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1.
Nature ; 610(7933): 674-679, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-36253468

RESUMEN

Reconfigurable, mechanically responsive crystalline materials are central components in many sensing, soft robotic, and energy conversion and storage devices1-4. Crystalline materials can readily deform under various stimuli and the extent of recoverable deformation is highly dependent upon bond type1,2,5-10. Indeed, for structures held together via simple electrostatic interactions, minimal deformations are tolerated. By contrast, structures held together by molecular bonds can, in principle, sustain much larger deformations and more easily recover their original configurations. Here we study the deformation properties of well-faceted colloidal crystals engineered with DNA. These crystals are large in size (greater than 100 µm) and have a body-centred cubic (bcc) structure with a high viscoelastic volume fraction (of more than 97%). Therefore, they can be compressed into irregular shapes with wrinkles and creases, and, notably, these deformed crystals, upon rehydration, assume their initial well-formed crystalline morphology and internal nanoscale order within seconds. For most crystals, such compression and deformation would lead to permanent, irreversible damage. The substantial structural changes to the colloidal crystals are accompanied by notable and reversible optical property changes. For example, whereas the original and structurally recovered crystals exhibit near-perfect (over 98%) broadband absorption in the ultraviolet-visible region, the deformed crystals exhibit significantly increased reflection (up to 50% of incident light at certain wavelengths), mainly because of increases in their refractive index and inhomogeneity.


Asunto(s)
Coloides , ADN , Coloides/química , ADN/química , Tamaño de la Partícula , Electricidad Estática , Cristalización
2.
Proc Natl Acad Sci U S A ; 121(6): e2309457121, 2024 Feb 06.
Artículo en Inglés | MEDLINE | ID: mdl-38289949

RESUMEN

Relating the macroscopic properties of protein-based materials to their underlying component microstructure is an outstanding challenge. Here, we exploit computational design to specify the size, flexibility, and valency of de novo protein building blocks, as well as the interaction dynamics between them, to investigate how molecular parameters govern the macroscopic viscoelasticity of the resultant protein hydrogels. We construct gel systems from pairs of symmetric protein homo-oligomers, each comprising 2, 5, 24, or 120 individual protein components, that are crosslinked either physically or covalently into idealized step-growth biopolymer networks. Through rheological assessment, we find that the covalent linkage of multifunctional precursors yields hydrogels whose viscoelasticity depends on the crosslink length between the constituent building blocks. In contrast, reversibly crosslinking the homo-oligomeric components with a computationally designed heterodimer results in viscoelastic biomaterials exhibiting fluid-like properties under rest and low shear, but solid-like behavior at higher frequencies. Exploiting the unique genetic encodability of these materials, we demonstrate the assembly of protein networks within living mammalian cells and show via fluorescence recovery after photobleaching (FRAP) that mechanical properties can be tuned intracellularly in a manner similar to formulations formed extracellularly. We anticipate that the ability to modularly construct and systematically program the viscoelastic properties of designer protein-based materials could have broad utility in biomedicine, with applications in tissue engineering, therapeutic delivery, and synthetic biology.


Asunto(s)
Materiales Biocompatibles , Hidrogeles , Animales , Hidrogeles/química , Biopolímeros , Mamíferos
3.
Nat Mater ; 23(3): 424-428, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-37919350

RESUMEN

In principle, designing and synthesizing almost any class of colloidal crystal is possible. Nonetheless, the deliberate and rational formation of colloidal quasicrystals has been difficult to achieve. Here we describe the assembly of colloidal quasicrystals by exploiting the geometry of nanoscale decahedra and the programmable bonding characteristics of DNA immobilized on their facets. This process is enthalpy-driven, works over a range of particle sizes and DNA lengths, and is made possible by the energetic preference of the system to maximize DNA duplex formation and favour facet alignment, generating local five- and six-coordinated motifs. This class of axial structures is defined by a square-triangle tiling with rhombus defects and successive on-average quasiperiodic layers exhibiting stacking disorder which provides the entropy necessary for thermodynamic stability. Taken together, these results establish an engineering milestone in the deliberate design of programmable matter.


