Synthesis and spectroscopy of upconverting lanthanide-doped nanocrystals

In the past two decades it has been widely demonstrated that the optical properties of select inorganic materials may be modified by changing either their size or shape on the nanometer level (sub-nanometer to 100 nm length scale). Much of the early research on this topic focused on semiconducting nanocrystals, where it has been effectively demonstrated that reducing particle size below their Bohr radius produced a characteristic blue shift of the band gap absorption. A little over a decade after the initial work on semiconducting nanocrystals, the first scientific articles on insulating nanocrystals doped with lanthanide ions started to appear. While numerous studies have focused on examining the luminescence generated by exciting with ultraviolet (UV) light, very few have examined the upconversion phenomenon in nanocrystalline materials. Upconversion is the generation of higher energy light from lower energy radiation typically through the use of lanthanide ions doped into a solid state host. Much of the interest in upconverting nanocrystalline materials is due to their prospective application as fluorescent biological labels. In this thesis the synthesis, spectroscopic, and upconversion properties of lanthanide-doped nanocrystalline materials will be discussed. We report on our efforts to date to achieve viable upconversion luminescence from Ho 3+ doped nanocrystalline Y 2 O 3 and Gd 3 Ga 5 O 12 prepared via the combustion synthesis. These studies have determined that, while upconversion occurs in Y 2 O 3 bulk samples, it is severely reduced or nonexistent in the nanocrystal samples. This behaviour is attributed to the presence of high vibrational energies, 1500 and 3350 cm -1 , due to adsorbed atmospheric CO 3 2- and OH - anions, respectively, on the surface of the nanocrystals. A substantial increase in the upconversion efficiencies was observed in the case of the garnet (Gd 3 Ga 5 O 12 ) nanocrystals due to considerably less surface contamination. The effect of Yb 3+ Co-doping on the upconversion luminescence in the Gd 3 Ga 5 O 12 sample will also be introduced. We also evaluate the spectroscopic properties of lutetium oxide nanocrystals doped with trivalent europium (Lu 2 O 3 :Eu 3+ ) prepared by the same combustion synthesis technique. These results are compared and contrasted to those of a bulk Lu 2 O 3 :Eu 3+ sample. In the case of Lu 2 O 3 we observe significant changes in the luminescence behaviour that we attribute to the vastly different particle sizes of the two different materials. Finally, we present a new procedure for synthesizing NaYF 4 :Er 3+ , Yb 3+ nanoparticles that are capable of colloidal dispersion in non-polar organic solvents. The highly luminescent nanoparticles are synthesized via the thermal decomposition of trifluoroacetate precusors in a mixture of oleic acid and octadecene. The Er 3+ , Yb 3+ and Tm 3+ , Yb 3+ doped cubic NaYF 4 nanocrystals exhibit green/red and blue upconversion luminescence, respectively under 980 nm laser excitation with low power densities while colloidally dispersed. A brief discussion on our current attempts and future efforts towards modifying the nanoparticles surface will also be given

Economics of Pre-Plant, Topdress, and Variable Rate Nitrogen Application in Winter Wheat

Past research about the efficiency of nitrogen application in winter wheat (Triticum aestivum L.) based on source and timing has produced inconsistent results. The majority of the literature used data from few locations over short time periods. This study used a unique data set of yields and nitrogen quantities from 2002-2009 at ten different locations in Oklahoma, USA. The objective of this research was to determine wheat yield response for granular pre-plant, uniform foliar topdress, and variable rate foliar topdress. Topdress liquid nitrogen had a 19% higher NUE than pre-plant urea, and was the most profitable source of nitrogen.linear stochastic plateau, nitrogen use efficiency, profitability, wheat, Crop Production/Industries,

Identifying Tennessee school-based agricultural education student growth and program accountability metrics

