in the high-frequency bands than non-responders, and this feature exists in both pre-treatment and post-treatment EEG.

Evaluation of tubal patency by hysterosalpingo-contrast Sonography (HyCoSy): Controversies, dilemmas and considerations.

Evaluation of tubal patency is one of the vital steps in the process of female infertility management. Hysterosalpingo-contrast Sonography (HyCoSy) has become the first-line recommendation for evaluating tubal patency. However, there remain some controversies and dilemmas relevant to the evaluation of tubal patency by HyCosy, with no effective solution has been proposed or no consensus has been reached. Herein, combined with previous research and clinical experience, we conclude and analyze these controversies and dilemmas, aiming at offering our perspective on the opportunities and challenges which are faced by HyCosy.

Comparative study of the clinical efficacy of all-inside and traditional techniques in anterior cruciate ligament reconstruction.

BACKGROUND: Many studies have focused on the femoral tunnel technique and fixation method, but few studies have involved the tibial tunnel technique and fixation method. The all-inside technique is one of the new techniques that has been described in recent years. All-inside anterior cruciate ligament (ACL) reconstruction is based on a tibial socket instead of a full tunnel. This method has many potential advantages. AIM: To compare clinical outcomes of knee ACL autograft reconstruction using all-inside quadrupled semitendinosus (AIST) and traditional hamstring tendon (TBT) techniques. METHODS: From January 2017 to October 2019, the clinical data of 80 patients with ACL reconstruction were retrospectively analyzed, including 67 males and 13 females. The patients had an average age of 24.3 ± 3.1 years (age range: 18-33 years). The AIST technique was used in 42 patients and the TBT technique was used in 38 patients. The time between operation and injury, operative duration, postoperative visual analogue scale (VAS) score and knee functional recovery were recorded and compared between the two groups. The International Knee Documentation Committee (IKDC) and Lysholm scoring system were used to comprehensively evaluate clinical efficacy. RESULTS: Eighty patients were followed for 24-36 mo, with an average follow-up duration of 27.5 ± 1.8 mo. There were no significant differences in the time between surgery and injury, operative duration, IKDC and Lysholm scores of the affected knee at the last follow-up evaluation between the two groups. There were significant differences in VAS scores 1 d, 3 d, 7 d, 2 wk and 1 mo after surgery (P < 0.05). There was no significant difference in VAS score at 3 mo, 6 mo and 1 year after operation. CONCLUSION: The efficacy of the AIST ACL reconstruction technique was comparable to the TBT technique, but the postoperative pain was less with the AIST technique. Thus, the AIST technique is an ideal treatment choice for ACL reconstruction.

Platelet-rich plasma promotes skeletal muscle regeneration and neuromuscular functional reconstitution in a concentration-dependent manner in a rat laceration model.

Abnormal function of injured muscle with innervation loss is a challenge in sports medicine. The difficulty of rehabilitation is regenerating and reconstructing the skeletal muscle tissue and the neuromuscular junction (NMJ). Platelet-rich plasma (PRP) releases various growth factors that may provide an appropriate niche for tissue regeneration. However, the specific mechanism of the PRP's efficacy on muscle healing remains unknown. In this study, we injected PRP with different concentration gradients (800, 1200, 1600 × 109 pl/L) or saline into a rat gastrocnemius laceration model. The results of histopathology and neuromyography show that PRP improved myofibers regeneration, facilitated electrophysiological recovery, and reduced fibrosis in a concentration-dependent manner. Furthermore, we found that PRP promotes the activity of satellite cells by upregulating the expression of the myogenic regulatory factor (MyoD, myogenin). Meanwhile, PRP promotes the regeneration and maturation of acetylcholine receptor (AChR) clusters of the Neuromuscular junction (NMJ) on the regenerative myofibers. Finally, we found that the expression of the Agrin, LRP4, and MuSK was upregulated in the PRP-treated groups, which may contribute to AChR cluster regeneration and functional recovery. The conclusions proposed a hypothesis for PRP treatment's efficacy and mechanism in muscle injuries, indicating promising application prospects.

Hip Arthroscopy With Fluoroscopy-Free Technique for the Treatment of Femoroacetabular Impingement.