Asunto(s)
ADN , ADN/genética , ADN/química , Termodinámica
4.
Blood ; 141(6): 567-578, 2023 02 09.
Artículo en Inglés | MEDLINE | ID: mdl-36399715

RESUMEN

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic malignancy with historically poor outcomes and no worldwide consensus treatment approach. Unique among most hematologic malignancies for its frequent cutaneous involvement, BPDCN can also invade other extramedullary compartments, including the central nervous system. Generally affecting older adults, many patients are unfit to receive intensive chemotherapy, and although hematopoietic stem cell transplantation is preferred for younger, fit individuals, not all are eligible. One recent therapeutic breakthrough is that all BPDCNs express CD123 (IL3Rα) and that this accessible surface marker can be pharmacologically targeted. The first-in-class agent for BPDCN, tagraxofusp, which targets CD123, was approved in December 2018 in the United States for patients with BPDCN aged ≥2 years. Despite favorable response rates in the frontline setting, many patients still relapse in the setting of monotherapy, and outcomes in patients with relapsed/refractory BPDCN remain dismal. Therefore, novel approaches targeting both CD123 and other targets are actively being investigated. To begin to formally address the state of the field, we formed a new collaborative initiative, the North American BPDCN Consortium (NABC). This group of experts, which includes a multidisciplinary panel of hematologists/oncologists, hematopoietic stem cell transplant physicians, pathologists, dermatologists, and pediatric oncologists, was tasked with defining the current standard of care in the field and identifying the most important research questions and future directions in BPDCN. The position findings of the NABC's inaugural meetings are presented herein.


Asunto(s)
Neoplasias Hematológicas , Trastornos Mieloproliferativos , Neoplasias Cutáneas , Niño , Humanos , Anciano , Nivel de Atención , Subunidad alfa del Receptor de Interleucina-3 , Células Dendríticas/patología , Recurrencia Local de Neoplasia/patología , Trastornos Mieloproliferativos/patología , Neoplasias Hematológicas/patología , Neoplasias Cutáneas/patología , Enfermedad Aguda , América del Norte
5.
Biochem Biophys Res Commun ; 702: 149618, 2024 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-38340658

RESUMEN

Patatin-like phospholipase domain-containing 1 (PNPLA1) is crucial in the esterification of linoleic acid (LA; 18:2n-6) to ω-hydroxy fatty acids (FA) of ceramide 1 (Cer1), the major barrier lipid of the differentiated epidermis. We previously reported that γ-linolenic acid (GLA; 18:3n-6) as well as LA is esterified to Cer1 subspecies with sphingosine (d18:1) or eicosasphingosine (d20:1) amide-linked to two different ω-hydroxy FA (30wh:0; 32wh:1). Here, we further investigated whether PNPLA1 is also responsible for esterification of GLA to these Cer1 subspecies in normal human keratinocytes (NHK). As late/terminal differentiation was induced in NHK, PNPLA1 and differentiation markers were expressed, and LA-esterified Cer1 subspecies (18:2n-6/C30wh:0 or C32wh:0/d18:1; 18:2n-6/C32wh:0/d20:1) were detected, which were further increased with LA treatment. GLA-esterified Cer1 subspecies (18:3n-6/C30wh:0 or C32wh:0/d18:1; 18:3n-6/C32wh:0/d20:1) were detected only with GLA treatment. Specific small interfering RNA-mediated knockdown of PNPLA1 (KDP) in differentiated NHK decreased levels of these LA-esterified Cer1 subspecies overall and of involucrin (IVL), a terminal differentiation marker. Moreover, KDP resulted in lesser LA/GLA responses as characterized by more significant decreases in IVL and LA/GLA-esterified Cer1 subspecies overall and an accumulation of non-esterified ω-hydroxy ceramides, their putative precursors; the decrease of 18:3n-6/C32wh:0/d18:1, the predominant GLA-esterified Cer1 subspecies, specifically paralleled the increase of C32wh:0/d18:1, its corresponding precursor. PNPLA1 is responsible for NHK terminal differentiation and also for esterification of GLA to the ω-hydroxy FA of Cer1.


Asunto(s)
Queratinocitos , Ácido gammalinolénico , Humanos , Ácido gammalinolénico/metabolismo , Esterificación , Epidermis/metabolismo , Ceramidas/metabolismo , Ácidos Grasos/metabolismo , Ácido Linoleico/metabolismo , Aciltransferasas/metabolismo , Fosfolipasas/metabolismo
6.
Small ; 20(25): e2308925, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38268229

