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The use of an angular ligand drives the formation of an irregular Hofmann framework whereby 6-coordinate and rare 5-coordinate FeII species co-exist – the 6-coordinate species show a spin-crossover transition.

The resonance-stabilized 2-methylallyl radical, 2-MA, is considered as a possible intermediate in the formation of polycyclic aromatic hydrocarbons (PAHs) in combustion processes. In this work, we report on its contribution to molecular growth in a high-temperature microreactor and provide mass-selective IR/UV ion dip spectra of the radical, as well as the various jet-cooled reaction products, employing free electron laser radiation in the mid-infrared region. Small (aromatic) hydrocarbons such as fulvene, benzene, styrene, or

Journal of molecular spectroscopy 386, 111629 (2022). doi:10.1016/j.jms.2022.111629, The formation and dissociation mechanisms of polycyclic aromatic hydrocarbons (PAHs) as well as their reactivity with other interstellar molecules are elusive. In this work, we have investigated the electrical discharge chemistry of the PAH naphthalene and acetonitrile, a molecule known to be present in interstellar environments, using a combination of mass-selective IR-UV ion dip spectroscopy with the free electron laser FELIX in the mid-IR frequency region (550 – 1800 cm$^{-1}$), and quantum chemical calculations. In addition to the species known to be produced in the electrical discharge of pure naphthalene, –CH$_3$ and –CN substituted unsaturated hydrocarbons have been identified. Most of them, in particular those containing a nitrogen atom in the molecular framework, such as benzo[7]annulene‐6‐carbonitrile, have a substantial dipole moment and, therefore, can be considered as potential candidates for astronomical searches. Among the species observed, the two isomers 1- and 2-cyanonaphthalene, which have been recently detected in the TMC-1, have been unambiguously identified in our experiment, thus highlighting the use of electrical discharge sources as a valuable tool to produce astronomically relevant species., Published by Academic Press, Orlando, Fla.

Frontiers in physics 10, 880793 (2022). doi:10.3389/fphy.2022.880793 special issue: "Electronic and Nuclear Quantum Dynamics of Molecules in Intense Laser Fields", We report on the use of extreme ultraviolet (XUV, 30.3 nm) radiation from the Free-electron LASer in Hamburg (FLASH) and visible (Vis, 405 nm) photons from an optical laser to investigate the relaxation and fragmentation dynamics of fluorene ions. The ultrashort laser pulses allow to resolve the molecular processes occurring on the femtosecond timescales. Fluorene is a prototypical small polycyclic aromatic hydrocarbon (PAH). Through their infrared emission signature, PAHs have been shown to be ubiquitous in the universe, and they are assumed to play an important role in the chemistry of the interstellar medium. Our experiments track the ionization and dissociative ionization products of fluorene through time-of-flight mass spectrometry and velocity-map imaging. Multiple processes involved in the formation of each of the fragment ions are disentangled through analysis of the ion images. The relaxation lifetimes of the excited fluorene monocation and dication obtained through the fragment formation channels are reported to be in the range of a few tens of femtoseconds to a few picoseconds., Published by Frontiers Media, Lausanne

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The intensity ratio of the 11.2/3.3 µm emission bands is considered to be a reliable tracer of the size distribution of polycyclic aromatic hydrocarbons (PAHs) in the interstellar medium (ISM)....

We investigate the gas-phase structure of the neutral pentaalanine peptide. The IR spectrum in the 340-1820 cm-1 frequency range is obtained by employing supersonic jet cooling, infrared multiphoton dissociation, and vacuum-ultraviolet action spectroscopy. Comparison with quantum chemical spectral calculations suggests that the molecule assumes multiple stable conformations, mainly of two structure types. In the most stable conformation theoretically found, the N-terminus forms a C5 ring and the backbone resembles that of an 310-helix with two beta-turns. Additionally, the conformational preferences of pentaalanine have been evaluated using Born-Oppenheimer molecular dynamics, showing that a nonzero simulation time step causes a systematic frequency shift. Funding Agencies|Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO); Swedish Research Council [2019-04439]

