Cheaper Alternatives Research Articles

Control of T-DNA Transfer from Agrobacterium tumefaciens to Plants Based on an Inducible Bacterial Toxin-Antitoxin System.

High-value pharmaceutical products are already successfully produced in contained facilities using Agrobacterium-mediated transient transformation of plants. However, transfection methods suitable for open field applications are still desirable as a cheaper alternative. Biosafety concerns related to the use of recombinant agrobacteria in an industrial transfection process include possible transformation or transfection of unintended hosts or spread of the genetically modified agrobacteria in the environment. In this paper, we explored a novel biocontrol approach resulting in greater biosafety of the transient expression process in plants. Our proposed solution involves inducible expression of Agrobacterium tumefaciens toxin PemK and antitoxin PemI that provides for strictly regulated T-DNA transfer from agrobacteria to plants. We also identified several other toxins from putative Agrobacterium toxin-antitoxin modules and demonstrate their potential usefulness in the control of Agrobacterium tumefaciens as a DNA vector.

Feasibility study about the use of element profiles determined by ED-XRF as screening method to authenticate coconut sugar commercially available

Financial gain is a main driver for committing food fraud and replacement of ingredients with cheaper alternatives is an easy way to do it. Coconut sugar is becoming popular as an alternative to beetroot or cane sugar due to its high mineral content and lower glycaemic index. As its market price is about twice as high as that of conventional sugar, coconut sugar may become target to fraudulent manipulation. The present work explores the feasibility of using energy-dispersive X-ray fluorescence as a screening tool to verify its authenticity. Mass fractions of P, Cl, S, K, Ca, Fe, Cu, Br, Rb, and Sr determined in eleven coconut, ten cane, and one beetroot sugar samples, purchased in Belgian, Spanish, Polish, and Italian supermarkets were used for discriminating the different sugars. On average, the mass fractions of all the mentioned elements were higher in coconut than in cane and beetroot sugars. Multivariate analysis of the elemental fingerprint by Soft Independent Modelling of Class Analogies was used for authentication purposes. Models constructed were characterised by zero false positives; three coconut sugars (27%) could not be classified as such, neither as cane sugars.

Study of YAG : Ce and Polymer Composite Properties for Application in LED Devices.

The cost of the rare-earth metal cerium means that preparation of YAG : Ce is expensive. To overcome this, the garnet could partially be replaced by cheaper alternatives, while retaining the original properties of YAG : Ce. Composites with different polymers such as polyethylene glycol diacrylate (M280) and dipentaerythrityl hexaacrylate (M600) were therefore studied. YAG : Ce and boron nitride were added into the polymer matrix in order to obtain composites with enhanced thermal conductivity, necessary for high-optical-density applications. The physical properties of the composites were measured by using XRD, DSC, SEM, and NMR, and the most important characteristics for LED materials such as emission, excitation, decay time and quantum efficiency were analyzed. An LED prototype was developed to test and demonstrate the composites for practical applications. That developed device exhibited optical properties very close to those comprising a commercial garnet prototype, which was also developed for comparison. The main advantage of the proposed technology is that by using 2 time less the amount of YAG : Ce, almost the same light output was obtained compared to commercial phosphors.

Antibacterial Activity of Extracts of Albizia lebbeck Against Staphylococcus aureus, Escherichia coli and Proteus mirabilis

