Remote sensing of far-red sun-induced chlorophyll fluorescence (SIF) has emerged as an important tool for studying gross primary productivity (GPP) at the global scale. However, the relationship ...between SIF and GPP at the canopy scale lacks a clear mechanistic explanation. This is largely due to the poorly characterized role of the relative contributions from canopy structure and leaf physiology to the variability of the top-of-canopy, observed SIF signal. In particular, the effect of the canopy structure beyond light absorption is that only a fraction (fesc) of the SIF emitted from all leaves in the canopy can escape from the canopy due to the strong scattering of near-infrared radiation. We combined rice, wheat and corn canopy-level in-situ datasets to study how the physiological and structural components of SIF individually relate to measures of photosynthesis. At seasonal time scales, we found a considerably strong positive correlation (R2 = 0.4–0.6) of fesc to the seasonal dynamics of the photosynthetic light use efficiency (LUEP), while the estimated physiological SIF yield was almost entirely uncorrelated to LUEP both at seasonal and diurnal time scales, with the partial exception of wheat. Consistent with these findings, the canopy structure and radiation component of SIF, defined as the product of APAR and fesc, explained the relationship of observed SIF to GPP and even outperformed GPP estimation based on observed SIF at two of the three sites investigated. These results held for both half-hourly and daily mean values. In contrast, the total emitted SIF, obtained by normalizing observed SIF for fesc, improved only the relationship to APAR but considerably decreased the correlation to GPP for all three crops. Our findings demonstrate the dominant role of canopy structure in the SIF-GPP relationship and establish a strong, mechanistic link between the near-infrared reflectance of vegetation (NIRV) and the relevant canopy structure information contained in the SIF signal. These insights are expected to be useful in improving remote sensing based GPP estimates.
•A mechanistic decomposition of canopy SIF for three in situ crop datasets.•The canopy structure and radiation factor outperforms SIF for GPP estimation.•Canopy escape fraction of SIF correlates with photosynthetic light use efficiency.•Correcting SIF for canopy scattering improves the correlation to APAR but not GPP.•Estimates of physiological SIF yield show no clear seasonal patterns.
Infrared radiation emitted from a planet contains information about the chemical composition and vertical temperature profile of its atmosphere. If upper layers are cooler than lower layers, ...molecular gases will produce absorption features in the planetary thermal spectrum. Conversely, if there is a stratosphere-where temperature increases with altitude-these molecular features will be observed in emission. It has been suggested that stratospheres could form in highly irradiated exoplanets, but the extent to which this occurs is unresolved both theoretically and observationally. A previous claim for the presence of a stratosphere remains open to question, owing to the challenges posed by the highly variable host star and the low spectral resolution of the measurements. Here we report a near-infrared thermal spectrum for the ultrahot gas giant WASP-121b, which has an equilibrium temperature of approximately 2,500 kelvin. Water is resolved in emission, providing a detection of an exoplanet stratosphere at 5σ confidence. These observations imply that a substantial fraction of incident stellar radiation is retained at high altitudes in the atmosphere, possibly by absorbing chemical species such as gaseous vanadium oxide and titanium oxide.
This paper aims to investigate the water saturation effects on the thermal infrared radiation (IRR) characteristics of rock materials during deformation and fracturing processes. Three kinds of ...rocks, namely sandstone, granite, and marble, were adopted for tests. Uniaxial compression tests were carried out on oven-dried and water-saturated rock samples. The evolution of IRR temperature on rock surface was monitored and recorded with the aid of an infrared thermographic camera. Test results show that the IRR temperature of saturated samples is apparently higher than that of dry ones subjected to the same axial stress. After water saturation, the heating rate in elastic deformation phase, the IRR temperature increment at peak stress, and the IRR temperature on the new-formed fracture surface have a significant growth compared to dry condition. These indicate that the presence of water facilitates the release of thermal energy. The sensitivities of the heating rates in elastic deformation phase to water saturation are very distinct for the three rocks. This is possibly resulted from the mineral composition of rock types, especially the proportion of calcite and swelling clay minerals. The IRR temperature increment at peak stress for rock not only depends on the moisture condition, but is also relevant to the uniaxial compressive strength.