By preventing hypoxia and hypercapnia, advanced airway management can save lives among patients with traumatic brain injury. During endotracheal intubation (ETI), tracheal stimulation causes an increase in intracranial pressure (ICP), which may impair brain perfusion. It has been suggested that intravenous lidocaine might attenuate this ICP response. We hypothesized that adding lidocaine to the standard induction medication for general anesthesia might reduce the ICP response to ETI. Here, we measured the optical nerve sheath diameter (ONSD) as a correlate of ICP and evaluated the effect of intravenous lidocaine on ONSD during and after ETI in patients undergoing anesthesia.This double-blinded, randomized placebo-controlled trial included 60 patients with American Society of Anesthesiologists I or II physical status that were scheduled for elective surgery under general anesthesia. In addition to the standard anesthesia medication, 30 subjects received 1.5 mg/kg 1% lidocaine (0.15 ml/kg, ONSDlidocaine) and 30 received 0.15 ml/kg 0.9% NaCl (ONSDplacebo). ONSDs were measured with ultrasound on the left eye, before (T0), during (T1), and 4 times after ETI (T2-5 at 5-min intervals).Compared to placebo, lidocaine did not significantly affect the baseline ONSD after anesthesia induction measured at T0. During ETI, the ONSDlidocaine was significantly smaller (β=-0.24 mm P=0.022) than the ONSDplacebo. At T4 and T5, the ONSDplacebo increased steadily, up to 20 min after ETI, but the ONSDlidocaine tended to return to baseline levels.We found that the ONSD was distended during and after ETI in anesthetized patients, and intravenous lidocaine attenuated this effect.

Carbon-fiber (CF) plates are a promising alternative to metal plates. However, reported experience in orthopaedic oncology remains limited. The aim of this study was to identify complications of patients with bone tumors treated with CF plates. Between February 2015 and May 2021, 13 centers retrospectively registered patients with bone tumors that were reconstructed using CF plates. Complications were identified, and timing and etiology of complications were noted. Similar complications were tabulated and classified based on mechanical, non-mechanical and paediatric complications. Mechanical complications included: (1) aseptic loosening or graft-host non-union, and (2) structural complications. Non-mechanical complications included: (3) soft tissue complications, (4) infection and (5) tumor progression. Specific paediatric complications included (6) growth arrest resulting in longitudinal or angular deformity. Ninety-six patients were included with a median follow-up time of 35 months. In total, 22 (23%) patients had complications. Mechanical complications included: 1 (1%) aseptic loosening, 2 (2%) non-unions, and 7 (7%) structural complications. Non-mechanical complications included 1 (1%) soft tissue complication, 4 (4%) infections and 5 (5%) tumor progressions. Paediatric complications occurred in 2 (2%) patients. This study suggests CF plates are safe to use in demanding reconstructions after bone tumor resections, presenting a seemingly low complication profile.

Shape-changing mechanical metamaterials have drawn the attention of researchers toward the development of continuous-range tunable frequency selective surfaces (FSSs). In this paper, a novel tunable FSS utilizing an origami-inspired “eggbox” structure is presented featuring four-degrees of freedom that can change the frequency response of two orthogonal linear polarizations. The centrosymmetric “eggbox” structure can be folded or rotated along two axes that lead to unprecedented reconfigurability compared to traditional Miura-Ori-based structures which have fewer degrees of control. The utilized cross-shaped dipole FSS element shows enhanced bandwidth, support for orthogonal linear polarization, and ease of fabrication. The prototype is fabricated using a low-cost fully additive inkjet printing process with silver nanoparticle conductive ink. The outcome of this study shows a 25% frequency tunable range over two polarization directions. The design can be an ideal spatial filtering candidate for advanced ultra-wideband terrestrial and space applications.

Physical chemistry, chemical physics 23(16), 9721 - 9732 (2021). doi:10.1039/D1CP00898F, We report on the noncovalent intermolecular interactions established between the polycyclic aromatic hydrocarbons phenanthrene and phenanthridine with water. Such noncovalent interactions involving extended aromatic systems and water molecules are ubiquitous in a variety of chemical and biological systems. Our study provides spectroscopic results on simple model systems to understand the impact that an extended aromatic surface and the presence of a heteroatom have on the nature of the noncovalent interactions established with the solvent. Microhydrated phenanthrene and phenanthridine clusters with up to three water molecules have been observed and unambiguously characterised by means of broadband rotational spectroscopy and quantum chemical calculations. The presence of a nitrogen atom in the backbone of phenanthridine remarkably affects the geometries of the water clusters and the interaction networks at play, with O–H⋯N and C–H⋯O interactions becoming preferred in the phenanthridine–water clusters over the O–H⋯π interactions seen in the phenanthrene–water clusters. The presence of this heteroatom induces nuclear quadrupole coupling, which was used to understand the cooperativity effects found with increasing cluster size. Our results provide important insight to draw a more complete picture of the noncovalent interactions involving solvent molecules and aromatic systems larger than benzene, and they can be significant to enhance our understanding of the aromatic–polar interactions at play in a myriad of chemical and biological contexts., Published by RSC Publ., Cambridge

A high-power fully-digital Doherty transmitter (DDTX) is proposed. It features two segmented LDMOS output switch banks implemented in a custom V T -down-shifted LDMOS technology. A 40 nm CMOS controller digitally activates the individual LDMOS gate segments of the output stage at RF speed. An inverted Doherty power combiner is proposed that features non-short circuited 2 nd harmonic conditions for the main and peak switch banks to boost the RF bandwidth. To guarantee smooth output power and efficiency vs. frequency, a 2 nd harmonic trap is introduced in the power combiner, yielding an RF bandwidth of > 400 MHz. The realized demonstrator can achieve over 39 W peak output power. Its highest drain and system efficiencies, respectively 60 % and 57 %, were found at 34.2 W of output power, while in power back-off its peak drain and system efficiencies are 52 % and 48 % respectively. Over a 25 dB output range, the system efficiency is within 4 percent points of the drain efficiency.

