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1.
Front Genet ; 13: 821832, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35559031

RESUMO

The T and B cell repertoire make up the adaptive immune system and is mainly generated through somatic V(D)J gene recombination. Thus, the VJ gene usage may be a potential prognostic or predictive biomarker. However, analysis of the adaptive immune system is challenging due to the heterogeneity of the clonotypes that make up the repertoire. To address the heterogeneity of the T and B cell repertoire, we proposed a novel ensemble feature selection approach and customized statistical learning algorithm focusing on the VJ gene usage. We applied the proposed approach to T cell receptor sequences from recovered COVID-19 patients and healthy donors, as well as a group of lung cancer patients who received immunotherapy. Our approach identified distinct VJ genes used in the COVID-19 recovered patients comparing to the healthy donors and the VJ genes associated with the clinical response in the lung cancer patients. Simulation studies show that the ensemble feature selection approach outperformed other state-of-the-art feature selection methods based on both efficiency and accuracy. It consistently yielded higher stability and sensitivity with lower false discovery rates. When integrated with different classification methods, the ensemble feature selection approach had the best prediction accuracy. In conclusion, the proposed novel approach and the integration procedure is an effective feature selection technique to aid in correctly classifying different subtypes to better understand the signatures in the adaptive immune response associated with disease or the treatment in order to improve treatment strategies.

2.
Front Cell Dev Biol ; 10: 866491, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35573695

RESUMO

The evolutionarily conserved Hedgehog (Hh) signaling plays a critical role in embryogenesis and adult tissue homeostasis. Aberrant Hh signaling often leads to various forms of developmental anomalies and cancer. Since altered microRNA (miRNA) expression is associated with developmental defects and tumorigenesis, it is not surprising that several miRNAs have been found to regulate Hh signaling. However, these miRNAs are mainly identified through small-scale in vivo screening or in vitro assays. As miRNAs preferentially reduce target gene expression via the 3' untranslated region, we analyzed the effect of reduced expression of core components of the Hh signaling cascade on downstream signaling activity, and generated a transgenic Drosophila toolbox of in vivo miRNA sensors for core components of Hh signaling, including hh, patched (ptc), smoothened (smo), costal 2 (cos2), fused (fu), Suppressor of fused (Su(fu)), and cubitus interruptus (ci). With these tools in hand, we performed a genome-wide in vivo miRNA overexpression screen in the developing Drosophila wing imaginal disc. Of the twelve miRNAs identified, seven were not previously reported in the in vivo Hh regulatory network. Moreover, these miRNAs may act as general regulators of Hh signaling, as their overexpression disrupts Hh signaling-mediated cyst stem cell maintenance during spermatogenesis. To identify direct targets of these newly discovered miRNAs, we used the miRNA sensor toolbox to show that miR-10 and miR-958 directly target fu and smo, respectively, while the other five miRNAs act through yet-to-be-identified targets other than the seven core components of Hh signaling described above. Importantly, through loss-of-function analysis, we found that endogenous miR-10 and miR-958 target fu and smo, respectively, whereas deletion of the other five miRNAs leads to altered expression of Hh signaling components, suggesting that these seven newly discovered miRNAs regulate Hh signaling in vivo. Given the powerful effects of these miRNAs on Hh signaling, we believe that identifying their bona fide targets of the other five miRNAs will help reveal important new players in the Hh regulatory network.

3.
Math Biosci Eng ; 19(6): 5576-5590, 2022 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-35603369

RESUMO

The precise segmentation of tumor regions plays a pivotal role in the diagnosis and treatment of brain tumors. However, due to the variable location, size, and shape of brain tumors, the automatic segmentation of brain tumors is a relatively challenging application. Recently, U-Net related methods, which largely improve the segmentation accuracy of brain tumors, have become the mainstream of this task. Following merits of the 3D U-Net architecture, this work constructs a novel 3D U-Net model called SGEResU-Net to segment brain tumors. SGEResU-Net simultaneously embeds residual blocks and spatial group-wise enhance (SGE) attention blocks into a single 3D U-Net architecture, in which SGE attention blocks are employed to enhance the feature learning of semantic regions and reduce possible noise and interference with almost no extra parameters. Besides, the self-ensemble module is also utilized to improve the segmentation accuracy of brain tumors. Evaluation experiments on the Brain Tumor Segmentation (BraTS) Challenge 2020 and 2021 benchmarks demonstrate the effectiveness of the proposed SGEResU-Net for this medical application. Moreover, it achieves DSC values of 83.31, 91.64 and 86.85%, as well as Hausdorff distances (95%) of 19.278, 5.945 and 7.567 for the enhancing tumor, whole tumor, and tumor core on BraTS 2021 dataset, respectively.


