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1.
BMC Cardiovasc Disord ; 21(1): 334, 2021 07 07.
Article in English | MEDLINE | ID: mdl-34233618

ABSTRACT

BACKGROUND: Previous studies have validated the capability of SYNTAX score (SS) and clinical SYNTAX score (CSS) in the prediction of clinical outcomes in patients who have undergone PCI; however, studies on comparison of these two scoring systems in Chinese population have been sparse. METHODS: To study the ability of SS and CSS in prediction of clinical outcomes of Chinese patients underwent percutaneous coronary intervention (PCI). We retrospectively calculated SS and CSS for 547 Chinese patients from a single center who underwent PCI. Patients were stratified into tertiles according to their SS and CSS. We compared the 2-year clinical outcomes in these patients stratified separately by SS and CSS tertiles. RESULTS: The incidence of major adverse cardiac and cerebro-vascular events (MACCE) was the highest in patients with SSHIGH (13.5%), comparing to 6.8% in SSMED and 0% in SSLOW (p < 0.0001). The Cox multivariable analysis showed that the SS and CSS were both strong independent predictors for MACCE [1.100 (1.069-1.133), 1.017 (1.010-1.025), both p < 0.0001]. The receiver operating characteristic (ROC) curves showed the areas-under-the-curves for all-cause death by CSS was slightly larger comparing to SS but not significantly (AUC SS, 0.64; AUC CSS, 0.71; p = 0.23). CONCLUSION: We concluded that both the SS and CSS were capable of risk stratification of clinical outcomes in all-comers population as well as in low and moderate risk Chinese patients undergoing PCI with CSS showing slightly better advantage.


Subject(s)
Acute Coronary Syndrome/therapy , Coronary Angiography , Coronary Artery Disease/therapy , Decision Support Techniques , Percutaneous Coronary Intervention , Acute Coronary Syndrome/diagnostic imaging , Acute Coronary Syndrome/mortality , Aged , China , Coronary Artery Disease/diagnostic imaging , Coronary Artery Disease/mortality , Drug-Eluting Stents , Female , Humans , Male , Middle Aged , Percutaneous Coronary Intervention/adverse effects , Percutaneous Coronary Intervention/instrumentation , Percutaneous Coronary Intervention/mortality , Predictive Value of Tests , Reproducibility of Results , Retrospective Studies , Risk Assessment , Risk Factors , Time Factors , Treatment Outcome
2.
Nanomaterials (Basel) ; 10(8)2020 Aug 07.
Article in English | MEDLINE | ID: mdl-32784585

ABSTRACT

The notion of an effective longitudinal coherence length with its value much greater than λ2/(2Δλ) has been adopted in small-angle X-ray scattering communities for years, where λ and Δλ denote the incident wavelength and its spread, respectively. Often the implications of the effective longitudinal coherence length do not even enter considerations in the designing and data treatment of small-angle scattering experiments. In this work, conventional transmission small-angle X-ray scattering (tSAXS) was performed to reveal a clear angular dependence on effective longitudinal coherence length. The measured values of effective longitudinal coherence length can be as high as one millimeter, whereas the value of calculated λ2/(2Δλ) is in nanometers.

3.
Article in English | MEDLINE | ID: mdl-31277959

ABSTRACT

OBJECTIVE: The aim of this study was to investigate the imaging features of salivary duct carcinoma (SDC) with multiphase contrast-enhanced computed tomography (CECT) and to compare them with those of mucoepidermoid carcinoma (MEC), adenoid cystic carcinoma (ACC), and acinic cell carcinoma. STUDY DESIGN: A total of 63 patients with histologically diagnosed salivary gland malignancies underwent preoperative multiphase CECT. Clinical information, location, size, mass pattern, enhancement pattern, borders, invasion of adjacent tissues, and lymph node metastasis were evaluated. Computed tomography (CT) number attenuation patterns were calculated. RESULTS: SDCs were significantly more common in males and in the parotid gland (P ≤ .018). They were more likely to invade into adjacent tissues and metastasize to lymph nodes (P ≤ .032). Six SDCs (66.7%) had comedonecrosis, as detected on histopathologic examination, and 3 lesions presented cribriform necrosis on CECT. CT numbers during delayed-phase scanning were significantly higher in SDC than in ACC (P = .031). Significant differences were discovered between MEC and ACC for CT numbers during arterial-phase scanning (P = .047) and in the ratio of CT numbers (P = .018). CONCLUSIONS: SDC exhibits some specific CT features, and multiphase CECT imaging is useful in the differential diagnosis of salivary gland malignancies.


