PVDF-HFP Based, Quasi-Solid Nanocomposite Electrolytes for Lithium Metal Batteries.

Composite polymer electrolytes are systems of choice for future solid-state lithium metal batteries (LMBs). Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) is among the most interesting matrices to develop new generation quasi-solid electrolytes (QSEs). Here it is reported on nanocomposites made of PVDF-HFP and pegylated SiO2 nanoparticles. Silica-based hybrid nanofillers are obtained by grafting chains of poly(ethylene glycol) methyl ether (PEG) with different molecular weight on the surface of silica nanoparticles. The functionalized nanofiller improves the mechanical, transport and electrochemical properties of the QSEs, which show good ionic conductivity values and high resistance against dendrite penetration, ensuring boosted long and safe device operation. The most promising result is obtained by dispersing 5 wt% of SiO2 functionalized with short PEG chains (PEG750 , Mw = 750 g mol-1 ) in the PVDF-HFP matrix with an ease solvent-casting procedure. It shows ionic conductivity of 0.1 mS cm-1 at 25 °C, more than 250 h resistance to stripping/plating, and impressive results during cycling tests in LMB with LiFePO4 cathode.

A Decade of Nipple-Sparing Mastectomy: Lessons Learned in 3035 Immediate Implant-Based Breast Reconstructions.

BACKGROUND: Nipple-sparing mastectomy is commonly performed for breast cancer treatment or prevention. The authors present one of the largest breast reconstruction series in the literature. METHODS: A single-institution retrospective review was conducted from 2007 to 2019. RESULTS: The authors' query identified 3035 implant-based breast reconstructions after nipple-sparing mastectomy, including 2043 direct-to-implant and 992 tissue expander-to-implant reconstructions. The overall major complication rate was 9.15%, and the nipple necrosis rate was 1.20%. Therapeutic mastectomy was associated with higher overall complications and explantations compared with prophylactic mastectomy ( P < 0.01). In comparisons of unilateral and bilateral procedures, bilateral mastectomy had an increased risk for complications (OR, 1.46; 95% CI, 0.997 to 2.145; P = 0.05). Tissue-expander reconstructions had higher rates of nipple necrosis (1.9% versus 0.88%; P = 0.015), infection (4.2% versus 2.8%; P = 0.04), and explantation (5.1% versus 3.5%; P = 0.04) compared with direct-to-implant reconstruction. When assessing plane of reconstruction, the authors found similar rates of complications between subpectoral dual-plane and prepectoral reconstruction. There was no difference in complications between reconstruction with acellular dermal matrix or mesh compared with total or partial muscle coverage without acellular dermal matrix/mesh (OR, 0.749; 95% CI, 0.404 to 1.391; P = 0.361). Multivariable regression analysis revealed preoperative radiotherapy (OR, 2.465; 95% CI, 1.579 to 3.848; P < 0.001), smoking (OR, 2.53; 95% CI, 1.581 to 4.054; P < 0.001), and a periareolar incision (OR, 3.657; 95% CI, 2.276 to 5.875; P < 0.001) to be the strongest predictors of complications and nipple necrosis ( P < 0.05). CONCLUSIONS: Nipple-sparing mastectomy and immediate breast reconstruction has a low rate of complications. In this series, radiation therapy, smoking, and incision choice predicted overall complications and nipple necrosis, whereas direct-to-implant reconstruction and acellular dermal matrix or mesh did not increase risk. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Highly Reversible Ti/Sn Oxide Nanocomposite Electrodes for Lithium Ion Batteries Obtained by Oxidation of Ti3 Al(1-x) Snx C2 Phases.

