Publications

Spontaneous generation of complex order in apparently simple systems is both arresting and potentially useful1,2,3,4,5,6,7,8,9,10,11. Here we describe the appearance of complex, ordered structures induced by the buckling of thin metal films owing to thermal contraction of an underlying substrate. We deposit the films from the vapour phase on a thermally expanded polymer (polydimethylsiloxane, PDMS). Subsequent cooling of the polymer creates compressive stress in the metal film that is relieved by buckling with a uniform wavelength of 20–50 micrometres. The waves can be controlled and orientated by relief structures in the surface of the polymer, which can set up intricate, ordered patterns over large areas. We can account qualitatively for the size and form of the patterned features in terms of the non-uniform stresses developed in the film near steps on the polymer substrate. This patterning process may find applications in optical devices such as diffraction gratings and optical sensors, and as the basis for methods of strain analysis in materials.

We report the nanocluster-catalyzed growth of ultralong and highly uniform single-crystalline silicon nanowires (SiNWs) with millimeter-scale lengths and aspect ratios up to approximately 100 000. The average SiNW growth rate using disilane (Si2H6) at 400 °C was 31 μm/min, while the growth rate determined for silane (SiH4) reactant under similar growth conditions was 130 times lower. Transmission electron microscopy studies of millimeter-long SiNWs with diameters of 20−80 nm show that the nanowires grow preferentially along the ⟨110⟩ direction independent of diameter. In addition, ultralong SiNWs were used as building blocks to fabricate one-dimensional arrays of field-effect transistors (FETs) consisting of approximately 100 independent devices per nanowire. Significantly, electrical transport measurements demonstrated that the millimeter-long SiNWs had uniform electrical properties along the entire length of wires, and each device can behave as a reliable FET with an on-state current, threshold voltage, and transconductance values (average ±1 standard deviation) of 1.8 ± 0.3 μA, 6.0 ± 1.1 V, 210 ± 60 nS, respectively. Electronically uniform millimeter-long SiNWs were also functionalized with monoclonal antibody receptors and used to demonstrate multiplexed detection of cancer marker proteins with a single nanowire. The synthesis of structurally and electronically uniform ultralong SiNWs may open up new opportunities for integrated nanoelectronics and could serve as unique building blocks linking integrated structures from the nanometer through millimeter length scales.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTUnusual Photoluminescence Behavior of C70S. M. Argentine, A. H. Francis, C.-C. Chen, C. M. Lieber, and J. S. SiegelCite this: J. Phys. Chem. 1994, 98, 30, 7350–7354Publication Date (Print):July 1, 1994Publication History Published online1 May 2002Published inissue 1 July 1994https://pubs.acs.org/doi/10.1021/j100081a019https://doi.org/10.1021/j100081a019research-articleACS PublicationsRequest reuse permissionsArticle Views234Altmetric-Citations29LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access options Get e-Alerts

Several studies have demonstrated age-related changes in vertebral dimensions. Vertebral size has been reported to increase among elderly adults, with periosteal apposition resulting in increased cross-sectional area (CSA) of the vertebral corpus combined with reduction in bone mineral density. These changes in CSA are observed to be sex-specific, as the pronounced increase of vertebral CSA is found only in elderly males. However, the reduction in bone mineral density in old age is apparent within both sexes. It is thus hypothesized that higher fracture risk in elderly women is a result of their incapacity to increase vertebral size and thus adapt to bone mineral reduction. In this study, our aim was to explore whether the onset of these changes could be ascribed to specific age intervals and whether the proposed differences between the sexes are as great as previously suggested. To conduct this study we utilized two large early 20th century skeletal collections known as Terry and Bass (n = 181). We also utilized data from two lumbar spine magnetic resonance imaging samples as a modern-day reference (n = 497). Age, sex and ethnicity of all individuals were known. Vertebral CSA was determined by measuring three width and length dimensions from the corpus of the fourth lumbar vertebra (L4). Our results indicate only a moderate association between age and vertebral CSA. This association was observed to be relatively similar in both sexes, and we thus conclude that there is no clear sex-specific compensatory mechanism for age-related bone loss in vertebral size.

