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1.
J Med Educ Curric Dev ; 11: 23821205241277334, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39246599

RESUMO

OBJECTIVES: Life-sustaining treatments (LST) aim to prolong life without reversing the underlying medical condition. Being associated with a high risk of developing unwanted adverse outcomes, decisions about LST are routinely discussed with patients at hospital admission, particularly when it comes to cardiopulmonary resuscitation. Physicians may encounter many challenges when enforcing shared decision-making in this domain. In this study, we map out how junior physicians in Southern Switzerland refer to their experiences when conducting LST discussions with hospitalized patients and their learning strategies related to this. METHODS: In this qualitative exploratory study, we conducted semi-directive interviews with junior physicians working at the regional public hospital in Southern Switzerland and analyzed them with an inductive thematic analysis. RESULTS: Nine physicians participated. We identified 3 themes: emotional burden, learning strategies and practices for conducting discussions. Participants reported feeling unprepared and often distressed when discussing LST with patients. Factors associated with emotional burden were related to the context and to how physicians developed and managed their emotions. Participants signaled having received insufficient education to prepare for discussing LST. They reported learning to discuss LST essentially through trial and error but particularly appreciated the possibility of mentoring and experiential training. Explanations that physicians gave about LST took into account patients' frequent misconceptions. Physicians reported feeling under pressure to ensure that decisions documented were medically indicated and being more at ease when patients decided by themselves to limit treatments. Communication was deemed as an important skill. CONCLUSIONS: Junior physicians experienced conducting LST discussions as challenging and felt caught between advocating for medically relevant decisions and respecting patients' autonomy. Participants reported a substantive emotional burden and feeling unprepared for this task, essentially because of a lack of adequate training. Interventions aiming to ameliorate junior physicians' competency in discussing LST can positively affect their personal experiences and decisional outcomes.

2.
Nat Commun ; 15(1): 7595, 2024 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-39217159

RESUMO

Interfacial ferroelectricity, prevalent in various parallel-stacked layered materials, allows switching of out-of-plane ferroelectric order by in-plane sliding of adjacent layers. Its resilience against doping potentially enables next-generation storage and logic devices. However, studies have been limited to indirect sensing or visualization of ferroelectricity. For transition metal dichalcogenides, there is little knowledge about the influence of ferroelectric order on their intrinsic valley and excitonic properties. Here, we report direct probing of ferroelectricity in few-layer 3R-MoS2 using reflectance contrast spectroscopy. Contrary to a simple electrostatic perception, layer-hybridized excitons with out-of-plane electric dipole moment remain decoupled from ferroelectric ordering, while intralayer excitons with in-plane dipole orientation are sensitive to it. Ab initio calculations identify stacking-specific interlayer hybridization leading to this asymmetric response. Exploiting this sensitivity, we demonstrate optical readout and control of multi-state polarization with hysteretic switching in a field-effect device. Time-resolved Kerr ellipticity reveals direct correspondence between spin-valley dynamics and stacking order.

3.
Int J Biol Macromol ; 270(Pt 1): 132208, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38723835

RESUMO

Monoclonal antibodies (mAbs) have revolutionised the biopharmaceutical market. Being proteinaceous, mAbs are prone to chemical and physical instabilities. Various approaches were attempted to stabilise proteins against degradation factors. Ionic liquids (ILs) and deep eutectic solvents (DESs) have been established as green solvents for ever-increasing pharmaceutical and biopharmaceutical applications. Hence, amino acid (AA)-based ILs, were used for the first time, for mAb stabilisation. Choline (Ch)-based DESs were also utilised for comparison purposes. The prepared ILs and DESs were utilised to stabilise Atezolizumab (Amab, anti-PDL-1 mAb). The formulations of Amab in ILs and DESs were incubated at room temperature, 45 or 55 °C. Following this, the structural stability of Amab was appraised. Interestingly, Ch-Valine retained favourable structural stability of Amab with minimal detected aggregation or degradation as confirmed by UV-visible spectroscopy and protein Mass Spectroscopy. The measured hydrodynamic diameter of Amab in Ch-Valine ranged from 10.40 to 11.65 nm. More interestingly, the anticancer activity of Amab was evaluated, and Ch-Valine was found to be optimum in retaining the activity of Amab when compared to other formulations, including the control Amab sample. Collectively, this study has spotlighted the advantages of adopting the Ch-AA ILs for the structural and functional stabilising of mAbs.


