Risk factors for Bakri balloon tamponade failure in the management of postpartum hemorrhage.

OBJECTIVE: To predict risk factors for Bakri balloon tamponade (BBT) failure in the management of postpartum hemorrhage (PPH). METHODS: The data of 599 patients who underwent BBT were retrospectively analyzed from January 1, 2017 to December 31, 2021 in a tertiary hospital in Shanghai, East China. The patients were divided into the failure group and the success group. Failure was defined as the inability to control bleeding, which required surgical interventions. Maternal characteristics, PPH characteristics, PPH management approaches, and maternal complications were compared between the groups. The independent predictors of BBT failure were analyzed by logistic regression analysis. RESULTS: The overall success rate of BBT was 83.0% (497/599). The blood loss before and after balloon insertion in the failure group was significantly greater than that in the success group. Of the 102 failures, B-Lynch suture was performed in one patient, uterine artery embolization was performed in 99 patients (with one failure), and total hysterectomy was performed in three patients. Some risk factors, including twin gestation (odds ratio [OR] 9.68), placenta accreta spectrum with/without placenta previa (OR 4.45), estimated blood loss at least 1135 ml at balloon insertion (OR 3.35), multiparous (OR 2.72), and in vitro fertilization-embryo transfer (OR 2.00) were strongly associated with BBT failure. CONCLUSION: BBT seemed to be a less effective tool in the management of PPH due to placenta accreta spectrum with/without placenta previa and twin gestation.

Engineering Photomechanical Molecular Crystals to Achieve Extraordinary Expansion Based on Solid-State [2 + 2] Photocycloaddition.

Photomechanical molecular crystals are promising candidates for photoactuators and can potentially be implemented as smart materials in various fields. Here, we synthesized a new molecular crystal, (E)-3-(naphthalen-1-yl)acrylaldehyde malononitrile ((E)-NAAM), that can undergo a solid-state [2 + 2] photocycloaddition reaction under visible light (≥400 nm) illumination. (E)-NAAM microcrystals containing symmetric twinned sealed cavities were prepared using a surfactant-mediated crystal seeded growth method. When exposed to light, the hollow microcrystals exhibited robust photomechanical motions, including bending and dramatic directional expansion of up to 43.1% elongation of the original crystal length before fragmentation due to the photosalient effect. The sealed cavities inside the microcrystals could store different aqueous dye solutions for approximately one month and release the solutions instantly upon light irradiation. A unique slow-fast-slow crystal elongation kinematic process was observed, suggesting significant molecular rearrangements during the illumination period, leading to an average anisotropic crystal elongation of 37.0% (±3.8%). The significant molecular structure and geometry changes accompanying the photocycloaddition reaction, which propels photochemistry to nearly 100% completion, also facilitate photomechanical crystal expansion. Our results provide a possible way to rationally design molecular structures and engineer crystal morphologies to promote more interesting photomechanical behaviors.

Acoustic features as novel predictors of difficult laryngoscopy in orthognathic surgery: an observational study.

BACKGROUND: The evaluation of the difficult intubation is an important process before anaesthesia. The unanticipated difficult intubation is associated with morbidity and mortality. This study aimed to determine whether acoustic features are valuable as an alternative method to predict difficult laryngoscopy (DL) in patients scheduled to undergo orthognathic surgery. METHODS: This study included 225 adult patients who were undergoing elective orthognathic surgery under general anaesthesia with tracheal intubation. Preoperatively, clinical airway evaluation was performed, and the acoustic data were collected. Twelve phonemes {[a], [o], [e], [i], [u], [ü], [ci], [qi], [chi], [le], [ke], and [en]} were recorded, and their formants (f1-f4) and bandwidths (bw1-bw4) were extracted. Difficult laryngoscopy was defined as direct laryngoscopy with a Cormack-Lehane grade of 3 or 4. Univariate and multivariate logistic regression analyses were used to examine the associations between acoustic features and DL. RESULTS: Difficult laryngoscopy was reported in 59/225 (26.2%) patients. The area under the curve (AUC) of the backward stepwise model including en_f2 [odds ratio (OR), 0.996; 95% confidence interval (CI), 0.994-0.999; P=0.006], ci_bw4 (OR, 0.997; 95% CI, 0.993-1.000; P=0.057), qi_bw4 (OR, 0.996; 95% CI, 0.993-0.999; P=0.017), le_f3 (OR, 0.998; 95% CI, 0.996-1.000; P=0.079), o_bw4 (OR, 1.001; 95% CI, 1.000-1.003; P=0.014), chi_f4 (OR, 1.003; 95% CI, 1.000-1.005; P=0.041), a_bw4 (OR, 0.999; 95% CI, 0.998-1.000; P=0.078) attained a value of 0.761 in the training set, but a value of 0.709 in the testing set. The sensitivity and specificity of the model in the testing set are 86.7% and 63.0%, respectively. CONCLUSIONS: Acoustic features may be considered as useful predictors of DL during orthognathic surgery.

Motorized Macrocycle: A Photo-responsive Host with Switchable and Stereoselective Guest Recognition.

