Proof-of-Concept Quantum Simulator Based on Molecular Spin Qudits.

The use of d-level qudits instead of two-level qubits can largely increase the power of quantum logic for many applications, ranging from quantum simulations to quantum error correction. Magnetic molecules are ideal spin systems to realize these large-dimensional qudits. Indeed, their Hamiltonian can be engineered to an unparalleled extent and can yield a spectrum with many low-energy states. In particular, in the past decade, intense theoretical, experimental, and synthesis efforts have been devoted to develop quantum simulators based on molecular qubits and qudits. However, this remarkable potential is practically unexpressed, because no quantum simulation has ever been experimentally demonstrated with these systems. Here, we show the first prototype quantum simulator based on an ensemble of molecular qudits and a radiofrequency broadband spectrometer. To demonstrate the operativity of the device, we have simulated quantum tunneling of the magnetization and the transverse-field Ising model, representative of two different classes of problems. These results represent an important step toward the actual use of molecular spin qudits in quantum technologies.

Dalbavancin in catheter-related bloodstream infections: a pilot study.

Background: Catheter-related bloodstream infections (CRBSI) represent a frequent complication of vascular catheterization, with high morbidity, mortality, and associated costs. Most infections are caused by Gram-positive bacteria; thus dalbavancin, a new long-acting lipoglicopeptide, may have a role in early patient discharge strategies optimizing treatment and reducing overall costs. Methods: In this small pilot feasibility study, we assessed the efficacy and safety of a "single step" treatment strategy combining dalbavancin administration (1500 mg IV single dose), catheter removal, and early discharge in adult patients admitted to medical wards in a three-year period. Results: We enrolled sixteen patients with confirmed Gram-positive CRBSI, with a mean age of 68 years and relevant comorbidities (median Charlson Comorbidity index=7). The most frequent causative agents were staphylococci, with 25% of methicillin-resistant strains, and the majority of infected devices were short term central venous catheter (CVC) and peripherally inserted central catheter (PICC). Ten out of sixteen patients had been treated empirically before dalbavancin administration. The mean time from dalbavancin administration to discharge was 2 days; none of the patients had adverse drug-related reactions; at 30- and 90-day follow-up, no patients have been readmitted to the hospital due to bacteraemia recurrence. Conclusions: Our results indicate that single-dose dalbavancin is highly effective, well-tolerated, and cost-saving for Gram-positive CRBSI.

Liver injury in COVID-19 patients with non-alcoholic fatty liver disease: an update.

The coronavirus disease 2019 (COVID-19) pandemic has revolutionized the priorities of the medical society worldwide. Although most patients infected with SARS-CoV-2 exhibit respiratory symptoms, other organs may also be involved, including the liver, often resulting in liver injury. Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in the world, and its prevalence is expected to increase together with the epidemics of type 2 diabetes and obesity. Data about liver injury during COVID-19 are numerous, while overviews of this infection in patients with NAFLD, both in terms of respiratory and liver, are emerging. In this review, we summarise the current research focusing on COVID-19 in NAFLD patients and discuss the association between liver injury in COVID-19 subjects and non-alcoholic fatty liver disease.

Origin of the Unusual Ground-State Spin S = 9 in a Cr10 Single-Molecule Magnet.

