Current advances and gaps in knowledge on personalizing masks for non-invasive respiratory support: a scoping review.

Non-invasive respiratory support delivered through a face mask has become a cornerstone treatment for adults and children with acute or chronic respiratory failure. However, an imperfect mask fit using commercially available interfaces is frequently encountered, which may result in patient discomfort and treatment inefficiency or failure. To overcome this challenge, over the last decade increasing attention has been given to the development of personalized face masks, which are custom made to address the specific facial dimensions of an individual patient. With this scoping review we aim to provide a comprehensive overview of the current advances and gaps in knowledge regarding the personalization of ventilation masks. We performed a systematic search of the literature, and identified and summarized a total of 23 studies. Most studies included were involved in the development of nasal masks. Studies targeting adult respiratory care mainly focused on chronic (home) ventilation and included some clinical testing in a relevant subject population. In contrast, pediatric studies focused mostly on respiratory support in the acute setting, while testing was limited to bench or case studies only. Most studies were positive regarding the performance (i.e. comfort, level of air leak and mask pressure applied to the skin) of personalized masks in bench testing or in human, healthy or patient, subjects. Advances in the field of 3D scanning and soft material printing were identified, but important gaps in knowledge remain. In particular, more insight into cushion materials, headgear design, clinical feasibility and cost-effectiveness is needed, before definite recommendations can be made regarding implementation of large scale clinical programs that personalize non-invasive respiratory support masks for adults and children.

"We have dealt with so much. There's more coming?": Improving Knowledge About Brain Health in Adults Living With Congenital Heart Disease.

Background: Significant advances in managing congenital heart disease (CHD) have occurred over the past few decades, resulting in a fast-growing adult patient population with distinct needs requiring urgent attention. Research has recently highlighted the prevalence of neurocognitive differences among adults living with CHD. Yet, there is a lack of knowledge about the perspectives of people living with CHD and family members/caregivers on brain health. We sought to explore their perspectives to guide future research and clinical endeavours. Methods: Using the principles of integrated knowledge translation and qualitative interpretive description, we conducted 2 focus groups with 7 individuals with CHD and their family members as part of a virtual forum on brain health in CHD. Data analysis followed the principles of interpretive description. Results: A lack of understanding about overall brain health and neurocognitive differences in adult CHD was identified. To increase overall knowledge about brain health, initiatives should (1) focus on the individual living with CHD, involving family members and peers; (2) use social media and health care encounters for knowledge exchange; and (3) ensure a "balancing act" in the information provided to avoid feelings of worry and uncertainty about the future while simultaneously empowering people living with CHD. Conclusions: There is a pressing need for better education about brain health among individuals living with CHD. Our findings can guide clinicians in developing programmes of care and (re)design health services that address the brain-heart axis and neurocognitive differences in CHD.

Contexte: Des progrès significatifs ont été réalisés au cours des dernières décennies dans la prise en charge des cardiopathies congénitales, et il en résulte une croissance rapide de la population des patients adultes dont les besoins distincts requièrent une attention urgente. Des études récentes ont mis en évidence la prévalence des différences neurocognitives chez les adultes atteints de cardiopathies congénitales (CC). À ce jour, les connaissances sur les points de vue des personnes qui vivent avec la CC, des membres de leurs familles et de leurs aidants au sujet de la santé du cerveau sont insuffisantes. Notre objectif était d'explorer ces points de vue afin d'orienter les recherches à venir et les initiatives cliniques. Méthodologie: En nous basant sur les approches d'application des connaissances intégrées et de description interprétative (DI) qualitative, nous avons organisé deux groupes de discussion avec 7 personnes atteintes de CC et les membres de leur famille, dans le cadre d'un forum virtuel sur la santé du cerveau dans les CC. L'analyse des données a été réalisée selon les principes de la DI. Résultats: Un manque de connaissances au sujet de la santé du cerveau en général et des différences neurocognitives chez les personnes atteintes de CC a été observé. Afin d'améliorer le niveau des connaissances générales sur la santé du cerveau, les initiatives doivent : (1) être centrées sur les personnes qui vivent avec la CC, avec la participation des membres de leur famille et d'autres patients; (2) tirer profit des médias sociaux et des rencontres en contexte de soins de santé pour le partage de connaissances; et (3) veiller à maintenir un équilibre, puisqu'il convient d'outiller les personnes atteintes de CC sans toutefois causer de sentiment d'inquiétude ou d'incertitude quant à l'avenir. Conclusions: Nous avons constaté le besoin urgent d'améliorer les connaissances des personnes qui vivent avec une CC au sujet de la santé du cerveau. Les résultats obtenus pourront guider les cliniciens dans l'élaboration de programmes de soins et la conception (ou la refonte) de services de soins de santé qui intègrent l'axe cerveau-cœur et les différences neurocognitives associées aux CC.