Aggregation-induced emission (AIE) has, since its discovery, become a valuable tool in the field of nanoscience. AIEgenic molecules, which display highly stable fluorescence in an assembled state, ...have applications in various biomedical fields-including photodynamic therapy. Engineering structure-inherent, AIEgenic nanomaterials with motile properties is, however, still an unexplored frontier in the evolution of this potent technology. Here, we present phototactic/phototherapeutic nanomotors where biodegradable block copolymers decorated with AIE motifs can transduce radiant energy into motion and enhance thermophoretic motility driven by an asymmetric Au nanoshell. The hybrid nanomotors can harness two photon near-infrared radiation, triggering autonomous propulsion and simultaneous phototherapeutic generation of reactive oxygen species. The potential of these nanomotors to be applied in photodynamic therapy is demonstrated in vitro, where near-infrared light directed motion and reactive oxygen species induction synergistically enhance efficacy with a high level of spatial control.
Introduction
The complete surgical removal of endometriosis lesions is not always feasible because some implants may be very small or hidden. The use of intraoperative near‐infrared radiation (NIR) ...imaging after intravenous injection of indocyanine green (ICG) coupled with robotic technical advances, including three‐dimensional (3D) and high‐resolution vision, might improve detection rates.
Material and methods
This is a retrospective, multicenter case‐control study (Canadian Task Force classification II‐2) on medical records of women with endometriosis who underwent surgery at the Catholic University of Rome (Controls) and the University of Bologna (Cases) between January 2016 and March 2018. Surgical and post‐surgical data from the procedures were collected. We compared the visual detection rate of endometriotic lesions using near‐infrared radiation imaging after intravenous injection of indocyanine green (NIR‐ICG) in Real 3D (Cases) with the 2D Camera approach (Controls) in symptomatic women with pelvic endometriosis.
Results
Twenty cases were matched as closely as possible with 27 controls. The numbers of suspected lesions identified both with the white light and the NIR‐ICG approach were 116 and 70 in the Controls (2D) and Cases (3D), respectively. Among them, 16 of 116 controls (13.8%) and 12 of 70 cases (17.1%) were identified using only NIR‐ICG imaging and collected as occult lesions (P = .536). The overall NIR‐ICG lesion identification showed a positive predictive value of 97.8%, negative predictive value of 82.3%, sensitivity of 82.0%, and specificity of 97.9% for the Control group, and a positive predictive value of 100%, negative predictive value of 97.1%, sensitivity of 97.1%, and specificity of 100% for the Case group, confirming that NIR‐ICG imaging is a good diagnostic and screening test (P = .643 and P = .791, according to the Cohen κ tests, respectively for the laparoscopic and robotic groups).
Conclusions
The few differences observed did not seem to be clinically relevant, making the 2 procedures comparable in terms of the ability to visually detect endometriotic lesions. Further prospective trials are needed to confirm our results.
Abstract
We present 75 near-infrared (NIR; 0.8−2.5
μ
m) spectra of 34 stripped-envelope core-collapse supernovae (SESNe) obtained by the Carnegie Supernova Project-II (CSP-II), encompassing optical ...spectroscopic Types IIb, Ib, Ic, and Ic-BL. The spectra range in phase from pre-maximum to 80 days past maximum. This unique data set constitutes the largest NIR spectroscopic sample of SESNe to date. NIR spectroscopy provides observables with additional information that is not available in the optical. Specifically, the NIR contains the strong lines of He
i
and allows a more detailed look at whether Type Ic supernovae are completely stripped of their outer He layer. The NIR spectra of SESNe have broad similarities, but closer examination through statistical means reveals a strong dichotomy between NIR “He-rich” and “He-poor” SNe. These NIR subgroups correspond almost perfectly to the optical IIb/Ib and Ic/Ic-BL types, respectively. The largest difference between the two groups is observed in the 2
μ
m region, near the He
i
λ
2.0581
μ
m line. The division between the two groups is
not
an arbitrary one along a continuous sequence. Early spectra of He-rich SESNe show much stronger He
i
λ
2.0581
μ
m absorption compared to the He-poor group, but with a wide range of profile shapes. The same line also provides evidence for trace amounts of He in half of our SNe in the He-poor group.