Subject(s)
Carcinoma, Adenoid Cystic , Carcinoma, Mucoepidermoid , Salivary Gland Neoplasms , Carcinoma, Adenoid Cystic/diagnostic imaging , Carcinoma, Mucoepidermoid/diagnostic imaging , Cell Differentiation , Female , Humans , Male , Salivary Ducts/diagnostic imaging , Salivary Gland Neoplasms/diagnostic imaging , Tomography, X-Ray Computed
4.
Talanta ; 194: 308-313, 2019 Mar 01.
Article in English | MEDLINE | ID: mdl-30609535

ABSTRACT

Lipid droplets were found to be involved in many organism activities. Here, a lipid droplets-targeted near-infrared fluorescence probe (named XHZ) for ratiometric detection of endogenous hypochlorous acid/hypochlorite (HClO/ClO-) in living cells was developed, which was constructed by a coumarin moiety and a malononitrile derivative. XHZ could detect HClO/ClO- with high selectivity and sensitivity in a ratiometric manner based on FRET (Förster Resonance Energy Transfer) mechanism. The two well-resolved emission (470/672 nm) bands could ensure accurate detection of HClO/ClO- in vitro as well as in vivo. XHZ was successfully used for ratiometric fluorescence imaging of exogenous and endogenous HClO/ClO- in RAW264.7 cells. A good linear relationship between the fluorescence intensity ratios of the two emissions and HClO/ClO- concentrations from 0 to 40 µM was obtained. Importantly, XHZ could localize mainly in lipid droplets of RAW264.7 cells. To the best of our knowledge, XHZ is the first lipid droplets-targeted ratiometric fluorescence probe for HClO/ClO-.


Subject(s)
Fluorescent Dyes/metabolism , Hypochlorous Acid/metabolism , Lipid Droplets/metabolism , Animals , Cell Survival , Coumarins/chemistry , Fluorescent Dyes/chemistry , Lipid Droplets/chemistry , Mice , Optical Imaging , RAW 264.7 Cells
6.
Appl Phys Lett ; 115(2)2019.
Article in English | MEDLINE | ID: mdl-32165739

ABSTRACT

Here, we present a method for measuring dimensions of nanostructures using specular reflection of electrons from an electronically opaque surface. Development of this method has been motivated by measurement needs of the semiconductor industry1-4, and it can also be more broadly applicable to any periodic, pseudo-periodic or statistically stationary nanostructures or nanopattern on an opaque substrate. In prior work5,6, it was demonstrated through the presentation of proof of concept experiments and simulated examples that Reflective Small Angle Electron Scattering (RSAES) can meet certain dimensional metrology requirements of the semiconductor industry. In RSAES, an entire reflected scattering pattern is measured, with the scattered electrons being of primary interest. Later, in the process of further simulating RSAES, it was serendipitously discovered that dimensional measurement using reflected electrons might be greatly simplified by Electron Reflectometry (ER), whereby the intensity of the specularly reflected electron beam is measured and the scattered beams ignored.7 This innovation may allow faster and cheaper development and deployment or at the very least provide an alternate pathway to exploit the phenomenon of reflected electrons for dimensional measurement. Here we discuss how ER complements existing dimensional measurement techniques, show simulated applications with an emphasis an defect detection and line-width measurements.