Collisional Relaxation of Highly Vibrationally Excited Acetylene Mediated by the Vinylidene Isomer.

Collisional relaxation of highly vibrationally excited acetylene, generated from the 193 nm photolysis of vinyl bromide with roughly 23,000 cm-1 of nascent vibrational energy, is studied via submicrosecond time-resolved Fourier transform infrared (FTIR) emission spectroscopy. IR emission from vibrationally hot acetylene during collisional relaxation by helium, neon, argon, and krypton rare-gas colliders is recorded and analyzed to deduce the acetylene energy content as a function of time. The average energy lost per collision, ⟨ΔE⟩, is computed using the Lennard-Jones collision frequency. Two distinct vibrational-to-translational (V-T) energy transfer regimes in terms of the acetylene energy are identified. At vibrational energies below 10,000-14,000 cm-1, energy transfer efficiency increases linearly with molecular energy content and is in line with typical V-T behavior in quantity. In contrast, above 10,000-14,000 cm-1, the V-T energy transfer efficiency displays a dramatic and rapid increase. This increase is nearly coincident with the acetylene-vinylidene isomerization limit, which occurs nearly 15,000 cm-1 above the acetylene zero-point energy. Combined quasi-classical trajectory calculations and Schwartz-Slawsky-Herzfeld-Tanczos theory point to a vinylidene contribution being responsible for the large enhancement. This observation illustrates the influence of energetically accessible structural isomers to greatly enhance the energy transfer rates of highly vibrationally excited molecules.

Anti-vascular endothelial growth factors in combination with vitrectomy for complications of proliferative diabetic retinopathy.

