Composition Modulation Research Articles

Effects of xylo-oligosaccharide supplementation on the production performance, intestinal morphology, cecal short-chain fatty acid levels, and gut microbiota of laying hens

This study investigated the effects of xylo-oligosaccharide supplementation on the production performance, intestinal morphology, cecal short-chain fatty acid levels, and gut microbiota of laying hens. A total of 800 Lohmann pink layers, each 48 wk old, were randomly divided into 5 dietary treatment groups, namely XOS at 0 (CON), 100 (XOS1), 200 (XOS2), 300 (XOS3) and 400 (X0S4) mg/kg. The experimental period was 24 wk. The results revealed that the egg production rate and the number of eggs laid by each layer between 1 to 12 wk increased as the XOS concentration increased (Plinear < 0.05). The sand-shell egg percentage decreased significantly from 1 to 12 wk in the XOS1, XOS2, and XOS3 groups (PANOVA < 0.05). Compared with the CON group, the 4 XOS dosage groups presented significant increases in the villus height and the ratio of villus height to crypt depth in the jejunum (PANOVA < 0.05), whereas a linear decrease in jejunal crypt depth (Plinear < 0.05) was noted. In addition, XOS supplementation significantly increased the concentrations of butyric acid and isovaleric acid in the caeca (PANOVA < 0.05). High-throughput sequencing analysis of bacterial 16S rRNA revealed that dietary XOS supplementation influenced the cecal microbiota. The alpha diversity analysis indicated that the richness of cecal bacteria was greater in the laying hens fed XOS. The modulation of the cecal microbiota composition upon the addition of XOS was characterized by an increased abundance of Firmicutes and Bifidobacteriaceae, and decreased abundance of Bacteroidetes. At the genus level, dietary XOS supplementation resulted in decreases in the abundances of Bacteroides and Rikenellaceae_RC9_gut_group and an increase in the abundance of Lactobacillus. In conclusion, dietary XOS supplementation improved the production performance of laying hens by increasing the production of short-chain fatty acids and improving their intestinal morphology, which was achieved mainly through changes in the composition of the intestinal microbiota. The recommended level of XOS in the diet of laying hens is 200 mg/kg.

An investigation of Ti addition to optimize the tribological properties of TiCrNbTaW refractory high-entropy alloy

Many refractory high-entropy alloys (RHEAs) with high melting points suffer from severe wear-fracture failures due to compositional segregation, which is a key factor limiting their widespread application as structural parts. In this work, two novel TixCrNbTaW (x = 1 and 1.5) RHEAs were prepared using composition modulation and liquid phase assisted sintering strategies. The results showed that the further addition of Ti enhanced the strength, toughness and microstructural homogeneity of the RHEAs, which effectively suppressed the wear-fracture behavior. In addition, the dense oxidized amorphous layer formed in-situ has higher hardness than the matrix, which can provide additional load-bearing capacity. The synergistic effect of the above factors promotes the wear rate of Ti1.5 alloy to be as low as 2.9 × 10−5 mm3/(N·m). The present work provides some insights into the design of high anti-wear RHEAs.

Optimized bimodal silver particle sintering for high thermal conductivity die-attach layers

A bimodal silver system can achieve higher effective thermal conductivity (ETC) than a mono-system for electronic packaging. However, the effect of micron- and submicron-particle compositions on the microstructure and ETC of sintered Ag is unclear. In this study, Ag films with varying particle compositions were fabricated by pulsed laser deposition. The results indicate that the sintered bimodal Ag film with 76 vol% submicron-particles possesses the highest ETC (260 W m−1 K−1). This enhancement is attributed to the decreased porosity, increased pore circularity and pore distribution uniformity. This particle composition modulation strategy can provide a guideline for developing high-performance die-attach materials for electronic packaging.

Modulation of p-Block Electron Orbits in Metal-Organic Frameworks for CO2 Capture and Electrochemical Reduction.