Assuntos
Neoplasias Encefálicas , Processamento de Imagem Assistida por Computador , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/patologia , Humanos , Processamento de Imagem Assistida por Computador/métodos , Aprendizagem , Redes Neurais de Computação , Semântica
4.
Exp Eye Res ; 220: 109082, 2022 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-35513040

RESUMO

Retinal ganglion cell (RGC) death is the direct cause of several optic neuropathies. Several studies have reported that the loss of p66Shc ameliorates neuronal injury and vascular abnormalities in ischemia-reperfusion (I/R) injury. However, whether p66Shc is involved in the loss of RGC remains unclear. Therefore, this study aimed to investigate the function of p66Shc due to retinal ischemia in mice. The retinal I/R model was constructed after an intravitreal injection of recombinant adeno-associated viruses (rAAV-EGFP or rAAV-p66Shc-EGFP) for 4 weeks. The expression of p66Shc was detected by western blotting, quantitative real-time polymerase chain reaction, and immunofluorescence staining. The survival of RGCs was determined using immunofluorescence staining. Retinal function was analyzed based on electroretinogram (ERG) findings. Retinal cell apoptosis was detected by TdT-mediated dUTP nick-end labeling staining. The protein expressions of Akt, phospho-Akt, Bax, and PARP were analyzed by western blotting. After rAAVs were successfully transfected, enhanced green fluorescent protein was expressed in all retinal cell layers, and the level of p66Shc after I/R injury was successfully reduced. We found that inhibition of p66Shc expression remarkably decreased the death of RGCs and prevented the loss of ERG a- and b-wave amplitudes caused by retinal ischemia. Mechanistically, downregulation of p66Shc resulted in reduced Bax, whereas increased phospho-Akt and PARP. Taken together, our study revealed that p66Shc acts through the Akt pathway to protect RGCs from retinal I/R injury-induced apoptosis and retinal dysfunction, making p66Shc a possible therapeutic target for glaucoma treatment.

5.
Sci Rep ; 12(1): 7262, 2022 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-35508689

RESUMO

Next-generation site-specific cysteine-based antibody-drug-conjugates (ADCs) broaden therapeutic index by precise drug-antibody attachments. However, manufacturing such ADCs for clinical validation requires complex full reduction and reoxidation processes, impacting product quality. To overcome this technical challenge, we developed a novel antibody manufacturing process through cysteine (Cys) metabolic engineering in Chinese hamster ovary cells implementing a unique cysteine-capping technology. This development enabled a direct conjugation of drugs after chemoselective-reduction with mild reductant tris(3-sulfonatophenyl)phosphine. This innovative platform produces clinical ADC products with superior quality through a simplified manufacturing process. This technology also has the potential to integrate Cys-based site-specific conjugation with other site-specific conjugation methodologies to develop multi-drug ADCs and exploit multi-mechanisms of action for effective cancer treatments.


Assuntos
Antineoplásicos , Imunoconjugados , Animais , Anticorpos , Antineoplásicos/uso terapêutico , Células CHO , Cricetinae , Cricetulus , Cisteína , Dissulfetos , Imunoconjugados/farmacologia , Imunoconjugados/uso terapêutico , Engenharia Metabólica
6.
Nat Mater ; 2022 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-35484330

RESUMO

In principle, porous physisorbents are attractive candidates for the removal of volatile organic compounds such as benzene by virtue of their low energy for the capture and release of this pollutant. Unfortunately, many physisorbents exhibit weak sorbate-sorbent interactions, resulting in poor selectivity and low uptake when volatile organic compounds are present at trace concentrations. Herein, we report that a family of double-walled metal-dipyrazolate frameworks, BUT-53 to BUT-58, exhibit benzene uptakes at 298 K of 2.47-3.28 mmol g-1 at <10 Pa. Breakthrough experiments revealed that BUT-55, a supramolecular isomer of the metal-organic framework Co(BDP) (H2BDP = 1,4-di(1H-pyrazol-4-yl)benzene), captures trace levels of benzene, producing an air stream with benzene content below acceptable limits. Furthermore, BUT-55 can be regenerated with mild heating. Insight into the performance of BUT-55 comes from the crystal structure of the benzene-loaded phase (C6H6@BUT-55) and density functional theory calculations, which reveal that C-H···X interactions drive the tight binding of benzene. Our results demonstrate that BUT-55 is a recyclable physisorbent that exhibits high affinity and adsorption capacity towards benzene, making it a candidate for environmental remediation of benzene-contaminated gas mixtures.