Resonance-stabilized radicals are considered as possible intermediates in the formation of polycyclic aromatic hydrocarbons (PAHs) in interstellar space. Here, we investigate the fulvenallenyl radical, the most stable C

Summary Postoperative pain might be different after intravenous vs. oral paracetamol. We systematically reviewed randomised controlled trials in patients >15 years that compared intravenous with oral paracetamol for postoperative pain. We identified 14 trials with 1695 participants. There was inconclusive evidence for an effect of route of paracetamol administration on postoperative pain at 0–2 h (734 participants), 2–6 h (766 participants), 6–24 h (1115 participants) and >24 h (248 participants), with differences in standardised mean (95%CI) pain scores for intravenous vs. oral of −0.17 (−0.45 to 0.10), −0.09 (−0.24 to 0.06), 0.06 (−0.12 to 0.23) and 0.03 (−0.22 to 0.28), respectively. Trial sequential analyses suggested that a total of 3948 participants would be needed to demonstrate a meaningful difference in pain or its absence at 0–2 h. There were no differences in secondary outcomes. Intravenous paracetamol is more expensive than oral paracetamol. Substitution of oral paracetamol in half the patients given intravenous paracetamol in our hospital would save around £ 38,711 (€ 43,960 or US$ 47,498) per annum.

Despite Parkinson's Disease (PD) being the second most common neurodegenerative disease, treatment options are limited. Consequently, there is an urgent need to identify and screen new therapeutic compounds that slow or reverse the pathology of PD. Unfortunately, few new therapeutics are being produced, partly due to the low throughput and/or poor predictability of the currently used model organisms and in vivo screening methods. Our objective was to develop a simple and affordable platform for drug screening utilizing the nematode

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Purpose Despite the uncertain effects of anxiolytic premedication with benzodiazepines on the quality of postoperative recovery, perioperative benzodiazepine administration is still a common practice in many hospitals. We evaluated the effect of premedication with midazolam on the quality of recovery in hospitalized patients undergoing a laparotomy. Methods We conducted a single-centre randomized placebo-controlled, double-blinded clinical trial from July 2014 to September 2015. We included 192 patients aged [ 18 yr scheduled for elective laparotomy with a planned postoperative stay of C three days. Participants were randomized into two groups to receive either midazolam 3 mg or sodium chloride 0.9% intravenously as premedication prior to surgery. Patients were followed up for up to one week after surgery. The primary outcome was the Quality of Recovery-40 (QoR-40) score on postoperative day (POD) 3. The secondary outcomes included the QoR-40 score on POD 7, and the StateTrait Anxiety Inventory, State-Trait Anger Scale, Multidimensional Fatigue Inventory, and the Hospital Anxiety and Depression Scale scores. Results The mean (standard deviation) postoperative QoR-40 scores on POD 3 were not significantly different in the midazolam group compared with controls [166.4 (17.0) vs 163.9 (19.8), respectively; mean difference, 2.3; 95% confidence interval, - 2.9 to 8.4; P = 0.35]. There were no between-group differences in any of the secondary outcomes. Conclusions Administration of midazolam as premedication for laparotomy patients did not improve the quality of recovery up to one week after surgery. General prescription of midazolam as premedication can be questioned and might only suit some patients. Trial registration www.clinicaltrials.gov (NCT01993459); registered 29 October, 2013.

Uronic acids are important constituents of polysaccharides found on the cell membranes of different organisms. To prepare uronic-acid-containing oligosaccharides, uronic acid 6,3-lactones can be employed as they display a fixed conformation and a unique reactivity and stereoselectivity. Herein, we report a highly β-selective and efficient mannosyl donor based on C-4 acetyl mannuronic acid 6,3-lactone donors. The mechanism of glycosylation is established using a combination of techniques, including infrared ion spectroscopy combined with quantum-chemical calculations and variable-temperature nuclear magnetic resonance (VT NMR) spectroscopy. The role of these intermediates in glycosylation is assayed by varying the activation protocol and acceptor nucleophilicity. The observed trends are analogous to the well-studied 4,6-benzylidene glycosides and may be used to guide the development of next-generation stereoselective glycosyl donors.