Designing photo-responsive host-guest systems can provide versatile supramolecular tools for constructing smart systems and materials. We designed photo-responsive macrocyclic hosts, modulated by light-driven molecular rotary motors enabling switchable chiral guest recognition. The intramolecular cyclization of the two arms of a first-generation molecular motor with flexible oligoethylene glycol chains of different lengths resulted in crown-ether-like macrocycles with intrinsic motor function. The octaethylene glycol linkage enables the successful unidirectional rotation of molecular motors, simultaneously allowing the 1:1 host-guest interaction with ammonium salt guests. The binding affinity and stereoselectivity of the motorized macrocycle can be reversibly modulated, owing to the multi-state light-driven switching of geometry and helicity of the molecular motors. This approach provides an attractive strategy to construct stimuli-responsive host-guest systems and dynamic materials.

Color-tunable single-fluorophore supramolecular system with assembly-encoded emission.

Regulating the fluorescent properties of organic small molecules in a controlled and dynamic manner has been a fundamental research goal. Although several strategies have been exploited, realizing multi-color molecular emission from a single fluorophore remains challenging. Herein, we demonstrate an emissive system by combining pyrene fluorophore and acylhydrazone units, which can generate multi-color switchable fluorescent emissions at different assembled states. Two kinds of supramolecular tools, amphiphilic self-assembly and γ-cyclodextrin mediated host-guest recognition, are used to manipulate the intermolecular aromatic stacking distances, resulting in the tunable fluorescent emission ranging from blue to yellow, including a pure white-light emission. Moreover, an external chemical signal, amylase, is introduced to control the assembly states of the system on a time scale, generating a distinct dynamic emission system. The dynamic properties of this multi-color fluorescent system can be also enabled in a hydrogel network, exhibiting a promising potential for intelligent fluorescent materials.

Towards a hexa-branched [7]rotaxane from a [3]rotaxane via a [2+2+2] alkyne cyclotrimerization process.

A facile synthesis methodology to obtain a crown ether-based hexa-branched [7]rotaxane, has been achieved by using Co-catalyzed [2+2+2] alkyne cyclotrimerization from a [3]rotaxane. The [2+2+2] alkyne cyclotrimerization process, which requires only 10 mol% of Co2(CO)8 as a catalyst and affords an efficient production of target rotaxanes, represents a new strategy for the construction of highly complicated dendritic rotaxanes.

[Molecular mechanisms of recursive splicing events in long introns of eukaryotes].

Recursive splicing refers to the biological process that long introns are removed in multiple steps during pre-mRNA splicing. In comparison to large introns (>10 kb), most introns in higher eukaryotic genomes are removed in one step during transcription. Previous studies have revealed that recursive splicing events play important roles in many biological processes, including the pathogenesis and development of diseases. In recent years, more researchers have focused on recursive splicing events and found that recursive splicing occurs in Drosophila and many other vertebrates. Multiple recursive splicing sites have been predicted by different bioinformatics methods and verified by experiments. Current researches focus on the process of recursive splicing, recursive splicing site recognition and its influence on biological processes. In this review, we summarize the molecular mechanism of recursive splicing events in eukaryotic genomes and the present development in this field, aiming to lay the basis for further understanding of the mechanisms of RNA splicing.

Bistable [2]rotaxane encoding an orthogonally tunable fluorescent molecular system including white-light emission.

Orthogonally tunable multicolor fluorescence including white-light emission was achieved using a dual-component molecular system. Under external acid/base stimuli, we were able to change the fluorescence of a mixture of two fluorescent molecular switches in an orthogonal and reversible manner, hence generate emission of multiple colors from blue to yellow, including white light (CIE (0.29, 0.34)).

Dynamic Self-Assembly of Gold/Polymer Nanocomposites: pH-Encoded Switching between 1D Nanowires and 3D Nanosponges.

The design of tunable dynamic self-assembly of nanoparticles with switchable assembled dimensions and morphologies is a challenging goal whose realization is vital for the evolution of smart nanomaterials. Herein, we report on chitosan polymer as an effective supramolecular "glue" for aldehyde-modified Au nanoparticles to reversibly modulate the states of self-assembled nanocomposites. By simultaneous integration of dynamic covalent Schiff base interactions and noncovalent hydrogen bonds, the chitosan/Au nanocomposites could reversibly transform their assembled morphologies from one-dimensional nanowires to three-dimensional nanosponges in response to the variation of pH value. Moreover, the obtained nanosponges could be used as an efficient pH-controlled cargo release system.

A novel 22-bp deletion mutation in a Chinese family with X-linked hypohidrotic ectodermal dysplasia.

X-linked hypohidrotic ectodermal dysplasia (XLHED) is the most common form of the ectodermal dysplasias characterized by an abnormal development of eccrine sweat glands, hair and teeth. Pathogenic mutations in the ED1 gene have been identified. In this family, a 22-bp deletion mutation of exon 8 in the ED1 gene was found in the affected members but not in the healthy individuals and 100 unrelated controls. We add new variant to the knowledge of ED1 mutations in XLHED.