Hip arthroscopy is the predominant surgical procedure for the treatment of femoroacetabular impingement syndrome (FAI). Usually, hip arthroscopy requires intraoperative fluoroscopic guidance for portal establishment, acetabuloplasty, suture anchor placement, and femoroplasty, which has disadvantages such as radiation exposure and prolonged operative time. This article presents a technique of hip arthroscopy without fluoroscopy throughout. By establishing portals through a semiopen hollow guide bar, "one-line trimming" for pincer deformity removal, modified distal anterolateral portal for anchor placement, "triangular abrasion" for cam deformity resection, and intraoperative dynamic examination to ensure adequate relief of impingement, we provide a safe and effective surgical procedure for hip arthroscopy to treat FAI without fluoroscopy.

Temporal optical activity and chiral time-interfaces [Invited].

Time-interfaces, at which the optical properties of a medium undergo abrupt and spatially uniform changes, have attracted surging interest in optics and wave physics. In this work, we study wave scattering at time-interfaces involving chiral media. Dual to spatial interfaces involving chiral media, we show that a propagating wave is split upon a chiral time-interface into two orthogonal circular polarization waves oscillating at different frequencies. We formulate the temporal scattering boundary-value problem at such time-interfaces, and then demonstrate the effect of temporal optical activity through a chiral time-slab. The effect of material dispersion is also analyzed, highlighting interesting opportunities in which multiple scattered waves emerge form the time-interface and interfere. Our results pave the way towards time-metamaterials encompassing chirality as an additional degree of freedom for wave manipulation, offering opportunities for temporal circular dichroism and negative refraction at time-interfaces.

Prevalence of possible sarcopenia in community-dwelling older Chinese adults: a cross-sectional study.

OBJECTIVES: To determine the prevalence of possible sarcopenia and its association with other conditions in older adults in Bengbu, China. DESIGN, SETTING AND PARTICIPANTS: A cross-sectional study of 1082 community-dwelling Chinese people aged at least 60 years from March to June 2022. METHODS: Handgrip strength and information regarding associated conditions were collected. Possible sarcopenia was estimated based on handgrip strength with cut-off values (<28 kg in men; <18 kg in women) recommended by the Asia Working Group for Sarcopenia in 2019. Mann-Whitney U tests, χ2 tests and binary logistic regression analyses were used to explore relationships between possible sarcopenia and associated conditions. RESULTS: Possible sarcopenia was more prevalent in men (52.79%, n=246, age 79.43±7.33 years among men with possible sarcopenia) than in women (44.48%, n=274, age 78.90±7.71 years among women with possible sarcopenia). In men, possible sarcopenia positively correlated with high age (OR 2.658, 95% CI 1.758 to 4.019), physical inactivity (OR 2.779, 95% CI 1.646 to 4.691) and diabetes (OR 4.269, 95% CI 2.397 to 7.602), and negatively with hypertension (OR 0.586, 95% CI 0.384 to 0.893). The risk of possible sarcopenia in men decreased by 12.6% for every 1 kg/m2 increase of body mass index (OR 0.874, 95% CI 0.817 to 0.935). In women, possible sarcopenia positively correlated with high age (OR 3.821, 95% CI 2.677 to 5.455), physical inactivity (OR 2.185, 95% CI 1.488 to 3.210) and arthritis (OR 2.076, 95% CI 1.411 to 3.056). CONCLUSION: Possible sarcopenia is prevalent in older adults and the factors affecting possible sarcopenia are different in men and women. Health education about these target factors can be considered as a potential measure to prevent possible sarcopenia.

Models for resonant acoustic metasurfaces with application to moth wing ultrasound absorption.

