Miracle-dz/UniFAR-FTUs huggingface dataset:
Self-Assembled M24L48 Polyhedra and Their Sharp Structural Switch upon Subtle Ligand Variation

Two Molecular Spheres Viruses form highly symmetrical coat structures, capsids, through the assembly of multiple lower-symmetry protein precursors. Recently, chemists have sought to emulate this process on a smaller scale, relying on the assembly of organic molecular struts and metal ions, rather than proteins. Sun et al. (p. 1144, published online 29 April; see the Perspective by Stefankiewicz and Sanders) now demonstrate that a mixture of palladium ions and V-shaped bridging ligands can self-assemble into a hollow, nearly spherical polyhedron with 24 vertices and a central diameter of 4 nanometers. The assembly process was highly sensitive to the ligand angle; a subtle average decrease generated instead a smaller 12-vertex product. A slight change in ligand geometry determines whether a 12- or 24-vertex polyhedron will form. Self-assembly is a powerful technique for the bottom-up construction of discrete, well-defined nanoscale structures. Large multicomponent systems (with more than 50 components) offer mechanistic insights into biological assembly but present daunting synthetic challenges. Here we report the self-assembly of giant M24L48 coordination spheres from 24 palladium ions (M) and 48 curved bridging ligands (L). The structure of this multicomponent system is highly sensitive to the geometry of the bent ligands. Even a slight change in the ligand bend angle critically switches the final structure observed across the entire ensemble of building blocks between M24L48 and M12L24 coordination spheres. The amplification of this small initial difference into an incommensurable difference in the resultant structures is a key mark of emergent behavior.
Acute Injuries to the Posterolateral Corner of the Knee in Children

Background: Isolated avulsion fractures of the posterolateral structures (the popliteus tendon, the lateral collateral ligament, and the popliteofibular ligament) of the knee are rare. Purpose: To describe the outcome after an isolated avulsion fracture at the femoral attachment of the posterolateral structures in skeletally immature patients and to communicate our clinical experience concerning diagnosis and treatment. Study Design: Case series; Level of evidence, 4. Methods: Six skeletally immature patients (mean age, 13.3 years; range, 12.6-13.7 years; 5 boys, 1 girl) with an avulsion fracture of the femoral attachment of the posterolateral structures were evaluated on average 5.1 years (range, 2.7-8.3 years) after the injury. Five patients were treated with open reduction and fixation of the fragment. The sixth patient was treated nonoperatively with cast immobilization. The evaluation was based on reassessment of radiographs and magnetic resonance imaging (MRI scans), registration of activity level, and examination of objective and subjective knee function. Results: The injury involved both the popliteus tendon and the lateral collateral ligament in 5 of the 6 cases. In the operated patients, the mean Lysholm knee score was 98 (range, 94-100) (0-100, with higher scores indicating a better outcome). The mean Knee injury and Osteoarthritis Outcome Score (KOOS) quality of life (QOL) was 80 (range, 50-100) (0-100, with higher scores indicating a better outcome). The range of motion and the KT-1000 arthrometer anterior laxity measurements were normal. The nonoperatively treated patient with involvement of both the popliteus tendon and the lateral collateral ligament suffered a bone bridge in the periphery of the femoral physis, causing a valgus deformity of the knee. An open wedge femoral osteotomy was performed. The Lysholm knee score was 80, and KOOS QOL was 25 at follow-up. The patient also had an extension deficit of 5° and a flexion deficit of 10°. Conclusion: An avulsion of the femoral attachment of the posterolateral structures in skeletally immature patients may involve both the popliteus tendon and the lateral collateral ligament. Open reduction and fixation of the fragment gave a satisfactory outcome.
New Opportunities for an Ancient Material