Assuntos
Aminoácidos , Anticorpos Monoclonais Humanizados , Antineoplásicos , Líquidos Iônicos , Líquidos Iônicos/química , Anticorpos Monoclonais Humanizados/química , Anticorpos Monoclonais Humanizados/farmacologia , Humanos , Antineoplásicos/química , Antineoplásicos/farmacologia , Aminoácidos/química , Coloides/química , Estabilidade de Medicamentos , Anticorpos Monoclonais/química , Anticorpos Monoclonais/farmacologia , Estabilidade Proteica , Temperatura , Linhagem Celular Tumoral , Solventes/química
4.
Naturwissenschaften ; 111(2): 15, 2024 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-38478046

RESUMO

In Earth's history warm and cold periods have alternated. Especially, during the Pleistocene, the alternation between these different climatic conditions has led to frequent range expansions and retractions of many species: while thermophilic species dispersed during warm periods, cold adapted species retracted to cold refugia and vice versa. After the last Pleistocene cycle many cold adapted taxa found refuges in relict habitats in mountain ranges. One example for such a cold adapted relict is the flightless snow fly Chionea araneoides (Dalman, 1816). It can be found in lower mountain ranges of Central Europe exclusively in stone runs and stony accumulations which provide cold microclimates. Imagines develop only in winter. They have strongly restricted ranges and hence experienced strong isolation predicting that local populations may show local adaptation and hence also genetic differentiation. We investigated this for several middle mountain ranges of Germany using the COI barcoding gene. Our analyses revealed two distinct lineages, one in the Bavarian Forest and a second one in all other more northern locations up to Scandinavia. These lineages likely go back to post-Pleistocene isolation and should be studied in more detail in the future, also to confirm the taxonomic status of both lineages. Further, we confirmed former records of the species for Germany and report new records for the federal states of Saxony, Lower Saxony, Saxony-Anhalt and Thuringia. Finally, we provide the first evidence of two types of males for the species, a small and a larger male type.


Assuntos
Dípteros , Masculino , Animais , Filogenia , Dípteros/genética , Gelo , Variação Genética , Neve
5.
Z Geburtshilfe Neonatol ; 228(3): 270-277, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38242148

