Publications by authors named "Junlan Wang"

18 Publications

  • Page 1 of 1

Microstructure, mechanical properties and elemental composition of the terrestrial isopod Armadillidium vulgare cuticle.

J Mech Behav Biomed Mater 2022 Aug 30;132:105299. Epub 2022 May 30.

Department of Mechanical Engineering, University of Washington, Seattle, WA, 98195, USA; Department of Materials Science and Engineering, University of Washington, Seattle, WA, 98195, USA. Electronic address:

The exoskeletons of crustaceans are essential for providing protection from predators and other environmental threats. Understanding the structure and mechanical behavior of their natural armor could inspire the design of lightweight and high toughness synthetic materials. Most published work has focused on marine crustacea rather than their terrestrial counterparts, which are exposed to a multitude of unique threats. The interest in the terrestrial isopod Armadillidium vulgare (A. vulgare) has grown but the interrelationship between the microstructure, chemical composition, and mechanical properties has not been thoroughly investigated. Thus, this study aims to elucidate missing details concerning this biological mineralized composite. Exoskeleton specimens were fixated to preserve the intrinsic protein structure. We utilize scanning electron microscopy for microstructure analysis, Raman spectroscopy for elemental analysis, and nanoindentation property mapping to achieve mechanical characterization. The naturally fractured A. vulgare exoskeleton cross-section reveals four subregions with the repeating helicoidal 'Bouligand' arrangement most prominent in the endocuticle. The hardness and reduced modulus distributions exhibit a through-thickness exponential gradient with decreasing magnitudes from the outermost to the innermost layers of the exoskeleton. The Raman spectra show a graded spatial distribution of key constituents such as calcium carbonate across the thickness, some of which are consistent with the mechanical property gradient. Potential microstructure, elemental composition, and mechanical property relationships are discussed to explain how the hierarchical structure of this nanolaminate armor protects this species.
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http://dx.doi.org/10.1016/j.jmbbm.2022.105299DOI Listing
August 2022

Nanocrystal Ordering Enhances Thermal Transport and Mechanics in Single-Domain Colloidal Nanocrystal Superlattices.

Nano Lett 2022 06 31;22(12):4669-4676. Epub 2022 May 31.

School for Engineering of Matter, Transport & Energy, Arizona State University, Tempe, Arizona 85287, United States.

Colloidal nanocrystal (NC) assemblies are promising for optoelectronic, photovoltaic, and thermoelectric applications. However, using these materials can be challenging in actual devices because they have a limited range of thermal conductivity and elastic modulus, which results in heat dissipation and mechanical robustness challenges. Here, we report thermal transport and mechanical measurements on single-domain colloidal PbS nanocrystal superlattices (NCSLs) that have long-range order as well as measurements on nanocrystal films (NCFs) that are comparatively disordered. Over an NC diameter range of 3.0-6.1 nm, we observe that NCSLs have thermal conductivities and Young's moduli that are up to ∼3 times higher than those of the corresponding NCFs. We also find that these properties are more sensitive to NC diameter in NCSLs relative to NCFs. Our measurements and computational modeling indicate that stronger ligand-ligand interactions due to enhanced ligand interdigitation and alignment in NCSLs account for the improved thermal transport and mechanical properties.
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http://dx.doi.org/10.1021/acs.nanolett.2c00544DOI Listing
June 2022

Family Care, Economic Stress, and Depressive Symptoms Among Chinese Adults During the COVID-19 Outbreak: Difference by Urban and Rural Areas.

Front Psychiatry 2021 21;12:700493. Epub 2021 Jul 21.

Department of Health Policy and Management, School of Public Health, Peking University, Beijing, China.

