Phase Transition Control in Molecular Solids via Complementarity of Hydrogen-Bond Strength.

Phase transitions in molecular solids involve synergistic changes in chemical and electronic structures, leading to diversification in physical and chemical properties. Despite the pivotal role of hydrogen bonds (H-bonds) in many phase-transition materials, it is rare and challenging to chemically regulate the dynamics and to elucidate the structure-property relationship. Here, four high-spin CoII com-pounds were isolated and systematically investigated by modifying the ligand terminal groups (X = S, Se) and substituents (Y = Cl, Br). S-Cl and Se-Br undergo a reversible structural phase transition near room temperature, triggering the rotation of 15-crown-5 guests and the swing between syn- and anti-conformation of NCX- ligands, accompanied by switchable magnetism. Conversely, S-Br and Se-Cl retain stability in ordered and disordered phases, respectively. H-bonds geometric analysis and ab initio calculations reveal that the electronegativity of X and Y affects the strength of NY-ap-H···X interactions. Entropy-driven structural phase transitions occur when the H-bond strength is appropriate; otherwise, the phase stays unchanged if it is too strong or weak. This work highlights a phase transition driven by H-bond strength complementarity - pairing strong acceptor with weak donor and vice versa, which offers a straightforward and effective approach for designing phase-transition molecular solids from a chemical perspective.

A Novel Method to Classify the Responses of Genioglossus to Negative Pressure in OSA Patients.

OBJECTIVE: This study aims to develop a novel method to classify different genioglossus (GG) responses to upper airway (UA) negative pressure in obstructive sleep apnea (OSA) patients. STUDY DESIGN: A single-center, prospective, cohort study. SETTING: Sleep Medical Center. METHODS: Patients with OSA underwent drug-induced sleep endoscopy with synchronous genioglossus electromyography (ggEMG) and UA pressure monitoring. In spontaneous obstructive apnea events, the value of epiglottis negative pressure at the end of inspiration (Pepi ) and corresponding peak phasic ggEMG were recorded as pairing data for linear regression analysis to classify GG response modes: peak phasic ggEMG-Pepi linear mode (P < .05) were classified as group 1; others (P ≥ .05) were classified as group 2. Using nasopharyngeal tube (NPT) to reopen the palatopharyngeal cavity for comparing the improvement between the OSA patients with different GG response modes. RESULTS: Sixty subjects were analyzed for GG response modes: 22 patients were in group 1 (r2 = 0.233-0.867), and 38 patients were in group 2. The proportion of partial (63.16% vs 59.09%) or complete (36.84% vs 22.73%) collapse rate of the tongue base in group 2 was significantly higher (χ2 = 7.823, P = .020). The improvement of the apnea-hypopnea index after NPT placement in group 2 was significantly lower than in group 1 (59.09% vs 31.58%, χ2 = 4.339, P = .037). CONCLUSION: This novel method is advantageous for distinguishing OSA patients with different GG response abilities to UA negative pressure, whose GG responses conforming to peak phasic ggEMG-Pepi linear mode might be more suitable for palatopharyngeal surgery.

Baseline gut microbiome features prior to SARS-CoV-2 infection are associated with host symptoms in and post COVID-19.

The human gut microbiome varies substantially across individuals and populations and differentially tames our immunity at steady-state. Hence, we hypothesize that the large heterogeneity of gut microbiomes at steady-state may shape our baseline immunity differentially, and then mediate discrepant immune responses and symptoms when one encounters a viral infection, such as SARS-CoV-2 infection. To validate this hypothesis, we conducted an exploratory, longitudinal microbiome-COVID-19 study involving homogenous young participants from two geographically different regions in China. Subjects were recruited and sampled of fecal specimens before the 3-week surge window of COVID-19 (between December 11 and December 31, 2022) in China, and then were followed up for assessment of COVID-19 and post-COVID-19 manifestations. Our data showed that the baseline gut microbiome composition was intricately associated with different COVID-19 manifestations, particularly gastrointestinal involvement and post-COVID-19 lingering symptoms, in both an individual- and population-dependent manner. Our study intriguingly for the first time highlight that the gut microbiome at steady-state may prepare us differentially for weathering a respiratory viral infection.

Reversible Switchability of Magnetic Anisotropy and Magnetodielectric Effect Induced by Intermolecular Motion.

