Microbial susceptibility of various polymers and evaluation of thermoplastic elastomers with antimicrobial additives

The incursion of microbial growth on polymeric products can deteriorate their performance and lead to the development of undesirable staining and odors. A growing trend in the industry has aimed to reduce microbial populations on high-touch surfaces via the use of antimicrobials to protect material aesthetics and durability or to prevent the spread of pathogenic microorganisms. In this study, a variety of plastic substrates (30 unique polymer compounds), including poly(acrylonitrile-co-butadiene-co-styrene), poly(butylene terephthalate), poly(etherimide), various thermoplastic elastomers (TPEs), poly(carbonates), and poly(amides), were screened for susceptibility to microbial attack using American Society for Testing and Materials (ASTM) G21 (fungi susceptibility), Japanese Industrial Standard (JIS) Z2801, and modified ASTM E1428-15a (bacterial susceptibility) test standards. TPEs were determined to be most susceptible to microbial attack under the appropriate environmental conditions. Subsequent studies assessed the use of an antimicrobial additive, zinc pyrithione (ZPT), for potential efficacy in a variety of TPE blends for diverse target market applications. ZPT proved to be very effective in protecting TPEs, reducing Staphylococcus aureus and Escherichia coli populations by 99.9% or more in JIS Z2801 testing and inhibiting fungal growth (rating = 0) according to the ASTM G21 standard.     

Differences in PARP Inhibitors for the Treatment of Ovarian Cancer: Mechanisms of Action,Pharmacology, Safety,and Efficacy

Poly(ADP-ribose) polymerases (PARP) are proteins responsible for DNA damage detection and signal transduction. PARP inhibitors (PARPi) are able to interact with the binding site for PARP cofactor (NAD+) and trapping PARP on the DNA. In this way, they inhibit single-strand DNA damage repair. These drugs have been approved in recent years for the treatment of ovarian cancer. Although they share some similarities, from the point of view of the chemical structure and pharmacodynamic, pharmacokinetic properties, these drugs also have some substantial differences. These differences may underlie the different safety profiles and activity of PARPi.     

Left ventricular diastolic filling alterations in subjects with mitral valve prolapse: a Doppler echocardiographic study

To assess left ventricular diastolic filling in mitral valve prolapse (MVP), we studied 22 patients with idiopathic MVP and 22 healthy controls matched for sex, age, body surface area and heart rate. A two-dimensional, M-mode and Doppler echocardiographic examination was performed to exclude any cardiac abnormalities. The two groups had similar diastolic and systolic left ventricular volumes, left ventricle mass and ejection fraction. Doppler measurements of mitral inflow were: E and A areas (the components of the total flow velocity-time integral in the early passive period of ventricular filling, E; and the late active period of atrial emptying, A), the peak E and A velocities (cm.s-1), acceleration and deceleration half-times (ms) of early diastolic rapid inflow, acceleration time of early diastolic flow (AT), total diastolic filling time (DFT) (ms), and the deceleration of early diastolic flow (cm.s-2). From these measurements were calculate: peak A/E ratio (A/E), E area/A area, the early filling fraction, the atrial filling fraction, AT/DFT ratio. All the Doppler measurements reported are the average of three cardiac cycles selected at end expiration. The mean peak A velocity, A/E velocity ratio, deceleration half time and atrial filling fraction were each significantly higher for subjects presenting a MVP (60 +/- 12 cm.s-1 vs 49 +/- 14, P < 0.008; 98 +/- 13% vs 64 +/- 12%, P < 0.0001; 120 +/- 36 ms vs 92 +/- 11, P < 0.002; 0.45 +/- 0.14 vs 0.36 +/- 0.08, P < 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)     