Insight into Silks Silkworms have been cultivated for thousands of years and their silk has been used to make fabrics for clothing, bed sheets, shirts, dresses, and for other applications like sutures. Spider silk is harder to harvest, and thus has not found such widespread use, but its fantastic combination of properties has made it a tempting material to study in detail. Omenetto and Kaplan (p. 528) review our understanding of silk chemistry, the limitations in being able to reconstitute silks and to generate them synthetically, and a range of applications that have been developed using silk materials. Spiders and silkworms generate silk protein fibers that embody strength and beauty. Orb webs are fascinating feats of bioengineering in nature, displaying magnificent architectures while providing essential survival utility for spiders. The unusual combination of high strength and extensibility is a characteristic unavailable to date in synthetic materials yet is attained in nature with a relatively simple protein processed from water. This biological template suggests new directions to emulate in the pursuit of new high-performance, multifunctional materials generated with a green chemistry and processing approach. These bio-inspired and high-technology materials can lead to multifunctional material platforms that integrate with living systems for medical materials and a host of other applications.
An Outlook on Microalgal Biofuels

Microalgae are considered one of the most promising feedstocks for biofuels. The productivity of these photosynthetic microorganisms in converting carbon dioxide into carbon-rich lipids, only a step or two away from biodiesel, greatly exceeds that of agricultural oleaginous crops, without competing for arable land. Worldwide, research and demonstration programs are being carried out to develop the technology needed to expand algal lipid production from a craft to a major industrial process. Although microalgae are not yet produced at large scale for bulk applications, recent advances—particularly in the methods of systems biology, genetic engineering, and biorefining—present opportunities to develop this process in a sustainable and economical way within the next 10 to 15 years.
Retention of Movement Pattern Changes After a Lower Extremity Injury Prevention Program Is Affected by Program Duration

Background: Changes in movement patterns have been repeatedly observed immediately after completing a lower extremity injury prevention program. However, it is not known if movement pattern changes are maintained after discontinuing the training program. Hypothesis: The ability to maintain movement pattern changes after training has ceased may be influenced by the program’s duration. The authors hypothesized that among individuals who completed either a 3-month or 9-month training program and who demonstrated immediate movement pattern changes, only those who completed the 9-month training program would maintain movement pattern changes after a 3-month period of no longer performing the exercises. Study Design: Cohort study; Level of evidence, 2. Methods: A total of 140 youth soccer athletes from 15 separate teams volunteered to participate. Athletes’ movement patterns were assessed using the Landing Error Scoring System (LESS) at pretest, posttest, and 3 months after ceasing the program (retention test). Eighty-four of the original 140 participants demonstrated improvements in their LESS scores between pretest and posttest (change in LESS score >0) and were included in the final analyses for this study (n = 84; 20 boys and 64 girls; mean age, 14 ± 2 years; age range, 11-17 years). Teams performed 3-month (short-duration group) and 9-month (extended-duration group) injury prevention programs. The exercises performed were identical for both groups. Teams performed the programs as part of their normal warm-up routine. Results: Although both groups improved their total LESS scores from pretest to posttest, only the extended-duration training group retained their improvements 3 months after ceasing the injury prevention program (F2,137 = 3.38; P = .04). Conclusion: Results suggest that training duration may be an important factor to consider when designing injury prevention programs that facilitate long-term changes in movement control.
Reassortment of Pandemic H1N1/2009 Influenza A Virus in Swine

Surveillance of pigs is important for tracking reassortment and emergence of influenza A viruses. The emergence of pandemic H1N1/2009 influenza demonstrated that pandemic viruses could be generated in swine. Subsequent reintroduction of H1N1/2009 to swine has occurred in multiple countries. Through systematic surveillance of influenza viruses in swine from a Hong Kong abattoir, we characterize a reassortant progeny of H1N1/2009 with swine viruses. Swine experimentally infected with this reassortant developed mild illness and transmitted infection to contact animals. Continued reassortment of H1N1/2009 with swine influenza viruses could produce variants with transmissibility and altered virulence for humans. Global systematic surveillance of influenza viruses in swine is warranted.
Patellar Tendon Tenodesis in Association With Tibial Tubercle Distalization for the Treatment of Episodic Patellar Dislocation With Patella Alta