Introducing magnetic switchability into artificial molecular machines is fascinating for precise control of magnetism via external stimuli. Herein, a field-induced CoII single-molecule magnet was found to exhibit the reversible switch of Jahn-Teller distortion near room temperature, along with thermal conformational motion of the 18-crown-6 rotor, which pulls the coordinated H2 O to rotate through intermolecular hydrogen bonds and triggers a single-crystal-to-single-crystal phase transition with Twarm =282 K and Tcool =276 K. Interestingly, the molecular magnetic anisotropy probed by single-crystal angular-resolved magnetometry revealed the reorientation of easy axis by 14.6°. Moreover, ON/OFF negative magnetodielectric effects were respectively observed in the high-/low-temperature phase, which manifests the spin-lattice interaction in the high-temperature phase could be stronger, in accompanied by the hydrogen bonding between the rotating 18-crown-6 and the coordinated H2 O.

Application of drug-induced sleep endoscopy in predicting the outcomes of velopharyngeal surgery in adult patients with Friedman stage II and III obstructive sleep apnea syndrome.

Objective: This study aimed to evaluate the predictive value of drug-induced sleep endoscopy (DISE) for the outcomes of velopharyngeal surgery in adult patients with Friedman stage II and III obstructive sleep apnea syndrome (OSAS). Methods: A total of 39 male OSAS patients with Friedman stage II and III were retrospectively analyzed. Subjects with an apnea-hypopnea index (AHI) > 5 events/h indicated by polysomnography (PSG) and typical symptoms, such as snoring, sleep apnea, and daytime sleepiness, were included in this study. All these patients underwent pre-operative DISE examinations and were treated by velopharyngeal surgery and evaluated by velum, oropharynx, tongue base, and epiglottis (VOTE) scoring system. Clinical, polysomnographic parameters (e.g., hypopnea, apnea, AHI, lowest oxygen saturation, etc.), cephalometric variables, and DISE findings were evaluated. The treatment outcomes were assessed by polysomnography at least 6 months after surgery. Results: All 39 patients showed complete velopharyngeal airway collapses during pre-operative DISE examinations. After surgery, the AHI was significantly improved from 50.2 ± 21.6 to 19.8 ± 19 events/h (P < 0.05). There were 23 responders (59.0%) and 16 non-responders (41.0%). The glossopharyngeal airway collapse degree (GA-CD) was significantly different between responders and non-responders (P < 0.05). The velopharyngeal airway collapse pattern (VA-CP) and GA-CD were independently predictive of treatment outcomes (both P < 0.05). Patients with non-lateral VA-CP and grade II GA-CD (collapse degree > 50%) had a significantly lower surgical success rate than those without (P < 0.05). Conclusion: The VA-CP and GA-CD in DISE examination are valuable for predicting the treatment outcomes of velopharyngeal surgery in patients with Friedman stage II and III OSAS. Patients with lateral VA-CP and grade I GA-CD are appropriate candidates for velopharyngeal surgery.

Analysis of the myoelectric characteristics of genioglossus in REM sleep and its improvement by CPAP treatment in OSA patients.

OBJECTIVES: To reveal the characteristics of genioglossus (GG) activation in moderate and severe obstructive sleep apnea (OSA) patients during rapid eye movement (REM) sleep compared with non-rapid eye movement (NREM) sleep and to determine whether continuous positive airway pressure (CPAP) could improve GG activation in OSA patients during sleep. METHODS: All subjects underwent polysomnography (PSG) with synchronous GG electromyography (GGEMG) recording with intra-oral surface electrodes at baseline on the first night. Only those subjects diagnosed with moderate and severe OSA were included and were manually titrated with CPAP to achieve a therapeutic pressure (Pt) with GGEMG recording on the second night. RESULTS: Nine OSA patients and six normal controls were analyzed in this study. The tonic GGEMG was higher in OSA patients during wakefulness (p = 0.003) and NREM sleep (p = 0.015), but it was not higher in REM sleep (p = 0.862). The average phasic activity of OSA patients was significantly higher in all stages, including wakefulness (p = 0.007), NREM sleep (p = 0.005), and REM sleep (p = 0.021). The peak phasic GGEMG was not different in wakefulness compared with normal controls (p = 0.240), but it was higher in OSA patients in NREM sleep (p = 0.001) and REM sleep (p = 0.021), and it was significantly reduced by using CPAP during sleep (NREM sleep: p = 0.027; REM sleep: p = 0.001). CONCLUSIONS: Our results demonstrate that GG activation during NREM and REM sleep is associated with component differences. The tonic component of GGEMG exhibited less of a compensatory increase compared with the phasic component in REM sleep, suggesting that it may be one of the pathological mechanisms of UA collapsibility in REM sleep. In addition, treatment with CPAP can normalize GGEMG activity and mostly reduced the peak phasic GGEMG during sleep.