Among the materials for the negative electrodes in Li-ion batteries, oxides capable of reacting with Li+ via intercalation/conversion/alloying are extremely interesting due to their high specific capacities but suffer from poor mechanical stability. A new way to design nanocomposites based on the (Ti/Sn)O2 system is the partial oxidation of the tin-containing MAX phase of Ti3 Al(1-x) Snx O2 composition. Exploiting this strategy, this work develops composite electrodes of (Ti/Sn)O2 and MAX phase capable of withstanding over 600 cycles in half cells with charge efficiencies higher than 99.5% and specific capacities comparable to those of graphite and higher than lithium titanate (Li4 Ti5 O12 ) or MXenes electrodes. These unprecedented electrochemical performances are also demonstrated at full cell level in the presence of a low cobalt content layered oxide and explained through an accurate chemical, morphological, and structural investigation which reveals the intimate contact between the MAX phase and the oxide particles. During the oxidation process, electroactive nanoparticles of TiO2 and Ti(1-y) Sny O2 nucleate on the surface of the unreacted MAX phase which therefore acts both as a conductive agent and as a buffer to preserve the mechanical integrity of the oxide during the lithiation and delithiation cycles.

Structure-Property Correlations in Aqueous Binary Na+/K+-CH3COO- Highly Concentrated Electrolytes.

Highly concentrated aqueous binary solutions of acetate salts are promising systems for different electrochemical applications, for example, energy storage devices. The very high solubility of CH3COOK allows us to obtain water-in-salt electrolyte concentrations, thus reducing ion activity and extending the cathodic stability of an aqueous electrolyte. At the same time, the presence of Li+ or Na+ makes these solutions compatible with intercalation materials for the development of rechargeable alkaline-ion batteries. Although there is a growing interest in these systems, a fundamental understanding of their physicochemical properties is still lacking. Here, we report and discuss the physicochemical and electrochemical properties of a series of solutions based on 20 mol kg-1 CH3COOK with different concentrations of CH3COONa. The most concentrated solution, 20 mol kg-1 CH3COOK + 7 mol kg-1 CH3COONa, gives the best compromise between transport properties and electrochemical stability, displaying a conductivity of 21.2 mS cm-1 at 25 °C and a stability window of up to 3 V in "ideal" conditions, i.e., using a small surface area and highly electrocatalytic electrode in a flooded cell. Careful Raman spectroscopy analyses help to address the interaction network, the phase evolution with temperature, and the crystallization kinetics.

Asociación entre diabetes y depresión en una población hospitalaria con diabetes mellitus

Introducción: Los pacientes diabéticos asocian depresión con una frecuencia mayor que la población general. Actualmente se considera que existe una relación bidireccional entre diabetes y depresión. Objetivo: El objetivo del estudio fue conocer la frecuencia de síntomas depresivos y su vínculo con factores sociodemográficos, control metabólico, tratamiento y complicaciones crónicas en una unidad de diabetes. Resultados: Se incluyeron 142 pacientes, la frecuencia de síntomas de depresión fue de 36.7%. Se encontró asociación con complicaciones crónicas y menor adherencia al tratamiento. Conclusiones: Es necesario utilizar métodos de screening para evaluar depresión en población de pacientes con diabetes.

Introduction: Diabetic patients associate depression with a higher frequency than the general population. It is currently considered that there is a bidirectional relationship between diabetes and depression. Objetive: The objective of the study was to determine the frequency of depressive symptoms and their relationship with sociodemographic factors, metabolic control, treatment, and chronic complications in a diabetes unit. Results: 142 patients were included, the frequency of depression symptoms was 36.7%. An association with chronic complications and lower adherence to treatment was found. Conclusions: It is necessary to use screening methods to assess depression in the population of patients with diabetes.

Introdução: Pacientes diabéticos associam a depressão com maior frequência do que a população em geral. Atualmente considera-se que existe uma relação bidirecional entre diabetes e depressão. Objetivo: O objetivo do estudo foi determinar a frequência de sintomas depressivos e sua relação com fatores sociodemográficos, controle metabólico, tratamento e complicações crônicas em uma unidade de diabetes. Resultados: 142 pacientes foram incluídos, a frequência de sintomas de depressão foi de 36,7%. Encontrou-se associação com complicações crônicas e menor adesão ao tratamento. Conclusões: É necessário usar métodos de triagem para avaliar a depressão na população de pacientes com diabetes.

