Nanotechnology for catalysis and solar energy conversion.

This roadmap on Nanotechnology for Catalysis and Solar Energy Conversion focuses on the application of nanotechnology in addressing the current challenges of energy conversion: 'high efficiency, stability, safety, and the potential for low-cost/scalable manufacturing' to quote from the contributed article by Nathan Lewis. This roadmap focuses on solar-to-fuel conversion, solar water splitting, solar photovoltaics and bio-catalysis. It includes dye-sensitized solar cells (DSSCs), perovskite solar cells, and organic photovoltaics. Smart engineering of colloidal quantum materials and nanostructured electrodes will improve solar-to-fuel conversion efficiency, as described in the articles by Waiskopf and Banin and Meyer. Semiconductor nanoparticles will also improve solar energy conversion efficiency, as discussed by Boschloo et al in their article on DSSCs. Perovskite solar cells have advanced rapidly in recent years, including new ideas on 2D and 3D hybrid halide perovskites, as described by Spanopoulos et al 'Next generation' solar cells using multiple exciton generation (MEG) from hot carriers, described in the article by Nozik and Beard, could lead to remarkable improvement in photovoltaic efficiency by using quantization effects in semiconductor nanostructures (quantum dots, wires or wells). These challenges will not be met without simultaneous improvement in nanoscale characterization methods. Terahertz spectroscopy, discussed in the article by Milot et al is one example of a method that is overcoming the difficulties associated with nanoscale materials characterization by avoiding electrical contacts to nanoparticles, allowing characterization during device operation, and enabling characterization of a single nanoparticle. Besides experimental advances, computational science is also meeting the challenges of nanomaterials synthesis. The article by Kohlstedt and Schatz discusses the computational frameworks being used to predict structure-property relationships in materials and devices, including machine learning methods, with an emphasis on organic photovoltaics. The contribution by Megarity and Armstrong presents the 'electrochemical leaf' for improvements in electrochemistry and beyond. In addition, biohybrid approaches can take advantage of efficient and specific enzyme catalysts. These articles present the nanoscience and technology at the forefront of renewable energy development that will have significant benefits to society.

How do climate change experiments alter plot-scale climate?

To understand and forecast biological responses to climate change, scientists frequently use field experiments that alter temperature and precipitation. Climate manipulations can manifest in complex ways, however, challenging interpretations of biological responses. We reviewed publications to compile a database of daily plot-scale climate data from 15 active-warming experiments. We find that the common practices of analysing treatments as mean or categorical changes (e.g. warmed vs. unwarmed) masks important variation in treatment effects over space and time. Our synthesis showed that measured mean warming, in plots with the same target warming within a study, differed by up to 1.6  ∘ C (63% of target), on average, across six studies with blocked designs. Variation was high across sites and designs: for example, plots differed by 1.1  ∘ C (47% of target) on average, for infrared studies with feedback control (n = 3) vs. by 2.2  ∘ C (80% of target) on average for infrared with constant wattage designs (n = 2). Warming treatments produce non-temperature effects as well, such as soil drying. The combination of these direct and indirect effects is complex and can have important biological consequences. With a case study of plant phenology across five experiments in our database, we show how accounting for drier soils with warming tripled the estimated sensitivity of budburst to temperature. We provide recommendations for future analyses, experimental design, and data sharing to improve our mechanistic understanding from climate change experiments, and thus their utility to accurately forecast species' responses.

Sleep dysfunction following neonatal ischemic seizures are differential by neonatal age of insult as determined by qEEG in a mouse model.

Neonatal seizures associated with hypoxic-ischemic encephalopathy (HIE) pose a challenge in their acute clinical management and are often followed by long-term neurological consequences. We used a newly characterized CD-1 mouse model of neonatal ischemic seizures associated with age-dependent (P7 vs. P10) seizure severity and phenobarbital efficacy (i.e.; PB-resistant vs. PB-efficacious respectively) following unilateral carotid ligation. The long-term consequences following untreated neonatal seizures in P7 vs. P10 ligated pups were investigated using neurobehavioral testing, 24 h v- quantitative EEG -EMG (qEEG, qEMG), and western blot analyses in adult mice. Significant hyperactivity emerged in a small sub-set of mice in both age-groups associated with a failure to habituate during open-field (OF) testing. 24 h continuous qEEGs detected significantly altered sleep architecture due to long-wake cycles in both age-groups. Delta power (0.5-4 Hz) quantification during slow-wave-sleep (SWS) revealed significant SWS compensation in P10 ligates following periods of increased sleep pressure which the P7 ligate group failed to show. Theta/beta ratios deemed as negative correlation markers of attentional control were significantly higher only in the P10 ligates. These results indicate that neonatal age-dependent differences in the characteristics of ischemic neonatal seizures in CD-1 pups differentially modulate long-term outcomes, when evaluated with v-qEEG/EMG as adults.

