There is little research on how consumers decide whether they want to use algorithmic advice or not. In this research, we show that consumers’ lay beliefs about artificial intelligence (AI) serve as ...a heuristic cue to evaluate accuracy of algorithmic advice in different professional service domains. Three studies provide robust evidence that consumers who believe that AI is higher than human intelligence are more likely to adopt algorithmic advice. We also demonstrate that lay beliefs about AI only influence adoption of algorithmic advice when a decision task is perceived to be complex.
•We explore the effects of introducing algorithmic advice to existing customers.•Algorithmic advice has different effects across different customer relationships.•Exchange-oriented customers respond ...more positively to algorithmic advice.•Communally-oriented customers respond more negatively to algorithmic advice.•Offering a human fallback option has different effects across relationship types.
An increasing number of service firms are introducing algorithmic advice to their customers. In this research, we examine the introduction of such tools from a relational perspective and show that the type of relationship a customer has with a service firm moderates his or her response to algorithmic advice. Studies 1 and 2 find that customers in communal relationships are more reluctant to use algorithmic advice instead of human advice than customers in exchange relationships. Study 3 shows that offering customers algorithmic advice may harm communal relationships but not exchange relationships. Building on these findings, Studies 4, 5, and 6 examine how firms can mitigate the potentially negative relational consequences of algorithmic advice. While a fallback option that signals that customers can request additional human advice if needed is effective in preventing relational damages in communal relationships, this same intervention backfires in exchange relationships. These findings have important implications by showing that managers need to consider the relational consequences of introducing algorithmic advice to existing customers.
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Summary Background People with chronic tetraplegia, due to high-cervical spinal cord injury, can regain limb movements through coordinated electrical stimulation of peripheral muscles and nerves, ...known as functional electrical stimulation (FES). Users typically command FES systems through other preserved, but unrelated and limited in number, volitional movements (eg, facial muscle activity, head movements, shoulder shrugs). We report the findings of an individual with traumatic high-cervical spinal cord injury who coordinated reaching and grasping movements using his own paralysed arm and hand, reanimated through implanted FES, and commanded using his own cortical signals through an intracortical brain–computer interface (iBCI). Methods We recruited a participant into the BrainGate2 clinical trial, an ongoing study that obtains safety information regarding an intracortical neural interface device, and investigates the feasibility of people with tetraplegia controlling assistive devices using their cortical signals. Surgical procedures were performed at University Hospitals Cleveland Medical Center (Cleveland, OH, USA). Study procedures and data analyses were performed at Case Western Reserve University (Cleveland, OH, USA) and the US Department of Veterans Affairs, Louis Stokes Cleveland Veterans Affairs Medical Center (Cleveland, OH, USA). The study participant was a 53-year-old man with a spinal cord injury (cervical level 4, American Spinal Injury Association Impairment Scale category A). He received two intracortical microelectrode arrays in the hand area of his motor cortex, and 4 months and 9 months later received a total of 36 implanted percutaneous electrodes in his right upper and lower arm to electrically stimulate his hand, elbow, and shoulder muscles. The participant used a motorised mobile arm support for gravitational assistance and to provide humeral abduction and adduction under cortical control. We assessed the participant's ability to cortically command his paralysed arm to perform simple single-joint arm and hand movements and functionally meaningful multi-joint movements. We compared iBCI control of his paralysed arm with that of a virtual three-dimensional arm. This study is registered with ClinicalTrials.gov , number NCT00912041. Findings The intracortical implant occurred on Dec 1, 2014, and we are continuing to study the participant. The last session included in this report was Nov 7, 2016. The point-to-point target acquisition sessions began on Oct 8, 2015 (311 days after implant). The participant successfully cortically commanded single-joint and coordinated multi-joint arm movements for point-to-point target acquisitions (80–100% accuracy), using first a virtual arm and second his own arm animated by FES. Using his paralysed arm, the participant volitionally performed self-paced reaches to drink a mug of coffee (successfully completing 11 of 12 attempts within a single session 463 days after implant) and feed himself (717 days after implant). Interpretation To our knowledge, this is the first report of a combined implanted FES+iBCI neuroprosthesis for restoring both reaching and grasping movements to people with chronic tetraplegia due to spinal cord injury, and represents a major advance, with a clear translational path, for clinically viable neuroprostheses for restoration of reaching and grasping after paralysis. Funding National Institutes of Health, Department of Veterans Affairs.
