CoMnOx Nanoflower-Based Smartphone Sensing Platform and Virtual Reality Display for Colorimetric Detection of Ziram and Cu2.

Transition metal doping is an ideal strategy to construct multifunctional and efficient nanozymes for biosensing. In this work, a metal-doped CoMnOx nanozyme was designed and synthesized by hydrothermal reaction and high-temperature calcination. Based on its oxidase activity, an "on-off-on" smartphone sensing platform was established to detect ziram and Cu2+. The obtained flower-shaped CoMnOx could exhibit oxidase-, catalase-, and laccase-like activities. The oxidase activity mechanism of CoMnOx was deeply explored. O2 molecules adsorbed on the surface of CoMnOx were activated to produce a large amount of O2·-, and then, O2·- could extract acidic hydrogen from TMB to produce blue oxTMB. Meanwhile, TMB was oxidized directly to the blue product oxTMB via the high redox ability of Co species. According to the excellent oxidase-like activity of CoMnOx, a versatile colorimetric detection platform for ziram and Cu2+ was successfully constructed. The linear detection ranges for ziram and Cu2+ were 5~280 µM and 80~360 µM, and the detection limits were 1.475 µM and 3.906 µM, respectively. In addition, a portable smartphone platform for ziram and Cu2+ sensing was established for instant analysis, showing great application promise in the detection of real samples including environmental soil and water.

Case report: Treatment of two cases of recurrent/refractory early T-cell precursor acute lymphoblastic leukemia with venetoclax combined with the CAG regimen.

Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) is a highly aggressive subtype of T-ALL. No standard chemotherapy regimen exists for patients with recurrent/refractory (R/R) ETP-ALL; in these patients, the primary goal of salvage therapy is to achieve remission as a foundation for consolidation and intensification treatments. This study reports cases of two patients with R/R ETP-ALL who underwent salvage therapy of venetoclax combined with the CAG regimen and achieved complete remission in the bone marrow. Flow cytometry results were negative for minimal residual disease. Both patients were bridged to allogeneic hematopoietic stem cell transplantation (HSCT) and in complete remission over a 3-year follow-up period. These cases show that the use of venetoclax combined with the CAG regimen may offer patients with R/R ETP-ALL an opportunity for allogeneic HSCT.

Systemic and Local Administration of a Dual-siRNA Complex Efficiently Inhibits Tumor Growth and Bone Invasion in Oral Squamous Cell Carcinoma.

Oral squamous cell carcinoma (OSCC) accounts for nearly 90% of oral and oropharyngeal cancer cases and is characterized by high mortality and poor prognosis. RNA-based gene therapies have been developed as an emerging option for cancer treatment, but it has not been widely explored in OSCC. In this work, we developed an efficient siRNA cationic micelle DOTAP-mPEG-PCL (DMP) by self-assembling the cationic lipid DOTAP and monomethoxy poly(ethylene glycol)-poly(ε-caprolactone) (mPEG-PCL) polymer. We tested the characteristics and transformation efficiency of this micelle and combined DMP with siRNA targeting STAT3 and TGF-ß to evaluate the antitumor effect and bone invasion interfering in vitro and in vivo. The average size of the DMP was 28.27 ± 1.62 nm with an average zeta potential of 54.60 ± 0.29 mV. The DMP/siRNA complex showed high delivery efficiency, with rates of 97.47 ± 0.42% for HSC-3. In vitro, the DMP/siSTAT3 complex exhibited an obvious cell growth inhibition effect detected by MTT assay (an average cell viability of 25.1%) and clonogenic assay (an average inhibition rate of 51.9%). Besides, the supernatant from HSC-3 transfected by DMP/siTGF-ß complexes was found to interfere with osteoclast differentiation in vitro. Irrespective of local or systemic administration, DMP/siSTAT3+siTGF-ß showed antitumor effects and bone invasion inhibition in the OSCC mice mandibular invasion model according to tumor volume assays and Micro-CT scanning. The complex constructed by DMP cationic micelles and siSTAT3+siTGF-ß represents a potential RNA-based gene therapy delivery system for OSCC.

Construction of CuO/Fe2O3 Nanozymes for Intelligent Detection of Glufosinate and Chlortetracycline Hydrochloride.