RESUMEN

III-VI metal chalcogenides have garnered considerable research attention as a novel group of layered van der Waals materials because of their exceptional physical properties and potential technological applications. Here, the epitaxial growth and stacking sequences of InTe is reported, an essential and intriguing material from III-VI metal chalcogenides. Aberration-corrected scanning transmission electron microscopy (STEM) is utilized to directly reveal the interlayer stacking modes and atomic structure, leading to a discussion of a new polytype. Furthermore, correlations between the stacking sequences and interlayer distances are substantiated by atomic-resolution STEM analysis, which offers evidence for strong interlayer coupling of the new polytype. It is proposed that layer-by-layer deposition is responsible for the formation of the unconventional stacking order, which is supported by ab initio density functional theory calculations. The results thus establish molecular beam epitaxy as a viable approach for synthesizing novel polytypes. The experimental validation of the InTe polytype here expands the family of materials in the III-VI metal chalcogenides while suggesting the possibility of new stacking sequences for known materials in this system.

7.
Small ; : e2403147, 2024 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-38989706

RESUMEN

All-solid-state batteries (ASSBs) possess the advantage of ensuring safety while simultaneously maximizing energy density, making them suitable for next-generation battery models. In particular, sulfide solid electrolytes (SSEs) are viewed as promising candidates for ASSB electrolytes due to their excellent ionic conductivity. However, a limitation exists in the form of interfacial side reactions occurring between the SSEs and cathode active materials (CAMs), as well as the generation of sulfide-based gases within the SSE. These issues lead to a reduction in the capacity of CAMs and an increase in internal resistance within the cell. To address these challenges, cathode composite materials incorporating zinc oxide (ZnO) are fabricated, effectively reducing various side reactions occurring in CAMs. Acting as a semiconductor, ZnO helps mitigate the rapid oxidation of the solid electrolyte facilitated by an electronic pathway, thereby minimizing side reactions, while maintaining electron pathways to the active material. Additionally, it absorbs sulfide-based gases, thus protecting the lithium ions within CAMs. In this study, the mass spectrometer is employed to observe gas generation phenomena within the ASSB cell. Furthermore, a clear elucidation of the side reactions occurring at the cathode and the causes of capacity reduction in ASSB are provided through density functional theory calculations.

8.
Small ; : e2401989, 2024 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-38855993

RESUMEN

The minimally invasive deployment of scaffolds is a key safety factor for the regeneration of cartilage and bone defects. Osteogenesis relies primarily on cell-matrix interactions, whereas chondrogenesis relies on cell-cell aggregation. Bone matrix expansion requires osteoconductive scaffold degradation. However, chondrogenic cell aggregation is promoted on the repellent scaffold surface, and minimal scaffold degradation supports the avascular nature of cartilage regeneration. Here, a material satisfying these requirements for osteochondral regeneration is developed by integrating osteoconductive hydroxyapatite (HAp) with a chondroconductive shape memory polymer (SMP). The shape memory function-derived fixity and recovery of the scaffold enabled minimally invasive deployment and expansion to fill irregular defects. The crystalline phases on the SMP surface inhibited cell aggregation by suppressing water penetration and subsequent protein adsorption. However, HAp conjugation SMP (H-SMP) enhanced surface roughness and consequent cell-matrix interactions by limiting cell aggregation using crystal peaks. After mouse subcutaneous implantation, hydrolytic H-SMP accelerated scaffold degradation compared to that by the minimal degradation observed for SMP alone for two months. H-SMP and SMP are found to promote osteogenesis and chondrogenesis, respectively, in vitro and in vivo, including the regeneration of rat osteochondral defects using the binary scaffold form, suggesting that this material is promising for osteochondral regeneration.

9.
Gastrointest Endosc ; 99(4): 633-640, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38092126

RESUMEN

BACKGROUND AND AIMS: The incidence, risk factors, and outcomes of post-ERCP cholecystitis are poorly described. We aimed to describe cases of post-ERCP cholecystitis from a prospective multicenter registry with protocolized 30-day follow-up. METHODS: Patient- and procedure-related data from 7 centers were obtained. The primary outcome was post-ERCP cholecystitis, defined according to a Delphi-based criteria and causal attribution system. Risk factors and outcomes were described for all cases. RESULTS: Seventeen cases of post-ERCP cholecystitis were identified among 4428 patients with gallbladders undergoing ERCP between 2018 and 2023 (incidence, 0.38%; 95% confidence interval, 0.20-0.57). In ERCPs with covered metal stenting, 7 of 467 resulted in cholecystitis (incidence, 1.50%; 95% confidence interval, 0.40-2.60). Patients had symptoms at a median of 5 days (interquartile range, 5) after ERCP. Management strategies included cholecystectomy, percutaneous cholecystostomy, and endoscopic stent removal/exchange. CONCLUSIONS: Estimates of post-ERCP cholecystitis incidence can inform discussions around procedural risk.