Background Phenylephrine is the preferred vasopressor for the prevention and treatment of spinal anaesthesia-induced hypotension during caesarean section, because studies on low-risk elective patients found it to have a less detrimental effect on umbilical artery pH compared with ephedrine. However, limited data exist from high-risk parturients and parturients with uteroplacental insufficiency. Methods We systematically searched for randomised, controlled, double-blinded trials of these two vasopressors in high-risk caesarean sections. We applied conventional meta-analysis, trial sequential analysis, computing the required information size that would exclude type I and II errors, contour-enhanced funnel plot testing for publication bias, meta-regression to assess the dose–response relationship, and the Grading of Recommendations Assessment, Development, and Evaluation system (GRADE). The incidence of fetal acidosis (umbilical arterial pH Results Eight trials (712 patients) with low risk of bias were identified. Pooling six studies of patients with preeclampsia and other reasons for fetal compromise, as well as subgroup analysis of the preeclampsia studies, revealed no significant differences in the incidence of fetal acidosis. Trial sequential analysis showed that the required information size was not reached. The funnel plot was not suggestive of publication bias. Meta-regression showed no dose-response relationship. The GRADE score was moderate quality. Conclusions Despite several studies and a large number of patients there was insufficient evidence to make a recommendation for choice of vasopressor in high-risk caesarean section. Trials with adequate power to detect differences in the incidence of fetal acidosis between ephedrine and phenylephrine are required to provide evidence-based guidance.

In this article, we report the results of gas-phase IR spectroscopy of neutral glycylglycine (Gly-Gly) in the 700–1850 cm–1 frequency range. A combination of laser desorption, jet-cooling, and IR m...

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The three isomers of the xylyl radical, C8H9, are possible intermediates in the formation of soot and polycyclic aromatic hydrocarbons (PAH). Their infrared spectra have been recorded by IR/UV ion dip spectroscopy using free electron laser radiation. The radicals were generated by flash pyrolysis from the corresponding nitrites and resonantly ionized via the D3 ← D0 transition around 310 nm. Mid-infrared spectra of the three xylyl isomers were recorded between 550 and 1700 cm-1 and are in excellent agreement with computations, provided that overtones and combination bands are included in the simulation. The results show that the three xylyl isomers can be distinguished by their infrared spectra and that no isomerization occurs in the pyrolysis reactor. The IR spectra obtained at m/z = 208 indicate that dimerization of xylyl radicals leads to substituted stilbenes, which has not been observed for benzyl.

There are data suggesting that intravenous dexamethasone has an effect on postoperative analgesia when given during single-shot spinal anaesthesia. However, the research literature is equivocal. We performed a systematic literature search followed by conventional meta-analysis (random effects model). We used trial sequential analysis to control for type-1 and -2 statistical errors. We also performed a leave-one-out meta-analysis for our primary outcome, the consumption of intravenous morphine in the first 24 postoperative hours. We applied the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system to rate the level of evidence. We obtained data from 1133 patients, reported in 17 trials. Reporting quality was high, with low risk of bias. Dexamethasone use was associated with a significant reduction in 24-h morphine consumption, the mean difference (95%CI) being -4.01 (-5.01 to -3.01) mg, 6 trials, 326 participants, I2 = 0%. Trial sequential analysis showed that there was firm evidence for the primary outcome, and leave-one-out meta-analysis showed that our result was not driven by one single trial. The GRADE evaluation showed a high level of evidence, suggesting that further studies are unlikely to alter the result. The time to first analgesic request (95%CI) was significantly prolonged by 86.62 (10.62-162.62) min, I2 = 93%, in the dexamethasone group. For other secondary outcomes including number of patients requiring rescue analgesia, or visual analogue scale pain scores, we found no evidence of a significant difference between the treatment arms. We report a high level of evidence that intravenous dexamethasone improves postoperative analgesia after spinal anaesthesia.

Peptide aggregation, the self-assembly of peptides into structured beta-sheet fibril structures, is driven by a combination of intra- and intermolecular interactions. Here, the interplay between intramolecular and formed inter-sheet hydrogen bonds and the effect of dispersion interactions on the formation of neutral, isolated, peptide dimers is studied by infrared action spectroscopy. Therefore, four different homo- and hetereogeneous dimers formed from three different alanine-based model peptides have been studied under controlled and isolated conditions. The peptides differ from one another in the presence and location of a UV chromophore containing cap on either the C- or N-terminus. Conformations of the monomers of the peptides direct the final dimer structure: strongly hydrogen bonded or folded structures result in weakly bound dimers. Here the intramolecular hydrogen bonds are favored over new intermolecular hydrogen bond interactions. In contrast, linearly folded monomers are the ideal template to form parallel beta-sheet type structures. The weak intramolecular hydrogen bonds present in the linear monomers are replaced by the stronger inter-sheet hydrogen bond interactions. The influence of π-π disperion interactions on the structure of the dimer is minimal, the phenyl rings have the tendency to fold away from the peptide backbone to favour intermolecular hydrogen bond interactions. Quantum chemical calculations confirm our experimental observations.

