In recent decades, the negative effects of artificial light at night on natural ecosystems have attracted the attention of ecologists. Studies have shown that artificial light at night leads to a considerable reduction in insects and has a worrying impact on terrestrial ecosystems, including nocturnal insects (e.g. Lepidoptera) such as moths. Warm white light is generally expected to have a lower ecological impact compared with cold white light which has a higher proportion of blue light (< 500 nm). The aim of this study is to investigate the impact of three light emitting diode (LED) light sources with different spectral power distributions on the responses of the greater wax moth (Galleria mellonella) under controlled experimental settings. In this experiment, three light sources with different spectral power distribution and dark condition were used and the start response time, time active, time flap wings, time flap wings / time active, main activity area and stop area of the greater wax moth were investigated. The light treatment used were: (1) darkness (n = 13); (2) warm-white light (correlated color temperature of 2675 K, n = 12); (3) white light (4070 K, n = 4); (4) cold white light (6200 K, n = 8). The experiment was performed in a rectangular light-tight box under controlled conditions. Main activity area showed significant difference between warm-white light and cold white light. With cold white light, a larger proportion of the moths were active in the area with the highest light levels, while the main activity area in the warm white light was in the zone with the lowest light levels. Other variables, however, did not show significant differences. The conclusion is that warm white light had a lower ecological impact than cold white light due to a larger proportion of moth is attracted to areas with stronger light. The results support the notion that in outdoor environments, warm white LEDs (maximum 3000 K) should be preferred compared to cold white light LEDs (over 3000 K), to reduce the impact on insects such as moths. The low correlated color temperature light sources used outdoors deserves more in-depth development and research.

We hypothesized that the presence of monoclonal free light chains (FLC) in the serum of patients with monoclonal gammopathy of undetermined significance (MGUS) is a marker of clonal evolution and a risk factor for progression. Forty-seven patients with MGUS and documented progression to myeloma or related malignancy were compared with 50 age- and gender-matched patients with MGUS and no evidence of progression after 5 or more years of follow-up. The presence of an abnormal kappa/lambda FLC ratio in the serum was associated with a higher risk of MGUS progression (relative risk 2.5; 95% confidence interval: 1.6-4.0; P < 0.001).

No description available.

