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1.
Phys Rev Lett ; 132(4): 041601, 2024 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-38335367

RESUMO

We propose a two-dimensional hard-core loop-gas model as a way to regularize the asymptotically free massive continuum quantum field theory that emerges at the Berezinskii-Kosterlitz-Thouless transition. Without fine-tuning, our model can reproduce the universal step-scaling function of the classical lattice XY model in the massive phase as we approach the phase transition. This is achieved by lowering the fugacity of Fock-vacuum sites in the loop-gas configuration space to zero in the thermodynamic limit. Some of the universal quantities at the Berezinskii-Kosterlitz-Thouless transition show smaller finite size effects in our model as compared to the traditional XY model. Our model is a prime example of qubit regularization of an asymptotically free massive quantum field theory in Euclidean space-time and helps understand how asymptotic freedom can arise as a relevant perturbation at a decoupled fixed point without fine-tuning.

2.
Artigo em Inglês | MEDLINE | ID: mdl-38944413

RESUMO

Acute kidney injury is common in patients with acute decompensated heart failure. It is more common in patients with acute heart failure who suffer from chronic kidney disease. Worsening renal function is often defined as a rise in serum creatinine of more than 0.3 milligrams per deciliter (26.5 µmol/L), which by definition, is acute kidney injury stage one. Perhaps the term acute kidney injury is more appropriate than worsening renal function as it is used universally by nephrologists, internists, and other medical practitioners. In health, the heart and the kidney support each other to maintain body's homeostasis. In disease, the heart and the kidney can adversely affect each other's function causing further clinical deterioration. In patients presenting with acute heart failure and fluid overload, therapy with diuretics for decongestion often causes a rise in serum creatinine and acute kidney injury. However, in the longer term the decongestion improves survival and prevents hospital admissions despite rising serum creatinine and acute kidney injury. It is important to realize that renal venous congestion due to increased right sided heart pressures in acute heart failure is a major cause of kidney dysfunction and hence decongestion therapy improves kidney function in the longer term. This review provides a perspective on the acceptable acute kidney injury with decongestion therapy which is associated with improved survival; as opposed to acute kidney injury due to tubular injury related to sepsis or nephrotoxic drugs, which is associated with poor survival.

3.
Artigo em Inglês | MEDLINE | ID: mdl-38520170

RESUMO

BACKGROUND/HYPOTHESIS: Observational studies suggest sodium-glucose co-transporter-2 (SGLT2) inhibitor kidney outcome trials are not representative of the broader population of people with chronic kidney disease (CKD). However, there are limited data on the generalisability to those without co-existing type 2 diabetes (T2D), and the representativeness of the EMPA-KIDNEY trial has not been adequately explored. We hypothesised that SGLT2 inhibitor kidney outcome trials are more representative of people with co-existing T2D than those without, and that EMPA-KIDNEY is more representative than previous trials. METHODS: A cross-sectional analysis of adults with CKD in English primary care was conducted using the Oxford-Royal College of General Practitioners Clinical Information Digital Hub. The proportions that met the eligibility criteria of SGLT2 inhibitor kidney outcome trials were determined, and their characteristics described. Logistic regression analyses were performed to identify factors associated with trial eligibility. RESULTS: Of 6,670,829 adults, 516,491 (7.7%) with CKD were identified. In the real-world CKD population, 0.9%, 2.2%, and 8.0% met the CREDENCE, DAPA-CKD, and EMPA-KIDNEY eligibility criteria, respectively. All trials were more representative of people with co-existing T2D than those without T2D. Trial participants were 9-14 years younger than the real-world CKD population, and had more advanced CKD, including higher levels of albuminuria. A higher proportion of the CREDENCE (100%), DAPA-CKD (67.6%) and EMPA-KIDNEY (44.5%) trial participants had T2D compared to the real-world CKD population (32.8%). Renin-angiotensin system inhibitors were prescribed in almost all trial participants, compared to less than half of the real-world CKD population. Females were under-represented and less likely to be eligible for the trials. CONCLUSION: SGLT2 inhibitor kidney outcome trials represent a sub-group of people with CKD at high risk of adverse kidney events. Out study highlights the importance of complementing trials with real-world studies, exploring the effectiveness of SGLT2 inhibitors in the broader population of people with CKD.