Esta nota explora algunos vínculos entre la gobernanza de desastres y las inteligencias colectivas vinculadas a la construcción y diseño de productos en ciudades del Sur Global, al tiempo que ofrece algunas reflexiones para futuras investigaciones. Las ideas presentadas en este trabajo son el resultado de una serie de mesas redondas ocurridas el 2021 entre un grupo de especialistas en el área de estudios sobre desastres e inteligencias colectivas. La metodología se basó en temas discutidos previamente y preguntas orientadoras para explorar tales vínculos: ¿Tienen las inteligencias colectivas el poder de transformar estructuras sociales superiores en el ámbito de la construcción y la gestión del riesgo?; ¿cómo puede la gobernanza (formal) de los desastres y la urbana tratar con las inteligencias colectivas? Los resultados fueron sistematizados y resumidos en este trabajo. Algunos resultados señalan la necesidad de conectar el desarrollo urbano, la gobernanza de desastres, las inteligencias colectivas y la producción arquitectónica para futuras investigaciones y prácticas. Soluciones urbanas oportunas y contextualizadas que maximicen la (re)utilización de los escasos recursos comunitarios podrían ser una buena alternativa para atender la creciente demanda de vivienda y nuevos productos que resuelvan problemas básicos y al mismo tiempo fortalezcan la resiliencia ante desastres.

Small cyclic peptides containing phenylalanine residues are prone to aggregate in the gas phase into highly hydrophobic chains. A combination of laser desorption, mass spectrometry and conformational selective IR-UV action spectroscopy allows us to obtain detailed structural insights into the formation processes of the cyclic l-phenylalanyl-l-phenylalanine dipeptide (named cyclo-FF) aggregates. The rigid properties of cyclo-FF result in highly resolved IR spectra for the smaller clusters (n ≤ 3) and corresponding conformational assignments. For the higher order clusters (n > 3) the spectra are less resolved, however the observed ratios, peak positions and trends in IR shifts are key to make predictions on their structural details. Whereas the mid-IR spectral region between 1000-1800 cm-1 turns out to be undiagnostic for these small aggregates and the 3 μm region only for specific calculated structures, the far-IR contains valuable information that allows for clear assignments.

Background: Nursing homes (NH) residents with COVID-19 can either be tested because of presence of core symptoms (fever, cough, dyspnea) (S-based) or because of transmission prevention (TP-based). We described the clinical presentation and course of COVID-19 in NH residents who were tested either because of presence of core symptoms (S-based) or because of transmission prevention (TP-based).Methods:. XXX (XXX), is a 1185-bed NH. All NH residents who underwent SARS-CoV-2 RT-PCR testing between March 16, 2020 and May 31, 2020 were included (n = 380) in this retrospective cohort study. Clinical symptoms, temperature and oxygen saturation were extracted from medical records, 7 days before testing up to 14 days after testing.Results: SARS-CoV-2 was confirmed in 81 (21%) residents. Of these 81, 36 (44%) residents were tested S-based and 45 (56%) residents were tested TP-based. Yet, CT-values did not differ between the groups. In the 7 days prior to the test the most common symptoms in both groups were: falling (32%), somnolence (25%) and fatigue (21%). Two days before the test, we observed a stronger decrease in oxygen saturation and an increase in temperature for the S-based group compared to the T-based group that remained up to 10 days after testing. Residents with in the S-based group were 2.5 times more likely to decease within 30 days than residents in the TP-based group (HR, 2.56; 95% 1.3 to 5.2). Even though, 73% of the T-based group did eventually developed core symptoms.Conclusions: Many NH residents with a positive PCR did not have core symptoms when tested but had other signs/symptoms in the week before the positive test. Testing policies should therefore be adjusted to prevent transmission. Daily measures of temperature and oxygen saturation can contribute to earlier detection.