Developing catalysts with excellent CO2 capture capability and electrochemical CO2 reduction reaction (CO2RR) at a wide potential range simultaneously is significant but remains a formidable challenge. Here, two novel InMg defective trinuclear cluster-based MOFs (SNNU-41 and SNNU-42) with abundant p-block unsaturated coordinated sites were reported and exhibited good CO2 capture and CO2RR performance simultaneously. Due to the suitable micropores, SNNU-41 showed higher CO2 capture ability at different adsorption pressure conditions. On account of the rigid framework and the closer p band center to Fermi level, SNNU-42 accelerated the conversion of CO2 molecule to C1 efficiency. Notably, via adjusting the ratio of p-block metal (In) in the SNNU-42 framework, the performance of the CO2RR was promoted drastically. SNNU-42 with the InMg (1:1.8) mixed cluster delivered an excellent Faradaic efficiency of 91.3% for C1 products and high selectivity of 72.0% for HCOOH at -2.5 V (vs Ag/Ag+) with a total current density of 77.2 mA cm-2. This work provides a possibility for efficient CO2 capture and CO2RR electrocatalysts through the modulation of electronic structures and composition in MOFs.

Optimised phase compositions and achieved ultra-high Q×f values in Ca(2+y)Sn2Al(2+x)O(9+1.5x+y) ceramics by composition modulation

The optimization of phase compositions and microwave dielectric properties in Ca(2+y)Sn2Al(2+x)O(9+1.5x + y) (−0.2 ≤ x ≤ 0.2, −0.2 ≤ y ≤ 0.2) ceramics were investigated. The change in Al content could inhibit the SnO2 second phase of Ca2Sn2Al2O9 ceramic, and the Al deficiency in Ca2Sn2Al(2+x)O(9+1.5x) (−0.2 ≤ x < 0) ceramics contributed to the increase in the content of the CaSnO3 second phase. The enrichment of the Al content could not inhibit the CaSnO3 second phase, and the low content of the CaSnO3 second phase was obtained in Ca2Sn2Al(2+x)O(9+1.5x) (0 < x ≤ 0.2) ceramics. The high content of CaSnO3 second phase was also observed in Ca(2+y)Sn2Al2O(9+y) (0 < y ≤ 0.2) ceramics, and the enrichment of Ca induced the CaSnO3 second phase. Moreover, the slight Ca deficiency inhibited the SnO2 and CaSnO3 second phases, and the Ca2Sn2Al2O9 single-phase ceramic was obtained in Ca(2+y)Sn2Al2O(9+y) (y = −0.1). The Ca(2+y)Sn2Al(2+x)O(9+1.5x + y) (−0.2 ≤ x ≤ 0.2, −0.2 ≤ y ≤ 0.2) ceramics with a high content of CaSnO3 second phases exhibited high εr and moderate Q × f values, which were controlled by the ρrel and the content of the CaSnO3 second phase, respectively. The Q × f value was sensitive to the second phases, and Ca-deficient Ca(2+y)Sn2Al2O(9+y) (y = −0.1) ceramic with Ca2Sn2Al2O9 single-phase composition exhibited the ultra-high Q × f value (Q × f = 121818 GHz at 11.86 GHz).

Based on improved joint detection and tracking of UAV for multi-target detection of livestock

In agriculture, specifically livestock monitoring, drones' ability to track multiple targets is essential for advancing the field. However, limited computing resources and unpredictable drone movements often cause issues like ambiguous video frames, object obstructions, and size deviations. These inconsistencies reduce tracking accuracy, making traditional algorithms inadequate for handling drone footage. This study introduces an enhanced deep learning-based multi-target drone tracker framework that enables real-time processing. The proposed method combines object detection and tracking by leveraging consecutive frame pairs to extract and share features, enhancing computational efficiency. It employs diverse loss functions to address class and sample distribution imbalances and includes a composite deblurring module to enhance detection accuracy. Object association utilizes a dual regress bounding box technique, aiding in object identification verification and predictive motion. Live tracking is achieved by predicting object locations in subsequent frames, enabling real-time tracking. Evaluation against leading benchmarks shows that the system improves precision and speed, achieving a 4.3 % increase in Multi-Object Tracking Accuracy (MOTA) and a 7.7 % boost in F1 score.