4.
Nephrology (Carlton) ; 29(6): 325-337, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38549280

RESUMO

PURPOSE: Acute kidney injury (AKI) associated with COVID-19 is associated with poor prognosis. This study assessed the hitherto uninvestigated impact of COVID-19 on the progression and clinical outcomes of patients with AKI. METHODS: Data from 576 patients with AKI admitted between 13/3/20 and 13/5/20 were studied. Increasingly complex analyses, from logistic regressions to competing-risk and multi-state models, have revealed insights into AKI progression dynamics associated with PCR-confirmed COVID-19 acquisition and death. Meta-analyses of case fatality ratios among patients with AKI were also conducted. RESULTS: The overall case-fatality ratio was 0.33 [95% CI (0.20-0.36)]; higher in COVID-19 positive (COVID+) patients 0.52 [95% CI (0.46-0.58)] than in their negative (COVID-) counterparts 0.16 [95% CI (0.12-0.20)]. In AKI Stage-3 patients, that was 0.71 [95% CI (0.64-0.79)] among COVID+ patients with 45% dead within 14 days and 0.35 [95% CI (0.25-0.44)] in the COVID- group and 28% died within 14 days. Among patients diagnosed with AKI Stage-1 within 24 h, the probability of progression to AKI Stage-3 on day 7 post admission was 0.22 [95% CI (0.17-0.27)] among COVID+ patients, and 0.06 [95% CI (0.03, 0.09)] among those who tested negative. The probability of discharge by day 7 was 0.71 [95% CI (0.66, 0.75)] in COVID- patients, and 0.27 [95% CI (0.21, 0.32)] in COVID+ patients. By day 14, in AKI Stage-3 COVID+ patients, that was 0.35 [95% CI (0.25, 0.44)] with little change by day 10, that is, 0.38 [95% CI (0.29, 0.47)]. CONCLUSION: These results are consistent with either a rapid progression in severity, prolonged hospital care, or high case fatality ratio among AKI Stage-3 patients, significantly exacerbated by COVID-19 infection.


Assuntos
Injúria Renal Aguda , COVID-19 , Progressão da Doença , Humanos , COVID-19/complicações , COVID-19/mortalidade , COVID-19/epidemiologia , COVID-19/terapia , Injúria Renal Aguda/mortalidade , Injúria Renal Aguda/terapia , Injúria Renal Aguda/epidemiologia , Injúria Renal Aguda/diagnóstico , Masculino , Feminino , Pessoa de Meia-Idade , Idoso , SARS-CoV-2 , Fatores de Risco , Prognóstico , Estudos Retrospectivos
5.
J Acoust Soc Am ; 155(6): 3774-3781, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38860835

RESUMO

It is known that total absorption of flexural waves in a thin beam is possible through the use of monopole-dipole scatterers. In this study, we introduce a pair of identical monopole scatterers for near-total absorption of flexural waves in a thin and wide beam. Despite the two scatterers being both of the monopole type, the resonant modes of the scatterer pair exhibit monopole and dipole properties. By selecting the proper width for the beam, the two resonant modes degenerate, which leads to the total absorption. Although the beam is considerably wide, the frequency range of interest remains below the cut-on frequency of the n = 1 propagating mode, ensuring one-dimensional flexural wave propagation. Further simulations and theoretical analysis revealed that the degeneracy of the monopole and dipole modes results from their interaction with a higher-order localized flexural mode. The simulation results demonstrate absorption exceeding 99%, complemented by experimental data showing approximately 90% absorption.

6.
Pediatr Surg Int ; 40(1): 107, 2024 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-38615130

RESUMO

PURPOSE: To highlight the utility of Colorectal Nurse Specialist (CNS) supervised parental administration of rectal washouts in the management of Hirschsprung's disease (HD). METHODS: Retrospective case note review of HD patients treated at a tertiary children's hospital in United Kingdom from January 2011 to December 2022. Data collected included demographics, complications, enterocolitis, obstructive symptoms and stomas. Primary pull-through (PT) is done 8-12 weeks after birth. Parental expertise in performing rectal washouts at home is ensured by our CNS team before and after PT. RESULTS: PT was completed in 69 of 74 HD patients. Rectal washouts were attempted on 63 patients before PT. Failure of rectal washout efficacy necessitated a stoma in four patients (6.4%). Of the 65 patients who had PT and stoma closed, three (4.5%) required a further stoma over a mean follow-up period of 57 months (Range 7-144 months). Two of these had intractable diarrhoea due to Total Colonic Aganglionosis (TCA). One patient (1.5%) had unmanageable obstructive symptoms requiring re-diversion. Hirschsprung-associated enterocolitis (HAEC) requiring hospital admission occurred in 14 patients (21%). CONCLUSION: Our stoma rates are lower compared to recent UK data. This could potentially be due to emphasis on parental ability to perform effective rectal washouts at home under CNS supervision.