Unveiling the Role of PEO-Capped TiO2 Nanofiller in Stabilizing the Anode Interface in Lithium Metal Batteries.

Lithium metal batteries (LMBs) will be a breakthrough in automotive applications, but they require the development of next-generation solid-state electrolytes (SSEs) to stabilize the anode interface. Polymer-in-ceramic PEO/TiO2 nanocomposite SSEs show outstanding properties, allowing unprecedented LMBs durability and self-healing capabilities. However, the mechanism underlying the inhibition/delay of dendrite growth is not well understood. In fact, the inorganic phase could act as both a chemical and a mechanical barrier to dendrite propagation. Combining advanced in situ and ex situ experimental techniques, we demonstrate that oligo(ethylene oxide)-capped TiO2, although chemically inert toward lithium metal, imparts SSE with mechanical and dynamical properties particularly favorable for application. The self-healing characteristics are due to the interplay between mechanical robustness and high local polymer mobility which promotes the disruption of the electric continuity of the lithium dendrites (razor effect).

Photo- and radio-luminescence of porphyrin functionalized ZnO/SiO2 nanoparticles.

The development of hybrid nanoscintillators is hunted for the implementation of modern detection technologies, like in high energy physics, homeland security, radioactive gas sensing, and medical imaging, as well as of the established therapies in radiation oncology, such as in X-ray activated photodynamic therapy. Engineering of the physico-chemical properties of nanoparticles (NPs) enables the manufacture of hybrids in which the conjugation of inorganic/organic components leads to increased multifunctionality and performance. However, the optimization of the properties of nanoparticles in combination with the use of ionizing radiation is not trivial: a complete knowledge on the structure, composition, physico-chemical features, and scintillation property relationships in hybrid nanomaterials is pivotal for any applications exploiting X-rays. In this paper, the design of hybrid nanoscintillators based on ZnO grown onto porous SiO2 substrates (ZnO/SiO2) has been performed in the view to create nanosystems potentially suitable in X-ray activated photodynamic therapy. Indeed, cytotoxic porphyrin dyes with increasing concentrations have been anchored on ZnO/SiO2 nanoparticles through amino-silane moieties. Chemical and structural analyses correlated with photoluminescence reveal that radiative energy transfer between ZnO and porphyrins is the principal mechanism prompting the excitation of photosensitizers. The use of soft X-ray excitation results in a further sensitization of the porphyrin emission, due to augmented energy deposition promoted by ZnO in the surroundings of the chemically bound porphyrin. This finding unveils the cruciality of the design of hybrid nanoparticles in ruling the efficacy of the interaction between ionizing radiation and inorganic/organic moieties, and thus of the final nanomaterial performances towards the foreseen application.

Promising Electrocatalytic Water and Methanol Oxidation Reaction Activity by Nickel Doped Hematite/Surface Oxidized Carbon Nanotubes Composite Structures.

Tailoring the precise construction of non-precious metals and carbon-based heterogeneous catalysts for electrochemical oxygen evolution reaction (OER) and methanol oxidation reaction (MOR) is crucial for energy conversion applications. Herein, this work reports the composite of Ni doped Fe2 O3 (Ni-Fe2 O3 ) with mildly oxidized multi-walled CNT (O-CNT) as an outstanding Mott-Schottky catalyst for OER and MOR. O-CNT acts as a co-catalyst which effectively regulates the charge transfer in Ni-Fe2 O3 and thus enhances the electrocatalytic performance. Ni-Fe2 O3 /O-CNT exhibits a low onset potential of 260 mV and overpotential 310 mV @ 10 mA cm-2 for oxygen evolution. Being a Mott-Schottky catalyst, it achieves the higher flat band potential of -1.15 V with the carrier density of 0.173×1024  cm-3 . Further, in presence of 1 M CH3 OH, it delivers the MOR current density of 10 mA cm-2 at 1.46 V vs. RHE. The excellent electrocatalytic OER and MOR activity of Ni-Fe2 O3 /O-CNT could be attributed to the synergistic interaction between Ni-doped Fe2 O3 and O-CNT.