In this work, CuO/Fe2O3 nanozymes with high peroxidase-like activity were synthesized by using hydrothermal and calcination methods. The high-resolution transmission electron microscopy (HRTEM) proved that the heterogeneous interface of CuO/Fe2O3 was the main reason for the high enzyme-like activity. Strong interactions of CuO and Fe2O3 were successfully verified by X-ray absorption near-edge structure (XANES) characterization. Experiments and density functional theory (DFT) calculations were also used to explain the increased enzyme activity. The heterogeneous interface acted as the main active center, facilitating the electron transfer from CuO to Fe2O3. A colorimetric and intelligent sensing system was constructed based on deep learning. Using the peroxidase-like activity of CuO/Fe2O3, a platform for glufosinate pesticides and chlortetracycline hydrochloride (CTC) with the signal "on-off-on" changes were established. The limit of detection (LOD) of glufosinate and CTC was 28 and 0.69 µM, respectively. It was successfully applied in the detection of environmental water and soil. This study can provide an intelligent detection method for environmental monitoring.

Treatment of Ulcerative Colitis by Cationic Liposome Delivered NLRP3 siRNA.

Purpose: The abnormal activation of NLRP3 inflammasome is related to the occurrence and development of ulcerative colitis (UC). However, the ideal drug and delivery system remain important factors limiting the targeting of NLRP3 inflammasome in UC therapy. Gene therapy by delivering siRNA is effective in treating various diseases. Therefore, delivering siNLRP3 using an ideal vector for UC treatment is necessary. Materials and Methods: Nanoparticles delivering siNLRP3 were developed based on cationic liposome (CLP/siNLRP3). Their ability to inhibit NLRP3 inflammasome activation was monitored using Western blot (WB) and Enzyme-linked Immunosorbent Assay (ELISA). The ASC oligomerization in LPS-primed peritoneal macrophages (PMs) was detected by WB and immunofluorescence. Moreover, we assessed the role of CLP/siNLRP3 on dextran sodium sulfate (DSS)-induced UC by examining NLRP3 levels, pro-inflammatory cytokines expression, and disease-associated index (DAI). Flow cytometry (FCM) was used to detect the contents of macrophages and T cells. Finally, we assessed the safety of CLP/siNLRP3. Results: The prepared CLP was spherical, with a small particle size (94 nm) and low permeability. The CLP could efficiently protect siNLRP3 from degradation and then deliver siNLRP3 into PMs, inhibiting NLRP3 inflammasome activation. Also, the CLP/siNLRP3 could inhibit the secretion of mature IL-1ß and IL-18 from PMs, thereby achieving a favorable anti-inflammation effect. In vivo, CLP/siNLRP3 could effectively alleviate intestinal injury in UC mice, which was attributed to down-regulating levels of IL-1ß and IL-18, inhibiting infiltration of macrophages and other immune cells, and the polarization of M1 macrophages. Finally, pathological testing of tissue sections and blood biochemical tests showed no significant toxic effects of CLP/siNLRP3. Conclusion: We introduced a prospective approach for the efficient delivery of siRNA in vitro and in vivo with high safety and stability, which was found to have great potential in treating NLRP3-driven diseases in an RNA-silencing manner.

Incorporating marine particulate carbon into machine learning for accurate estimation of coastal chlorophyll-a.

Accurate predictions of coastal ocean chlorophyll-a (Chl-a) concentrations are necessary for dynamic water quality monitoring, with eutrophication as a critical factor. Prior studies that used the driven-data method have typically overlooked the relationship between Chl-a and marine particulate carbon. To address this gap, marine particulate carbon was incorporated into machine learning (ML) and deep learning (DL) models to estimate Chl-a concentrations in the Yang Jiang coastal ocean of China. Incorporating particulate organic carbon (POC) and particulate inorganic carbon (PIC) as predictors can lead to successful Chl-a estimation. The Gaussian process regression (GPR) model significantly outperforming the DL model in terms of stability and robustness. A lower POC/Chl-a ratio was observed in coastal areas, in contrast to the higher ratios detected in the southern regions of the study area. This study highlights the efficacy of the GPR model for estimating Chl-a and the importance of considering POC in modeling Chl-a concentrations.

Effects of Terahertz Radiation on the Aggregation of Alzheimer's Aß42 Peptide.

