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Dental agenesis is one of the most common developmental anomalies in humans, characterised by the developmental absence of one or more teeth. It can present as an isolated condition (non-syndromic hypodontia) or associated with a syndrome (syndromic hypodontia). This paper aims to review the genetic basis of hypodontia with reference to aetiology, classification and the subsequent clinical features.

Current periodontal treatment involves instrumentation using hand and/or ultrasonic instruments, which are used either alone or in combination based on patient and clinician preference, with comparable clinical outcomes. This study sought to investigate early and later changes in the subgingival biofilm following periodontal treatment, to identify whether these changes were associated with treatment outcomes, and to investigate whether the biofilm responded differently to hand compared with ultrasonic instruments. This was a secondary‐outcome analysis of a randomized‐controlled trial. Thirty‐eight periodontitis patients received full‐mouth subgingival instrumentation using hand (n= 20) or ultrasonic instrumentation (n= 18). Subgingival plaque was sampled at baseline and 1, 7, and 90 days following treatment. Bacterial DNA was analyzed using 16S rRNA sequencing. Periodontal clinical parameters were evaluated before and after treatment. Biofilm composition was comparable in both (hand and ultrasonics) treatment groups at all time points (all genera and species; p[adjusted] > 0.05). Large‐scale changes were observed within groups across time points. At days 1 and 7, taxonomic diversity and dysbiosis were reduced, with an increase in health‐associated genera including Streptococcusand Rothiaequating to 30% to 40% of the relative abundance. When reassessed at day 90 a subset of samples reformed a microbiome more comparable with baseline, which was independent of instrumentation choice and residual disease. Hand and ultrasonic instruments induced comparable impacts on the subgingival plaque microbiome. There were marked early changes in the subgingival biofilm composition, although there was limited evidence that community shifts associated with treatment outcomes.

ObjectiveThis exploratory post hocanalysis sought to investigate clinical outcomes comparing non-surgical treatment for periodontal disease using exclusively hand instruments, exclusively ultrasonic instruments or a combination approach. Differences in time efficiency and equipment use with each treatment method were evaluated.

Phytoplankton blooms are a global water quality issue, and successful management depends on understanding their responses to multiple and interacting drivers, including nutrient loading and climate change. Here, we examine a long‐term dataset from Lake 227, a site subject to a fertilization experiment (1969–present) with changing nitrogen:phosphorus (N:P) ratios. We applied a process‐oriented model, MyLake, and updated the model structure with nutrient uptake kinetics that incorporated shifting N:P and competition among phytoplankton functional groups. We also tested different temperature and P‐loading scenarios to examine the interacting effects of climate change and nutrient loading on phytoplankton blooms. The model successfully reproduced lake physics over 48 yr and the timing, overall magnitude, and shifting community structure (diazotrophs vs. non‐diazotrophs) of phytoplankton blooms. Intra‐ and interannual variability was captured more accurately for the P‐only fertilization period than for the high N:P and low N:P fertilization periods, highlighting the difficulty of modeling complex blooms even in well‐studied systems. A model scenario was also run which removed climate‐driven temperature trends, allowing us to disentangle concurrent drivers of blooms. Results showed that increases in water temperature in the spring led to earlier and larger phytoplankton blooms under climate change than under the effects of nutrient fertilization alone. These findings suggest that successful lake management efforts should incorporate the effects of climate change in addition to nutrient reductions, including intensifying and/or expanding monitoring periods and incorporating climate change into uncertainty estimates around future conditions.