BACKGROUND: Vitrectomy is an established treatment for the complications of proliferative diabetic retinopathy (PDR). However, a number of complications can occur during and after vitrectomy for PDR. These include bleeding and the creation of retinal holes during surgery, and bleeding, retinal detachment and scar tissue on the retina after surgery. These complications can limit vision, require further surgery and delay recovery. The use of anti-vascular endothelial growth factor (anti-VEGF) agents injected into the eye before surgery has been proposed to reduce the occurrence of these complications. Anti-VEGF agents can reduce the amount and vascularity of abnormal new vessels associated with PDR, facilitating their dissection during surgery, reducing intra- and postoperative bleeding, and potentially improving outcomes. OBJECTIVES: To assess the effects of perioperative anti-VEGF use on the outcomes of vitrectomy for the treatment of complications for proliferative diabetic retinopathy (PDR). SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL; which contains the Cochrane Eyes and Vision Trials Register; 2022, Issue 6); Ovid MEDLINE; Ovid Embase; the ISRCTN registry; ClinicalTrials.gov and the WHO ICTRP. The date of the search was 22 June 2022. SELECTION CRITERIA: We included randomised controlled trials (RCTs) that looked at the use of anti-VEGFs and the incidence of complications in people undergoing vitrectomy for PDR.   DATA COLLECTION AND ANALYSIS: Two review authors independently assessed and extracted the data. We used the standard methodological procedures expected by Cochrane. The critical outcomes of the review were the mean difference in best corrected visual acuity (BCVA) between study arms at six (± three) months after the primary vitrectomy, the incidence of early postoperative vitreous cavity haemorrhage (POVCH, within four weeks postoperatively), the incidence of late POVCH (occurring more than four weeks postoperatively), the incidence of revision surgery for POVCH within six months, the incidence of revision surgery for recurrent traction/macular pucker of any type and/or rhegmatogenous retinal detachment within six months and vision-related quality of life (VRQOL) measures. Important outcomes included the proportion of people with a visual acuity of counting fingers (1.8 logMAR or worse), the number of operative retinal breaks reported and the frequency of silicone oil tamponade required at time of surgery. MAIN RESULTS: The current review includes 28 RCTs that looked at the pre- or intraoperative use of intravitreal anti-VEGFs to improve the outcomes of pars plana vitrectomy for complications of PDR. The studies were conducted in a variety of countries (11 from China, three from Iran, two from Italy, two from Mexico and the remaining studies from South Korea, the UK, Egypt, Brazil, Japan, Canada, the USA, Indonesia and Pakistan). The inclusion criteria for entry into the studies were the well-recognised complications of proliferative retinopathy: non-clearing vitreous haemorrhage, tractional retinal detachment involving the macula or combined tractional rhegmatogenous detachment. The included studies randomised a total of 1914 eyes.  We identified methodological issues in all of the included studies. Risk of bias was highest for masking of participants and investigators, and a number of studies were unclear when describing randomisation methods and sequence allocation. Participants receiving intravitreal anti-VEGF in addition to pars plana vitrectomy achieved better BCVA at six months compared to people undergoing vitrectomy alone (mean difference (MD) -0.25 logMAR, 95% confidence interval (CI) -0.39 to -0.11; 13 studies, 699 eyes; low-certainty evidence). Pre- or intraoperative anti-VEGF reduced the incidence of early POVCH (12% versus 31%, risk ratio (RR) 0.44, 95% CI 0.34 to 0.58; 14 studies, 1038 eyes; moderate-certainty evidence). Perioperative anti-VEGF use was also associated with a reduction in the incidence of late POVCH (10% versus 23%, RR 0.47, 95% CI 0.30 to 0.74; 11 studies, 579 eyes; high-certainty evidence). The need for revision surgery for POVCH occurred less frequently in the anti-VEGF group compared with control, but the confidence intervals were wide and compatible with no effect (4% versus 13%, RR 0.44, 95% CI 0.15 to 1.28; 4 studies 207 eyes; moderate-certainty evidence). Similar imprecisely measured effects were seen for revision surgery for rhegmatogenous retinal detachment (5% versus 11%, RR 0.50, 95% CI 0.15 to 1.66; 4 studies, 145 eyes; low-certainty evidence).  Anti-VEGFs reduce the incidence of intraoperative retinal breaks (12% versus 31%, RR 0.37, 95% CI 0.24 to 0.59; 12 studies, 915 eyes; high-certainty evidence) and the need for silicone oil (19% versus 41%, RR 0.46, 95% CI 0.27 to 0.80; 10 studies, 591 eyes; very low-certainty evidence). No data were available on quality of life outcomes or the proportion of participants with visual acuity of counting fingers or worse. AUTHORS' CONCLUSIONS: The perioperative use of anti-VEGF reduces the risk of late POVCH, probably results in lower early POVCH risk and may improve visual outcomes. It also reduces the incidence of intraoperative retinal breaks. The evidence is very uncertain about its effect on the need for silicone oil tamponade. The reported complications from its use appear to be low. Agreement on variables included and outcome standardisation is required in trials studying vitrectomy for PDR.

Neurodevelopment and Cognition Across the Lifespan in Patients With Single-Ventricle Physiology: Abnormal Brain Maturation and Accumulation of Brain Injuries.

The proportion of adults with single-ventricle physiology (SVP) has significantly increased over time. Improved longevity, however, may be associated with increased risks to brain health in adulthood. Children with SVP are at risk for neurodevelopmental impairment early in life and neurocognitive impairment as they age, and existing epidemiologic evidence suggests that adults with complex congenital heart disease, including SVP, are at increased risk of stroke and dementia, as compared with age-matched controls. Mechanisms that could contribute to increased potential for cognitive impairment in adults with SVP include the following: (i) baseline brain dysmaturation beginning in utero; (ii) subsequent acquired injury occurring in early childhood from staged surgeries; and (iii) pathophysiologic factors related to SVP itself, both in childhood and potentially throughout the lifespan as new arrhythmias, heart failure, and other issues may develop. Associated pathophysiologic mechanisms may include thromboembolism, hypercoagulability, hypoxia, hypoperfusion, and inflammation. Despite increasingly robust pediatric literature with neuroradiologic-neuropsychology correlates in SVP, there is a dearth of similar research in adults, with respect to both complex congenital heart disease overall and SVP specifically. Unanswered questions in adults with SVP include the following: (i) what is the prevalence of baseline brain injury and neurocognitive impairment in adulthood; (ii) what is the incident risk of these issues over time; and (iii) how much may be mediated by incident brain injury across the lifespan in adulthood, as opposed to from underlying susceptibility from dysmaturation and early childhood insults. In this review, we describe what is known regarding the brain health in individuals with SVP across the lifespan, and identify priority areas for future research.