ABSTRACT We present key results from the Herschel Orion Protostar Survey: spectral energy distributions (SEDs) and model fits of 330 young stellar objects, predominantly protostars, in the Orion ...molecular clouds. This is the largest sample of protostars studied in a single, nearby star formation complex. With near-infrared photometry from 2MASS, mid- and far-infrared data from Spitzer and Herschel, and submillimeter photometry from APEX, our SEDs cover 1.2-870 m and sample the peak of the protostellar envelope emission at ∼100 m. Using mid-IR spectral indices and bolometric temperatures, we classify our sample into 92 Class 0 protostars, 125 Class I protostars, 102 flat-spectrum sources, and 11 Class II pre-main-sequence stars. We implement a simple protostellar model (including a disk in an infalling envelope with outflow cavities) to generate a grid of 30,400 model SEDs and use it to determine the best-fit model parameters for each protostar. We argue that far-IR data are essential for accurate constraints on protostellar envelope properties. We find that most protostars, and in particular the flat-spectrum sources, are well fit. The median envelope density and median inclination angle decrease from Class 0 to Class I to flat-spectrum protostars, despite the broad range in best-fit parameters in each of the three categories. We also discuss degeneracies in our model parameters. Our results confirm that the different protostellar classes generally correspond to an evolutionary sequence with a decreasing envelope infall rate, but the inclination angle also plays a role in the appearance, and thus interpretation, of the SEDs.
We analyze the >4 sources in the most sensitive 100 arcmin2 area (rms < 0.56 mJy) of a SCUBA-2 850 m survey of the GOODS-S and present the 75 band-7 ALMA sources (>4.5 ) obtained from high-resolution ...interferometric follow-up observations. The raw SCUBA-2 >4 limit is fainter than 2.25 mJy throughout this region, and deboosting corrections would lower this further. Of the 53 SCUBA-2 sources in this sample, only five have no ALMA detections, while 13% (68% confidence range 7%-19%) have multiple ALMA counterparts. Color-based high-redshift dusty galaxy selection techniques find at most 55% of the total ALMA sample. In addition to using literature spectroscopic and optical/near-infrared photometric redshifts, we estimate far infrared photometric redshifts based on an Arp 220 template. We identify seven z 4 candidates. We see the expected decline with redshift of the 4.5 and 24 m to 850 m flux ratios, confirming these as good diagnostics of z 4 candidates. We visually classify 52 ALMA sources, finding 44% (68% confidence range 35%-53%) to be apparent mergers. We calculate rest-frame 2-8 keV and 8-28 keV luminosities using the 7 Ms Chandra X-ray image. Nearly all of the ALMA sources detected at 0.5-2 keV are consistent with a known X-ray luminosity to 850 m flux relation for star-forming galaxies, while most of those detected at 2-7 keV are moderate-luminosity AGNs that lie just above the 2-7 keV detection threshold. The latter largely have substantial obscurations of cm−2, but two of the high-redshift candidates may even be Compton thick.
Polar topological texture has become an emerging research field for exotic phenomena and potential applications in reconfigurable electronic devices. We report toroidal topological texture ...self-organized in a ferroelectric polymer, poly(vinylidene fluoride-
-trifluoroethylene) P(VDF-TrFE), that exhibits concentric topology with anticoupled chiral domains. The interplay among the elastic, electric, and gradient energies results in continuous rotation and toroidal assembly of the polarization perpendicular to polymer chains, whereas relaxor behavior is induced along polymer chains. Such toroidal polar topology gives rise to periodic absorption of polarized far-infrared (FIR) waves, enabling the manipulation of the terahertz wave on a mesoscopic scale. Our observations should inform design principles for flexible ferroic materials toward complex topologies and provide opportunities for multistimuli conversions in flexible electronics.
Phytochrome photoreceptors absorb far-red and near-infrared (NIR) light and regulate light responses in plants, fungi, and bacteria. Their multidomain structure and autocatalytic incorporation of ...linear tetrapyrrole chromophores make phytochromes attractive molecular templates for the development of light-sensing probes. A subclass of bacterial phytochromes (BphPs) utilizes heme-derived biliverdin tetrapyrrole, which is ubiquitous in mammalian tissues, as a chromophore. Because biliverdin possesses the largest electron-conjugated chromophore system among linear tetrapyrroles, BphPs exhibit the most NIR-shifted spectra that reside within the NIR tissue transparency window. Here we analyze phytochrome structure and photochemistry to describe the molecular mechanisms by which they function. We then present strategies to engineer BphP-based NIR fluorescent proteins and review their properties and applications in modern imaging technologies. We next summarize designs of reporters and biosensors and describe their use in the detection of protein–protein interactions, proteolytic activities, and posttranslational modifications. Finally, we provide an overview of optogenetic tools developed from phytochromes and describe their use in light-controlled cell signaling, gene expression, and protein localization. Our review provides guidelines for the selection of NIR probes and tools for noninvasive imaging, sensing, and light-manipulation applications, specifically focusing on probes developed for use in mammalian cells and in vivo.
PDF