Herbs and medicinal plants have widely been used as the first medicines. The development of new antibacterial drugs got more attention recently because of the continuous development of resistance of bacteria to the current antibiotics. Albizia lebbeck is a type of deciduous tree that has compound leaves, flat oblong fruit and round cream-colored seeds. It grows in wild and is also planted in many parts of South Asia and Africa. There is a significant amount of data to support the healing and curing properties of Albizia lebbeck. A lebbeck has been used in the treatment of various pain and inflammatory conditions in various traditions. Here we used the extracts of Albizia lebbeck against three different bacterial strains namely Staphylococcus aureus, Escherichia coli and Proteus Mirabilis. Methanol and Ethanol extracts were used to check their antibacterial activity. Results indicated that Albizia lebbeck showed growth inhibition pattern against the tested species, when compared with gentamicin. The results authenticated its traditional use and indicated promising potential of this plant to be developed as antibacterial agent. Further work is needed for isolation, structure elucidation and characterization of bioactive constituents responsible for this activity. These isolated natural products should be screened in vivo and in vitro for antibacterial activity and may be developed as cheap alternatives to costly synthetic antimicrobial agents available in market.

Feasibility of textile fabrics for strengthening of concrete column

Renovation and rehabilitation of concrete structures become inevitable when structures reach their service life. Rehabilitation or strengthening of concrete structures using fiber reinforced polymers and textile reinforced mortar are the most common and effective methodologies. However, these rehabilitation techniques are expensive hence cheaper alternatives need to be explored for sustainable concrete structures. Current research program was planned to investigate the efficiency and effectiveness of textile reinforced mortar using locally available textile fabrics on upgrading structural performance of concrete columns. Six locally available fabrics were characterized to select best fabrics for strengthening of concrete columns. Plain Concrete Columns (PCC) were strengthened using epoxy and mortar and selected fabrics with different number of layers. All specimens were tested under uniaxial compression. Results revealed that an increase in axial load carrying capacity ranging between 32% and 58% can be achieved using fabrics along with epoxy. On replacing epoxy with cement mortar, a further increase of up to 23% can be achieved under specific conditions. The use of three layers of textile fabrics might be considered effective as on addition of further layers, the strength gain is not significant. The presented results indicate that the use of textile fabrics may prove to be a promising method of upgrading column’s structural performance.

Production of bacterial cellulose from alternative cheap and waste resources: A step for cost reduction with positive environmental aspects

Bacterial cellulose (BC), an important biopolymer, has gained tremendous interest in several fields in the last few decades. Despite having the same chemical structure as plant cellulose, BC is superior in physical appearance and purity, as well as in mechanical, crystallinic, and biological properties for multiple applications. Despite these features, BC has limitations in production cost as well as physiological features. Notable limitations, including a non-bactericidal nature, low biocompatibility, and lack of conductive and magnetic properties, have been compensated through the development of composites using nanomaterials and polymers. Similarly, the limitation associated with cost has been reduced by developing new BC synthesis strategies, designing novel bioreactors, using genetically modified microbial species, and exploring alternative cheap fermentation media. Successful BC production has been reported from the use of industrial, confectionary, municipal and other wastes, including coconut water and fruit juices. Herein, we overview various efforts made thus far in identifying waste byproducts and inexpensive carbon sources for cost-effective BC production. It also provides information about the BC market and selling price, as well as techno-economic analysis of biotechnological BC production. This review article includes findings reported in the last few decades, and we hope it will be of great interest for readers as well as commercial BC producers.

Efficiently luminescent cuprous iodide complexes supported by novel N^P-chelating ligands: Synthesis, structure and optoelectronic performances

Phosphorescent cuprous complexes (1–6) with general formula CuI(N^P) (PPh3), where N^P = 2-(2′-diphenylphosphinophenyl)-1-phenyl-5-methoxybenzimidazole derivatives, have been designed and synthesized. The crystal structures of the neutral four-coordinated Cu(I) complexes are determined by single crystal X-ray diffraction. At 293 K, these complexes exhibit intense phosphorescence with exceptionally high photoluminescence quantum yields (up to 88.3%) and short decay times (4.8–55.2 μs). The emission maxima can be fine-tuned from 529 nm to 577 nm, depending upon the number and position of methoxy substituent on the N^P ligand. Especially, complex 5 exhibits phosphorescence (533 nm) with photoluminescence quantum yield of 70.5% and decay time of 19.5 μs, implying its potential to serve as a phosphor for organic light emitting diode (OLED). Solution-processed OLED incorporating complex 5 as dopant emitter achieves a maximum brightness of 7729 cd with CIE coordinates (0.4351, 0.5398), constituting a step further toward the design of cuprous complexes as cheap and environmental alternatives to the luminescent noble metal complex.