7.
Appl Phys Lett ; 111(12)2017 Sep.
Article in English | MEDLINE | ID: mdl-29242646

ABSTRACT

Features sizes in integrated circuits (ICs) are often at the scale of 10 nm and are ever shrinking. ICs appearing in today's computers and hand held devices are perhaps the most prominent examples. These smaller feature sizes demand equivalent advances in fast and accurate dimensional metrology for both development and manufacturing. Techniques in use and continuing to be developed include X-ray based techniques, optical scattering and of course the electron and scanning probe microscopy techniques. Each of these techniques have their advantages and limitations. Here the use of small angle electron beam scattering measurements in a reflection mode (RSAES) to characterize the dimensions and the shape of nanostructures on flat and opaque substrates is demonstrated using both experimental and theoretical evidence. In RSAES, focused electrons are scattered at angles smaller than 1° with the assistance of electron optics typically used in transmission electron microscopy. A proof-of-concept experiment is combined with rigorous electron reflection simulations to demonstrate the efficiency and accuracy of RSAES as a method of non-destructive measurement of shapes of features less than 10 nm in size on flat and opaque substrates.

8.
Anal Chim Acta ; 950: 178-183, 2017 Jan 15.
Article in English | MEDLINE | ID: mdl-27916123

ABSTRACT

A mitochondria-targeted fluorescence probe (CPBT) for ratiometric detection of endogenous hypochlorite in the living cells was developed. CPBT could detect hypochlorite with high selectivity and sensitivity in a ratiometric manner based on FRET mechanism. In absence of hypochlorite, when CPBT was excited with absorption maximum wavelength of the donor moiety, it showed the emission of acceptor moiety because of FRET process. However, in the presence of hypochlorite, the reaction of CC double bond with hypochlorite interrupted the conjugation system resulting in the inhibition of FRET process and the emission of the donor moiety. The two well-resolved emission bands can ensure accurate detection of hypochlorite. A good linear relationship between the fluorescence intensity ratios of the two emissions and the ClO- concentrations in the range from 41.8 nM (detection limit) to 12.5 µM was established. Importantly, CPBT could localize mainly in the mitochondria of RAW264.7 cells. CPBT was successfully used to fluorescence ratiometric imaging of endogenous hypochlorite in RAW264.7 cells.


Subject(s)
Fluorescent Dyes , Hypochlorous Acid/analysis , Mitochondria/chemistry , Animals , Fluorescence Resonance Energy Transfer , Mice , Microscopy, Fluorescence , RAW 264.7 Cells
9.
Sci Rep ; 6: 25315, 2016 05 03.
Article in English | MEDLINE | ID: mdl-27137791

ABSTRACT

Bisulfite plays crucial roles in diverse physiological processes. Therefore, the efficient detection of bisulfite is very important. In this study, we report a colorimetric and ratiometric fluorescent probe (CPT) with a large Stokes shift (162 nm) for bisulfite (HSO3(-)) based FRET mechanism. The probe can quantitatively detect HSO3(-) with low detection limit (45 nM) and high specificity over other common anions and biothiols. A nucleophilic addition reaction was proposed for the sensing mechanism, which was confirmed by HRMS spectra. The test strips of the probe were made and used easily. Moreover, probe CPT was used to ratiometric fluorescent imaging of exogenous and endogenous HSO3(-) in living cells.


Subject(s)
Colorimetry/methods , Fluorescence Resonance Energy Transfer/methods , Fluorescent Dyes/metabolism , Optical Imaging/methods , Sulfites/analysis
10.
Article in English | MEDLINE | ID: mdl-26142177

ABSTRACT

A novel fluorescence probe Rhodamine-Ethanediamine-Iodomethane (REI) was successfully prepared to serve as an efficient sensing platform for H(+) with fully reversibility mainly between the pH 4.2 and 7.2 in simple buffer solution. The introduction of quaternary ammonium salt with positive charge can not only manage to increase the solubility and sensitivity of probe REI, but also avoid the "alkalizing effect" due to charge-induced effect compared to the reference probe Rhodamine-Ethanediamine (RE). In particular, probe REI was well used for monitoring the weak acid pH fluctuations in lysosome of the live HeLa cells due to its excellent biological properties, including low cytotoxicity, high selectivity, good sensitivity and membrane permeability.