Asunto(s)
Sistema Biliar , Colecistitis , Humanos , Colangiopancreatografia Retrógrada Endoscópica/efectos adversos , Colecistitis/epidemiología , Colecistitis/etiología , Incidencia , Estudios Prospectivos , Estudios Retrospectivos , Estudios Multicéntricos como Asunto
10.
Langmuir ; 40(16): 8630-8635, 2024 Apr 23.
Artículo en Inglés | MEDLINE | ID: mdl-38587497

RESUMEN

Microfluidic platforms have been widely used in a variety of fields owing to their numerous advantages. The prevention and prompt removal of air bubbles from microchannels are important to ensuring the optimal functioning of microfluidic devices. The entrapment of bubbles in the microchannels can result in flow instability and device performance disruption. Active and passive methods are the primary categories of degassing technologies. Active methods rely on external equipment, and passive methods operate autonomously without any external sources. This study proposed a passive degassing method that employs a nanoscale surface morphology integrated into the substrate of a microfluidic device. Nanostructures exhibit a microchannel geometry and are fabricated based on surface micromachining technology using silver ink and chemical etching. Consequently, the gas permeability is enhanced, resulting in effective degassing through the nanostructure. The performance of this degassing method was characterized under varying substrate permeabilities and input pressure conditions, and it was found that increased permeability facilitates the degassing performance. Furthermore, the applicability of our method was demonstrated by using a serpentine channel design prone to gas entrapment, particularly in the corner regions. The nanostructured substrate exhibited significantly improved degassing performance under the given pressure conditions in comparison to the glass substrate.

11.
Fish Shellfish Immunol ; 144: 109266, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38043872

RESUMEN

Oncorhynchus mykiss, a significant aquaculture species, possesses compounds with numerous biological and pharmacological functions, including antioxidant, anticancer, anti-microbial, and anti-obesity effects. However, possible anti-inflammatory effects of lipids extracted from O. mykiss eggs on RAW264.7 cells induced by LPS have not been elucidated yet. The current study identified 13 fatty acids in lipids extracted from O. mykiss eggs that contained high amounts (51.92% of total fatty acids) of polyunsaturated fatty acids (PUFAs), especially DHA (33.66%) and EPA (7.77%). These O. mykiss lipids (100-400 µg/mL) showed significant anti-inflammatory effects by inhibiting NO and iNOS expression in LPS-stimulated RAW264.7 cells. They also inhibited expression of pro-inflammatory cytokines IL-1ß, IL-6, and TNF-α, while upregulating anti-inflammatory cytokines IL-10, IL-11, and TGF-ß. These lipids from O. mykiss effectively inhibited LPS-induced expression CD86 as a surface biomarker on RAW264.7 cells. Additionally, O. mykiss lipids suppressed phosphorylation of p38, JNK, and ERK1/2 and the expression of phosphorylated NF-κB subunit p65. These findings indicate that O. mykiss lipids possess anti-inflammatory properties by inhibiting NF-κB and MAPK signaling pathways.


Asunto(s)
Ácidos Grasos , Oncorhynchus mykiss , Animales , Ratones , Antiinflamatorios/farmacología , Citocinas/genética , Citocinas/metabolismo , Ácidos Grasos/farmacología , Inflamación/tratamiento farmacológico , Lipopolisacáridos , FN-kappa B/genética , FN-kappa B/metabolismo , Oncorhynchus mykiss/metabolismo , Células RAW 264.7
12.
Anesth Analg ; 139(3): 562-570, 2024 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-38412113

