Light Emitting Molecular Devices Based on Transition Metals

Multicomponent systems have been designed, which are able to perform defined functions related to light emission and quenching. The desired function can be switched ON/OFF by the operator through a chemical input, either a change of pH or a variation of the redox potential. Transition metals (e.g. Ni(II), Cu(II)) are key constituents within the considered systems, playing a distinctive architectural role and favouring electron transfer processes

Colorectal Cancer Stage at Diagnosis Before vs During the COVID-19 Pandemic in Italy

IMPORTANCE Delays in screening programs and the reluctance of patients to seek medical attention because of the outbreak of SARS-CoV-2 could be associated with the risk of more advanced colorectal cancers at diagnosis. OBJECTIVE To evaluate whether the SARS-CoV-2 pandemic was associated with more advanced oncologic stage and change in clinical presentation for patients with colorectal cancer. DESIGN, SETTING, AND PARTICIPANTS This retrospective, multicenter cohort study included all 17 938 adult patients who underwent surgery for colorectal cancer from March 1, 2020, to December 31, 2021 (pandemic period), and from January 1, 2018, to February 29, 2020 (prepandemic period), in 81 participating centers in Italy, including tertiary centers and community hospitals. Follow-up was 30 days from surgery. EXPOSURES Any type of surgical procedure for colorectal cancer, including explorative surgery, palliative procedures, and atypical or segmental resections. MAIN OUTCOMES AND MEASURES The primary outcome was advanced stage of colorectal cancer at diagnosis. Secondary outcomes were distant metastasis, T4 stage, aggressive biology (defined as cancer with at least 1 of the following characteristics: signet ring cells, mucinous tumor, budding, lymphovascular invasion, perineural invasion, and lymphangitis), stenotic lesion, emergency surgery, and palliative surgery. The independent association between the pandemic period and the outcomes was assessed using multivariate random-effects logistic regression, with hospital as the cluster variable. RESULTS A total of 17 938 patients (10 007 men [55.8%]; mean [SD] age, 70.6 [12.2] years) underwent surgery for colorectal cancer: 7796 (43.5%) during the pandemic period and 10 142 (56.5%) during the prepandemic period. Logistic regression indicated that the pandemic period was significantly associated with an increased rate of advanced-stage colorectal cancer (odds ratio [OR], 1.07; 95%CI, 1.01-1.13; P = .03), aggressive biology (OR, 1.32; 95%CI, 1.15-1.53; P < .001), and stenotic lesions (OR, 1.15; 95%CI, 1.01-1.31; P = .03). CONCLUSIONS AND RELEVANCE This cohort study suggests a significant association between the SARS-CoV-2 pandemic and the risk of a more advanced oncologic stage at diagnosis among patients undergoing surgery for colorectal cancer and might indicate a potential reduction of survival for these patients

Evolving trends in the management of acute appendicitis during COVID-19 waves. The ACIE appy II study

Background: In 2020, ACIE Appy study showed that COVID-19 pandemic heavily affected the management of patients with acute appendicitis (AA) worldwide, with an increased rate of non-operative management (NOM) strategies and a trend toward open surgery due to concern of virus transmission by laparoscopy and controversial recommendations on this issue. The aim of this study was to survey again the same group of surgeons to assess if any difference in management attitudes of AA had occurred in the later stages of the outbreak. Methods: From August 15 to September 30, 2021, an online questionnaire was sent to all 709 participants of the ACIE Appy study. The questionnaire included questions on personal protective equipment (PPE), local policies and screening for SARS-CoV-2 infection, NOM, surgical approach and disease presentations in 2021. The results were compared with the results from the previous study. Results: A total of 476 answers were collected (response rate 67.1%). Screening policies were significatively improved with most patients screened regardless of symptoms (89.5% vs. 37.4%) with PCR and antigenic test as the preferred test (74.1% vs. 26.3%). More patients tested positive before surgery and commercial systems were the preferred ones to filter smoke plumes during laparoscopy. Laparoscopic appendicectomy was the first option in the treatment of AA, with a declined use of NOM. Conclusion: Management of AA has improved in the last waves of pandemic. Increased evidence regarding SARS-COV-2 infection along with a timely healthcare systems response has been translated into tailored attitudes and a better care for patients with AA worldwide

Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

Transition metal based Chemosensing Ensembles: ATP sensing in physiological conditions.

Sensing of biologically relevant anionic substrates in physiological conditions, employing the strategy of the chemosensing ensembles, is reported. Coordination of a fluorescent indicator to a dicopper(II) polyazamacrocyclic receptor ([Cu-2(L)]) results in the collapse of its fluorescence emission. Competitive binding of substrates for the receptor releases the indicator in solution, with full emission recovery. The spectral changes obtained for some indicators and substrates were analysed to determine their respective association constants for the receptor. Discrimination of micromolar ATP quantities from other interferents (small inorganic anions and well-known neurotransmitters) is improved by a judicious choice of the indicator, the resulting ATP sensor promising interesting biological applications

The design of fluorescent sensors for anions: taking profit from the metal-ligand interaction and exploiting two distinct paradigms.