Over the years, accountability in education has transformed from the primary focus being the school as a whole to the individual teacher. The purpose of this study was to determine the metrics Tennessee school-based agricultural education teachers perceive as indicators of excellent total programs (classroom instruction, FFA, SAE), and a modified Delphi study was used to seek a consensus. The following nine metrics were retained: (a) pesticide certification, (b) program of activities, (c) number of students participating in CDEs, (d) chapter community service hours, (e) total number of FFA activities, (f) number of CDEs coached, (g) at least one proficiency at regional level, (h) one American degree every 3 years, and (i) percentage of students with SAE. Overall, the metrics agreed upon are narrow in focus and all but one is a record of activity and not direct measures of students’ knowledge or skills. As a result, the measures do not include student growth or value-added scores or authentic assessments of 21st century skills. Additional research is needed to further investigate the metrics that should be used to measure a school-based agricultural education program’s success in Tennessee and across the nation

The Application of Geographic Information Systems (GIS) to Improving Health Systems in the Upper East Region of Ghana

Despite the increased use of Geographic Information System (GIS) for health research, the technology is least used in settings where evidence based decision-making is needed most: High mortality settings of Africa where resource constraints impede the provision of essential care. This paper reports on a case study of GIS application in the Upper East Region (UER), one of the poorest regions in Ghana. Methods: Ghana Health Service (GHS) workers were trained to use GPS handheld devices to gather waypoints (coordinates) of all health care facilities and amenities throughout the UER. The waypoints data were then exported to Excel spreadsheets and cleaned of all inconsistencies. The final data was imported into ArcMap 10.2.2 software for data manipulation, display, and analysis. Results: Preventive health issues portrayed by GIS visualization included a substandard access to potable water in one community and health facility deficiencies in the Binduri district. As examples of GIS morbidity surveillance, we map the temporal incidence of cholera in two districts, and evidence of a pattern in the seasonal outbreaks of cerebral spinal meningitis (CSM). Conclusion: Results attest to the feasibility of using GIS to clarify health issues in a severely health service deprived setting, enabling public health authorities to optimize system responses where mostly needed. GIS technology has enabled health officials in the region to visualize the geographic pattern of disease outbreaks in ways that permit the imposition of efficient containment strategies

The child survival impact of the Ghana Essential Health Interventions Program: A health systems strengthening plausibility trial in Northern Ghana

Background: The Ghana Health Service in collaboration with partner institutions implemented a five-year primary health systems strengthening program known as the Ghana Essential Health Intervention Program (GEHIP). GEHIP was a plausibility trial implemented in an impoverished region of northern Ghana around the World Health Organizations (WHO) six pillars combined with community engagement, leadership development and grassroots political support, the program organized a program of training and action focused on strategies for saving newborn lives and community-engaged emergency referral services. This paper analyzes the effect of the GEHIP program on child survival. Methods: Birth history data assembled from baseline and endline surveys are used to assess the hazard of child mortality in GEHIP treatment and comparison areas prior to and after the start of treatment. Difference-in-differences (DiD) methods are used to compare mortality change over time among children exposed to GEHIP relative to children in the comparison area over the same time period. Models test the hypothesis that a package of systems strengthening activities improved childhood survival. Models adjusted for the potentially confounding effects of baseline differentials, secular mortality trends, household characteristics such as relative wealth and parental educational attainment, and geographic accessibility of clinical care. Results: The GEHIP combination of health systems strengthening activities reduced neonatal mortality by approximately one half (HR = 0.52, 95% CI = 0.28,0.98, p = 0.045). There was a null incremental effect of GEHIP on mortality of post-neonate infants (from 1 to 12 months old) (HR = 0.72; 95% CI = 0.30,1.79; p = 0.480) and post-infants (from 1 year to 5 years old) -(HR = 1.02; 95% CI = 0.55–1.90; p = 0.940). Age-specific analyses show that impact was concentrated among neonates. However, effect ratios for post-infancy were inefficiently assessed owing to extensive survival history censoring for the later months of childhood. Children were observed only rarely for periods over 40 months of age. Conclusion: GEHIP results show that a comprehensive approach to newborn care is feasible, if care is augmented by community-based nurses. It supports the assertion that if appropriate mechanisms are put in place to enable the various pillars of the health system as espoused by WHO in rural impoverished settings where childhood mortality is high, it could lead to accelerated reductions in mortality thereby increasing survival of children. Policy implications of the pronounced neonatal effect of GEHIP merit national review for possible scale-up