Although several studies have shown an association of family care with a high level of depressive symptoms, the relationship between them remains indistinguishable. This study aims to examine the associations between family care, economic stress, and depressive symptoms among Chinese adults in urban and rural areas during the COVID-19 outbreak. Based on cross-sectional data collected through online surveys from February 1st to 10th 2020 in China the present study recruited 2,858 adults. It used multiple linear regression to examine the association between family care and depressive symptoms, while economic stress was examined as moderators on the above relationship. The results showed that caring for both the elderly and children was significantly associated with higher depressive symptoms compared with non-caregivers ( = 2.584, 95%CI: 1.254, 3.915), and a similar result was also found in urban areas. Also, caring for the elderly only was also had a higher level of depressive symptoms than non-caregivers in rural areas ( = 3.135, 95%CI: 0.745, 5.525). Meeting the care needs was significantly associated with lower depressive symptoms compared with unmet care needs, while for rural caregivers, the results were not significant. Besides, economic stress strengthened the effect of family care needs on depressive symptoms for sandwich-generation caregivers who provide care to both the elderly and children ( = 0.605, 95%CI: 0.077, 1.134). While in rural areas, the moderation effects of economic stress were only found for elderly caregivers ( = 1.106, 95%CI: 0.178, 2.035). These findings suggest that we should pay more attention to the family caregiver's mental health during the COVID-19 outbreak. In addition, more effective policies should be developed to provide financial support for family caregivers, especially for sandwich-generation caregivers and rural elderly caregivers.
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http://dx.doi.org/10.3389/fpsyt.2021.700493DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8335154PMC
July 2021

Evolution of the Laser-Induced Spallation Technique in Film Adhesion Measurement.

Appl Mech Rev 2021 May 28;73(3):030802. Epub 2021 Apr 28.

Department of Mechanical Engineering, University of Kentucky, Lexington, KY 40506.

Laser-induced spallation is a process in which a stress wave generated from a rapid, high-energy laser pulse initiates the ejection of surface material opposite the surface of laser impingement. Through knowledge of the stress-wave amplitude that causes film separation, the adhesion and interfacial properties of a film-on-substrate system are determined. Some advantages of the laser spallation technique are the noncontact loading, development of large stresses (on the order of GPa), and high strain rates, up to 10/s. The applicability to both relatively thick films, tens of microns, and thin films, tens of nm, make it a unique technique for a wide range of materials and applications. This review combines the available knowledge and experience in laser spallation, as a state-of-the-art measurement tool, in a comprehensive pedagogical publication for the first time. An historical review of adhesion measurement by the laser-induced spallation technique, from its inception in the 1970s through the present day, is provided. An overview of the technique together with the physics governing the laser-induced spallation process, including functions of the absorbing and confining materials, are also discussed. Special attention is given to applications of laser spallation as an adhesion quantification technique in metals, polymers, composites, ceramics, and biological films. A compendium of available experimental parameters is provided that summarizes key laser spallation experiments across these thin-film materials. This review concludes with a future outlook for the laser spallation technique, which approaches its semicentennial anniversary.
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http://dx.doi.org/10.1115/1.4050700DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8208493PMC
May 2021

The functional landscape of Golgi membrane protein 1 (GOLM1) phosphoproteome reveal GOLM1 regulating P53 that promotes malignancy.

Cell Death Discov 2021 Mar 1;7(1):42. Epub 2021 Mar 1.

Laboratory of Allergy and Precision Medicine, Chengdu Institute of Respiratory Health, The Third People's Hospital of Chengdu, Chengdu, Sichuan, China.

