Plastic production is an essential part of the world economy that has mushroomed exponentially with c.9.2 billion tonnes estimated to have been made between 1950 and 2017. Now, each year c.8–11 ...million tonnes of plastic waste escapes into the oceans. Plastic usage is varied but the packaging industry accounts for 47%. Recycling and the circular economy are seen as keys to unlocking the plastic problem, for example, via the Extended Producer Responsibility scheme; a Deposit Return Scheme. The circular economy is a fine idea and has been around a long time, but has it made any real difference? The amount of plastic in circulation keeps getting bigger and bigger. More thought must be given to creating technologies and designs that can deal with waste management, integrate international collaboration and cut waste to a bare minimum at its source point upstream. No single solution exists, but there is a need for a legally binding global governance arrangement that would effectively and measurably limit and control plastic pollution. Many governments are in favour of this.
•Plastic production has mushroomed exponentially.•Plastic litter has been documented in all coastal and marine environments.•A change in systematic thinking could give a sound start to resolve the plastic issue.•Plastic pollution will never be overcome without a unified and consistent approach.•The plastic value chain must be transformed towards a more sustainable world.
Display omitted
•Catalytic pyrolysis of waste plastics produces H2 and carbon nanotubes (CNTs).•Ni-Fe catalysts and different alumina supports have been investigated.•H2& CNTs production is highly ...dependent on catalyst type and process parameters.•Bimetallic Ni-Fe/γ-Al2O3 produced 31.8mmol H2/gplastic and 287mgg−1plastic CNTs.
The use of Ni-Fe catalysts for the catalytic pyrolysis of real-world waste plastics to produce hydrogen and high value carbon nanotubes (CNT), and the influence of catalyst composition and support materials has been investigated. Experiments were conducted in a two stage fixed bed reactor, where plastics were pyrolysed in the first stage followed by reaction of the evolved volatiles over the catalyst in the second stage. Different catalyst temperatures (700, 800, 900°C) and steam to plastic ratios (0, 0.3, 1, 2.6) were explored to optimize the product hydrogen and the yield of carbon nanotubes deposited on the catalyst. The results showed that the growth of carbon nanotubes and hydrogen were highly dependent on the catalyst type and the operational parameters. Fe/γ-Al2O3 produced the highest hydrogen yield (22.9mmol H2/gplastic) and carbon nanotubes yield (195mgg−1plastic) among the monometallic catalysts, followed by Fe/α-Al2O3, Ni/γ-Al2O3 and Ni/α-Al2O3. The bimetallic Ni-Fe catalyst showed higher catalytic activity in relation to H2 yield than the monometallic Ni or Fe catalysts because of the optimum interaction between metal and support. Further investigation of the influence of steam input and catalyst temperature on product yields found that the optimum simultaneous production of CNTs (287mgg−1plastic) and hydrogen production (31.8mmol H2/gplastic) were obtained at 800°C in the absence of steam and in the presence of the bimetallic Ni-Fe/γ-Al2O3 catalyst.
Maneuvering safely through the environment is central to survival of almost all species. The ability to do this depends on learning and remembering locations. This capacity is encoded in the brain by ...two systems: one using cues outside the organism (distal cues), allocentric navigation, and one using self-movement, internal cues and nearby proximal cues, egocentric navigation. Allocentric navigation involves the hippocampus, entorhinal cortex, and surrounding structures; in humans this system encodes allocentric, semantic, and episodic memory. This form of memory is assessed in laboratory animals in many ways, but the dominant form of assessment is the Morris water maze (MWM). Egocentric navigation involves the dorsal striatum and connected structures; in humans this system encodes routes and integrated paths and, when overlearned, becomes procedural memory. In this article, several allocentric assessment methods for rodents are reviewed and compared with the MWM. MWM advantages (little training required, no food deprivation, ease of testing, rapid and reliable learning, insensitivity to differences in body weight and appetite, absence of nonperformers, control methods for proximal cue learning, and performance effects) and disadvantages (concern about stress, perhaps not as sensitive for working memory) are discussed. Evidence-based design improvements and testing methods are reviewed for both rats and mice. Experimental factors that apply generally to spatial navigation and to MWM specifically are considered. It is concluded that, on balance, the MWM has more advantages than disadvantages and compares favorably with other allocentric navigation tasks.
GABA release from interneurons in VTA, projections from the nucleus accumbens (NAc), and rostromedial tegmental nucleus (RMTg) was selectively activated in rat brain slices. The inhibition induced by ...μ-opioid agonists was pathway dependent. Morphine induced a 46% inhibition of IPSCs evoked from the RMTg, 18% from NAc, and IPSCs evoked from VTA interneurons were almost insensitive (11% inhibition). In vivo morphine treatment resulted in tolerance to the inhibition of RMTg, but not local interneurons or NAc, inputs. One common sign of opioid withdrawal is an increase in adenosine-dependent inhibition. IPSCs evoked from the NAc were potently inhibited by activation of presynaptic adenosine receptors, whereas IPSCs evoked from RMTg were not changed. Blockade of adenosine receptors selectively increased IPSCs evoked from the NAc during morphine withdrawal. Thus, the acute action of opioids, the development of tolerance, and the expression of withdrawal are mediated by separate GABA afferents to dopamine neurons.