Patterns of care and outcomes for a clinical cohort of patients with lung cancer (2016-2021): Report on the Embedding Research (and Evidence) in Cancer Healthcare – EnRICH Program

Despite advances in diagnosis and treatment, lung cancer continues to be the leading cause of cancer-related death in Australia. Survival outcomes remain disappointing with less than a quarter of patients (22%) alive five years after diagnosis. Strategies to improve lung cancer care have focused on more rapid diagnosis and treatment from initial symptom presentation; a greater use of combined modalities of therapy; novel approaches using molecular-based diagnostics, targeted therapies, and immunotherapies; as well as a greater use of supportive and palliative care. The Embedding Research (and Evidence) in Cancer Healthcare (EnRICH) Program has explored patterns of care and clinical outcomes in a cohort of 2000 real-world patients presenting to six major specialist cancer centres in NSW with a first diagnosis between September 2016 and October 2021. This report provides valuable information on the natural history of patients following their initial diagnosis and maps out the use of evidence-based care, as well as identifying important factors defining overall prognosis. The report identifies that tumour stage at diagnosis remains one of the most important prognostic factors for both non-small cell (NSCLC) and small cell (SCLC) lung cancer. In NSCLC, stage, age, sex, performance status, co-morbid illness, neutrophil to lymphocyte ratio, haemoglobin levels, non-English speaking background, and mutation status are each independent factors predicting survival outcomes. Stage, performance status, and neutrophil to lymphocyte ratio are also predictive of survival in SCLC lung cancer. Overall, patients at major specialist cancer centres in NSW have done relatively well compared with other Australian cohorts such as those included in the Victorian Lung Cancer Registry and the Queensland Lung Cancer Quality Index, but it is important to note that the EnRICH cohort only includes those seen at least once at a major specialist cancer centre and does not represent all patients with lung cancer in these regions – a topic being further investigated in a subsequent report. Several quality indicators of cancer care are being captured and fed back to NSW practitioners and health administrators to inform practice and service development. While these indicators are comparable with other regions, there remain areas for improvement - a focus of ongoing work. Reassuringly, quality of care and outcomes for patients in the EnRICH cohort were not adversely affected by health service disruptions during the COVID-19 pandemic. Through this effort we hope to better document current outcomes of patients with lung cancer and the care they receive with the aim of improving current evidence-based care and accelerating the uptake of new emerging evidence

Author Correction: A consensus-based transparency checklist.

An amendment to this paper has been published and can be accessed via a link at the top of the paper

Evidence of the Generation of Isosaccharinic Acids and Their Subsequent Degradation by Local Microbial Consortia within Hyper-Alkaline Contaminated Soils, with Relevance to Intermediate Level Radioactive Waste Disposal

The contamination of surface environments with hydroxide rich wastes leads to the formation of high pH (>11.0) soil profiles. One such site is a legacy lime works at Harpur Hill, Derbyshire where soil profile indicated in-situ pH values up to pH 12. Soil and porewater profiles around the site indicated clear evidence of the presence of the α and β stereoisomers of isosaccharinic acid (ISA) resulting from the anoxic, alkaline degradation of cellulosic material. ISAs are of particular interest with regards to the disposal of cellulosic materials contained within the intermediate level waste (ILW) inventory of the United Kingdom, where they may influence radionuclide mobility via complexation events occurring within a geological disposal facility (GDF) concept. The mixing of uncontaminated soils with the alkaline leachate of the site resulted in ISA generation, where the rate of generation in-situ is likely to be dependent upon the prevailing temperature of the soil. Microbial consortia present in the uncontaminated soil were capable of surviving conditions imposed by the alkaline leachate and demonstrated the ability to utilise ISAs as a carbon source. Leachate-contaminated soil was sub-cultured in a cellulose degradation product driven microcosm operating at pH 11, the consortia present were capable of the degradation of ISAs and the generation of methane from the resultant H2/CO2 produced from fermentation processes. Following microbial community analysis, fermentation processes appear to be predominated by Clostridia from the genus Alkaliphilus sp, with methanogenesis being attributed to Methanobacterium and Methanomassiliicoccus sp. The study is the first to identify the generation of ISA within an anthropogenic environment and advocates the notion that microbial activity within an ILW-GDF is likely to influence the impact of ISAs upon radionuclide migration

