Reversible Adsorption of Ammonia in the Crystalline Solid of a CO2H-Functionalized Cyclic Oligophenylene.

Ammonia (NH3) is a viable candidate for the storage and distribution of hydrogen (H2) due to its exceptional volumetric and gravimetric hydrogen energy density. Therefore, it is desirable to develop NH3 storage materials that exhibit robust stability across numerous adsorption-desorption cycles. While porous materials with polymeric frameworks are often used for NH3 capture, achieving reversible NH3 uptake remains a formidable challenge, primarily due to the high reactivity of NH3. Here, we advocate the use of CO2H-functionalized cyclic oligophenylene 1a with high chemical stability as a novel single-molecule-based adsorbent for NH3. Simple reprecipitation of 1a selectively yielded microporous crystalline solid 1a (N). Crystalline 1a (N) adsorbs up to 8.27 mmol/g of NH3 at 100 kPa and 293 K. Adsorbed NH3 in the pore of 1a (N) has a packing density of 0.533 g/cm3 at 293 K, which is close to the density of liquid NH3 (0.681 g/cm3 at 240 K). Crystalline 1a (N) also exhibits reversible NH3 adsorption over at least nine cycles, sustaining its storage capacity (1st cycle: 8.27 mmol/g; 9th cycle: 8.25 mmol/g at 100 kPa and 293 K) and crystallinity. During each desorption cycle, NH3 was removed from 1a (N) under reduced pressure (∼65 Pa), leaving <3% of the total uptake, and 1a (N) was fully purged under dynamic vacuum conditions (∼5 × 10-4 Pa at 293 K for 1 h) before the subsequent adsorption cycles. Thus, microporous crystalline 1a (N) can reliably adsorb and desorb NH3 repeatedly, which avoids the need for heat-based activation between cycles.

M/P Helicity Switching and Chiral Amplification in Double-Helical Monometallofoldamers.

Short-stranded double-helical monometallofoldamers capable of M/P-switching were constructed by the complexation of two strands, each with two L-shaped units linked by a 2,2'-bipyridine, with a Zn(II) cation. The helix terminals of the "double-helical form" folded by π-π interactions can unfold in solution to equilibrate with the "open forms" that are favored at higher temperatures. Interestingly, the helical chirality of the monometallofoldamers with chiral side chains induced a single-handed helix sense and controlled M/P-switching depending on achiral solvent stimuli. For instance, the (M)-helicity was favored in nonpolarized solvents (toluene, hexane, Et2O), whereas the (P)-helicity was favored in Lewis basic solvents (acetone, DMSO). Circular dichroism (CD) and rotating-frame overhauser enhancement spectroscopy (ROESY) measurements revealed that the conformational change of the chiral side chains due to interaction of Lewis basic solvents with the double helices induced helicity bias. These novel double-helical monometallofoldamers possessed a stable helical structure and exhibited switchable chiroptical properties (gabs ∼ 10-3-10-2). In addition, the chiral strand exhibited chiral transfer and amplification abilities through the formation of chiral heteroleptic double-helical monometallofoldamers when mixed with an achiral strand.

C-Reactive Protein/Albumin Ratio Is an Independent Risk Factor for Recurrence and Survival Following Curative Resection of Stage I-III Colorectal Cancer in Older Patients.

BACKGROUND: The number of older patients with cancer has increased, and colorectal cancer is expected to be affected by this trend. This study aimed to compare prognostic factors, including nutritional and inflammation-based indices, between patients aged ≥ 70 and < 70 years following curative resection of stage I-III colorectal cancer. PATIENTS AND METHODS: This study included 560 patients with stage I-III colorectal cancer who underwent curative resection between May 2010 and June 2018. A retrospective analysis was performed to identify prognosis-associated variables in patients aged ≥ 70 and < 70 years. RESULTS: Preoperative low body mass index, high C-reactive protein/albumin ratio, and comorbidities were mainly associated with poor prognosis in patients aged ≥ 70 years. Tumor factors were associated with a poor prognosis in patients aged < 70 years. The C-reactive protein/albumin ratio was independently associated with poor overall survival and recurrence-free survival in those aged ≥ 70 years. The time-dependent area under the curve for the C-reactive protein/albumin ratio was superior to those of other nutritional and inflammation-based indices in most postoperative observation periods in patients aged ≥ 70 years. CONCLUSIONS: Tumor factors were associated with a poor prognosis in patients aged < 70 years. In addition to lymph node metastasis, preoperative statuses were associated with poor prognosis in patients aged ≥ 70 years. Specifically, the preoperative C-reactive protein/albumin ratio was independently associated with long-term prognosis in patients aged ≥ 70 years with stage I-III colorectal cancer after curative resection.

