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Thin films based on two-dimensional metal halide perovskites have achieved exceptional performance and stability in numerous optoelectronic device applications. Simple solution processing of the 2D perovskite provides opportunities for manufacturing devices at drastically lower cost compared to current commercial technologies. A key to high device performance is to align the 2D perovskite layers, during the solution processing, vertical to the electrodes to achieve efficient charge transport. However, it is yet to be understood how the counter-intuitive vertical orientations of 2D perovskite layers on substrates can be obtained. Here we report a formation mechanism of such vertically orientated 2D perovskite in which the nucleation and growth arise from the liquid–air interface. As a consequence, choice of substrates can be liberal from polymers to metal oxides depending on targeted application. We also demonstrate control over the degree of preferential orientation of the 2D perovskite layers and its drastic impact on device performance. It is desirable to align the two-dimensional perovskite layers vertical to the electrodes to maximize device performance but the formation mechanism is unclear. Here Chen et al. reveal that the film formation starts at the liquid-air interface and is thus independent of the choice of substrates.

Thin films grown via atomic layer deposition (ALD) suffer from insufficient growth rate and unreliability for temperature-sensitive electronic substrates. This study aimed to examine the growth characteristics and dielectric strength of ALD Al 2 O 3 films grown at low temperatures (≤ 150 °C) for potential application in flexible electronic devices. The growth rate of the Al 2 O 3 films increased from 0.9 to 1.1 Å/cycle with increasing temperature and saturated at growth temperatures ≥ 150 °C, which is the critical temperature at which a complete oxidation reaction occurred. The dielectric strength was also improved with increasing growth temperature, and the films grown at 150 °C showed a high breakdown field strength (~ 8.3 MV/cm), attributable to the decrease in the carbon impurities and oxygen defects, as confirmed by X-ray photoelectron spectroscopy. Even at low growth temperatures (≤ 150 °C), ALD Al 2 O 3 films showed an overall amorphous structure and extremely smooth surfaces regardless of the growth temperature.

The transmission of loads across the soil-structure mobilizes direction-dependent shear resistance, which can be selectively used to design geo-structures. A previous study confirmed the frictional anisotropy induced by the interface between the soil and snakeskin-inspired surfaces. However, it is necessary to estimate the interface friction angle quantitatively. In this study, a conventional direct shear apparatus is modified, and 45 cases are performed in two-way shearing directions between bio-inspired surfaces and Jumunjin standard sand under three vertical stresses (50, 100, and 200 kPa). The results show that: (1) shearing against the scales (cranial shearing) mobilizes larger shear resistance and produces a dilative response than shearing along the scales (caudal shearing) and (2) higher scale height or shorter scale length exhibits dilative tendency and produces higher interface friction angle. Further analysis is conducted to capture the frictional anisotropy as a function of the scale geometry ratio, which reveals that the interface anisotropy response is more pronounced during cranial shearing in all the cases, and the difference in the interface friction angle for the caudal → cranial test is higher than that for the cranial → caudal test at the given scale ratio.

Long carrier lifetime is what makes hybrid organic–inorganic perovskites high-performance photovoltaic materials. Several microscopic mechanisms behind the unusually long carrier lifetime have been proposed, such as formation of large polarons, Rashba effect, ferroelectric domains, and photon recycling. Here, we show that the screening of band-edge charge carriers by rotation of organic cation molecules can be a major contribution to the prolonged carrier lifetime. Our results reveal that the band-edge carrier lifetime increases when the system enters from a phase with lower rotational entropy to another phase with higher entropy. These results imply that the recombination of the photoexcited electrons and holes is suppressed by the screening, leading to the formation of polarons and thereby extending the lifetime. Thus, searching for organic–inorganic perovskites with high rotational entropy over a wide range of temperature may be a key to achieve superior solar cell performance.

