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The development of large-scale syntheses of two beta-site amyloid precursor protein cleaving enzyme (BACE) inhibitors is described. New methodologies were discovered to overcome safety and scalability problems with existing procedures. The sterically hindered quaternary, neopentyl stereocenter was formed in high diastereoselectivity by the addition of a carbamoyl anion to an N-sulfinyl ketimine. An aryl nitrile was installed by a palladium- and cyanide-free electrophilic cyanation affected by transnitrilation of an arylmagnesium derivative with dimethylmalononitrile. A safe route to an oxetanylmethylamine side chain was devised based on diethyl malonate and dibenzylamine starting materials. A mild enamine fluorination was developed for the synthesis of a fluoroisobutylamine side chain.

Achieving environmental sustainability by improving the urban microclimate is a key principle in mitigating the urban heat island (UHI) effect. This study aimed to (a) investigate the outdoor thermal comfort by establishing Heat Index (HI) values to identify thermal hot spots and (b) model green infrastructure possibilities to alleviate UHI in Colombo urban metropolitan in Sri Lanka using ENVImet climate model. Daytime temperature and humidity values of 14 urban locations were collected to determine HI to recognize thermal urban hotspots in Colombo area. A pretested comprehensive random-stratified questionnaire survey has been conducted to appraise the thermal discernment of the general public. ENVImet microclimate model was accompanied to test the temperature reduction levels in different bioclimatic green infrastructure scenarios [Two belts (R1), three belts (R2), four belts (R3), five belts (R4)] in the selected study site. Five sites (Borella, Colombo Fort, Maradana, Wellawaththa, Liberty junction) were identified as thermal hotspots in Colombo metropolitan. HI values were fluctuated within 33.82–40.35 °C range and the highest average day time HI value was observed at Maradana (40.35 °C) and the lowest HI was observed at Thummulla (33.82 °C). Survey results revealed that 89.3% people are affected with thermal uncomfortability and 5% were affected with heat-related skin diseases. Inserting trees into curbsides (R4) reduced temperature remarkably by 2.07 °C in the urban metropolitan. Therefore, the proposed green infrastructure scenario has proved to be the most suitable way to improve the thermal comfort conditions of urban environment, as it can reduce the UHI effects.

High performance polymer dielectrics are a key component for printed electronics. In this work, organo-soluble polymers of intrinsic microporosity (PIMs) are reported for the first time to demonstrate desirable dielectric properties with a high permittivity (or κ), heat resistance, and low dielectric loss simultaneously. Due to the highly dipolar sulfonyl side groups (4.5 D) and rigid contorted polymer backbone, a sulfonylated PIM (SO2-PIM) enabled friction-free rotation of sulfonyl dipoles in the nanopores. As such, an optimal balance between relatively high κand low dielectric loss is achieved in a broad temperature window (−50–200 °C). For example, the discharged energy density reached 17 J cm−3with κ= 6.0. The discharge efficiency was 94% at 150 °C/300 MV m−1and 88% at 200 °C/200 MV m−1. Furthermore, its application as a high-κgate dielectric in field effect transistors (FETs) is demonstrated. With the bilayer SO2-PIM/SiO2gate dielectric, InSe FETs exhibited a high electron mobility in the range of 200–400 cm2V−1s−1, as compared to 40 cm2V−1s−1for the bare SiO2-gated InSe FET. This study indicates that highly dipolar PIMs with a rigid polymer backbone and large free volume are promising as next generation gate dielectric materials for printed electronics.

Music Genres are labels created by humans to classify music into different groups according to the audible features. Even though western music has different characteristics to differentiate genres, Sri Lankan music does not belong to these categories. Sri Lankan music has had multiple different influences over the years. This paper discusses a mechanism to identify the foreign influence on Sri Lankan music. There are five basic categories of music is considered in the research. They are: Inspired by Indigenous music (Jana Gee), Influenced from Ragadari music (Classical), Influenced from the Indian film music (Indian), Influenced from Western Music (Western), and Influenced from Portuguese Music (Baila). The dataset was created by gathering and analyzing research done by Sri Lankan Music experts. The dataset was trained and tested using six audio features, Spectral Bandwidth, Spectral Centroid, Spectral Contrast, Spectral Flatness, Spectral Roll-off, and Zero Crossing Rate. The dataset was trained and tested with five Machine Learning models and the Artificial Neural Network model achieved the best results with the most accuracy of 88.81% for differentiating Classical and Baila Genres.