Ganoderma lucidum polysaccharide promotes broiler health by regulating lipid metabolism, antioxidants, and intestinal microflora

Ganoderma lucidum polysaccharides (GLP) are the primary bioactive macromolecular compounds of Ganoderma lucidum, possessing antioxidant and immunomodulatory effects. Hot water extract of Juncao-substrate Ganoderma Lucidum residue (HWE-JGLR) is abundant in GLP. There are few research reports on the application of HWE-JGLR in animal husbandry. Therefore, this study aims to investigate the effects of HWE-JGLR supplementation on growth performance, serum biochemistry, the antioxidant function of serum and liver, and the intestinal microbiota of yellow-feathered broilers. The control group was fed a corn-soybean meal basal diet, while the HJ I, II, and III groups received diets supplemented with 0.25 %, 0.5 %, and 1 % of HWE-JGLR, respectively. Results showed that HWE-JGLR increased the serum HDL-C content and decreased the TG content in broilers. Moreover, HWE-JGLR enhanced the antioxidant function by the Keap1-Nrf2/ARE signaling pathway and the antioxidative enzyme in broilers. In addition, the cecum of the metagenomic analysis of 16S rRNA showed that the relative abundance of no-rank Ruminococcacea was increased in the HJ I group. Our findings indicate that HWE-JGLR has strong potential for development as a green feed additive based on its functions of lipid-lowering, antioxidation, and the modulation of gut microbiota composition.

Efficient structural and compositional modulation of vanadium oxides for high-areal-capacity zinc-ion batteries

Although rechargeable aqueous zinc-ion batteries (RAZIBs) have been revitalized as competitive candidates for large-scale energy storage, the development of this technology is stalled by the underutilization of cathode materials due to sluggish reaction kinetics, resulting in low areal capacities that cannot meet the practical requirements. Herein, this study reveals a simple, efficient, and low-energy synthetic route to effectively convert relatively inactive α-V2O5 (131 mAh g−1 at 0.1 A g−1) into highly active MxV8O20·nH2O (MVO, M = Li, Na, and K) by liquid-phase dissolution-recrystallization reaction and chemical preintercalation under low-temperature conditions. Particularly, NaVO presents the most expansive diffusion channel, the highest specific surface area, and the smallest band gap, allowing faster electron/ion transport kinetics and better material utilization. With these features, NaVO accommodates electrolyte Zn2+ and H+ with good reversibility, showing high capacity (383 mAh g−1 at 0.1 A g−1) and rate-performance (207 mAh g−1 at 8 A g−1). More importantly, high-areal-capacity of 3.2 mAh cm−2 and remarkable cycle stability over 1500 cycles can be achieved from free-standing high-mass-loading electrode (∼14 mg cm−2) made of NaVO and multi-walled carbon nanotubes (MWCNTs). This work enriches the synthetic methods for obtaining high-performance vanadium-based host materials with practical areal capacity and cycle stability.

Dissolved organic matter (DOM) rather than warming and eutrophication directly affects partial pressure of CO2 (pCO2) in mesocosm systems

Environmental warming and eutrophication pose significant challenges to shallow lake systems, where dissolved organic matter (DOM) serves as a diverse and intricate mixture of organic macromolecules, playing a pivotal role in aquatic ecosystems. Despite its complexity, comprehending the interplay between environmental changes and DOM composition alterations and their subsequent impacts on aqueous CO2 partial pressure (pCO2) is essential for a better understanding of carbon cycling. Yet, our current understanding in this realm remains limited. To address this gap, mesocosm systems were established to investigate how elevated water temperature and eutrophication, alongside changes in DOM composition, influence pCO2 dynamics. Results indicate that while temperature and nutrient levels do not directly influence pCO2 fluctuations, they indirectly affect aqueous pCO2 through their modulation of DOM composition. Elevated temperature and nutrient concentrations notably enhance both the production and degradation of indigenous protein-like organic matter and increase the accumulation of humic-like organic compounds, with phosphorus released from sediment playing a particularly significant role. Furthermore, the degradation rate of protein-like organic matter significantly exceeds its accumulation rate. On the other hand, the impact of water eutrophication on DOM composition surpasses that of temporal temperature variations, with a 2∼4 °C temperature rise showing minimal effects on DOM composition. Notably, the degradation of protein-like organic matter markedly increases aqueous pCO2, while the rise in humic-like organic matter in water exerts minimal influence on pCO2 concentrations. A comprehensive understanding of carbon cycling processes under environmental changes will facilitate effective management of lake ecosystems and the advancement of carbon mitigation technologies.