•GABA pathways to dopamine neurons are selectively sensitive to μ-opioid agonists•GABA pathways to dopamine neurons are selectively sensitive to adenosine agonists•Pathways that are most sensitive to opioids and adenosine are different•Morphine withdrawal is expressed selectively at terminals from nucleus accumbens
Matsui et al. studied three opioid-sensitive GABA inputs to VTA dopamine neurons. The balance between initial sensitivity, development of tolerance, and expression of withdrawal were different for each pathway. Thus, different neuronal pathways regulate the three stages of opioid action.
Lysergic acid diethylamide (LSD) is a potent serotonergic hallucinogen or psychedelic that modulates consciousness in a marked and novel way. This study sought to examine the acute and mid-term ...psychological effects of LSD in a controlled study.
A total of 20 healthy volunteers participated in this within-subjects study. Participants received LSD (75 µg, intravenously) on one occasion and placebo (saline, intravenously) on another, in a balanced order, with at least 2 weeks separating sessions. Acute subjective effects were measured using the Altered States of Consciousness questionnaire and the Psychotomimetic States Inventory (PSI). A measure of optimism (the Revised Life Orientation Test), the Revised NEO Personality Inventory, and the Peter's Delusions Inventory were issued at baseline and 2 weeks after each session.
LSD produced robust psychological effects; including heightened mood but also high scores on the PSI, an index of psychosis-like symptoms. Increased optimism and trait openness were observed 2 weeks after LSD (and not placebo) and there were no changes in delusional thinking.
The present findings reinforce the view that psychedelics elicit psychosis-like symptoms acutely yet improve psychological wellbeing in the mid to long term. It is proposed that acute alterations in mood are secondary to a more fundamental modulation in the quality of cognition, and that increased cognitive flexibility subsequent to serotonin 2A receptor (5-HT2AR) stimulation promotes emotional lability during intoxication and leaves a residue of 'loosened cognition' in the mid to long term that is conducive to improved psychological wellbeing.
Display omitted
•Two-stage pyrolysis-catalysis of waste plastics produced gasoline range hydrocarbons.•Catalysis was staged using MCM-41 then ZSM-5 was used.•High yields of oil (83.15wt.%) at 1:1 ...ratio was obtained with high aromatic content.•Pyrolysis-staged catalysis of several real-world waste plastics were also investigated.•Effective conversion of waste plastics to gasoline range hydrocarbons was achieved.
The two-stage pyrolysis-catalysis of high density polyethylene has been investigated with pyrolysis of the plastic in the first stage followed by catalysis of the evolved hydrocarbon pyrolysis gases in the second stage using solid acid catalysts to produce gasoline range hydrocarbon oil (C8–C12). The catalytic process involved staged catalysis, where a mesoporous catalyst was layered on top of a microporous catalyst with the aim of maximising the conversion of the waste plastic to gasoline range hydrocarbons. The catalysts used were mesoporous MCM-41 followed by microporous ZSM-5, and different MCM-41:zeolite ZSM-5 catalyst ratios were investigated. The MCM-41 and zeolite ZSM-5 were also used alone for comparison. The results showed that using the staged catalysis a high yield of oil product (83.15wt.%) was obtained from high density polyethylene at a MCM-41:ZSM-5 ratio of 1:1 in the staged pyrolysis-catalysis process. The main gases produced were C2 (mainly ethene), C3 (mainly propene), and C4 (mainly butene and butadiene) gases. In addition, the oil product was highly aromatic (95.85wt.% of oil) consisting of 97.72wt.% of gasoline range hydrocarbons.
In addition, pyrolysis-staged catalysis using a 1:1 ratio of MCM-41: zeolite ZSM-5 was investigated for the pyrolysis–catalysis of several real-world waste plastic samples from various industrial sectors. The real world samples were, agricultural waste plastics, building reconstruction plastics, mineral water container plastics and household food packaging waste plastics. The results showed that effective conversion of the real-world waste plastics could be achieved with significant concentrations of gasoline range hydrocarbons obtained.
"Quantile-dependent expressivity" occurs when the effect size of a genetic variant depends upon whether the phenotype (e.g., leptin) is high or low relative to its distribution. Leptin concentrations ...are strongly related to adiposity, whose heritability is quantile dependent. Whether inheritance of leptin concentrations is quantile dependent, and whether this explains the greater heritability in women than men in accordance with their greater adiposity, and explains other gene-environment interactions, remains to be determined. Therefore, leptin and leptin receptor concentrations from 3068 siblings in 1133 sibships from the Framingham Heart Study Third Generation Cohort were analyzed. Free leptin index (FLI) was calculated as the ratio of leptin to soluble leptin receptor concentrations. Full-sib (β
) regression slopes were robustly estimated by quantile regression with nonparametric significance assigned from 1000 bootstrap samples. The analyses showed β
increased significantly with increasing percentiles of the offspring's age- and sex-adjusted leptin distribution (P
= 0.0001), which was accelerated at the higher concentrations (P
= 0.0003). β
at the 90th percentile (0.418 ± 0.066) was 4.7-fold greater than at the 10th percentile (0.089 ± 0.032, P
= 3.6 × 10
). Consistent with quantile-dependent expressivity, the β
was greater in female sibs, which was attributable to their higher leptin concentrations. Reported gene-environment interactions involving adiposity and LEP, LEPR, MnSOD, PPARγ, PPARγ2, and IRS-1 polymorphisms were consistent with quantile-dependent expressivity of leptin concentrations. β
for leptin receptor concentrations and free leptin index also increased significantly with increasing percentiles of their distributions (P
= 0.04 and P
= 8.5 × 10
, respectively). In conclusion, inherited genetic and shared environmental effects on leptin concentrations were quantile dependent, which likely explains male-female differences in heritability and some gene-environment interactions.