Recognition of Amino Acid Salts by Temperature-Dependent Allosteric Binding with Stereodynamic Urea Receptors.

Positive homotropic artificial allosteric systems are important for the regulation of cooperativity, selectivity and nonlinear amplification. Stereodynamic homotropic allosteric receptors can transmit and amplify induced chirality by the first ligand binding to axial chirality between two chromophores. We herein report stereodynamic allosteric urea receptors consisting of a rotational shaft as the axial chirality unit, terphenyl units as structural transmission sites and four urea units as binding sites. NMR titration experiments revealed that the receptor can bind two carboxylate guests in a positive homotropic allosteric manner attributed to the inactivation by intramolecular hydrogen-bonding between urea units within the receptor. In addition, the VT-CD spectra observed upon binding of the urea receptor with l- or D-amino acid salts in MeCN showed interesting temperature-dependent Cotton effects, based on the differences of the receptor shaft unit and the guest structure. The successful discrimination of hydrocarbon-based side chains of amino acid salts indicated that the input of chiral and steric information for the guest was amplified as outputs of the Cotton effect and the temperature-dependence of VT-CD spectra through cooperativity of positive allosteric binding.

Structural Interconversion Based on Intramolecular Boroxine Formation.

A novel structural interconversion unit based on intramolecular boroxine formation has been developed. A macrocyclic triboronic acid consisting of three phenylboronic acid units linked by covalent linkers preferentially underwent intramolecular rather than intermolecular boroxine formation, resulting in a quantitative formation of tricyclic boroxine. This structural transformation was accompanied by changes in the polarity, flexibility, and size of the molecule. Dynamic interconversion between the macrocyclic triboronic acid and the tricyclic boroxine was achieved by simple heating/cooling, whereas no boroxine formation occurred upon heating when three boronic acid units were not connected by linkers. Thermodynamic analysis revealed that the entropic advantage of the intramolecular boroxine formation process resulted in these unique features. The entropically stabilized tricyclic boroxine also shows high stability with respect to hydrolysis.

Effect of abdominal aortic calcification on the prognosis and recurrence of colorectal cancer stages II-III: A retrospective cohort study.

PURPOSE: Abdominal aortic calcification (AAC) is a well-known risk marker for cardiovascular disease. However, its clinical effect on patients who underwent radical surgery for colorectal cancer (CRC) stages II-III is unclear. This study aimed to analyze the associations between AAC and prognosis of patients with stage II-III CRC. METHODS: To evaluate the effect of AAC on clinical outcomes, prognosis, and metastatic patterns of CRC, we analyzed 362 patients who underwent radical surgery for stage II-III CRC between 2010 and 2018. RESULTS: The high AAC group had significantly worse overall survival (OS), cancer-specific survival (CSS), and recurrence-free survival (RFS) after propensity score matching to adjust for differences in baseline characteristics of patients and tumors. In the multivariate Cox regression analyses, a high AAC was an independent risk factor for poor OS (hazard ratio [HR], 2.38; 95% confidence interval [CI], 1.23-4.59; p = 0.01), poor CSS (HR, 5.22; 95% CI, 1.74-15.6; p < 0.01), and poor RFS (HR, 1.83; 95% CI, 1.19-2.83; p < 0.01). A high AAC was not associated with a risk of lung metastasis or local or peritoneal recurrence, but a risk for liver metastasis of CRC. CONCLUSION: A high AAC showed a strong relationship with poor OS, CSS, and RFS after curative resection for stage II-III CRC. A high AAC was also associated with a risk for liver metastasis, which may worsen the prognosis in stage II-III CRC. AAC could be a new clinical tool for predicting the prognosis for patients in stage II-III CRC.

3D-Boronic Ester Architectures: Synthesis, Host-Guest Chemistry, Dynamic Behavior, and Supramolecular Catalysis.