Abstract Background context Degeneration and injuries of the intervertebral disc (IVD) result in large alterations in biomechanical behaviors. Repair strategies using biomaterials can be optimized ...based on the biomechanical and biological requirements of the IVD. Purpose To review the present literature on the effects of degeneration, simulated degeneration, and injury on biomechanics of the IVD, with special attention paid to needle puncture injuries, which are a pathway for diagnostics and regenerative therapies and the promising biomaterials for disc repair with a focus on how those biomaterials may promote biomechanical repair. Study design A narrative review to evaluate the role of biomechanics on disc degeneration and regenerative therapies with a focus on what biomechanical properties need to be repaired and how to evaluate and accomplish such repairs using biomaterials. Model systems for the screening of such repair strategies are also briefly described. Methods Articles were selected from two main PubMed searches using keywords: intervertebral AND biomechanics (1,823 articles) and intervertebral AND biomaterials (361 articles). Additional keywords (injury, needle puncture, nucleus pressurization, biomaterials, hydrogel, sealant, tissue engineering) were used to narrow the articles down to the topics most relevant to this review. Results Degeneration and acute disc injuries have the capacity to influence nucleus pulposus (NP) pressurization and annulus fibrosus (AF) integrity, which are necessary for an effective disc function and, therefore, require repair. Needle injection injuries are of particular clinical relevance with the potential to influence disc biomechanics, cellularity, and metabolism, yet these effects are localized or small and more research is required to evaluate and reduce the potential clinical morbidity using such techniques. NP replacement strategies, such as hydrogels, are required to restore the NP pressurization or the lost volume. AF repair strategies including cross-linked hydrogels, fibrous composites, and sealants offer promise for regenerative therapies to restore AF integrity. Tissue engineered IVD structures, as a single implantable construct, may promote greater tissue integration due to the improved repair capacity of the vertebral bone. Conclusions IVD height, neutral zone characteristics, and torsional biomechanics are sensitive to specific alterations in the NP pressurization and AF integrity and must be addressed for an effective functional repair. Synthetic and natural biomaterials offer promise for NP replacement, AF repair, as an AF sealant, or whole disc replacement. Meeting mechanical and biological compatibilities are necessary for the efficacy and longevity of the repair.
Abstract
While Parkinson's disease (PD)-related neurodegeneration is associated with structural changes in the brain, conventional magnetic resonance imaging (MRI) has proven less effective for ...clinical diagnosis due to its inability to reliably identify subtle changes early in the disease course. In this study, we aimed to develop a structural MRI-based biomarker to predict the rate of progression of motor symptoms in the early stages of PD. The study included 88 patients with PD and 120 healthy controls from the Parkinson's Progression Markers Initiative database; MRI at baseline and motor symptom scores assessed using the MDS-UPDRS-III at two time points (baseline and 48 months) were selected. Group-level volumetric analyses at baseline were not associated with the decline in motor functioning. Then, we developed a patient-specific multivariate gray matter volumetric distance and demonstrated that it could significantly predict changes in motor symptom scores (
P
< 0.05). Further, we classified patients as relatively slower and faster progressors with 89% accuracy using a support vector machine classifier. Thus, we identified a promising structural MRI-based biomarker for predicting the rate of progression of motor symptoms and classifying patients based on motor symptom severity.
The significance of magnesium isotope (δ26Mg) fractionation in the continental hydrothermal domain is poorly explored. Here, a detailed Mg isotope dataset from various aquifer host rocks and ...corresponding hydrothermal carbonate precipitates from the Schwarzwald mining area in SW Germany is documented and discussed. This study is motivated by the very considerable existing data set on hydrothermal mineralizations in the study area and the excellent regional control of sampling points. Based on structural, mineralogical and microthermometrical arguments, we here subdivide three clusters of veins: (i) Permian, (ii) Jurassic–Cretaceous and (iii) post-Cretaceous (Cenozoic). The focus is on clusters ii and iii and their corresponding, texturally older hydrothermal fluid inclusion-rich, coarse-grained, low-Mg calcite and dolomite–ankerite solid solutions and younger, oscillatory zoned low-Mg calcite and dolomite–ankerite solid solution crystals precipitated from fluids with temperatures between 50 and 350°C. In terms of their δ26Mg ratios, three characteristic groups of hydrothermal carbonates can be distinguished: (i) Jurassic–Cretaceous veins (δ26Mg=−3.38 to −0.82‰) in the central Schwarzwald precipitated from fluids containing a significant proportion of sedimentary cover-derived waters. They yield 26Mg-depleted Mg isotope signatures typical of sedimentary carbonate lithologies. (ii) Jurassic–Cretaceous vein carbonates in the southern Schwarzwald precipitated from mainly basement-derived fluids with 26Mg-enriched signatures (δ26Mg=−1.22 to +0.05‰). Supporting evidence for the origin of these fluids comes from Sr–C–Pb isotope systematics and trace element compositional variations of fahlore and sphalerite. The Mg isotope variations are controlled by differences in fluid source characteristics dominate over variations exerted by mineralogical differences (where low-Mg calcites are generally, but not in all cases, more depleted in 26Mg compared to dolomite–ankerite solid solutions). (iii) Post-Cretaceous (Cenozoic), Rhinegraben-related veins represent a complex tectonic juxtaposition of different aquifer lithologies. As expected, this phase spans the full range from silicate to carbonate Mg isotope signatures (+0.45 to −3.4‰). Magnesium isotope data are supported by textural analyses (optical and cathodoluminescence microscopy), electron microprobe, microthermometry and published radiogenic 87Sr/86Sr isotope systematics. Our data are not in agreement with a significant temperature-controlled Δ26Mgfluid-calcite and no obvious relation between fluid salinity and hydrothermal carbonate δ26Mg is found. The results of this study suggest that hydrothermal carbonate magnesium isotope ratios have a significant potential as tracer of hydrothermal fluid sources and corresponding aquifer lithologies.