The pathophysiology of Alzheimer's disease is thought to be directly linked to the abnormal aggregation of ß-amyloid (Aß) in the nervous system as a common neurodegenerative disease. Consequently, researchers in many areas are actively looking for factors that affect Aß aggregation. Numerous investigations have demonstrated that, in addition to chemical induction of Aß aggregation, electromagnetic radiation may also affect Aß aggregation. Terahertz waves are an emerging form of non-ionizing radiation that has the potential to affect the secondary bonding networks of biological systems, which in turn could affect the course of biochemical reactions by altering the conformation of biological macromolecules. As the primary radiation target in this investigation, the in vitro modeled Aß42 aggregation system was examined using fluorescence spectrophotometry, supplemented by cellular simulations and transmission electron microscopy, to see how it responded to 3.1 THz radiation in various aggregation phases. The results demonstrated that in the nucleation aggregation stage, 3.1 THz electromagnetic waves promote Aß42 monomer aggregation and that this promoting effect gradually diminishes with the exacerbation of the degree of aggregation. However, by the stage of oligomer aggregation into the original fiber, 3.1 THz electromagnetic waves exhibited an inhibitory effect. This leads us to the conclusion that terahertz radiation has an impact on the stability of the Aß42 secondary structure, which in turn affects how Aß42 molecules are recognized during the aggregation process and causes a seemingly aberrant biochemical response. Molecular dynamics simulation was employed to support the theory based on the aforementioned experimental observations and inferences.

The collective vibrational modes of dihydropyridine in nifedipine studied by terahertz spectroscopy.

Cardiovascular pharmaceuticals have drawn huge attention in drug development. Nifedipine (NFD) is an important member of calcium channel blockers (CCB) with the structural characteristic of dihydropyridine (DHP), but the binding mechanism to its target remains an open question. Even though several analytical techniques have been used for structural characterizations, the information of collective vibrational behavior is still lacking. In this work, we use terahertz (THz) spectroscopy to investigate the spectral fingerprints of NFD, and quantitatively evaluate the temperature-induced frequency shifts. Combined with quantum chemical calculations, each THz fingerprint is attributed to specific collective vibrational modes. The collective vibrations of DHP are mainly distributed below 2.5 THz, which provides complementary information to understand the behavior of rigid DHP ring. The rotation of methyl group and the wagging of nitrophenyl group are widely distributed in the range of 1.0-4.0 THz, which is helpful for the conformational recognition between NFD and target molecule. THz spectroscopy is demonstrated to be suitable for characterizing the collective vibrational modes of DHP and elucidating the drug-target binding behavior from the perspective of noncovalent interactions. It has the potential to become a non-invasive technology for conformational analysis and pharmaceutical development.

Co3O4/CoFe2O4 Hollow Nanocube Multifunctional Nanozyme with Oxygen Vacancies for Deep-Learning-Assisted Smartphone Biosensing and Organic Pollutant Degradation.

Although the application of nanozymes has been widely studied, it is still a huge challenge to develop highly active and multifunctional nanozyme catalysts with a wider application prospect. Co3O4/CoFe2O4 hollow nanocubes (HNCs) with oxygen vacancies were proposed in this study, which had a porous oxide heterostructure with CoFe2O4 as the core and Co3O4 as the shell. The Co3O4/CoFe2O4 HNCs had three enzyme activities: peroxidase-like, oxidase-like, and catalase-like. Combining XPS depth profiling with density functional theory (DFT), the catalytic mechanism of peroxidase-like activity was explored in depth, which was mainly originated from ·OH produced by the synergistic effect between the outer oxygen and inner oxygen and electron transfer between Co and Fe. A colorimetry/smartphone dual sensing platform was designed based on the peroxidase-like activity. Especially, a multifunctional intelligent sensing platform based on deep learning-YOLO v3 algorithm-assisted smartphone was constructed to realize real-time and rapid in situ detection of l-cysteine, norfloxacin, and zearalenone. Surprisingly, the detection limit of norfloxacin was low at 0.015 µM, which was better than that of the newly published detection method in the field of nanozymes. Meanwhile, the detection mechanism of l-cysteine and norfloxacin was successfully investigated by in situ FTIR. In fact, it also showed outstanding applications in detecting l-cysteine in the food environment and norfloxacin in drugs. Furthermore, Co3O4/CoFe2O4 HNCs also could degrade 99.24% of rhodamine B, along with good reusability even after 10-cycle runs. Therefore, this work provided an in-depth understanding of the synergistic effect between the outer and inner oxygen in the reaction mechanism and an efficient method for establishing a deep-learning-assisted intelligent detection platform. In addition, this research also offered a good guideline for the further development and construction of nanozyme catalysts with multienzyme activities and multifunctional applications.

Peptidyl Virus-Like Nanovesicles as Reconfigurable "Trojan Horse" for Targeted siRNA Delivery and Synergistic Inhibition of Cancer Cells.