Background: The association between patella alta and episodic patellar dislocation (EPD) has been well described, but its pathophysiology is not completely clear. Patella alta causes decreased contact between the patella and trochlea and decreased resistance to lateral translation of the patella. Additionally, increased patellar tendon length may allow pathologically increased coronal plane patellar motion. It may thus be desirable to address the length of the patellar tendon itself rather than just its insertion site. Hypothesis: Tenodesis of the patellar tendon in association with tibial tubercle distalization in patients with EPD and abnormally long patellar tendons (>52 mm) results in significant reduction in patellar tendon length, prevention of further patellar dislocation, and good knee function at long-term follow-up. Study Design: Case series; Level of evidence, 4. Methods: Twenty-seven knees in 22 patients with EPD and patella alta were treated with patellar tendon tenodesis and tibial tubercle distalization. Following tubercle distalization, the patellar tendon was tenodesed into the original location of the tibial tubercle with suture anchors. Changes in patellar tendon length and patellar height were measured radiographically. Any recurrent dislocation was documented, and patients completed an International Knee Documentation Committee (IKDC) subjective form at a mean of 9.6 years (range, 6-14 years) after surgery. Results: The mean length of the patellar tendon decreased from 56.3 ± 2.7 mm to 44.3 ± 8.6 mm (P < .0001). The Caton-Deschamps index decreased from 1.22 ± 0.17 to 0.95 ± 0.22 (P < .0001), and the Insall-Salvati ratio decreased from 1.42 ± 0.17 to 0.91 ± 0.18 (P < .0001). No patellar dislocations occurred postoperatively. The mean postoperative subjective IKDC score was 75.6 ± 9.5. Conclusion: Patellar tendon tenodesis and tibial tubercle distalization result in normalization of patellar tendon length, a stable patellofemoral joint, and good long-term knee function in patients with patella alta and EPD.
Radiocarbon-Based Chronology for Dynastic Egypt

Date with the Pharaohs Ancient Egypt dominated the Mediterranean world for several thousand years. However, the absolute chronology of this civilization has been uncertain, even though the sequence of rulers is well documented. Bronk Ramsey et al. (p. 1554; see the Perspective by Bruins) now provide a detailed radiocarbon-based record using more than 200 samples that spans much of this time and reduces uncertainties in some cases to less than 20 years. To avoid artifacts, the authors dated only short-lived plant remains from known contexts (i.e., that were associated with specific reigns). They then used the known reign lengths as a further constraint to obtain a final chronology. The final dates agree most closely with the previous older chronology but force some revisions to the timing of events in the Old Kingdom, the period in the third millennium B.C.E. when Egypt attained its first continuous peak of civilization. Many radiocarbon dates from short-lived plant remains provide a long and accurate chronology for ancient Egypt. The historical chronologies for dynastic Egypt are based on reign lengths inferred from written and archaeological evidence. These floating chronologies are linked to the absolute calendar by a few ancient astronomical observations, which remain a source of debate. We used 211 radiocarbon measurements made on samples from short-lived plants, together with a Bayesian model incorporating historical information on reign lengths, to produce a chronology for dynastic Egypt. A small offset (19 radiocarbon years older) in radiocarbon levels in the Nile Valley is probably a growing-season effect. Our radiocarbon data indicate that the New Kingdom started between 1570 and 1544 B.C.E. , and the reign of Djoser in the Old Kingdom started between 2691 and 2625 B.C.E. ; both cases are earlier than some previous historical estimates.
Histone H3 Thr-3 Phosphorylation by Haspin Positions Aurora B at Centromeres in Mitosis