•First magnesium isotope data of hydrothermal continental carbonates in ore deposits•Magnesium isotope systematics in context of microthermometrical data (salinity, temperature)•Magnesium isotope systematics in context of different continental fluid aquifers•Magnesium isotope systematics in combination with detailed textural classification of the samples•Magnesium isotope data as source/aquifer tracer for hydrothermal fluids
Chronic inflammation is an important component of intervertebral disc (IVD) degeneration, but there is limited knowledge about the identity and source of inflammatory cells involved with the ...degenerative processes. Macrophages can exhibit multiple phenotypes and are known inflammatory regulators in many tissues, but their phenotypes have not been characterized in IVD degeneration.
We aimed to characterize accumulation and localization of macrophages in IVD degeneration.
This is an exploratory study to characterize macrophage phenotypes in human cadaver IVDs and the effects of injury and degeneration using multiple immunohistochemistry methods.
Percent positivity of immunohistochemical markers specific for CCR7, CD163, and CD206, and qualitative assessments of dual immunofluorescence and immunostaining localization were the outcome measures.
Macrophages were identified in human cadaveric IVDs with immunohistochemistry using cell surface markers CCR7, CD163, and CD206, which are associated with proinflammatory M1, remodeling M2c, and anti-inflammatory M2a phenotypes, respectively. Variations in the accumulation and localization of macrophage markers with degenerative grade across subjects and within donors are described.
Cells expressing all three macrophage markers were found in all degenerative IVDs, but not in the healthiest IVDs. Cells expressing CCR7 and CD163, but not CD206, significantly increased with degenerative grade. Many cells also co-expressed multiple macrophage markers. Across all degenerative grades, CCR7+ and CD163+ were significantly more present in unhealthy nucleus pulposus (NP), annulus fibrosus (AF), and end plate (EP) regions exhibiting structural irregularities and defects. Positively stained cells in the NP and AF closely resembled resident IVD cells, suggesting that IVD cells can express macrophage cell surface markers. In the EP, there were increasing trends of positively stained cells with atypical morphology and distribution, suggesting a source for exogenous macrophage infiltration into the IVD.
Chronic inflammatory conditions of IVD degeneration appear to involve macrophages or macrophage-like cells, as expression of multiple macrophage markers increased with degeneration, especially around unhealthy regions with defects and the EP. Knowledge of macrophage phenotypes and their localization better elucidates the complex injury and repair processes in IVDs and may eventually lead to novel treatments.
The temporal evolution of fracture networks below hydrothermal veins (root zones) and their impact on fluid chemistry, vein mineralogy and ore formation is insufficiently understood for ...unconformity-related hydrothermal veins in regions of extension, such as the common epithermal sediment-, unconformity- and basement-hosted Pb–Zn deposits. As metals and other trace elements are presumably mobilized during water–rock interaction of highly saline brines with igneous and metamorphic basement rocks, the evolution of these fracture zones seems to play a major role for hydrothermal ore formation. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICPMS) microanalysis of individual, texturally well-characterized fluid inclusions, hosted in fluorite and quartz of the Jurassic–Cretaceous Brandenberg fluorite–barite–quartz–galena–sphalerite vein near Todtnau, Schwarzwald, SW Germany, was carried out. Fluid mobile elements (Rb, Cs, Li, W, Ba, Zn, Pb, Sr), preferentially released by the alteration of primary rock-forming minerals (process tracer) were analysed as well as the Cl/Br ratio (source tracer) of fluid inclusions in genetically early fluorite and later quartz. A distinct decrease of trace elements within the fluid inclusions with time indicates successive alteration of primary minerals at the fracture wall to clay minerals with consecutive fluid pulses. A maximum concentration of trace elements in the fluid and consequent ore precipitation is associated with the initial phase of formation of a fracture root. Later fluid pulses migrate along pre-existing fractures so that the amount of fresh reactive rock material decreases with each fluid pulse. As a consequence, multiple generations of ore minerals require the formation of new fracture branches in the root zone of hydrothermal veins. Therefore, it seems that cataclastic zones below hydrothermal veins essentially control ore formation, and their tectonically induced dynamics might be one key parameter that governs the temporal interval of ore precipitation.
•Temporarily and spatially resolved LA-ICPMS study of individual fluid inclusions•Temporal and chemical evolution of fracture root zones below hydrothermal veins•The evolution of dynamic fracture systems shows distinct cyclicality in their fluid chemistry.•Ore deposition, primarily occurs at the beginning of these cycles.•Ore formation is promoted by dynamic fracture systems, in which new fracture branches are established abundantly.
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