Enantioselective Syntheses of 3,4-Dihydropyrans Employing Isochalcogenourea-Catalyzed Formal (4+2)-Cycloadditions of Allenoates.

We herein successfully demonstrate the use of chiral isochalcogenoureas as Lewis Base catalysts for a variety of (4+2)-cycloaddition reactions of allenoates and different Michael acceptors. In all cases the same structural key-motive, a dihydropyran with a (Z)-configurated exocyclic double bond could be accessed as the major regio- and diastereoisomer in an enantioselective manner. Furthermore, these chiral dihydropyrans were successfully engaged in different follow-up transformations.

Important Counteranion Effect on Adsorption Efficacity of Hydrogen Sulfide by Silver(I)-Dithione Coordination Polymers.

Four new coordination polymers (CPs) have been prepared and evaluated for their efficacy in adsorbing hydrogen sulfide. The reactions of the structurally flexible assembling dithione ligand, L, with different silver(I) salts lead to four new metal-organic coordination architectures (CPs I, III, V, and VIII) exhibiting either one- or two-dimensional networks. CP I, 2D-[(Ag2Cl2)L]n, exhibits a linear series of rhomboid (S)2Ag(µ2-Cl)2Ag(S)2 secondary building units (SBUs) where S is one of the thione functions of L, altogether forming a 2D-network. CP III, 2D-[(AgI)L]n, is built upon parallel staircase-shaped 1D-[Ag2(µ3-I)2]n SBUs bridged by S atoms of L that form a 2D-grid. CP V, 2D-[(AgL)(NO3)]n, presents parallel 1D-folded S-shaped [AgL]n+ chains linked by strong argentophilic Ag···Ag interactions, forming a 2D-scaffolding. CP VIII, 1D-[(Ag2L3)(Cr2O7)]n, shows 1D-zigzag [{Ag(η2-µ2,η-µ,µ-L)}2]n2n+ chains accompanied by Cr2O72- counteranions. The adsorption isotherms of H2S gas by these new CPs were examined and compared to those of related CPs [(Ag2Br2)L]n (II), [(AgCN)4L]n (IV), [(Ag2L)(CF3SO3)2]n (VI), and [(Ag2L)(NO3)(ClO4)]n (VII). Among the tested polymers, the 3D-CP IV featuring cyanide anions exhibits the highest adsorption capacity of the CPs studied in this work. In order to determine the reason for this marked difference, density functional theory (DFT) computations were used. All in all, it turns out that the electrostatic interactions (CN-···H-SH) are significantly stronger than the O-···H-SH ones. This investigation provides a valuable conceptual tool for other designs of CPs and MOFs having the purpose of capturing toxic gases.

Revisiting Hafner's Azapentalenes: The Chemistry of 1,3-Bis(dimethylamino)-2-azapentalene.

Stable azaheterocyclic derivatives of pentalene have been reported by the group of Hafner in the 1970s. However, these structures remained of low interest until recently, when they started to be investigated in the context of organic light-emitting diodes' (OLEDs') development. Herein, we revisit the synthesis of stable azapentalene derivative 1,3-bis(dimethylamino)-2-azapentalene and further explore its properties both computationally and experimentally. Beyond the reproduction and optimization of some previously reported transformations, such as formylation and amine substitution, the available scope of reactions was expanded with azo-coupling, selective halogenations, and cross-coupling reactions.

Lactone Enolates of Isochroman-3-ones and 2-Coumaranones: Quantification of Their Nucleophilicity in DMSO and Conjugate Additions to Chalcones.

Owing to stereoelectronic effects, lactones often deviate in reactivity from their open-chain ester analogues as demonstrated by the CH acidity (in DMSO) of 3-isochromanone (pKa = 18.8) and 2-coumaranone (pKa = 13.5), which is higher than that of ethyl phenylacetate (pKa = 22.6). We have now characterized the reactivity of the lactone enolates derived from 3-isochromanone and 2-coumaranone by following the kinetics of their Michael reactions with p-quinone methides and arylidenemalonates (reference electrophiles) in DMSO at 20 °C. Evaluation of the experimentally determined second-order rate constants k2 by the Mayr-Patz equation, lg k2 = sN(N + E), furnished the nucleophilicity parameters N (and sN) of the lactone enolates. By localizing their position on the Mayr nucleophilicity scale, the scope of their electrophilic reaction partners becomes predictable, and we demonstrate a novel catalytic methodology for a series of carbon-carbon bond-forming reactions of lactone enolates with chalcones under phase transfer conditions in toluene.