Taking as bioinspiration the remarkable acoustic absorption properties of moth wings, we develop a simple analytical model that describes the interaction between acoustic pressure fields, and thin elastic plates incorporating resonant sub-structures. The moth wing is an exemplar of a natural acoustic metamaterial; the wings are deeply subwavelength in thickness at the frequencies of interest, the absorption is broadband and the tiny scales resonate on the moth wing acting in concert. The simplified model incorporates only the essential physics and the scales are idealized to flat rigid rectangular plates coupled via a spring to an elastic plate that forms the wing; all the components are deep-subwavelength at desired frequencies. Based on Fourier analysis, complemented by phenomenological modelling, our theory shows excellent agreement with simulation mimicking the moth-wing structure. Moth wings operate as broadband sound absorbers employing a range of scale sizes. We demonstrate that a random distribution of scale sizes generates a broadband absorption spectrum. To further illustrate the potential of the model, we design a deeply sub-wavelength acoustic counterpart of electromagnetically induced reflectance. This article is part of the theme issue 'Wave generation and transmission in multi-scale complex media and structured metamaterials (part 2)'.

Arthroscopy with subscapularis upper one-third tenodesis for treatment of recurrent anterior shoulder instability independent of glenoid bone loss.

BACKGROUND: Recurrent anterior shoulder instability is a common traumatic injury, the main clinical manifestation of which is recurrent anteroinferior dislocation of the humeral head. The current follow-up study showed that the effect of arthroscopic Bankart repair is unreliable. AIM: To evaluate the clinical efficacy of arthroscopy with subscapularis upper one-third tenodesis for treatment of anterior shoulder instability, and to develop a method to further improve anterior stability and reduce the recurrence rate. METHODS: Between January 2015 and December 2018, male patients with recurrent anterior shoulder instability were selected. One hundred and twenty patients had a glenoid defect < 20% and 80 patients had a glenoid defect > 20%. The average age was 25 years (range, 18-45 years). Patients with a glenoid defect < 20% underwent arthroscopic Bankart repair with a subscapularis upper one-third tenodesis. The patients with a glenoid defect > 20% underwent an arthroscopic iliac crest bone autograft with a subscapularis upper one-third tenodesis. All patients were assessed with Rowe and Constant scores. RESULTS: The average shoulder forward flexion angle was 163.6° ± 8.3° and 171.8° ± 3.6° preoperatively and at the last follow-up evaluation, respectively. The average external rotation angle when abduction was 90° was 68.4° ± 13.6° and 88.5° ± 6.2° preoperatively and at the last follow-up evaluation, respectively. The mean Rowe scores preoperatively and at the last follow-up evaluation were 32.6 ± 3.2 and 95.2 ± 2.2, respectively (P < 0.05). The mean Constant scores preoperatively and at the last follow-up evaluation were 75.4 ± 3.5 and 95.8 ± 3.3, respectively (P < 0.05). No postoperative dislocations were recorded by the end of the follow-up period. CONCLUSION: Arthroscopy with subscapularis upper one-third tenodesis was effective for treatment of recurrent anterior shoulder instability independent of the size of the glenoid bone defect, enhanced anterior stability of the shoulder, and did not affect postoperative range of motion of the affected limb.

[Spatial-temporal Distribution and Evolution Characteristics of Air Pollution in Beijing-Tianjin-Hebei Region Based on Long-term "Ground-Satellite" Data].