Anthropogenic releases of mercury (Hg)1–3are a human health issue4because the potent toxicant methylmercury (MeHg), formed primarily by microbial methylation of inorganic Hg in aquatic ecosystems, bioaccumulates to high concentrations in fish consumed by humans5,6. Predicting the efficacy of Hg pollution controls on fish MeHg concentrations is complex because many factors influence the production and bioaccumulation of MeHg7–9. Here we conducted a 15-year whole-ecosystem, single-factor experiment to determine the magnitude and timing of reductions in fish MeHg concentrations following reductions in Hg additions to a boreal lake and its watershed. During the seven-year addition phase, we applied enriched Hg isotopes to increase local Hg wet deposition rates fivefold. The Hg isotopes became increasingly incorporated into the food web as MeHg, predominantly from additions to the lake because most of those in the watershed remained there. Thereafter, isotopic additions were stopped, resulting in an approximately 100% reduction in Hg loading to the lake. The concentration of labelled MeHg quickly decreased by up to 91% in lower trophic level organisms, initiating rapid decreases of 38–76% of MeHg concentration in large-bodied fish populations in eight years. Although Hg loading from watersheds may not decline in step with lowering deposition rates, this experiment clearly demonstrates that any reduction in Hg loadings to lakes, whether from direct deposition or runoff, will have immediate benefits to fish consumers.

Objectives.We assessed the accuracy of case definition algorithms for psoriasis and psoriatic arthritis (PsA) in health administrative data and used primary care electronic medical records (EMR) to describe disease and treatment characteristics of these patients.Methods.We randomly sampled 30,424 adult Ontario residents from the Electronic Medical Record Primary Care database and identified 2215 patients with any possible psoriatic disease–related terms in their EMR. The relevant patient records were chart abstracted to confirm diagnoses of psoriasis or PsA. This validation set was then linked to health administrative data to assess the performance of different algorithms for physician billing diagnosis codes, hospitalization diagnosis codes, and medications for psoriatic disease. We report the performance of selected case definition algorithms and describe the disease characteristics of the validation set.Results.Our reference standard identified 1028 patients with psoriasis and 77 patients with PsA, for an overall prevalence of 3.4% for psoriasis and 0.3% for PsA. Most patients with PsA (66%) had a rheumatology-confirmed diagnosis, while only 30% of the patients with psoriasis had dermatology-confirmed diagnosis. The use of systemic medications was much more common with PsA than with psoriasis. All algorithms had excellent specificity (97–100%). The sensitivity and positive predictive value were moderate and varied between different algorithms (34–72%).Conclusion.The accuracy of case definition algorithms for psoriasis and PsA varies widely. However, selected algorithms produced population prevalence estimates that were within the expected ranges, suggesting that they may be useful for future research purposes.

Understanding microplastic exposure and effects is critical to understanding risk. Here, we used large, in-lake closed-bottom mesocosms to investigate exposure and effects on pelagic freshwater ecosystems. This article provides details about the experimental design and results on the transport of microplastics and exposure to pelagic organisms. Our experiment included three polymers of microplastics (PE, PS, and PET) ranging in density and size. Nominal concentrations ranged from 0 to 29,240 microplastics per liter on a log scale. Mesocosms enclosed natural microbial, phytoplankton, and zooplankton communities and yellow perch (Perca flavescens). We quantified and characterized microplastics in the water column and in components of the food web (biofilm on the walls, zooplankton, and fish). The microplastics in the water stratified vertically according to size and density. After 10 weeks, about 1% of the microplastics added were in the water column, 0.4% attached to biofilm on the walls, 0.01% within zooplankton, and 0.0001% in fish. Visual observations suggest the remaining >98% were in a surface slick and on the bottom. Our study suggests organisms that feed at the surface and in the benthos are likely most at risk, and demonstrates the value of measuring exposure and transport to inform experimental designs and achieve target concentrations in different matrices within toxicity tests.