The molecular wheel [Cr10(OMe)20(O2CCMe3)10], abbreviated {Cr10}, with an unusual intermediate total spin S = 9 and non-negligible cluster anisotropy, D/kB = -0.045(2) K, is a rare case among wheels based on an even number of 3d-metals, which usually present an antiferromagnetic (AF) ground state (S = 0). Herein, we unveil the origin of such a behavior. Angular magnetometry measurements performed on a single crystal confirmed the axial anisotropic behavior of {Cr10}. For powder samples, the temperature dependence of the susceptibility plotted as χT(T) showed an overall ferromagnetic (FM) behavior down to 1.8 K, whereas the magnetization curve M(H) did not saturate at the expected 30 µB/fu for 10 FM coupled 3/2 spin Cr3+ ions, but to a much lower value, corresponding to S = 9. In addition, the X-ray magnetic circular dichroism (XMCD) measured at high magnetic field (170 kOe) and 7.5 K showed the polarization of the cluster moment up to 23 µB/fu. The magnetic results can be rationalized within a model, including the cluster anisotropy, in which the {Cr10} wheel is formed by two semiwheels, each with four Cr3+ spins FM coupled (JFM/kB = 2.0 K), separated by two Cr3+ ions AF coupled asymmetrically (J23/kB = J78/kB = -2.0 K; J34/kB = J89/kB = -0.25 K). Inelastic neutron scattering and heat capacity allowed us to confirm this model leading to the S = 9 ground state and first excited S = 8. Single-molecule magnet behavior with an activation energy of U/kB = 4.0(5) K in the absence of applied field was observed through ac susceptibility measurements down to 0.1 K. The intriguing magnetic behavior of {Cr10} arises from the detailed asymmetry in the molecule interactions produced by small-angle distortions in the angles of the Cr-O-Cr alkoxy bridges coupling the Cr3+ ions, as demonstrated by ab initio and density functional theory calculations, while the cluster anisotropy can be correlated to the single-ion anisotropies calculated for each Cr3+ ion in the wheel.

Controlled coherent dynamics of [VO(TPP)], a prototype molecular nuclear qudit with an electronic ancilla.

We show that [VO(TPP)] (vanadyl tetraphenylporphyrinate) is a promising system to implement quantum computation algorithms based on encoding information in multi-level (qudit) units. Indeed, it embeds a nuclear spin 7/2 coupled to an electronic spin 1/2 by hyperfine interaction. This qubit-qudit unit can be exploited to implement quantum error correction and quantum simulation algorithms. Through a combined theoretical and broadband nuclear magnetic resonance study, we demonstrate that the elementary operations of such algorithms can be efficiently implemented on the nuclear spin qudit. Manipulation of the nuclear qudit can be achieved by resonant radio-frequency pulses, thanks to the remarkably long coherence times and the effective quadrupolar coupling induced by the strong hyperfine interaction. This approach may open new perspectives for developing new molecular qubit-qudit systems.

A Cost-Effective Semi-Ab Initio Approach to Model Relaxation in Rare-Earth Single-Molecule Magnets.

We discuss a cost-effective approach to understand magnetic relaxation in the new generation of rare-earth single-molecule magnets. It combines ab initio calculations of the crystal field parameters, of the magneto-elastic coupling with local modes, and of the phonon density of states with fitting of only three microscopic parameters. Although much less demanding than a fully ab initio approach, the method gives important physical insights into the origin of the observed relaxation. By applying it to high-anisotropy compounds with very different relaxation, we demonstrate the power of the approach and pinpoint ingredients for improving the performance of single-molecule magnets.

Radiofrequency to Microwave Coherent Manipulation of an Organometallic Electronic Spin Qubit Coupled to a Nuclear Qudit.

We report here a comprehensive characterization of a 3d organometallic complex, [V(Cp)2Cl2] (Cp = cyclopentadienyl), which can be considered as a prototypical multilevel nuclear qudit (nuclear spin I = 7/2) hyperfine coupled to an electronic qubit (electronic spin S = 1/2). By combining complementary magnetic resonant techniques, such as pulsed electron paramagnetic resonance (EPR) and broadband nuclear magnetic resonance (NMR), we extensively characterize its Spin Hamiltonian parameters and its electronic and nuclear spin dynamics. Moreover, we demonstrate the possibility to manipulate the qubit-qudit multilevel structure by resonant microwave and radiofrequency pulses, driving coherent Rabi oscillations between targeted electronuclear states. The obtained results demonstrate that this simple complex is a promising candidate for quantum computing applications.

Ceftobiprole and pneumonia in adults admitted to the emergency department is it time to assess a new therapeutic algorithm?