Baseline immune state and T-cell clonal kinetics are associated with durable response to CAR-T therapy in large B-cell lymphoma

AbstractEngineered cellular therapy with CD19-targeting chimeric antigen receptor T cells (CAR-Ts) has revolutionized outcomes for patients with relapsed/refractory large B-cell lymphoma (LBCL), but the cellular and molecular features associated with response remain largely unresolved. We analyzed serial peripheral blood samples ranging from the day of apheresis (day –28/baseline) to 28 days after CAR-T infusion from 50 patients with LBCL treated with axicabtagene ciloleucel by integrating single-cell RNA and T-cell receptor sequencing, flow cytometry, and mass cytometry to characterize features associated with response to CAR-T. Pretreatment patient characteristics associated with response included the presence of B cells and increased absolute lymphocyte count to absolute monocyte count ratio (ALC/AMC). Infusion products from responders were enriched for clonally expanded, highly activated CD8+ T cells. We expanded these observations to 99 patients from the ZUMA-1 cohort and identified a subset of patients with elevated baseline B cells, 80% of whom were complete responders. We integrated B-cell proportion ≥0.5% and ALC/AMC ≥1.2 into a 2-factor predictive model and applied this model to the ZUMA-1 cohort. Estimated progression-free survival at 1 year in patients meeting 1 or both criteria was 65% vs 31% for patients meeting neither criterion. Our results suggest that patients’ immunologic state at baseline affects the likelihood of response to CAR-T through both modulation of the T-cell apheresis product composition and promoting a more favorable circulating immune compartment before therapy. These baseline immunologic features, measured readily in the clinical setting before CAR-T, can be applied to predict response to therapy.

Analysis of the nutritional composition, biological activities, and phenolic metabolic bioactive module of cherry tomatoes

This study analyzed the overall nutritional composition of 87 cherry tomato varieties and evaluated the antioxidant, hypoglycemic, and hypolipidemic activities of the top 30 varieties with excellent overall quality. In addition, the phenolic metabolic characteristics of cherry tomatoes were determined via phenolic metabolomics, and the bioactive module “phenolic-DPPH” was identified. There was extensive interspecies variation in total soluble solids, titratable acid, lycopene, chlorophyll, γ-aminobutyric acid, total phenolics, total flavonoids and multivitamins, and different color groups presented unique nutritional compositions. The comprehensive nutritional value of the 56 varieties is greater than that of the Millennium variety. Phenolic substances are closely related to DPPH free radical scavenging activity. A total of 484 phenolic substances were identified, among which 5′-methoxymatairesinoside and 6-hydroxykaempferol-7,6-O-diglucoside are key antioxidant components. Our research provides valuable resources and insights for the selection of functional cherry tomato varieties and the identification of phenolics with important biological activities.

Widely Untargeted Metabolomics Profiling Combined with Transcriptome Analysis Provides New Insight into Amino Acid Biosynthesis at Different Developmental Stages of Rubus Chingii Hu (Chinese Raspberry).