Boronic esters are known to be formed simply by mixing boronic acids and alcohols under neutral conditions, and the equilibrium is in favor of the boronic esters when 1,2- or 1,3-diols are employed as alcohols. By utilizing the dynamic nature of the boronic ester formation, our group successfully constructed unique boron-containing 3D structures, such as ring-shaped macrocycles, cages, and tubes, based on the boronic ester formation of various aromatic di-, tri-, or hexaboronic acids with an originally designed tetrol 1 containing two sets of fixed 1,2-diol units oriented on the same face of an indacene framework. Various functions of the obtained boronates were further pursued to disclose the characteristic features of this system. This personal account describes our self-assembled boronate system using tetrol 1 including synthesis, host-guest chemistry, kinetic connection, characteristic dynamic behaviors, and supramolecular catalysis.

Determining a preventive strategy for ankle sprain injury through a questionnaire survey of coaches of junior high school basketball teams.

[Purpose] The purpose of this study was to determine a preventive strategy for ankle sprain injury through a questionnaire survey of coaches of junior high school basketball teams. [Participants and Methods] The questionnaire comprised questions concerning coaches' characteristics, prevention-related content, and collaboration with medical staff. We distributed the questionnaire to 108 coaches, of which 48 (41.7%) responded. [Results] The results revealed that none of the participant coaches had ever collaborated with medical staff. [Conclusion] Additional effort from medical staff is needed to hold seminars and contact coaches of junior high school teams in order to conduct an injury prevention program.

Molecular Mismatch Predicts T Cell-Mediated Rejection and De Novo Donor-Specific Antibody Formation After Living Donor Liver Transplantation.

Human leukocyte antigen (HLA) molecular mismatch (MM) analysis improves the prediction of clinical outcomes in kidney transplantation compared with prediction via traditional antigen MM. However, it remains unclear whether the level of MM can be used for risk stratification among liver transplantation (LT) recipients. A retrospective observational study of 45 living donor LTs was performed to evaluate eplet MM as a risk factor for both T cell-mediated rejection (TCMR) in the first month and de novo donor-specific antibody (dnDSA) formation. A total of 9 (20%) patients displayed TCMR. HLA-A, HLA-B, HLA-C, and HLA-DRB1 eplet MM numbers were not associated with TCMR. By contrast, HLA-DQB1 eplet MM (DQB1-EpMM) number was significantly high in patients with TCMR. The predicted indirectly recognizable HLA epitopes (PIRCHE-II) score for the HLA-DQB1 locus (DQB1-PIRCHE-II) was also significantly higher in the TCMR group than in the no-TCMR group. There was a high probability for TCMR to occur with either a DQB1-EpMM ≥7 or a DQB1-PIRCHE-II ≥13. Pretransplant mixed lymphocyte response analyses indicated that there were no significant differences between the antidonor T cell proliferation activities of patients with low-number (<7) and high-number (≥7) DQB1-EpMMs. However, the proportion of CD25 expression on proliferating antidonor CD8+ T cells, used as a cytotoxic activity marker, was high in DQB1-EpMMs ≥7. Moreover, both DQB1-EpMMs ≥9 and DQB1-PIRCHE-II ≥3 were predictors of dnDSA formation. Thus, MM analysis may be applied toward tailored immunosuppression based on individual risks.

Efficacy of upfront hepatectomy without neoadjuvant chemotherapy for resectable colorectal liver metastasis.

BACKGROUND: Hepatectomy for resectable colorectal liver metastasis (CRLM) is recommended. However, the efficacy of upfront hepatectomy without neoadjuvant chemotherapy (NAC) is unclear due to the uncertainty of perioperative systemic chemotherapy. Moreover, it is crucial to predict the prognosis when considering perioperative chemotherapy. This study evaluated the impact of neoadjuvant chemotherapy on the prognosis of patients with resectable CRLM and assessed the usefulness of Beppu's nomogram for predicting prognosis. METHODS: This retrospective study identified 88 consecutive inpatients who underwent primary hepatic resection for CRLM; 58 received neoadjuvant chemotherapy and 30 underwent upfront surgery. Factors associated with recurrence-free survival were identified via univariate and multivariate analysis. Furthermore, propensity score analysis using inverse probability of treatment weighting (IPTW) was performed. RESULTS: On univariate analysis, poor recurrence-free survival was associated with multiple tumors, advanced primary tumor stage, vascular invasion by the primary tumor, a Beppu's nomogram score ≥ 6, and neoadjuvant chemotherapy. On multivariate analysis, a Beppu's nomogram score ≥ 6 and neoadjuvant chemotherapy were independent risk factors for recurrence. Neoadjuvant chemotherapy recipients had a higher incidence of lymph node metastasis and vascular invasion than non-recipients. Propensity score analysis revealed no significant difference in the recurrence-free survival rate between these groups. CONCLUSIONS: Our results show that upfront hepatectomy without neoadjuvant chemotherapy can be considered for resectable CRLM treatment. Beppu's nomogram score can be a tool for predicting the prognosis of patients with CRLM.