Understanding direction-dependent friction anisotropy is necessary to optimize interface shear resistance across soil-structure. Previous studies estimated interface frictional anisotropy quantitatively using contractive sands. However, no studies have explored how sand with a high dilative tendency around the structural surface affects the interface shear response. In this study, a series of interface direct shear tests are conducted with selected French standard sand and snakeskin-inspired surfaces under three vertical stresses (50, 100, and 200 kPa) and two shearing directions (cranial → caudal or caudal → cranial). First, the sand-sand test observes a higher dilative response, and a significant difference between the peak and residual friction angles (ϕ peak − ϕ res  = 8°) is obtained at even a lower initial relative density D r  = 40%. In addition, the interface test results show that (1) shearing against the scales (cranial shearing) mobilizes a larger shear resistance and produces a dilative response than shearing along the scales (caudal shearing), (2) a higher scale height or shorter scale length exhibits a higher dilative tendency and produces a higher interface friction angle, and (3) the interface anisotropy response is more pronounced during cranial shearing in all cases. Further analysis reveals that the interface friction angle and dilation angle are decreased with the scale geometry ratio (L/H). For L/H values between 16.67 and 60, the interface dilation angle varies between 9° and 4° for cranial first shearing and 3.9°–2.6° for caudal first shearing. However, the difference in dilation angle within the same shearing direction is less than 1°.

Femoral neck fracture is a common osteoporotic fracture in elderly patients and is effectively managed with arthroplasty. However, the benefits and risks of a surgical drain after arthroplasty in these patients are still debatable. Hence, we conducted this study to investigate the necessity of a surgical drain after hemiarthroplasty in elderly patients with femoral neck fracture. This study enrolled elderly patients (aged ≥ 70 years) who underwent cementless bipolar hemiarthroplasty for femoral neck fracture between April 2016 and December 2021. The patients were divided into two groups; the control group (199 patients) with a surgical drain after surgery performed between April 2016 and June 2020 and the study group (134 patients) with no surgical drain between July 2020 and December 2021. The demographics, perioperative data, and postoperative complications were compared between the two groups. Estimated blood loss, perioperative transfusion volume and rate, and length of hospital stay were significantly lower in the study group than in the control group (p < 0.001, p < 0.001, p = 0.008, and p < 0.001, respectively). Although there were no significant intergroup differences in the length of intensive care unit stay and in-hospital, 1-month, and 1-year mortalities, the incidence of postoperative medical complications was significantly lower in the study group than the control group (p = 0.001). A surgical drain may be unnecessary after hemiarthroplasty in elderly patients with femoral neck fracture considering less blood loss and transfusion, lower incidence of postoperative medical complications, and shorter hospital stay in the study group with no surgical drain.

The pursuit of quantum spin liquid (QSL) states in condensed matter physics has drawn attention to kagome antiferromagnets (AFM) where a two-dimensional corner-sharing network of triangles frustrates conventional magnetic orders. While quantum kagome AFMs based on Cu 2+ (3d 9 , s = ½) ions have been extensively studied, there is so far little work beyond copper-based systems. Here we present our bulk magnetization, specific heat and neutron scattering studies on single crystals of a new titanium fluorides Cs 8 RbK 3 Ti 12 F 48 where Ti 3+ (3d 1 , s = ½) ions form a modulated quantum kagome antiferromagnet that does not order magnetically down to 1.5 K. Our comprehensive map of the dynamic response function S ( Q , ℏ ω ) acquired at 1.5 K where the heat capacity is T -linear reveals a dispersive continuum emanating from soft lines that extend along (100). The data indicate fractionalized spinon-like excitations with quasi-one-dimensional dispersion within a quasi-two-dimensional spin system. Kagome antiferromagnets have been extensively studied as potential hosts of quantum spin liquids. However, example materials have been largely limited to Cu-based systems. Here, Thennakoon et al. establish, via a combination of specific heat, magnetization and neutron scattering measurements, a Ti-based quantum Kagome antiferromagnet, Cs 8 RbK 3 Ti 12 F 48 , as a strong candidate for hosting quantum spin liquid.