7.
Artigo em Inglês | MEDLINE | ID: mdl-35412976

RESUMO

Small and cluttered objects are common in real-world which are challenging for detection. The difficulty is further pronounced when the objects are rotated, as traditional detectors often routinely locate the objects in horizontal bounding box such that the region of interest is contaminated with background or nearby interleaved objects. In this paper, we first innovatively introduce the idea of denoising to object detection. Instance-level denoising on the feature map is performed to enhance the detection to small and cluttered objects. To handle the rotation variation, we also add a novel IoU constant factor to the smooth L1 loss to address the long standing boundary problem, which to our analysis, is mainly caused by the periodicity of angular (PoA) and exchangeability of edges (EoE). By combing these two features, our proposed detector is termed as SCRDet++. Extensive experiments are performed on large aerial images public datasets DOTA, DIOR, UCAS-AOD as well as natural image dataset COCO, scene text dataset ICDAR2015, small traffic light dataset BSTLD and our newly released S 2TLD by this paper. The results show the effectiveness of our approach. The released dataset S 2TLD is made public available, which contains 5,786 images with 14,130 traffic light instances across five categories.

8.
Chemosphere ; 301: 134738, 2022 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-35489451

RESUMO

Although the benefits of biochar amendment for heavy metal(loid) immobilization in soil have been widely recognized, its migration in soil and the resultant effects on the risk of downward migration of metal(loid)s are still poorly understood. In this study, based on biochar derived dissolved organic matter (DOM), excitation-emission matrix coupled with parallel factor analysis (EEM-PARAFAC) technique was employed to trace biochar migration within one year in 0-100 cm soil profiles in the field. The vertical co-migration of Pb, Cu and As was also analyzed. With biochar amended, DOM, humification index (HIX) and biological index (BIX) in 0-60 cm soil profiles increased significantly, while pH only increased in the topsoil. The identified water-extracted DOM components showed that biochar could enhance the content of fulvic acids and humic acids in soil DOM and biochar might migrate downward to 60 cm soil profiles. Furthermore, toluene/methanol-extracted DOM also confirmed the migration extent of biochar, which was more suitable to trace biochar migration because of its high resistance to the long-term ageing in the field. Moreover, we found that biochar reduced the content of Cu in 0-60 cm soil profiles, but increased the available Pb and As in the 20-40 cm soil layers. The Pearson's correlation study confirmed a strong correlation (0.568**≤R ≤ 0.803**) between the content of heavy metal(loid)s and humic-like components of soil DOM, which suggested that biochar co-migrated with Pb, Cu and As, and the potential environmental risks of biochar should be fully evaluated while it was applied for soil metal(loid) remediation.

10.
ACS Nano ; 16(3): 4823-4830, 2022 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-35243860

RESUMO

Electric double layer transistors (EDLTs) based on C60 single crystals and ionic liquid gates display pronounced peaks in sheet conductance versus gate-induced charge. Sheet conductance is maximized at electron densities near 0.5 e/C60 and is suppressed near 1 e/C60. The conductance suppression depends markedly on the choice of ionic liquid cation, with small cations favoring activated transport and essentially a complete shutdown of conductance at ∼1 e/C60 and larger cations favoring band-like transport, higher overall conductances at all charge densities up to 1.7 e/C60, and weaker suppression at 1 e/C60. Displacement current measurements on C60 EDLTs with small cations show clear evidence of sub-band filling at 1 e/C60, which correlates very well with the minimum in the C60 sheet conductance. Overall, the data suggest a significant Mott-Hubbard-like energy gap opens up in the surface density of states for C60 crystals gated with small cations. The causes of this energy gap may include both electron-electron repulsion and electron-cation attraction at the crystal/ionic liquid interface. The energy gap suppresses the insulator-to-metal transition in C60 EDLTs, but it can be manipulated by choice of electrolyte.