To estimate the prevalence and incidence of psoriasis and psoriatic arthritis (PsA) over time in Ontario, Canada. We performed a population‐based study of Ontario health administrative data, using validated case definitions for psoriasis and PsA. We computed the crude and age‐ and sex‐standardized cumulative prevalence and incidence of psoriasis from 2000 to 2015. Among the 10,774,802 individuals ages ≥20 years residing in Ontario in 2015, we identified 273,238 patients with psoriasis and 18,655 patients with PsA, equating to cumulative prevalence estimates of 2.54% and 0.17%, respectively. Correcting the prevalence estimates for imperfect sensitivity and specificity resulted in similar estimates. The male:female ratio was approximately 1.0 for both conditions. For psoriasis, the age‐ and sex‐standardized cumulative prevalence increased from 1.74% in 2000 to 2.32% in 2015. For PsA, the age‐ and sex‐standardized cumulative prevalence increased from 0.09% in 2008 to 0.15% in 2015. Between 2008 and 2015, annual incidence rates for psoriasis decreased, whereas those for PsA remained relatively stable. The prevalence and incidence of psoriasis and PsA in Ontario are similar to those observed in Europe and the US. The steady increase in the prevalence of psoriasis and PsA over the past decade may be due to a combination of population aging, population growth, and increasing life expectancy.

Dissolved organic carbon (DOC) was measured continuously since 1970 in a pristine headwater boreal lake and its catchment at the IISD‐Experimental Lakes Area (Ontario, Canada). Mass balanced accounting of DOC concentrations in precipitation, watershed runoff, and inflow and outflow streams, and integrated weekly hydrological data determined annual mass flux of DOC to and from the lake. Inputs minus outputs represented two residual terms: (1) mineralization and evasion of CO2and (2) DOC flocculation and sediment burial. Accumulation of organic carbon in sediment cores estimated permanent storage and evasion was calculated by subtraction of burial from the annual retention over 40 yr (1971–2010). Terrestrial sources accounted for 92% ± 1% of DOC load; 37% ± 2% of which was lost via the outflow. About 40% ± 3% of DOC load accumulated in sediments and 23 ± 3% was lost as CO2. Over 40 yr, C sequestration in sediments was a more important sink than evasion or outflow. We explore the fate of DOC during decade long periods of differing precipitation patterns. Loading and loss via the outflow was higher in wet (1990–2010) compared to dry (1980–1990) years. Due to longer DOC processing times when water residence times are longer, it is possible that if drought increases in the boreal forest, the efficiency of headwater lakes to sequester C in sediments maybe greater than in wet periods.

ABSTRACTAristotle held that humans had three basic activities each of which were directed towards a distinct goal or telos: theoria,thinking or analysing, directed towards the pursuit of truth; poiesis, making or bringing forth, directed towards crafting or producing and praxis, doing or applying a skill, directed towards action. In terms of theoria, this article critiques the pastoral cycle; enumerates five categories of reflection and outlines an approach to the reflection that fosters dialogue between soul, role and context. It goes on to craft and shape that thinking in story, image and autoethnographic writing with the aim of bringing forth the reader’s own creative performance (poiesis). It concludes by exploring the relevance of, and challenges to, reflective practice for practical theologians (praxis).

A total of 15 kg of silver nanoparticles (AgNPs) was added continuously over two ice-free field seasons to a boreal lake (i.e., Lake 222) at the IISD Experimental Lakes Area in Canada. We monitored the accumulation of silver (Ag) in the tissues of yellow perch (Perca flavescens) and northern pike (Esox lucius) exposed to the AgNPs under environmentally relevant conditions. The greatest accumulation was observed in the liver tissues of pike, and a single pike sampled in the second year of additions had the highest concentration observed in liver of 5.1 micrograms per gram of wet weight. However, the Ag concentrations in gill and muscle tissue of both pike and perch did not exceed 0.35 micrograms per gram of wet weight. Following additions of AgNP, the Ag residues in fish tissues declined, with a half-life of Ag in pike liver of 119 days. Monitoring using passive sampling devices and single-particle inductively coupled plasma mass spectrometry during the AgNP addition phase confirmed that Ag nanoparticles were present in the water column and that estimated mean concentrations of Ag increased over time to a maximum of 11.5 μg/L. These data indicate that both a forage fish and a piscivorous fish accumulated Ag in a natural lake ecosystem dosed with AgNPs, leading to Ag concentrations in some tissues of the piscivorous species that were 3 orders of magnitude greater than the concentrations in the water.