Waste Face Surgical Mask Transformation into Crude Oil and Nanostructured Electrocatalysts for Fuel Cells and Electrolyzers.

A novel route for the valorization of waste into valuable products was developed. Surgical masks commonly used for COVID 19 protection by stopping aerosol and droplets have been widely used, and their disposal is critical and often not properly pursued. This work intended to transform surgical masks into platinum group metal-free electrocatalysts for oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) as well as into crude oil. Surgical masks were subjected to controlled-temperature and -atmosphere pyrolysis, and the produced char was then converted into electrocatalysts by functionalizing it with metal phthalocyanine of interest. The electrocatalytic performance characterization towards ORR and HER was carried out highlighting promising activity. At different temperatures, condensable oil fractions were acquired and thoroughly analyzed. Transformation of waste surgical masks into electrocatalysts and crude oil can open new routes for the conversion of waste into valuable products within the core of the circular economy.

Defect-assisted photocatalytic activity of glass-embedded gallium oxide nanocrystals.

The use of glassceramics in photocatalysis is an attractive option for the realization of smart optical fibers and self-cleaning windows. Here we present the photocatalytic activity of germanosilicate glasses embedding Ga2O3 nanocrystals prepared by batch melting and glass heat treatment. The powdered material is used for UV-assisted degradation of rhodamine in water. The kinetics show changes after repeated experiments. In the first cycle, the apparent rate is governed by a second-order reaction with a Gaussian-like shape, whereas the second cycle follows a first-order reaction. The modification appears to be correlated with perturbations in the defect population. Photoluminescence has been used to monitor the evolution of such defects. Kinetic data on photoreactions and defect formation have been modelled in a combined frame in which the defect concentration determines the photocatalytic activity. The results prove the photocatalytic ability of the studied glassceramics. Moreover, the general validity of the kinetic model can be of interest for other systems in which the photocatalytic response depends on photoreactive species concentration.

A physico-chemical investigation of highly concentrated potassium acetate solutions towards applications in electrochemistry.

Water-in-salt solutions, i.e. solutions in which the amount of salt by volume or weight is larger than that of the solvent, are attracting increasing attention in electrochemistry due to their distinct features that often include decomposition potentials much higher than those of lower concentration solutions. Despite the high solubility of potassium acetate (KAC) in water at room temperature (up to 25 moles of salt per kg of solvent), the low cost, and the large availability, the use of highly concentrated KAC solutions is still limited to a few examples in energy storage applications and a systematic study of their physical-chemical properties is lacking. To fill this gap, we have investigated the thermal, rheological, electrical, electrochemical, and spectroscopic features of KAC/water solutions in the compositional range between 1 and 25 mol kg-1. We show the presence of a transition between the "salt-in-solvent" and "solvent-in-salt" regimes in the range of 10-15 mol kg-1. Among the explored compositions, the highest concentrations (20 and 25 mol kg-1) exhibit good room temperature conductivity values (55.6 and 31 mS cm-1, respectively) and a large electrochemical potential window (above 2.5 V).

Prevalencia de Neuropatía Periférica en una Unidad de Diabetes / Prevalence of Peripheral Neuropathy in a Diabetes Unit / Prevalência de neuropatia periférica em uma unidade de diabetes

Resumen: La principal complicación crónica de la diabetes mellitus es la neuropatía, en particular la polineuropatía diabética. El objetivo de este estudio fue evaluar la prevalencia de polineuropatía y su asociación a factores de riesgo y complicaciones crónicas en una unidad de diabetes. En una población de 81 pacientes diabéticos, se encontró una prevalencia de polineuropatía de 34.6%. Es más frecuente y severa en la población de DM2, y se asoció con mayor tiempo de evolución de la enfermedad y complicaciones microangiopáticas. La polineuropatía sintomática predominó en el sexo femenino. Se concluye que la población diabética debe ser sometida a screening oportuno de polineuropatía.

