Insight into the direct conversion of methane to methanol on modified ZIF-204 from the perspective of DFT-based calculations.

Direct oxidation of methane over oxo-doped ZIF-204, a bio-mimetic metal-organic framework, is investigated under first-principles calculations based on density functional theory. In the pristine ZIF-204, the tetrahedral methane molecule anchors to an open monocopper site via the so-called η2 configuration with a physisorption energy of 0.24 eV. This weak binding arises from an electrostatic interaction between the negative charge of carbon in the methane molecule and the positive Cu2+ cation in the framework. In the modified ZIF-204, the doped oxo species is stabilized at the axial position of a CuN4-base square pyramid at a distance of 2.06 Å. The dative covalent bond between Cu and oxo is responsible for the formation energy of 1.06 eV. With the presence of the oxo group, the presenting of electrons in the O_pz orbital accounts for the adsorption of methane via hydrogen bonding with an adsorption energy of 0.30 eV. The methane oxidation can occur via either a concerted direct oxo insertion mechanism or a hydrogen-atom abstraction radical rebound mechanism. Calculations on transition-state barriers show that reactions via the concerted direct oxo insertion mechanism can happen without energy barriers. Concerning the hydrogen-atom abstraction radical rebound mechanism, the C-H bond dissociation of the CH4 molecule is barrierless, but the C-O bond recombination to form the CH3OH molecule occurs through a low barrier of 0.16 eV. These predictions suggest the modified ZIF-204 is a promising catalyst for methane oxidization.

Skull base infections, their complications, and management.

OBJECTIVE: Our review aims to summarize the current literature on skull base infections (SBIs) and retrospectively analyze any such cases encountered at our institution. DESIGN: A literature search was conducted using online databases PubMed, MEDLINE, and ResearchGate with the terms "skull base osteomyelitis," "temporal bone osteomyelitis," "skull base infections," "necrotizing otitis media," and "SBO". References from the resulting manuscripts were reviewed for relevant articles. A search of our electronic health records using the same key terms was also performed to identify patients with a tissue biopsy-confirmed diagnosis of skull base infections. Patients with an indeterminate diagnosis or inaccessible/poor imaging were excluded. SETTING: A level one trauma and major tertiary academic medical center. PARTICIPANTS: All patients treated at the University of California Davis Health System with a confirmed diagnosis of skull base infections from January 2005 to November 2020. MAIN OUTCOME MEASURES: Imaging results, symptoms, treatment, morbidity, and mortality. RESULTS: Our literature search yielded 59 articles ranging from 1982 to 2021. A retrospective search of our electronic health records identified two cases of skull base infections. CONCLUSION: Skull base infections have no pathognomonic findings. A multimodal approach with computed tomography (CT), magnetic resonance imaging (MRI), and nuclear medicine is necessary to characterize the disease process in addition to a biopsy for definitive diagnosis. Other diagnoses can mimic SBI on imaging, such as nasopharyngeal carcinoma and inflammatory pseudotumor. Culture-guided antimicrobial treatment and surgery are mainstay therapies. Other adjuvant strategies currently lack the robust evidence necessary to characterize their risks and benefits.

Neuraxial anesthesia and pain control for pediatric burn patients receiving excision and split-thickness skin grafts-A retrospective case series.

BACKGROUND: Postoperative pain management in pediatric burn patients requiring excision and split-thickness skin grafts remains largely under-studied. ICU care is often necessary due to the level of sedation and amount of opioids required to achieve adequate pain control. AIMS: Our case series aimed to describe a pain management strategy using neuraxial anesthesia intraoperatively. Primary outcomes include pain scores, postoperative opioid consumption, and adverse events. METHODS: A retrospective chart review was performed on a total of 61 patients who received intraoperative neuraxial anesthesia for split-thickness skin grafting between January 1st, 2017 and June 1st, 2018. Patient demographics, operating room data, and subsequent hospital course was extracted from their electronic medical record and plotted using R Studio statistical software. RESULTS: The overwhelming majority of patients received single-shot spinals with both local anesthetic and either morphine or hydromorphone. Average pain scores were 1 out of 10 with standard deviation of 1.6 in the immediate postoperative period and decreased over the next 72 h. Oral morphine equivalents consumed did not exceed 0.61 ME/kg/day. The most common adverse reaction was pruritus. CONCLUSIONS: Spinal anesthesia was most commonly used for split-thickness skin grafting in the pediatric burn population and provides excellent analgesia for patients' immediate postoperative course, including their initial dressing changes, with minimal risk for complications. Pain was well-controlled in all subgroups indicating that this strategy can be used flexibly in a variety of pediatric burn patients.

Quantum Dot Sensitized Solar Cell: Photoanodes, Counter Electrodes, and Electrolytes.

In this study, we provide the reader with an overview of quantum dot application in solar cells to replace dye molecules, where the quantum dots play a key role in photon absorption and excited charge generation in the device. The brief shows the types of quantum dot sensitized solar cells and presents the obtained results of them for each type of cell, and provides the advantages and disadvantages. Lastly, methods are proposed to improve the efficiency performance in the next researching.

High human disturbance decreases individual variability in skink escape behavior.

Animals living around people may modify their antipredator behavior as a function of proximity to humans, and this response has profound implications for whether or not a population can coexist with humans. We asked whether inland blue-tailed skinks Emoia impar modified their individual antipredator behavior as a function of differential exposure to humans. We conducted multiple consecutive flushes and recorded 2 measures of antipredator response: flight initiation distance (FID), the distance from a threatening stimulus at which an individual flees, and distance fled, the distance an individual fled after a flush. We used a multiple model comparison approach to quantify variation in individual escape behavior across multiple approaches and to test for differences in between-individual variation among populations. We found that individuals tolerated closer approach and fled shorter distances at locations with relatively less human disturbance than at locations with medium and high human disturbance, respectively. In addition, skinks living at high human disturbance sites had less variable FIDs than at low human disturbance sites. Two theories may explain these results. Selection against less favorable phenotypes has reduced behavioral variation in urban habitats and behavioral plasticity allows individuals to flexibly adjust their behavioral patterns in response to human disturbance. These results highlight the importance of studying variation within populations, at the individual level, which may better elucidate the impact that human disturbance has on the behavioral composition of populations.