The self-assembly of peptidyl virus-like nanovesicles (pVLNs) composed of highly ordered peptide bilayer membranes that encapsulate the small interfering RNA (siRNA) is reported. The targeting and enzyme-responsive sequences on the bilayer's surface allow the pVLNs to enter cancer cells with high efficiency and control the release of genetic drugs in response to the subcellular environment. By transforming its structure in response to the highly expressed enzyme matrix metalloproteinase 7 (MMP-7) in cancer cells, it helps the siRNA escape from the lysosomes, resulting in a final silencing efficiency of 92%. Moreover, the pVLNs can serve as reconfigurable "Trojan horse" by transforming into membranes triggered by the MMP-7 and disrupting the cytoplasmic structure, thereby achieving synergistic anticancer effects and 96% cancer cell mortality with little damage to normal cells. The pVLNs benefit from their biocompatibility, targeting, and enzyme responsiveness, making them a promising platform for gene therapy and anticancer therapy.

Case Report: Neuromyelitis Optica Spectrum Disorder With Progressive Elevation of Cerebrospinal Fluid Cell Count and Protein Level Mimicking Infectious Meningomyelitis: A Diagnostic Challenge.

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune-mediated idiopathic inflammatory demyelinating disease with a typical clinical presentation of optic neuritis, acute myelitis, and area postrema syndrome. Most NMOSD patients are seropositive for disease-specific and pathogenic aquaporin-4 (AQP4) antibodies, which are key markers for the NMOSD diagnosis. Herein, we report an atypical case of a 41-year-old man who complained of intractable hiccups and vomiting at disease onset, followed by fever, headache, back pain, progressive paresthesia, and weakness of extremities later on. Magnetic resonance imaging revealed longitudinally extensive transverse myelitis. Cerebrospinal fluid analysis showed progressive increases in the white blood cell count and the protein level, which were accompanied by the deterioration of clinical manifestations. The patient was initially suspected of infectious meningomyelitis but was finally diagnosed with NMOSD. This case with distinct cerebrospinal fluid findings broadens the phenotypic spectrum of NMOSD. Furthermore, it also highlights the clinical value of AQP4 antibody test for early definitive diagnosis and proper treatment.

Engineering an oilseed crop for hyper-accumulation of carotenoids in the seeds without using a traditional marker gene.

KEY MESSAGE: Ketocarotenoids were synthesized successfully in Camelina sativa seeds by genetic modification without using a traditional selection marker genes. This method provided an interesting tool for metabolic engineering of seed crops. Camelina sativa (L.) Crantz is an important oil crop with many excellent agronomic traits. This model oil plant has been exploited to accumulate value-added bioproducts using genetic manipulation that depends on antibiotic- or herbicide-based selection marker genes (SMG), one of the major concerns for genetically modified foods. Here we reported metabolic engineering of C. sativa to synthesize red ketocarotenoids that could serve as a reporter to visualize transgenic events without using a traditional SMG. Overexpression of a non-native ß-carotene ketolase gene coupled with three other carotenogenous genes (phytoene synthase, ß-carotene hydroxylase, and Orange) in C. sativa resulted in production of red seeds that were visibly distinguishable from the normal yellow ones. Constitutive expression of the transgenes led to delayed plant development and seed germination. In contrast, seed-specific transformants demonstrated normal growth and seed germination despite the accumulation of up to 70-fold the level of carotenoids in the seeds compared to the controls, including significant amounts of astaxanthin and keto-lutein. As a result, the transgenic seed oils exhibited much higher antioxidant activity. No significant changes were found in the profiles of fatty acids between transgenic and control seeds. This study provided an interesting tool for metabolic engineering of seed crops without using a disputed SMG.

The fingerprints of nifedipine/isonicotinamide cocrystal polymorph studied by terahertz time-domain spectroscopy.

Cocrystal is constructed to improve physicochemical properties of active pharmaceutical ingredient and prevent polymorphism via intermolecular interactions. However, recent examples on cocrystal polymorphs display significantly different properties. Even though some analytical techniques have been used to characterize the cocrystal polymorphic system, it remains unclear how intermolecular interactions drive and stabilize the structure. In this work, we study the cocrystal polymorphs of nifedipine (NFD) and isonicotinamide (INA) using terahertz (THz) spectroscopy. Form I and form II of NFD-INA cocrystals show spectral fingerprints in THz region. Temperature-dependent THz spectra display distinguished frequency shifts of each fingerprint. Combined with solid-state density functional theory (DFT) calculations, the experimental fingerprints and their distinct responses to temperature are elucidated by specific collective vibrational modes. The vibrations of hydrogen bonding between dihydropyridine ring of NFD and INA are generally distributed below 1.5 THz, which play important roles in stabilizing cocrystal and preventing the oxidation of NFD. The rotations of methyl group in NFD are widely distributed in the range of 1.5-4.0 THz, which helps the steric recognition. The results demonstrate that THz spectroscopy is a sensitive tool to discriminate cocrystal polymorphs. It has the potential to be used as a non-invasive technique for pharmaceutical screening.