RESUMO

Accidental hypothermia in mature neonates requiring hospitalization is a clinical complication that has not been studied in detail. In the present study, the effect of accidental hypothermia on common morbidity in neonates in the postnatal period was investigated. We did temperature measurements in 616 mature neonates after birth, after transfer to the maternity ward and at check-up at age of 48-72 hours of life. Additionally, nurses checked temperature until discharge at every diaper change in 302 of all included neonates who were small for gestational age (SGA) or whose mothers had green fluid or premature rupture of membranes (PROM). We investigated if there was a correlation between infection, hyperbilirubinemia, hypoglycemia, SGA, gestational diabetes, PROM, green amniotic fluid, positive GBS status of the mother, and accidental hypothermia in the first 48-72 hours of life. Mature neonates showed transient accidental hypothermia in the first 24 hours of life. No significant correlation between infection (p=0.571), hyperbilirubinemia (p=0.837), hypoglycemia (p=0.072), and accidental hypothermia could be seen. There was a significant correlation between SGA (p=0.020), PROM (p=0.008), and accidental hypothermia, while hyperthermia was associated with infection (p=0.009) and green amniotic fluid (p=0.004). SGA and PROM represent perinatal risk factors for postnatal transient accidental hypothermia in mature neonates. Increased morbidity or mortality associated with postnatal accidental hypothermia has not been demonstrated.Akzidentelle Hypothermie bei Reifgeborenen, die einer Hospitalisierung bedürfen, ist eine bisher nicht näher analysierte klinische Komplikation. In der vorliegenden Arbeit wurde die Abhängigkeit einer akzidentellen Hypothermie von typischen Erkrankungen der Postnatalperiode untersucht. Wir führten bei 616 Reifgeborenen Temperaturmessungen nach Geburt, nach Verlegung auf die Wochenstation und bei der Vorsorgeuntersuchung U2 durch. Zusätzlich kontrollierten wir bei 302 der 616 Neugeborenen mit Small for gestational age (SGA), grünem Fruchtwasser oder vorzeitigem Blasensprung (PROM) die Temperatur bei jedem Windelwechsel bis zur Entlassung. Wir untersuchten, ob es einen Zusammenhang zwischen Infektion, Hyperbilirubinämie, Hypoglykämie, SGA, Gestationsdiabetes, PROM, grünem Fruchtwasser, positivem GBS-Status der Mutter und akzidenteller Auskühlung innerhalb der ersten 48-72 Lebensstunden gab. Reifgeborene zeigten in den ersten 24 Lebensstunden transiente akzidentelle Hypothermien. Es konnte kein signifikanter Zusammenhang zwischen Infektion (P=0.571), Hyperbilirubinämie (p=0.837), Hypoglykämie (p=0.072) und akzidenteller Hypothermie festgestellt werden. Es bestand ein signifikanter Zusammenhang zwischen SGA (p=0.020), PROM (p=0.008) und akzidenteller Hypothermie, während Hyperthermie war mit Infektion (p=0.009) und grünem Fruchtwasser (p=0.004) assoziiert war. SGA und PROM stellen perinatale Risikofaktoren für postnatale transiente, akzidentelle Hypothermien bei Reifgeborenen dar. Eine erhöhte Morbidiät bzw. Mortalität im Zusammenhang mit postnataler akzidenteller Hypothermie konnte nicht nachgewiesen werden.


Assuntos
Hipotermia , Humanos , Hipotermia/mortalidade , Recém-Nascido , Feminino , Masculino , Fatores de Risco , Alemanha/epidemiologia , Mortalidade Infantil , Taxa de Sobrevida , Comorbidade , Doenças do Recém-Nascido/mortalidade , Recém-Nascido Pequeno para a Idade Gestacional
6.
Dentomaxillofac Radiol ; 53(2): 109-114, 2024 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-38180877

RESUMO

OBJECTIVES: To develop a content-aware chatbot based on GPT-3.5-Turbo and GPT-4 with specialized knowledge on the German S2 Cone-Beam CT (CBCT) dental imaging guideline and to compare the performance against humans. METHODS: The LlamaIndex software library was used to integrate the guideline context into the chatbots. Based on the CBCT S2 guideline, 40 questions were posed to content-aware chatbots and early career and senior practitioners with different levels of experience served as reference. The chatbots' performance was compared in terms of recommendation accuracy and explanation quality. Chi-square test and one-tailed Wilcoxon signed rank test evaluated accuracy and explanation quality, respectively. RESULTS: The GPT-4 based chatbot provided 100% correct recommendations and superior explanation quality compared to the one based on GPT3.5-Turbo (87.5% vs. 57.5% for GPT-3.5-Turbo; P = .003). Moreover, it outperformed early career practitioners in correct answers (P = .002 and P = .032) and earned higher trust than the chatbot using GPT-3.5-Turbo (P = 0.006). CONCLUSIONS: A content-aware chatbot using GPT-4 reliably provided recommendations according to current consensus guidelines. The responses were deemed trustworthy and transparent, and therefore facilitate the integration of artificial intelligence into clinical decision-making.