RESUMEN

BACKGROUND: The effect of sevoflurane on left ventricular diastolic function is not well understood. We hypothesized that parameters of diastolic function may improve under sevoflurane anesthesia in patients with preexisting diastolic dysfunction compared to patients with normal diastolic function. METHODS: This observational study included 60 patients undergoing breast surgery or laparoscopic cholecystectomy. Patients were assigned to diastolic dysfunction (n = 34) or normal (n = 26) groups of septal e' < 8 or ≥ 8.0 cm/s on the first thoracic echocardiography (TTE) performed before anesthesia. During anesthesia, sevoflurane was maintained at 1 to 2 minimum alveolar concentration (MAC) to maintain the bispectral index at 40 to 50. At the end of surgery, the second TTE was performed under 0.8 to 1 MAC of sevoflurane with the patient breathing spontaneously without ventilator support. Primary end point was the percentage change (Δ) of e' on 2 TTEs (Δe'). Secondary end points were ΔE/e', Δleft atrial volume index (ΔLAVI), and Δtricuspid regurgitation maximum velocity (ΔTR Vmax). These percentage changes (Δ) were compared between diastolic dysfunction and normal groups. RESULTS: e' (Δe': 30 [6, 64] vs 0 [-18, 11]%; P < .001), mitral inflow E wave velocity (E), mitral inflow E/A ratio (E/A), and mitral E velocity deceleration time (DT) improved significantly in diastolic dysfunction group compared to normal group. LAVI decreased in diastolic dysfunction group but did not reach statistical significance between the 2 groups (ΔLAVI:-15 [-31, -3] vs -4 [-20, 10]%, P = .091). ΔE/e' was not different between the 2 groups (11 [-16, 26] vs 12 [-9, 22]%, P = .853) (all: median [interquartile range, IQR]). TR was minimal in both groups. CONCLUSIONS: In this study, echocardiographic parameters of diastolic function, including septal e', E, E/A, and DT, improved with sevoflurane anesthesia in patients with preexisting diastolic dysfunction, but remained unchanged in patients with normal diastolic function.


Asunto(s)
Anestésicos por Inhalación , Diástole , Sevoflurano , Función Ventricular Izquierda , Humanos , Sevoflurano/administración & dosificación , Femenino , Estudios Prospectivos , Persona de Mediana Edad , Anestésicos por Inhalación/administración & dosificación , Diástole/efectos de los fármacos , Masculino , Anciano , Función Ventricular Izquierda/efectos de los fármacos , Disfunción Ventricular Izquierda/fisiopatología , Disfunción Ventricular Izquierda/diagnóstico por imagen , Éteres Metílicos/administración & dosificación , Colecistectomía Laparoscópica , Adulto
13.
Mar Drugs ; 22(8)2024 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-39195484

RESUMEN

This study was conducted to evaluate the potential anti-inflammatory and immune-enhancement properties of lipids derived from Aptocyclus ventricosus eggs on RAW264.7 cells. Firstly, we determined the fatty acid compositions of A. ventricosus lipids by performing gas chromatography analysis. The results showed that A. ventricosus lipids contained saturated fatty acids (24.37%), monounsaturated fatty acids (20.90%), and polyunsaturated fatty acids (54.73%). They also contained notably high levels of DHA (25.91%) and EPA (22.05%) among the total fatty acids. Our results for the immune-associated biomarkers showed that A. ventricosus lipids had immune-enhancing effects on RAW264.7 cells. At the maximum dose of 300 µg/mL, A. ventricosus lipids generated NO (119.53%) and showed greater phagocytosis (63.69%) ability as compared with untreated cells. A. ventricosus lipids also upregulated the expression of iNOS, IL-1ß, IL-6, and TNF-α genes and effectively upregulated the phosphorylation of MAPK (JNK, p38, and ERK) and NF-κB p65, indicating that these lipids could activate the MAPK and NF-κB pathways to stimulate macrophages in the immune system. Besides their immune-enhancing abilities, A. ventricosus lipids significantly inhibited LPS-induced RAW264.7 inflammatory responses via the NF-κB and MAPK pathways. The results indicated that these lipids significantly reduced LPS-induced NO production, showing a decrease from 86.95% to 38.89%. Additionally, these lipids downregulated the expression of genes associated with the immune response and strongly suppressed the CD86 molecule on the cell surface, which reduced from 39.25% to 33.80%. Collectively, these findings imply that lipids extracted from A. ventricosus eggs might have biological immunoregulatory effects. Thus, they might be considered promising immunomodulatory drugs and functional foods.