Assuntos
Neoplasias Colorretais , Enterocolite , Doença de Hirschsprung , Enfermeiros Especialistas , Criança , Humanos , Doença de Hirschsprung/cirurgia , Estudos Retrospectivos , Pais
7.
Phys Rev Lett ; 130(7): 071901, 2023 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-36867812

RESUMO

Matter-free lattice gauge theories (LGTs) provide an ideal setting to understand confinement to deconfinement transitions at finite temperatures, which is typically due to the spontaneous breakdown (at large temperatures) of the center symmetry associated with the gauge group. Close to the transition, the relevant degrees of freedom (Polyakov loop) transform under these center symmetries, and the effective theory depends on only the Polyakov loop and its fluctuations. As shown first by Svetitsky and Yaffe, and subsequently verified numerically, for the U(1) LGT in (2+1) dimensions, the transition is in the 2D XY universality class, while for the Z_{2} LGT, it is in the 2D Ising universality class. We extend this classic scenario by adding higher charged matter fields and show that the critical exponents γ and ν can change continuously as a coupling is varied, while their ratio is fixed to the 2D Ising value. While such weak universality is well known for spin models, we demonstrate this for LGTs for the first time. Using an efficient cluster algorithm, we show that the finite temperature phase transition of the U(1) quantum link LGT in the spin S=1/2 representation is in the 2D XY universality class, as expected. On the addition of Q=±2e charges distributed thermally, we demonstrate the occurrence of weak universality.

8.
Diabetes Obes Metab ; 25(8): 2310-2330, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37202870

RESUMO

AIM: To conduct a systematic review of observational studies to explore the real-world kidney benefits of sodium-glucose cotransporter-2 (SGLT2) inhibitors in a large and diverse population of adults with type 2 diabetes (T2D). MATERIALS AND METHODS: We searched MEDLINE, EMBASE and Web of Science for observational studies that investigated kidney disease progression in adults with T2D treated with SGLT2 inhibitors compared to other glucose-lowering therapies. Studies published from database inception to July 2022 were independently reviewed by two authors and evaluated using the Risk of Bias in Non-randomized Studies of Interventions (ROBINS-I) tool. A random-effects meta-analysis was performed on studies with comparable outcome data, reported as hazard ratios (HRs) with 95% confidence intervals (CIs). RESULTS: We identified 34 studies performed across 15 countries with a total population of 1 494 373 for inclusion. In the meta-analysis of 20 studies, SGLT2 inhibitors were associated with a 46% lower risk of kidney failure events compared with other glucose-lowering drugs (HR 0.54, 95% CI 0.47-0.63). This finding was consistent across multiple sensitivity analyses and was independent of baseline estimated glomerular filtration rate (eGFR) or albuminuria status. SGLT2 inhibitors were associated with a lower risk of kidney failure when compared with dipeptidyl peptidase-4 inhibitors and a combination of other glucose-lowering drug classes (HR 0.50, 95% CI 0.38-0.67 and HR 0.51, 95% CI 0.44-0.59, respectively). However, when compared to glucagon-like peptide 1 receptor agonists there was no statistically significant difference in the risk of kidney failure (HR 0.93, 95% CI 0.80-1.09). CONCLUSIONS: The reno-protective benefits of SGLT2 inhibitors apply to a broad population of adults with T2D treated in routine clinical practice, including those at lower risk of kidney events with normal eGFR and without albuminuria. These findings support the early use of SGLT2 inhibitors in T2D for preservation of kidney health.


Assuntos
Diabetes Mellitus Tipo 2 , Insuficiência Renal , Inibidores do Transportador 2 de Sódio-Glicose , Humanos , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/epidemiologia , Inibidores do Transportador 2 de Sódio-Glicose/uso terapêutico , Inibidores do Transportador 2 de Sódio-Glicose/farmacologia , Albuminúria/tratamento farmacológico , Rim , Insuficiência Renal/complicações , Glucose/uso terapêutico , Sódio , Hipoglicemiantes/efeitos adversos
9.
Diabet Med ; 39(4): e14769, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35080257