Assuntos
Inteligência Artificial , Software , Humanos , Tomada de Decisão Clínica , Tomografia Computadorizada de Feixe Cônico , Consenso
7.
Soft Matter ; 20(3): 484-494, 2024 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-37842771

RESUMO

Understanding and controlling microbial adhesion is a critical challenge in biomedical research, given the profound impact of bacterial infections on global health. Many facets of bacterial adhesion, including the distribution of adhesion forces across the cell wall, remain poorly understood. While a recent 'patchy colloid' model has shed light on adhesion in Gram-negative Escherichia coli cells, a corresponding model for Gram-positive cells has been elusive. In this study, we employ single cell force spectroscopy to investigate the adhesion force of Staphylococcus aureus. Normally, only one contact point of the entire bacterial surface is measured. However, by using a sine-shaped surface and recording force-distance curves along a path perpendicular to the rippled structures, we can characterize almost a hemisphere of one and the same bacterium. This unique approach allows us to study a greater number of contact points between the bacterium and the surface compared to conventional flat substrata. Distributed over the bacterial surface, we identify sites of higher and lower adhesion, which we call 'patchy adhesion', reminiscent of the patchy colloid model. The experimental results show that only some cells exhibit particularly strong adhesion at certain locations. To gain a better understanding of these locations, a geometric model of the bacterial cell surface was created. The experimental results were best reproduced by a model that features a few (5-6) particularly strong adhesion sites (diameter about 250 nm) that are widely distributed over the cell surface. Within the simulated patches, the number of molecules or their individual adhesive strength is increased. A more detailed comparison shows that simple geometric considerations for interacting molecules are not sufficient, but rather strong angle-dependent molecule-substratum interactions are required. We discuss the implications of our results for the development of new materials and the design and analysis of future studies.


Assuntos
Aderência Bacteriana , Staphylococcus aureus , Propriedades de Superfície , Microscopia de Força Atômica/métodos , Parede Celular , Bactérias , Coloides
8.
ACS Nano ; 17(24): 25459-25467, 2023 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-38095325

RESUMO

We report temperature-dependent spectroscopy on the layered (n = 4) two-dimensional (2D) Ruddlesden-Popper perovskite (BA)(MA)PbI. Helicity-resolved steady-state photoluminescence (PL) reveals no optical degree of polarization. Time-resolved PL shows a photocarrier lifetime on the order of nanoseconds. From simultaneously recorded time-resolved differential reflectivity (TRΔR) and time-resolved Kerr ellipticity (TRKE), a photocarrier lifetime of a few nanoseconds and a spin relaxation time on the order of picoseconds was found. This stark contrast in lifetimes clearly explains the lack of spin polarization in steady-state PL. While we observe clear temperature-dependent effects on the PL dynamics that can be related to structural dynamics, spin relaxation is nearly T-independent. Our results highlight that spin relaxation in 2D (BA)(MA)PbI occurs at time scales faster than the exciton recombination time, which poses a bottleneck for applications aiming to utilize this degree of freedom.

9.
Vet Res ; 54(1): 84, 2023 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-37773068

RESUMO

Prion diseases, including chronic wasting disease (CWD) in cervids, are fatal neurodegenerative disorders caused by the misfolding of cellular prion proteins. CWD is known to spread among captive and free-ranging deer in North America. In 2016, an outbreak of contagious CWD was detected among wild reindeer in Norway, marking the first occurrence of the disease in Europe. Additionally, new sporadic forms of CWD have been discovered in red deer in Norway and moose in Fennoscandia. We used serial protein misfolding cyclic amplification to study the ability of Norwegian prion isolates from reindeer, red deer, and moose (two isolates), as well as experimental classical scrapie from sheep, to convert a panel of 16 brain homogenates (substrates) from six different species with various prion protein genotypes. The reindeer CWD isolate successfully converted substrates from all species except goats. The red deer isolate failed to convert sheep and goat substrates but exhibited amplification in all cervid substrates. The two moose isolates demonstrated lower conversion efficacies. The wild type isolate propagated in all moose substrates and in the wild type red deer substrate, while the other isolate only converted two of the moose substrates. The experimental classical scrapie isolate was successfully propagated in substrates from all species tested. Thus, reindeer CWD and classical sheep scrapie isolates were similarly propagated in substrates from different species, suggesting the potential for spillover of these contagious diseases. Furthermore, the roe deer substrate supported conversion of three isolates suggesting that this species may be vulnerable to prion disease.