Golgi membrane protein 1 (GOLM1) was implicated in carcinogenesis of multiple types of cancer. However, Phosphoproteome landscapes of GOLM1 overexpression in lung cancer remain largely unknown. In this study, using data from the Cancer Genome Atlas (TCGA) and phosphoproteome, we systematically evaluated the feature of GOLM1 and studied its prognostic value in non-small cell lung cancer (NSCLC). The proliferation, migration, and invasion capacities in PC9 cell with GOLM1 overexpression were determined using Trans-well system assay. Tumor engrafts was visualized in mice models and confirmed by ex vivo. An increased expression of GOLM1 had shorter overall survival (OS) in patients with NSCLC in TCGA database. GOLM1 in single gene set enrichment analysis (GSEA) related to adherent's junction, cell cycle, and pathway in cancer. Overexpression of GOLM1 in GOLM1OE PC9 cells promoted cell proliferation, migration, and invasion. Decreased migration and invasion potential were also observed in knockdown of GOLM1 in GOLM1KD PC9 cells in migration assay. An increased expression of GOLM1 could significantly increase the growth of tumor in xenograft mice models. phosphoproteome analysis showed 239 upregulated and 331 downregulated Phosphorylated proteins in GOLM1OE PC9 cells. Overexpression of GOLM1 in GSEA was significantly related to P53 in MAPK signaling pathway. Overexpression of GOLM1enhanced the phosphorylation of P53 protein at site S315 but inhibited the formation of P53 tetramers. These results indicate that overexpression GOLM1 enhances non-small-cell carcinoma aggressiveness through inhibited the formation of P53 tetramer.
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http://dx.doi.org/10.1038/s41420-021-00422-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7921442PMC
March 2021

Effect of MTGase on silver carp myofibrillar protein gelation behavior after peroxidation induced by peroxyl radicals.

Food Chem 2021 Jul 11;349:129066. Epub 2021 Jan 11.

College of Food Science and Engineering, Northwest A&F University, No. 22 Xinong Road, Yangling, Shaanxi 712100, China. Electronic address:

The objective of this study was to explore the oxidative modification induced by AAPH (2,2'-azobis (2-amidinopropane) dihydrochloride) on the microbial transglutaminase (MTGase) cross-linking reaction and gelling properties of silver carp myofibril protein (SCMP). Compared to AAPH treatment, MTGase addition resulted further changes of protein properties as evidenced by the decreasing free amino and thiol group content, the decreased secondary and tertiary structure, and the increasing storage modulus (G') and gel strength (P < 0.05). The proper oxidation induced by AAPH (5 mM) promoted the glutamine-lysine and disulfide cross-linking due to MTGase (10 U/g). Therefore, the quality of the SCMP gel was improved with a good water-holding capacity (WHC), gel strength and G'. This results could lay a theoretical foundation for the development of silver carp surimi products with good quality. Chemical compounds: (2,2'-azobis(2-amidinopropane)dihydrochloride (PubChem CID:76344); O-Phthalaldehyde (PubChem CID:4807); 5,5'-Dithiobis(2-Nitrobenzoic Acid) (PubChem CID:6254); 8-Anilino-1-naphthalenesulfonic acid (PubChem CID:1369); Acrylamide (PubChem CID: 6579); β-Mercaptoethanol (PubChem CID: 1567); Sodium dodecyl sulfate (PubChem CID:3423265).
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http://dx.doi.org/10.1016/j.foodchem.2021.129066DOI Listing
July 2021

Oral-maxillofacial adverse events related to antimalarials.

Oral Dis 2021 Sep 24;27(6):1376-1382. Epub 2020 Jun 24.

Department of Stomatology, Jinling Hospital, Medical School of Nanjing University, Nanjing, China.

Malaria is a worldwide parasitic disease, which affects millions of lives every year. Various medications are recommended by WHO for prevention and treatment of malaria. However, adverse events caused by antimalarials were frequently reported, some of which were severe and fatal. Disorders of many organs related to antimalarials have been well recognized, whereas few studies concentrated on the relationship between antimalarials and oral-maxillofacial system health. Current review generalized the relevance of antimalarials to the health of oral-maxillofacial part and raised an urgent need to form a standard management for antimalarial-related oral-maxillofacial adverse events.
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http://dx.doi.org/10.1111/odi.13457DOI Listing
September 2021

MiR-133 Targets YES1 and Inhibits the Growth of Triple-Negative Breast Cancer Cells.

Technol Cancer Res Treat 2020 Jan-Dec;19:1533033820927011

Department of Breast Surgery, Shanxi Provincial Cancer Hospital, Shanxi Medical University, Taiyuan, Shanxi, China.