Evaluation of Capital Cost: Long Run Evidence from Manufacturing Sector

The article is directed to determine the most appropriate method for evaluating cost of capital of a manufacturing sector and, using the methodology, to perform a case study of Lithuanian manufacturing sector. For evaluation of cost of capital, calculation of Weighted Average Capital Cost was chosen, as literature analysis distinguished this method as the most widely accepted and used. Some changes were made to the methodology of WACC evaluation in order to adapt the method for countries, which do not contain liquid, mature financial markets, like using country’s credit ranking to assess risk premium and adding this premium to base premium for maturelly developed equity markets. The case study of Lithuanian manufacturing sector was performed for the period of 2001-2016. Empirical study revealed that required rate of return on separate WACC components evolved differently between the years of 2001-2016. Average annual return on equity for the period 2001-2016 was 7.7%, while average annual return on debt was only 4.4%. In the year of 2015 weight of equity capital, first time during the analyzed period, exceeded 50%. In the same year, ratio of net profit before taxes to total assets of Lithuanian manufacturing sector also reached the highest value at the time, later surpassed in 2016. This fact demonstrates, that increased free cash flows from the operations were reinvested into further development of the companies. To maximize value of the shareholders, it would be preferable to pay out portion of earnings as dividends and finance growth with debt, as it is currently a cheaper alternative.

One-Pot Multicomponent Reaction of Catechols, Ammonium Acetate, and Aldehydes for the Synthesis of Benzoxazole Derivatives Using the Fe(III)-Salen Complex.

The Fe(III)-salen complex has been applied successfully as a catalyst for the novel, simple, efficient, and one-pot multicomponent synthesis of benzoxazole derivatives from catechols, ammonium acetate as the nitrogen source, and aldehydes (nontoxic and cheap alternatives of amines) for the first time. Using this procedure, a wide range of benzoxazoles was successfully synthesized in the presence of a catalyst in EtOH under mild conditions, and all products were obtained in excellent yields. To the best of our knowledge, this method is the first example of the multicomponent synthesis of benzoxazole derivatives using these starting materials. The notable features such as the use of air that is considered as a benign oxidant and EtOH as a green solvent, ease of product separation, readily available and inexpensive aldehydes, and mild conditions make our procedure more efficient and practical for organic synthesis. Moreover, the current protocol is successfully applied to synthesize desirable products on a large scale.

Synthesis and Characterization of Zeolite-Y from natural clay of Wadi Hagul, Egypt

Zeolites were synthesized ‎from alternative cheap raw material as ‎clay minerals which used as a common source for Al2O3 and SiO2 for ‎‎synthesis zeolite-Y. Synthetic zeolite-Y has many characteristics, high ‎purity and larger cavities that distinguish it from its counterparts. This study concerned with evaluation of the viability of producing low-silica zeolite through the process of hydrothermal‎‎ calcination (metakaolinization) of raw material (kaolin) from Wadi Hagul, Egypt at 800oC for 6 h. Metakaolinite was synthesized under hydrothermal treatment with ‎‎ 1.0 M NaOH solution without additional any catalysts as silica source at 90oC/2d under atmospheric pressure. Zeolite Na-Y of molar ratio of 2.23 was ‎‎achieved. The Cation Exchange Capacity (CEC) test showed an impressive value of 401.09 meq/ 100 g clay for prepared zeolite-Y. The raw kaolin, metakaolin and zeolite were characterized by XRF, XRD and SEM. The results confirmed that Zeolite was successfully produced from the raw material extracted from Wadi Hagul with an ideal percentage which approximately equal to 100% of the raw material used. ‏The synthetic ‎zeolite-y can be applied for remediation of ‎wastewater ‎and polluted soil. ‎