Location, Location, Location Cell division is orchestrated by a complex signaling pathway that ensures the correct segregation of newly replicated chromosomes to the two daughter cells. The pathway is controlled in part by restricting the activity of critical regulators to specific subcellular locations. For example, the chromosomal passenger complex (CPC) is recruited to chromosomes during mitosis where it oversees kinetochore activity and cytokinesis (see Perspective by Musacchio). Wang et al. (p. 231, published online 12 August), Kelly et al. (p. 235, published online 12 August), and Yamagishi et al. (p. 239) now show that the phosphorylation of the chromatin protein, histone H3, acts to bring the CPC to chromosomes, thereby activating its aurora B kinase subunit. The Survivin subunit of CPC binds specifically to phosphorylated H3, with the phosphorylation at centromeres being carried out by the mitosis-specific kinase, haspin. Furthermore, Bub1 phosphorylation of histone H2A recruits shugoshin, a centromeric CPC adapter. Thus, these two histone marks in combination define the inner centromere. A critical regulator of cell division is recruited to chromosomes through the specific phosphorylation of a chromatin protein. Aurora B is a component of the chromosomal passenger complex (CPC) required for correct spindle-kinetochore attachments during chromosome segregation and for cytokinesis. The chromatin factors that recruit the CPC to centromeres are unknown, however. Here we show that phosphorylation of histone H3 threonine 3 (H3T3ph) by Haspin is necessary for CPC accumulation at centromeres and that the CPC subunit Survivin binds directly to H3T3ph. A nonbinding Survivin-D70A/D71A mutant does not support centromeric CPC concentration, and both Haspin depletion and Survivin-D70A/D71A mutation diminish centromere localization of the kinesin MCAK and the mitotic checkpoint response to taxol. Survivin-D70A/D71A mutation and microinjection of H3T3ph-specific antibody both compromise centromeric Aurora B functions but do not prevent cytokinesis. Therefore, H3T3ph generated by Haspin positions the CPC at centromeres to regulate selected targets of Aurora B during mitosis.
eNOS transfection of adipose‐derived stem cells yields bioactive nitric oxide production and improved results in vascular tissue engineering

This study evaluates the durability of a novel tissue engineered blood vessel (TEBV) created by seeding a natural vascular tissue scaffold (decellularized human saphenous vein allograft) with autologous adipose‐derived stem cells (ASC) differentiated into endothelial‐like cells. Previous work with this model revealed the graft to be thrombogenic, likely due to inadequate endothelial differentiation as evidenced by minimal production of nitric oxide (NO). To evaluate the importance of NO expression by the seeded cells, we created TEBV using autologous ASC transfected with the endothelial nitric oxide synthase (eNOS) gene to produce NO. We found that transfected ASC produced NO at levels similar to endothelial cell (EC) controls in vitro which was capable of causing vasorelaxation of aortic specimens ex vivo. TEBV (n = 5) created with NO‐producing ASC and implanted as interposition grafts within the aorta of rabbits remained patent for two months and demonstrated a non‐thrombogenic surface compared to unseeded controls (n = 5). Despite the xenograft nature of the scaffold, the TEBV structure remained well preserved in seeded grafts. In sum, this study demonstrates that upregulation of NO expression within adult stem cells differentiated towards an endothelial‐like lineage imparts a non‐thrombogenic phenotype and highlights the importance of NO production by cells to be used as endothelial cell substitutes in vascular tissue engineering applications. Copyright © 2013 John Wiley & Sons, Ltd.
c-di-AMP Secreted by Intracellular Listeria monocytogenes Activates a Host Type I Interferon Response

Bacterial (Interferon)ce Intracellular bacterial pathogens, such as Listeria monocytogenes, are detected in the cytosol of host immune cells, where they induce a host response that is often dependent on microbial secretion systems. Woodward et al. (p. 1703, published online 27 May) now show that L. monocytogenes produce and release cyclic diadenosine monophosphate into the host cytosol, which induces the production of host type I interferon. Because a number of intracellular pathogens contain the protein machinery to generate this nucleotide and also activate this same innate immune pathway, a common molecular mechanism may exist for host detection of cytosolic bacterial pathogens. Within the host cell, a small secondary signaling molecule from a pathogen triggers a pathway of innate immunity. Intracellular bacterial pathogens, such as Listeria monocytogenes, are detected in the cytosol of host immune cells. Induction of this host response is often dependent on microbial secretion systems and, in L. monocytogenes, is dependent on multidrug efflux pumps (MDRs). Using L. monocytogenes mutants that overexpressed MDRs, we identified cyclic diadenosine monophosphate (c-di-AMP) as a secreted molecule able to trigger the cytosolic host response. Overexpression of the di-adenylate cyclase, dacA (lmo2120), resulted in elevated levels of the host response during infection. c-di-AMP thus represents a putative bacterial secondary signaling molecule that triggers a cytosolic pathway of innate immunity and is predicted to be present in a wide variety of bacteria and archea.
Comparative chondrogenesis of human cell sources in 3D scaffolds