11.
J Am Chem Soc ; 144(11): 4734-4738, 2022 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-35258291

RESUMO

Superelectrophilic silylium/arenium ions are shown to be highly effective H/D exchange promoters for the exhaustive deuteration of electron-deficient aryl halides. Several of the resulting perdeuterated aryl halides have been previously inaccessible with existing deuterium-labeling procedures. Using inexpensive C6D6 as the deuterium source, excellent degrees of deuterium incorporation were achieved under ambient reaction conditions. Importantly, the perdeuteration remains unaffected on multigram scale, even at a reduced catalyst loading of 0.1 mol %. By this method, otherwise expensive or noncommercially available NMR solvents such as 1,2-dichloro- and 1,2-difluorobenzene can be prepared.


Assuntos
Deutério , Catálise , Íons , Espectroscopia de Ressonância Magnética , Solventes
12.
Balkan Med J ; 39(2): 107-114, 2022 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-35330555

RESUMO

Background: Rapamycin was shown to reduce transforming growth factor ß1 (TGF-ß1) expression, inhibit the Mammalian target of rapamycin function, and prevent TGF-ß1-induced pulmonary fibrosis. Rapamycin-eluting stents (RES) were successfully used to prevent coronary artery restenosis. Urethral stricture is one of the most challenging problems in urology. Thus, combining the pharmacological effects of rapamycin and the mechanical support of the stent on the urethra may prevent urethral stricture formation. However, the use of RES for urethral stricture treatment has not been studied. Aims: To observe the effects of RES in urethral stricture in a rabbit model. Study Design: Animal experimentation. Methods: Twenty adult male New Zealand rabbits were randomly divided into control, urethral stricture model, bare-metal stent, and RES groups. The rabbits in the control group underwent urethroscopy alone without electrocoagulation. The rabbit model of urethral stricture was established by electrocoagulation using a self-made electrocoagulation device under direct vision using ureteroscopy. After model establishment, the rabbits in the bare-metal stent and RES groups received stent placement by ureteroscopy. On day 30, retrograde urethrography was performed to assess urethral stricture formation, ureteroscopy to remove the stents, and histological examinations to assess the degree of fibrosis. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis were used to evaluate the expression levels of TGF-ß1, Smad3, and matrix metalloproteinase 1 (MMP1). Results: Urethral stricture formation was seen in the model group, whereas not in the bare-metal stent group. The bare-metal stents did not displace but were difficult to remove. In the RES group, RES was dislodged in itself at postoperative day 27 in one rabbit, whereas successfully removed by ureteroscopy in the remaining four rabbits, and urethral stricture formation was not seen on retrograde urethrography after stent removal. Histological examination revealed a large number of dense fibroblasts and blue-stained collagen fibers in the bare-metal stent group, whereas the number of fibroblasts and collagen fibers under the mucosa was reduced in the RES group. RT-qPCR and Western blot analyses showed that the messenger ribonucleic acid (mRNA) and protein expression of TGF-ß1and Smad3 was significantly decreased, and mRNA and protein expression of MMP1 was significantly increased in the RES group than that in the model ((P < 0.001) and bare-metal stent groups (P < 0.001). Conclusion: RES can effectively prevent electrocoagulation-induced urethral stricture in rabbits. The mechanism may be related to the effect of rapamycin on inhibiting TGF-ß1 and Smad3 expression and promoting MMP1 expression in urethral tissues.


Assuntos
Stents Farmacológicos , Estreitamento Uretral , Animais , Colágeno , Stents Farmacológicos/efeitos adversos , Humanos , Masculino , Mamíferos , Metaloproteinase 1 da Matriz , RNA Mensageiro , Coelhos , Sirolimo/farmacologia , Sirolimo/uso terapêutico , Stents , Fator de Crescimento Transformador beta1 , Estreitamento Uretral/metabolismo , Estreitamento Uretral/patologia , Estreitamento Uretral/prevenção & controle
13.
Angew Chem Int Ed Engl ; : e202203347, 2022 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-35344257

RESUMO

A regioselective addition of alkynylsilanes across unactivated, terminal alkenes is reported. The reaction is initiated by the capture of a sterically unhindered silylium ion by a silylated phenylacetylene derivative to form a bis(silylated) ketene-like carbocation. This in situ-generated key intermediate is the actual catalyst that maintains the catalytic cycle by a series of electrophilic addition reactions of silylium ions and ß-silicon-stabilized carbocations. The computed reaction mechanism is fully consistent with the experimental findings. This unprecedented two-component carbosilylation establishes a C(sp3 )-C(sp) bond and a C(sp3 )-Si bond in atom-economic fashion.