[Hydrochemical Characteristics and Analysis of the Qilihai Wetland, Tianjin].

Hydrochemistry is an important parameter for wetland water environmental assessment. To study the hydrochemistry and main ion sources in the Qilihai wetland in Tianjin, river water, groundwater, and water in the marsh were collected and analyzed. The results show that:① The river and marsh waters are SO4·Cl-Na in type and groundwater water is HCO3-Na and HCO3-Na·Ca in type. The water in the marshes is mainly recharged by river water and the exchange of shallow groundwater with river water is notable; ② Precipitation has little effect on the chemical composition of the water. Na+ and K+ were derived from the dissolution of salt rock and evaporative concentration. Ca2+, Mg2+, and HCO3- in the river and marsh water are mainly derived from the dissolution of evaporite salt rock. Ca2+, Mg2+, and HCO3- in the groundwater are mainly derived from carbonate mineral dissolution; ③ The hydrochemical composition of the river water and groundwater is notably affected by ion exchange, but this was not observed in the marsh water. Furthermore, SO42- and NO3- are affected by human activity. During the dry season, the river and marsh water are affected by evaporite salt rock dissolution, evaporation, and human effects, while in wet season, river water is mainly affected by carbonate dissolution and human activities. These observations demonstrate how that hydrochemical composition of this wetland is controlled by a combination of natural factors and human activities.

Self-Assembled Bio-Organometallic Nanocatalysts for Highly Enantioselective Direct Aldol Reactions.

Supramolecular nanocatalysts were designed for asymmetric reactions through the self-assembly process of a bio-organometallic molecule, ferrocene-l-prolinamide (Fc-CO-NH-P). Fc-CO-NH-P could self-assemble into versatile nanostructures in water, including nanospheres, nanosheets, nanoflowers, and pieces. In particular, the self-assembled nanoflowers exhibited a superior specific surface area, high stability, and delicate three-dimensional (3D) chiral catalytic active sites. The nanoflowers could serve as heterogeneous catalysts with an excellent catalytic performance toward direct aldol reactions in aqueous solution, achieving both high yield (>99%) and stereoselectivity (anti/syn = 97:3, ee% >99%). This study proposed a significant strategy to fabricate supramolecular chiral catalysts, serving as a favorable template for designing new asymmetric catalysts.

Relationship between the honeydew of mealy bugs and the growth of Phlebopus portentosus.

BACKGROUND: Phlebopus portentosus and mealy bugs form a fungus-insect gall on the roots of host plants. The fungus and mealy bugs benefit mutually through the gall, which is the key link in the nutritional mechanism of P. portentosus. The cavity of the fungus-insect gall provides an ideal shelter for mealy bugs survival and reproduction, but how does P. portentosus benefit from this symbiotic relationship? METHODOLOGY AND RESULTS: Anatomical examination of fungus-insect galls revealed that one or more mealy bugs of different generations were living inside the galls. The mealy bug's mouthpart could penetrate through the mycelium layer of the inside of the gall and suck plant juice from the host plant root. Mealy bugs excreted honeydew inside or outside the galls. The results of both honeydew agar medium and quartz tests showed that the honeydew can attract and promote the mycelial growth of P. portentosus. A test of the relationship between the honeydew and the formation of the fungus-insect gall showed that honeydew promoted gall formation. CONCLUSIONS: All experimental results in this study show that the honeydew secreted by mealy bugs can attract and promote the mycelial growth of P. portentosus, forming a fungus-insect gall, because mealy bugs' honeydew is rich in amino acids and sugars.

Variability of relationship between the volume scattering function at 180° and the backscattering coefficient for aquatic particles.