Diatoms response to salinity changes: investigations using single pulse and cross polarisation magic angle spinning 29Si NMR spectra.

Diatoms Thalassiosira pseudonana and Chaetoceros muelleri (Bacillariophyceae) were cultured at three different salinities (26, 36 and 46 practical salinity units (PSU)) and their silica content examined using natural abundance 29Si magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. The samples were investigated using both single pulse (SP) and cross-polarisation (CP) MAS experiments. In addition, samples of T. pseudonana were examined using variable contact time CP MAS experiments allowing the dynamics (TSiH and T1rρH) of CP to be determined. Comparison of SP and CP results revealed a change to a less condensed silica state when diatoms were cultured at salinities away from optimal (36 PSU). Further, an increased amount of organic material (but not its composition) was determined to be present for such samples affecting CP experiments. The location of the organic material, on the diatom surface or within the frustule, was unable to be determined.

Photofragment Imaging, Spectroscopy, and Theory of MnO.

Density functional and ab initio calculations, along with photodissociation spectroscopy and ion imaging of MnO+ from 21,300 to 33,900 cm-1, are used to probe the photodissociation dynamics and bond strength of the manganese oxide cation (MnO+). These studies confirm the theoretical ground state (5Π) and determine the spin-orbit constant ( A' = 14 cm-1) of the dominant optically accessible excited state (5Π) in the region. Photodissociation via this excited 5Π state results in ground state Mn+ (7S) + O (3P) products. At energies above 30,000 cm-1, the Mn+ (5S) + O (3P) channel is energetically accessible and becomes the preferred dissociation pathway. The bond dissociation energy ( D0 = 242 ± 5 kJ/mol) of MnO+ is measured from several images of each photofragmentation channel and compared to theory, resolving a disagreement in previous measurements. MRCI+Q calculations are much more successful in predicting the observed spectrum than TD-DFT or EOM-CCSD calculations.

Photofragment imaging and electronic spectroscopy of Al2.

A combination of photodissociation spectroscopy, ion imaging, and high-level theory is employed to refine the bond strength of the aluminum dimer cation (Al2+) and elucidate the electronic structure and photodissociation dynamics between 38 500 and 42 000 cm-1. Above 40 400 cm-1, structured photodissociation is observed from an extremely anharmonic excited state, which calculations identify as the double minimum G 2Σ+u state. The photodissociation spectrum of the G 2Σ+u ← X 2Σ+g transition in Al2+ gives an average vibrational spacing of 170 cm-1 for the G 2Σ+u state and ν0 = 172 cm-1 for the ground state. Photofragment images of G 2Σ+u ← X 2Σ+g transitions indicate that once the Al (4P) + Al+ (1S) product channel is energetically accessible, it dominates the lower energy, spin-allowed pathways despite being spin-forbidden. This is explained by a proposed competition between radiative and non-radiative decay pathways from the G 2Σ+u state. The photofragment images also yield D0 (Al+-Al) = 136.6 ± 1.8 kJ/mol, the most precise measurement to date, highlighting the improved resolution achieved from imaging at near-threshold energies. Additionally, combining D0 (Al+-Al) with IE (Al) and IE (Al2) gives an improved neutral D0 (Al-Al) = 136.9 ± 1.8 kJ/mol.

A systematic review of minimally invasive surgery for retrorectal tumors.