Improvement to quality of surface waters from rural communities: vegetable extracts as a sustainable and cheap alternative

The high degree of pollution and cost of water treatment in rural communities of developing countries have led to a constant search of alternative cheap, versatile and easy for surface water treatment. In this sense, the aim of this study was to determine the removal power of turbidity, color, chlorides and nitrites of the plant pitahaya (Hylocereus triangularis), guasimo (Guazuma ulmifolia) and cactus nopal (Opuntia ficus-indica) in surface waters. An extraction was performed, and the optimal dose of each extract using a jar test was selected. After extracts were mixed to increase their flocculent/coagulant power, pitahaya removed turbidity in 97%, color 91%, chlorides 82% and nitrites 92%. For the same parameters, guasimo showed a removal of 95%, 89%, 74% and 94%, respectively. The mixture of pitahaya and guasimo removed 100% of nitrites. The plants studied have potential use for the removal of turbidity, color, chlorides and nitrites in water for human consumption and industrial wastewater.

Simulation study of the effects of phase separation on hydroxide solvation and transport in anion exchange membranes.

Anion exchange membranes (AEMs) can be cheaper alternatives than proton exchange membranes, but a key challenge for AEMs is to archive good ionic conductivity while maintaining mechanical strength. Diblock copolymers containing a mechanically strong hydrophobic block and an ion-conducting hydrophilic block have been shown to be viable solutions to this challenge. Using our recently developed reactive hydroxide model, we investigate the effects of block size on the hydroxide solvation and transport in a diblock copolymer (PPO-b-PVBTMA) in its highly hydrated state. Typically, both hydroxide and water diffusion constants decrease as the hydrophobic PPO block size increases. However, phase separation takes place above a certain mole ratio of hydrophobic PPO to hydrophilic PVBTMA blocks and we found it to effectively recover the diffusion constants. Extensive analyses reveal that morphological changes modulate the local environment for hydroxide and water transport and contribute to that recovery. The activation energy barriers for hydroxide and water diffusion show abrupt jumps at the same block ratios when such recovery effects begin to appear, suggesting transformation of the structure of water channels. Taking the advantages of partial phase separation can help optimize both ionic conductivity and mechanical strength of fuel cell membranes.

The effect of stone column area replacement ratio on seismic behaviour of foundation

Tall buildings require additional foundation solutions in order to resist the applied actions on soft soil sites. Nowadays the piled foundations are often altered by stone column solutions, as a cheap alternative. Structures built on soft soil or stiff soil, generally results in different behavior under earthquakes. However, the earthquake behavior of the stone column solution on different types of soil is still unclear. This paper aims to investigate the influence of different characteristics of soil structure interaction on the seismic response of stone column matt foundation. A reinforced concrete matt foundation was simulated with parametric soil stiffness and area replacement ratio of stone column. An analytical method was used to model the soil profile and appropriate ground motion data were incorporated for the analyses. The comparative results were presented and highlighted in terms of soil amplification and seismic response.

Plant species colonization in newly created road habitats of South Korea: Insights for more effective restoration