Subject(s)
Lysosomes/chemistry , Quaternary Ammonium Compounds/chemistry , Water/chemistry , Fluorescence , Fluorescent Dyes , HeLa Cells , Humans , Hydrogen-Ion Concentration , Spectrometry, Fluorescence
11.
ACS Nano ; 8(8): 8426-37, 2014 Aug 26.
Article in English | MEDLINE | ID: mdl-25075449

ABSTRACT

The directed self-assembly (DSA) of block copolymers (BCP) is an emerging resolution enhancement tool that can multiply or subdivide the pitch of a lithographically defined chemical or topological pattern and is a resolution enhancement candidate to augment conventional lithography for patterning sub-20 nm features. Continuing the development of this technology will require an improved understanding of the polymer physics involved as well as experimental confirmation of the simulations used to guide the design process. Both of these endeavors would be greatly facilitated by a metrology, which is capable of probing the internal morphology of a DSA film. We have developed a new measurement technique, resonant critical-dimension small-angle X-ray scattering (res-CDSAXS), to evaluate the 3D buried features inside the film. This is an X-ray scattering measurement where the sample angle is varied to probe the 3D structure of the film, while resonant soft X-rays are used to enhance the scattering contrast. By measuring the same sample with both res-CDSAXS and traditional CDSAXS (with hard X-rays), we are able to demonstrate the dramatic improvement in scattering obtained through the use of resonant soft X-rays. Analysis of the reciprocal space map constructed from the res-CDSAXS measurements allowed us to reconstruct the complex buried features in DSA BCP films. We studied a series of DSA BCP films with varying template widths, and the internal morphologies for these samples were compared to the results of single chain in mean-field simulations. The measurements revealed a range of morphologies that occur with changing template width, including results that suggest the presence of mixed morphologies composed of both whole and necking lamella. The development of res-CDSAXS will enable a better understanding of the fundamental physics behind the formation of buried features in DSA BCP films.

12.
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi ; 28(12): 1258-60, 2012 Dec.
Article in Chinese | MEDLINE | ID: mdl-23232516

ABSTRACT

AIM: To study the effects of dexamethasone on the IL-13-induced mCLCA3 and Muc5ac expressions in nasal mucosa of rats, and the role in mucus secretion of allergic rhinitis. METHODS: Thirty SD rats were randomly divided into control group, IL-13 group and dexamethasone group. Expressions of mCLCA3 mRNA and Muc5ac protein in nasal mucosa were detected by RT-PCR and immunohistochemistry, respectively. RESULTS: No mCLCA3 mRNA expression in the nasal mucosa was detected in the control group, while it was 0.319±0.121 in the IL-13 group (P<0.05 vs control group) and 0.144±0.105 in the dexamethasone group (P<0.05 vs IL-13 group). The expression of Muc5ac protein increased in the IL-13 group (1.389±0.499) as compared with the control group (0.300±0.145, P<0.05). After treatment with dexamethasone, the expression of Muc5ac protein was notably lower (0.901±0.390) than that in IL-13 group (P<0.05). CONCLUSION: IL-13 up-regulates the expressions of mCLCA3 mRNA and Muc5ac protein in nasal mucosa, which may play a pivotal role in the mucus overproduction of nasal mucosa. Dexamethasone substantially down-regulates the expressions of mCLCA3 mRNA and Muc5ac protein, which may have an inhibiting effect on mucus overproduction of nasal mucosa.


Subject(s)
Chloride Channels/genetics , Dexamethasone/administration & dosage , Gene Expression/drug effects , Interleukin-13/genetics , Mucin 5AC/genetics , Nasal Mucosa/metabolism , Animals , Chloride Channels/metabolism , Female , Interleukin-13/metabolism , Mucin 5AC/metabolism , Nasal Mucosa/drug effects , Rats , Rats, Sprague-Dawley
13.
Langmuir ; 28(20): 7665-78, 2012 May 22.
Article in English | MEDLINE | ID: mdl-22577835