Triple-negative breast cancer shows worse outcome compared with other subtypes of breast cancer. The discovery of dysregulated microRNAs and their roles in the progression of triple-negative breast cancer provide novel strategies for the treatment of patients with triple-negative breast cancer. In this study, we identified the significant reduction of miR-133 in triple-negative breast cancer tissues and cell lines. Ectopic overexpression of miR-133 suppressed the proliferation, colony formation, and upregulated the apoptosis of triple-negative breast cancer cells. Mechanism study revealed that the YES Proto-Oncogene 1 was a target of miR-133. miR-133 bound the 3'-untranslated region of YES Proto-Oncogene 1 and decreased the level of YES Proto-Oncogene 1 in triple-negative breast cancer cells. Consistent with miR-133 downregulation, YES1 was significantly increased in triple-negative breast cancer, which was inversely correlated with the level of miR-133. Restoration of YES Proto-Oncogene 1 attenuated the inhibitory effects of miR-133 on the proliferation and colony formation of triple-negative breast cancer cells. Consistent with the decreased expression of YES Proto-Oncogene 1, overexpression of miR-133 suppressed the phosphorylation of YAP1 in triple-negative breast cancer cells. Our results provided novel evidence for the role of miR-133/YES1 axis in the development of triple-negative breast cancer, which indicated miR-133 might be a potential therapeutic strategy for triple-negative breast cancer.
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http://dx.doi.org/10.1177/1533033820927011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7278099PMC
January 2021

Bronchoscopic lung volume reduction procedures for emphysema: A network meta-analysis.

Medicine (Baltimore) 2020 Jan;99(5):e18936

Department of Respiratory Medicine, Chengdu Institute of Respiratory Health, the Third People's Hospital of Chengdu, China.

Bronchoscopic lung volume reduction (BLVR) offers alternative novel treatments for patients with emphysema. Comprehensive evidence for comparing different BLVR remains unclear. To estimate the effects of different BLVR on patients with emphysema. PubMed, EMBASE, Cochrane Library, and Web of Science databases from January 2001 to August 2017 were searched. Randomized clinical trials evaluated effects of BLVR on patients with emphysema. The relevant information was extracted from the published reports with a predefined data extraction sheet, and the risk of bias was assessed with the Cochrane risk of bias tools. Pair-wise metaanalyses were made using the random-effects model. A random-effects network meta-analysis was applied within a Bayesian framework. The quality of evidence contributing to primary outcomes was assessed using the GRADE framework. 13 trials were deemed eligible, including 1993 participants. The quality of evidence was rated as moderate in most comparisons. Medical care (MC)was associated with the lowest adverse events compared with intrabronchial valve (IBV)(-2.5,[-4.70 to -0.29]), endobronchial valve (EBV) (-1.73, [-2.37 to -1.09]), lung volume reduction coils (LVRC) (-0.76, [-1.24 to -0.28]), emphysematous lung sealant (ELS) (-1.53, [-2.66 to -0.39]), and airway bypass(-1.57, [-3.74 to 0.61]). Adverse events in LVRC were lower compared with ELS (-0.77,[-2.00 to 0.47]). Bronchoscopic thermal vapor ablation (BTVA) showed significant improvement in FEV1 compared with MC (0.99, [0.37 to 1.62]), IBV (1.25, [0.25 to 2.25]), and LVRC (0.72, [0.03 to 1.40] ). Six  minute walking distance (6 MWD) in ELS was significantly improved compared with other four BLVR, sham control, and MC (-1.96 to 1.99). Interestingly, MC showed less improvement in FEV1 and 6MWDcompared with EBV (-0.45, [-0.69 to -0.20] and -0.39, [-0.71 to -0.07], respectively). The mortality in MC and EBV was lower compared with LVRC alone (-0.38, [-1.16 to 0.41] and -0.50, [-1.68 to 0.68], respectively). BTVA and EBV led to significant changes in St George's respiratory questionnaire (SGRQ) compared with MC alone (-0.74, [-1.43 to -0.05] and 0.44, [0.11 to 0.78], respectively). BLVR offered a clear advantage for patients with emphysema. EBV had noticeable beneficial effects on the improvement of forced expiratory volume 1, 6MWD and SGRQ, and was associated with lower mortality compared with MC in different strategies of BLVR.
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http://dx.doi.org/10.1097/MD.0000000000018936DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7004743PMC
January 2020

microRNA-448 inhibits the progression of non-small-cell lung cancer through regulating IRS2.