Fluorescent sensors are molecular systems consisting of a receptor moiety and of a fluorogenic fragment, which are capable of recognising a given analyte and signalling recognition through a variation of the emission intensity. The fluorogenic fragment responsible of the signal can be associated to the receptor either covalently or non-covalently, giving rise to two well distinct classes of fluorosensors and sensing paradigms. The design of fluorescent sensors is described, with a special attention to the sensing of anionic groups (including those of amino acids). In any case, it seems convenient that the receptor moiety contains one or more metal centres, which establish strong coordinative interactions with the envisaged anionic substrate. Selectivity is related to the energy of the metal-analyte interaction and can be achieved by taking profit of the concepts developed in more than one hundred years of coordination chemistry. As an example, recognition and sensing of the amino acid histidine is considered in detail, which is based on the attitude of the imidazole residue to deprotonate and bridge two MII ions prepositioned at the right distance, within a defined coordinative framework (M = Cu, Zn

(Benzylideneamino)thioureas – Chromogenic Interactions with Anions andN–H Deprotonation

A family of neutral N-(R1-substituted-benzylideneamino)-N- (R2-substituted-phenyl)thioureas (LH) were designed as anion receptors, and their interactions with anions in MeCN solution were investigated through spectrophotometric and 1H NMR titration experiments. While oxo anions (e.g., CH3COO–, H2PO4 –) form genuine H-bond complexes based on complementary N–H···O interactions with LH receptors, the fluoride ion undergoes a two-step interaction, involving (i) formation of the [LH···F]– complex, and (ii) release of an HF molecule to give [HF2]– and the deprotonated form of the receptor (L–). Deprotonation takes place at the N–H fragment closer to the R2-substituted phenyl ring, as indicated by 1H NMR spectroscopy. The logK values for the formation of the [LH···CH3COO]– H-bond complexes vary over the 3.1–3.8 range and are scarcely affected by the natures of the R1 and R2 substituents. The investigated systems may be of interest in the design of molecular devices in which the optical properties of different and distant substituents are modulated through the interaction of a chosen anion at the thiourea site

A yellow transient forms in the decomposition in acidic solution of the blue-violet nickel(II) complex of a trifurcated hexamine

In the decomposition in acidic solution of the octahedral high-spin nickel(II) complex with the hexamine sen, a thermodynamically unstable, kinetically controlled, square-planar low-spin species forms, with a lifetime of 5 s

Crystal and molecular structure and solution behaviour of low-spin (3-methyl-1,3,5,8,12-pentaazacyclotetradecane)κ4N1,N5,N8,N12)nickel(II) diperchlorate

Template reaction of 3,7-diazanonane-1,9-diamine, formaldehyde and methylamine, in the presence of Ni(ClO4)2, gives the pentaazamacrocyclic low-spin complex [Ni(azacyclam)][ClO4]2 (azacyclam = 3-methyl-1,3,5,8,12-pentaazacyclotetradecane), whose crystal and molecular structure was determined from single-crystal X-ray diffraction data collected with the use of Cu-K-alpha radiation: space group P2(1)2(1)2(1) with a = 15.967(3), b = 13.497(3), c = 8.737(2) angstrom, alpha = beta = gamma = 90-degrees, Z = 4 (R = 0.0705). Only the four secondary amine nitrogen atoms of azacyclam are bound to the metal, according to a regular square-planar stereochemistry, the lone pair of the tertiary nitrogen atom, N(1), being exposed. In particular, the N(1)C3 group is flattened, probably due to a long-range electrostatic interaction between N(1) and the metal. As a consequence, N(1) displays a very small affinity towards aqueous H+ (pK(a) < 2). The [Ni(azacyclam)]2+ complex in aqueous solution displays the high spin-low spin (blue-to-yellow) interconversion, typical of complexes of cyclam. However, in contrast, addition of HCl favours formation of the high-spin form. This unusual behaviour is ascribed to protonation of the N(1) atom, at acid concentrations of 0.5-1.0 mol dm-3, and to axial co-ordination of a hydrogen-bonded chloride ion. Addition of HClO4 first favours formation of the high-spin species, then that of the low-spin complex: in this case, the hydrogen-bond-facilitated axial co-ordination of a water molecule is hypothesized

A structurally characterized azide-bridged dinuclear nickel(II) cryptate

The macrobicyclic ligand L2 forms dimetallic Ni-II cryptate species in a delimited pH range, which are further able to include one N-3-anion. The molecular structure of the azide-bridged complex shows an almost linear (NiNNNNiII)-N-II arrangement and a different coordination at the two metal sites (one Ni-II being octahedral, the other trigonal bipyramidal)