Asunto(s)
FN-kappa B , Transducción de Señal , Animales , Ratones , Células RAW 264.7 , FN-kappa B/metabolismo , Transducción de Señal/efectos de los fármacos , Lípidos , Macrófagos/efectos de los fármacos , Antiinflamatorios/farmacología , Antiinflamatorios/química , Antiinflamatorios/aislamiento & purificación , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Huevos , Fagocitosis/efectos de los fármacos , Ácidos Grasos/farmacología , Óxido Nítrico/metabolismo , Citocinas/metabolismo
14.
Mar Drugs ; 22(8)2024 Jul 27.
Artículo en Inglés | MEDLINE | ID: mdl-39195460

RESUMEN

The subcritical water extraction of Undaria pinnatifida (blade, sporophyll, and root) was evaluated to determine its chemical properties and biological activities. The extraction was conducted at 180 °C and 3 MPa. Root extracts exhibited the highest phenolic content (43.32 ± 0.19 mg phloroglucinol/g) and flavonoid content (31.54 ± 1.63 mg quercetin/g). Sporophyll extracts had the highest total sugar, reducing sugar, and protein content, with 97.35 ± 4.23 mg glucose/g, 56.44 ± 3.10 mg glucose/g, and 84.93 ± 2.82 mg bovine serum albumin (BSA)/g, respectively. The sporophyll contained the highest fucose (41.99%) and mannose (10.37%), whereas the blade had the highest galactose (48.57%) and glucose (17.27%) content. Sporophyll had the highest sulfate content (7.76%). Key compounds included sorbitol, glycerol, L-fucose, and palmitic acid. Root extracts contained the highest antioxidant activity, with IC50 values of 1.51 mg/mL (DPPH), 3.31 mg/mL (ABTS+), and 2.23 mg/mL (FRAP). The root extract exhibited significant α-glucosidase inhibitory activity with an IC50 of 5.07 mg/mL, indicating strong antidiabetic potential. The blade extract showed notable antihypertensive activity with an IC50 of 0.62 mg/mL. Hence, subcritical water extraction to obtain bioactive compounds from U. pinnatifida, supporting their use in functional foods, cosmetics, and pharmaceuticals is highlighted. This study uniquely demonstrates the variation in bioactive compound composition and bioactivities across different parts of U. pinnatifida, providing deeper insights. Significant correlations between chemical properties and biological activities emphasize the use of U. pinnatifida extracts for chronic conditions.


Asunto(s)
Antioxidantes , Extractos Vegetales , Undaria , Antioxidantes/farmacología , Antioxidantes/aislamiento & purificación , Antioxidantes/química , Undaria/química , Extractos Vegetales/farmacología , Extractos Vegetales/química , Extractos Vegetales/aislamiento & purificación , Agua/química , Raíces de Plantas/química , Flavonoides/aislamiento & purificación , Flavonoides/farmacología , Flavonoides/química , Antihipertensivos/farmacología , Antihipertensivos/aislamiento & purificación , Antihipertensivos/química , Fenoles/aislamiento & purificación , Fenoles/farmacología , Fenoles/química , Inhibidores de Glicósido Hidrolasas/farmacología , Inhibidores de Glicósido Hidrolasas/aislamiento & purificación , Inhibidores de Glicósido Hidrolasas/química , Hipoglucemiantes/farmacología , Hipoglucemiantes/química , Hipoglucemiantes/aislamiento & purificación , Algas Comestibles
15.
Proc Natl Acad Sci U S A ; 118(7)2021 02 16.
Artículo en Inglés | MEDLINE | ID: mdl-33563761

RESUMEN

Quasicrystals have been discovered in a variety of materials ranging from metals to polymers. Yet, why and how they form is incompletely understood. In situ transmission electron microscopy of alloy quasicrystal formation in metals suggests an error-and-repair mechanism, whereby quasiperiodic crystals grow imperfectly with phason strain present, and only perfect themselves later into a high-quality quasicrystal with negligible phason strain. The growth mechanism has not been investigated for other types of quasicrystals, such as dendrimeric, polymeric, or colloidal quasicrystals. Soft-matter quasicrystals typically result from entropic, rather than energetic, interactions, and are not usually grown (either in laboratories or in silico) into large-volume quasicrystals. Consequently, it is unknown whether soft-matter quasicrystals form with the high degree of structural quality found in metal alloy quasicrystals. Here, we investigate the entropically driven growth of colloidal dodecagonal quasicrystals (DQCs) via computer simulation of systems of hard tetrahedra, which are simple models for anisotropic colloidal particles that form a quasicrystal. Using a pattern recognition algorithm applied to particle trajectories during DQC growth, we analyze phason strain to follow the evolution of quasiperiodic order. As in alloys, we observe high structural quality; DQCs with low phason strain crystallize directly from the melt and only require minimal further reduction of phason strain. We also observe transformation from a denser approximant to the DQC via continuous phason strain relaxation. Our results demonstrate that soft-matter quasicrystals dominated by entropy can be thermodynamically stable and grown with high structural quality--just like their alloy quasicrystal counterparts.