Objective To determine whether alveolar bone graft outcomes for unilateral and bilateral cleft lip and palate patients have continued to improve since the reorganization of cleft services in Scotland in 2000.Design Retrospective analysis of postoperative anterior occlusal radiographs. Patients and Participants: Eighty-one of 106 patients who were eligible for alveolar bone grafting between 2007 and 2010 had suitable postoperative radiographs available.Interventions Twenty-seven percent of the patients (n = 22) had presurgical orthodontic intervention. All patients underwent alveolar bone grafting with bone harvested from the iliac crest.Main Outcome Measures The Kindelan bone-fill index was used to evaluate success. Weighted kappa statistics were used to assess intra- and interobserver reproducibility. A comparison was made with results from 2000 to 2004 to assess any improvement. Chi-square tests (or Fisher exact test) were used to determine whether outcomes differed depending on the laterality of the cleft, use of presurgical expansion, or age at bone grafting.Result Interobserver scoring agreement was good (weighted kappa = .383). Intraobserver reproducibility was greater (weighted kappas of .835 and .620). Success was achieved in 99% of bone grafts, compared with 76% in the period from 2000 to 2004 (P < .001). There was no statistically significant relationship between the laterality of the cleft (P = 1.000), use of presurgical expansion (P = 1.000), or age at time of bone grafting and outcome (P = .259).Conclusion Scottish secondary alveolar bone graft outcomes improved during 2007 to 2010 in comparison to the 2000 to 2004 results.

Supplemental digital content is available in the text.Small studies suggest that prescription stimulants can precipitate psychosis and mania. We conducted a population-based case-crossover study to examine whether hospitalization for psychosis or mania was associated with initiation of stimulant therapy. Between October 1, 1999 and March 31, 2013, we studied 12,856 young people who received a stimulant prescription and were subsequently hospitalized for psychosis or mania. Of these, 183 commenced treatment during 1 of 2 prespecified 60-day intervals (defined as the “risk interval” and “control interval,” respectively) prior to admission. We found that stimulant initiation was associated with an increased risk of hospitalization for psychosis or mania in the subsequent 60 days (odds ratio, 1.86; 95% confidence interval, 1.39–2.56). The risk was marginally higher in patients treated with antipsychotic drugs (odds ratio, 2.06; 95% confidence interval, 1.38–3.28), but remained in patients with no such history (odds ratio, 1.66; 95% confidence interval, 1.09–2.66). One third of subjects received another stimulant prescription after hospital discharge. Of these, 45% were readmitted with psychosis or mania shortly thereafter. We conclude that initiation of prescription stimulants is associated with an increased risk of hospitalization for psychosis or mania. Resumption of therapy is common, which may reflect a lack of awareness of the potential causative role of these drugs.

Supplemental Digital Content Is Available in the Text.

To examine whether postpartum treatment with oxycodone is associated with an increased risk of new persistent opioid use relative to codeine.

This series of articles has explored the changing face of contemporary healthcare chaplaincy. In this final article, the author proposes a way through disorientation (article one) and imbalances of power (article two) to a future in which patients offer a leading role in shaping chaplains’ spirituality (ontology) and formation (epistemology).

In the first of this series of three articles in Health & Social Care Chaplaincy, the author employed Ricoeur’s typology – orientation, disorientation, reorientation – to explore Scottish healthcare chaplains’ responses to the refocusing of spiritual care from a series of crisis-based hospital interventions to the promotion of wellbeing and resilience in local communities. In this second article the author treats this paradigm shift with a hermeneutic of suspicion and explores inherent issues of need, ability, value and power.