OBJECTIVE: Ceftobiprole is an advance generation cephalosporin which has broad-spectrum bacterial activity (both against Gram-positive and negative pathogens) and was approved for the treatment of community-acquired pneumonia (CAP) and non-ventilated hospital-acquired pneumonia (HAP) in most European countries. We aimed to evaluate the efficacy and safety of ceftobiprole in the treatment of pneumonia in a cohort of severely ill patients admitted to the emergency department (ED). METHODS: 1-year observational retrospective mono-centric study. Were defined two primary endpoints: first, to evaluate the clinical cure at the test-of-cure (TOC); the second, to evaluate the early improvement, defined as a reduction of symptoms and inflammatory parameters 72 hours after the start of treatment. The secondary endpoint is to evaluate the reduction of antibiotic "burden" using ceftobiprole despite standard of care in severe hospital-acquired pneumonia. RESULTS: During the study period, a total of 48 patients with severe pneumonia received ceftobiprole: twenty-two patients (45.8%) as empiric therapy, 9 (18.5%) as a de-escalation option from previous combination therapies, 13 patients (27.1%) as an escalation therapy from ceftriaxone or amoxicillin/clavulanate and four patients (8.3%) as a targeted therapy based on microbiological results. Ceftobiprole mean duration therapy was 10.2 days. Forty-six patients with severe pneumonia had an early clinical improvement 72 hours after the start of treatment (95.8%). In general, ceftobiprole was well tolerated; only one patient suspended the drug because of poor tolerability. The clinical cure at TOC was 85.4% and 30-days crude mortality was 10.4%. CONCLUSIONS: This study confirms that ceftobiprole is effective in severely ill patients with pneumonia at risk of poor outcomes.

An Unusual Case of Cholestatic Hepatitis due to Light-Chain Deposition Disease.

Light-chain deposition disease (LCDD) is a rare paraproteinaemia characterized by the deposition of monoclonal immunoglobulins with a non-fibrillar structure and hence Congo red negative deposits. Kidney disease is the more frequent manifestation, but other organs may also be involved. A 70-year-old man with hypertension and mild chronic renal failure showed a hepatomegaly without splenomegaly. His renal and liver test rapidly got worse. A serum electrophoresis and immunofixation isolated monoclonal kappa light-chain gammopathy, with serum free kappa light chain excess. The bone marrow biopsy showed the presence of interstitial infiltration of plasma cells like multiple myeloma type at initial phase. Periumbilical fat biopsy was negative. Echocardiography demonstrated an infiltrative cardiac disease. The biopsies of the duodenum small intestine mucosa showed flaps with eosinophil material (Masson's staining) with atrophic crypts and chronic inflammation at chorion level. Amyloid substance was negative. There was a strong positivity for light chains kappa compatible with LCDD. A liver biopsy confirmed this finding. Therapy with dexamethasone and bortezomib improved clinical state and hepatic and renal laboratory tests. Chemotherapy based on novel anti-myeloma agents should be rapidly considered in LCDD patients with severe organ involvement.

Slow Magnetic Relaxation of a 12-Metallacrown-4 Complex with a Manganese(III)-Copper(II) Heterometallic Ring Motif.

The heterobimetallic metallacrown (MC), (TMA)2{Mn(OAc)2[12-MCMn(III)Cu(II)N(shi)-4](CH3OH)}·2.90CH3OH, 1, where TMA+ is tetramethylammonium, -OAc is acetate, and shi3- is salicylhydroximate, consists of a MnII ion captured in the central cavity and alternating unambiguous and ordered manganese(III) and copper(II) sites about the MC ring, a first for the archetypal MC structure design. DC-magnetometry characterization and subsequent simulation with the Spin Hamiltonian H = -J1(s1 + s3)·s5 - J2(s2 + s4)·s5 - J3Σi=14si·si+1 + d(sz,12 + sz,32) + µBΣj=15gjsj·B indicates an S = 5/2 ground state and a sizable axial zero-field splitting on MnIII. AC-susceptibility measurements reveal that 1 displays slow magnetization relaxation akin to single-molecule magnet (SMM) behavior.

Correction: Anisotropy of CoII transferred to the Cr7Co polymetallic cluster via strong exchange interactions.

[This corrects the article DOI: 10.1039/C8SC00163D.].