J Cell Biochem 2019 08 25;120(8):13453-13463. Epub 2019 Mar 25.

Department of Pathology, Affiliated Hospital of Hebei University of Engineering, Handan, Hebei, China.

Recently, microRNA-448 (miR-448) has been reported to be a tumor-associated miRNA in many human cancers. In this study, we investigated the function of miR-448 in non-small-cell lung cancer (NSCLC) progression and confirmed the relationship between miR-448 and insulin receptor substrates 2 (IRS2). First, downregulation of miR-448 and upregulation of IRS2 were detected in NSCLC using the quantitative real-time polymerase chain reaction (qRT-PCR) assay. Furthermore, the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay showed that miR-448 inhibited cell viability in NSCLC. Transwell and Western blot assays indicated that the upregulation of miR-448 inhibited cell metastasis and epithelial-to-mesenchymal transition (EMT) in NSCLC. And it was found that overexpression of miR-448 reduced the adhesion of A549 cells to HUVEC cells using the adhesion assay. Furthermore, the dual luciferase assay indicated that miR-448 directly targeted IRS2 in NSCLC. In addition, it was found that IRS2 silencing had an inhibitory effect on the progression of NSCLC, and the upregulation of IRS2 partially impaired the inhibitory effect of miR-448 in NSCLC. Briefly, overexpression of miR-448 inhibited cell proliferation, metastasis, and EMT by suppressing IRS2 expression in NSCLC.
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http://dx.doi.org/10.1002/jcb.28619DOI Listing
August 2019

Demineralized bone matrix used for direct pulp capping in rats.

PLoS One 2017 2;12(3):e0172693. Epub 2017 Mar 2.

Key Laboratory of Oral Diseases of Jiangsu Province and Stomatological School of Nanjing Medical University, Nanjing, Jiangsu, China.

Objectives: To evaluate the wound healing process following direct pulp capping with demineralized bone matrix (DBM) and calcium hydroxide (Ca(OH)2).

Methods: Fifty 8-weeks-old SPF Wistar male rats were divided into two groups: one was the DBM treated group, and the other was the Ca(OH)2 treated group. Pulpotomy was performed on the maxillary first molar of one side of each rat, and the another side was left as the blank control. Rats were sacrificed after each observation period (1, 3, 7, 14 and 28 days) and specimen slices were made. Hematoxylin-Eosin (HE) staining was used for observing the changes of pulp tissue, and immunohistochemical staining was used for observing the expression of reparative dentinogenesis-related factors runt transcription factor 2 (Runx2), type I collagen (COL I), osteocalcin (OCN) and dentin sialoprotein (DSP).

Results: Inflammatory cell infiltration (ICI) and pulp tissue disorganization (PTD) could be observed in both the DBM and Ca(OH)2 groups at all observation periods. The DBM group showed slighter ICI on 1 and 28 days and milder PTD on 28 days, with a significant difference (P<0.05). Reparative dentin formation (RDF) could initially be observed on 14 days postoperatively, and the DBM group showed more regular and thinner RDF with significant differences on 14 and 28 days compared with the Ca(OH)2 group (P<0.05). In both groups, the expression of Runx2, COL I, DSP and OCN were positive. Generally, the expression of these four factors in the DBM group was stronger than the Ca(OH)2 group on the same observation periods.