Abstract: The main chronic complication of diabetes mellitus is neuropathy, in particular diabetic polyneuropathy. The objective of this study was to evaluate the prevalence of polyneuropathy and its association with risk factors and chronic complications in a diabetes unit. In a population of 81 diabetic patients, a polyneuropathy prevalence of 34.6% was found. It is more frequent and severe in the T2DM population, and was associated with longer disease progression and microangiopathic complications. Symptomatic polyneuropathy predominated in the female sex. It is concluded that the diabetic population should undergo timely screening for polyneuropathy.

Resumo: A principal complicação crônica do diabetes mellitus é a neuropatia, em particular a polineuropatia diabética. O objetivo deste estudo foi avaliar a prevalência de polineuropatia e sua associação com fatores de risco e complicações crônicas em uma unidade de diabetes. Em uma população de 81 pacientes diabéticos, foi encontrada uma prevalência de polineuropatia de 34,6%. É mais frequente e grave na população com DM2 e esteve associada a maior progressão da doença e complicações microangiopáticas. A polineuropatia sintomática predominou no sexo feminino. Conclui-se que a população diabética deve ser submetida a uma triagem oportuna da polineuropatia.

Control glicémico del paciente quirúrgico / Glycemic control of the surgical patient / Controle glicêmico do paciente cirúrgico

Resumen: Introducción: La diabetes mellitus es una patología de alta prevalencia, con mayor morbimortalidad en el paciente quirúrgico, tanto por la hipo como la hiperglicemia. Objetivos. Determinar si el control metabólico glicémico cumple las recomendaciones internacionales. Metodología: Se realizó un estudio descriptivo de todos los pacientes internados en áreas quirúrgicas. Se analizaron todas las glicemias capilares registradas en la historia clínica. Resultados : Se captaron 34 pacientes (predomina sexo masculino y con diabetes mellitus tipo 2), 21 fueron sometidos a una intervención quirúrgica, la mortalidad fue del 6%. La glicemia promedio fue superior a la recomendada internacionalmente, constituye episodios de hiperglicemia. Asimismo, se detectó la presencia de hipoglicemia. Conclusiones: Es deseable establecer estrategias para optimizar el control metabólico en la población con diabetes mellitus internada en áreas quirúrgicas.

Abstract: Introduction: Diabetes mellitus is a highly prevalent pathology, with higher morbidity and mortality in the surgical patient, both due to hypo and hyperglycemia. Goals. Determine if glycemic metabolic control meets international recommendations. Methodology: A descriptive study of all patients admitted to surgical areas was carried out. All capillary blood glucose levels recorded in the clinical history were analyzed. Results: 34 patients were captured (predominantly male and with type 2 diabetes mellitus), 21 underwent surgical intervention, mortality was 6%. The average glycemia was higher than the internationally recommended, it constitutes episodes of hyperglycemia. Likewise, the presence of hypoglycemia was detected. Conclusions: It is desirable to establish strategies to optimize metabolic control in the population with diabetes mellitus admitted to surgical areas.

Resumo: Introdução: O diabetes mellitus é uma patologia de alta prevalência, com maior morbimortalidade no paciente cirúrgico, tanto por hipo quanto por hiperglicemia. Metas. Determine se o controle metabólico glicêmico atende às recomendações internacionais. Metodologia: Foi realizado um estudo descritivo de todos os pacientes admitidos em áreas cirúrgicas. Todos os níveis de glicose no sangue capilar registrados na história clínica foram analisados. Resultados: 34 pacientes foram capturados (predominantemente do sexo masculino e com diabetes mellitus tipo 2), 21 foram submetidos a intervenção cirúrgica, a mortalidade foi de 6%. A média da glicemia foi superior ao recomendado internacionalmente, constituindo episódios de hiperglicemia. Da mesma forma, foi detectada a presença de hipoglicemia. Conclusões: É desejável estabelecer estratégias para otimizar o controle metabólico na população com diabetes mellitus admitida em áreas cirúrgicas.