Retrorectal tumors are rare tumors that require resection for symptoms, malignancy and potential malignant transformation. Traditional approaches have included laparotomy, perineal excision or a combination. Multiple minimally invasive techniques are available which have the potential to minimize morbidity and enhance recovery. We performed a systematic review of the literature to determine the feasibility and surgical outcomes of retrorectal tumors approached using minimally invasive surgical techniques. Publications in which adult patients (≥ 18 years) had a minimally invasive approach (laparoscopic or robotic) for resection of a primary retrorectal tumor were included. Data were collected on approach, preoperative investigation, size and sacral level of the tumor, operating time, length of stay, perioperative complications, margins and recurrence. Thirty-five articles which included a total of 82 patients met the inclusion criteria. The majority of patients were female (n = 65; 79.2%), with a mean age of 41.7 years (range 18-89 years). Seventy-three patients (89.0%) underwent laparoscopic or combined laparoscopic-perineal resection, and 9 (10.8%) had a robotic approach. The conversion rate was 5.5%. The overall 30-day morbidity rate was 15.7%, including 1 intraoperative rectal injury (1.2%). Ninety-five percent (n = 78) of the retrorectal tumors were benign. Median length of stay was 4 days for both laparoscopic and robotic groups, with ranges of 1-8 and 2-10 days, respectively. No tumor recurrence was noted during follow-up [median 28 months (range 5-71 months)]. A minimally invasive approach for the resection of retrorectal tumors is feasible in selected patients. Careful patient selection is necessary to avoid incomplete resection and higher morbidity than traditional approaches.

Safety and efficacy of endoscopic spray cryotherapy for esophageal cancer.

Although surgery is traditionally the standard of care for esophageal cancer, esophagectomy carries significant morbidity. Alternative endoscopic therapies are needed for patients who are not candidates for conventional treatment. The objective of this study is to assess the safety, efficacy, and tolerability of spray cryotherapy of esophageal adenocarcinoma. This study includes patients with esophageal adenocarcinoma who had failed or were not candidates for conventional therapy enrolled retrospectively and prospectively in an open-label registry and patients in a retrospective cohort from 11 academic and community practices. Endoscopic spray cryotherapy was performed until biopsy proven local tumor eradication or until treatment was halted due to progression of disease, patient withdrawal or comorbidities. Eighty-eight patients with esophageal adenocarcinoma (median age 76, 80.7% male, mean length 5.1 cm) underwent 359 treatments (mean 4.4 per patient). Tumor stages included 39 with T1a, 25 with T1b, 9 with unspecified T1, and 15 with T2. Eighty-six patients completed treatment with complete response of intraluminal disease in 55.8%, including complete response in 76.3% for T1a, 45.8% for T1b, 66.2% for all T1, and 6.7% for T2. Mean follow-up was 18.4 months. There were no deaths or perforations related to spray cryotherapy. Strictures developed in 12 of 88 patients (13.6%) but were present before spray cryotherapy in 3 of 12. This study suggests that endoscopic spray cryotherapy is a safe, well-tolerated, and effective treatment option for early esophageal adenocarcinoma.

pHAST (pH-Driven Aptamer Switch for Thrombin) Catch-and-Release of Target Protein.

A pH-driven DNA nanomachine based on the human α-thrombin binding aptamer was designed for the specific catch-and-release of human α-thrombin at neutral and acidic pH, respectively. In neutral conditions, the thrombin aptamer component of the nanomachine is exposed and exists in the G-quadruplex conformation required to bind to the target protein. At slightly acidic pH, the polyadenine tail of the nanomachine becomes partially protonated and A+(anti)•G(syn) mispairing results in a conformational change, causing the target protein to be released. Förster resonance energy transfer (FRET) was used to monitor conformational switching over multiple pH cycles. Electrophoretic mobility shift assay (EMSA) and fluorescence anisotropy were used to show pH dependent protein binding and release by the nanomachine. This approach could be applied generally to existing G-rich aptamers to develop novel biosensors, theranostics, and nanoswitches.

Tetra-porphyrin molecular tweezers: two binding sites linked via a polycyclic scaffold and rotating phenyl diimide core.

The synthesis of a tetra-porphyrin molecular tweezer with two binding sites is described. The bis-porphyrin binding sites are aligned by a polycyclic scaffold and linked via a freely rotating phenyl diimide core. Synthesis was achieved using a divergent approach employing a novel coupling method for linking two polycyclic units to construct the core, with a copper(ii)-mediated phenyl boronic acid coupling found to extend to our polycyclic imide derivative. We expect this chemistry to be a powerful tool in accessing functional polycyclic supramolecular architectures in applications where north/south reactivity and/or directional interactions between modules are important. Porphyrin receptor functionalisation was undertaken last, by a four-fold ACE coupling reaction on the tetra-epoxide derivative of the core.