The composition and profile of amino acids in Rubus chingii (R. chingii) Hu serve as critical indicators of its nutritional quality. A comprehensive understanding of the amino acid metabolism within R. chingii is instrumental in the formulation and innovation of functional foods derived from this species. Utilizing advanced techniques such as wide-ranging untargeted metabolomics, transcriptome analysis, interaction network mapping, heat map analysis, and quantitative real-time PCR, we conducted a comprehensive assessment of the quality attributes across four distinct developmental stages of R. chingii. Our meticulous analysis uncovered a rich tapestry of 76 distinct amino acids and their derivatives within the developmental stages of R. chingii. The spectrum of essential amino acids was not only broad but also displayed a high degree of variety. Notably, leucine, lysine, and phenylalanine stood out as the most abundant amino acids, underscoring their significant presence throughout the growth cycle of R. chingii. The proportion of essential amino acids relative to the total amino acid content in R. chingii exhibited a notable trajectory of change throughout its developmental stages. It began with 30.92% in the immature green phase, advanced to 31.04% during the transition from green to yellow, peaked at 33.62% in the yellow to red stage, and then moderated to 30.43% in the full red phase. This pattern suggests a strategic modulation of amino acid composition, aligning with the evolving nutritional requirements and metabolic shifts as the fruit matures. Concurrent analysis of interaction networks and heat maps, alongside comprehensive profiling of amino acid metabolism and transcriptomic examination, was conducted to elucidate the intricate dynamics of cellular processes. The results showed that seven differentially expressed genes (DEGs) played important roles in amino acid metabolism, including PFK, BCAT1, TSB, ASA, ACO, TOM2AH3, and BCAT2. The expression patterns of seven DEGs conformed closely to the findings revealed by the preceding RNA-seq analysis. In this investigation, we elucidated the regulatory mechanisms underlying amino acid metabolism across the four distinct developmental stages of R. chingii through comprehensive amino acid profiling and transcriptomic analysis. These insights lay the groundwork for the development of novel functional food applications utilizing R. chingii.

Growth promotion and modulation of the soybean microbiome INTACTA RR PRO with the application of the fungi Trichoderma harzianum and Purpureocillum lilacinum

Soybean is an economically important crop for animal and human nutrition. Currently, there is a lack of information on the effects of Trichoderma harzianum and Purpureocillum lilacinum on INTACTA RR PRO transgenic soybean plants. The present study evaluated the application of T. harzianum and P. lilacinum under field conditions. The results revealed a significant increase in soybean yield at 423 kg ha−1 in response to the application of P. lilacinum compared with the control treatment. In addition, the application of P. lilacinum promoted a significant increase in phosphorus levels in the plant leaves, and there were significant correlations between the increase in taxon abundance for the genus Erwinia and productivity and the average phosphorus and nitrogen content for the plant leaves, for the taxon Bacillus and nitrogen content and productivity, and for the taxon Sphingomonas and nitrogen content. The Bradyrhizobium taxon was identified in the P. lilacinum treatment as a taxon linking two different networks of taxa and is an important taxon in the microbiota. The results show that the application of the fungus P. lilacinum can increase the productivity of soybean INTACTA RR PRO and that this increase in productivity may be a function of the modulation of the microbiota composition of the plant leaves by the P. lilacinum effect.

Reduction in Olfactory Discomfort in Inhabited Premises from Areas with Mofettas through Cellulosic Derivative-Polypropylene Hollow Fiber Composite Membranes.

Hydrogen sulfide is present in active or extinct volcanic areas (mofettas). The habitable premises in these areas are affected by the presence of hydrogen sulfide, which, even in low concentrations, gives off a bad to unbearable smell. If the living spaces considered are closed enclosures, then a system can be designed to reduce the concentration of hydrogen sulfide. This paper presents a membrane-based way to reduce the hydrogen sulfide concentration to acceptable limits using a cellulosic derivative-propylene hollow fiber-based composite membrane module. The cellulosic derivatives considered were: carboxymethyl-cellulose (NaCMC), P1; cellulose acetate (CA), P2; methyl 2-hydroxyethyl-cellulose (MHEC), P3; and hydroxyethyl-cellulose (HEC), P4. In the permeation module, hydrogen sulfide is captured with a solution of cadmium that forms cadmium sulfide, usable as a luminescent substance. The composite membranes were characterized by SEM, EDAX, FTIR, FTIR 2D maps, thermal analysis (TG and DSC), and from the perspective of hydrogen sulfide air removal performance. To determine the process performances, the variables were as follows: the nature of the cellulosic derivative-polypropylene hollow fiber composite membrane, the concentration of hydrogen sulfide in the polluted air, the flow rate of polluted air, and the pH of the cadmium nitrate solution. The pertraction efficiency was highest for the sodium carboxymethyl-cellulose (NaCMC)-polypropylene hollow fiber membrane, with a hydrogen sulfide concentration in the polluted air of 20 ppm, a polluted air flow rate (QH2S) of 50 L/min, and a pH of 2 and 4. The hydrogen sulfide flux rates, for membrane P1, fall between 0.25 × 10-7 mol·m2·s-1 for the values of QH2S = 150 L/min, CH2S = 20 ppm, and pH = 2 and 0.67 × 10-7 mol·m-2·s-1 for the values of QH2S = 50 L/min, CH2S = 60 ppm, and pH = 2. The paper proposes a simple air purification system containing hydrogen sulfide, using a module with composite cellulosic derivative-polypropylene hollow fiber membranes.