ObjectivesInitially, for preventing COVID-19 transmission in long-term care facilities (LTCF) primarily rely on presence of core symptoms (fever, cough, dyspnea), but LTCF residents may also show an atypical course of a SARS-CoV-2 infection. We described the clinical presentation and course of COVID-19 in LTCF residents who were tested either because of presence of core symptoms (S-based) or because of transmission prevention (TP-based)DesignRetrospective cohort study.Setting and participantsAmsta (Amsterdam, The Netherlands), is a 1185-bed LTCF. All LTCF residents who underwent SARS-CoV-2 RT-PCR testing between March 16, 2020 and May 31, 2020 were included (n = 380).MeasuresClinical symptoms, temperature and oxygen saturation were extracted from medical records, 7 days before testing up to 14 days after testing.ResultsSARS-CoV-2 was confirmed in 81 (21%) residents. Of these 81, 36 (44%) residents were tested S-based and 45 (56%) residents were tested TP-based. Yet, CT-values did not differ between the groups. In the 7 days prior to the test the most common symptoms in both groups were: falling (32%), somnolence (25%) and fatigue (21%). Two days before the test, we observed a stronger decrease in oxygen saturation and an increase in temperature for the S-based group compared to the T-based group that remained up to 10 days after testing. Residents with in the S-based group were 2.5 times more likely to decease within 30 days than residents in the TP-based group (HR, 2.56; 95% 1.3 to 5.2). Even though, 73% of the T-based group did eventually developed core symptoms.Conclusion and implicationsMany LTCF residents with a positive PCR did not have core symptoms when tested but had other signs/symptoms in the week before the positive test. Testing policies should therefore be adjusted to prevent transmission. Daily measures of temperature and oxygen saturation can contribute to earlier detection.

COVID-19 has posed an unprecedented challenge to the international scientific community. Along with the disruption faced by most of the world's population, many researchers have felt an added pressure to understand, cure and mitigate the virus. In order to gain insight into what impact COVID-19 has had on the international scientific community, their work and the implications for science, we conducted a survey with our editors, reviewers and authors in May and June 2020. In one of the largest academic surveys ever conducted, 25,307 members of our academic community participated, representing diverse countries, roles, and areas of research.

This paper proposes the use of low-cost 3D printed Luneburg lenses as retroreflectors in microwave applications. Luneburg lenses have previously been associated with unnecessarily costly structures due to the stepped gradient index using multilayered spherical shells. Within the context of additive manufacturing, the gradient dielectric profile utilized in a Luneburg lens reduces the cost of fabrication, enabling a reevaluation of the use of the device in modern applications. In this paper, additively manufactured Luneburg lens retroreflector topologies which have a near omnidirectional response across the azimuthal plane are demonstrated, which aim to function in a similar fashion to traditional low-cost infrared-based retroreflectors spheres used in high resolution positioning systems, with the added ability to work in low-visibility conditions or in infrared-saturated environments, such as a sunny day. The retroreflective Luneburg lens radar cross section is measured and demonstrate basic positioning principles.

BACKGROUND: Intradural extramedullary spinal cord tumors (ID-EMSCT) make up 40% of all spinal neoplasms. Resection of these tumors is mostly conducted using intraoperative neuromonitoring (IONM). However, the literature shows heterogenous data on its added value for ID-EMSCT. The aim of this study is to define sensitivity and specificity of IONM in ID-EMSCT resection and to study possible correlations between preoperative, intraoperative, and postoperative variables and neurologic outcomes after ID-EMSCT resection.METHODS: Data of patients undergoing ID-EMSCT surgeries with IONM from January 2012 until July 2019 were examined. Using neurologic status 6 weeks and 1 year postoperatively, sensitivity and specificity for IONM were calculated. IONM test results and neurologic outcomes were paired to preoperative, intraoperative, and postoperative parameters.RESULTS: Data of 78 patients were analyzed. 6 weeks postoperatively, 14.10% of patients had worse neurologic status, decreasing to 9.84% 1 year postoperatively. Multimodal IONM showed a sensitivity of 0.73 (95% confidence interval [CI], 0.39-0.94) and a specificity of 0.78 (95% CI, 0.66-0.87) after 6 weeks, and a sensitivity of 1.00 (95% CI, 0.54-1.00) and a specificity of 0.71 (95% CI, 0.57-0.82) after 1 year.CONCLUSIONS: IONM yielded high to perfect sensitivity and high specificity. However, IONM signals did not always determine the extent of resection, and false-positive results did not always result in incomplete tumor resections, because of surgeons overruling IONM. Therefore, IONM cannot fully replace clinical judgment and other perioperative information.

Non-covalent interactions are rapidly gaining interest as they are often crucial in determining the properties of materials, and key to supramolecular chemistry and to biochemistry. Non-covalent Polycyclic Aromatic Hydrocarbon (PAH) complexes are in particular relevant to astrochemistry and combustion chemistry where they are involved in the initial steps of condensation and soot formation, respectively. Here, we investigated non-covalent π-π stacking and CH-π interactions in naphthalene and acenaphthene clusters using high resolution IR-UV spectroscopy in combination with quantum chemical calculations. We identified spectral shifts that occur upon complexation and thereby evaluated predicted potential energy surfaces. The results provide strong indications for a prevalent parallel naphthalene dimer, showing that π-π stacking interactions become significant for bicyclic and larger PAHs.

