Realizing transmissive and reflective focusing with an on-chip metalens.

A metalens made of compact planar metastructure exhibits an excellent capability of focusing. The high-quality transmissive and reflective focusing simultaneously provides Fourier transform (FT) operation for optical information processing. Here we show a transflective on-chip metalens (TOM) made of orthogonal nano-grooves (ONGs). The TOM simultaneously converges transmitted and reflected (T&R) waves to the designed focal points. By adjusting the phase gradient profiles provided by the ONGs, the focal lengths of the T&R in-plane waves can be independently tuned. Our simulations show that the TOM possesses the advantages of broadband (>400 nm bandwidth) and high-focusing-efficiency (∼60%) dual-focusing capability. Further, we utilize the TOM to build a one-to-two 4-f optical system. Two different spatial filtering operations based on FT can be simultaneously implemented in axial transmission and off-axis reflection channels for one input signal. We expect that the dual-focusing metalens approach can realize parallel optical processing in on-chip optical computing, spatial filtering, and beyond.

MRI Findings of Pituitary Gland in Growth Hormone-Deficient Children and Their Correlation with Growth Hormone Peak during Growth Hormone Stimulation Tests.

This study aims to explore the magnetic resonance imaging (MRI) findings of the pituitary gland (PG) in children with growth hormone deficiency (GHD) and their correlation with the growth hormone (GH) peak during clinical GH stimulation tests. Sixty-one children with GHD diagnosed and treated between December 2018 and December 2021 were retrospectively analyzed in terms of clinical and pituitary morphological MRI data. MRI measurements of various diameters of the adenohypophysis (AH) were obtained to analyze the differences of the measured values in different genders and age groups, as well as their relationship with the GH peak in GH stimulation tests. Among the 61 children with GHD, the superior PG margin was protuberant in 2 cases, flat in 13 cases, and concave in 46 cases. The three age groups showed similar pituitary morphology and stalk (P > 0.05). On T1-weighted images, the proportion of isointensity was lower while the proportion of slightly-low signal intensity was higher in the anterior pituitary gland (APG) of children aged >10 compared with those aged 7-10. The comparison of AH linear parameters and GH peak values of male patients among different age groups showed that the anteroposterior (sagittal) diameter of AH and GH peak were the highest in the >10-year-old group and the lowest in the ≤6-year-old group, with those of the 7-10-year-old group in between (P < 0.05). In females, the anteroposterior (sagittal) diameter and GH peak were higher in the 7-10-year-old group and >10-year-old group compared with the ≤6-year-old group (P < 0.05). The MRI coronal and sagittal heights of PG in children with GHD were positively correlated with the GH peak value. In conclusion, in GHD patients, the coronal and sagittal heights as well as the coronal width of AH do not change with sex or age, but the coronal and sagittal heights of PG are positively correlated with the GH peak of GH stimulation tests, which has high application value in the diagnosis of children with GHD.

An oligotrophic deep-subsurface community dependent on syntrophy is dominated by sulfur-driven autotrophic denitrifiers.

Subsurface lithoautotrophic microbial ecosystems (SLiMEs) under oligotrophic conditions are typically supported by H2 Methanogens and sulfate reducers, and the respective energy processes, are thought to be the dominant players and have been the research foci. Recent investigations showed that, in some deep, fluid-filled fractures in the Witwatersrand Basin, South Africa, methanogens contribute <5% of the total DNA and appear to produce sufficient CH4 to support the rest of the diverse community. This paradoxical situation reflects our lack of knowledge about the in situ metabolic diversity and the overall ecological trophic structure of SLiMEs. Here, we show the active metabolic processes and interactions in one of these communities by combining metatranscriptomic assemblies, metaproteomic and stable isotopic data, and thermodynamic modeling. Dominating the active community are four autotrophic ß-proteobacterial genera that are capable of oxidizing sulfur by denitrification, a process that was previously unnoticed in the deep subsurface. They co-occur with sulfate reducers, anaerobic methane oxidizers, and methanogens, which each comprise <5% of the total community. Syntrophic interactions between these microbial groups remove thermodynamic bottlenecks and enable diverse metabolic reactions to occur under the oligotrophic conditions that dominate in the subsurface. The dominance of sulfur oxidizers is explained by the availability of electron donors and acceptors to these microorganisms and the ability of sulfur-oxidizing denitrifiers to gain energy through concomitant S and H2 oxidation. We demonstrate that SLiMEs support taxonomically and metabolically diverse microorganisms, which, through developing syntrophic partnerships, overcome thermodynamic barriers imposed by the environmental conditions in the deep subsurface.

Structure and mechanical properties of new biomass-based nanocomposite: castor oil-based polyurethane reinforced with acetylated cellulose nanocrystal.

New nanocomposites consisting of a castor oil-based polyurethane matrix filled with acetylated cellulose nanocrystals (ACNs) were developed. The ACN exhibited improved dispersion in tetrahydrofuran as a blending medium, and reduced polarity as compared with unmodified cellulose nanocrystals, resulting in a high loading level of 25 wt% in the nanocomposite. As the ACN loading-level increased from 0% to 25%, the tensile strength and Young's modulus of the nanocomposites increased from 2.79 MPa to 10.41 MPa and from 0.98 MPa to 42.61 MPa, respectively. When the ACN loading-level was 10 wt%, the breaking elongation of the nanocomposites reached the maximum value of more than twice that of the polyurethane. The enhanced mechanical performance was primarily attributed to the formation of a three-dimensional ACN network and strong interfacial interactions between filler and matrix. This work produced new polyurethane-based nanocomposites containing modified cellulose nanocrystal with a high biomass content. Its high performance could contribute to potential applications.