Conclusions: DBM had the ability of inducing odontoblast differentiation and promoting dentinogenesis. DBM could initiate physiologic wound healing in pulp and had the ability to promote reparative dentin formation. Consequently, DBM may be an acceptable alternative for direct pulp capping.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0172693PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5333824PMC
August 2017

Laser-Induced Spallation of Microsphere Monolayers.

Langmuir 2016 08 1;32(31):7730-4. Epub 2016 Aug 1.

Department of Mechanical Engineering, University of Washington , Seattle, Washington 98195, United States.

The detachment of a semiordered monolayer of polystyrene microspheres adhered to an aluminum-coated glass substrate is studied using a laser-induced spallation technique. The microsphere-substrate adhesion force is estimated from substrate surface displacement measurements obtained using optical interferometry, and a rigid-body model that accounts for the inertia of the microspheres. The estimated adhesion force is compared with estimates obtained using an adhesive contact model together with interferometric measurements of the out-of-plane microsphere contact resonance, and with estimated work of adhesion values for the polystyrene-aluminum interface. Scanning electron microscope images of detached monolayer regions reveal a unique morphology, namely, partially detached monolayer flakes composed of single hexagonal close packed crystalline domains. This work contributes to the fields of microsphere adhesion and contact dynamics, and demonstrates a unique monolayer delamination morphology.
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http://dx.doi.org/10.1021/acs.langmuir.6b00982DOI Listing
August 2016

Application of spatio-temporal image correlation technology in the diagnosis of fetal cardiac abnormalities.

Exp Ther Med 2013 Jun 9;5(6):1637-1642. Epub 2013 Apr 9.

Department of Ultrasound, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, P.R. China.

Congenital heart disease is the birth defect with the highest incidence in China. Its timely and accurate prenatal diagnosis is critical for appropriate perinatal and postnatal management and salvage treatment. With improvements in the diagnostic capabilities of ultrasound and clinical manipulation techniques, prenatal diagnosis is conducted increasingly early and with greater accuracy. However, the representations of tiny blood vessels and the determination of abnormal spatial structures in the fetal period continue to cause difficulties in prenatal diagnosis. In theory, spatio-temporal image correlation (STIC) technology is able to compensate for the defects of previous traditional two-dimensional (2D) ultrasound and improve the diagnostic accuracy. The aim of the present study was to investigate the clinical application value of STIC technology combined with traditional 2D ultrasound in the diagnosis of fetal cardiac abnormalities. A total of 1,286 fetuses were subjected to sequential echocardiographic examination, during which STIC technology was used to collect heart volume data and carry out image post-processing and off-line analysis. In addition, the prenatal and postnatal echocardiography results were compared with the pathology results following the induced labor of fetuses with cardiac abnormalities. The sensitivity, specificity, misdiagnosis rate and rate of missed diagnosis for the STIC technology in the diagnosis of prenatal fetal cardiac abnormalities were 97.4, 99.6, 0.4 and 2.6%, respectively. The total coincidence rate was 99.2% and the positive and negative predictive values were 97.9 and 99.4%, respectively; the statistics for the consistency check of the STIC technology in the diagnosis of fetal cardiac abnormalities are κ=0.991, P=0.000. STIC technology combined with fetal echocardiography may be used for the definite diagnosis of fetal heart malformations, with high sensitivity and specificity.
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http://dx.doi.org/10.3892/etm.2013.1060DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3702623PMC
June 2013

Insight into on-wafer crystallization of pure-silica-zeolite films through nutrient replenishment.

Langmuir 2011 Apr 1;27(7):3283-5. Epub 2011 Mar 1.

Department of Chemical and Environmental Engineering, University of California, Riverside, Riverside, California 92521, United States.