RESUMO

A significant percentage of people with diabetes develop chronic kidney disease and diabetes is also a leading cause of end-stage kidney disease (ESKD). The term diabetic kidney disease (DKD) includes both diabetic nephropathy (DN) and diabetes mellitus and chronic kidney disease (DM CKD). DKD is associated with high morbidity and mortality, which are predominantly related to cardiovascular disease. Hyperglycaemia is a modifiable risk factor for cardiovascular complications and progression of DKD. Recent clinical trials of people with DKD have demonstrated improvement in clinical outcomes with sodium glucose co-transporter-2 (SGLT-2) inhibitors. SGLT-2 inhibitors have significantly reduced progression of DKD and onset of ESKD and these reno-protective effects are independent of glucose lowering. At the time of this update Canagliflozin and Dapagliflozin have been approved for delaying the progression of DKD. The Association of British Clinical Diabetologists (ABCD) and UK Kidney Association (UKKA) Diabetic Kidney Disease Clinical Speciality Group have undertaken a literature review and critical appraisal of the available evidence to inform clinical practice guidelines for management of hyperglycaemia in adults with DKD. This 2021 guidance is for the variety of clinicians who treat people with DKD, including GPs and specialists in diabetes, cardiology and nephrology.


Assuntos
Diabetes Mellitus Tipo 2 , Nefropatias Diabéticas , Hiperglicemia , Insuficiência Renal Crônica , Inibidores do Transportador 2 de Sódio-Glicose , Adulto , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/terapia , Nefropatias Diabéticas/complicações , Feminino , Glucose , Humanos , Hiperglicemia/complicações , Hiperglicemia/tratamento farmacológico , Hiperglicemia/prevenção & controle , Masculino , Insuficiência Renal Crônica/complicações , Sociedades Médicas , Inibidores do Transportador 2 de Sódio-Glicose/uso terapêutico
10.
Nephrol Dial Transplant ; 37(11): 2055-2062, 2022 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-33591313

RESUMO

Chronic kidney disease (CKD) in heart failure (HF) patients is common, present in 49%, and is associated with a higher mortality hazard ratio [2.34 (95% confidence interval 2.20-2.50); P < 0.001] and multiple hospital admissions. The management of HF in CKD can be challenging due to drug-induced electrolyte and creatinine changes, resistance to diuretics and infections related to device therapy. Evidence for improvement in mortality and HF hospitalizations exists in HF with reduced ejection fraction (HFrEF) in Stage 3 CKD patients from randomized controlled trials of angiotensin-converting enzyme inhibitor (ACEi) and mineralocorticoid receptor antagonist therapy but not in dialysis patients, where higher doses can cause hyperkalaemia. Evidence of improvement in cardiovascular death and HF hospitalizations has emerged with the angiotensin receptor neprilysin inhibitor ivabradine and more recently with sodium-glucose cotransporter inhibitors in HFrEF patients with CKD Stages 1-3. However, these studies have excluded CKD Stages 4 and 5 patients. Evidence for ß-blocker therapy exists in CKD Stages 1-3 and separately in haemodialysis patients. Cardiac resynchronization therapy reduces HF hospitalizations and mortality in patients with CKD Stages 1-3 but has not been shown to do so in CKD Stages 4 and 5 or dialysis patients. Internal cardioverter and defibrillator therapy in HFrEF patients has been shown to be beneficial in CKD 3 patients but not in dialysis patients, where it is associated with high rates of infection. For HFpEF patients with CKD, therapy is symptomatic, as there is no proven therapy for improvement in survival or hospitalizations. HF patients with end-stage kidney disease with fluid overload may benefit from peritoneal dialysis. A multidisciplinary, personalized approach has been associated with better care and improved patient satisfaction.


Assuntos
Insuficiência Cardíaca , Insuficiência Renal Crônica , Humanos , Insuficiência Cardíaca/terapia , Insuficiência Cardíaca/tratamento farmacológico , Antagonistas de Receptores de Mineralocorticoides/uso terapêutico , Antagonistas de Receptores de Angiotensina/uso terapêutico , Volume Sistólico , Neprilisina , Creatinina , Ivabradina/farmacologia , Ivabradina/uso terapêutico , Diálise Renal , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Insuficiência Renal Crônica/terapia , Insuficiência Renal Crônica/tratamento farmacológico , Diuréticos/farmacologia , Receptores de Angiotensina , Glucose/farmacologia , Sódio
11.
Nephrol Dial Transplant ; 37(10): 1944-1950, 2022 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-35767848