At present, light pollution is one of the fastest growing types of environmental pollution, mainly due to increased use of artificial light during the dark hours of the day. There are especially four factors that contribute to light pollution; glare,skyglow, light trespass and clutter. Digital billboards are becoming more common in urban environments and cause all these types of light pollution. The newest type of digital billboard shows a series of very bright images that change every few seconds. Although digital billboards become more common in the urban environment, there is very little research on how it affects people living adjacent to digital billboards. The majority of the research available is about how traffic safety is affected. It is important to study how traffic safety is affected, but it is an environment where people stay for shorter periods of time. Light, and light pollution, can affect people both physically and mentally, and therefore the lack of research on how the housing environment is affected must be addressed. The purpose of the study is to investigate how the living environment is affected by a digital sign, and if it is affected, how do residents relate to it? The results from the study can be used to discuss guidelines for how digital signs should be planned for urban environments to minimize discomfort. Prevention is important in order to avoid a negative impact on human health. To investigate whether light from digital billboard affects people's living environment, a case study with a quantitative approach was performed. The study was conducted in a residential area adjacent to a digital sign. The residents were contacted and asked to fill in a questionnaire with questions about their living environment and their attitude towards the digital sign. The results show that the resident living closest to the digital sign is affected the most. How the living environment is affected depends to a large extent on the placement of the sign in relation to the residence. Conclusions that can be drawn based on the results are that the respondents most affected live within a 30-degree angle seen from the sign. Many of the problems that arise due to digital billboards are due to lack of knowledge and shortcomings in planning. Lack of research and deficiencies in the signage programs make it difficult to plan suitable installations. To cause minimal discomfort, no digital signs should be placed directly in front of a residential building. / I dagsläget är ljusföroreningar en av de snabbast växande typerna av miljöföroreningar främst på grund av ökad användning av artificiellt ljus under dygnets mörka timmar. Det är framförallt fyra faktorer som bidrar till ljusföroreningar; bländning, himmelssken, ljusintrång och ljusansamlingar. Digitala skyltar blir allt vanligare i urbana miljöer och orsakar alla dessa typer av ljusföroreningar. Den nyaste typen av digitala skyltar visar en serie av väldigt ljusa bilder som byts med några sekunders mellanrum. Trots att digitala skyltar blir ett vanligare inslag i stadsmiljön finns det väldigt lite forskning om hur det påverkar människor som bor i anslutning till digitala skyltar. Majoriteten av forskningen som finns handlar om hur trafiksäkerheten påverkas. Det är viktigt att studera hur trafiksäkerheten påverkas men det är en miljö där människor vistas under kortare perioder. Ljus, och ljusföroreningar, kan påverka människor både fysiskt och psykiskt och därför måste bristen på forskning om hur boendemiljön påverkas åtgärdas. Syftet med studien är att undersöka hur boendemiljön påverkas av en digital skylt, och om den påverkas, hur förhåller de boende sig till det. Resultaten från studien kan användas för att diskutera riktlinjer för hur digitala skyltar ska planeras in i stadsmiljön för att minimera obehag. Att arbeta förebyggande är viktigt för att undvika en negativ påverkan på människors hälsa. För att undersöka om ljus från digitala skyltar påverkar människors boendemiljö utfördes en fallstudie med kvantitativ ansats. Studien utfördes i ett bostadsområde som låg i anslutning till en digital skylt. De boende kontaktades och ombads fylla i ett enkätformulär med frågor om sin boendemiljö samt attityd till den digitala skylten. Resultatet visar att de som bor närmast den digitala skylten påverkas mest. Hur boendemiljön påverkas beror till väldigt stor del på skyltens placering i förhållande till bostaden. Slutsatser som kan dras baserat på resultatet är att de respondenter som påverkas mest bor inom en 30-gradig vinkel sett från skylten. Många av de problem som uppstår på grund av digitala skyltar beror på okunskap och brister vid planeringen. Avsaknad av forskning och brister i de skyltprogram som finns gör det svårt att planera lämpliga installationer. För att orsaka minimalt obehag bör inga digitala skyltar placeras direkt framför ett bostadshus.

Call number: LD2668 .T4 1960 M33

This thesis is focused on the development of Raman micro-spectroscopy for label free imaging and discrimination of stem cells. The thesis is divided into six chapters. Chapter 1 gives an overview of the existing techniques used for molecular analysis of cells, with emphasis on methods that allow non-invasive label-free imaging. A literature review of the main relevant applications of Raman micro-spectroscopy for imaging cells was also included. Chapter 2 discusses the basic theoretical principles of Raman scattering and design of Raman micro-spectrometers. The practical aspects related to the design of an optimised Raman micro-spectrometer are presented in Chapter 3 along with experimental characterisation of its performance. The chapter concludes with examples of Raman spectral maps of endothelial cells. Chapter 4 and Chapter 5 present experimental results obtained by Raman micro-spectroscopy for molecular analysis of live neural and mesenchymal stem cells. In these investigations Raman spectroscopy was used to identify, image and quantify spectral markers for label-free discrimination between glial cells and their neural progeny. The potential of Raman micro-spectroscopy to measure timecourse molecular changes of individual bone nodules was demonstrated in Chapter 5. Future work and final conclusion are discussed in Chapter six of this thesis.