Institutionally-based crisis intervention, the traditional hallmark of healthcare chaplaincy, is under review as new initiatives in health and social care refocus the spotlight from responding to the needs of those in hospital to the promotion of wellbeing and resilience in local communities. In the first of three articles, the author reports the findings of a Review of Chaplaincy Education, Training and Formation conducted in Scotland in 2013. He explores the impact of shifting paradigms on healthcare chaplains using Ricoeur’s typology of orientation, disorientation and reorientation.

Eliciting stories is the bread and butter of healthcare chaplaincy but only the naïve would think that storytelling is value free or one directional. Chaplains themselves are bearers of stories which motivate and inspire, support and challenge. Creating spaces for the micro stories of clinical practice to be heard against the backdrop of wisdombearing macro stories lies at the heart of Values-based Reflective Practice. The author outlines some of the challenges and graces inherent within such reflection.

Excerpted from a Keynote Address at the Annual Conference of the Association of Hospice and Palliative Care Chaplains, The Hayes Centre, Swanwick, 16 May 2011

Objective.Administrative data are increasingly being used for research and surveillance about rheumatic diseases. However, literature reviews have revealed a lack of consistency in methods for conducting observational rheumatic disease studies, a situation that can lead to findings that cannot be compared. Our purpose was to develop best-practice consensus statements about the use of administrative data for rheumatic disease research and surveillance in Canada.Methods.We convened 52 decision makers, epidemiologists, clinicians, and researchers to a 2-day workshop. Prior to this, participants formed working groups to examine 3 best-practice categories: case definitions, epidemiology methods, and comorbidity and outcomes measurement. The groups conducted systematic or scoping reviews on key topics. At the workshop, evidence from the reviews was presented and consensus-building techniques were used to develop the best-practice statements. The statements were presented, discussed, revised (as needed), and then subjected to voting.Results.Thirteen best-practice consensus statements were developed and endorsed by consensus. For the first category, these consensus statements addressed validation techniques for rheumatic disease case definitions and case ascertainment bias. The consensus statements for epidemiology methods focused on confounding and drug exposure measurement. For comorbidity and outcomes measurement, consensus statements were developed for multiple conditions, including osteoporosis and fragility fractures, cancer, infections, cardiovascular disease, and renal disease. Strengths and limitations of administrative data were identified in relation to each topic.Conclusion.Our best-practice consensus statements are consistent with other recent guidelines, including those for rheumatic disease biologics registries, but address additional issues specific to administrative data. Continuing work focuses on disseminating these consensus statements to multiple audiences.

Background:Acute kidney injury is a serious complication of elective major surgery. Acute dialysis is used to support life in the most severe cases. We examined whether rates and outcomes of acute dialysis after elective major surgery have changed over time.Methods:We used data from Ontario’s universal health care databases to study all consecutive patients who had elective major surgery at 118 hospitals between 1995 and 2009. Our primary outcomes were acute dialysis within 14 days of surgery, death within 90 days of surgery and chronic dialysis for patients who did not recover kidney function.Results:A total of 552 672 patients underwent elective major surgery during the study period, 2231 of whom received acute dialysis. The incidence of acute dialysis increased steadily from 0.2% in 1995 (95% confidence interval [CI] 0.15–0.2) to 0.6% in 2009 (95% CI 0.6–0.7). This increase was primarily in cardiac and vascular surgeries. Among patients who received acute dialysis, 937 died within 90 days of surgery (42.0%, 95% CI 40.0–44.1), with no change in 90-day survival over time. Among the 1294 patients who received acute dialysis and survived beyond 90 days, 352 required chronic dialysis (27.2%, 95% CI 24.8–29.7), with no change over time.Interpretation:The use of acute dialysis after cardiac and vascular surgery has increased substantially since 1995. Studies focusing on interventions to better prevent and treat perioperative acute kidney injury are needed.