Neurocognition in Adult Congenital Heart Disease: How to Monitor and Prevent Progressive Decline.

Children born with congenital heart disease (CHD) are now living to adulthood in unprecedented numbers and many will eventually live to become senior citizens. As care goals shift from surviving to thriving, a new focus on quality of life has emerged. Neurocognition and the ability to participate fully in society, form meaningful relationships, and collaborate effectively with the health care system are important considerations. As adults with CHD age, research regarding their cognitive function becomes prescient. The focus is now shifting from defining neurocognitive deficits in children with CHD to preventing neurocognitive decline in adults living with CHD. In this review, we describe the possible etiologies and predictors of neurocognitive decline in adults with CHD. We performed a comprehensive literature review to identify all of the current data available on neurocognitive function in adults with CHD. We summarize the available evidence by describing common deficits in this patient population and the potential effects of these deficits on adult functioning, health care decision-making, and long-term relationships with care providers. We review potential modifiable etiologies for progressive neurocognitive decline and suggest strategies for surveillance and prevention of the potential decline. We conclude that the current information available regarding the aging brain of adults with CHD and the effect of neurocognitive decline on morbidity and mortality is woefully insufficient. This review, therefore, provides a roadmap for future research endeavours to study neurocognition in older adults with CHD.

Adults With Complex Congenital Heart Disease: Cerebrovascular Considerations for the Neurologist.

As infant and childhood mortality has decreased in congenital heart disease, this population is increasingly reaching adulthood. Adults with congenital heart disease (ACHD) represent a group with increased risk of stroke, silent brain infarcts, and vascular cognitive impairment. Cyanotic and other complex cardiac lesions confer the greatest risk of these cerebrovascular insults. ACHD patients, in addition to having an increased risk of stroke from structural cardiac issues and associated physiological changes, may have an accelerated burden of conventional vascular risk factors, including hypertension and impaired glucose metabolism. Adult neurologists should be aware of the risks of clinically evident and subclinical cerebrovascular disease in this population. We review the existing evidence on primary and secondary stroke prevention in individuals with complex congenital heart disease, and identify knowledge gaps in need of further research, including treatment of acute stroke in this population. Multisystemic genetic syndromes are outside the scope of this review.

Development and Validation of the Parent-Initiated Motivational Climate in Individual Sport Competition Questionnaire.

This paper presents a series of studies that progresses the development and validation of the Parent-Initiated Motivational Climate in Individual Sport Competition Questionnaire (MCISCQ-Parent). Study 1 examined the face and content validity of an initial pool of 26 items based on the principles of achievement goal theory and prior research. In Study 2, data from an adolescent sample of individual sport athletes was subjected to an exploratory factor analysis (EFA) of items pertaining to the perceived task and ego involving characteristics of fathers and mothers in the competition setting. Study 3 tested the factor structure of the MCISCQ-Parent through confirmatory factor analysis (CFA) in a further youth athlete sample. Following appropriate CFA-related modifications, good goodness of fit indices emerged for the father- (three factor-model) and mother-related (two factor-model) dimensions of motivational climate. In Study 4, a further CFA was conducted and provided additional evidence for the revised factor structure of the MCISCQ-Parent, convergent and discriminant validity, and internal consistency. Finally, Study 5 provided support for the concurrent validity of the MCISCQ-Parent by demonstrating significant relationships between MCISCQ-Parent subscales and task and ego orientation, athlete engagement, and perceived social support. In sum, we present the MCISCQ-Parent as a measure with promising psychometric properties, and specifically to those applied researchers interested in assessing the quality of motivation-related parental involvement perceived by young athletes in the competition setting.

UV Photolysis of Pyrazine and the Production of Hydrogen Isocyanide.