The great cormorant ( Phalacrocorax carbo ) is a migratory, fish-eating bird that may act as a carrier for various pathogens, raising potential ecological and public health concerns. This study investigated the diversity of gastrointestinal parasites in great cormorants from the Republic of Korea using 18S rRNA gene metabarcoding and conventional diagnostic methods. Fecal samples were collected from 10 great cormorants in Korea, and DNA was extracted for metabarcoding targeting the V4 and V9 regions of the 18S rRNA gene using the MiSeq platform. Conventional PCR and microscopic examination were used for validation. The V4 region of the 18S rRNA gene revealed the presence of Baruscapillaria spiculata , Contracaecum sp., and Isospora lugensae . The V9 region analysis identified the following parasites: Tetratrichomonas sp., Histomonas meleagridis, Trichomitus sp., Tetratrichomonas prowazekii , B. obsignata, Monosiga ovata , and Fasciola gigantica . Furthermore, conventional PCR confirmed the presence of Contracaecum sp., Isospora sp., and unspecified trichomonads, and microscopic examination identified eggs of capillarid, Contracaecum , and Eustrongylides and trophozoites of flagellated protozoa in the collected cormorant fecal samples. The findings underscored the potential ecological role of great cormorants as hosts for diverse gastrointestinal parasites and the utility of 18S rRNA gene metabarcoding for screening the diversity of gastrointestinal parasites in great cormorants.

Ticks are blood-sucking ectoparasites that act as vectors for transmission of various pathogens. The purpose of this study was to assess tick-borne bacteria, whether pathogenic or not, in ticks distributed in Korea using 16S rRNA metabarcoding and to confirm the results by PCR. Questing ticks were collected from four provinces in Korea in 2021 using the flagging method. After pooling the DNAs from the 61 tick pools (including 372 ticks), the bacterial 16S rRNA V3–V4 hypervariable region was amplified and sequenced using the MiSeq platform. Rickettsia , Ehrlichia , and the endosymbiont Wolbachia were confirmed by conventional PCR and molecular analysis. In total, 6907 ticks (534 pools) were collected and identified as belonging to five species ( Haemaphysalis spp., H. longicornis , H. flava , I. nipponensis , and A. testudinarium ). Through 16S rRNA metabarcoding, 240 amplicon sequence variants were identified. The dominant taxa were Rickettsiella and Coxiella. Additionally, pathogenic bacteria such as Rickettsia and Ehrlichia, endosymbiotic bacteria such as Wolbachia and Spiroplasma were identified . Polymerase chain reaction (PCR) was performed to confirm the presence of Rickettsia, Ehrlichia , Bartonella , and Wolbachia in individual ticks. Overall, 352 (65.92%) of 534 pools tested positive for at least one of the screened tick-borne bacteria. Rickettsia was the most prevalent (61.42%), followed by Wolbachia (5.05%). Ehrlichia was detected in 4.86% of tested samples, whereas Bartonella was not detected. In this study, 16S rRNA metabarcoding revealed the presence of Rickettsia, Wolbachia , and Ehrlichia , in that order of abundance, while showing absence of Bartonella . These results were confirmed to exhibit the same trend as that of the conventional PCR. Therefore, large-scale screening studies based on pooling, as applied in this study, will be useful for examining novel or rare pathogens present in various hosts and vectors.

Coffee roasting is the process of applying heat to green coffee beans to bring out flavors through chemical changes. This study aimed to investigate the effect of roasting degree on the antioxidant capacities of espresso and drip coffee extracted from Coffea arabica cv. Java in Laos. Green coffee beans were roasted under four conditions (Light-medium, Medium, Moderately dark, and Very dark), and espresso and drip coffee were extracted. The contents of total phenolics (TP), total flavonoids (TF), and chlorogenic acids (CGA) decreased as the roasting degree increased, whereas the caffeine content increased. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity was lower in the Medium, Moderately dark, and Very dark compared to the Light-medium. The ferric reducing antioxidant power (FRAP) was lower in the Very dark than the Light-medium, Medium, and Moderately dark. Principal component analysis showed that TP, TF, CGA, caffeine, DPPH radical scavenging activity, and FRAP distinguish coffee extracts with various roasting degrees. Therefore, it is concluded that roasting degree is a modifiable factor for the use of coffee as an antioxidant material in the food industry, and TF, TP, CGA, and caffeine contents, DPPH radical scavenging activity and FRAP are good indicators for determining the antioxidant capacity of coffee.