Cartilage tissue can be engineered by starting from a diversity of cell sources, including stem‐cell based and primary cell‐based platforms. Selecting an appropriate cell source for the process of cartilage tissue engineering or repair is critical and challenging, due to the variety of cell options available. In this study, cellular responses of isolated human chondrocytes, human embryonic stem cells and mesenchymal stem cells (MSCs) derived from three sources, human embryonic stem cells, bone marrow and adipose tissue, were assessed for chondrogenic potential in 3D culture. All cell sources were characterized by FACS analysis to compare expression of some surface markers. The cells were differentiated in two different biomaterial matrices, silk and chitosan scaffolds, in the presence and absence of bone morphogenetic protein 6 (BMP6), along with the standard chondrogenic differentiating factors. Embryonic stem cells‐derived MSCs showed unique characteristics, with preserved chondrogenic phenotype in both scaffolds with regard to chondrogenesis, as determined by real time RT‐PCR, histological and microscopical analyses. After 4 weeks of cultivation, embryonic stem cells‐derived MSCs were promising for chondrogenesis, particularly in the silk scaffolds with BMP6. The results suggest that cell source differences are important to consider with regard to chondrogenic outcomes, and among the variables addressed here the human embryonic stem cells‐derived MSCs were the preferred cell source. Copyright © 2009 John Wiley & Sons, Ltd.
Meniscal and Chondral Injuries Associated With Pediatric Anterior Cruciate Ligament Tears

Background: Anterior cruciate ligament (ACL) tears are commonly associated with meniscal and chondral injuries. Although lateral meniscal tears are commonly associated with acute ACL injuries, the chronically ACL-deficient knee is associated with an increased rate of medial meniscal injury. These associations have been described in the adult knee literature. Purpose: To evaluate the relationship of elapsed time from injury with the incidence of meniscal and chondral injuries noted at the time of surgical treatment for ACL tears in pediatric patients. The effect of age, gender, weight, and mechanism of injury was also evaluated. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A retrospective chart review of pediatric patients undergoing primary arthroscopic ACL reconstruction between January 2005 and January 2011 was performed. The presence of meniscal tear, chondral injury, number of days from injury to treatment, age, weight, gender, and mechanism of injury were recorded. The data were analyzed for associations between elapsed time before surgery as well as patient-specific factors with rates of meniscal and chondral injuries. Results: Three hundred seventy pediatric patients who underwent primary ACL reconstruction were included. Two hundred forty-one were treated ≤150 days (early) from injury, and 129 were treated >150 days (delayed) from injury. Ninety-one (37.8%) patients in the early treatment group and 69 (53.5%) patients in the delayed treatment group had medial meniscal tears (MMTs) (P = .014; odds ratio [OR], 1.8; 95% confidence interval [CI], 1.12-2.83). Lateral meniscal tear (LMT) rates were similar (56.0% and 57.4%) in each group. Age >15 years also influenced the presence of MMTs (P = .033; OR, 1.6; CI, 1.04-2.54). Increased patient weight was associated with an increased rate of MMTs and LMTs. Fifty-four of 170 (31.8%) patients weighing ≤65 kg and 106 of 200 (53%) weighing >65 kg had MMTs (P < .001; OR, 2.2; CI, 1.36-3.42). Eighty-two of 170 (48.2%) patients weighing ≤65 kg and 127 of 200 (63.5%) weighing >65 kg had LMTs (P < .018; OR, 1.7; CI, 1.10-2.68). The presence of chondral injury was significantly associated with the presence of meniscal tear in the same compartment of the knee. Conclusion: Pediatric patients treated >150 days after injury for ACL tears have a higher rate of MMT than those treated ≤150 days after injury. Increased age and weight are independently associated with a higher rate of MMT. Patients with ACL tears and an MMT or LMT are more likely to have a chondral injury in that particular compartment than those without meniscal tears.