EFFECTS OF PREBIOTICS ON METABOLIC ACTIVITY IN BROILERS

The present study will aim to assess the effects of prebiotic supplementation on growth performance, protein metabolism, and gut health in broiler chickens using mannan-oligosaccharides (MOS) as a model prebiotic. The purpose is to determine if prebiotics will be beneficial alternatives for antibiotic growth promoters in improving the flock performance and meeting quality-related parameters in broilers. A 42-day randomized controlled trial on one-day-old Ross 308 broiler chicks will be divided into four groups: Control, Inulin (IN), MOS, and FOS. The study shall determine Body Weight Gain (BWG), Feed Intake (FI), Feed Conversion Ratio (FCR), Protein Digestibility, Lipid content, &amp; Gut Microbiota composition using 16S rRNA sequencing. Anticipated criteria include improvement in body weight gain (BWG), feed conversion ratio (FCR), protein digestibility, and beneficial modulation of gut microbiota composition at successively higher pricing than the control group, which are shown as MOS. The study will also record a decrease in saturated fatty acids and an increase in polyunsaturated fatty acids in the breast muscle, which indicates improved meat quality. These results will add to the literature that provides evidence for using prebiotics as a natural substitution in poultry nutrition due to its benefits. The research results will highlight the possibility of using MOS as an alternative to antibiotics in broiler diets and their effect on growth performance (with meat quality) and gut health. Nonetheless, the limitations of the short study duration and only using one broiler strain will be noted, with suggestions to replicate these findings over extended periods in more strains to validate prebiotics in poultry nutrition.

MFAD-RTDETR: A Multi-Frequency Aggregate Diffusion Feature Flow Composite Model for Printed Circuit Board Defect Detection

To address the challenges of excessive model parameters and low detection accuracy in printed circuit board (PCB) defect detection, this paper proposes a novel PCB defect detection model based on the improved RTDETR (Real-Time Detection, Embedding and Tracking) method, named MFAD-RTDETR. Specifically, the proposed model introduces the designed Detail Feature Retainer (DFR) into the original RTDETR backbone to capture and retain local details. Subsequently, based on the Mamba architecture, the Visual State Space (VSS) module is integrated to enhance global attention while reducing the original quadratic complexity to a linear level. Furthermore, by exploiting the deformable attention mechanism, which dynamically adjusts reference points, the model achieves precise localization of target defects and improves the accuracy of the transformer in complex visual tasks. Meanwhile, a receptive field synthesis mechanism is incorporated to enrich multi-scale semantic information and reduce parameter complexity. In addition, the scheme proposes a novel Multi-frequency Aggregation and Diffusion feature composite paradigm (MFAD-feature composite paradigm), which consists of the Aggregation Diffusion Fusion (ADF) module and the Refiner Feature Composition (RFC) module. It aims to strengthen features with fine-grained awareness while preserving a certain level of global attention. Finally, the Wise IoU (WIoU) dynamic nonmonotonic focusing mechanism is used to reduce competition among high-quality anchor boxes and mitigate the effects of the harmful gradients from low-quality examples, thereby concentrating on anchor boxes of average quality to promote the overall performance of the detector. Extensive experiments are conducted on the PCB defect dataset released by Peking University to validate the effectiveness of the proposed model. The experimental results show that our approach achieves the 97.0% and 51.0% performance in mean Average Precision (mAP)@0.5 and mAP@0.5:0.95, respectively, which significantly outperforms the original RTDETR. Moreover, the model reduces the number of parameters by approximately 18.2% compared to the original RTDETR.