This study aimed to promote the coordinated development of regional social economy and ecological environment, build a better living environment, accurately prevent and control pollution, and carry out in-depth surveys and general surveys of air pollution in Beijing, Tianjin, and Hebei. Based on 6 years (June 2014 to December 2019) of ground environmental observation data and satellite data from 2000 to 2019, the distribution characteristics and evolution trend of air pollution in different time and spatial scales were analyzed. The results showed that:① according to the daily average concentration of PM2.5 at the sites, the pollution in the Beijing-Tianjin-Hebei region showed the characteristics of more days, heavy levels, and overall improvement. Pollution mainly occurred from October to April of the following year, accounting for nearly half a year. The pollution level of PM2.5 was the best at Zhangjiakou, followed by Qinhuangdao. ② Based on the 20-year average PM2.5 annual average concentration data retrieved from satellites, the PM2.5 concentration presented a spatial distribution characteristic in which that in the plains was higher than that in mountain area, and PM2.5 concentration in the city was higher than that in the suburbs. PM2.5 concentration changed with time, showing a four-stage bimodal structure of "M"-type evolution characteristics, which gradually increased starting in 2000; the first peak appeared in 2006 and gradually decreased from 2007 to 2012. It rose sharply to the second peak in 2013 and then decreased yearly until 2017. ③ The monthly average AOT data based on satellites every 10 years indicated that the value of AOT in the first time period (2000-2009) was larger than that in the same month of the second time period (2010-2019). The maximum value was in July, and the minimum value was in December. The monthly average AOT in Zhangjiakou and Chengde changed slightly over the past 20 years, and the seasonal and spatial differences were significant in the plain area. ④ Judging from the daily average value of O3-8h observed at the stations, good levels of O3-8h concentrations in the Beijing-Tianjin-Hebei area occurred frequently and widely from March to October. There were at least seven instances of light pollution levels, and the moderate pollution levels and above were not observed. ⑤ The daily average value of SO2 observed on the ground showed that there was no light pollution or above; the good pollution level occurred in winter, and most appeared in the form of pollution for several consecutive days. ⑥ The analysis of AQI data revealed that from 2015 to 2019, the proportion of AQI excellent grades in Beijing increased from 27% to 38%, and the proportion of Tianjin AQI good grades increased from 44% to 64%. The highest proportion of Handan AQI superior grades appeared in 2016, accounting for only 9%. ⑦ The 20-year monthly average concentration of SO2 data based on satellites showed that high-value areas were in Handan, Xingtai, and Shijiazhuang, and low-value areas were in Zhangjiakou and Chengde. The 20-year average NO2 data showed that the high-value centers were in Beijing, Tianjin, Tangshan, Handan, Xingtai, and Shijiazhuang.

[Arthroscopic Pushlock anchor fixation with iliac creast bone autograft in the treatment of recurrent anterior shoulder instability with critical bone defect].

OBJECTIVE: To evaluate the effectiveness of arthroscopic Pushlock anchor fixation with iliac creast bone autograft in the treatment of recurrent anterior shoulder instability with critical bone defect. METHODS: The clinical data of 80 patients with recurrent anterior shoulder instability with critical bone defect treated by arthroscopic Pushlock anchor fixation with iliac creast bone autograft between January 2016 and January 2019 were retrospectively analyzed. The patients were all male; they were 18-45 years old at the surgery, with an average of 25 years old. The disease duration ranged from 3 months to 5 years, with an average of 2 years. The shoulder joint dislocated 3-50 times, with an average of 8 times. X-ray films, MRI, CT scans and three-dimensional reconstruction of the shoulder were performed before operation. The area of the anterior glenoid defect was 25%-45%, with an average of 27.3%. The shoulder mobility (forward flexion and external rotation in abduction at 90°), the Constant-Murley score, and the Rowe score were used to evaluate the shoulder function before operation and at last follow-up. RESULTS: Patients were followed up 1-3 years, with an average of 2 years. No shoulder dislocation occurred again during follow-up. All partial graft absorption occurred after operation, CT scan showed that the graft absorption ratio was less than 30% at 1 week and 3 months after operation. CT three-dimensional reconstruction at 1 year after operation showed that all grafts had healed to the glenoid. The anterior glenoid bone defect was less than 5% (from 0 to 5%, with an average of 3.2%). At last follow-up, the shoulder mobility (forward flexion and external rotation in abduction at 90°), the Constant-Murley score, and the Rowe score significantly improved when compared with preoperative ones ( P<0.05). The shoulder mobility of external rotation in abduction at 90° of the affected side limited when compared with the healthy side [(6.7±5.1)°]. CONCLUSION: Arthroscopic Pushlock anchor fixation with iliac creast bone autograft has a good effectiveness in the treatment of recurrent anterior shoulder instability with critical bone defect. The method is relatively simple and the learning curve is short.

Cytotoxic and Anti-Inflammatory Triterpenoids in the Vines and Leaves of Momordica charantia.