Metastable Pluripotent States in NOD Mouse Derived ES Cells

Embryonic stem (ES) cells are isolated from the inner cell mass (ICM) of blastocysts, whereas epiblast stem cells (EpiSCs) are derived from the post-implantation epiblast and display a restricted developmental potential. Here we characterize pluripotent states in the non-obese diabetic (NOD) mouse strain, which prior to this study was considered “non-permissive” for ES cell derivation. We find that NOD stem cells can be stabilized by providing constitutive expression of Klf4 or c-Myc or small molecules that can replace these factors during in vitro reprogramming. The NOD ES and iPS cells appear “metastable”, as they acquire an alternative EpiSC-like identity after removal of the exogenous factors, while their reintroduction converts the cells back to ICM-like pluripotency. Our findings suggest that stem cells from different genetic backgrounds can assume distinct states of pluripotency in vitro, the stability of which is regulated by endogenous genetic determinants and can be modified by exogenous factors.National Institutes of Health (U.S.) (Grant RO1-HDO45022)National Institutes of Health (U.S.) (Grant R37-CA084198)National Institutes of Health (U.S.) (Grant RO1-CA087869

First Sample of Hα\alpha+[O III] λ\lambda5007 Line Emitters at z>6z > 6 through JWST/NIRCam Slitless Spectroscopy: Physical Properties and Line Luminosity Functions

We present a sample of four emission-line galaxies at $z=6.11-6.35$ that were serendipitously discovered using the commissioning data for the JWST/NIRCam wide-field slitless spectroscopy (WFSS) mode. One of them (at $z=6.11$) has been reported previously while the others are new discoveries. These sources are selected by the secure detections of both [O III] $\lambda$5007 and H$\alpha$ lines with other fainter lines tentatively detected in some cases (e.g., [O II] $\lambda$3727, [O III] $\lambda$4959 and [N II] $\lambda$6583). In the [O III]/H$\beta$ - [N II]/H$\alpha$ Baldwin-Phillips-Terlevich diagram, these galaxies occupy the same parameter space as that of $z\sim2$ star-forming galaxies, indicating that they have been enriched rapidly to sub-solar metallicities ($\sim$0.6 $Z_{\odot}$), similar to galaxies with comparable stellar masses at much lower redshifts. The detection of strong H$\alpha$ lines suggests a higher ionizing photon production efficiency within galaxies in the early Universe. We find brightening of the [O III] $\lambda$5007 line luminosity function (LF) from $z=3$ to 6, and no or weak redshift evolution of the H$\alpha$ line LF from $z=2$ to 6. Both LFs are under-predicted at $z\sim6$ by a factor of $\sim$10 in certain cosmological simulations. This further indicates a global Ly$\alpha$ photon escape fraction of 5-7% at $z\sim6$, much lower than previous estimates through the comparison of the UV-derived star-formation rate density and Ly$\alpha$ luminosity density. Our sample recovers $88^{+164}_{-57}$% of $z=6.0-6.6$ galaxies in the survey volume with stellar masses greater than $5\times10^8$ $M_{\odot}$, suggesting the ubiquity of strong H$\alpha$ and [O III] line emitters in the Epoch of Reionization, which will be further uncovered in the era of JWST.Comment: 25 pages, 11 figures, submitted to Ap