Despite the advances in restoration methods for newly created road habitats such as roadcuts and embankments, implementation in different parts of the world is limited by high cost and lack of knowledge of naturally formed plant communities. However, a cheaper alternative is to relay in natural successional process in sites under optimal conditions. Thus, the first steps should focus on identifying plant species that colonize roadways and road habitats as well as optimal colonization sites. Our study aimed to describe species composition, exotic species presence, and diversity among four roadways (Jeongok-Youngjung, JG; Seolma-Gueup, SM; Singal, SG; and Samga-Daechon, DC) and three habitat types (embankments, plain areas, and roadcuts) in South Korean peninsula. The effect of some environmental factors on plant composition was also examined (soil type, soil slope, and surrounding landscape). Our results showed that established plant species composition was influenced by the interaction between roadways and habitats types, which was also the main interaction affecting plant richness and evenness. Surprisingly, environmental variables had no effect on plant species composition, with a residual amount of explained variation. A total of 48 plant species were described as indicator of different roadways and habitat types, and 50% of them were invasive or cultivated species. It appeared that different regional-dependent processes, such as northern vs. southern roadways, interact with local process in new-road habitats, producing complex patterns of plant species colonization and composition. Thus, ecological restoration solutions should be targeted at site-specific needs (local) while taking into consideration the differences between northern and southern roadways (regional). Here, regional-pool and local-constraints interaction controls plant composition and diversity during road construction in South Korea. Finally, new restoration actions should be based on plant species that have been established spontaneously in these degraded areas.

Abstract P4-02-18: Sentinel node biopsy mapping using fluoresceine in breast cancer. An alternative for low and middle income countries

Abstract Background: All methods available for SNB identification suffer from many flaws including cost of the probes, allergies or management of radioactive material. Breast cancer is a challenging issue in LMIC [1]. Fluorescein has been described first in this meeting [2-3] as an alternative cheap and safe tracer in SNB mapping [4]. Our aim was to reproduce the feasibility and the safety of fluorescein SNB mapping compared with Isosulfan blue dye as a reference. Methods: Ten patients, with biopsy proven BC, were operated on for SNB biopsy and prospectively included over a period of one year (April 2018 - April 2019). Patients had 2 cc Isosulfan blue dye and 2 cc 10% fluorescein mixed with 4 cc of 9% saline solution injected subcutaneously in the peri-areolar area prior to lymph node biopsy. Fluorescent lymph nodes were detected by 5 nm ultra-violet light-emitting diode flashlight. They were removed and then remaining blue and/or suspicious nodes were removed. The detection rate and the complications were the primary objectives in this study. Results: Mean age was 40 years old (range 27 - 72). Mean size of the tumor was 20 mm (5 - 70mm). All patients but one had invasive breast carcinoma and one had ductal carcinoma in situ. All patients had no clinical or radiological suspicious nodal involvement before surgery. Six patients had a breast conserving surgery and four had a mastectomy. After a mean delay of 15,5 minutes after injection, SLN sampling was performed. All patients had fluorescent and blue nodes. A total of 27 fluorescent nodes and 25 blue nodes were harvested during these procedures. All blue nodes were fluorescent. Two nodes had micro-metastasis on final pathology. One of them was only detected by fluorescein. Adverse effects were represented by 2 seromas. No patient experienced an allergic reaction. Conclusion: In this pilot study, we were able to reproduce the published data where fluorescein based SNB detection was feasible, efficient in the detection rate and safe. We emphasize the need for a larger multicenter study to confirm the clinical utility of this tracer. The low cost of this technique will greatly help the development of SNB in LMIC Refernces: 1. Bellanger M, Zeinomar N, Tehranifar P, Terry MB. Are Global Breast Cancer Incidence and Mortality Patterns Related to Country-Specific Economic Development and Prevention Strategies? JGO. 8 juin 2018;(4):1-16. 2. Srivastava A, Suresh J, Ranjan P, et al: Fluorescent fluorescein with methylene blue compared to radioactive sulphur colloid with methylene blue: a randomised comparison. Proc SABCS 2017; abstr PD2-03. 3. Srivastava A, Kumar C,Kataria K fluorescence guided breast conserving surgery Proc SABCS 2018 PD 08 06 4. Chang YW, Lee HY, Lee CM, Jung SP, Kim WY, Woo SU, et al. Sentinel lymph node detection using fluorescein and blue light-emitting diodes in patients with breast carcinoma: A single-center prospective study. Asian Journal of Surgery [Internet]. 20 mars 2019. Citation Format: Remy Jacques Salmon, Mehdi Benna. Sentinel node biopsy mapping using fluoresceine in breast cancer. An alternative for low and middle income countries [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P4-02-18.

