Horticultural Characterization of Wild Hydrangea quercifolia Seedlings Collected Throughout the Species Native Range

Oakleaf hydrangea (Hydrangea quercifolia Bartr.) is an understory shrub native to the southeastern United States. Hydrangeas are popular ornamental landscape plants; however, little is known about the diversity in horticulturally important traits for oakleaf hydrangea. Information regarding the variation in important traits could guide future breeding efforts for the species. Seed was collected from 55 populations throughout the range of the species for the purpose of conducting a horticultural characterization of the species compared with select cultivars. Plant architecture was characterized as plant height, number of nodes, internode length, number of branches, and plant width. Plant architecture was measured for container-grown and field-grown plants in two locations (Minnesota and Tennessee). Tolerance to leaf spot (Xanthomonas campestris L.) was characterized for wild-collected seedlings and cultivars by measuring disease severity under exposure to ambient inoculum. Cold hardiness was characterized during two winters with a controlled freezing experiment. During the first winter, seedlings were tested in January; during the second winter, seedlings and cultivars were tested monthly from October through April. Plant architecture varied by environment, with plants growing larger in Tennessee than in Minnesota. The heights of container-grown and field-grown plants were correlated with the collection site latitude (r = −0.66), with populations from the northeastern extent of the range of the species being the most compact, and populations from Florida being the tallest. Leaf spot severity varied significantly among populations and cultivars and was also correlated with latitude for the seedlings (r = 0.70). Two populations in Florida were identified as sources of high tolerance to leaf spot, whereas ‘Flemygea’ and ‘Alice’ were identified as having moderate tolerance to leaf spot. Cold hardiness varied among populations and cultivars and among months of the winter. The overall maximum cold hardiness was observed in February [mean lethal temperature (LT50) = −33.7 °C], and several populations maintained an extreme level of cold hardiness into late winter. Midwinter cold hardiness also varied by latitude (r = −0.65), with northern populations showing higher levels of cold hardiness. These results indicate that certain wild oakleaf hydrangea populations will be useful for introgressing novel variation into breeding programs.

Hybrid Simulation and Planning Platform for Cryosurgery with Microsoft HoloLens

Cryosurgery is a technique of growing popularity involving tissue ablation under controlled freezing. Technological advancement of devices along with surgical technique improvements have turned cryosurgery from an experimental to an established option for treating several diseases. However, cryosurgery is still limited by inaccurate planning based primarily on 2D visualization of the patient’s preoperative images. Several works have been aimed at modelling cryoablation through heat transfer simulations; however, most software applications do not meet some key requirements for clinical routine use, such as high computational speed and user-friendliness. This work aims to develop an intuitive platform for anatomical understanding and pre-operative planning by integrating the information content of radiological images and cryoprobe specifications either in a 3D virtual environment (desktop application) or in a hybrid simulator, which exploits the potential of the 3D printing and augmented reality functionalities of Microsoft HoloLens. The proposed platform was preliminarily validated for the retrospective planning/simulation of two surgical cases. Results suggest that the platform is easy and quick to learn and could be used in clinical practice to improve anatomical understanding, to make surgical planning easier than the traditional method, and to strengthen the memorization of surgical planning.

Freezing stress survival mechanisms in Vaccinium macrocarpon Ait. terminal buds

Plants’ mechanisms for surviving freezing stresses are essential adaptations that allow their existence in environments with extreme winter temperatures. Although it is known that Vaccinium macrocarpon Ait. buds can acclimate in fall and survive very cold temperatures during the winter, the mechanism for survival of these buds is not known. The main objective of this study was to determine which of the two major mechanisms of freezing stress survival, namely, deep supercooling or freeze-induced dehydration, are employed by V. macrocarpon terminal buds. In the present study, no low-temperature exotherms (LTEs) were detected by differential thermal analysis. Furthermore, a gradual reduction of relative liquid water content in the inner portions of buds during magnetic resonance imaging (MRI) scans performed between 0 and −20 °C (where no damage was detected in controlled freezing tests (CFT)) indicates these buds may not deep supercool. The higher ice nucleation activity of outer bud scales and the appearance of large voids in this structure in early winter, in conjunction with the MRI observations, are evidence supportive of a freeze-induced dehydration process. In addition, the presence of tissue browning in acclimated buds as a result of freezing stress was only observed in CFT at temperatures below −20 °C, and this damage gradually increased as test temperatures decreased and at different rates depending on the bud structure. Ours is the first study to collect multiple lines of evidence to suggest that V. macrocarpon terminal buds survive long periods of freezing stress by freeze-induced dehydration. Our results provide a framework for future studies of cold hardiness dynamics for V. macrocarpon and other woody perennial species and for the screening of breeding populations for freezing stress tolerance traits.

Practical and safe method of cryopreservation for clinical application of human adipose-derived mesenchymal stem cells without a programmable freezer or serum

BackgroundAdipose-derived mesenchymal stem cells (ADSCs) have emerged as a promising therapeutic modality for cellular therapy because of their rapid proliferation and potent cellular activity compared to conventional bone marrow-derived mesenchymal stem cells (MSCs). Cosmetic lipoaspirates provide an easily obtainable source of ADSCs. Cryopreservation facilitates their clinical application due to increased transportability and pooling of sufficient numbers of cells. However, proper cryopreservation techniques have not been established yet.MethodsWe evaluated the post-thaw viability and ADSC functions after cryopreservation with three cryoprotectants (serum containing 10% dimethylsulfoxide (DMSO), serum-free: CP-1TM, DMSO-free: SCB-DFTM) at two temperature (−80°C, −150°C) and two cell densities: (1 × 106, 7 × 106cells/mL) for up to 18 months using cryovials. After determining optimal conditions, we also tested if large quantities of ADSCs remained viable after 18 months of cryopreservation in a 100-mL cryobag. Rate-controlled freezing methods or liquid nitrogen storage were not exploited.ResultsADSCs cryopreserved in serum containing 10% DMSO or CP-1TMat −150°C and 7 × 106cells/mL were most viable (>85%) after 18 months without perturbation of MSC functions. Even suboptimal conditions (−80°C, 1 × 106cells/mL, no DMSO) assured >80% viability when stored for up to 9 months. Large quantities of ADSCs in a cryobag were properly cryopreserved.ConclusionsA programmable freezer or liquid nitrogen storage is not necessary. CP-1TMis preferable in terms of side effects. Simplified cryopreservation methods (−80°C and no DMSO) can be used for up to 9 months, resulting in reduced infusion toxicities and lower costs.

New Insights in Potato Leaf Freezing by Infrared Thermography

Infrared thermography has been widely used to study freezing processes in freezing resistant plants but hardly in freezing susceptible species. Solanum tuberosum leaves get frost killed at −3 °C and are unable to frost harden. The basic nature of frost injury to potato leaves is not clear. By employment of infrared differential thermal analysis (IDTA) in combination with viability assessment, we aimed to clarify the mechanistic relationship between ice formation and frost injury. During controlled freezing of potato leaves two distinct freezing events were detected by IDTA. During the first freezing event, the ice wave propagated via the xylem and spread out within 60 s throughout the whole leaf. When leaves were rewarmed after this freezing event, they did not show any frost injury symptoms. We suggest that this non-lethal first ice wave is restricted to the extracellular space. When leaves remained exposed after this exotherm, a second freezing event with a diffuse freezing pattern without a distinct starting point was recorded. When thawed after this second freezing event, leaves always showed frost damage suggesting intracellular freezing. The freezing behavior of potato leaves and its relation to frost damage corroborates that control of ice nucleation is a key for frost protection.