Tetraethylorthosilicate (TEOS) is added to a pure-silica-zeolite MEL nanoparticle suspension and the mixture is subsequently used for preparing spin-on low-dielectric constant (low-k) films. The films are then characterized by ellipsometric porosimetry, transmission electron microscopy (TEM), and nanoindentation. Investigation into the film microstructure indicates that the addition of TEOS significantly increases the fraction of the crystalline domains, decreases the inter-crystal mesopore size, and narrows the pore size distribution. Films with 12% TEOS loading have a mean pore size distribution centered at 3.5 nm (diameter) with a full width at half maximum (fwhm) of 0.8 nm, while those with no TEOS have a distribution at 11.1 nm and fwhm of 7.9 nm. At 12% TEOS loading, the reduced modulus and hardness are 11.0 and 1.12 GPa, respectively; without TEOS, the values are 6.4 and 0.57 GPa.
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http://dx.doi.org/10.1021/la200603zDOI Listing
April 2011

Finite element simulation of cell-substrate decohesion by laser-induced stress waves.

J Mech Behav Biomed Mater 2010 Apr 2;3(3):268-77. Epub 2009 Dec 2.

Department of Mechanical Engineering, University of Washington, Seattle, WA 98195, USA.

Fundamental to the development and application of biomedical devices is an understanding of the adhesion of cells to substrates. There are many experimental techniques and papers dedicated to the study of cell adhesion. This work aims to elucidate on the cell detachment mechanism in a recently reported cell adhesion measurement experiment by laser-induced stress wave technique. In the experiment the absorption of an Nd:YAG laser pulse generates a stress wave of nanoseconds duration that interacts with and detaches the cell adhered to a Si substrate. Due to the ultra-short timescale involved in the experiment, details of the detachment process were not readily observable. In this work, dynamic finite element method is used to simulate the cell-substrate decohesion process under the laser-induced stress wave loading. The results show that the combined effect of nanosecond stress wave pulse and the specific cell geometry results in a complex stress-strain state along the cell-substrate interface. The principal failure mechanism is large interfacial strains realized from the cell's tendency to spread and elongate on the substrate as a result of substrate acceleration. The cells behave like a soft elastic solid during the detachment process due to the large difference between their characteristic response time and the ultra-short duration of the applied stress wave. Evolution of the cell geometry from hydrophobic to hydrophilic contact results in the same detachment process.
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http://dx.doi.org/10.1016/j.jmbbm.2009.11.001DOI Listing
April 2010

On-wafer crystallization of ultralow-kappa pure silica zeolite films.

Angew Chem Int Ed Engl 2009 ;48(26):4777-80

Department of Chemical and Environmental Engineering, University of California, Riverside, CA 92521, USA.

A higher goal: An on-wafer crystallization process to prepare pure silica zeolite (PSZ) MEL-type films that is superior to the previously used hydrothermal process is reported. These striation-free MEL-type films (right, see picture) outperform the traditional spin-on films (left) in terms of the kappa value, mechanical properties, surface roughness, mesopore size, and size distribution.
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http://dx.doi.org/10.1002/anie.200900461DOI Listing
August 2009

Hydrofluoric-acid-resistant and hydrophobic pure-silica-zeolite MEL low-dielectric-constant films.

Langmuir 2009 May;25(9):5039-44

Department of Chemical and Environmental Engineering, University of California, Riverside, Riverside, California, USA.

A new technique for the silylation of pure-silica-zeolite MEL low-k films has been developed in which the spin-on films are calcined directly in trimethylchlorosilane or 1,1,1,3,3,3-hexamethyldisilazane (HMDS) in order to protect the films against corrosive wet etch chemicals and ambient moisture adsorption. In an alternative procedure, HMDS is also added to the zeolite suspension before film preparation. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, water-soak tests, and HF etch tests are performed to characterize the films. The dielectric constant is as low as 1.51, and the films resist HF attack up to 5.5 min. These properties are highly desirable by the semiconductor industry for next-generation microprocessors.
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http://dx.doi.org/10.1021/la803956wDOI Listing
May 2009

Mechanical and dielectric properties of pure-silica-zeolite low-k materials.

Angew Chem Int Ed Engl 2006 Sep;45(38):6329-32

Department of Chemical and Environmental Engineering, University of California, Riverside, CA 92521, USA.

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http://dx.doi.org/10.1002/anie.200602036DOI Listing
September 2006
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