A catheter coating consisting of polydimethylsiloxane (PDMS) mixed with powdered metals silver and zinc has been investigated. The coating is easily applicable to existing silicone devices and effective in inhibiting the formation of biofilm. Following manufacturing of the coating, its surface materials characteristics were analyzed through scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). The antibacterial properties of the coating were investigated by applying a thin film to the surface of a standard silicone catheter. A unique coating formulation of zinc and silver was found to inhibit biofilm and planktonic growth of E. coli over a six-day period, seemingly related to the release of heavy metal ions, generation of electric fields, hydrogen peroxide formation or combinations of these effects. Open-circuit cell potential for a zinc and silver foil was measured to be 1.2 V and 0.97 V within a deionized (DI) water and urine solution, respectively. Zone of inhibition experimental results suggest the possibility of silver ion diffusion when using mixed metals since bacteria formation is inhibited beyond the sample edge. Hydrogen peroxide measurements were taken over a period of 13 days for all samples. Samples containing zinc were found to produce hydrogen peroxide, a known antimicrobial agent. Wettability measurements of samples showed that the introduction of active materials lead to an increase of hydrophilicity, potentially affecting bacterial adhesion.

Both commercial and experimental antibacterial urinary catheters were investigated for their efficacy in preventing planktonic growth and biofilm formation of Escherichia Coli bacteria in a synthetic urine solution. Experimental antibacterial catheters having thin (<500 µm) dispersions of Ag, Ag/Ag2O, or Zn/Ag2O in polydimethylsiloxane (PDMS) binder all exhibited significant antimicrobial activity, outperforming traditional commercial antibacterial catheters. All experimental catheters prevented planktonic growth of bacteria and did not exhibit biofilm formation during a six-day test period using a colony forming unit (CFU) measurement method. On the other hand, the best performing commercial catheters demonstrated efficacy for only 3 days in planktonic growth tests and formed multiple bacterial colonies in CFU measurements. The Zn/Ag2O/PDMS experimental catheter was the only catheter observed to produce hydrogen peroxide, a reactive oxygen species known to inhibit biofilm formation; lack of detectable hydrogen peroxide production by the Ag2O/PDMS and Ag/Ag2O/PDMS experimental catheters suggests that bactericidal action most likely arises from release of silver ions present in the PDMS coatings.

Catheter associated urinary tract infection (CAUTI) is a widespread complication within hospitals and nursing homes. A potential treatment is to use a biofilm-inhibiting catheter. In this paper, methods for creating a biofilm retardant catheter coating using silver, silver oxide, and/or zinc particles combined with polydimethylsiloxane (PDMS) are described. The coating was first applied to the outside surface of the catheter and then tested for its antimicrobial properties with respect to preventing planktonic and biofilm growth of Escherichia coli. A comparison of our “in house” created catheters was then made with commercially available antimicrobial urinary catheters.

Catheter acquired urinary tract infection (CAUTI) is a significant problem in the medical community. Interdisciplinary teams have coordinated to address this problem, yet there is still a need for an adequate solution. In this study, we investigate an electricidal solution by adopting electrochemically active materials that can be incorporated into a urinary catheter. Zinc and silver oxide powders deposited in the form of patterned electrodes on a thermoplastic substrate are shown to illustrate electricidal properties in urine, including the ability to produce electric fields, pH increases, as well as, formation of hydrogen peroxide. The newly developed samples show promising results for killing planktonic E. coli in a controlled setting.

The contact potential across the head-disk interface is investigated. AC voltage was applied to the disk surface using a mercury connector located at the top of the spindle, keeping the recording head grounded. The acoustic emission (AE) and touchdown sensor (TDS) amplitude was measured as a function of the DC offset voltage to determine the contact potential across the head-disk interface at which the AE and TDS signals, respectively, becomes a minimum. The contact potential across the head-disk interface is studied as a function of temperature, relative humidity, and wear of the head-disk interface.

In this investigation, we examine wear of thermal flying height control sliders as a function of DC bias voltage across the head–disk interface, relative humidity, and lubricant type. Wear tests were conducted using two different experimental setups, a load/unload tester, and a spin-stand tester with relative humidity control. Head wear was determined by measuring the change in the heater touch-down power (ΔTDP) before and after wear testing. After wear testing, selected recording heads were examined using atomic force microscopy and time of flight secondary ion mass spectrometry to investigate wear and deposit formation in the read/write region. Our results show that the polarity of the head–disk interface bias voltage and the relative humidity influence deposit formation and wear in the read/write region of recording heads.

The effect of slider bias voltage and humidity on wear at the head/disk interface is investigated. Wear of thermal flying height control sliders is studied as a function of head/disk bias voltage, relative humidity, and heater power. The electrostatic force and the contact potential at the head/disk interface is monitored before and after head wear using the non-contact Kelvin probe method.

In this investigation, we study head wear as a function of a dc bias voltage applied across the head-disk interface (HDI). Head-wear is determined by measuring the change in the heater touch-down power before and after 10 minute wear tests. It is found that applying a positive bias to the disk with respect to the slider results in reduced head wear.

We have characterized the magnetic reversal and thermal stability of bit-patterned media with a composite structure of [Co (0.25 nm)/Pd (0.7 nm)] 5 /Fe( X )/[Pd (0.7 nm)/Co (0.25 nm)] 5 , where X = 1, 1.5 , and 2 nm. For 25 nm diameter islands separated by 35 nm, the average thermal stability of the islands is confirmed by analyzing the time-dependent coercive fields. However, by further analyzing the time-dependent hysteresis loop shape, we find a broad distribution of the effective energy barriers. We quantitatively show that this energy barrier distribution arises primarily from the dipolar interactions in these densely packed arrays and not from intrinsic distributions.

Reliably erasing data from storage media (sanitizing the media) is a critical component of secure data management. While sanitizing entire disks and individual files is well-understood for hard drives, flash-based solid state disks have a very different internal architecture, so it is unclear whether hard drive techniques will work for SSDs as well.We empirically evaluate the effectiveness of hard drive-oriented techniques and of the SSDs' built-in sanitization commands by extracting raw data from the SSD's flash chips after applying these techniques and commands. Our results lead to three conclusions: First, built-in commands are effective, but manufacturers sometimes implement them incorrectly. Second, overwriting the entire visible address space of an SSD twice is usually, but not always, sufficient to sanitize the drive. Third, none of the existing hard drive-oriented techniques for individual file sanitization are effective on SSDs.This third conclusion leads us to develop flash translation layer extensions that exploit the details of flash memory's behavior to efficiently support file sanitization. Overall, we find that reliable SSD sanitization requires built-in, verifiable sanitize operations.