Assuntos
Cervos , Doenças das Cabras , Doenças Priônicas , Príons , Rena , Scrapie , Doenças dos Ovinos , Doença de Emaciação Crônica , Animais , Ovinos , Príons/genética , Rena/metabolismo , Doenças Priônicas/veterinária , Proteínas Priônicas/genética , Proteínas Priônicas/metabolismo , Doença de Emaciação Crônica/genética , Noruega/epidemiologia , Cabras/metabolismo
12.
BMC Surg ; 23(1): 4, 2023 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-36624485

RESUMO

BACKGROUND: Computer Assisted Design and Computer Assisted Manufacturing (CAD/CAM) have revolutionized oncologic surgery of the head and neck. A multitude of benefits of this technique has been described, but there are only few reports of donor site comorbidity following CAD/CAM surgery. METHODS: This study investigated comorbidity of the hip following deep circumflex iliac artery (DCIA) graft raising using CAD/CAM techniques. A cross-sectional examination was performed to determine range of motion, muscle strength and nerve disturbances. Furthermore, correlations between graft volume and skin incision length with postoperative donor site morbidity were assessed using Spearman's rank correlation, linear regression and analysis of variance (ANOVA). RESULTS: Fifteen patients with a mean graft volume of 21.2 ± 5.7 cm3 and a mean incision length of 228.0 ± 30.0 mm were included. Patients reported of noticeable physical limitations in daily life activities (12.3 ± 11.9 weeks) and athletic activities (38.4 ± 40.0 weeks in mean) following surgery. Graft volume significantly correlated with the duration of the use of walking aids (R = 0.57; p = 0.033) and impairment in daily life activities (R = 0.65; p = 0.012). The length of the scar of the donor-site showed a statistically significant association with postoperative iliohypogastric nerve deficits (F = 4.4, p = 0.037). Patients with anaesthaesia of a peripheral cutaneous nerve had a larger mean scar length (280 ± 30.0 mm) than subjects with hypaesthesia (245 ± 10.1 mm) or no complaints (216 ± 27.7 mm). CONCLUSIONS: Despite sophisticated planning options in modern CAD/CAM surgery, comorbidity of the donor site following  iliac graft harvesting is still a problem. This study is the first to investigate comorbidity after DCIA graft raising in a patient group treated exclusively with CAD/CAM techniques. The results indicate that a minimal invasive approach in terms of small graft volumes and small skin incisions could help to reduce postoperative symptomatology. Trial registration Retrospectively registered at the German Clinical Trials Register (DRKS-ID: DRKS00029066); registration date: 23/05/2022.


Assuntos
Cicatriz , Artéria Ilíaca , Humanos , Cicatriz/epidemiologia , Cicatriz/etiologia , Computadores , Estudos Transversais , Artéria Ilíaca/cirurgia , Mandíbula/cirurgia , Morbidade
13.
J Equine Vet Sci ; 120: 104166, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36417944

RESUMO

In gait quality assessments of horses, stride length (SL) is visually associated with spectacular movements of the front limbs, and described as ground coverage, while the movement of the hind limb under the body is supposedly essential to a longer over-tracking distance (OTD). To identify movement patterns with strong associations to SL and OTD, limb and body kinematics of 24 Franches-Montagnes (FM) stallions were measured with 3D optical motion capture (OMC) on a treadmill during an incremental speed test at trot (3.3-6.5 m/s). These measurements were correlated to the scores of ground coverage and over-tracking from six breeding experts. The amount of explained variance of parameters on SL and OTD were estimated using linear mixed-effect models in two models: a full model with all parameters measurable with OMC, and a reduced model with a subset of parameters measurable with inertial measurement units (IMUs). The front limb stance duration (16%) and OTD (7%) measured with OMC, or the OMC parameters front limb stance duration (24%) and suspension duration (14%) measurable with IMUs explained most variance in SL. However, four of six breeding experts were also significantly correlated (r>|0.41|) to front limb protraction angle. OTD variance was explained with OMC parameters suspension duration (10%) and hind limb contralateral pro-retraction angles (9%) or IMU-measurable parameters suspension duration (20%) and maximal pelvis pitch (5%). Four experts' scores for over-tracking were correlated to suspension duration. These results underscore the need for precise definitions of gait quality traits.


