Chang'E-4 initial spectroscopic identification of lunar far-side mantle-derived materials.

Over 60 years of spacecraft exploration has revealed that the Earth's Moon is characterized by a lunar crust1 dominated by the mineral plagioclase, overlying a more mafic (richer in iron and magnesium) mantle of uncertain composition. Both crust and mantle formed during the earliest stages of lunar evolution when late-stage accretional energy caused a molten rock (magma) ocean, flotation of the light plagioclase, sinking of the denser iron-rich minerals, such as olivine and pyroxene, and eventually solidification2. Very large impact craters can potentially penetrate through the crust and sample the lunar mantle. The largest of these craters is the approximately 2,500-kilometre-diameter South Pole-Aitken (SPA) basin3 on the lunar far side. Evidence obtained from orbiting spacecraft shows that the floor of the SPA basin is rich in mafic minerals4, but their mantle origin is controversial and their in situ geologic settings are poorly known. China's Chang'E-4 lunar far-side lander recently touched down in the Von Kármán crater5,6 to explore the floor of the huge SPA basin and deployed its rover, Yutu-2. Here we report on the initial spectral observations of the Visible and Near Infrared Spectrometer (VNIS)7 onboard Yutu-2, which we interpret to represent the presence of low-calcium (ortho)pyroxene and olivine, materials that may originate from the lunar mantle. Geological context6 suggests that these materials were excavated from below the SPA floor by the nearby 72-km-diameter Finsen impact crater event, and transported to the landing site. Continued exploration by Yutu-2 will target these materials on the floor of the Von Kármán crater to understand their geologic context, origin and abundance, and to assess the possibility of sample-return scenarios.

Dispersion-Selective Band Engineering in an Artificial Kagome Superlattice.

The relentless pursuit of band structure engineering continues to be a fundamental aspect in solid-state research. Here, we meticulously construct an artificial kagome potential to generate and control multiple Dirac bands of graphene. This unique high-order potential harbors natural multiperiodic components, enabling the reconstruction of band structures through different potential contributions. As a result, the band components, each characterized by distinct dispersions, shift in energy at different velocities in response to the variation of artificial potential. Thereby, we observe a significant spectral weight redistribution of the multiple Dirac peaks. Furthermore, the magnetic field can effectively weaken the superlattice effect and reactivate the intrinsic Dirac band. Overall, we achieve actively dispersion-selective band engineering, a functionality that would substantially increase the freedom in band design.

Fabrication of composite hydrogels by sonication-assisted assembly of okara cellulose nanofibers and chitosan: structure and properties.

BACKGROUND: Okara cellulose is a highly abundant, green, sustainable, and biodegradable polymer with many potential industrial applications. In this study, we fabricated composite hydrogels with okara cellulose nanofibers (CNFs) and chitosan (CH) by hydrating, sonicating, and heating them at 100 °C for 30 min, and then induced their assembly by cooling. The effects of okara CNF (with and without 2,2,6,6-tetramethylpiperidinyloxy (TEMPO) oxidation) and CH concentration on the structure and properties of the hydrogels was examined, including their microstructure, surface properties, rheological properties, and thermal stability. RESULTS: Our results indicate that there was an electrostatic attraction between the anionic okara CNF and cationic CH, which facilitated hydrogel formation. The surface, textural, rheological, and thermal stability properties were better for the composite hydrogels than for the single CH ones, as well as for the CNF that had undergone TEMPO oxidation. For the TC-CH hydrogels, the contact angle was 39.5°, the interfacial tension was 69.1 mN m-1 , and the surface tension was 1.44 mN m-1 . CONCLUSION: In this study, the novel hydrogels developed may be useful as a soft material in a range of applications in foods, supplements, health care products, cosmetics, and drugs. © 2023 Society of Chemical Industry.

Screening of candidate genes related to differences in growth and development between Chinese indigenous and Western pig breeds.