On the effect of receiver estimation error upon channel mutual information

Our goal in this paper is to study the effect of the receiver structure upon the achievable data rates. We consider transmission of linearly precoded data symbols over a frequency selective block fading multiple input multiple output (MIMO) wireless channel. To encompass a number of transmission schemes, we study this problem utilizing affine precoding, which is a unified model of linearly precoded data symbols with superimposed training. We focus on Bayesian receivers that estimate both the unknown fading coefficients and the data symbols. The receiver may adopt either of the following strategies to retrieve the data symbols: strategy (i) the receiver obtains joint Bayesian channel and symbol estimates, strategy, (ii) the receiver obtains a Bayesian channel estimate initially and the channel measurement is utilized to estimate the data symbols. For both strategies, we provide lower bounds on the mutual information between the data symbols and their corresponding estimates, and we relate these bounds to the symbol Cramer-Rao bound (CRB) matrices. In contrast to strategy (ii), for strategy (i) the lower bound does not depend on either the channel estimate or the covariance of the channel estimation error. For strategy (ii) we show that asymptotically (as the size of the transmission block grows) there is no loss of information after the maximum a posteriori (MAP) estimate of Gaussian symbols. We also provide guidelines to design affine precoders that maximize the derived lower bounds under the total average transmit power constraint.     

Obesity, hypertension and atherosclerosis

OBJECTIVE: To determine the effect on oxygen saturation of instilling a saline bolus into artificial airways prior to suctioning, as measured by pulse oximeter. DESIGN: Quasi-experimental, single-case, counterbalanced design. SETTING: The surgical, medical and coronary intensive care units of a federal, teaching medical center. SUBJECTS: Subjects were 40 men, more than 40 years old, in need of intensive care nursing and mechanical ventilation. INTERVENTIONS: Subjects were suctioned as needed for 24 hours. A 5-mL saline bolus was instilled every other time the subject was suctioned. Outcome measurements were done immediately before and after suctioning and at 1-minute intervals for 5 minutes after suctioning. MAIN OUTCOME MEASURES: Noninvasive oxygen saturation values. RESULTS: The instillation of a saline bolus was found to have an adverse effect on oxygen saturation that worsened over time. Significant changes in oxygen saturation as a result of saline bolus instillation were found at 2,3,4 and 5 minutes after instillation. CONCLUSIONS: These results indicate that instilling saline prior to suctioning has an adverse effect on oxygen saturation. These results support the recommendation that the practice of instilling saline prior to suctioning should be abandoned as a routine procedure. More study is needed to investigate whether a specific group of patients may actually benefit from this procedure.     

On the power efficiency of cooperative broadcast in dense wireless networks

A fundamental problem in large scale wireless networks is the energy efficient broadcast of source messages to the whole network. The energy consumption increases as the network size grows, and the optimization of broadcast efficiency becomes more important. In this paper, we study the optimal power allocation problem for cooperative broadcast in dense large-scale networks. In the considered cooperation protocol, a single source initiates the transmission and the rest of the nodes retransmit the source message if they have decoded it reliably. Each node is allocated an-orthogonal channel and the nodes improve their receive signal-to-noise ratio (SNR), hence the energy efficiency, by maximal-ratio combining the receptions of the same packet from different transmitters. We assume that the decoding of the source message is correct as long as the receive SNR exceeds a predetermined threshold. Under the optimal cooperative broadcasting, the transmission order (i.e., the schedule) and the transmission powers of the source and the relays are designed so that every node receives the source message reliably and the total power consumption is minimized. In general, finding the best scheduling in cooperative broadcast is known to be an NP-complete problem. In this paper, we show that the optimal scheduling problem can be solved for dense networks, which we approximate as a continuum of nodes. Under the continuum model, we derive the optimal scheduling and the optimal power density. Furthermore, we propose low-complexity, distributed and power efficient broadcasting schemes and compare their power consumptions with those-of-a traditional noncooperative multihop transmission     

Experimental determination of Anammox decay coefficient

This paper describes an experimental method used to evaluate the anaerobic ammonium oxidation (Anammox) decay coefficient by means of a batch test. The test was carried out using an experimental procedure based on manometric measurements of the dinitrogen gas that is produced by the Anammox process. The accuracy of the procedure had previously been assessed, and the method was used to determine the specific Anammox activity (SAA mg N₂‐N g VSS^?1 d^?1,) and the maximum nitrogen production rate (MNPR, NmL N₂ L^?1 d^?1) under several different conditions. A specific batch test, which lasted for 148 days, was performed to assess the decay coefficient. The activity decrease was monitored and the estimated value of the decay coefficient was found to be 0.0048 d^?1 at 35 °C, for which the corresponding half‐life time of the Anammox biomass was 145 days. This value is higher than other values reported in the literature, but in accordance with the slow growth rate of the Anammox bacteria. Copyright © 2009 Society of Chemical Industry     