Assuntos
Extremidades , Marcha , Cavalos , Animais , Masculino , Membro Posterior , Fenômenos Biomecânicos
14.
Sci Rep ; 12(1): 21277, 2022 12 08.
Artigo em Inglês | MEDLINE | ID: mdl-36481750

RESUMO

It is crucial to understand why people comply with measures to contain viruses and their effects during pandemics. We provide evidence from 35 countries (Ntotal = 12,553) from 6 continents during the COVID-19 pandemic (between 2021 and 2022) obtained via cross-sectional surveys that the social perception of key protagonists on two basic dimensions-warmth and competence-plays a crucial role in shaping pandemic-related behaviors. Firstly, when asked in an open question format, heads of state, physicians, and protest movements were universally identified as key protagonists across countries. Secondly, multiple-group confirmatory factor analyses revealed that warmth and competence perceptions of these and other protagonists differed significantly within and between countries. Thirdly, internal meta-analyses showed that warmth and competence perceptions of heads of state, physicians, and protest movements were associated with support and opposition intentions, containment and prevention behaviors, as well as vaccination uptake. Our results have important implications for designing effective interventions to motivate desirable health outcomes and coping with future health crises and other global challenges.


Assuntos
COVID-19 , Humanos , COVID-19/epidemiologia , COVID-19/prevenção & controle , Estudos Transversais , Pandemias/prevenção & controle
15.
Materials (Basel) ; 15(14)2022 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-35888233

RESUMO

The development of a carbon lean steel production process following the concept of direct carbon avoidance is one of the most challenging tasks the iron and steel industry must tackle in just a few decades. The necessary drastic reduction of 80% of the process's inherent emissions by 2050 is only possible if a new process concept that uses hydrogen as the primary reductant is developed. The Hydrogen Plasma Smelting Reduction (HPSR) of ultra-fine iron ores is one of those promising concepts. The principle was already proven at a lab scale. The erection of a bench-scale facility followed this, and further scaled-ups are already planned for the upcoming years. For this scale-up, a better understanding of the fundamentals of the process is needed. In particular, knowledge of the kinetics of the process is essential for future economically feasible operations. This investigation shows the principles for evaluating and comparing the process kinetics under varying test setups by defining a representative kinetic parameter. Aside from the fundamentals for this definition, the conducted trials for the first evaluation are shown and explained. Several differences in the reduction behavior of the material at varying parameters of the process have already be shown. However, this investigation focuses on the description and definition of the method. An overall series of trials for detailed investigations will be conducted as a follow-up.

16.
Materials (Basel) ; 15(12)2022 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-35744124

RESUMO

To meet the target for anthropogenic greenhouse gas (GHG) reduction, the European steel industry is obliged to reduce its emissions. A possible pathway to reach this requirement is through developments of new technologies for a GHG-free steel production. One of these processes is the hydrogen plasma smelting reduction (HPSR) developed since 1992 at the Chair of Ferrous Metallurgy at the Montanuniversitaet Leoben in Austria. Based on the already available publication of the methodology in this work, potential process parameters were investigated that influence the reduction kinetics during continuous charging to improve the process further. Preliminary tests with different charging rates and plasma gas compositions were carried out to investigate the impacts on the individual steps of the reduction process. In the main experiments, the obtained parameters were used to determine the effect of the pre-reduction degree on the kinetics and the hydrogen conversion. Finally, the preliminary and main trials were statistically evaluated using the program MODDE® 13 Pro to identify the significant influences on reduction time, oxygen removal rate, and hydrogen conversion. High hydrogen utilization degrees could be achieved with high iron ore feeding rates and low hydrogen concentrations in the plasma gas composition. The subsequent low reduction degree and thus a high proportion of oxide melt leads to a high oxygen removal rate in the post-reduction phase and, consequently, short process times. Calculations of the reduction constant showed an average value of 1.13 × 10-5 kg oxygen/m2 s Pa, which is seven times higher than the value given in literature.