Properly interpreting lidar (light detection and ranging) signal for characterizing particle distribution relies on a key parameter, χp(π), which relates the particulate volume scattering function (VSF) at 180° (ßp(π)) that a lidar measures to the particulate backscattering coefficient (bbp). However, χp(π) has been seldom studied due to challenges in accurately measuring ßp(π) and bbp concurrently in the field. In this study, χp(π), as well as its spectral dependence, was re-examined using the VSFs measured in situ at high angular resolution in a wide range of waters. ßp(π), while not measured directly, was inferred using a physically sound, well-validated VSF-inversion method. The effects of particle shape and internal structure on the inversion were tested using three inversion kernels consisting of phase functions computed for particles that are assumed as homogenous sphere, homogenous asymmetric hexahedra, or coated sphere. The reconstructed VSFs using any of the three kernels agreed well with the measured VSFs with a mean percentage difference <5% at scattering angles <170∘. At angles immediately near or equal to 180°, the reconstructed ßp(π) depends strongly on the inversion kernel. χp(π) derived with the sphere kernels was smaller than those derived with the hexahedra kernel but consistent with χp(π) estimated directly from high-spectral-resolution lidar and in situ backscattering sensor. The possible explanation was that the sphere kernels are able to capture the backscattering enhancement feature near 180° that has been observed for marine particles. χp(π) derived using the coated sphere kernel was generally lower than those derived with the homogenous sphere kernel. Our result suggests that χp(π) is sensitive to the shape and internal structure of particles and significant error could be induced if a fixed value of χp(π) is to be used to interpret lidar signal collected in different waters. On the other hand, χp(π) showed little spectral dependence.

Heterologous expression of HpBHY and CrBKT increases heat tolerance in Physcomitrella patens.

Heat stress can restrict plant growth, development, and crop yield. As essential plant antioxidants, carotenoids play significant roles in plant stress resistance. ß-carotene hydroxylase (BHY) and ß-carotene ketolase (BKT), which catalyze the conversions of ß-carotene to zeaxanthin and ß-carotene to canthaxanthin, respectively, are key enzymes in the carotenoid biosynthetic pathway, but little is known about their potential functions in stress resistance. Here, we investigated the roles of ß-carotene hydroxylase and ß-carotene ketolase during heat stress in Physcomitrella patens through expressing a ß-carotene ketolase gene from Chlamydomonas reinhardtii (CrBKT) and a ß-carotene hydroxylase gene from Haematococcus pluvialis (HpBHY) in the moss P. patens. In transgenic moss expressing these genes, carotenoids content increased (especially lutein content), and heat stress tolerance increased, with reduced leafy tissue necrosis. To investigate the mechanism of this heat stress resistance, we measured various physiological indicators and found a lower malondialdehyde level, higher peroxidase and superoxide dismutase activities, and higher endogenous abscisic acid and salicylate content in the transgenic plants in response to high-temperature stress. These results demonstrate that CrBKT and HpBHY increase plant heat stress resistance through the antioxidant and damage repair metabolism, which is related to abscisic acid and salicylate signaling.

Ultra-broadband microwave metamaterial absorber with tetramethylurea inclusion.

The absorption region of a water-based absorber was expanded by introducing tetramethylurea (TMU) into the inclusion, whose dielectric properties are tunable through the concentration of TMU. The dielectric spectroscopy of a TMU/water mixture was deconstructed using a Debye model. We designed a four-layer ultra-broadband microwave absorber with a supernatant micro-structure. Simulation and experiment results indicate that the absorber can achieve 90% perfect absorption, covering a broad frequency range of 4-40 GHz. The concentration dependence of the absorber was also studied experimentally and numerically. The concentration control provides a more practical and large frequency-region modulation of perfect absorption.

Calibration of the LISST-VSF to derive the volume scattering functions in clear waters.

The recently commercialized LISST-VSF instrument measures the volume scattering function (VSF) from 0.1° to 15° with a traditional laser diffraction unit (LISST) and from 15° to 155° with an eyeball component. Between these two optical components, only the LISST unit is calibrated. The eyeball measurements are scaled using the VSFs at 15° that are measured by both components. As this relative calibration relies on a valid measurement at 15° by the LISST, it might fail in clear oceanic waters, where the forward scattering is relative weak either due to a lack of large particles or an overall low concentration of all particles. In this study, we calibrated the LISST-VSF eyeball component through a series of lab experiments using standard polystyrene beads. Validation with the beads of two different sizes showed a median difference of 11.1% between theoretical and calibrated values. Further evaluations with in situ data collected by the LISST-VSF and an ECO-BB3 meter indicated that the new calibration worked well in both turbid and clear waters, while the relative calibration method tended to overestimate VSFs in clear waters.