This thesis explores the dynamics of optomechanical systems, which use radiation pressure to couple together optical and mechanical modes. Such systems display dynamics ranging from the quantum to the classical, with a variety of applications including ground state cooling and precision measurements. In this thesis two different geometries are presented for such a system in the form of the ‘reflective’ and ‘dispersive’ systems. Different aspects of the dynamics are investigated numerically and analytically. Firstly the reflective system is introduced, which consists of a cavity formed from a fixed and a moveable mirror. The optical frequency of the cavity couples linearly to the moveable mirror’s position. This geometry is explored as the cavity is driven by a laser, revealing a range of dynamical states in the mirror as the drive frequency is varied. An alternative geometry is presented in the form of the dispersive optomechanical system. Two fixed mirrors with a partially transmitting membrane at the centre provide a cavity supporting two optical modes, that couple approximately linearly or quadratically to the membrane position, depending on where the membrane is fixed. The system is explored in both linear and quadratic coupling regimes. Quadratic coupling is explored for a single optical mode by selecting a high tunnelling rate through the membrane. The dynamics of the membrane are explored via a similar set of techniques to those applied to the reflective system. Linear coupling for two optical modes is explored in the regimes of blue and red detuning. First resolved sideband cooling is explored, providing an alternative approach ground state cooling (which has been explored for the reflective case). Finally, strongly driving the system over a range of coupling strengths induces classical behaviour, extending from limit cycle oscillations to chaotic motion.

Polymer distributed Bragg reflectors (DBRs) were prepared by spin-casting alternating layers of polystyrene (PS) and poly(vinylpyrrolidone) (PVP) from mutually exclusive (orthogonal) solvents. These all polymer photonic structures were prepared using a purpose built automated spin-coater system. Samples were prepared with targeted optical properties such as the wavelength position, intensity and bandwidth of reflection peaks. The wavelength position of the reflection peaks was controlled by the deposition spin-speed used during sample preparation. Reflectance was controlled by the number of layers deposited onto the sample. The bandwidth was increased by chirping the layers in the photonic structure. Reflection bands were measured in the UV/visible region of the spectrum using two different (transmission and reflection mode) purpose built spectrometer set-ups. Measured reflection bands had narrow bandwidths between 10nm and 20nm. Chirping these photonic structures broadened the peaks to bandwidths of ~ 50nm. A 100 layer PVP/PS DBR had a total reflectance of 93 ± 1%. The wavelength of the reflection peaks from flat DBR samples blue-shifted when measured away from normal incidence. This was reduced when corrugating a DBR by wrinkling the films with mechanical strain. The wavelength of the reflection band from a corrugated DBR remained constant when the sample was rotated. Thus improving the angular dependence of the structures. Fourier transform infra-red spectroscopy was used to measure reflection bands which were between wavelengths of 1600 nm and 2700 nm. These reflection bands had narrow bandwidths between 40 nm and 60 nm. The largest reflectance measured within the infra-red spectra was 80 ± 1% from a 50 layer PVP/PS DBR. A modified optical transfer matrix method was used to model the optical properties of the DBRs. Changes in the refractive index contrast (between 0.020 and 0.028 for 30 layer PVP/PS DBRs) were needed to fit the model to the measured UV/visible spectra. It was concluded that trapped solvent (from sample preparation) was lowering the refractive indices of the layers. The polymer-polymer interface widths of spin-cast polymer multi-layers were measured using neutron reflectivity. Each polymer-polymer interface width was less than 1nm throughout the DBR samples. The polymer multi-layer samples were measured using time of flight secondary ion mass spectrometry (TOF-SIMS). An Ar2000+ sputtering source was used to etch through the multi-layer samples. It was concluded that the thickness of spin-cast films did not change when preparing a multi-layer structure. However, other techniques, such as ellipsometry, are more suitable for measuring the thickness of films. The TOF-SIMS technique was unable to measure polymer-polymer interface widths in multi-layer samples. This was due to the sputtering beam roughening/mixing the polymers at the interfaces. It was concluded that PVP/PS DBRs could be used as inexpensive narrowband reflectors/filters. However, alternative polymer systems may be more useful for other applications which require a greater reflectance. This includes creating resonant cavities to improve the efficiency of optical devices (such as LEDS and solar cells). The results and techniques from these experiments are useful for further development in polymer photonic structures and polymer multi-layer devices.

No description available.

No description available.