Neijiang (NJ) and Yacha (YC) are two indigenous pig breeds in the Sichuan basin of China, displaying higher resistance to diseases, lower lean ratio, and slower growth rate than the commercial Western pig breed Yorkshire (YS). The molecular mechanisms underlying the differences in growth and development between these pig breeds are still unknown. In the present study, five pigs from NJ, YC, and YS breeds were subjected to the whole genome resequencing, and then the differential single-nucleotide polymorphisms (SNPs) were screened using a 10-kb window sliding in 1-kb step using the Fst method. Finally, 48,924, 48,543, and 46,228 nonsynonymous single-nucleotide polymorphism loci (nsSNPs) were identified between NJ and YS, NJ and YC, and YC and YS, which highly or moderately affected 2,490, 800, and 444 genes, respectively. Moreover, three nsSNPs were detected in the genes of acetyl-CoA acetyltransferase 1 (ACAT1) insulin-like growth factor 2 receptor (IGF2R), insulin-like growth factor 2 and mRNA-binding protein 3 (IGF2BP3), which potentially affected the transformation of acetyl-CoA to acetoacetyl-CoA and the normal functions of the insulin signaling pathways. Moreover, serous determinations revealed significantly lower acetyl-CoA content in YC than in YS, supporting that ACAT1 might be a reason explaining the differences in growth and development between YC and YS breeds. Contents of phosphatidylcholine (PC) and phosphatidic acid (PA) significantly differed between the pig breeds, suggesting that glycerophospholipid metabolism might be another reason for the differences between Chinese and Western pig breeds. Overall, these results might contribute basic information to understand the genetic differences determining the phenotypical traits in pigs.

Inter-/intra-pulse dual-wavelength-operated mid-infrared optical parametric oscillator.

We demonstrate a pulsed mid-infrared (MIR) optical parametric oscillator (OPO) with both inter-pulse and intra-pulse dual-wavelength operation capability. A fiber master oscillator power amplifier incorporating an acousto-optic tunable filter (AOTF) was employed as the pump for the OPO. By finely adjusting the drive wave packets for the AOTF, dual-wavelength pump can be realized within each pulse or between two adjacent pulses. These special temporal-spectral behaviors of the pump can be transferred to MIR via an OPO. In the proof-of-principle experiments, two pump wavelengths at ∼1065 and ∼1076 nm were generated and amplified to ∼31.2 W with equivalent spectral intensities for both pulsation modes. At the highest pump power, total idler power of ∼3.5 W was achieved at ∼3.45 and ∼3.55 µm under both pulsation modes. To the best of our knowledge, this is the first demonstration of both inter-pulse and intra-pulse dual-wavelength MIR generation via an OPO with an identical configuration. It is believed that our design may provide a promising solution to many practical applications including differential absorption lidar and tunable terahertz wave generation.

Ground-to-satellite quantum teleportation.

An arbitrary unknown quantum state cannot be measured precisely or replicated perfectly. However, quantum teleportation enables unknown quantum states to be transferred reliably from one object to another over long distances, without physical travelling of the object itself. Long-distance teleportation is a fundamental element of protocols such as large-scale quantum networks and distributed quantum computation. But the distances over which transmission was achieved in previous teleportation experiments, which used optical fibres and terrestrial free-space channels, were limited to about 100 kilometres, owing to the photon loss of these channels. To realize a global-scale 'quantum internet' the range of quantum teleportation needs to be greatly extended. A promising way of doing so involves using satellite platforms and space-based links, which can connect two remote points on Earth with greatly reduced channel loss because most of the propagation path of the photons is in empty space. Here we report quantum teleportation of independent single-photon qubits from a ground observatory to a low-Earth-orbit satellite, through an uplink channel, over distances of up to 1,400 kilometres. To optimize the efficiency of the link and to counter the atmospheric turbulence in the uplink, we use a compact ultra-bright source of entangled photons, a narrow beam divergence and high-bandwidth and high-accuracy acquiring, pointing and tracking. We demonstrate successful quantum teleportation of six input states in mutually unbiased bases with an average fidelity of 0.80 ± 0.01, well above the optimal state-estimation fidelity on a single copy of a qubit (the classical limit). Our demonstration of a ground-to-satellite uplink for reliable and ultra-long-distance quantum teleportation is an essential step towards a global-scale quantum internet.

Temperature and emissivity measurement algorithm using a moving emissivity retardation spectral window method based on Lagrange mean value theorem.