[Better Reporting of Interventions: Template for Intervention Description and Replication (TIDieR) Checklist and Guide]. / Die TIDieR Checkliste und Anleitung - ein Instrument für eine verbesserte Interventionsbeschreibung und Replikation.

Without a complete published description of interventions, clinicians and patients cannot reliably implement interventions that are shown to be useful, and other researchers cannot replicate or build on research findings. The quality of description of interventions in publications, however, is remarkably poor. To improve the completeness of reporting, and ultimately the replicability, of interventions, an international group of experts and stakeholders developed the Template for Intervention Description and Replication (TIDieR) checklist and guide. The process involved a literature review for relevant checklists and research, a Delphi survey of an international panel of experts to guide item selection, and a face-to-face panel meeting. The resultant 12-item TIDieR checklist (brief name, why, what (materials), what (procedure), who intervened, how, where, when and how much, tailoring, modifications, how well (planned), how well (actually carried out)) is an extension of the CONSORT 2010 statement (item 5) and the SPIRIT 2013 statement (item 11). While the emphasis of the checklist is on trials, the guidance is intended to apply across all evaluative study designs. This paper presents the TIDieR checklist and guide, with a detailed explanation of each item, and examples of good reporting. The TIDieR checklist and guide should improve the reporting of interventions and make it easier for authors to structure the accounts of their interventions, reviewers and editors to assess the descriptions, and readers to use the information.

Acute TrkB inhibition rescues phenobarbital-resistant seizures in a mouse model of neonatal ischemia.

Neonatal seizures are commonly associated with hypoxic-ischemic encephalopathy. Phenobarbital (PB) resistance is common and poses a serious challenge in clinical management. Using a newly characterized neonatal mouse model of ischemic seizures, this study investigated a novel strategy for rescuing PB resistance. A small-molecule TrkB antagonist, ANA12, used to selectively and transiently block post-ischemic BDNF-TrkB signaling in vivo, determined whether rescuing TrkB-mediated post-ischemic degradation of the K(+)-Cl(-) co-transporter (KCC2) rescued PB-resistant seizures. The anti-seizure efficacy of ANA12 + PB was quantified by (i) electrographic seizure burden using acute continuous video-electroencephalograms and (ii) post-treatment expression levels of KCC2 and NKCC1 using Western blot analysis in postnatal day (P)7 and P10 CD1 pups with unilateral carotid ligation. ANA12 significantly rescued PB-resistant seizures at P7 and improved PB efficacy at P10. A single dose of ANA12 + PB prevented the post-ischemic degradation of KCC2 for up to 24 h. As anticipated, ANA12 by itself had no anti-seizure properties and was unable to prevent KCC2 degradation at 24 h without follow-on PB. This indicates that unsubdued seizures can independently lead to KCC2 degradation via non-TrkB-dependent pathways. This study, for the first time as a proof-of-concept, reports the potential therapeutic value of KCC2 modulation for the management of PB-resistant seizures in neonates. Future investigations are required to establish the mechanistic link between ANA12 and the prevention of KCC2 degradation.

Systematic review with meta-analysis of the impact of surgical fellowship training on patient outcomes.

BACKGROUND: The number of surgeons entering fellowship training before independent practice is increasing. This may have a negative impact on surgeons in training. The impact of fellowship training on patient outcomes is not yet known. This review aimed to investigate the impact of fellowship training in surgery on patient outcomes. METHODS: A systematic review of the literature was conducted to identify studies exploring the structural and surgeon-specific characteristics of fellowship training on patient outcomes. Data from these studies were extracted, synthesized and reported qualitatively, or quantitatively through meta-analysis. RESULTS: Twenty-three studies were included. The mortality rate for patients in centres with an affiliated fellowship programme was lower than that for centres without (odds ratio 0.86, 95 per cent c.i. 0.84 to 0.88), as was the rate of complications (odds ratio 0.90, 0.78 to 1.02). Surgeons without fellowship training converted more laparoscopic operations to open surgery than those with fellowship training (risk ratio (RR) 1.04, 95 per cent c.i. 1.03 to 1.05). Comparison of outcomes for senior surgeons versus current fellows showed no differences in rates of mortality (RR 1.00, 1.00 to 1.01), complications (RR 1.03, 0.98 to 1.08) or conversion to open surgery (RR 1.01, 1.00 to 1.01). CONCLUSION: Fellowship training appears to have a positive impact on patient outcomes.