[A Case of Rectal Neuroendocrine Carcinoma Treated with Multidisciplinary Therapy but with a Poor Prognosis].

A 70-year-old man presented to our hospital with weight loss. A colonoscopy revealed advanced cancer in the lower rectum. Computed tomography showed a tumor larger than 5 cm in the lower rectum with metastasis to the right lateral lymph node. The patient was diagnosed with advanced locally rectal cancer, and chemoradiotherapy(35 Gy plus S-1)was added after 6 courses of mFOLFOX6, and laparoscopic abdominal perineal resection and right lateral lymph nodes dissection were performed. Histopathological examination revealed endocrine cell carcinoma(pT3[A], pN0, M0, pStage Ⅱa). Four months after the operation, recurrence was found in the pelvis, lymph nodes, and lungs, and he died 9 months after the operation. Neuroendocrine carcinoma is relatively rare, so the further accumulation of cases and establishment of treatment methods are desired.

Fluorescent Short-Stranded Helical Foldamers Based on L-shaped Dibenzopyrrolo[1,2-a][1,8]naphthyridine.

Helical structures were constructed by using π-spacer-bridged dimers of dibenzopyrrolo[1,2-a][1,8]naphthyridine, which has a highly fluorescent L-shaped π-extended skeleton. Three dimers with biphenylene (dimer 1), phenanthrene (dimer 2), and m-phenylene (dimer 3) spacers, as well as a fixed-helical dimer 4 where two quinolone rings were covalently cross-linked, were designed and prepared. 1 H NMR and ROESY spectra revealed that dimers 1 and 2 adopted helical forms in solution, whereas dimer 3 did not. The helical conformation of 1 was strengthened by addition of either polar or nonpolar solvents to the chloroform solution, which suggested that π-π stacking was the main contributor to the stabilization of the helical structure. All of the dimers, including fixed-helical dimer 4, emitted fluorescence with high quantum yields (ϕ=0.79-0.86).

Dynamic Behavior of Covalent Organic Cages.

Discrete, large, covalent organic cages have recently been constructed by utilizing various types of dynamic covalent bond formation. The reversibility of bond formation can provide an opportunity to exhibit unique dynamic behavior; however, the transformation of such rigid cages to other structures remains challenging. To clarify the current status of this emerging research field, this Concept article gives an overview of recent progress of the dynamic behavior of covalent organic cages by classifying them into four types of transformation, namely, dimerization into the interlocked cages, transformation into different cage structures, exchange of components, and disassembly. The driving forces of such dynamic behavior and problems to be solved are also highlighted.

Dibenzopyrrolo[1,2-a][1,8]naphthyridines: Synthesis and Structural Modification of Fluorescent L-Shaped Heteroarenes.

The L-shaped, π-extended pentacycle dibenzopyrrolo[1,2-a][1,8]naphthyridine and its derivatives were synthesized using two methods: fully intramolecular [2 + 2 + 2] cycloaddition and oxidative aromatization using substituted carbodiimide and modification of an electron-rich indole ring of an L-shaped skeleton via electrophilic reaction and cross-coupling. These L-shaped compounds emitted fluorescence in high quantum yield. The position of substituents affected the fluorescence color through two different mechanisms, π-conjugation and skeletal distortion, which caused the substituted L-shaped compounds to emit fluorescence in a variety of colors and to exhibit solvato-fluorochromism.

Utilization of Donor-Acceptor Interactions for the Catalytic Acceleration of Nucleophilic Additions to Aromatic Carbonyl Compounds.