The vines and leaves of Momordica charantia L. are used as herbal medicines to treat inflammation-related disorders. However, their safety profile remains uncharacterized, and the constituents in their extracts that exert anti-inflammatory and adverse effects remain unclear. This study isolated the characteristic cucurbitane-type triterpenoid species in the vines and leaves of M. charantia L. and analyzed their cytotoxicity, anti-inflammatory effects, and underlying mechanisms. Four structurally related triterpenoids-momordicines I, II, IV, and (23E) 3ß,7ß,25-trihydroxycucurbita-5,23-dien-19-al (TCD)-were isolated from the triterpenoid-rich fractions of extracts from the vines and leaves of M. charantia. Momordicine I was cytotoxic on normal cells, momordicine II exerted milder cytotoxicity, and momordicine IV and TCD had no obvious adverse effects on cell growth. TCD had anti-inflammatory activity both in vivo and in vitro. In lipopolysaccharide-stimulated RAW 264.7 cells, TCD inhibited the inhibitor kappa B kinase/nuclear factor-κB pathway and enhanced the expression of nuclear factor erythroid 2-related factor 2, heme oxygenase-1, and glutamate-cysteine ligase modifier subunit through the extracellular signal-regulated kinase1/2 and p38. Thus, the vines and leaves of M. charantia should be used with caution. An extraction protocol that can enrich TCD but remove momordicine I would likely enhance the safety of the extract.

The future urban growth under policies and its ecological effect in the Jing-Jin-Ji area, China.

Since 2016, the Chinese government has invoked some policies to make Jing-Jin-Ji (JJJ) a new urban agglomeration. However, there has been no research to study the effect of these new policies on future urban growth. This study assessed part of these new policies on JJJ urban growth in 2020-2050 using SLEUTH model. Then the ecological effects of the urban growth are evaluated. Results showed the policies had nearly no obvious impact on the whole JJJ urban growth, but affected sub-regional (Beijing, Tianjin and Hebei, respectively) urban growth. Under ecological protection in future, the value of ecological service in JJJ would increase to a maximum of 31.7×108 Yuan/km2 in 2031. The ecological elasticity also increased and the ecological risk was strongly reduced around the present urban area. This ecologically sustainable development is critical to the future urban growth, and should be considered more carefully by urban planners and managers. More policies should be evaluated for JJJ urban growth in future work.

Cyclotetrabenzoin Acetate: A Macrocyclic Porous Molecular Crystal for CO2 Separations by Pressure Swing Adsorption*.

A porous molecular crystal (PMC) assembled by macrocyclic cyclotetrabenzoin acetate is an efficient adsorbent for CO2 separations. The 7.1×7.1 Šsquare pore of PMC and its ester C=O groups play important roles in improving its affinity for CO2 molecules. The benzene walls of macrocycle engage in an apparent [π⋅⋅⋅π] interaction with the molecule of CO2 at low pressure. In addition, the polar carbonyl groups pointing inward the square channels reduce the size of aperture to a 5.0×5.0 Šsquare, which offers kinetic selectivity for CO2 capture. The PMC features water tolerance and high structural stability under vacuum and various gas adsorption conditions, which are rare among intrinsically porous organic molecules. Most importantly, the moderate adsorbate-adsorbent interaction allows the PMC to be readily regenerated, and therefore applied to pressure swing adsorption processes. The eluted N2 and CH4 are obtained with over 99.9 % and 99.8 % purity, respectively, and the separation performance is stable for 30 cycles. Coupled with its easy synthesis, cyclotetrabenzoin acetate is a promising adsorbent for CO2 separations from flue and natural gases.

The scattering of sound by objects with dynamic deformations.

In this article, a sonic scattering problem of arbitrarily shaped, time-varying rigid surfaces is analytically solved by exploiting perturbation theory. The results demonstrate multi-frequency scattering characteristics resulting from a single moving object and the nonreciprocity from spinning components. The proposed approach is numerically verified, from audio through to ultrasonic frequencies, by full-wave simulation based on the finite-element method. This numerical simulation also validates the non-reciprocal phenomenon in such systems. In addition, the theory for multiple Floquet scattering of sound is built, which lays the foundation for advanced studies relevant to Floquet phononic crystals and novel time-varying sonic devices.

Effect of Combined Sorafenib/Cisplatinum Treatment on the Autophagy and Proliferation of Hepatocellular Carcinoma hepG2 Cells in Vitro.