Stable Fe isotopes have only recently been measured in freshwater systems, mainly in meromictic lakes. Here we report the δ56Fe of dissolved, particulate, and sediment Fe in two small dimictic boreal shield headwater lakes: manipulated eutrophic Lake 227, with annual cyanobacterial blooms, and unmanipulated oligotrophic Lake 442. Within the lakes, the range in δ56Fe is large (ca. −0.9 to +1.8‰), spanning more than half the entire range of natural Earth surface samples. Two layers in the water column with distinctive δ56Fe of dissolved (dis) and particulate (spm) Fe were observed, despite differences in trophic states. In the epilimnia of both lakes, a large Δ56Fedis-spmfractionation of 0.4–1‰ between dissolved and particulate Fe was only observed during cyanobacterial blooms in Lake 227, possibly regulated by selective biological uptake of isotopically light Fe by cyanobacteria. In the anoxic layers in both lakes, upward flux from sediments dominates the dissolved Fe pool with an apparent Δ56Fedis-spmfractionation of −2.2 to −0.6‰. Large Δ56Fedis-spmand previously published metagenome sequence data suggest active Fe cycling processes in anoxic layers, such as microaerophilic Fe(II) oxidation or photoferrotrophy, could regulate biogeochemical cycling. Large fractionation of stable Fe isotopes in these lakes provides a potential tool to probe Fe cycling and the acquisition of Fe by cyanobacteria, with relevance for understanding biogeochemical cycling of Earth’s early ferruginous oceans.

OBJECTIVE To examine the effect of cost-sharing on the use of asthma medications in asthmatic children. According to asthma guidelines, children with asthma may require treatment with multiple medications, including controllers and relievers, to achieve optimal control. Although families may be enrolled in drug benefit plans, impediments to access persist in the form of cost-sharing. DESIGN Population-based retrospective cohort study of children by analysis of administrative medication insurance claims data. SETTING Ontario, Canada. PARTICIPANTS A cohort of 17 046 Ontario children with asthma enrolled in private drug plans. MAIN EXPOSURE We used data on out-of-pocket expenses and reimbursement for medications to classify children as having zero, low (&lt; 20%), or high (≥ 20%) levels of cost-sharing. MAIN OUTCOME MEASURES We examined use of bronchodilators, inhaled corticosteroids, leukotriene receptor antagonists, oral corticosteroids, and combination agents. Multiple linear and logistic regressions compared medication use between cost-sharing groups, controlling for age and sex. RESULTS The annual number of asthma medication claims per child was significantly lower in the high cost-sharing group (6.6) compared with the zero (7.0) and low (7.2) cost-sharing groups (P &lt; .001). Children in the high cost-sharing group were less likely to purchase bronchodilators, inhaled corticosteroids, and leukotriene receptor antagonists compared with the low cost-sharing group (odds ratio, 0.76; 95% confidence interval, 0.67-0.86) and were less likely to purchase dual agents compared with the low cost-sharing group (odds ratio, 0.70; 95% confidence interval, 0.66-0.75). CONCLUSION The cost-sharing level affected the use of asthma medication, with the highest cost-sharing group exhibiting significantly lower use of maintenance medications and newer dual agents.Arch Pediatr Adolesc Med. 2008;162(2):104-110--