Chiral Isochalcogenourea-Catalysed Enantioselective (4+2) Cycloadditions of Allenoates.

Allenoates are versatile building blocks which are primarily activated and controlled using chiral tert. phosphine and tert. amine Lewis bases. We herein report the first example of allenoate activation by using chiral isochalcogenoureas (IChU) for formal (4+2) cycloaddition reactions. Compared to established phosphine and amine catalysis, the use of these easily available Lewis bases enables new stereoselective reaction pathways proceeding with high enantioselectivities, diastereoselectivities, and in good yields. In addition, the factors governing enantioselectivity and the origin of the observed differences compared to other commonly used Lewis bases are explained.

The Association between Acupuncture Therapy and the Risk of Disability Development in Dementia Patients: A Nationwide Cohort Study.

Purpose: Disability is the comorbidity of dementia for which there is no available preventive measure. The aim of this study was to investigate the association between acupuncture treatment and the risk of disability development in dementia patients. Patients and Methods: A cohort study was performed using a nationwide health database in Taiwan. The included dementia patients were divided into acupuncture and non-acupuncture cohorts based on whether they received acupuncture treatment during the follow-up period. The variables in the two cohorts were controlled by 1:1 propensity-score matching. The difference in disability development in dementia patients between the acupuncture and non-acupuncture cohorts was also analyzed. Subgroup analyses were performed using socioeconomic variables, comorbidities and anti-dementia agents (donepezil, rivastigmine, galantamine and memantine) used for dementia treatment. Results: A total of 9,760 dementia patients met our inclusion criteria, and patients were divided into an equal number (n=2,422) of acupuncture and non-acupuncture groups, respectively, after 1:1 propensity-score matching. The dementia patients had a lower risk of disability development after acupuncture treatment than those who did not receive acupuncture treatment (adjusted hazard ratio 0.65, 95% confidence interval 0.60-0.70, p < 0.001). The results were independent of basic variables or comorbidities in the two cohorts. Patients who did not use anti-dementia agents had a lower risk of developing disability after receiving acupuncture intervention than those who used anti-dementia agents. Conclusion: Our results revealed the relationship between acupuncture intervention and decreased risk of developing disability in dementia patients. The results are useful for dementia treatment, trial design and further planning of care programs.

An Exploration of Substituent Effects on the Photophysical Properties of Monobenzopentalenes.

Monobenzopentalenes have received moderate attention compared to dibenzopentalenes, yet their accessibility as stable, non-symmetric structures with diverse substituents could be interesting for materials applications, including molecular photonics. Recently, monobenzopentalene was considered computationally as a potential chromophore for singlet fission (SF) photovoltaics. To advance this compound class towards photonics applications, the excited state energetics must be characterized, computationally and experimentally. In this report we synthesized a series of stable substituted monobenzopentalenes and provided the first experimental exploration of their photophysical properties. Structural and opto-electronic characterization revealed that all derivatives showed 1H NMR shifts in the olefinic region, bond length alternation in the pentalene unit, low-intensity absorptions reflecting the ground-state antiaromatic character and in turn the symmetry forbidden HOMO-to-LUMO transitions of ~2 eV and redox amphotericity. This was also supported by computed aromaticity indices (NICS, ACID, HOMA). Accordingly, substituents did not affect the fulfilment of the energetic criterion of SF, as the computed excited-state energy levels satisfied the required E(S1)/E(T1)>2 relationship. Further spectroscopic measurements revealed a concentration dependent quenching of the excited state and population of the S2 state on the nanosecond timescale, providing initial evidence for unusual photophysics and an alternative entry point for singlet fission with monobenzopentalenes.

Rhodanine-Based Chromophores: Fast Access to Capable Photoswitches and Application in Light-Induced Apoptosis.

Molecular photoswitches are highly desirable in all chemistry-related areas of research. They provide effective outside control over geometric and electronic changes at the nanoscale using an easy to apply, waste-free stimulus. However, simple and effective access to such molecular tools is typically not granted, and elaborate syntheses and substitution schemes are needed in order to obtain efficient photoswitching properties. Here we present a series of rhodanine-based photoswitches that can be prepared in one simple synthetic step without requiring elaborate purification. Photoswitching is induced by UV and visible light in both switching directions, and thermal stabilities of the metastable states as well as quantum yields are very high. An additional benefit is the hydrogen-bonding capacity of the rhodanine fragment, which enables applications in supramolecular or medicinal chemistry. We further show that the known rhodanine-based inhibitor SMI-16a is a photoswitchable apoptosis inducer. The biological activity of SMI-16a can effectively be switched ON or OFF by reversible photoisomerization between the inactive E and the active Z isomer. Rhodanine-based photoswitches therefore represent an easy to access and highly valuable molecular toolbox for implementing light responsiveness to the breadth of functional molecular systems.