The first beach nourishment project in Sri Lanka was carried out in 2012 over a 1.8-km stretch in the Uswetakeiyawa area by the Coast Conservation Department. About 300,000 m3of offshore sand in the Indian Ocean was pumped using a dredging vessel for the nourishment. Three breakwaters were constructed nearly 1 year after the beach nourishment. This research was carried out to analyze the performance of the above soft and hard engineering coastal protection strategies. Beach profiles and grain size data were collected over a 1-year period. This monitoring program covered entire seasonal cycles with a comparison to the pre-nourishment beach profiles. Satellite images were also analyzed spanning much larger time periods from 2010 to 2015. Beach profile data indicated both sand accretion and erosion in the nourished area. However, the variations of sand deposition showed enhancement of the sand volume. Satellite images indicated the irregular changes of the beach profiles after the construction of breakwaters. The field observations and calculated relationships of the breakwaters demonstrated either subdued salient or gap erosion at the specific locations of the nourished beach. In this study, no permanent or periodic tombolo formations were observed at Uswetakeiyawa beach. The lack of sediment supply from longshore currents and the high-energy cross-shore monsoon currents can enhance coastal erosion related to the presence of the breakwater.

The Alagaddupama Sutta is the 22nd discourse of the Majjhima-nikaya of the Pali canon. In the sutta itself it is mentioned that the Buddha’s delivery of this discourse was necessitated by the need to refute a wrong view held by one of his disciples named Arittha. Parallel versions of the sutta are found preserved in the Chinese agamas. The two main similes used in the sutta, those of the snake and of the raft, are referred to in the scriptures of a number of non-Theravada Buddhist traditions as well, showing that the Buddhist doctrine represented in it is early and authentic and the message contained in the sutta was considered to be extremely significant by many early Buddhist traditions. The Alagaddupama Sutta shows the Buddha’s role as one of the earliest thinkers in the history of philosophy who engaged in a critique of the craving for metaphysics and dogma frequently exhibited in those who propound worldviews. The Buddha did not value a belief or a worldview on grounds of the logical skill with which it was constructed but on grounds of the transformative effect it could have on the character of an individual and the sense of wellbeing it could promote. There are several discourses of the Pali canon which give prominence to this aspect of the Buddha’s teaching. Among them the Brahmajala Sutta of the Digha-nikaya and the Atthakavagga of the Suttanipata need special mention. The Buddha is seen to have consistently avoided engagement in speculative metaphysics, pointing out that the goal of his teaching goes beyond all such engagement. The Buddha himself distinguished his own worldview as a Teaching in the Middle (majjhena) avoiding the common tendency of humankind to be trapped by either of the two extremes, Eternalism or Annihilationism. These distinctive standpoints of the Buddha are all seen to be amply represented in the Alagaddupama Sutta.

Synthesis of large-area hexagonal boron nitride (h-BN) films for two-dimensional (2D) electronic applications typically requires high temperatures (∼1000 °C) and catalytic metal substrates which necessitate transfer. Here, analogous to plasma-enhanced chemical vapor deposition, a nonthermal plasma is employed to create energetic and chemically reactive states such as atomic hydrogen and convert a molecular precursor film to h-BN at temperatures as low as 500 °C directly on metal-free substrates—a process we term plasma-enhanced chemical film conversion (PECFC). Films containing ammonia borane as a precursor are prepared by a variety of solution processing methods including spray deposition, spin coating, and inkjet printing and reacted in a cold-wall reactor with a planar dielectric barrier discharge operated at atmospheric pressure in a background of argon or a mixture of argon and hydrogen. Systematic characterization of the converted h-BN films by micro-Raman spectroscopy shows that the minimum temperature for nucleation on silicon-based substrates can be decreased from 800 to 500 °C by the addition of a plasma. Furthermore, the crystalline domain size, as reflected by the full width at half-maximum, increased by more than 3 times. To demonstrate the potential of the h-BN films as a gate dielectric in 2D electronic devices, molybdenum disulfide field effect transistors were fabricated, and the field effect mobility was found to be improved by up to 4 times over silicon dioxide. Overall, PECFC allows h-BN films to be grown at lower temperatures and with improved crystallinity than CVD, directly on substrates suitable for electronic device fabrication.

The Drude model is one of the most fundamental models used to understand the electronic carrier transport in materials, including recently discovered topological materials. Here, we present a magneto-transport study revealing the non-Drude transport behavior in a heterostructure of topological crystalline insulator (TCI) SnTe and band insulator PbTe which exhibits a nonsaturating linear magneto-resistance (MR) effect, a novel phenomenon widely observed in topological materials with gapless dispersion. It is shown that in the van der Pauw geometry in which the longitudinal and transverse magneto-resistances are measured to extract the magneto-conductivity, the two-band Drude model is not sufficient to self-consistently describe both the longitudinal and transverse magneto-conductivities. Furthermore, in the Corbino geometry, which directly measures the longitudinal magneto-conductivity σxx(B) for a straightforward comparison with the Drude model, the MR, 1/σxx(B), still reveals a large linear MR effect, in direct discrepancy with the Drude model. While shining further light on the multiple-carrier transport in TCI, this study highlights an unusual magneto-transport character of topological materials that challenges the standard Drude picture of electron transport.