ABSTRACT

Lithographic feature size requirements have approached a few radius of gyration of photoresist polymers used in thin-film patterning. Furthermore, the feature dimensions are commensurate with the photoacid diffusion length that defines the underlying latent image. Smaller imaging building blocks may enable reduced feature sizes; however, resolution limits are also dependent upon the spatial extent of the photoacid-catalyzed reaction diffusion front and subsequent dissolution mechanism. The reaction-diffusion front was characterized by neutron reflectivity for ccc stereoisomer-purified, deuterium-labeled tert-butoxycarbonyloxy calix[4]resorcinarene molecular resists. The spatial extent of the reaction front exceeds the size of the molecular resist with an effective diffusion constant of (0.13 ± 0.06) nm(2)/s for reaction times longer than 60 s, with the maximum at shorter times. Comparison to a mean-field reaction-diffusion model shows that a photoacid trapping process provides bounds to the spatial and extent of reaction via a reaction-limited mechanism whereas the ratio of the reaction rate to trapping rate constants recovers the effective diffusion peak. Under the ideal step-exposure conditions, surface roughness was observed after either positive- or negative-tone development. However, negative-tone development follows a surface-restructuring mechanism rather than etch-like dissolution in positive-tone development.

14.
Zhonghua Xin Xue Guan Bing Za Zhi ; 40(11): 939-44, 2012 Nov.
Article in Chinese | MEDLINE | ID: mdl-23363676

ABSTRACT

OBJECTIVE: To establish a community-based management model for heart failure patients under the professional guidance of upper first-class hospital staff. METHODS: Two hundreds heart failure (New York Heart Function II-IV) patients aged from 35 to 85 in two communities of Chengdu city were divided into two groups by cluster randomization: the management group and the control group. The community hospital doctors were trained for the evaluation and management of heart failure according standardized guidelines by upper first-class hospital doctors, and responsible for the management of patients in the management group. Meanwhile, the management group patients also received self-care education. Patients in control group were treated by community doctors without special training. Data including the community hospital doctors' knowledge rate of heart failure, positive diagnosis rate, and the rate for standardized medication for heart failure; the patients' knowledge rate of heart failure, the rate of drug compliance, the rate of standardized drug taken for heart failure, the rate of self-care in daily-life, the quality of life, the incidence of cardiovascular events, hospitalization time and cost were compared between the two groups. RESULTS: The community hospital doctors' knowledge rate of heart failure, the related knowledge for prevention and treatment on the causes of heart failure, the positive diagnosis rate, and the rate for standardized medication for heart failure [ß receptor blocker 77.3% (17/22); angiotensin-converting enzyme inhibitors 63.6% (14/22)] were significantly higher than doctors in the control group (all P < 0.05). There were 96 in the management group and 97 in the control group. Data were similar between the two groups at baseline. After (18.5 ± 0.5) months, the patient's knowledge rate of heart failure [100% (96/96) vs. 71.1% (69/97)], the rate of drug compliance [78.1% (75/96) vs. 13.4% (13/97)], the rate of standardized drug taken for heart failure[ß receptor blocker: 75.0% (72/96) vs. 8.2% (8/97); angiotensin-converting enzyme inhibitors: 60.4% (58/96)vs. 10.3% (10/97)], and the rate of self-care in daily-life [salt and food restriction:88.5% (85/96) vs. 29.9% (23/97); blood pressure monitoring: 83.3% (80/96) vs. 56.7% (55/97); weight monitoring:78.1% (75/96) vs. 13.4% (13/97)] were all significantly higher in the management group than in control group. For patients with New York Heart Function III-IV, the score of the LiHFe questionnaire (43.7 ± 9.2 vs. 49.5 ± 11.3), the incidence of cardiovascular events [63.3% (19/30) vs. 90.3% (28/31)], the days of hospitalization [(8.2 ± 3.2)days vs. (13.9 ± 10.9) days], and the cost for hospitalization [(2873.3 ± 401.6) Yuan vs. (4525.8 ± 6417.8) Yuan] were all significantly lower in the management group (n = 30) than in the control group (n = 31) (all P < 0.05). CONCLUSIONS: The community-based management model for heart failure patients in the community level is effective to improve the management and outcome in this cohort.