Synthesis of Waixenicin A: Exploring Strategies for Nine-Membered Ring Formation.

We present a comprehensive account on our efforts behind the recently published synthesis of waixenicin A. Our approach for constructing the dihydropyran ring relied on an Achmatowicz rearrangement. For the assembly of the nine-membered ring, four distinct strategies were investigated. Our initial attempts using radical-based addition/fragmentation reactions targeting the C7-C11 bond proved unsuitable for accessing the 6/9-bicycle. By employing anionic fragmentation conditions at the furfuryl alcohol stage, we successfully reached a 5/9-bicycle. However, subsequent ring-expansion was unsuccessful. Alternative approaches, such as Nozaki-Hiyama-Kishi or Heck reactions to connect the C6-C7 bond, also encountered difficulties, with no nine-membered ring formation observed. Our first breakthrough came from our attempts to install the C5-C6 bond via an intramolecular alkylation. Surprisingly, subsequent functional group modifications proved unexpectedly challenging, necessitating a redesign of our synthetic route. Drawing from all our investigations, we concluded that construction of the C9-C10 bond would enable efficient nine-membered ring alkylation and would facilitate the installation of the desired substitution pattern along the southern periphery. Exploration of this strategy yielded further surprises but ultimately led to the successful synthesis of waixenicin A and 9-deacetoxy-14,15-deepoxyxeniculin. For the latter compound, a bioinspired one-step rearrangement to xeniafauranol A was achieved.

Azotriptycenes: Photoswitchable Molecular Brakes.

The control of molecular motions is a central topic of molecular machine research. Molecular brakes are fundamental building blocks towards such goal as they allow deliberately decelerating specific motions after an outside stimulus is applied. Here we present azotriptycenes as structural framework for light-controlled molecular brakes. The intrinsic kinetics and their changes upon azotriptycene isomerization are scrutinized comprehensively by a mixed theoretical and variable temperature NMR approach. With azotriptycenes C-N bond rotation rates can be decelerated or accelerated reversibly by up to five orders of magnitude. Rate change effects are highly localized and are strongest for the C-N bond connecting a triptycene rotor fragment to the central diazo group. The detailed mechanistic insights provide a solid basis for further conscious design and applications in the future.

Chiral Isochalcogenourea-Catalysed Enantioselective (4+2) Cycloadditions of Allenoates.

Allenoates are versatile building blocks which are primarily activated and controlled using chiral tert. phosphine and tert. amine Lewis bases. We herein report the first example of allenoate activation by using chiral isochalcogenoureas (IChU) for formal (4+2) cycloaddition reactions. Compared to established phosphine and amine catalysis, the use of these easily available Lewis bases enables new stereoselective reaction pathways proceeding with high enantioselectivities, diastereoselectivities, and in good yields. In addition, the factors governing enantioselectivity and the origin of the observed differences compared to other commonly used Lewis bases are explained.

Acupuncture reduces mechanical ventilation time in critically ill patients: A systematic review and meta-analysis of randomized control trials.

BACKGROUND: Mechanical Ventilation (MV) is an essential life support machine, frequently utilized in an Intensive Care Unit (ICU). Recently, a growing number of clinical trials have investigated the effect of acupuncture treatment on MV outcomes. OBJECTIVES: This study investigated the safety and efficacy of acupuncture treatment for critically ill patients under MV. METHODS: In this systematic review and meta-analysis of randomized controlled trials, the efficacy of acupuncture related interventions was compared to routine ICU treatments, and sham/control acupuncture as control interventions applied to ICU patients undergoing MV. The databases of PubMed, Cochrane Library, and Web of Science were extensively searched in the month of April 2022. The primary outcome measurements were defined as total MV time, ICU length of stay, and mortality. The Cochrane Collaboration risk of bias tool was employed to analyze the severity of bias. The meta-analysis was conducted using Review Manager 5.3 software. The quality of evidence was evaluated according to the GRADE approach. RESULTS: A total of 10 clinical trials were included in this investigation. When comparing the performance of acupuncture-related interventions to that of the reported control interventions, the results of the meta-analysis revealed a significant reduction in the total number of MV days as well as the duration of ICU length of stay following acupuncture treatment (MD -2.06 [-3.33, -0.79] P = 0.001, I2 = 55 %, MD-1.26 [-2.00, -0.53] P = 0.0008, I2 = 77 %, respectively). A reduction in the total mortality was similarly observed (RR = 0.67 [0.47, 0.94] P = 0.02, I2 = 0 %). CONCLUSION: This systematic review and meta-analysis identified a noteworthy reduction in the total MV days, time spent in the ICU, as well as the total mortality following acupuncture related interventions. However, the small sample size, risk of bias and existing heterogeneity should be taken into consideration. The results of this study are promising and further investigations in this field are warranted.