Hydrocarbonoclastic Ascomycetes to enhance co-composting of total petroleum hydrocarbon (TPH) contaminated dredged sediments and lignocellulosic matrices.

Four new Ascomycete fungi capable of degrading diesel oil were isolated from sediments of a river estuary mainly contaminated by shipyard fuels or diesel oil. The isolates were identified as species of Lambertella, Penicillium, Clonostachys, and Mucor. The fungal candidates degraded and adsorbed the diesel oil in suspension cultures. The Lambertella sp. isolate displayed the highest percentages of oxidation of diesel oil and was characterised by the capacity to utilise the latter as a sole carbon source. This isolate showed extracellular laccase and Mn-peroxidase activities in the presence of diesel oil. It was tested for capacity to accelerate the process of decontamination of total petroleum hydrocarbon contaminated sediments, co-composted with lignocellulosic residues and was able to promote the degradation of 47.6% of the TPH contamination (54,074 ± 321 mg TPH/Kg of sediment) after two months of incubation. The response of the bacterial community during the degradation process was analysed by 16S rRNA gene meta-barcoding.

Surface Characterization of TiO2 Polymorphic Nanocrystals through 1H-TD-NMR.

Nanocrystals (NCs) surface characterization is a fundamental step for understanding the physical and chemical phenomena involved at the nanoscale. Surface energy and chemistry depend on particle size and composition, and, in turn, determine the interaction of NCs with the surrounding environment, their properties and stability, and the feasibility of nanocomposites. This work aims at extracting more information on the surface of different titanium dioxide polymorphs using 1H-TD-NMR of water. Taking advantage of the interaction between water molecules and titanium dioxide NCs, it is possible to correlate the proton transverse relaxation times ( T2) as the function of the concentration and the specific surface area (δp· Cm) and use it as an indicator of the crystal phase. Examples of three different crystals phase, rutile, anatase, and brookite, have been finely characterized and their behavior in water solution have been studied with TD-NMR. The results show a linear correlation between relaxivity ( R2) and their concentration Cm. The resulting slopes, after normalization for the specific surface, represent the surface/water interaction and range from 1.28 g m-2 s-1 of 50 nm rutile nanocrystals to 0.52 for similar sized brookite. Even higher slopes (1.85) characterize smaller rutile NCs, in qualitative accordance with the trends of surface energy. Thanks to proton relaxation phenomena that occur at the NCs surface, it is possible to differentiate the crystal phase and the specific surface area of titanium dioxide polymorphs in water solution.

Augmented excitation cross section of gadolinium ions in nanostructured glasses.

In this Letter, we present detailed absorption and emission data on nanostructured germanosilicate glasses and glass ceramics containing Ga2O3 nanophases and doped with Gd ions. The results show that these systems are suitable hosts for the enhancement of the excitation cross section of rare earth ions via energy transfer from the gallium oxide nanophase with a related quantum yield of 21%. The role of matrix composition and nanostructure morphology on the Gd emission is discussed.

PCB in the environment: bio-based processes for soil decontamination and management of waste from the industrial production of Pleurotus ostreatus.