RESUMO

BACKGROUND: Hemodialysis patients are at high risk of Covid-19, though vaccination has significant efficacy in preventing and reducing the severity of infection. Little information is available on disease severity and vaccine efficacy since the dissemination of the Omicron variant. METHODS: In a multi-center study, during a period of the epidemic driven by the Omicron variant, all hemodialysis patients positive for SARS-CoV-2 were identified. Outcomes were analyzed according to predictor variables including vaccination status. Risk of infection was analyzed using a Cox proportional hazards model. RESULTS: SARS-CoV-2 infection was identified in 1126 patients including 200 (18%) unvaccinated, 56 (5%) post first dose, 433 (38%) post second dose, and 437 (39%) at least 7 days beyond their third dose. The majority of patients had a mild course but 160 (14%) were hospitalized and 28 (2%) died. In regression models adjusted for age and comorbidity, two-dose vaccination was associated with a 39% (95%CI: 2%-62%) reduction in admissions, but third doses provided additional protection, with a 51% (95%CI: 25%-69%) further reduction in admissions. Among 1265 patients at risk at the start of the observation period, SARS-CoV-2 infection was observed in 211 (17%). Two-dose vaccination was associated with a 41% (95%CI: 3%-64%) reduction in the incidence of infection, with no clear additional effect provided by third doses. CONCLUSIONS: These data demonstrate lower incidence of SARS-CoV-2 infection after vaccination in dialysis patients during an Omicron dominant period of the epidemic. Among those developing infection, severe illness was less common with prior vaccination, particularly after third vaccine doses.


Assuntos
COVID-19 , COVID-19/epidemiologia , COVID-19/prevenção & controle , Estudos de Coortes , Humanos , Diálise Renal/efeitos adversos , SARS-CoV-2 , Vacinação
12.
BMC Nephrol ; 23(1): 268, 2022 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-35896969

RESUMO

BACKGROUND: Many people living with chronic kidney disease (CKD) are iron deficient, even though they may not be anaemic. The Iron and Muscle study aims to evaluate whether iron supplementation reduces symptoms of fatigue, improves muscle metabolism, and leads to enhanced exercise capacity and physical function. We report here the trial design and baseline characteristics. METHODS: This is a prospective, double-blind multicentre randomised controlled trial (RCT) including 75 non-dialysis stage 3-4 CKD patients with iron deficiency but without anaemia. Patients were randomly (1:1) assigned to either: i) intravenous iron therapy, or ii) placebo, with concurrent recruitment of eight CKD non-iron deficient participants and six healthy volunteers. The primary outcome of the study is the six-minute walk test (6MWT) distance between baseline and four-weeks. An additional exercise training programme for patients in both groups was initiated and completed between 4 and 12 weeks, to determine the effect of iron repletion compared to placebo treatment in the context of patients undertaking an exercise programme. Additional secondary outcomes include fatigue, physical function, muscle strength, muscle metabolism, quality of life, resting blood pressure, clinical chemistry, safety and harms associated with the iron therapy intervention and the exercise training intervention, and hospitalisations. All outcomes were conducted at baseline, 4, and 12 weeks, with a nested qualitative study, to investigate the experience of living with iron deficiency and intervention acceptability. The cohort have been recruited and baseline assessments undertaken. RESULTS: Seventy-five individuals were recruited. 44% of the randomised cohort were male, the mean (SD) age was 58 (14) years, and 56% were White. Body mass index was 31 (7) kg/m2; serum ferritin was 59 (45) µg/L, transferrin saturation was 22 (10) %, and haemoglobin was 125 (12) g/L at randomisation for the whole group. Estimated glomerular filtration rate was 35 (12) mL/min/1.73 m2 and the baseline 6MWT distance was 429 (174) m. CONCLUSION: The results from this study will address a substantial knowledge gap in the effects of intravenous iron therapy, and offer potential clinical treatment options, to improve exercise capacity, physical function, fatigue, and muscle metabolism, for non-dialysis patients with CKD who are iron-deficient but not anaemic. It will also offer insight into the potential novel effects of an 8-week exercise training programme. TRIAL REGISTRATION: EudraCT: 2018-000,144-25 Registered 28/01/2019.


Assuntos
Anemia , Deficiências de Ferro , Insuficiência Renal Crônica , Suplementos Nutricionais , Método Duplo-Cego , Tolerância ao Exercício , Fadiga , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Insuficiência Renal Crônica/complicações , Insuficiência Renal Crônica/tratamento farmacológico , Resultado do Tratamento
13.
Curr Heart Fail Rep ; 19(4): 191-199, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35704263