Photolysis of the diazine heterocycle, pyrazine, following irradiation at 308, 248, and 193 nm was examined using nanosecond time-resolved Fourier transform infrared emission spectroscopy. The resulting time-resolved IR emission spectra reveal that for 308 and 248 nm vibrationally highly excited pyrazine is produced, but no photolysis products were detected. However, at 193 nm excitation, the measured IR emission spectra consist solely of resonances originating from rovibrationally excited photofragments, including acetylene (HCCH), hydrogen cyanide (HCN), and hydrogen isocyanide (HNC), indicating that photofragmentation proceeds from vibrationally highly excited pyrazine on the ground electronic state. Spectral fit analysis of the time-resolved HCN and HNC IR emission band shapes and intensities allowed an estimate of the nascent product population distributions, from which a lower bound estimate of the HNC/HCN branching ratio was deduced as Φ ≥ 0.07. Additionally, ab initio calculations were performed in order to examine the propensity of photoinduced reactions on the ground- and lowest-energy excited-state surfaces. The calculations provide a basis for understanding the wavelength dependence of the UV photolysis of pyrazine, the photolytic production of HNC, and also explain previous experimental observations in the literature.

A rare case of acute angle closure due to spontaneous suprachoroidal haemorrhage secondary to loss of anti-coagulation control: a case report.

BACKGROUND: Suprachoroidal haemorrhage is a rare complication of either medical anticoagulation treatment or intraocular surgical procedures. Suprachoroidal haemorrhages often have devastating visual outcome despite conservative and/or surgical intervention. CASE PRESENTATION: A patient with known Open Angle Glaucoma and Atrial Fibrillation on warfarin presents symptoms and signs suggestive acute angle closure. Examination reveals the underlying cause is a large, macula involving, spontaneous suprachoroidal haemorrhage secondary to loss of anti-coagulation control. Following aggressive medical treatment and surgical intervention, including drainage combined cataract extraction with intraocular lens implant, pars-plana vitrectomy, and external drainage of suprachoroidal haematoma, we managed to preserve the patient's eye and some of its function. CONCLUSION: Spontaneous suprachoroidal haemorrhages are rare complications of loss of anticoagulation control. Our case shows that aggressive treatment in selected cases can offer a relatively good outcome.

Spectral reconstruction analysis for enhancing signal-to-noise in time-resolved spectroscopies.

We demonstrate a new spectral analysis for the enhancement of the signal-to-noise ratio (SNR) in time-resolved spectroscopies. Unlike the simple linear average which produces a single representative spectrum with enhanced SNR, this Spectral Reconstruction analysis (SRa) improves the SNR (by a factor of ca. 0.6√n) for all n experimentally recorded time-resolved spectra. SRa operates by eliminating noise in the temporal domain, thereby attenuating noise in the spectral domain, as follows: Temporal profiles at each measured frequency are fit to a generic mathematical function that best represents the temporal evolution; spectra at each time are then reconstructed with data points from the fitted profiles. The SRa method is validated with simulated control spectral data sets. Finally, we apply SRa to two distinct experimentally measured sets of time-resolved IR emission spectra: (1) UV photolysis of carbonyl cyanide and (2) UV photolysis of vinyl cyanide.

Anti-vascular endothelial growth factor for prevention of postoperative vitreous cavity haemorrhage after vitrectomy for proliferative diabetic retinopathy.