Although information is ubiquitous, and its technology arguably among the highest that humankind has produced, its very ubiquity has posed new types of problems. Three that involve storage of information (rather than computation) include its usage of energy, the robustness of stored information over long times, and its ability to resist corruption through tampering. The difficulty in solving these problems using present methods has stimulated interest in the possibilities available through fundamentally different strategies, including storage of information in molecules. Here we show that storage of information in mixtures of readily available, stable, low-molecular-weight molecules offers new approaches to this problem. This procedure uses a common, small set of molecules (here, 32 oligopeptides) to write binary information. It minimizes the time and difficulty of synthesis of new molecules. It also circumvents the challenges of encoding and reading messages in linear macromolecules. We have encoded, written, stored, and read a total of approximately 400 kilobits (both text and images), coded as mixtures of molecules, with greater than 99% recovery of information, written at an average rate of 8 bits/s, and read at a rate of 20 bits/s. This demonstration indicates that organic and analytical chemistry offer many new strategies and capabilities to problems in long-term, zero-energy, robust information storage.

Background: Plant-based diets are recommended to lower the risk of type 2 diabetes (T2D) and coronary heart disease (CHD). Proteomic responses to plant-based diets may reveal biological pathways underlying the associations between plant-based diets and cardiometabolic disease risk. Hypothesis: Proteomic profiles reflecting adherence and biological response to an overall plant-based diet index (PDI) and a healthy PDI (hPDI) will associate with lower risks of T2D and CHD, but to an unhealthy PDI (uPDI) will associate with higher risks. Methods: We analyzed baseline plasma Olink antibody-based proteomic profiling and food frequency questionnaire (FFQ) data from 1,660 participants in the Nurses’ Health Study (NHS), NHSII, and Health Professional Follow-up Study. First, proteome-wide association analyses were conducted among 532 proteins for each PDI, adjusting for demographics, lifestyle, and BMI. For proteins with p <0.05, we applied elastic net regression with 10-fold cross-validation to develop plasma proteomic profiles related to baseline self-reported PDIs in a training set (n=1,162). We validated these profiles in a testing set (n=498). Multivariable Cox regression models examined associations between proteomic profiles of PDIs and incident T2D and CHD, adjusting for respective FFQ-derived PDI scores and many potential confounders. Results: We documented 173 T2D cases and 85 CHD cases during median follow-up periods of 23 and 24 years. We identified proteomic profiles comprised of 35, 54, and 40 proteins that correlated with (Spearman r) the FFQ-derived PDI (0.23), hPDI (0.29), and uPDI (0.23) scores, respectively. Each SD increment in the proteomic profiles of the PDI and hPDI was associated with a lower incident T2D risk (PDI: HR=0.59 [0.50, 0.69]; hPDI: HR=0.75 [0.64, 0.88]), whereas the proteomic profile of the uPDI was associated with a higher incident T2D risk (HR=1.37 [1.17, 1.60]). Each SD increment in the PDI proteomic profile, but not the hPDI proteomic profile, was associated with a lower incident CHD risk (HR=0.76 [0.60, 0.96]), whereas the uPDI proteomic profile was associated with a higher incident CHD risk (HR=1.28 [1.02, 1.60]). All the associations remained statistically significant after further adjustment for BMI, except for the association between the hPDI proteomic profile and T2D risk (HR=0.87 [0.73, 1.03]). Conclusions: Proteomic profiles of PDIs were associated with risks of T2D and CHD, independent of self-reported diet measures.

Although soft devices (grippers, actuators, and elementary robots) are rapidly becoming an integral part of the broad field of robotics, autonomy for completely soft devices has only begun to be developed. Adaptation of conventional systems of control to soft devices requires hard valves and electronic controls. This paper describes completely soft pneumatic digital logic gates having a physical scale appropriate for use with current (macroscopic) soft actuators. Each digital logic gate utilizes a single bistable valve-the pneumatic equivalent of a Schmitt trigger-which relies on the snap-through instability of a hemispherical membrane to kink internal tubes and operates with binary high/low input and output pressures. Soft, pneumatic NOT, AND, and OR digital logic gates-which generate known pneumatic outputs as a function of one, or multiple, pneumatic inputs-allow fabrication of digital logic circuits for a set-reset latch, two-bit shift register, leading-edge detector, digital-to-analog converter (DAC), and toggle switch. The DAC and toggle switch, in turn, can control and power a soft actuator (demonstrated using a pneu-net gripper). These macroscale soft digital logic gates are scalable to high volumes of airflow, do not consume power at steady state, and can be reconfigured to achieve multiple functionalities from a single design (including configurations that receive inputs from the environment and from human users). This work represents a step toward a strategy to develop autonomous control-one not involving an electronic interface or hard components-for soft devices.