Pollen limitation and its influence on natural selection through seed set.

Stronger pollen limitation should increase competition among plants, leading to stronger selection on traits important for pollen receipt. The few explicit tests of this hypothesis, however, have provided conflicting support. Using the arithmetic relationship between these two quantities, we show that increased pollen limitation will automatically result in stronger selection (all else equal) although other factors can alter selection independently of pollen limitation. We then tested the hypothesis using two approaches. First, we analysed the published studies containing information on both pollen limitation and selection. Second, we explored how natural selection measured in one Ontario population of Lobelia cardinalis over 3 years and two Michigan populations in 1 year relates to pollen limitation. For the Ontario population, we also explored whether pollinator-mediated selection is related to pollen limitation. Consistent with the hypothesis, we found an overall positive relationship between selection strength and pollen limitation both among species and within L. cardinalis. Unexpectedly, this relationship was found even for vegetative traits among species, and was not found in L. cardinalis for pollinator-mediated selection on nearly all trait types.

Postoperative recurrence of Crohn's disease: impact of endoscopic monitoring and treatment step-up.

AIM: Eighty per cent of patients with Crohn's disease require surgery, of whom 70% will require a further operation. Recurrence occurs at the anastomosis. Although often recommended, the impact of postoperative colonoscopy and treatment adjustment is unknown. METHOD: Patients with a bowel resection over a 10-year period were reviewed and comparison made between those who did and did not have a postoperative colonoscopy within 1 year of surgery, and those who did or did not have a step-up in drug therapy. RESULTS: Of 222 patients operated on, 136 (65 men, mean age 33 years, mean disease duration 8 years, median follow-up 4 years) were studied. Of 70 patients with and 66 without postoperative colonoscopy, clinical recurrence occurred in 49% and 48% (NS) and further surgery in 9% and 5% (NS). Eighty-nine per cent of colonoscoped patients had a decision based on the colonoscopic findings: of these, 24% had a step-up of drug therapy [antibiotics (n =10), aminosalicylates (n=2), thiopurine (n=5), methotrexate (n=1)] and 76% had no step-up in drug therapy. In colonoscoped patients clinical recurrence occurred in 9 (60%) of 15 patients with, and 23 (49%) of 47 without step-up and surgical recurrence in 2 (13%) of 15 and 4 (9%) of 47 (NS). CONCLUSION: Clinical recurrence occurs in a majority of patients soon after surgery. In this cohort, there was no clinical benefit from colonoscopy or increased drug therapy within 1 year after operation. However, the response to the endoscopic findings was not standardized and immunosuppressive therapy was uncommon. Standardizing timing of colonoscopy and drug therapy, including more intense therapy, may improve outcome, although this remains to be proven.

Establishing a Canadian registry of patients with amyotrophic lateral sclerosis.

BACKGROUND: Amyotrophic lateral sclerosis (ALS) is a devastating cause of progressive weakness, respiratory failure and death. To date there is no effective therapy to meaningfully extend survival but continuously emerging targets and putative treatments are studied in clinical trials. Canadian epidemiological data on ALS is scarce and the socioeconomic impact of ALS on Canadian society is unclear. The Canadian Neuromuscular Disease Registry (CNDR) is a national clinic-based registry of patients with neuromuscular diseases with the goal of facilitating the design and execution of clinical research. METHODS: We conducted a national stakeholder survey to assess interest for a Canadian ALS registry and an assessment of expected case ascertainment. A dataset derivation meeting was held to establish the registry medical dataset. RESULTS: We report the results of the national stakeholder survey, case ascertainment assessment, and the derived dataset that have resulted in the current implementation of a Canadian registry of patients with ALS. CONCLUSIONS: The development of this long sought-after resource is a significant step forward for the Canadian ALS patient and research communities that will result in more efficient clinical trial recruitment and advancements in our understanding of ALS in Canada.