Tendon proper- and peritenon-derived progenitor cells have unique tenogenic properties.

IntroductionMultipotent progenitor populations exist within the tendon proper and peritenon of the Achilles tendon. Progenitor populations derived from the tendon proper and peritenon are enriched with distinct cell types that are distinguished by expression of markers of tendon and vascular or pericyte origins, respectively. The objective of this study was to discern the unique tenogenic properties of tendon proper- and peritenon-derived progenitors within an in vitro model. We hypothesized that progenitors from each region contribute differently to tendon formation; thus, when incorporated into a regenerative model, progenitors from each region will respond uniquely. Moreover, we hypothesized that cell populations like progenitors were capable of stimulating tenogenic differentiation, so we generated conditioned media from these cell types to analyze their stimulatory potentials.MethodsIsolated progenitors were seeded within fibrinogen/thrombin gel-based constructs with or without supplementation with recombinant growth/differentiation factor-5 (GDF5). Early and late in culture, gene expression of differentiation markers and matrix assembly genes was analyzed. Tendon construct ultrastructure was also compared after 45 days. Moreover, conditioned media from tendon proper-derived progenitors, peritenon-derived progenitors, or tenocytes was applied to each of the three cell types to determine paracrine stimulatory effects of the factors secreted from each of the respective cell types.ResultsThe cell orientation, extracellular domain and fibril organization of constructs were comparable to embryonic tendon. The tendon proper-derived progenitors produced a more tendon-like construct than the peritenon-derived progenitors. Seeded tendon proper-derived progenitors expressed greater levels of tenogenic markers and matrix assembly genes, relative to peritenon-derived progenitors. However, GDF5 supplementation improved expression of matrix assembly genes in peritenon progenitors and structurally led to increased mean fibril diameters. It also was found that peritenon-derived progenitors secrete factor(s) stimulatory to tenocytes and tendon proper progenitors.ConclusionsData demonstrate that, relative to peritenon-derived progenitors, tendon proper progenitors have greater potential for forming functional tendon-like tissue. Furthermore, factors secreted by peritenon-derived progenitors suggest a trophic role for this cell type as well. Thus, these findings highlight the synergistic potential of including these progenitor populations in restorative tendon engineering strategies

Empirical Research on Financial Notes to the Accounts and Earnings Management

Managers can influence the amount of net income their firm reports by variation in the application of accounting policies or by making real cash flow decisions. 'Earnings management' is the term given when such choices or decisions distort the fair presentation of earnings. Such earnings management activities can lead to negative consequences in the long-term. Accounting scandals in the past have shown that earnings management can even threaten the existence of a firm. Therefore, it is of crucial importance to detect and restrict earnings management. The notes to the accounts can provide information, which is otherwise not presented on the face of the financial statements. Especially the accounting policy disclosures improve the understanding about a firm’s current and future earnings. According to the comparability theory, there should be comparable accountings of firms in the same industry that are subject to similar economic events. Extending this theory, managers of comparable firms should translate the same economic events into similar notes to the accounts and contain similar earnings and discretionary accruals. Therefore, this PhD thesis examines whether similar notes to the accounts are negatively associated with a firm’s propensity to manage earnings. This means that the effect of similar textual accounting policy disclosures or rather notes relative to other firms in the same industry is tested on both, accrual-based and real earnings management proxies. This research uses detail-tagged XBRL notes from SEC EDGAR system as data source. To operationalize the within-industry similarity of the XBRL-formatted notes, the co-sine similarity measure was utilized in this study. Two different similarity scores of the notes are adopted. First, the full set of accounting policy disclosures and second, the revenue recognition disclosures. The key findings demonstrate that firms with more similar notes of the previous year conduct less accrual-based earnings management activities in the following fiscal year. Also, the empirical analyses show that more similar accounting policy and revenue recognition disclosures are negatively associated with real earnings management activities. Collectively, these results indicate that firms with an overall better accounting information environment as measured by more similar notes, relative to industry peers, engage in less accrual-based and real earnings management activities in the following year

The Impact of Distributed Energy Resources on the Bulk Power System: A Deeper Dive

solar photovoltaics (PV), electric storage and electric \ vehicles, demand response, combined heat and \ power, wind, fuel cells, and micro-turbines are \ typically installed on the low or medium voltage \ distribution network. Changes on the distribution \ network can have rippling effects throughout the rest \ of the power system. In this paper, we have \ calculated both traditional locational marginal \ prices (LMPs) and distributed locational marginal \ prices (DLMPs) using an optimal power flow (DC \ OPF). This paper provides an analysis of the energy \ price impacts resulting from significant additions of \ Distributed Energy Resources (DER), namely solar \ PV, electric batteries and demand response, in a \ distribution feeder. The impact is measured in terms \ of nodal approximations to DLMPs, realistic \ calculation of LMPs in the transmission system and \ overall price suppression effects that trickle down to \ consumers on the feeder. Policy implications are \ drawn concerning the potential impacts of \ penetration of DER on future planning, and \ operation of the power system as well as on energy \ markets and the environment

Photon-statistics force in ultrafast electron dynamics

In strong-field physics and attosecond science, intense light induces ultrafast electron dynamics. Such ultrafast dynamics of electrons in matter is at the core of phenomena such as high harmonic generation (HHG), where these dynamics lead to emission of extreme UV bursts with attosecond duration. So far, all ultrafast dynamics of matter were understood to originate purely from the classical vector potential of the driving light, disregarding the influence of the quantum nature of light. Here we show that dynamics of matter driven by bright (intense) light significantly depend on the quantum state of the driving light, which induces an effective photon-statistics force. To provide a unified framework for the analysis & control over such a force, we extend the strong-field approximation (SFA) theory to account for non-classical driving light. Our quantum SFA (qSFA) theory shows that in HHG, experimentally feasible squeezing of the driving light can shift & shape electronic trajectories and attosecond pulses at the scale of hundreds of attoseconds. Our work presents a new degree-of-freedom for attosecond spectroscopy, by relying on nonclassical electromagnetic fields, and more generally, introduces a direct connection between attosecond science and quantum optics

Generation of squeezed high-order harmonics

For decades, most research on high harmonic generation (HHG) considered matter as quantum but light as classical, leaving the quantum-optical nature of the harmonics an open question. Here we explore the quantum properties of high harmonics. We derive a formula for the quantum state of the high harmonics, when driven by arbitrary quantum light states, and then explore specific cases of experimental relevance. Specifically, for a moderately squeezed pump, HHG driven by squeezed coherent light results in squeezed high harmonics. Harmonic squeezing is optimized by syncing ionization times with the pump's squeezing phase. Beyond this regime, as pump squeezing is increased, the harmonics initially acquire squeezed thermal photon statistics, and then occupy an intricate quantum state which strongly depends on the semi-classical nonlinear response function of the interacting system. Our results pave the way for the generation of squeezed extreme-ultraviolet ultrashort pulses, and, more generally, quantum frequency conversion into previously inaccessible spectral ranges, which may enable ultrasensitive attosecond metrology