14.
Water Res ; 216: 118297, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35325825

RESUMO

To extract lithium from salt lake brine involves a process of separation and concentration. After separating lithium from brine, the lithium ion concentration is generally a few hundred mg/L which is far below the required 20-30 g/L (as Li+) before precipitation as lithium carbonate. The concentration step of a lithium enriched brine is crucial but highly energy-intensive. Spontaneous forward osmosis (FO) technology offers the possibility for concentrating lithium ions with low energy. Because the concentrating process involves both feed and draw solution with very high salinity, it is highly desirable to have a high performance FO membrane with a low structural parameter as well as a high rejection to ions. In this work, thin polyethylene separator supported FO (PE-FO) membranes were prepared and post-treated stepwise with benzyl alcohol (BA) and hydraulic compaction. The effect of the post-treatment on the FO performance was systematically analyzed. Excellent FO performance was achieved: the water flux and reverse salt flux selectivity were 66.3 LMH and 5.25 L/g, respectively, when the active layer is oriented towards the 0.5 M NaCl draw solution with deionized water as the feed. To the best of our knowledge, this FO flux is the highest ever reported in the open literature under similar test conditions. Applied in concentrating lithium enriched brine, the membrane showed superior water flux using saturated MgCl2 as draw solution. A new FO model was established to simulate the water flux during the concentration process with good agreement with the experimental results. The promising results using PE-FO membrane for lithium enrichment opens a new frontier for the potential application of FO membranes.

15.
Nano Lett ; 22(6): 2251-2260, 2022 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-35254836

RESUMO

Current surgical single modality treatments for hepatocellular carcinoma (HCC) were restricted by recurrence, blood loss, significant trauma, and poor prognostic. Although multidisciplinary strategies for HCC treatment have been highly recommended by the clinical guidelines, there was limited choice of materials and treatments. Herein, we reported an in situ formed magnetic hydrogel with promising bioapplicable thermal-responsiveness, strong adhesion in wet conditions, high magnetic hyperthermia, and biocompatibility, leading to efficient HCC multidisciplinary treatment including postoperative treatment and transarterial embolization therapy. In vivo results indicated that this hydrogel could reduce the postoperative recurrence rate. The hemostatic ability of the thermal-responsive hydrogel was further demonstrated in both the liver scratch model and liver tumor resection. Computed tomography imaging suggested that the hydrogel could completely embolize the arterial vessels of rabbit liver tumor by vascular intervention operation, which could serve as multidisciplinary responsive materials to external magnetic field and body temperature for HCC treatment.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Animais , Carcinoma Hepatocelular/diagnóstico por imagem , Carcinoma Hepatocelular/patologia , Carcinoma Hepatocelular/terapia , Hepatectomia/métodos , Hidrogéis/uso terapêutico , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/terapia , Fenômenos Magnéticos , Coelhos
16.
J Hazard Mater ; 432: 128647, 2022 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-35305412

RESUMO

As a new type of environmental pollutant, environmental antibiotic residues have attracted widespread attention, and the degradation and removal of antibiotics has become an engaging topic for scholars. In this paper, Novozym 51003 industrialized laccase and syringaldehyde were combined to degrade sulfonamides in aquaculture wastewater. Design Expert10 software was used for multiple regression analysis, and a response surface regression model was established to obtain the optimal degradation parameters. In the actual application, the degradation system could maintain a stable performance within 9 h, and timely supplement of the mediator could achieve a better continuous degradation effect. Low concentrations of heavy metals and organic matter would not significantly affect the degradation performance of the laccase-mediator system, making the degradation system suitable for a wide range of water quality. Enzymatic reaction kinetics demonstrated a strong affinity of sulfadiazine to the substrate. Ten degradation products were speculated using high-resolution mass spectrum based on the mass/charge ratios and the publication results. Four types of possible degradation pathways of sulfadiazine were deduced. This work provides a practical method for the degradation and removal of sulfonamide antibiotics in actual sewage.