Non-covalent interactions are rapidly gaining interest as they are often crucial in determining the properties of materials, and key to supramolecular chemistry and to biochemistry. Non-covalent Polycyclic Aromatic Hydrocarbon (PAH) complexes are in particular relevant to astrochemistry and combustion chemistry where they are involved in the initial steps of condensation and soot formation, respectively. Here, we investigated non-covalent π-π stacking and CH-π interactions in naphthalene and acenaphthene clusters using high resolution IR-UV spectroscopy in combination with quantum chemical calculations. We identified spectral shifts that occur upon complexation and thereby evaluated predicted potential energy surfaces. The results provide strong indications for a prevalent parallel naphthalene dimer, showing that π-π stacking interactions become significant for bicyclic and larger PAHs.

A high-power digital transmitter (DTX) concept, targeting future low-cost, highly-integrated and energy-efficient mMIMO base stations, is presented. The proposed approach bridges the “historical” gap between low-voltage high-speed digital and high-voltage high-power RF devices. The resulting combination allows for a complete replacement of the traditional TX line-up, which includes signal-generation, up-conversion, and analog pre-drivers and power amplifier (PA), as such, facilitating drastic energy savings. The DTX principles are demonstrated by a dual TX line-up implemented in a dedicated $V_{T}$ -shifted LDMOS technology. Each 11-bit DTX line-up features 15 thermometer and 7 binary-weighted LDMOS output-stage segments, which are individually controlled by digital logic and high-speed drivers implemented in 40 nm CMOS technology. The realized DTX prototype exploits a 2.1 GHz centered class-BE output matching network and provides, at 20 V drain supply, 18.5 W (CW) output power with 66.7 % drain and 60.4 % system efficiencies. The suitability of the concept to handle modulated signals is demonstrated for a two-tone signal (Δ $f = 80$ kHz), yielding an 1M 3 < -51.4dBc and a 10MHz 256-QAM signal, achieving an ACLR of -46.1 dBc and 1.2 % EVM.

A metabolomics profiling approach was conducted to identify diagnostic biomarkers of PD from sebum, a non-invasively available biofluid. In this study, we used liquid chromatography-mass spectrometry (LC-MS) to analyse 274 samples from participants (80 drug naïve PD, 138 medicated PD and 56 well matched control subjects) and detected metabolites that could predict PD phenotype. Partial least squares-discriminant analysis (PLS-DA) models based on this sebum metabolome had correct classification rates of 70.4% and 69.7% to distinguish between drug naïve PD and medicated PD from control, respectively. Variable importance in projection (VIP) scores indicate compounds with significance belonged to sphingolipid, triacylglycerol and fatty acid/ester lipid classes. Pathway enrichment analysis showed alterations in lipid metabolism and mitochondrial dysfunction viz. the carnitine shuttle, sphingolipid metabolism and arachidonic acid metabolism. This study unveiled novel diagnostic sebum-based biomarkers for PD, and provides insight towards our current understanding of the pathogenesis of PD.

A metabolomics profiling approach was conducted to identify diagnostic biomarkers of PD from sebum, a non-invasively available biofluid. In this study, we used liquid chromatography-mass spectrometry (LC-MS) to analyse 274 samples from participants (80 drug naïve PD, 138 medicated PD and 56 well matched control subjects) and detected metabolites that could predict PD phenotype. Partial least squares-discriminant analysis (PLS-DA) models based on this sebum metabolome had correct classification rates of 70.4% and 69.7% to distinguish between drug naïve PD and medicated PD from control, respectively. Variable importance in projection (VIP) scores indicate compounds with significance belonged to sphingolipid, triacylglycerol and fatty acid/ester lipid classes. Pathway enrichment analysis showed alterations in lipid metabolism and mitochondrial dysfunction viz. the carnitine shuttle, sphingolipid metabolism and arachidonic acid metabolism. This study unveiled novel diagnostic sebum-based biomarkers for PD, and provides insight towards our current understanding of the pathogenesis of PD.