Isolation and Screening of Microbial Isolates from Kombucha Culture for Bacterial Cellulose Production in Sugarcane Molasses Medium

Kombucha tea is a traditional fermented beverage of Manchurian origins which is made of sugar and tea. The fermentation involves the application of a symbiotic consortium of bacteria and yeast (SCOBY) in which their metabolites provide health benefits for the consumer and subsequently allow the product to protect itself from contamination. Additionally, kombucha tea fermentation also produces a byproduct in the form of a pellicle composed of cellulose (Bacterial Cellulose, BC). Compared to plant cellulose, BC properties are more superior, which makes it industrially important. However, BC production at industrial scale has been faced with many challenges, including low yield and high fermentation medium cost. Many researchers have focused their studies on the use of alternative low cost media, such as molasses, which is a by-product of sugar refining process. To maximize the BC production in molasses medium, it is important to select the microbial strains that can grow and produce BC at high yield in molasses. This study aimed to isolate and characterize BC-producing bacteria and a dominant yeast from kombucha culture which had been previously adapted in molasses medium. The isolation of bacteria was performed using Nutrient Agar (NA) and Hestrin and Schramm (HS) supplemented with cycloheximide, while yeast was isolated using Potato Dextrose Agar (PDA) supplemented with chloramphenicol. The most dominant colonies were isolated and then subjected to microscopic observation for morphological analysis. The pure bacteria and yeast isolates were then identified by sequencing the 16S rRNA gene and D1/D2 region of the 26S rRNA, respectively. The bacteria isolates obtained were all from closely related genera: Komagataeibacter sp. DS1MA.62A, Komagataeibacter xylinus, Komagataeibacter saccharivorans, Komagataeibacter xylinus and Gluconacetobacter saccharivorans. The single isolated yeast was identified as Brettanomyces bruxellensis. This study helps to elucidate the BC-producing species which thrive in molasses medium for potential use in the BC production using molasses as alternative cheap carbon source. Also, the study revealed that the co-culture of Komagataeibacter sp. DS1MA.62A and B. bruxellensis could produce BC from molasses supplemented with caffeine and acetate buffer at an average yield of 27.7±1.83 g/L.
 Keywords: Kombucha, SCOBY, bacterial cellulose, Acetobacter, Komagataeibacter, Brettanomyces, alternative medium, molasses, caffeine, acetate buffer.

Skimmed milk as an alternative for IPTG in induction of recombinant protein expression

Cost-effectiveness is an important issue in biotechnological manufacturing industry and using alternative cheap materials with the same benefits has been noticed in most literatures. Isopropyl β-d-1-thiogalactopyranoside (IPTG), a well-known chemical element for induction of protein expression, has several disadvantages such as high expense and toxicity. In this study, we aimed to introduce skimmed milk as an alternative material for protein expression by induction of lac operon. In this way, Escherichia coli BL21 (DE3) bacteria were induced using 1 mM IPTG or 1.0% (w/v) skimmed milk. Protein purification was performed using Ni-NTA (nickel-nitrilotriacetic acid) for His-tagged recombinant proteins and protein purity was evaluated by SDS-PAGE. Results showed high level of recombinant protein expression using skimmed milk, and interestingly, the growth rate of bacteria improved. Our findings suggested that skimmed milk can be a suitable alternative for induction of recombinant protein expression, which has advantages such as more availability and affordability, in comparison to IPTG supplementation.