16.
J Korean Med Sci ; 39(9): e87, 2024 Mar 11.
Artículo en Inglés | MEDLINE | ID: mdl-38469963

RESUMEN

BACKGROUND: Prolonged length of hospital stay (LOS) is associated with an increased risk of hospital-acquired conditions and worse outcomes. We conducted a nationwide, multicenter, retrospective cohort study to determine whether prolonged hospitalization before developing sepsis has a negative impact on its prognosis. METHODS: We analyzed data from 19 tertiary referral or university-affiliated hospitals between September 2019 and December 2020. Adult patients with confirmed sepsis during hospitalization were included. In-hospital mortality was the primary outcome. The patients were divided into two groups according to their LOS before the diagnosis of sepsis: early- (< 5 days) and late-onset groups (≥ 5 days). Conditional multivariable logistic regression for propensity score matched-pair analysis was employed to assess the association between late-onset sepsis and the primary outcome. RESULTS: A total of 1,395 patients were included (median age, 68.0 years; women, 36.3%). The early- and late-onset sepsis groups comprised 668 (47.9%) and 727 (52.1%) patients. Propensity score-matched analysis showed an increased risk of in-hospital mortality in the late-onset group (adjusted odds ratio [aOR], 3.00; 95% confidence interval [CI], 1.69-5.34). The same trend was observed in the entire study population (aOR, 1.85; 95% CI, 1.37-2.50). When patients were divided into LOS quartile groups, an increasing trend of mortality risk was observed in the higher quartiles (P for trend < 0.001). CONCLUSION: Extended LOS before developing sepsis is associated with higher in-hospital mortality. More careful management is required when sepsis occurs in patients hospitalized for ≥ 5 days.


Asunto(s)
Hospitalización , Sepsis , Adulto , Anciano , Femenino , Humanos , Mortalidad Hospitalaria , Tiempo de Internación , Pronóstico , Estudios Retrospectivos , Masculino
17.
J Korean Med Sci ; 39(8): e75, 2024 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-38442718

RESUMEN

BACKGROUND: Limited data are available on the mortality rates of patients receiving extracorporeal membrane oxygenation (ECMO) support for coronavirus disease 2019 (COVID-19). We aimed to analyze the relationship between COVID-19 and clinical outcomes for patients receiving ECMO. METHODS: We retrospectively investigated patients with COVID-19 pneumonia requiring ECMO in 19 hospitals across Korea from January 1, 2020 to August 31, 2021. The primary outcome was the 90-day mortality after ECMO initiation. We performed multivariate analysis using a logistic regression model to estimate the odds ratio (OR) of 90-day mortality. Survival differences were analyzed using the Kaplan-Meier (KM) method. RESULTS: Of 127 patients with COVID-19 pneumonia who received ECMO, 70 patients (55.1%) died within 90 days of ECMO initiation. The median age was 64 years, and 63% of patients were male. The incidence of ECMO was increased with age but was decreased after 70 years of age. However, the survival rate was decreased linearly with age. In multivariate analysis, age (OR, 1.048; 95% confidence interval [CI], 1.010-1.089; P = 0.014) and receipt of continuous renal replacement therapy (CRRT) (OR, 3.069; 95% CI, 1.312-7.180; P = 0.010) were significantly associated with an increased risk of 90-day mortality. KM curves showed significant differences in survival between groups according to age (65 years) (log-rank P = 0.021) and receipt of CRRT (log-rank P = 0.004). CONCLUSION: Older age and receipt of CRRT were associated with higher mortality rates among patients with COVID-19 who received ECMO.


Asunto(s)
COVID-19 , Oxigenación por Membrana Extracorpórea , Humanos , Masculino , Persona de Mediana Edad , Anciano , Femenino , COVID-19/terapia , Estudios Retrospectivos , Muerte , Factores de Riesgo
18.
Sensors (Basel) ; 24(3)2024 Jan 29.
Artículo en Inglés | MEDLINE | ID: mdl-38339578

RESUMEN

Silicon nanowires (SiNWs) are emerging as versatile components in the fabrication of sensors for implantable medical devices because of their exceptional electrical, optical, and mechanical properties. This paper presents a novel top-down fabrication method for vertically stacked SiNWs, eliminating the need for wet oxidation, wet etching, and nanolithography. The integration of these SiNWs into body channel communication (BCC) circuits was also explored. The fabricated SiNWs were confirmed to be capable of forming arrays with multiple layers and rows. The SiNW-based pH sensors demonstrated a robust response to pH changes, and when tested with BCC circuits, they showed that it was possible to quantize based on pH when transmitting data through the human body. This study successfully developed a novel method for SiNW fabrication and integration into BCC circuits, which could lead to improvements in the reliability and efficiency of implantable medical sensors. The findings demonstrate significant potential for bioelectronic applications and real-time biochemical monitoring.


