Membrane transfer process for the creation of low-noise solid state nanopore devices

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 81-83).Nanopore sensors are an emerging technology whereby the modulation of a current trace upon passage of the analyte through the nanopore is used to infer the properties of the analyte. This technology is particularly attractive because it is label-free, rapid, and intrinsically single molecule. However, the ability to infer molecular properties with nanometer precision, either in size or sequencing, is obscured by noise in the measurement. The precision of this inference can be significantly improved by reducing noise and by performing multiple measurements on the same molecule. Solid state nanopores, made in free standing membranes, however, have traditionally exhibited high levels of capacitive noise at 100 kHz bandwidths, as well as poor confinement of the electric field around the nanopore. In this thesis, a novel device concept is designed for creating solid state nanopores whereby the free standing membrane is transferred over a PDMS microchannel. By eliminating the silicon wafer backing, capacitive noise is dramatically reduced. Furthermore, the microchannel confines the electric field outside the nanopore, thereby enhancing the ability to perform multiple measurements.by Tarun Jain.S.M

Primordial features due to a step in the inflaton potential

Certain oscillatory features in the primordial scalar power spectrum are known to provide a better fit to the outliers in the cosmic microwave background data near the multipole moments of $\ell=22$ and 40. These features are usually generated by introducing a step in the popular, quadratic potential describing the canonical scalar field. Such a model will be ruled out, if the tensors remain undetected at a level corresponding to a tensor-to-scalar ratio of, say, $r\simeq 0.1$. In this work, in addition to the popular quadratic potential, we investigate the effects of the step in a small field model and a tachyon model. With possible applications to future datasets (such as PLANCK) in mind, we evaluate the tensor power spectrum exactly, and include its contribution in our analysis. We compare the models with the WMAP (five as well as seven-year), the QUaD and the ACBAR data. As expected, a step at a particular location and of a suitable magnitude and width is found to improve the fit to the outliers (near $\ell=22$ and 40) in all these cases. We point out that, if the tensors prove to be small (say, $r\lesssim 0.01$), the quadratic potential and the tachyon model will cease to be viable, and more attention will need to be paid to examples such as the small field models.Comment: 17 pages, 6 figures, Discussion shortened, Version to appear in JCA

Invesitigation of Malware and Forensic Tools on Internet

Malware is an application that is harmful to your forensic information. Basically, malware analyses is the process of analysing the behaviours of malicious code and then create signatures to detect and defend against it.Malware, such as Trojan horse, Worms and Spyware severely threatens the forensic security. This research observed that although malware and its variants may vary a lot from content signatures, they share some behaviour features at a higher level which are more precise in revealing the real intent of malware. This paper investigates the various techniques of malware behaviour extraction and analysis. In addition, we discuss the implications of malware analysis tools for malware detection based on various techniques

Multiple hepatic lesions in a case of isolated hepatic tuberculosis simulating metastases on 18F-FDG PET/CT imaging

Hepatic tuberculosis is an unusual form of extrapulmonary tuberculosis and constitutes less than 1% of all cases of tuberculosis. Imaging studies for hepatic tuberculosis are nonspecific and mimic primary or metastatic carcinoma. Here we present 18F-FDG PET/CT images of a 25-year-old male patient with isolated hepatic tuberculosis

The tensor-to-scalar ratio in punctuated inflation

Recently, we have shown that scalar spectra with lower power on large scales and certain other features naturally occur in {\it punctuated inflation}, i.e. the scenario wherein a brief period of rapid roll is sandwiched between two stages of slow roll inflation. Such spectra gain importance due to the fact that they can lead to a better fit of the observed Cosmic Microwave Background (CMB) anisotropies, when compared to the conventional, featureless, power law spectrum. In this paper, with examples from the canonical scalar field as well as the tachyonic models, we illustrate that, in punctuated inflation, a drop in the scalar power on large scales is {\it always} accompanied by a rise in the tensor power and, hence, an even more pronounced increase in the tensor-to-scalar ratio $r$ on these scales. Interestingly, we find that $r$ actually {\it exceeds well beyond unity} over a small range of scales. {\it To our knowledge, this work presents for the first time, examples of single scalar field inflationary models wherein $r\gg 1$.} This feature opens up interesting possibilities. For instance, we show that the rise in $r$ on large scales translates to a rapid increase in the angular power spectrum, $C_{\ell}^{\rm BB}$, of the B-mode polarization of the CMB at the low multipoles. We discuss the observational implications of these results.Comment: v1: 16 pages, 6 figures; v2: RevTeX, 12 pages, 6 figures, minor changes, to appear in Physical Review

Effectiveness of Science Newspaper ‘Vaigyaniik Drishtikon’ in Science Communication: A Case Study