RESUMO

PURPOSE OF REVIEW: Heart failure (HF), in conjunction with common comorbidities such as chronic kidney disease and diabetes and medical therapies such as RAASi, predisposes to hyperkalaemia which may lead to hospitalisation and death. This paper aims to review the most current evidence surrounding the risks and management of hyperkalaemia in HF, with particular focus on recent research into RAASi including novel selective mineralocorticoid receptor blockers and novel potassium binders. RECENT FINDINGS: The most recent evidence shows that even moderate hyperkalaemia may predispose to adverse outcomes such as hospitalisation and death. Furthermore, it may prevent patients from receiving optimal medical therapy for HF by reducing prescription of RAASi therapy. Novel potassium binders such as sodium zirconium cyclosilicate (SZC) and patiromer present potential options to reduce and prevent hyperkalaemia as well as maintain optimal RAASi dosing in HF. Management of hyperkalaemia in HF has advanced in recent years. New therapies such as SZC and patiromer are contributing to the management of acute hyperkalaemia and also access to life-saving RAASi therapies by tackling and preventing hyperkalaemia in the community.


Assuntos
Insuficiência Cardíaca , Hiperpotassemia , Insuficiência Renal Crônica , Insuficiência Cardíaca/complicações , Insuficiência Cardíaca/tratamento farmacológico , Humanos , Hiperpotassemia/tratamento farmacológico , Hiperpotassemia/prevenção & controle , Antagonistas de Receptores de Mineralocorticoides/efeitos adversos , Potássio
14.
J Acoust Soc Am ; 151(3): 1722, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35364942

RESUMO

Active acoustic metamaterials incorporate electric circuit elements that input energy into an otherwise passive medium to aptly modulate the effective material properties. Here, we propose an active acoustic metamaterial with Willis coupling to drastically extend the tunability of the effective density and bulk modulus with the accessible parameter range enlarged by at least two orders of magnitude compared to that of a non-Willis metamaterial. Traditional active metamaterial designs are based on local resonances without considering the Willis coupling that limit their accessible effective material parameter range. Our design adopts a unit cell structure with two sensor-transducer pairs coupling the acoustic response on both sides of the metamaterial by detecting incident waves and driving active signals asymmetrically superimposed onto the passive response of the material. The Willis coupling results from feedback control circuits with unequal gains. These asymmetric feedback control circuits use Willis coupling to expand the accessible range of the effective density and bulk modulus of the metamaterial. The extreme effective material parameters realizable by the metamaterials will remarkably broaden their applications in biomedical imaging, noise control, and transformation acoustics-based cloaking.

15.
Pediatr Surg Int ; 38(5): 707-712, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35220458

RESUMO

PURPOSE: To determine the management and outcomes of patients with gastro-oesophageal reflux (GOR) that requires further intervention following failure of Nissen fundoplication (NF). METHODS: After institutional audit department approval, a retrospective review of paediatric patients who had further intervention following failure of primary NF between January 2006 and December 2015 for GOR at our centre was performed. Data are presented as median (range). RESULTS: Of 820 patients who underwent NF, 190 (23%) received further procedures for GOR management at a median of 21 months of age (6-186); 90/190 (47%) had gastro-jejunal feeding (GJ). Of these, 67 (74%) remained on GJ feeds up to a median of 48 months and 23/90 (26%) had a second NF after GJ feeding. 97/190 (51%) had a redo fundoplication without having had a GJ; thus, 120/190 (63%) of patients having a further procedure went on to have a second NF after a median period of 15 months (1-70 months). Three patients (2%) had early emergency wrap revision 4 days after first fundoplication (we classed this as an 'early complication'). Of the seven patients who failed a 3rd NF, 4 continued GJ feeding, 2 of had oesophagogastric dissociation; 2 had 4th NF of which 1 was successful and 1 patient had gastric pacemaker and is successfully feeding orally. Patients who were finally successfully managed with GJ underwent 2 (2-5) tube changes/year. We found patients who had a previous GJ were more likely to have failure of the redo fundoplication than those who had not to have the GJ (16/24 vs. 30/90, p = 0.005). CONCLUSION: The chance of success decreases with every further attempt at fundoplication. The only factor significantly associated with failure of redo fundoplication was whether the patient previously had a GJ tube. In patients with failed fundoplications, when symptom free on jejunal feedings, further anti-reflux surgical intervention should be avoided. A randomized prospective study is needed for patient selection.


Assuntos
Refluxo Gastroesofágico , Laparoscopia , Criança , Fundoplicatura/métodos , Refluxo Gastroesofágico/etiologia , Refluxo Gastroesofágico/cirurgia , Humanos , Laparoscopia/métodos , Recidiva , Reoperação , Estudos Retrospectivos
16.
Kidney Int ; 100(6): 1170-1173, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34802558

RESUMO

Fluid overload is a common and important complication encountered in the care of patients with end-stage kidney failure receiving hemodialysis. Fluid overload not only causes unpleasant symptomatology for patients on dialysis, but also leads to increased incidence of hospitalization and mortality. Given the association of fluid overload with adverse outcomes in patients with end-stage kidney failure on hemodialysis, it is paramount that we identify effective and reliable methods to determine fluid status in such patients.