Coherent Manipulation of a Molecular Ln-Based Nuclear Qudit Coupled to an Electron Qubit.

We demonstrate that the [Yb(trensal)] molecule is a prototypical coupled electronic qubit-nuclear qudit system. The combination of noise-resilient nuclear degrees of freedom and large reduction of nutation time induced by electron-nuclear mixing enables coherent manipulation of this qudit by radio frequency pulses. Moreover, the multilevel structure of the qudit is exploited to encode and operate a qubit with embedded basic quantum error correction.

Anisotropy of CoII transferred to the Cr7Co polymetallic cluster via strong exchange interactions.

The Cr7Co ring represents a model system to understand how the anisotropy of a CoII ion is transferred to the effective anisotropy of a polymetallic cluster by strong exchange interactions. Combining sizeable anisotropy with exchange interactions is an important point in the understanding and design of new anisotropic molecular nanomagnets addressing fundamental and applicative issues. By combining electron paramagnetic resonance and inelastic neutron scattering measurements with spin Hamiltonian and ab initio calculations, we have investigated in detail the anisotropy of the CoII ion embedded in the antiferromagnetic ring. Our results demonstrate a strong and anisotropic exchange interaction between the Co and the neighbouring Cr ions, which effectively transmits the anisotropy to the whole molecule.

Heterodimers of heterometallic rings.

Nine new complexes are reported involving linked heterometallic rings; one ring is designed as a ligand for the second, and the compounds produced can be regarded as molecular prototypes for implementing quantum gates featuring two subtly different qubits.

A detailed study of the magnetism of chiral {Cr7M} rings: an investigation into parametrization and transferability of parameters.

Compounds of general formula [Cr7MF3(Etglu)(O2C(t)Bu)15(Phpy)] [H5Etglu = N-ethyl-d-glucamine; Phpy = 4-phenylpyridine; M = Zn (1), Mn (2), Ni (3)] have been prepared. The structures contain an irregular octagon of metal sites formed around the penta-deprotonated Etglu(5-) ligand; the chirality of N-ethyl-d-glucamine is retained in the final product. The seven Cr(III) sites have a range of coordination environments, and the divalent metal site is crystallographically identified and has a Phpy ligand attached to it. By using complementary experimental techniques, including magnetization and specific heat measurements, inelastic neutron scattering, and electron paramagnetic resonance spectroscopy, we have investigated the magnetic features of this family of {Cr7M} rings. Microscopic parameters of the spin Hamiltonian have been determined as a result of best fits of the different experimental data, allowing a direct comparison with corresponding parameters found in the parent compounds. We examine whether these parameters can be transferred between compounds and compare them with those of an earlier family of heterometallic rings.

Linking [M(III)3] triangles with "double-headed" phenolic oximes.

Strapping two salicylaldoxime units together with aliphatic α,Ω-aminomethyl links in the 3-position gives ligands which allow the assembly of the polynuclear complexes [Fe(7)O(2)(OH)(6)(H(2)L1)(3)(py)(6)](BF(4))(5)·6H(2)O·14MeOH (1·6H(2)O·14MeOH), [Fe(6)O(OH)(7)(H(2)L2)(3)](BF(4))(3)·4H(2)O·9MeOH (2·4H(2)O·9MeOH) and [Mn(6)O(2)(OH)(2)(H(2)L1)(3)(py)(4)(MeCN)(2)](BF(4))(5)(NO(3))·3MeCN·H(2)O·5py (3·3MeCN·H(2)O·5py). In each case the metallic skeleton of the cluster is based on a trigonal prism in which two [M(III)(3)O] triangles are tethered together via three helically twisted double-headed oximes. The latter are present as H(2)L(2-) in which the oximic and phenolic O-atoms are deprotonated and the amino N-atoms protonated, with the oxime moieties bridging across the edges of the metal triangles. Both the identity of the metal ion and the length of the straps connecting the salicylaldoxime units have a major impact on the nuclearity and topology of the resultant cluster, with, perhaps counter-intuitively, the longer straps producing the "smallest" molecules.