Avobenzone (AB) is a widely used UVA filter known to undergo irreversible photodegradation. Here, we investigate the detailed pathways by which AB photodegrades by applying UV laser-interfaced mass spectrometry to protonated AB ions. Gas-phase infrared multiple-photon dissociation (IRMPD) spectra obtained with the free electron laser for infrared experiments, FELIX, (600-1800 cm-1) are also presented to confirm the geometric structures. The UV gas-phase absorption spectrum (2.5-5 eV) of protonated AB contains bands that correspond to selective excitation of either the enol or diketo forms, allowing us to probe the resulting, tautomer-dependent photochemistry. Numerous photofragments (i.e. photodegradants) are directly identified for the first time, with m/z 135 and 161 dominating, and m/z 146 and 177 also appearing prominently. Analysis of the production spectra of these photofragments reveals that that strong enol to keto photoisomerism is occurring, and that protonation significantly disrupts the stability of the enol (UVA active) tautomer. Close comparison of fragment ion yields with the TDDFT-calculated absorption spectra give detailed information on the location and identity of the dissociative excited state surfaces, and thus provide new insight into the photodegradation pathways of avobenzone, and photoisomerisation of the wider class of β-diketone containing molecules.

We report infrared spectra of xylylene isomers in the gas phase, using free electron laser (FEL) radiation. All xylylenes were generated by flash pyrolysis. The IR spectra were obtained by monitoring the ion dip signal, using a IR/UV double resonance scheme. A gas phase IR spectrum of para‐xylylene was recorded, whereas ortho‐ and meta‐xylylene were found to partially rearrange to benzocyclobutene and styrene. Computations of the UV oscillator strength for all molecules were carried out and provde an explanation for the observation of the isomerization products., A gas phase IR spectrum of para‐xylylene was recorded by IR/UV ion dip spectroscopy. The molecule was generated by flash pyrolysis. Ortho‐ and meta‐xylylene partially rearrange to benzocyclobutene and styrene. Their detection can be explained by the oscillator strength of the UV transition.

The thermal reactions of [CoX]+ (X = CN, F, Cl, Br, O, OH) with carbon dioxide have been investigated experimentally and theoretically by using electrospray ionization mass spectrometry (ESI-MS) and density functional theory. Surprisingly, in contrast to the complete inertness of [CoX]+ (X = F, Cl, Br, O, OH) toward carbon dioxide, [Co(CN)]+ activates carbon dioxide to form the elusive [NCCO2Co]+ ion in the gas phase. Mechanistic investigation into this ligand-controlled CO2 activation via C_C bond formation, mediated by a first-row late transition-metal complex, reveals that the inertness of [CoX]+ (X = F, Cl, Br, O, OH) is due to kinetic barriers located above the entrance asymptote. The exception is the [Co(CN)]+/CO2 couple, for which the thermal C–C bond formation is both thermochemically and kinetically accessible. Interestingly, a cyanoformate ligand is most likely also formed in the reaction of [Fe(CN)]+ with CO2; cyanoformate formation had been suggested earlier as a protective mechanism to prevent cyanide complexation to the iron-containing active site of the enzyme ACC oxidase (Murphy et al., in Science 344:75–78, 2014).

Purpose To determine the outcome of out-of-hospital (OOH) cardiopulmonary resuscitation (CPR) and the advanced life support (ALS) procedures provided in pediatrics by the Rotterdam Helicopter Emergency Medical Service (HEMS) Methods Retrospective evaluation of all pediatric (0–17 years) OOH cardiopulmonary arrests within a 6-year period and attended by the Rotterdam HEMS team. Results There were 201 OOH CPRs from October 2008 until October 2014. Endotracheal intubation was performed in 164 cases and done by HEMS in 104 patients (63%), intraosseous/intravenous cannulation 43/27 times, and additional medication given by HEMS in 70 patients (35%). The overall survival rate for OOH CPR was 15%, but in trauma was low. Twenty-seven of the 29 pediatric patients who survived until discharge are neurological well. Although the Dutch nationwide ambulance protocol states intubation, intravenous, or intraosseal excess and medication, in many patients, only HEMS provided additional ALS care. Conclusion The HEMS brings essential medical expertise in the field not provided by regular emergency medical service. HEMS provide a significant quantity of procedures, obviously needed by the OOH CPR of a pediatric patient.

Ortho-benzyne, a Kekule-type biradical is considered to be a key intermediate in the formation of polycyclic aromatic hydrocarbons (PAH) and soot. In the present work we study the ortho-benzyne self-reactions in a hot micro-reactor and identify the high-temperature products by IR/UV spectroscopy and by photoion mass-selected threshold photoelectron spectroscopy (ms-TPES) in a free jet. Ms-TPES confirms formation of ortho-benzyne as generated from benzocyclobutendione, as well as benzene, biphenylene, diacetylene and acetylene, originating from the reaction o-C6H4  HCC-CCH + C2H2 , and CH3. PAH molecules like naphthalene, 2-ethynylnaphthalene, fluorene, phenanthrene and triphenylene are identified based on their IR/UV spectra. By comparison with recent computations their formation starting from ortho-benzyne can be readily understood and supports the importance of the biradical addition (1,4-cycloaddition followed by fargmenation) pathway to PAH molecules, recently proposed by Comandini et al.