Assuntos
Lacase , Águas Residuárias , Antibacterianos/química , Aquicultura , Benzaldeídos , Cinética , Lacase/metabolismo , Sulfadiazina , Sulfanilamida , Sulfonamidas/química
17.
Transl Pediatr ; 11(2): 260-269, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35282029

RESUMO

Background: During treatment of acute respiratory failure (ARF) in children, sedation can reduce pain, improve tolerance, and reduce the incidence of adverse events, so selecting an appropriate sedation strategy is very important for improving prognosis and quality of life. Both dexmedetomidine and propofol have good sedative effects, so we investigated the application of these drugs in critically ill children with ARF by literature search and meta-analysis. Methods: We searched Embase, The Cochrane Library, PubMed, Ovid, Clinicaltrials.org, and Google Scholar for randomized controlled trials (RCTs) preferentially but not exclusively, and used RevMan 5.4 to analyze the screened literature. Results: Seven studies were included in the quantitative meta-analysis, with a total of 1,188 patients. There was no significant difference in the effect of dexmedetomidine and propofol on the duration of tracheal intubation in children with ARF [mean difference (MD) =-0.05; 95% confidence interval (CI): (-0.42, 0.32); Z=0.26; P=0.79], but dexmedetomidine sedation could reduce the intensive care unit (ICU) stay in children with ARF [MD =-0.62; 95% CI: (-1.08, -0.16); Z=2.65; P=0.008], and shorten the total hospital stay [MD =-1.94; 95% CI: (-2.63, -1.25); Z=5.48; P<0.00001]. There was no significant effect on mortality between the two groups [odds ratio (OR) =0.48; 95% CI: (0.19, 1.25); Z=1.50; P=0.13]. The incidence rate of bradycardia with dexmedetomidine sedation was higher than with propofol [OR =12.30; 95% CI: (2.28, 66.47); Z=2.92; P=0.004], and the incidence of hypotension was also higher [OR =6.99, 95% CI: (1.22, 39.86); Z=2.19; P=0.03]. Discussion: Compared with propofol, dexmedetomidine can significantly reduce the ICU stay and hospital stay. However, bradycardia and hypotension may occur during the use of dexmedetomidine, which requires close attention and timely intervention.

19.
Sci Adv ; 8(9): eabk3381, 2022 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-35235364

RESUMO

Reflecting light to a predetermined nonspecular direction is an important ability of metasurfaces, which is the basis for a wide range of applications (e.g., beam steering/splitting and imaging). However, anomalous reflection with 100% efficiency has not been achieved at optical frequencies yet, because of losses and/or insufficient nonlocal control of light waves. Here, we propose an all-dielectric quasi-three-dimensional subwavelength structure, consisting of multilayer films and metagratings, to achieve perfect anomalous reflections at optical frequencies. A complex multiple scattering process was stimulated by effectively coupling different Bloch waves and propagating waves, thus offering the metasystem the desired nonlocal control on light waves required by perfect anomalous reflections. Two perfect anomalous reflectors were demonstrated to reflect normally incident 1550-nm light to the 40°/75° directions with absolute efficiencies of 99%/99% in design (98%/88% in experiment). Our results pave the way toward realizing optical metadevices with desired high efficiencies in realistic applications.

20.
J Artif Organs ; 2022 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-35347487

RESUMO

Artificial cardiovascular devices, such as vascular stents, artificial valves, and artificial hearts, can rebuild human cardiovascular functionalities via rebuilding the blood flow passing through these devices. To evaluate the red blood cells (RBCs) damage induced by a non-physiological blood flow in these devices, many hemolysis models have been proposed, of which the most popular one is a power function model. However, it was found that the newly obtained experimental data often did not match the existing power function model. In addition, the experimental period was usually short and the summarized power function model cannot reflect the RBCs damage after long-term exposure to shear stress. To address this issue, in this study a shear device was established on a torque rheometer; the changes of plasma free hemoglobin (FHB) of sheep blood under the shear stress from 10 to 70 Pa and exposure time from 5 to 30 min were recorded and compared. The results showed that as the shear stress and exposure time increased, FHB also increased, but the increase rate gradually decreased. As a result, after undergoing high shear stress or a long period of exposure time, FHB eventually became stable. Obviously, the existing power function model cannot describe this FHB change. In the current study, we used a sigmoidal logistic function model to describe the FHB increment upon the increase of shear stress and long exposure time. The results showed that the proposed model can provide better predictions of hemolysis, particularly in these cases under long exposure time.

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