Every citizen in society should have the opportunity to think, understand and work scientifically. Under the Fundamental Duties as per Article 51A (H) in the Constitution of India, it has been said that it will be the duty of every citizen of India to develop a scientific temper, humanism and a spirit of inquiry and reform. Research always tends to find the new things, revolving around the facts and data. This research is towards the effectiveness and role of science newspaper Vaigyanik Drishtikon in science communication in Jaipur. The role of this research is to understand, analyse and check the effectiveness of the newspaper. Vaigyanik Drishtikon a fortnightly science newspaper is running from last 22 years and regarded as the first science newspaper in India. So it is playing a wide and vivid role in developing scientific temperament and awareness in the society. In life, we always need a way to reach aim, simultaneously in research there is a need of methodology. For conveying the best research and finding the outcomes researcher choose the online survey method. 21st century is the age of technology. Google form is quite handy tool for collecting data. Researcher have used Google form to collect 425 responses of a questionnaire comprising 22 questions. Most of the people participating in the survey have fully accepted that 'Vaigyanik Drishtikon' has developed their scientific understanding to a great extent and made them aware of the logical, informative and interesting knowledge of science in simple language. This kind of work need to be accomplish and many more to do

Enhanced discrimination of DNA molecules in nanofluidic channels through multiple measurements

Author Manuscript 2013 March 21.Nanofluidic sensing elements have been the focus of recent experiments for numerous applications ranging from nucleic acid fragment sizing to single-molecule DNA sequencing. These applications critically rely on high measurement fidelity, and methods to increase resolution are required. Herein, we describe fabrication and testing of a nanochannel device that enhances measurement resolution by performing multiple measurements (>100) on single DNA molecules. The enhanced measurement resolution enabled length discrimination between a mixture of λ-DNA (48.5 kbp) and T7 DNA (39.9 kbp) molecules, which were detected as transient current changes during translocation of the molecules through the nanochannel. As long DNA molecules are difficult to resolve quickly and with high fidelity with conventional electrophoresis, this approach may yield potentially portable, direct electrical sizing of DNA fragments with high sensitivity and resolution.National Institutes of Health (U.S.) (Grant R21EB009180)United States. Air Force (Contract FA8721-05-C- 0002

Unusual metastatic sex cord stromal tumor - staging and response assessment

Metastatic sex cord stromal tumor (SCST) is rare and contributing <1% of ovarian tumors. A 42-year-old female presented with lower abdominal pain for 2 months. Ultrasonography revealed masses in the abdominal and pelvic. USG guided biopsy from the pelvic mass revealed SCST. For staging, whole body F-18 fluorodeoxyglucose positron emission tomography-computed tomography was performed and revealed heterogenous mildly FDG avid retroperitoneal and bilateral pelvic masses with lung nodules. To confirm the nature of the lung nodule; PET-CT guided biopsy performed and revealed metastatic SCST. After three cycle of chemotherapy, clinical, biochemical and imaging show partial response to treatment

Imaging resemblance but diagnostic disparity in cervix cancer: a rare case report

F-18 FDG PET-CT is an establish modality for staging of cervical cancer. The high uptake value in PET with no evidence of necrosis in CECT is generally understood malignant pathology in known cancer patients. A 47 year-old-female with cervix carcinoma underwent staging FDG PET-CT. It showed FDG avid primary lesion in cervix with FDG avid pelvic, retroperitoneal, mediastinal and supraclavicular lymph nodes. USG guided FNA from the supraclavicular lymph node revealed tuberculosis. Now patient scheduled for ATT and chemotherapy

CMB Polarization and Temperature Power Spectra Estimation using Linear Combination of WMAP 5-year Maps

We estimate CMB polarization and temperature power spectra using WMAP 5-year foreground contaminated maps. The power spectrum is estimated by using a model independent method, which does not utilize directly the diffuse foreground templates nor the detector noise model. The method essentially consists of two steps, (i) removal of diffuse foregrounds contamination by making linear combination of individual maps in harmonic space and (ii) cross-correlation of foreground cleaned maps to minimize detector noise bias. For temperature power spectrum we also estimate and subtract residual unresolved point source contamination in the cross-power spectrum using the point source model provided by the WMAP science team. Our $TT$, $TE$ and $EE$ power spectra are in good agreement with the published results of the WMAP science team. The error bars on the polarization power spectra, however, turn out to be smaller in comparison to what is obtained by the WMAP science team. We perform detailed numerical simulations to test for bias in our procedure. We find that the bias is small in all cases. A negative bias at low $l$ in $TT$ power spectrum has been pointed in an earlier publication. We find that the bias corrected quadrupole power ($l(l+1)C_l/2\pi)$ is 532 $\mu K^2$, approximately 2.5 times the estimate (213.4 $\mu K^2$) made by the WMAP team.Comment: 28 pages 13 figure