The multi-spectral radiation method is a non-contact technique that can measure the temperature and emissivity of an object. However, its core problem lies in solving the underdetermined equation system. Existing numerical emissivity methods require prior knowledge of emissivity, while emissivity function methods need accurate initial conditions. These approaches are not suitable for measuring unknown targets' temperature and emissivity. This paper proposes a moving emissivity retardation spectral window method that does not require any prior knowledge or initial conditions. The proposed method defines the emissivity retardation interval based on the Lagrange mean value theorem to provide universal and high-precision constraint conditions for solving the aforementioned underdetermined equation system. Simulation experiments were conducted on four target models with different emissivity, which showed that, compared to the moving narrowband window method, this new, to the best of our knowldge, approach reduced average temperature calculation errors by 31.0% and average emissivity calculation errors by 30.7%. In blackbody experiments, the calculated temperature error is about 0.4 K, and the emissivity is about 0.993-0.999. The described method is expected to meet the practical measurement needs for a wide range of substances.

Temporal microRNA expression profile of pig peripheral blood during postnatal development.

Gene expression profiles of blood can reflect the physiopathologic status of the immune system. The dynamic microRNA (miRNA) expression profiles of peripheral blood from pigs at different developmental stages, and how differential expression of miRNAs might relate to immune system development, are unknown. In this study, peripheral blood samples taken at five developmental stages were used to construct 15 miRNA libraries (three biological replicates/stage): 0 days (newborn), 30 days (weaning), 60 days (weaned), and 180 and 360 days (puberty). We identified 295 known mature miRNAs. Hierarchical clustering of the miRNA expression profile showed significant differences between individuals at the neonatal and postnatal stages. Functional enrichment analysis revealed that miRNAs differentially expressed between pairwise comparisons of the developmental stages were over-represented in immune-related pathways such as toll-like receptor signaling. The time-course of expression of the over-representated miRNAs exhibited a pattern of steady decline over time, for both the complete miRNA compendium and immune-related miRNAs. We identified six marker miRNAs that were highly negatively correlated with chronologic age and enriched for genes involved in immune-related pathways. This study of a peripheral blood miRNA transcriptome offers insight into immune system development in swine and provides a resource for pig genome annotation.

Current Non-Contact Road Surface Condition Detection Schemes and Technical Challenges.

Given the continuous improvement in the capabilities of road vehicles to detect obstacles, the road friction coefficient is closely related to vehicular braking control, thus the detection of road surface conditions (RSC), and the level is crucial for driving safety. Non-contact technology for RSC sensing is becoming the main technological and research hotspot for RSC detection because of its fast, non-destructive, efficient, and portable characteristics and attributes. This study started with mapping the relationship between friction coefficients and RSC based on the requirement for autonomous driving. We then compared and analysed the main methods and research application status of non-contact detection schemes. In particular, the use of infrared spectroscopy is expected to be the most approachable technology path to practicality in the field of autonomous driving RSC detection owing to its high accuracy and environmental adaptability properties. We systematically analysed the technical challenges in the practical application of infrared spectroscopy road surface detection, studied the causes, and discussed feasible solutions. Finally, the application prospects and development trends of RSC detection in the fields of automatic driving and exploration robotics are presented and discussed.

Radar Target Tracking for Unmanned Surface Vehicle Based on Square Root Sage-Husa Adaptive Robust Kalman Filter.

Dynamic information such as the position and velocity of the target detected by marine radar is frequently susceptible to external measurement white noise generated by the oscillations of an unmanned surface vehicle (USV) and target. Although the Sage-Husa adaptive Kalman filter (SHAKF) has been applied to the target tracking field, the precision and stability of SHAKF remain to be improved. In this paper, a square root Sage-Husa adaptive robust Kalman filter (SR-SHARKF) algorithm together with the constant jerk model is proposed, which can not only solve the problem of filtering divergence triggered by numerical rounding errors, inaccurate system mathematics, and noise statistical models, but also improve the filtering accuracy. First, a novel square root decomposition method is proposed in the SR-SHARKF algorithm for decomposing the covariance matrix of SHAKF to assure its non-negative definiteness. After that, a three-segment approach is adopted to balance the observed and predicted states by evaluating the adaptive scale factor. Finally, the unbiased and the biased noise estimators are integrated while the interval scope of the measurement noise is constrained to jointly evaluate the measurement and observation noise for better adaptability and reliability. Simulation and experimental results demonstrate the effectiveness of the proposed algorithm in eliminating white noise triggered by the USV and target oscillations.