A high-yield preparation of the C-monoethynyl para-carborane, 1-Me3SiCC-1,12-C2B10H11, from C-monocopper para-carborane and 1-bromo-2-(trimethylsilyl)ethyne, BrCCSiMe3is reported. The low-yield preparation of 1,12-(Me3SiCC)2-1,12-C2B10H10from the C,C′-dicopper para-carborane derivative with 1-bromo-2-(trimethylsilyl)ethyne, BrCCSiMe3, has been re-investigated and other products were identified including the C-monoethynyl-carborane 1-Me3SiCC-1,12-C2B10H11and two-cage assemblies generated from cage–cage couplings. The contrast in the yields of the monoethynyl and diethynyl products is due to the highly unfavourable coupling process between 1-RCC-12-Cu-1,12-C2B10H10and the bromoalkyne. The ethynyl group at the cage carbon C(1) strongly influences the chemical reactivity of the cage carbon at C(12)—the first example of the ‘antipodal effect’ affecting the syntheses of para-carborane derivatives. New two-step preparations of 1-ethynyl- and 1,12-bis(ethynyl)-para-carboranes have been developed using a more readily prepared bromoethyne, 1-bromo-3-methyl-1-butyn-3-ol, BrCCCMe2OH. The molecular structures of the two C-monoethynyl-carboranes, 1-RCC-1,12-C2B10H11(R = H and Me3Si), were experimentally determined using gas-phase electron diffraction (GED). For R = H (RG= 0.053) a model with C5vsymmetry refined to give a CC bond distance of 1.233(5) Å. For R = Me3Si (RG= 0.048) a model with Cssymmetry refined to give a CC bond distance of 1.227(5) Å. Molecular structures of 1,12-Br2-1,12-C2B10H10, 1-HCC-12-Br-1,12-C2B10H10and 1,12-(Me3SiCC)2-1,12-C2B10H10were determined by X-ray crystallography. Substituents at the cage carbon atoms on the C2B10cage skeleton in 1-X-12-Y-1,12-C2B10H10derivatives invariably lengthen the cage C–B bonds. However, the subtle substituent effects on the tropical B–B bond lengths in these compounds are more complex. The molecular structures of the ethynyl-ortho-carborane, 1-HCC-1,2-C2B10H11and the ethene, trans-Me3SiBrCCSiMe3Br are also reported.

The influence of molecular conformation on the oxidation ionisation potential and electronic structure associated with several TPD-style hole transport materials has been assessed through a combination of single crystal X-ray diffraction, electrochemical and spectroelectrochemical methods and DFT calculations. The introduction of methyl groups can be used to tune the ionisation potential of these molecular species through a combination of electronic inductive and thermodynamic effects, while the conformation of the biphenyl portion of the molecular framework is found to play the greatest role in determining the Marcus-type reorganisation energy associated with the charge transport process on the molecular level.

Oxidation of N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine (TPD, 1 a) and N,N'-diphenyl-N,N'-bis(2,4-dimethylphenyl)-(1,1'-biphenyl)-4,4'-diamine (1 b) with SbCl5 affords the corresponding radical cations quantitatively. The crystal and molecular structure of 1 b and [1 b]SbCl6, the first tetraphenyl benzidene derivatives to be characterised crystallographically in both the neutral and radical cation states, reveal molecular parameters in agreement with the predictions made on the basis of DFT studies. Analysis of the NIR transition in the radical cations [1]^+. allows an estimate of the electronic coupling parameter V (1 a^+. 3200 cm⁻¹; 1 b^+. 3300 cm⁻¹), the reorganisation energy λ(1 a^+. 7500 cm⁻¹; 1 b^+. 7800 cm⁻¹), and the linear coupling constant l (1 a^+. 3100 cm⁻¹; 1 b^+. 2700 cm⁻¹) of the symmetric mode.

Oxidation of N,N′‐diphenyl‐N,N′‐bis(3‐methylphenyl)‐(1,1′‐biphenyl)‐4,4′‐diamine (TPD, 1 a) and N,N′‐diphenyl‐N,N′‐bis(2,4‐dimethylphenyl)‐(1,1′‐biphenyl)‐4,4′‐diamine (1 b) with SbCl5affords the corresponding radical cations quantitatively. The crystal and molecular structure of 1 band [1 b]SbCl6, the first tetraphenyl benzidene derivatives to be characterised crystallographically in both the neutral and radical cation states, reveal molecular parameters in agreement with the predictions made on the basis of DFT studies. Analysis of the NIR transition in the radical cations [1]+.allows an estimate of the electronic coupling parameter V(1 a+.3200 cm−1; 1 b+.3300 cm−1), the reorganisation energy λ(1 a+.7500 cm−1; 1 b+.7800 cm−1), and the linear coupling constant l(1 a+.3100 cm−1; 1 b+.2700 cm−1) of the symmetric mode.