OBJECTIVE: To explore the effect of combined Sorafenib/ cisplatinum treatment on the autophagy and proliferation of hepatocellular carcinoma (HepG2) cells in vitro. METHODS: HepG2 cells were cultured and treated with different concentrations of Sorafenib, cisplatinum, or a combination of both over a 24-hour period. Cell proliferation was evaluated using a CCK8 assay, and the mRNA expression of the autophagy-related proteins AKT, mTOR, and LC3 were detected using quantitative PCR (qPCR). AKT, pAKT (Ser473), mTOR, pmTOR (Ser2448), LC3I, and LC3II protein expression levels were evaluated by western blot. RESULTS: We found that the survival rate of HepG2 cells was 47.42% when treated with Sorafenib (10 µmol/L) monotherapy, and 46.04% when treated with cisplatinum (10 mg/L) monotherapy. When Sorafenib(10 µmol/L) was combined with cisplatinum (10 mg/L), the cellular proliferation and survival rate was only 16.71% ( P <0.05). qPCR and western blot revealed that a combination of Sorafenib (10 µmol/L) and cisplatinum (10 mg/L) reduced the transcription and protein expression of autophagy-related AKT and mTOR but increased that of LC3 (P <0.05). CONCLUSION: Combining Sorafenib and cisplatinum can effectively induce cell autophagy and reduce cellular proliferation via the PI3K/AKT/mTOR signal pathway.
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Wood Anomalies and Surface-Wave Excitation with a Time Grating.

In order to confine waves beyond the diffraction limit, advances in fabrication techniques have enabled subwavelength structuring of matter, achieving near-field control of light and other types of waves. The price is often expensive fabrication needs and the irreversibility of device functionality, as well as the introduction of impurities, a major contributor to losses. In this Letter, we propose temporal inhomogeneities, such as a periodic drive in the electromagnetic properties of a surface which supports guided modes, as an alternative route for the coupling of propagating waves to evanescent modes across the light line, thus circumventing the need for subwavelength fabrication, and achieving the temporal counterpart of the classical Wood anomaly. We show analytically and numerically how this concept is valid for any material platform and at any frequency, and propose and model a realistic experiment in graphene to couple terahertz radiation to plasmons with unit efficiency, demonstrating that time modulation of material properties could be a tunable, lower-loss and fast-switchable alternative to the subwavelength structuring of matter for near-field wave control.

[Characteristics of Spatial and Temporal Evolution and Investigation of Air Pollution in Guangdong-Hong Kong-Macao Greater Bay Area Based on Ground-Space Observation Data].

The temporal and spatial distribution characteristics, evolution trend and potential climatic effects of air pollution in the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) were analyzed on different time scales and spatial spaces, based on ground environment observation data from June 2014 to December 2018 and satellite remote sensing inversion products from 2000 to 2018. The results show that:① From the in-situ observed daily average concentration of PM2.5, good or mild to moderate pollution occurred in January, February, October, November, and December every year, and the rest of the time was excellent. ② Based on the annual average PM2.5 concentration obtained by satellite for the past 20 years, the spatial characteristics showed that the external radiation is centered on Guangzhou and Foshan. The time evolution shows the characteristics of an Ω shape, which increases gradually from 2000 to 2009, is highest in 2008, and then gradually decreases. ③ The monthly average aerosol optical thickness (AOT) value from the Multi-angle Imaging Spectro Radiometer satellite reversion every 10 years for a period (2000-2009 for a period, 2010-2018 for a period) was used to see the monthly variation. The monthly average AOT value in the first period was larger than that in the second period of the same month, the maximum value was in March and April, and the minimum value was in November and December. It is envisaged to draw a line along the north-south direction of the Pearl River Port, which basically shows that the AOT value in the west is greater than that in the east. ④ According to the observed daily average concentration data of O3-8h, the main concentration level of O3-8h in the GBA is excellent. The cities with good ozone concentration were most numerous in 2014, with five cities, and least in 2018, with only one city. The highest ozone concentration was in September, followed by June and November, and then May and July. In the past 20 years, the spatial distribution of the average concentration of O3 monitored by satellite remote sensing showed a characteristic Ω shape, increasing initially and then decreasing. The maximum value was in May, and the north-south boundary line appeared in space. ⑤ There is a good linear relationship between the interannual variation of monthly mean temperature and radiation, whereas the relationship between AOT and radiation cannot be described by a simple linear relationship.