Oxidative Stress Amelioration of Novel Peptides Extracted from Enzymatic Hydrolysates of Chinese Pecan Cake.

Pecan (Carya cathayensis) is an important economic crop, and its hydrolyzed peptides have been evidenced to reduce the effect of oxidative stress due to their antioxidant capacity. Hence, the protocols of ultrafiltration and gel filtration chromatography were established to obtain bioactive peptides from by-products of C. cathayensis (pecan cake). As measured by DPPH/ABTS radical scavenging, the peptides with less molecular weight (MW) possess higher antioxidant capacity. PCPH-III (MW < 3 kDa) presented higher radical scavenging capacity than PCPH-II (3 kDa < MW < 10 kDa) and PCPH-I (MW > 10 kDa) measured by DPPH (IC50: 111.0 µg/ mL) and measured by ABTs (IC50: 402.9 µg/mL). The secondary structure and amino acid composition varied by their MW, in which PCPH-II contained more α-helices (26.71%) and ß-sheets (36.96%), PCPH-III contained higher ratios of ß-turns (36.87%), while the composition of different secondary of PCPH-I was even 25 ± 5.76%. The variation trend of α-helix and random experienced slightly varied from PCPH-I to PCPH-II, while significantly decreased from PCPH-II to PCPH-III. The increasing antioxidant capacity is followed by the content of proline, and PCPH-III had the highest composition (8.03%). With regard to the six peptides identified by LC-MS/MS, two of them (VYGYADK and VLFSNY) showed stronger antioxidant capacity than others. In silico molecular docking demonstrated their combining abilities with a transcription factor Kelch-like ECH-associated protein 1 (Keap1) and speculated that they inhibit oxidative stress through activating the Keap1-Nrf2-ARE pathway. Meanwhile, increased activity of SOD and CAT­antioxidant markers­were found in H2O2-induced cells. The residue of tyrosine was demonstrated to contribute the most antioxidant capacity of VYGYADK and its position affected less. This study provided a novel peptide screening and by-product utilization process that can be applied in natural product developments.

Flexible wavelength generation from a Yb-doped fiber laser incorporating multifunctional acousto-optic tunable filter.

We have demonstrated a Yb-doped fiber laser (YDFL) based on a multifunctional acousto-optic tunable filter (AOTF) with flexible wavelength generation capability. The number of channels, as well as their diffracted wavelengths and corresponding peak transmittances of the AOTF, can be widely tuned by changing the composite drive signal from a homemade arbitrary wave generation (AWG) board enabling single-/multi-wavelength lasing with different central wavelengths and relative intensities. The maximal wavelength tuning range and minimal resolved wavelength spacing are ∼80nm and ∼1.5nm, respectively, with 3 dB bandwidth less than 0.15 nm for each laser line, showing great potential for further nonlinear frequency conversion. To the best of our knowledge, this is the first demonstration of flexible wavelength generation from a multifunctional AOTF-based YDFL directly driven by an AWG board.

Polarization-maintaining design for satellite-based quantum communication terminals.

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.

Concave aspheric test combining Dall with Offner null compensation using a plane wave.

A plane wave aspheric surfaces test is simpler and easier to assemble than a spherical wave test. An optical system combining Dall with Offner null compensation using a plane wave is proposed for measuring large-aperture and large-relative-aperture aspheric concave surfaces. One back compensation lens and one front compensation lens are used in the system, which can realize a high-precision null test. Based on the third-order aberration theory, the normalized theoretical parameters are calculated by formula derivation, and then are optimized after analysis. The design characteristic is compared with the classical plane wave Offner null test. A prototype experiment of the proposed method is carried out with a parabolic mirror of 500 mm diameter, at relative aperture 1/1, showing that RMS surface error of λ/40 can be obtained.

Temporal expression profiling of long noncoding RNA and mRNA in the peripheral blood during porcine development.