17.
Acta Vet Scand ; 64(1): 13, 2022 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-35668456

RESUMO

BACKGROUND: Chronic wasting disease (CWD) is a prion disease of cervids first reported in North America in the 1960s. In Europe, CWD was first diagnosed in 2016 in a wild reindeer in Norway. Detection of two more cases in the same mountain area led to the complete culling of this partially confined reindeer population of about 2400 animals. A total of 19 CWD positive animals were identified. The affected area is extensively used for the grazing of sheep during summers. There are many mineral licks intended for sheep in the area, but these have also been used by reindeer. This overlap in area use raised concerns for cross-species prion transmission between reindeer and sheep. In this study, we have used global positioning system (GPS) data from sheep and reindeer, including tracking one of the CWD positive reindeer, to investigate spatial and time-relevant overlaps between these two species. Since prions can accumulate in lymphoid follicles following oral uptake, samples of gut-associated lymphoid tissue (GALT) from 425 lambs and 78 adult sheep, which had grazed in the region during the relevant timeframe, were analyzed for the presence of prions. The recto-anal mucosa associated lymphoid tissue (RAMALT) from all the animals were examined by histology, immunohistochemistry (IHC) and enzyme-linked immunosorbent assay (ELISA), and the ileal Peyer's patch (IPP) from a subsample of 37 lambs were examined by histology and IHC, for the detection of prions. RESULTS: GPS data showed an overlap in area use between the infected reindeer herd and the sheep. In addition, the GPS positions of an infected reindeer and some of the sampled sheep showed temporospatial overlap. No prions were detected in the GALT of the investigated sheep even though the mean lymphoid follicle number in RAMALT and IPP samples were high. CONCLUSION: The absence of prions in the GALT of sheep that have shared pasture with CWD-infected reindeer, may suggest that transmission of this novel CWD strain to sheep does not easily occur under the conditions found in these mountains. We document that the lymphoid follicle rich RAMALT could be a useful tool to screen for prions in sheep.


Assuntos
Cervos , Príons , Rena , Doenças dos Ovinos , Doença de Emaciação Crônica , Animais , Noruega , Ovinos , Doença de Emaciação Crônica/diagnóstico , Doença de Emaciação Crônica/epidemiologia
18.
Nat Mater ; 21(4): 423-429, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35190656

RESUMO

Charge neutrality and their expected itinerant nature makes excitons potential transmitters of information. However, exciton mobility remains inaccessible to traditional optical experiments that only create and detect excitons with negligible momentum. Here, using angle-resolved photoemission spectroscopy, we detect dispersing excitons in the quasi-one-dimensional metallic trichalcogenide, TaSe3. The low density of conduction electrons and the low dimensionality in TaSe3 combined with a polaronic renormalization of the conduction band and the poorly screened interaction between these polarons and photo-induced valence holes leads to various excitonic bound states that we interpret as intrachain and interchain excitons, and possibly trions. The thresholds for the formation of a photo-hole together with an exciton appear as side valence bands with dispersions nearly parallel to the main valence band, but shifted to lower excitation energies. The energy separation between side and main valence bands can be controlled by surface doping, enabling the tuning of certain exciton properties.