Safety surveillance of vaccines against COVID-19 is critical to ensure safety, maintain trust, and inform policy.
To monitor 23 serious outcomes weekly, using comprehensive health records on a ...diverse population.
This study represents an interim analysis of safety surveillance data from Vaccine Safety Datalink. The 10 162 227 vaccine-eligible members of 8 participating US health plans were monitored with administrative data updated weekly and supplemented with medical record review for selected outcomes from December 14, 2020, through June 26, 2021.
Receipt of BNT162b2 (Pfizer-BioNTech) or mRNA-1273 (Moderna) COVID-19 vaccination, with a risk interval of 21 days for individuals after vaccine dose 1 or 2 compared with an interval of 22 to 42 days for similar individuals after vaccine dose 1 or 2.
Incidence of serious outcomes, including acute myocardial infarction, Bell palsy, cerebral venous sinus thrombosis, Guillain-Barré syndrome, myocarditis/pericarditis, pulmonary embolism, stroke, and thrombosis with thrombocytopenia syndrome. Incidence of events that occurred among vaccine recipients 1 to 21 days after either dose 1 or 2 of a messenger RNA (mRNA) vaccine was compared with that of vaccinated concurrent comparators who, on the same calendar day, had received their most recent dose 22 to 42 days earlier. Rate ratios (RRs) were estimated by Poisson regression, adjusted for age, sex, race and ethnicity, health plan, and calendar day. For a signal, a 1-sided P < .0048 was required to keep type I error below .05 during 2 years of weekly analyses. For 4 additional outcomes, including anaphylaxis, only descriptive analyses were conducted.
A total of 11 845 128 doses of mRNA vaccines (57% BNT162b2; 6 175 813 first doses and 5 669 315 second doses) were administered to 6.2 million individuals (mean age, 49 years; 54% female individuals). The incidence of events per 1 000 000 person-years during the risk vs comparison intervals for ischemic stroke was 1612 vs 1781 (RR, 0.97; 95% CI, 0.87-1.08); for appendicitis, 1179 vs 1345 (RR, 0.82; 95% CI, 0.73-0.93); and for acute myocardial infarction, 935 vs 1030 (RR, 1.02; 95% CI, 0.89-1.18). No vaccine-outcome association met the prespecified requirement for a signal. Incidence of confirmed anaphylaxis was 4.8 (95% CI, 3.2-6.9) per million doses of BNT162b2 and 5.1 (95% CI, 3.3-7.6) per million doses of mRNA-1273.
In interim analyses of surveillance of mRNA COVID-19 vaccines, incidence of selected serious outcomes was not significantly higher 1 to 21 days postvaccination compared with 22 to 42 days postvaccination. While CIs were wide for many outcomes, surveillance is ongoing.
Activated carbons were prepared by phosphoric acid activation of cotton stalks in a nitrogen atmosphere at various temperatures in the 500–800 °C range and at different H3PO4 acid to cotton stalk ...impregnation ratios (0.3–3). In addition pyrolysis was undertaken in a thermogravimetric analyser in the presence of different ratios of phosphoric acid in order to establish the nature of the biomass to carbon transformations involved. It was established that the total activation process of H3PO4-impregnated cotton stalks occurred in four stages with the main degradation at 740 °C, compared with 330 °C for raw cotton stalks. The effects of impregnation ratio and activation temperature on the yield and adsorption capacities of activated carbon were evaluated. The chemical composition of the carbons was investigated by elemental analysis and infrared spectroscopy. The impregnation ratio and activation temperature show a strong influence on the yields and the porous texture of the resultant activated carbons. It was demonstrated that increasing impregnation ratio favours the development of mesopores especially at high activation temperature. The activated carbons showed BET surface areas ranging from 330 to 1720 m2 g−1, total pore volumes of 0.15–1.23 cm3 g−1 with mesopore volumes between 0 and 0.61 cm3 g−1. Results suggest the practical feasibility of phosphoric acid activation of cotton stalks, which produces high quality activated carbons with high fractions of micropores and mesopores.
► High surface area (1720 m2 g−1) activated carbons have been produced. ► Process conditions can be altered to produce microporous or mesoporous carbons. ► Four stages of thermal degradation of the biomass have been identified. ► Phosphates interact with the biomass influencing pore formation.
PDF