Manipulating the electron spin with the aid of spin–orbit coupling (SOC) is an indispensable element of spintronics. Electrostatically gating a material with strong SOC results in an effective magnetic field which can in turn be used to govern the electron spin. In this work, we report the existence and electrostatic tunability of Rashba SOC in multilayer InSe. We observed a gate-voltage-tuned crossover from weak localization (WL) to weak antilocalization (WAL) effect in quantum transport studies of InSe, which suggests an increasing SOC strength. Quantitative analyses of magneto-transport studies and energy band diagram calculations provide strong evidence for the predominance of Rashba SOC in electrostatically gated InSe. Furthermore, we attribute the tendency of the SOC strength to saturate at high gate voltages to the increased electronic density of states-induced saturation of the electric field experienced by the electrons in the InSe layer. This explanation of nonlinear gate voltage control of Rashba SOC can be generalized to other electrostatically gated semiconductor nanomaterials in which a similar tendency of spin–orbit length saturation was observed (e.g., nanowire field effect transistors), and is thus of broad implications in spintronics. Identifying and controlling the Rashba SOC in InSe may serve pivotally in devising III–VI semiconductor-based spintronic devices in the future.

Noble metal nanoparticle cluster arrays (NCAs) are a novel class of engineered substrates for surface enhanced Raman spectroscopy (SERS), in which the noble metal nanoparticles interact on multiple length scales to create a multiscale E‐field cascade enhancement. In this work the role of the building block for the NCA performance is quantified. Periodic NCAs with constant cluster diameter (D= 200 nm) but variable nanoparticle diameter (d) and intercluster separation (Λ) were assembled on glass and their optical response and SERS enhancement were systematically characterized as a function of D, Λ, and d. An increase of d from 40 to 80 nm and simultaneous decrease of Λfrom 200 to 50 nm led to an improvement of the ensemble averaged SERS enhancement factor by a factor of up to ∼8. The coefficient of variation (cv) of the enhancement factors (G) is significantly lower for the d= 80 nm NCAs than for the d= 40 nm and d= 60 nm NCAs. Optimized (D= 200 nm, Λ= 50 nm, d= 80 nm) NCAs show the overall highest signal reproducibility of all investigated NCAs and random nanoparticle substrates and achieve effective single cell detection sensitivity.

Defined nanoparticle cluster arrays (NCAs) with total lateral dimensions of up to 25.4 μm × 25.4 μm have been fabricated on top of a 10 nm thin gold film using template-guided self-assembly. This approach provides precise control of the structural parameters in the arrays, allowing a systematic variation of the average number of nanoparticles in the clusters (n) and the edge-to-edge separation (Λ) between 1 < n< 20 and 50 nm ≤ Λ ≤ 1000 nm, respectively. Investigations of the Rayleigh scattering spectra and surface-enhanced Raman scattering (SERS) signal intensities as a function of nand Λ reveal direct near-field coupling between the particles within individual clusters, whose strength increases with the cluster size (n) until it saturates at around n= 4. Our analysis shows that strong near-field interactions between individual clusters significantly affect the SERS signal enhancement for edge-to-edge separations Λ < 200 nm. The observed dependencies of the Raman signals on nand Λ indicate that NCAs support a multiscale signal enhancement which originates from simultaneous inter- and intracluster coupling and |E|-field enhancement. The NCAs provide strong and reproducible SERS signals not only from small molecules but also from whole bacterial cells, which enabled a rapid spectral discrimination between three tested bacteria species: Escherichia coli, Bacillus cereus, and Staphylococcus aureus.

This study attempts to determine the type and relative frequency of muscle diseases contributing to floppy and hypotonic infants in Singapore.

We introduce the concept of low-resolution surface enhanced Raman spectroscopy (SERS) for cyanide as a potentially highly useful, cost-effective approach to detection and analysis for monitoring water contamination. We present high-sensitivity, low-resolution measurements of cyanide in water using a solid-state gold sol–gel substrate. These data suggest a sensitivity limit for low-resolution SERS detection of cyanide in water in the region of 10 ppb. Copyright © 2001 John Wiley & Sons, Ltd.

It is shown that low-resolution Raman spectroscopy (LRRS) satisfies the need for a highly useful, low-cost spectroscopic approach to both qualitative and quantitative analyses of organic systems. Until now, the disadvantage of using Raman spectroscopy has been the cost of the instrumentation. It is shown that when the application does not require high spectral resolution for analysis, LRRS can be used and implemented with low-cost multimode lasers and miniature low-resolution spectrometers, thus lowering the size, weight and cost of the instrumentation by an order of magnitude. First the implementation of LRRS is discussed, emphasizing a small portable instrument, then four applications are presented, each representative of a wide range of applications where LRRS is applicable. These results show that the use of LRRS provides the potential to bring Raman analyses out of the laboratory to the process floor and into the field for near real-time, on-site and, in many cases, in situ measurements, monitoring and identification. Copyright © 1999 John Wiley & Sons, Ltd.