A photochemical method to evidence directional molecular motions.

Light driven synthetic molecular motors represent crucial building blocks for advanced molecular machines and their applications. A standing challenge is the development of very fast molecular motors able to perform rotations with kHz, MHz or even faster frequencies. Central to this challenge is the direct experimental evidence of directionality because analytical methods able to follow very fast motions rarely deliver precise geometrical insights. Here, a general photochemical method for elucidation of directional motions is presented. In a macrocyclization approach the molecular motor rotations are restricted and forced to proceed in two separate ~180° rotation-photoequilibria. Therefore, all four possible photoinduced rotation steps (clockwise and counterclockwise directions) can be quantified. Comparison of the corresponding quantum yields to the unrestricted motor delivers direct evidence for unidirectionality. This method can be used for any ultrafast molecular motor even in cases where no high energy intermediates are present during the rotation cycle.

Acupuncture effect on dumping syndrome in esophagus cancer patients with feeding jejunostomy: A study protocol for a single blind randomized control trial.

INTRODUCTION: Esophagus cancer patients are at risk for malnourishment. Feeding jejunostomy is used in advanced esophagus cancer patients in order to support and supplement the patients' nutrition needs. In dumping syndrome, the food is rapidly introduced into the intestine at a rate that is faster than normal, it is associated with both digestive system and vasoactive symptoms. Dumping syndrome has an association with both esophagus cancer patients and feeding jejunostomy. In the mid and long term, dumping syndrome is an important issue that contributes to the risk of malnourishment in advanced esophagus cancer patients. In recent studies, acupuncture was effective in regulating digestive symptoms. Acupuncture is considered to be a safe intervention, that was previously shown to be effective in treating digestive-related symptoms. METHODS: Sixty advanced esophageal cancer patients post-feeding jejunostomy will be divided into 2 equal groups, an intervention group (n = 30) and a control group (n = 30). Patients in the intervention group will receive acupuncture using the following acupoints: ST36 (Zusanli), ST37 (Shangjuxu), ST39 (Xiajuxu), PC6 (Neiguan), LI4 (Hegu), and Liv 3 (Taichung). Patients in the control group will receive shallow acupuncture on 12 non-acupoints (sham points), 1 cm from the above mention points. Patients and assessors will be blind to trial allocation. Both groups will receive acupuncture twice a week for 6 weeks. The main outcome measurements are: body weight, BMI, Sigstad's score, and the Arts' dumping questionnaire. DISCUSSION: There are no previous studies that have examined the use of acupuncture on patients with dumping syndrome. This single-blind randomized control trial will investigate the effect of acupuncture on dumping syndrome in advanced esophagus cancer patients with feeding jejunostomy. The results will determine if verum acupuncture can affect dumping syndrome and prevent weight loss.

Mechanistic Elucidation of the Hula-Twist Photoreaction in Hemithioindigo.

The Hula-Twist (HT) photoreaction represents a fundamental photochemical pathway for bond isomerizations and is defined by the coupled motion of a double bond and an adjacent single bond. This photoreaction has been suggested as the defining motion for a plethora of light-responsive chromophores such as retinal within opsins, coumaric acid within photoactive yellow protein, or vitamin D precursors, and stilbenes in solution. However, due to the fleeting character of HT photoproducts a direct experimental observation of this coupled molecular motion was severely hampered until recently. To solve this dilemma, the Dube group has designed a molecular framework able to deliver unambiguous experimental evidence of the HT photoreaction. Using sterically crowded atropisomeric hemithioindigo (HTI) the HT photoproducts are rendered thermally stable and can be observed directly after their formation. However, following the ultrafast excited state process of the HT photoreaction itself has not been achieved so far and thus crucial information for an elementary understanding is still missing. In this work, we present the first ultrafast spectroscopy study of the HT photoreaction in HTI and probe the competition between different excited state processes. Together with extensive excited state calculations a detailed mechanistic picture is developed explaining the significant solvent effects on the HT photoreaction and revealing the intricate interplay between productive isomerizations and unproductive twisted intramolecular charge transfer (TICT) processes. With this study essential insights are thus gained into the mechanism of complex multibond rotations in the excited state, which will be of primary importance for further developments in this field.