Mesh design in finite element analysis of post-buckled delamination in composite laminates

The role of mesh design in the post-buckling analysis of delamination in composite laminates is addressed in this paper. The determination of the strain energy release rate (SERR) along the crack front is central to the analysis. Frequently, theoretical analysis is limited to treatment of the problem in two dimensions, since considerable complexity is encountered in extending the analysis to three dimensions. However, many practical problems of embedded delamination in composite laminates are inherently three-dimensional in nature. Although in such cases, the finite element (FE) method can be employed, there are some issues that must be examined more closely to ensure physically realistic models. One of these issues is the effect of mesh design on the determination of the local SERR along the delamination front. There are few studies that deal with this aspect systematically. In this paper, the effect of mesh design in the calculation of SERR in two-dimensional (2D) and three-dimensional (3D) FE analyses of the post-buckling behavior of embedded delaminations is studied and some guidelines on mesh design are suggested. Two methods of calculation of the SERR are considered: the virtual crack closure technique (VCCT) and crack closure technique (CCT). The 2D analyses confirm that if the near-tip mesh is symmetric and consists of square elements, then the evaluation of the SERR is not sensitive to mesh refinement, and a reasonably coarse mesh is adequate. Despite agreement in the global post-buckling response of the delaminated part, the SERR calculated using different unsymmetrical near-tip meshes could be different. Therefore, unsymmetrical near-tip meshes should be avoided, as convergence of the SERR with mesh refinement could not be assured. While the results using VCCT and CCT for 2D analyses agree well with each other, these techniques yield different quantitative results when applied to 3D analyses. The reason may be due to the way in which the delamination growth is modeled. The CCT allows simultaneous delamination advance over finite circumferential lengths, but it is very difficult to implement and the results exhibit mesh dependency. Qualitatively, however, the two sets of results show similar distributions of Mode I and Mode II components of the SERR. This is fortunate, since the VCCT is relatively easy to implement.     

Muscle metastasis in a patient with epidermoid carcinoma of the lung

Diagnosis of vertically acquired human immunodeficiency virus (HIV) infection is often difficult because of transplacentally acquired maternal antibodies. The polymerase chain reaction (PCR) test is commercially available and has high sensitivity and specificity. To evaluate the usefulness of PCR testing in the early diagnosis of perinatally acquired HIV infection, we reviewed records of 122 children having follow-up in the Northeast Florida Pediatric AIDS Program. Seventy-two children were excluded for various reasons. Of the remaining 50 children, 37 had PCR testing. In 5 children, the initial PCR test was done at > 18 months of age. Results of PCR testing were positive in 8 of 13 (62%) at birth, 12 of 18 (67%) by 1 month of age, 18 of 23 (78%) by 2 months of age, and 20 of 24 (83%) by 3 months of age. In 24 of 27 (85%), results were positive by the time the children reached 4 months of age. Our data suggest that the PCR test is a useful tool for early diagnosis of vertically transmitted HIV infection.     

Efficacy and tolerability of brodimoprim od versus norfloxacin bid in the treatment of bacterial urinary tract infections

The efficacy and tolerability of brodimoprim OD versus norfloxacin BID were studied in patients affected by bacterial urinary tract infections. The study was performed in 203 patients divided into two parallel randomized groups orally given either brodimoprim 400 mg OD on the first day followed by 200 mg OD for 2 days, or norfloxacin 400 mg BID respectively. The efficacy of treatment was evaluated by the bacterial cultures, tolerability, analysis of signs and symptoms, a complete physical examination and from laboratory data. The results showed that brodimoprim and norfloxacin in the majority of patients resulted in a reduction of fever and symptoms caused by the infective process. Of the 103 patients enrolled in the brodimoprim OD group, 99 had a complete course of therapy with a positive outcome. There was only one case of failed treatment and 3 cases which could not be evaluated because of voluntary interruption of treatment. Of the 100 patients treated with norfloxacin BID, 94 completed therapy with a positive clinical outcome and there were 4 cases of treatment failure. Thus the efficacy of brodimoprim OD appears comparable to that of norfloxacin BID in the treatment of urinary tract infections.