Scanning thermal microscopy using nanofabricated probes

Novel atomic force microscope (AFM) probes with integrated thin film thermal sensors are presented. Silicon micromachining and high resolution electron beam lithography (EBL) have been used to make batch fabricated, functionalised AFM probes. The AFM tips, situated at the ends of Si3N4 cantilevers, are shaped either as truncated pyramids or sharp triangular asperites. The former gives good thermalisation of the sensor to the specimen for flat specimens whereas the latter gives improved access to highly topographic specimens. Tip radii for the different probes are 1 m and 50 nm respectively. A variety of metal structures have been deposited on the tips using EBL and lift-off to form Au/Pd thermocouples and Pd resistance thermometer/heaters. Sensor dimensions down to 35 nm have been demonstrated. In the case of the sharp triangular tips, holes were etched into parts of the cantilever in order to provide self alignment of the sensor to the tip. On the pyramidal tips it has been shown that multiple sensors can be made on a single tip with good definition and matching between sensors. A conventional AFM was constructed in order to test the micromachined thermal probes. During scans of a photothermal test specimen using improved access thermocouple probes, 80 nm period metal gratings were thermally resolved. This is equivalent to a thermal lateral resolution of 40 nm. Pyramidal tips with a resistance thermometer/heater, which were made for the microscopy and analysis of polymers, have been showed by others to produce high resolution thermal conductivity images. The probes have also been shown to be capable of locally heating a polymer specimen and thermomechanically measuring phase changes in small volumes of material. Also presented here is a study of scanning thermal microscopy of semiconductor structures using a commercial AFM. Included are scans of several specimens using both commercial andthe new micromachined probes. Subsurface images of voids buried under a SiO2 passivation layer were taken. It is shown that contrast caused by thermal conductivity differences in the specimen may be detected at a depth of over 200 nm

Appraisal of Non-commercial Passenger Rail Services in Britain

The appraisal of proposals for adding or withdrawing individual rail services is inevitably complex, because it needs to recognise interdependence both within the rail network and between transport modes, and to account for externalities affecting non-users. Since 1960, British appraisal procedures have changed greatly, as has the institutional setting, especially following privatisation. In May 1999, the government regulator took a major step forward when it adopted the use of cost benefit analysis for the appraisal of non-commercial services. Yet there is a need for elaboration of the rules that deal with jointness in costs and in revenues, and for extension of the appraisal scheme to permit multi-modal application. Government policy-makers should also address institutional barriers that may hinder the development of valuable alternative supply arrangements, and instigate a review of existing marginal services to see if they are all worthwhile.Institute of Transport and Logistics Studies. Faculty of Economics and Business. The University of Sydne

Privacy-Preserving Aggregation of Time-Series Data

The conference paper can be viewed at: http://www.isoc.org/isoc/conferences/ndss/11/proceedings.shtmlSession 9: PrivacyWe consider how an untrusted data aggregator can learn desired statistics over multiple participants’ data, without compromising each individual’s privacy. We propose a construction that allows a group of participants to periodically upload encrypted values to a data aggregator, such that the aggregator is able to compute the sum of all participants’ values in every time period, but is unable to learn anything else. We achieve strong privacy guarantees using two main techniques. First, we show how to utilize applied cryptographic techniques to allow the aggregator to decrypt the sum from multiple ciphertexts encrypted under different user keys. Second, we describe a distributed data randomization procedure that guarantees the differential privacy of the outcome statistic, even when a subset of participants might be compromised.published_or_final_versio

OncoLog Volume 53, Number 03, March 2008

In Search of the Answer DiaLog: Mapping the Cancer Genome, by Gordon Mills, MD, PhD, Director, Kleberg Center for Molecular Markers, Chair, Department of Systems Biology House Call: The Basics of Biopsieshttps://openworks.mdanderson.org/oncolog/1168/thumbnail.jp

Vitamin supplementation for prevention of mother-to-child transmission of HIV and pre-term delivery: a systematic review of randomized trial including more than 2800 women

BACKGROUND: Observational studies have suggested that low serum vitamin levels are associated with increased mother-to-child transmission (MTCT) of HIV and increased preterm delivery. We aimed to determine the efficacy of vitamins on the prevention of MTCT and preterm delivery by systematically reviewing the available randomized controlled trials [RCTs]. We conducted systematic searches of 7 electronic databases. We extracted data from the RCTs independently, in duplicate. RESULTS: We included 4 trials in our review. Of the three trials on Vitamin A, two suggested no difference in MTCT, while the third and largest trial (n = 1078) suggested an increased risk of MTCT (Relative Risk 1.35, 95% Confidence Interval [CI], 1.11–1.66, P = 0.009). Two of the vitamin A trials addressed the impact of supplementation on pre-term delivery; one suggested a benefit (RR 0.65, 95% CI, 0.44–0.94) and the other no difference. All three vitamin A trials found no significant effect on infant mortality at 1 year. Of the two trials that looked at multivitamin use, only one addressed the prevention of MTCT, and found a non-significant RR of 1.04 (95% CI, 0.82–1.32). Two of the multivitamin trials found no significant effects on pre-term delivery. The single multivitamin trial examining children's mortality at 1 year yielded a non-significant RR of 0.91 (95% CI, 0.17–1.17). CONCLUSION: Randomized trials of vitamins to prevent MTCT have yielded conflicting results without strong evidence of benefit and have failed to exclude the possibility of harm

OncoLog Volume 45, Number 05, May 2000

Early Detection of Melanoma Spread May Increase Survival Benefits of Adjuvant Therapy No Easy Answers: Women at Increased Risk for Breast Cancer Face Difficult Choices DiaLog: Understanding Risk: A Prerequisite for Making Informed Decisions, by Gordon B. Mills, MD, PhD, Chairman, Department of Molecular Therapeutics House Call: Looking for Trouble: How to Spot Signs of Melanoma Protocols: Melanoma Clinical Trials Biochemotherapy Means Hope for Patients with Advanced Melanomahttps://openworks.mdanderson.org/oncolog/1085/thumbnail.jp

Environmental Impacts of the Border Wall

On January 25, 2017, during his first week in office, President Donald Trump signed an Executive Order calling for the “immediate construction of a physical wall on the southern border” of the United States . Such a wall would span more than one thousand miles, across many different habitats and many different communities . Before a wall will be built, numerous questions must be answered: Which environmental laws apply? How might all this work? On February 16, ELI convened experts to discuss how environmental law and policy may interact with the Executive Order, and to spark discussion about important environmental resources and communities along the border . Below, we present a transcript of the event, which has been edited for style, clarity, and space considerations