Subject(s)
Community Medicine/organization & administration , Heart Failure/therapy , Hospitals, General , Chronic Disease , Heart Failure/prevention & control , Humans , Treatment Outcome
15.
ACS Macro Lett ; 1(11): 1244-1248, 2012 Nov 20.
Article in English | MEDLINE | ID: mdl-35607148

ABSTRACT

The depth-dependent structure of a poly(styrene-b-methylmethacrylate) (PS-PMMA) line grating (46 nm pitch) was calculated from quantitative analysis of small-angle X-ray scattering profiles. These data demonstrate that domain shapes are significantly deformed near the substrate interface, where the local PS domain shape resembles an hourglass. The bulk equilibrium dimension is recovered near the center of a 64 nm thick film. Simulations based on self-consistent field theory suggest that deformations near the substrate are caused by extensive penetration of the copolymer domains into the underlying substrate coating (a PS-brush). These findings suggest that new coatings for block copolymer directed self-assembly should consider copolymer penetration lengths in addition to tailoring surface energetics. Furthermore, given the resolution and ensemble-averaging features of synchrotron X-ray scattering, we argue that it has the potential to emerge as a "gold-standard" or "benchmark" dimensional metrology and library validation tool for high density, sub-10 nm features.

16.
ACS Macro Lett ; 1(11): 1347-1351, 2012 Nov 20.
Article in English | MEDLINE | ID: mdl-35607170

ABSTRACT

Polyethylene (PE) has been widely used in a myriad of consumer products and critical infrastructure products such as underground gas and water pipes. These products are often made of blends of multiple types of PE with different molecular architectures. Although the long-term performance of these products is largely dictated by their local molecular structure, it has been studied mostly by indirect and bulk-averaging methods such as calorimetry and neutron scattering due to lack of chemical contrast for conventional imaging techniques. We demonstrate that broadband coherent anti-Stokes Raman scattering (CARS) microscopy can acquire images of the chemical composition and molecular orientation of a miscible semicrystalline PE blend with two different molecular architectures. We discuss the detailed crystal structure observed at different length scales and new insights it provides into polymer crystal morphology.

17.
Dent Mater ; 27(10): 972-82, 2011 Oct.
Article in English | MEDLINE | ID: mdl-21774976

ABSTRACT

OBJECTIVE: The objective of this study is to improve the performance of dental resins by adding a small amount of titanium dioxide nanoparticles (TiO2 NPs), which have outstanding mechanical properties and unique photoactivities. METHODS: Acrylic acid modified TiO2 NPs (AP25) were prepared and added to a mixture of bis-phenol-A-dimethacrylate and triethylene glycol dimethacrylate (mass ratio 1:1) at seven mass fractions. Disks made of these resins were subjected to FTIR microspectroscopy, nanoindentation, microindentation, and 3-point bending to determine the degree of vinyl conversion (DC) modulus and hardness. The shear bond strengths (SBS) of dentin adhesives containing various amount of AP25 were also examined. RESULTS: The DC increased as a function of mass fraction of AP25 and reached a plateau at 0.1%. The DC of the resin mixture was improved by ≈7% up to 91.7 ± 0.8%. The elastic modulus and hardness of the composites increased initially as more AP25 were added, and decreased after reached the maximum value at approximately 0.06% mass fraction of AP25. The maximum elastic modulus was ≈48% higher than that of the NP-free resin, and the maximum hardness was more than twice higher than that of the NP-free resin. Using these resin composites as dental adhesives, the mean SBS using resins with 0.1% mass fraction of AP25 was ≈30% higher than those using NP-free resin. SIGNIFICANCE: By adding a small amount of AP25 to the resin, the DC and the mechanical properties of resins were improved dramatically. These findings could lead to better performing dental adhesives.