A conceptually new method for the catalytic electrophilic activation of aromatic carbonyl substrates, by utilizing donor-acceptor interactions between an electron-deficient macrocyclic boronic ester host ([2+2]BTH-F ) and an aromatic carbonyl guest substrate, was realized. In the presence of a catalytic amount of [2+2]BTH-F , dramatic acceleration of the nucleophilic addition of a ketene silyl acetal towards either electron-rich aromatic aldehydes or ketones was achieved. Several control experiments confirmed that inclusion of the aromatic substrates within [2+2]BTH-F , through efficient donor-acceptor interactions, is essential for the acceleration of the reaction.

Dynamic Interconversion between Boroxine Cages Based on Pyridine Ligation.

Dynamic interconversion between large covalent organic cages was achieved simply by heating or acid/base treatment. A mixture of the boroxine cages 12-mer and 15-mer was cleanly converted into a pyridine adduct of the 9-mer boroxine cage upon treatment with pyridine, and the geometry of N-coordinated boron atoms changed from trigonal to tetrahedral. The reverse reaction was achieved by heating or acid treatment. In this process, the larger boroxine cages 12-mer and 15-mer were found to be entropically favored owing to the release of free pyridine molecules from 9-mer⋅6 Py.

Self-Assembly of Nanometer-Sized Boroxine Cages from Diboronic Acids.

By use of the reversible trimerization of boronic acids, the series of boroxine cages 3-mer, 6-mer, and 12-mer were constructed from rationally designed diboronic acids whose bond angles between two C-B bonds are 60°, 84°, and 117°, respectively. Boroxine cages 6-mer and 12-mer have 1.5 and 2.5 nm sized cavities, respectively.

Inclusion of two different guest molecules within a rationally designed macrocyclic boronic ester in organic solvent.

The inclusion of two different guest molecules in a macrocyclic boronic ester in organic solvent utilizing only π-stacking interactions has been successfully realized. For this purpose, a new tetrol which has an appropriate distance between two 1,2-diol units for the inclusion of two aromatic molecules is designed and synthesized. Simple mixing of the new tetrol with 2,7-pyrenediboronic acid in the presence of pyrene-4,5-quinone efficiently affords the desired macrocyclic boronic ester, which is found by (1)H NMR spectroscopy, ESI-MS, and isothermal titration calorimetry studies to include one molecule each of a dinitronaphthalimide derivative and pyrene. Furthermore, inclusion of two planar molecules within the macrocyclic boronic ester is revealed by X-ray analysis.

Anti-Donor T-Cell Responses Are Not Necessarily Attenuated During Cytomegalovirus Infection in Kidney Transplant Recipients.

BACKGROUND: Cytomegalovirus (CMV), the most common opportunistic infection of kidney transplantation (KT), is preventable by prophylactic and preemptive antiviral drugs in CMV-immunoglobulin (Ig)G-positive donors. Our preemptive therapy optimized immunosuppressive doses based on mixed lymphocyte response (MLR) results, regardless of preoperative CMV-IgG serostatus pairing. This study used the MLR to compare the anti-donor T-cell responses between CMV antigenemia-positive and -negative cases. METHODS: One hundred patients underwent KT using a cyclosporine (CsA)-based immunosuppressive regimen at Hiroshima University Hospital. CMV antigenemia-positive cells were defined as 4/50,000 CMVpp65-positive cells. T-cell responses to allo-antigens were measured using MLR assays to evaluate patients' anti-donor immune reactivity. After analyzing the proliferation of CD4+ and CD8+ T-cell subsets, the stimulation indices of CD4+ or CD8+ T cells were quantified. The study used no prisoners, and the participants were neither coerced nor paid. The manuscript was created in compliance with the Helsinki Congress and the Declaration of Istanbul. RESULTS: Forty-three patients tested positive for CMV antigenemia within 3 months after KT. No significant differences were found between the CMV antigenemia-positive and -negative groups in the stimulation indices for CD4+ and CD8+ T-cell responses to anti-donor stimulation. However, T-cell responses to third-party stimuli during the postoperative month 1 were significantly less in the CMV antigenemia-positive than -negative group. CONCLUSION: Anti-donor T-cell responses are not necessarily attenuated during CMV infection in KT recipients. In CMV-infected KT recipients, caution should be exercised against inadvertent dose reduction of immunosuppressants.