Asunto(s)
Reflujo Gastroesofágico , Nanocables , Humanos , Nanocables/química , Silicio/química , Reproducibilidad de los Resultados , Prótesis e Implantes , Concentración de Iones de Hidrógeno , Comunicación
19.
Sensors (Basel) ; 24(16)2024 Aug 22.
Artículo en Inglés | MEDLINE | ID: mdl-39205144

RESUMEN

Drones have become essential tools across various industries due to their ability to provide real-time data and perform automated tasks. However, integrating multiple sensors on a single drone poses challenges such as payload limitations and data management issues. This paper proposes a comprehensive system that leverages advanced deep learning techniques, specifically an attention-based generative adversarial network (GAN), to address data scarcity in drone-collected time-series sensor data. By adjusting sensing frequency based on operational conditions while maintaining data resolution, our system ensures consistent and high-quality data collection. The spatiotemporal The attention mechanism within the GAN enhances the generation of synthetic data, filling gaps caused by reduced sensing frequency with realistic data. This approach improves the efficiency and performance of various applications, such as precision agriculture, environmental monitoring, and surveillance. The experimental results demonstrated the effectiveness of our methodology in extending the operational range and duration of drones and providing reliable augmented data utilizing a variety of evaluation metrics. Furthermore, the superior performance of the proposed system was verified by comparing it with various comparative GAN models.

20.
J Clin Nurs ; 2024 Jul 29.
Artículo en Inglés | MEDLINE | ID: mdl-39072827

RESUMEN

AIMS: To describe and compare nurses' awareness of, attitudes toward, and participation in advance care planning, as well as related facilitators and challenges, in four types of healthcare settings. DESIGN: A cross-sectional descriptive study. METHODS: Four hundred and ninety-eight registered nurses from tertiary, secondary and primary healthcare institutions, along with long-term care centres in South Korea, participated in an investigator-developed online survey. The collected data were analysed using descriptive statistics, chi-squared test, one-way ANOVA, and binary logistic regression. RESULTS: Participants were on average 30.6 ± 7.3 years old, mostly female (95.4%), employed as staff nurses (95.4%), held bachelor's degrees or higher (84.1%), and had worked for less than 5 years at their current institutions (69.7%). Overall, 49% of the participants were familiar with advance care planning. While most participants supported nurse involvement in advance care planning with patients and surrogates, fewer were willing to engage or recommend it. Less than half were actively engaged in advance care planning practices. A notable challenge was the lack of time due to excessive workload. Compared to those from tertiary healthcare institutions, participants from secondary and primary healthcare institutions and long-term care centres were less likely to be aware of advance care planning. Participants from secondary and primary healthcare institutions had lower odds of checking for the presence of advance directives and the physician orders for life-sustaining treatment. CONCLUSION: Nurses demonstrated low awareness and participation in advance care planning. Nurses' insufficient time and competency to conduct advance care planning in their practice should be addressed. IMPLICATIONS FOR THE PROFESSION AND/OR PATIENT CARE: Educational programs, initiatives (e.g. guidelines, position statements) and legal and policy-level efforts (e.g. nurse staffing, role clarification, reimbursement) are crucial to incorporate advance care planning into routine nursing practice. IMPACT: What problem did the study address? Nurses play an important role in advance care planning; however, limited is understood about their readiness and involvement in such practices. What were the main findings? Nurses' awareness of advance care planning practices and their participation in such practices is low across care settings. Although nurses have a positive attitude toward advance care planning, there are challenges (e.g. insufficient time to conduct advance care planning discussions and lack of relevant knowledge and skills) that impede their participation in practice. Where and on whom will the research have an impact? This study may serve as a foundation for nursing societies in countries, where advance care planning is emerging, to discuss strategies to increase nurses' competency in advance care planning and promote their participation in the practice. REPORTING METHOD: The STROBE checklist was followed. PATIENT OR PUBLIC CONTRIBUTION: No patient or public contribution.

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