Subject(s)
Resin Cements/chemistry , Titanium , Acrylates/chemistry , Bisphenol A-Glycidyl Methacrylate/chemistry , Dental Stress Analysis , Elastic Modulus , Hardness , Light-Curing of Dental Adhesives , Materials Testing , Nanoparticles , Pliability , Polyethylene Glycols/chemistry , Polymethacrylic Acids/chemistry , Shear Strength , Spectroscopy, Fourier Transform Infrared
18.
Adv Mater ; 23(3): 388-408, 2011 Jan 18.
Article in English | MEDLINE | ID: mdl-20848595

ABSTRACT

Photoresist materials enable the fabrication of advanced integrated circuits with ever-decreasing feature sizes. As next-generation light sources are developed, using extreme ultraviolet light of wavelength 13.5 nm, these highly tuned formulations must meet strict image-fidelity criteria to maintain the expected performance gains from decreases in feature size. However, polymer photoresists appear to be reaching resolution limits and advancements in measurements of the in situ formed solid/solid and solid/liquid interface is necessary. This Review focuses on the chemical and physical structure of chemically amplified photoresists at the lithographic feature edge at length scales between 1 nm and 100 nm. Neutron reflectivity measurements provide insight into the nanometer-scale composition profiling of the chemical latent image at an ideal lithographic line-edge that separates optical resolution effects from materials processing effects. Four generations of advanced photoresist formulations were examined over the course of seven years to quantify photoresist/photoacid and photoresist/developer interactions on the fidelity of lithographic features. The outcome of these measurements complement traditional resist design criteria by providing the effects of the impacts of the photoresist and processing on the feature fidelity. These physical relations are also described in the context of novel resist architectures under consideration for next-generation photolithography with extreme-ultraviolet radiation.


Subject(s)
Neutron Diffraction , Polymers/chemistry , Amines/chemistry , Diffusion , Photolysis
19.
J Phys Condens Matter ; 22(47): 474001, 2010 Dec 01.
Article in English | MEDLINE | ID: mdl-21386608

ABSTRACT

Off-specular neutron reflectometry was applied to characterize the form and amplitude of lateral compositional variations at a buried reaction-diffusion front. In this work, off-specular neutron measurements were first calibrated using off-specular x-ray reflectivity and atomic force microscopy via a roughened glass surface, both as a free surface and as a buried interface that was prepared by spin coating thin polymer films upon the glass surface. All three methods provided consistent roughness values despite the difference in their detection mechanism. Our neutron results demonstrated, for the first time, that the compositional heterogeneity at a buried reaction front can be measured; the model system used in this study mimics the deprotection reaction that occurs during the photolithographic process necessary for manufacturing integrated circuits.


Subject(s)
Algorithms , Materials Testing/methods , Neutron Diffraction/methods , Polymers/chemistry , X-Ray Diffraction/methods
20.
Langmuir ; 25(18): 10886-92, 2009 Sep 15.
Article in English | MEDLINE | ID: mdl-19630407

ABSTRACT

Peptides have been shown to mediate the reduction and clustering of inorganic ions during biomineralization processes to build nanomaterials with well-defined shape, size, and composition. This precise control has been linked to specific amino acid sequence; however, there is a lack of information about the role of peptides during mineralization. Here, we investigate the nucleation and growth behavior of Au nanocrystals that are mediated by the engineered peptide AYSSGAPPMPPF. Unlike other nanocrystal synthesis schemes, this peptide produces Au nanocrystals from Au(III) ions at very low relative peptide concentrations, at ambient temperature, and in water at neutral pH. Our data show that (i) the peptide AYSSGAPPMPPF actually inhibits nucleation and growth of nanocrystals, (ii) HEPES plays an active chemical role as the reducing agent, and (iii) HAuCl4 accelerates the kinetics of nanoparticle nucleation and growth. Herein, we propose empirical rate laws for nucleation and growth of Au nanocrystals and compare kinetic rate laws for this peptide, citrate, and various other polymer ligands. We find that the peptide belongs to a unique class of nonreducing inhibitor ligands regulating the surface-reaction-limited growth of nanocrystals.


Subject(s)
Bacteriophages/chemistry , Gold/chemistry , Metal Nanoparticles/chemistry , Peptides/chemistry , Amino Acid Sequence , Buffers , Chlorides/chemistry , Citric Acid/chemistry , Gold Compounds/chemistry , HEPES , Hydrogen-Ion Concentration , Kinetics , Peptides/isolation & purification , Temperature
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