Assuntos
Elétrons
19.
Transbound Emerg Dis ; 69(4): e20-e31, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34346562

RESUMO

Susceptibility of cervids to Chronic Wasting Disease (CWD), a prion disease, can be modulated by variations in the prion protein gene (PRNP), encoding the cellular prion protein (PrPC ). In prion diseases, PrPC is conformationally converted to pathogenic conformers (PrPSc ), aggregates of which comprise infectious prions. CWD has recently been observed in its contagious form in Norwegian reindeer (Rangifer tarandus) and in novel, potentially sporadic forms, here called 'atypical CWD', in moose (Alces alces) and red deer (Cervus elaphus). To estimate relative susceptibility of different Norwegian cervid species to CWD, their non-synonymous PRNP variants were analyzed. In reindeer, seven PRNP alleles were observed and in red deer and moose two alleles were present, whereas roe deer (Capreolus capreolus) PRNP was monomorphic. One 'archetypal' PRNP allele associated with susceptibility was common to all four cervid species. The distribution of PRNP alleles differed between wild and semi-domesticated reindeer, with alleles associated with a high susceptibility occurring, on average, above 55% in wild reindeer and below 20% in semi-domesticated reindeer. This difference may reflect the diverse origins of the populations and/or selection processes during domestication and breeding. Overall, PRNP genetic data indicate considerable susceptibility to CWD among Norwegian cervids and suggest that PRNP homozygosity may be a risk factor for the atypical CWD observed in moose. The CWD isolates found in the Norwegian cervid species differ from those previously found in Canada and USA. Our study provides an overview of the PRNP genetics in populations exposed to these emerging strains that will provide a basis for understanding these strains' dynamics in relation to PRNP variability.


Assuntos
Cervos , Príons , Rena , Doença de Emaciação Crônica , Animais , Cervos/genética , Noruega/epidemiologia , Proteínas Priônicas/genética , Príons/genética , Rena/genética , Doença de Emaciação Crônica/epidemiologia , Doença de Emaciação Crônica/genética
20.
Acta Vet Scand ; 63(1): 48, 2021 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-34823556

RESUMO

Prion diseases are fatal neurodegenerative disorders with known natural occurrence in humans and a few other mammalian species. The diseases are experimentally transmissible, and the agent is derived from the host-encoded cellular prion protein (PrPC), which is misfolded into a pathogenic conformer, designated PrPSc (scrapie). Aggregates of PrPSc molecules, constitute proteinaceous infectious particles, known as prions. Classical scrapie in sheep and goats and chronic wasting disease (CWD) in cervids are known to be infectious under natural conditions. In CWD, infected animals can shed prions via bodily excretions, allowing direct host-to-host transmission or indirectly via prion-contaminated environments. The robustness of prions means that transmission via the latter route can be highly successful and has meant that limiting the spread of CWD has proven difficult. In 2016, CWD was diagnosed for the first time in Europe, in reindeer (Rangifer tarandus) and European moose (Alces alces). Both were diagnosed in Norway, and, subsequently, more cases were detected in a semi-isolated wild reindeer population in the Nordfjella area, in which the first case was identified. This population was culled, and all reindeer (approximately 2400) were tested for CWD; 18 positive animals, in addition to the first diagnosed case, were found. After two years and around 25,900 negative tests from reindeer (about 6500 from wild and 19,400 from semi-domesticated) in Norway, a new case was diagnosed in a wild reindeer buck on Hardangervidda, south of the Nordfjella area, in 2020. Further cases of CWD were also identified in moose, with a total of eight in Norway, four in Sweden, and two cases in Finland. The mean age of these cases is 14.7 years, and the pathological features are different from North American CWD and from the Norwegian reindeer cases, resembling atypical prion diseases such as Nor98/atypical scrapie and H- and L-forms of BSE. In this review, these moose cases are referred to as atypical CWD. In addition, two cases were diagnosed in red deer (Cervus elaphus) in Norway. The emergence of CWD in Europe is a threat to European cervid populations, and, potentially, a food-safety challenge, calling for a swift, evidence-based response. Here, we review data on surveillance, epidemiology, and disease characteristics, including prion strain features of the newly identified European CWD agents.


Assuntos
Cervos , Príons , Scrapie , Doenças dos Ovinos , Doença de Emaciação Crônica , Animais , Europa (Continente) , Príons/genética , Ovinos , Doença de Emaciação Crônica/epidemiologia
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