BACKGROUND: Postoperative vitreous cavity haemorrhage (POVCH) is a significant complication following vitrectomy for proliferative diabetic retinopathy (PDR). It delays visual recovery and can make further treatment difficult if the view of the fundus is significantly obscured. A number of interventions to reduce the incidence of POVCH have been proposed, including the perioperative use of anti-vascular endothelial growth factor (anti-VEGF). Anti-VEGFs reduce vascular proliferation and the vascularity of neovascular tissue, which is often the source of bleeding following vitrectomy. OBJECTIVES: This updated review aimed to summarise the effects of anti-VEGF use to reduce the occurrence of POVCH after vitrectomy surgery for PDR. SEARCH METHODS: We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2015, Issue 4), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to May 2015), PubMed (January 1966 to May 2015), EMBASE (January 1980 to May 2015), Latin American and Caribbean Health Sciences (LILACS) (January 1982 to May 2015), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov), and the the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 26 May 2015. SELECTION CRITERIA: We included all randomised controlled trials (RCTs) and quasi-RCTs that looked at the use of anti-VEGFs and the incidence of POVCH in people undergoing vitrectomy for PDR. DATA COLLECTION AND ANALYSIS: Both review authors independently assessed and extracted the data. We used standard methodological procedures expected by Cochrane.The primary outcomes of the review were the incidence of early and late POVCH following perioperative anti-VEGF administration. Secondary outcomes included best-corrected visual acuity at six months following surgery, the incidence of vitreous cavity washout or revision vitrectomy at six months, adverse effects of intervention (cataract, iris rubeosis and rubeotic glaucoma, retinal detachment, increased inflammation and systemic side effects), quality of life measures performed at least six months following vitrectomy, and density of POVCH. MAIN RESULTS: The current review included 12 RCTs that looked at the pre- or intraoperative use of intravitreal bevacizumab to prevent postoperative vitreous haemorrhage during pars plana vitrectomy for complications of PDR. The studies were conducted in a variety of countries (three from Iran, two from Italy, two from Egypt, and the remaining from South Korea, USA, Mexico, Pakistan, and Japan). The inclusion criteria for entry into the studies were standard complications of proliferative retinopathy: non-clearing vitreous haemorrhage, tractional retinal detachment involving the macula, or combined tractional rhegmatogenous detachment. The included studies randomised a total of 654 eyes. The average age of the participants was 54 years.We identified methodological issues in all included studies. Risk of bias was highest for masking of participants and investigators (four studies were an 'open label' design), and a number of studies were unclear when describing randomisation methods and sequence allocation.Participants receiving intravitreal bevacizumab in addition to pars plana vitrectomy were less likely to experience early POVCH (grade 2) compared to people undergoing pars plana vitrectomy alone (risk ratio (RR) 0.28, 95% confidence interval (CI) 0.08 to 0.96, 2 studies, 144 eyes, high-quality evidence). This corresponds to an absolute effect of 130 fewer people (95% CI 167 fewer to 7 fewer) with early POVCH per 1000 people when treated with intravitreal bevacizumab. We saw similar results for all grades of POVCH (RR 0.35, 95% CI 0.23 to 0.53, 9 studies, 512 eyes) and when excluding cases where assessment of outcome was impossible due to presence of silicone oil (RR 0.34, 95% CI 0.19 to 0.60, 6 studies, 302 eyes).The effect of pre- or intraoperative intravitreal bevacizumab on the incidence of late postoperative haemorrhage was uncertain (RR 0.72, 95% CI 0.30 to 1.72, 3 studies, 196 eyes, low-quality evidence). The absolute effect was 55 fewer people (95% CI 138 fewer to 143 more) with late POVCH per 1000 people when treated with intravitreal bevacizumab. This outcome was rarer and was only reported in a few studies. We are currently unable to provide an estimate of the effect of intravitreal bevacizumab on postoperative visual acuity due to significant study heterogeneity.No local or systemic complications of intravitreal bevacizumab were reported by the RCTs. The risk of postoperative retinal detachment was lower in the participants treated with pre- or intraoperative bevacizumab (RR 0.46, 95% CI 0.19 to 1.08, 7 studies, 372 participants, low-quality evidence); the absolute effect was 49 fewer people (95% CI:73 fewer to 8 more) with postoperative retinal detachment per 1000 people when treated with intravitreal bevacizumab. AUTHORS' CONCLUSIONS: The use of pre- or intraoperative bevacizumab lowers the incidence of early POVCH. The reported complications from its use appear to be low. Futher randomised studies that look at other anti-VEGF medications are ongoing and will strengthen the current review findings, giving both surgeons and patients evidence to guide treatment choices in the management of proliferative retinopathy.

Chemical activation through super energy transfer collisions.

Can a molecule be efficiently activated with a large amount of energy in a single collision with a fast atom? If so, this type of collision will greatly affect molecular reactivity and equilibrium in systems where abundant hot atoms exist. Conventional expectation of molecular energy transfer (ET) is that the probability decreases exponentially with the amount of energy transferred, hence the probability of what we label "super energy transfer" is negligible. We show, however, that in collisions between an atom and a molecule for which chemical reactions may occur, such as those between a translationally hot H atom and an ambient acetylene (HCCH) or sulfur dioxide, ET of chemically significant amounts of energy commences with surprisingly high efficiency through chemical complex formation. Time-resolved infrared emission observations are supported by quasi-classical trajectory calculations on a global ab initio potential energy surface. Results show that ∼10% of collisions between H atoms moving with ∼60 kcal/mol energy and HCCH result in transfer of up to 70% of this energy to activate internal degrees of freedom.

Collisional Energy Transfer from Highly Vibrationally Excited Radicals Is Very Efficient.