OBJECTIVE: We investigated the temporal expression profiles of long noncoding RNA (lncRNA) and mRNA in the peripheral blood of pigs during development and identified the lncRNAs that are related to the blood-based immune system. METHODS: Peripheral blood samples were obtained from the pigs at 0, 7, 28, and 180 days and 2 years of age. RNA sequencing was performed to survey the lncRNA and mRNA transcriptomes in the samples. Short time-series expression miner (STEM) was used to show temporal expression patterns in the mRNAs and lncRNAs. Gene ontology and Kyoto encyclopedia of genes and genomes analyses were performed to assess the genes' biological relevance. To predict the functions of the identified lncRNAs, we extracted mRNAs that were nearby loci and highly correlated with the lncRNAs. RESULTS: In total of 5,946 lncRNA and 12,354 mRNA transcripts were identified among the samples. STEM showed that most lncRNAs and mRNAs had similar temporal expression patterns during development, indicating the expressional correlation and functional relatedness between them. The five stages were divided into two classes: the suckling period and the late developmental stage. Most genes were expressed at low level during the suckling period, but at higher level during the late stages. Expression of several T-cell-related genes increased continuously during the suckling period, indicating that these genes are crucial for establishing the adaptive immune system in piglets at this stage. Notably, lncRNA TCONS-00086451may promote blood-based immune system development by upregulating nuclear factor of activated T-cells cytoplasmic 2 expression. CONCLUSION: This study provides a catalog of porcine peripheral blood-related lncRNAs and mRNAs and reveals the characteristics and temporal expression profiles of these lncRNAs and mRNAs during peripheral blood development from the newborn to adult stages in pigs.

Optical design and evaluation of airborne prism-grating imaging spectrometer.

We have focused on the optical form that is low cost while maintaining high performance for airborne application. We report the optical design as well as the alignment and test results for a push-broom imaging spectrometer. The smart architecture of the prism-grating based spectrometer ensures high uniformity and image quality. Moreover, an effective method for aligning the spectrometer is also proposed. The results of laboratory-based optical tests and a flight test confirm the easy manufacture and excellent performance. Thus, the proposed system should be suitable for use as a hyperspectral instrument that can be loaded onto airborne and unmanned aerial vehicles.

Terahertz dispersion using multi-depth phase modulation grating.

We present a multi-depth phase modulation grating (MPMG) in the terahertz range making real-time multichannel Fourier-transform spectroscopy available in a stationary manner. The calculation of the Fraunhofer diffraction field distribution and diffraction efficiency of an MPMG indicates that the zeroth-order diffraction light of an MPMG carries phase information and its diffraction intensity is modulated by the groove depth. A good agreement is found between the measurements of the 0th- and ±1st-order diffraction efficiency at 0.5 and 0.34 THz and the simulation. The frequencies of the terahertz source retrieved from the zeroth-order diffraction intensity at 0.5, 0.4, and 0.34 THz are identical to the actual frequencies.

The Scientific Information Model of Chang'e-4 Visible and Near-IR Imaging Spectrometer (VNIS) and In-Flight Verification.

The Chang'e-4 (CE-4) lunar rover, equipped with a visible and near-IR imaging spectrometer (VNIS) based on acousto-optic tunable filter spectroscopy, was launched to the far side of the moon on December 8, 2018. The detection band of the VNIS ranges from 0.45 to 2.4 µm. Because of the weak reflection of infrared radiation from the lunar surface, a static electronic phase-locked acquisition method is adopted in the infrared channel for signal amplification. In this paper, full-link simulations and modeling are conducted on the infrared channel information flow of the instrument. The signal characteristics of the VNIS are analyzed in depth, and the signal to noise ratio (SNR) prediction and laboratory verification are presented. On 4 January 2019, the VNIS started working successfully and acquired high-resolution spectrum data of the far side of the moon for the first time. Through analysis we have found that the SNR ratio is in line with our predictions, and the data obtained by VNIS in orbit are consistent with the information model proposed in this paper.

Terahertz communication windows and their point-to-point transmission verification: publisher's note.

This publisher's note amends the author affiliations in Appl. Opt.57, 7673 (2018)APOPAI0003-693510.1364/AO.57.007673.

Terahertz communication windows and their point-to-point transmission verification.

Terahertz communication is recognized as a transformational technology that can meet the future demands of point-to-point communication. The study of terahertz atmospheric transmission characteristics is important for guiding the terahertz communication window selection process. In this report, based on the modified ITU-R P.676-10 model, we determined that the terahertz communication windows above 100 GHz were located at the bands at approximately 140, 220, 340, 410, and 460 GHz, which is verified by recent experiments. We also verified the feasibility of indoor point-to-point communication by the 110 m transmission experiment through the communication window around 460 GHz.