Assuntos
Insuficiência Cardíaca , Falência Renal Crônica , Desequilíbrio Hidroeletrolítico , Hospitalização , Humanos , Falência Renal Crônica/complicações , Falência Renal Crônica/terapia , Diálise Renal/efeitos adversos , Desequilíbrio Hidroeletrolítico/etiologia , Desequilíbrio Hidroeletrolítico/terapia
17.
Phys Rev Lett ; 126(22): 220601, 2021 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-34152190

RESUMO

We consider the spectrum of a U(1) quantum link model where gauge fields are realized as S=1/2 spins and demonstrate a new mechanism for generating quantum many-body scars (high-energy eigenstates that violate the eigenstate thermalization hypothesis) in a constrained Hilbert space. Many-body dynamics with local constraints has attracted much attention due to the recent discovery of nonergodic behavior in quantum simulators based on Rydberg atoms. Lattice gauge theories provide natural examples of constrained systems since physical states must be gauge invariant. In our case, the Hamiltonian H=O_{kin}+λO_{pot}, where O_{pot} (O_{kin}) is diagonal (off-diagonal) in the electric flux basis, contains exact midspectrum zero modes at λ=0 whose number grows exponentially with system size. This massive degeneracy is lifted at any nonzero λ but some special linear combinations that simultaneously diagonalize O_{kin} and O_{pot} survive as quantum many-body scars, suggesting an "order-by-disorder" mechanism in the Hilbert space. We give evidence for such scars and show their dynamical consequences on two-leg ladders with up to 56 spins, which may be tested using available proposals of quantum simulators. Results on wider ladders point towards their presence in two dimensions as well.

18.
Diabet Med ; 38(6): e14523, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33434362

RESUMO

Post-transplant diabetes mellitus (PTDM) is common after solid organ transplantation (SOT) and associated with increased morbidity and mortality for allograft recipients. Despite the significant burden of disease, there is a paucity of literature with regards to detection, prevention and management. Evidence from the general population with diabetes may not be translatable to the unique context of SOT. In light of emerging clinical evidence and novel anti-diabetic agents, there is an urgent need for updated guidance and recommendations in this high-risk cohort. The Association of British Clinical Diabetologists (ABCD) and Renal Association (RA) Diabetic Kidney Disease Clinical Speciality Group has undertaken a systematic review and critical appraisal of the available evidence. Areas of focus are; (1) epidemiology, (2) pathogenesis, (3) detection, (4) management, (5) modification of immunosuppression, (6) prevention, and (7) PTDM in the non-renal setting. Evidence-graded recommendations are provided for the detection, management and prevention of PTDM, with suggested areas for future research and potential audit standards. The guidelines are endorsed by Diabetes UK, the British Transplantation Society and the Royal College of Physicians of London. The full guidelines are available freely online for the diabetes, renal and transplantation community using the link below. The aim of this review article is to introduce an abridged version of this new clinical guideline ( https://abcd.care/sites/abcd.care/files/site_uploads/Resources/Position-Papers/ABCD-RA%20PTDM%20v14.pdf).


Assuntos
Diabetes Mellitus/etiologia , Medicina Interna , Nefrologia , Transplante de Órgãos/efeitos adversos , Complicações Pós-Operatórias/terapia , Guias de Prática Clínica como Assunto , Sociedades Médicas , Diabetes Mellitus/epidemiologia , Diabetes Mellitus/terapia , Humanos , Terapia de Imunossupressão/métodos , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia
19.
BMC Nephrol ; 22(1): 254, 2021 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-34229607