Although highly vibrationally excited (HVE) radicals are ubiquitous in natural environments, the effect of collisional energy transfer (ET) on their reactivity has yet to be fully characterized. We have used time-resolved IR emission spectroscopy to characterize the vibrational-to-translational quenching of a small HVE radical, ketenyl (HCCO), by inert gases. Photolysis of ethyl ethynyl ether at 193 nm provides HVE HCCO in the X̃(2)A″ electronic ground-state, with a nascent internal energy of 2.2 ± 0.6 eV. IR emission is monitored as an indicator of vibrational energy, and spectral modeling allows direct determination of the average energy lost per collision as a function of the internal energy. Collisional deactivation of HVE HCCO is shown to be minimally an order of magnitude more efficient than closed-shell molecules of comparable size. Schwartz-Slawsky-Herzfeld-Tanczos (SSHT) theory, modified for HVE molecules, suggests that this ET enhancement is due to a strong attractive intermolecular interaction.

Photolysis (193 nm) of SO2: nascent product energy distribution examined through IR emission.

Infrared emission following the photolysis of SO(2) by a 193 nm laser pulse (20 ns duration) was recorded with 500 ns time and 10 cm(-1) spectral resolution. Spectral analyses of the time-resolved spectra revealed the vibrationally excited nascent SO population distribution as (v = 1)/(v = 2)/(v = 3)/(v = 4)/(v = 5) = 0.54 ± 0.04, 1.00 ± 0.03, 0.00 ± 0.03, 0.01 ± 0.03, and 0.10 ± 0.03. The nascent SO was found to be rotationally excited with an average rotational temperature around 1000 K for v = 1 and v = 2 levels and 300 K for the v = 5 level. The vibrationally excited SO likely originates from two distinct dissociation mechanisms; the v = 1 and 2 populations are generated through intersystem crossing between the C state and a repulsive state (2(3)A'), and the v = 5 population is generated through internal conversion from the C to the X state. Efficient V-V energy transfer from nascent vibrationally excited SO to SO(2)(ν(1)) is also observed. The appearance of the SO(2)(ν(1)) ν(1) = 2 emission, before that from the ν(1) = 1 population is consistent with the previous report that the Δν = -2 channel is more efficient than the Δν = -1 channel.

Anti-vascular endothelial growth factor for prevention of postoperative vitreous cavity haemorrhage after vitrectomy for proliferative diabetic retinopathy.

BACKGROUND: Postoperative vitreous cavity haemorrhage (POVCH) is a significant complication following vitrectomy for proliferative diabetic retinopathy (PDR). It delays visual recovery and can make further treatment difficult if the view of the fundus is significantly obscured. A number of interventions to reduce the incidence of POVCH have been proposed, including the perioperative use of anti-vascular endothelial growth factor (anti-VEGF). Anti-VEGFs reduce vascular proliferation and the vascularity of neovascular tissue, which is often the source of bleeding following vitrectomy. OBJECTIVES: The review aims to assess the effect of perioperative anti-VEGF in reducing the incidence of POVCH. SEARCH STRATEGY: We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2011, Issue 2), MEDLINE (January 1950 to March 2011), PubMed (10 March 2011), EMBASE (January 1980 to March 2011), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to March 2011), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com) and ClinicalTrials.gov (www.clinicaltrial.gov). There were no date or language restrictions in the electronic searches for trials. The electronic databases were last searched on 10 March 2011. SELECTION CRITERIA: We included all randomised controlled trials (RCTs) that looked at the use of anti-VEGFs and the incidence of POVCH in people undergoing vitrectomy for PDR. DATA COLLECTION AND ANALYSIS: Both review authors independently assessed and extracted the data using a standardised form based on the CONSORT statement. MAIN RESULTS: We included four studies (202 eyes of 198 participants) in this review. The four RCTs met the inclusion criteria, but we were unable to conduct a meta-analysis due to methodological issues in three of the trials. We have provided a summary of the effects of the interventions. We have also provided a summary of the current literature addressing each primary and secondary outcome. AUTHORS' CONCLUSIONS: Results from one of the included studies support the use of preoperative intravitreal bevacizumab to reduce the incidence of early POVCH. There are currently no other high quality RCTs that support the use of anti-VEGF agents perioperatively to reduce the incidence of early or late POVCH. The remaining studies identified by the search suggest that the preoperative use of bevacizumab may reduce the incidence of early POVCH, but it should be recognised that there are a number of significant methodological issues in these studies that lead us to be cautious when interpreting their findings and make any definitive conclusions unwarranted.