Concept and Pictogram-Based User-Interface Design of a Helper Tool for People with Aphasia.

BACKGROUND: Aphasia describes the lack of the already gained ability to use language in a common way. "Language" here covers all variations of forming or understanding messages. OBJECTIVES: The APH-Alarm project aims to develop a service concept that provides alternative communication options for people with Aphasia to trigger timely help when needed. It considers that a typical user may not be familiar with modern technologies and offers several simple and intuitive options. METHODS: The approach is based on event detection of gestures (during daytime or in bed), movement pattern recognition in bed, and an easy-to-use pictogram-based smartphone app. RESULTS: Agile evaluation of the smartphone app showed a promising outcome. CONCLUSION: The idea of a versatile and comprehensive solution for aphasic people to easily contact private or public helpers based on their actions or automatic detection is promising and will be further investigated in an upcoming field trial.

Light as a Possible Guidance in the Toilet Room from the View of Dementia Experts.

Digital assistants and guidance systems may support persons with dementia (PwD) during the independent use of the toilet room. The paper investigates the possible use of different light sources to provide visual stimuli for guidance. Demonstrators were presented to dementia experts to gather their views. While there is no evidence yet, it can be concluded that light stimuli in the toilet environment could be a (maybe only additional) option for guidance to be further investigated. The different methods must be always adapted to the local situation and the individual user characteristics.

Investigating the characteristics of residential end uses of water: A worldwide review.

A detailed characterization of residential water consumption is essential for ensuring urban water systems' capability to cope with changing water resources availability and water demands induced by growing population, urbanization, and climate change. Several studies have been conducted in the last decades to investigate the characteristics of residential water consumption with data at a sufficiently fine temporal resolution for grasping individual end uses of water. In this paper, we systematically review 114 studies to provide a comprehensive overview of the state-of-the-art research about water consumption at the end-use level. Specifically, we contribute with: (1) an in-depth discussion of the most relevant findings of each study, highlighting which water end-use characteristics were so far prioritized for investigation in different case studies and water demand modelling and management studies from around the world; and (2) a multi-level analysis to qualitatively and quantitatively compare the most common results available in the literature, i.e. daily per capita end-use water consumption, end-use parameter average values and statistical distributions, end-use daily profiles, end-use determinants, and considerations about efficiency and diffusion of water-saving end uses. Our findings can support water utilities, consumers, and researchers (1) in understanding which key aspects of water end uses were primarily investigated in the last decades; and (2) in exploring their main features considering different geographical, cultural, and socio-economic regions of the world.

Synthesis, Solid State Structure, and Cytotoxic Activity of a Complex Dimer of Yttrium with Anthranilic Acid against Cancer Cells.

This paper presents the synthesis and isolation of a new binuclear complex of yttrium with anthranilic acid (HA). The complex [Y2(HA)6(H2O)4] Cl6.2C2H5OH (C1) was obtained as single crystals that its X-ray analysis revealed its triclinic P-1 space group in addition to anti-prismatic geometry around each of the yttrium ions. In the complex, the anthranilic acid ligands are bidentate, zwitter ionic and neutral, and the yttrium ions' charge is only compensated by six chloride ions. The cytotoxicity of this complex against human breast cancer MDA-MB-231 cells, prostate cancer PC-3 cells, and bladder cancer T-24 cells was evaluated. This yttrium complex displayed more cytotoxic activity against the bladder cancer cells with an IC50 value of 307.7 µg/ml (223 µM). On the other hand, the activities of complex C1 against the MDA-MB-231 and PC-3 cells were less significant respectively with IC50 values of 1097 µg/ml (796 µM) and 921 µg/ml (669 µM).

Stable Monoareno-pentalenes with Two Olefinic Protons.

A novel class of stable monoareno-pentalenes is introduced that have an olefinic proton on each five-membered ring of the pentalene subunit. Their synthesis was accomplished via a regioselective carbopalladation cascade reaction between ortho-arylacetyleno gem-dibromoolefins and TIPS-acetylene. These molecules could be experimental probes of magnetic (anti)aromaticity effects.