Semi-rational Design of Target-binding Small Proteins for Cancer Treatment

Small proteins that have a high affinity for cancer cell surface markers can be promising cheap alternatives to antibodies (antibody mimetics). Various types of antibody mimetics have thus been extensively developed. We recently found that a target-binding peptide binds to its target molecule more strongly when it is structurally constrained. To apply this finding to the development of chemically synthesizable small antibody mimetics, we have established an efficient method of creating such proteins, named fluctuation-regulated affinity proteins (FLAPs). To identify desirable scaffolds, first, 13 human proteins (46-104 aa) were selected from the Protein Data Bank. Then, thirteen graft acceptor (GA) sites that efficiently immobilize the grafted peptide structure were identified from six small protein scaffolds using molecular dynamics simulation. To assess the designed antibody mimetics in vitro, human epidermal growth factor receptor 2 (HER2)-binding peptides were selected from the anti-HER2 antibody drugs trastuzumab and pertuzumab by calculating the binding energy, and these were then grafted into the GA sites of scaffolds to create 65 FLAP candidates. The FLAP candidates were expressed in bacteria as fusion proteins with Renilla luciferase (Rluc), and their relative binding affinity to HER2 was easily determined by measuring the Rluc bioluminescence intensity without protein purification. Finally, four out of the 65 showed specific binding to HER2 with a dissociation constant (KD) of 24-65 nM, and these were used for the detection of HER2-expressing cancer cells. Our design strategy will promote the development of antibody mimetics for the effective treatment of cancers and other diseases.

Adding more "spice" to the pot: A review of the chemistry and pharmacology of newly emerging heterocyclic synthetic cannabinoid receptor agonists.

Synthetic cannabinoid receptor agonists (SCRAs) first appeared on the international recreational drug market in the early 2000s in the form of SCRA-containing herbal blends. Due to the cannabimimetic effects associated with the consumption of SCRAs, they have acquired an ill-informed reputation for being cheap, safe, and legal alternatives to illicit cannabis. Possessing high potency and affinity for the human cannabinoid receptor subtype-1 (CB1 ) and -2 (CB2 ), it is now understood that the recreational use of SCRAs can have severe adverse health consequences. The major public health problem arising from SCRA use has pressed legislators around the world to employ various control strategies to curb their recreational use. To circumvent legislative control measures, SCRA manufacturers have created a wide range of SCRA analogs that contain, more recently, previously unencountered azaindole, γ-carbolinone, or carbazole heterocyclic scaffolds. At present, little information is available regarding the chemical syntheses of these newly emerging classes of SCRA, from a clandestine perspective. When compared with previous generations of indole- and indazole-type SCRAs, current research suggests that many of these heterocyclic SCRA analogs maintain high affinity and efficacy at both CB1 and CB2 but largely evade legislative control. This review highlights the importance of continued research in the field of SCRA chemistry and pharmacology, as recreational SCRA use remains a global public health issue and represents a serious control challenge for law enforcement agencies.

Stochastic rounding and reduced-precision fixed-point arithmetic for solving neural ordinary differential equations.

Although double-precision floating-point arithmetic currently dominates high-performance computing, there is increasing interest in smaller and simpler arithmetic types. The main reasons are potential improvements in energy efficiency and memory footprint and bandwidth. However, simply switching to lower-precision types typically results in increased numerical errors. We investigate approaches to improving the accuracy of reduced-precision fixed-point arithmetic types, using examples in an important domain for numerical computation in neuroscience: the solution of ordinary differential equations (ODEs). The Izhikevich neuron model is used to demonstrate that rounding has an important role in producing accurate spike timings from explicit ODE solution algorithms. In particular, fixed-point arithmetic with stochastic rounding consistently results in smaller errors compared to single-precision floating-point and fixed-point arithmetic with round-to-nearest across a range of neuron behaviours and ODE solvers. A computationally much cheaper alternative is also investigated, inspired by the concept of dither that is a widely understood mechanism for providing resolution below the least significant bit in digital signal processing. These results will have implications for the solution of ODEs in other subject areas, and should also be directly relevant to the huge range of practical problems that are represented by partial differential equations.This article is part of a discussion meeting issue ‘Numerical algorithms for high-performance computational science’.