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Perpendicularly oriented lamellar forming block copolymers are promising candidates for the fabrication of high aspect ratio nanostructures either by means of direct pattern transfer to the underlying substrate or by sequential infiltration processes. In this work, highly ordered lamellar grains (ξ ＞ 500 nm) were produced by thermally treating the samples at high temperature (Ttarget ＞ 250 °C) in a Rapid Thermal Processing (RTP) machine. The variation of the lateral order of the nanostructures during the annealing process was investigated in detail, by decoupling the effect of the transients and of the isothermal step of the thermal treatment. Moreover, the self-assembly process was studied as a function of the annealing time and temperature in order to identify the processing parameters that maximize the lateral order avoiding, and at the same time, any degradation of the macromolecules. From this study the activation energy (Ea∼ 55 kJ mol−1) of the lamellar grain coarsening process on featureless substrates was determined. The specific process conditions that promote the self-assembly of lamellar thin films reaching a level of lateral order that is suitable for nanostructure fabrication were established. [ABSTRACT FROM AUTHOR]

Tailoring surface energies is the key factor to control the orientation of nanoscopic structures in thin block copolymer (BCP) films. In the general frame of the “grafting to” approach, this paper reports on the use of Rapid Thermal Processing (RTP) technology to perform flash grafting reactions of a hydroxyl terminated poly(styrene-r-methylmethacrylate) random copolymer to the activated silicon wafer surface. The perpendicular orientation of the cylindrical morphology of an asymmetric PS-b-PMMA block copolymer is achieved when the thickness of the random copolymer layer is higher than 6.0 nm. The grafting time to achieve this thickness reduces from about 750 s, when the RTP grafting process is performed at 230 °C, to 15 s at 310 °C. For a symmetric PS-b-PMMA block copolymer, the perpendicularly oriented lamellar morphology is obtained when the random layer thickness is higher than 3.5 nm, that is after 60 s RTP grafting time at 250 °C. In addition, TGA-GC-MS analysis indicates that a chain structural reorganization, which occurs during the RTP treatment at high temperature, affords a more stable film structure without changing its surface characteristics. In conclusion, the RTP technology allows the “grafting to” approach to be successfully integrated into the next generation lithographic processes and affords the unprecedented opportunity to study the grafting of macromolecules on time scales and in temperature ranges that have never been explored before, shedding new light on the early stages and on the dynamics of these processes. [ABSTRACT FROM AUTHOR]

Self-assembling block copolymers generate nanostructured patterns which are useful for a wide range of applications. In this paper we demonstrate the capability to control the morphology of the self-assembling process of PS-b-PMMA diblock copolymer thin films on unpatterned surfaces by means of fast thermal treatment performed in a rapid thermal processing machine. The methodology involves the use of radiation sources in order to rapidly drive the polymeric film above the glass transition temperature. Highly ordered patterns were obtained for perpendicular-oriented cylindrical and lamellar PS-b-PMMA block copolymers in less than 60 s. This approach offers the unprecedented opportunity to investigate in detail the kinetics of the block copolymer self-assembly during the early stages of the process, providing a much deeper understanding of the chemical and physical phenomena governing these processes. [ABSTRACT FROM AUTHOR]

Objectives: To propose an objective approach in order to determine the number of beds required for a hospital department by considering how recruitment fluctuates over time. To compare this approach with classical bed capacity planning techniques.Methods: A simulated data-based evaluation of the impact that the variability in hospital department activity produces upon the performance of methods used for determining the number of beds required. The evaluation criteria included productive efficiency measured by the bed occupancy rate, accessibility measured by the transfer rate of patients due to lack of available beds and a proxy of clinical effectiveness, by the proportion of days during which there is no possibility for unscheduled admission.Results: When the variability of the number of daily patients increases, the Target Occupancy Rate favors productive efficiency at the expense of accessibility and proxy clinical effectiveness. On the contrary, when the variability of the department activity is marginal, the Target Activity Rate penalizes the proxy of clinical effectiveness, and the Target Occupancy Rate underoptimizes productive efficiency. The method we propose led to a superior performance in terms of accessibility and proxy of clinical effectiveness at the expense of productive efficiency. Such a situation is suitable for intensive care units. In the case of other departments, a weighting procedure should be used to improve productive efficiency.Conclusions: This approach could be considered as the first step of a family of methods for quantitative healthcare planning. [ABSTRACT FROM AUTHOR]

Rapid cycling is a relatively unusual presentation of bipolar affective disorder in the elderly Four cases or rapid-cycling affective disorder (RCAD) in elderly women (aged 78-86 yr) are presented. Two patients began their bipolar illness in adulthood (aged 30 and 49 yr), and rapid cycles appeared secondarily in their elderly years (82 and 76 yr). The other two began their illness immediately with rapid cycles respectively at the age of 62 and 66. Added to the nine cases of RCAD in the elderly previously reported in the literature, a meta-analysis conducted on this small sample suggests that immediate entry in rapid cycles seems more likely to be associated with a late occurrence of bipolar illness (after 60 years of age) (P = .0035, Fisher's Exact Test, two-tailed), and that very short cycles (<2 weeks each) are more likely to be associated with female gender (P = .0047, Fisher's Exact Test, two-tailed). Despite the small size of the sample, these results give some arguments to the hypothesis that RCAD is not a homogeneous syndrome but could be considered as a pattern of evolution, as well as clinical subtype, of the bipolar illness. (J Geriatr Psychiatry Neurol 1997; 10:105-110). [ABSTRACT FROM PUBLISHER]