RESUMO

BACKGROUND: CKD is common in heart failure (HF) and associated with morbidity and mortality, yet life-prolonging medications such as renin-angiotensin-aldosterone inhibitors (RAASi) are underused due to risk of hyperkalaemia. Sodium zirconium cyclosilicate (SZC) is a potassium-binding medication that has been shown to reduce incidence of hyperkalaemia in CKD, non-CKD, and HF populations, which we propose will support maximisation of RAASi therapy. METHODS: We propose a 1:1 randomised, double-blind, placebo-controlled trial in which participants will receive either SZC or placebo. We will up-titrate participants' RAASi therapy while monitoring their serum potassium levels and adjusting their SZC dose if necessary. Participants with CKD and HF will be recruited from CKD and HF clinics at St George's Hospital. The total study period will be 18 months; 130 participants will be enrolled for approximately two months each following screening. Our primary outcome will be the proportion of participants who achieve maximum RAASi dose while maintaining normokalaemia. Secondary outcomes include participants reaching maximum RAASi dose without severe hyperkalaemia; time from randomisation to hyperkalaemia; time from randomisation to severe hyperkalaemia; number of RAASi dose escalations per participant; final doses of RAASi therapy; changes in quality of life score, eGFR, ACR, serum sodium, troponin T; number and duration of hospital admissions; and within-participant change in serum potassium compared to baseline. DISCUSSION: This trial will be the first to examine the use of SZC for the maximisation of RAASi dosing in patients with advanced CKD and HF. We will assess the impact of achieving target RAASi dosing on hospital admission rates and duration of stay, with the hope that optimum RAASi treatment will translate into reduced morbidity and improved QoL. If clinical benefit is demonstrated, we hope that the joint multidisciplinary CKD-HF approach will be expanded. TRIAL REGISTRATION: EudraCT number 2020-002946-18. Registered on 08 June 2020. Online record pending.


Assuntos
Insuficiência Cardíaca/complicações , Hiperpotassemia/prevenção & controle , Resinas de Troca Iônica/uso terapêutico , Insuficiência Renal Crônica/complicações , Insuficiência Renal Crônica/tratamento farmacológico , Sistema Renina-Angiotensina/efeitos dos fármacos , Silicatos/uso terapêutico , Antagonistas de Receptores de Angiotensina/administração & dosagem , Antagonistas de Receptores de Angiotensina/uso terapêutico , Inibidores da Enzima Conversora de Angiotensina/administração & dosagem , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Método Duplo-Cego , Humanos , Antagonistas de Receptores de Mineralocorticoides/administração & dosagem , Antagonistas de Receptores de Mineralocorticoides/uso terapêutico , Insuficiência Renal Crônica/fisiopatologia
20.
Kidney Int ; 97(6): 1076-1082, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32354637

RESUMO

By 21 March 2020 infections related to the novel coronavirus SARS-CoV-2 had affected people from 177 countries and caused 11,252 reported deaths worldwide. Little is known about risk, presentation and outcomes of SARS-CoV-2 (COVID-19) infection in kidney transplantation recipients, who may be at high-risk due to long-term immunosuppression, comorbidity and residual chronic kidney disease. Whilst COVID-19 is predominantly a respiratory disease, in severe cases it can cause kidney and multi-organ failure. It is unknown if immunocompromised hosts are at higher risk of more severe systemic disease. Therefore, we report on seven cases of COVID-19 in kidney transplant recipients (median age 54 (range 45-69), three females, from a cohort of 2082 managed transplant follow-up patients) over a six-week period in three south London hospitals. Two of seven patients presented within three months of transplantation. Overall, two were managed on an out-patient basis, but the remaining five required hospital admission, four in intensive care units. All patients displayed respiratory symptoms and fever. Other common clinical features included hypoxia, chest crepitation, lymphopenia and high C-reactive protein. Very high D dimer, ferritin and troponin levels occurred in severe cases and likely prognostic. Immunosuppression was modified in six of seven patients. Three patients with severe disease were diabetic. During a three week follow up one patient recovered, and one patient died. Thus, our findings suggest COVID-19 infection in kidney transplant patients may be severe, requiring intensive care admission. The symptoms are predominantly respiratory and associated with fever. Most patients had their immunosuppression reduced and were treated with supportive therapy.


Assuntos
Betacoronavirus/patogenicidade , Infecções por Coronavirus/epidemiologia , Febre/epidemiologia , Terapia de Imunossupressão/efeitos adversos , Transplante de Rim/efeitos adversos , Pneumonia Viral/epidemiologia , Idoso , Betacoronavirus/imunologia , Betacoronavirus/isolamento & purificação , COVID-19 , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/virologia , Feminino , Febre/diagnóstico , Febre/imunologia , Febre/virologia , Seguimentos , Rejeição de Enxerto/imunologia , Rejeição de Enxerto/prevenção & controle , Humanos , Hospedeiro Imunocomprometido/imunologia , Masculino , Pessoa de Meia-Idade , Pandemias , Pneumonia Viral/diagnóstico , Pneumonia Viral/imunologia , Pneumonia Viral/virologia , SARS-CoV-2 , Índice de Gravidade de Doença , Transplantados/estatística & dados numéricos
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