Polychlorinated biphenyls (PCBs) are hazardous soil contaminants for which a bio-based technology for their recovery is essential. The objective of this study was to validate the exploitation of spent mushroom substrate (SMS), a low or null cost organic waste derived from the industrial production of P. ostreatus, as bulking agent in a dynamic biopile pilot plant. The SMS shows potential oxidative capacity towards recalcitrant compounds. The aim was consistent with the design of a process of oxidation of highly chlorinated PCBs, which is independent from their reductive dehalogenation. Feasibility was verified at a mesocosm scale and validated at pilot scale in a dynamic biopile pilot plant treating ten tons of a historically contaminated soil (9.28±0.08mg PCB/kg soil dry weight). Mixing of the SMS with the soil was required for the depletion of the contaminants. At the pilot scale, after eight months of incubation, 94.1% depletion was recorded. A positive correlation between Actinobacteria and Firmicutes active metabolism, soil laccase activity and PCB removal was observed. The SMS was found to be exploitable as a versatile low cost organic substrate capable of activating processes for the oxidation of highly chlorinated PCBs. Moreover, its exploitation as bulking agent in biopiles is a valuable management strategy for the re-utilisation of an organic waste deriving from the industrial cultivation of edible mushrooms.

Control glucémico en paciente internado / Glycemic control in inpatient / Controle glucémico en paciente internado

Resumen: La diabetes mellitus (DM) es una patología de alta prevalencia,con mayor morbimortalidad que la población general, lo que jerarquiza la importancia de obtener un buen control glucémico. Se diseñó el presente estudio con el objetivo de conocer el control metabólico de los diabéticos internados, encontrando una población en su mayoría fuera de metas terapéuticas.

Abstract: Diabetes mellitus is a high prevalence disease, with higher morbimortality than the general population, which emphasizes the importance of achieving good glycaemic control. This study was designed in order to meet the metabolic control in hospitalized diabetics, finding a population mostly out of therapeutic targets.

Resumo: La diabetes mellitus (DM) é uma patologia de alta prevalência, com prefeito morbimortalidad que a população geral, lo que jerarquiza a importância de obter um bom controle glucêmico. Se projetou o presente estudo com o objetivo de conhecer o controle metabólico dos países internos, encontrando uma população na maioria fora de metodo terapéuticas.

Spectro-electrochemical Probing of Intrinsic and Extrinsic Processes in Exciton Recombination in I-III-VI2 Nanocrystals.

Ternary CuInS2 nanocrystals (CIS NCs) are attracting attention as nontoxic alternatives to heavy metal-based chalcogenides for many technologically relevant applications. The photophysical processes underlying their emission mechanism are, however, still under debate. Here we address this problem by applying, for the first time, spectro-electrochemical methods to core-only CIS and core/shell CIS/ZnS NCs. The application of an electrochemical potential enables us to reversibly tune the NC Fermi energy and thereby control the occupancy of intragap defects involved in exciton decay. The results indicate that, in analogy to copper-doped II-VI NCs, emission occurs via radiative capture of a conduction-band electron by a hole localized on an intragap state likely associated with a Cu-related defect. We observe the increase in the emission efficiency under reductive electrochemical potential, which corresponds to raising the Fermi level, leading to progressive filling of intragap states with electrons. This indicates that the factor limiting the emission efficiency in these NCs is nonradiative electron trapping, while hole trapping is of lesser importance. This observation also suggests that the centers for radiative recombination are Cu2+ defects (preexisting and/or accumulated as a result of photoconversion of Cu1+ ions) as these species contain a pre-existing hole without the need for capturing a valence-band hole generated by photoexcitation. Temperature-controlled photoluminescence experiments indicate that the intrinsic limit on the emission efficiency is imposed by multiphonon nonradiative recombination of a band-edge electron and a localized hole. This process affects both shelled and unshelled CIS NCs to a similar degree, and it can be suppressed by cooling samples to below 100 K. Finally, using experimentally measured decay rates, we formulate a model that describes the electrochemical modulation of the PL efficiency in terms of the availability of intragap electron traps as well as direct injection of electrons into the NC conduction band, which activates nonradiative Auger recombination, or electrochemical conversion of the Cu2+ states into the Cu1+ species that are less emissive due to the need for their "activation" by the capture of photogenerated holes.