A systematic study on wear behavior of TiCrNbTaWx refractory high-entropy alloy: Inducing amorphization to achieve anti-wear

Refractory high-entropy alloys (RHEAs) possess exceptional properties at elevated temperatures. However, their limited wear resistance at room temperature (RT) hinders their widespread application. In this work, based on compositional modulation and surface engineering strategies, two TiCrNbTaWx (x = 0, 0.5) RHEAs were prepared using spark plasma sintering. The results show that the addition of W can effectively improve the hardness (10.3 GPa) and deformation resistance of the BCC matrix, alleviating the severe adhesion and the fracture behavior. In addition, the friction-induced oxidized amorphous layer with high hardness (12.3 GPa) can further improve the anti-wear properties. Because of these, the TiCrNbTaW0.5 alloy has a low wear rate of 9 × 10−5 mm−3·N−1·m−1, which is 67 % lower than the pristine TiCrNbTa alloy. In conclusion, our design strategy provides a new idea for designing RT wear-resistant RHEAs.

Enhanced ABLO-OFDM performance by using composite multi-mode index modulation in IM/DD systems

In intensity modulation direct detection (IM/DD) systems, an adaptively biased layered optical orthogonal frequency division multiplexing (ABLO-OFDM) scheme is proposed based on composite multi-mode index modulation (CMM-IM). The ABLO-OFDM has a simple structure, easy demodulation, low complexity, and effectively reduces the peak-to-average power ratio (PAPR). Since CMM-IM extends the index to the constellation domain, it increases the number of index bits to further improve the spectral efficiency (SE). By dynamically adjusting the number of activated subcarriers and the number of layers, various signal power can be achieved to enhance system flexibility and reliability. The system performance of four schemes is compared and analyzed in IM/DD systems. The result shows that, for the same SE, CMM-ABLO (4,3) achieves a 3 dB receiver sensitivity gain compared with CMM-ABLO (8,2). When L is 3, four schemes can transmit over about 50 km single-mode fiber under the soft decision forward error correction (SD-FEC) threshold. When L is 1 and the sample rate is less than 20 GSa/s, both CMM-ABLO (4,2) and CMM-ABLO (4,3) can achieve error-free transmission. Moreover, as the number of layers increases, PAPR decreases and it reaches a maximum reduction of 9.6 dB.

Towards the scalable synthesis of two-dimensional heterostructures and superlattices beyond exfoliation and restacking.

Two-dimensional transition metal dichalcogenides, which feature atomically thin geometry and dangling-bond-free surfaces, have attracted intense interest for diverse technology applications, including ultra-miniaturized transistors towards the subnanometre scale. A straightforward exfoliation-and-restacking approach has been widely used for nearly arbitrary assembly of diverse two-dimensional (2D) heterostructures, superlattices and moiré superlattices, providing a versatile materials platform for fundamental investigations of exotic physical phenomena and proof-of-concept device demonstrations. While this approach has contributed importantly to the recent flourishing of 2D materials research, it is clearly unsuitable for practical technologies. Capturing the full potential of 2D transition metal dichalcogenides requires robust and scalable synthesis of these atomically thin materials and their heterostructures with designable spatial modulation of chemical compositions and electronic structures. The extreme aspect ratio, lack of intrinsic substrate and highly delicate nature of the atomically thin crystals present fundamental difficulties in material synthesis. Here we summarize the key challenges, highlight current advances and outline opportunities in the scalable synthesis of transition metal dichalcogenide-based heterostructures, superlattices and moiré superlattices.

Single-Shot Multispectral Encoding: Advancing Optical Lithography for Encryption and Spectroscopy.

Most modern optical display and sensing devices utilize a limited number of spectral units within the visible range, based on human color perception. In contrast, the rapid advancement of machine-based pattern recognition and spectral analysis could facilitate the use of multispectral functional units, yet the challenge of creating complex, high-definition, and reproducible patterns with an increasing number of spectral units limits their widespread application. Here, we report a technique for optical lithography that employs a single-shot exposure to reproduce perovskite films with spatially controlled optical band gaps through light-induced compositional modulations. Luminescent patterns are designed to program correlations between spatial and spectral information, covering the entire visible spectral range. Using this platform, we demonstrate multispectral encoding patterns for encryption and multivariate optical converters for dispersive optics-free spectroscopy with high spectral resolution. The fabrication process is conducted at room temperature and can be extended to other material and device platforms.