The human musculoskeletal system is highly complex mechanically. Its neural control must deal successfully with this complexity to perform the diverse, efficient, robust and usually graceful behaviors of which humans are capable. Most of those behaviors might be performed by many different subsets of its myriad possible states, so how does the nervous system decide which subset to use? One solution that has received much attention over the past 50 years would be for the nervous system to be fundamentally limited in the patterns of muscle activation that it can access, a concept known as muscle synergies or movement primitives. Another solution, based on engineering control methodology, is for the nervous system to compute the single optimal pattern of muscle activation for each task according to a cost function.  https://www.selleckchem.com/products/triptolide.html  This review points out why neither appears to be the solution used by humans. There is a third solution that is based on trial-and-error learning, recall and interpolation of sensorimotor programs that are good-enough rather than limited or optimal. The solution set acquired by an individual during the protracted development of motor skills starting in infancy forms the basis of motor habits, which are inherently low-dimensional. Such habits give rise to muscle usage patterns that are consistent with synergies but do not reflect fundamental limitations of the nervous system and can be shaped by training or disability. This habit-based strategy provides a robust substrate for the control of new musculoskeletal structures during evolution as well as for efficient learning, athletic training and rehabilitation therapy.
  In this study, we report on the synthesis, imaging, and radiosensitizing properties of ultrasmall β-NaGdF
  Yb50% nanoparticles as a multifunctional theranostic platform. The synthesized nanoparticles act as potent bimodal contrast agents with superior imaging properties compared to existing agents used for magnetic resonance imaging (MRI) and computed tomography (CT). Clonogenic assays demonstrated that these nanoparticles can act as effective radiosensitizers, provided that the nanoparticles are taken up intracellularly.
 
  Our ultrasmall β-NaGdF
  Yb50% nanoparticles demonstrate improvement in T1-weighted contrast over the standard clinical MR imaging agent Gd-DTPA and similar CT signal enhancement capabilities as commercial agent iohexol. A 2Gy dose of X-ray induced ~ 20% decrease in colony survival when C6 rat glial cells were incubated with non-targeted nanoparticles (NaGdF
  Yb50%), whereas the same X-ray dose resulted in a ~ 60% decrease in colony survival with targeted nanoparticles conjugated to folic acid (NaGdF
  Yb50%-FA). Intravenous administration of nanoparticles resulted in clearance through urine and feces within a short duration, based on the ex vivo analysis of Gd
  ions via ICP-MS.
 
  These biocompatible and in vivo clearable ultrasmall NaGdF
  Yb50% are promising candidates for further evaluation in image-guided radiotherapy applications.
 These biocompatible and in vivo clearable ultrasmall NaGdF4Yb50% are promising candidates for further evaluation in image-guided radiotherapy applications.We present a case of Koebner phenomenon induced by friction due to tightness of ear loops attached to the face mask used as protective measure against spreading COVID-19 infection.Introduction Hemophagocytic syndrome (HS) is a potentially fatal hyperinflammatory condition characterized by excessive activation of macrophages and T cells. Systemic lupus erythematosus (SLE) is an autoimmune condition that predisposes to HS. The appearance of SLE and HS is rare. Clinical case A 16-year-old male presented with fever for one month and lymphadenopathy prior to admission. During evaluation, the patient accumulated 10 points required by EULAR/ACR 2019 for classifying the condition as SLE. Hemophagocytosis was observed in the bone marrow aspirate. The diagnosis of HS secondary to SLE was concluded. Under treatment with intravenous methylprednisolone and mycophenolic acid, symptoms improved and the patient was subsequently discharged. Discussion The most typical findings of HS include fever, hepatosplenomegaly, and cytopenias, with lymphadenopathy being the least common. The characteristics of SLE and HS are very similar, making it difficult to differentiate between these two entities. Conclusion Although HS is not one of the frequent manifestations of SLE, a high suspicion of its possible association with SLE must be maintained for timely treatment.Background Cutaneous metastasis (CM) is a rare manifestation of cancer. The estimated rate of CM in ovarian cancers is about 3.5%, with a median survival of about four months after the occurrence of CM. Case report We report the case of a 65-year-old woman with stage IA G3 adenocarcinoma clear cells (WT1+,estr-) of the ovary presenting with umbilical CM after laparoscopic incisional hernia repair. Conclusion A primary tumour spread to the skin typically occurs late in the course of the disease. The overall incidence of CM from visceral neoplasia is 5.3% and 3%-4% from ovarian cancer.Intrauterine devices (IUD) are one of the most commonly used methods of contraception worldwide. The long term effect makes it desirable by most patients. The insertion of an IUD is not difficult as a technique but it involves multiple complications such as uterine perforation and migration into the abdominal cavity, urinary bladder perforation, fistula formation, bowel perforation and intra-abdominal adhesions. We present the case of a 31-year-old female patient (para=4) with a medical history of an IUD insertion during her postpartum period in February 2018. In April 2019, during her normal follow up consultation, the speculum examination did not detect any IUD strings and the abdominopelvic ultrasound showed no signs of the device inside the uterine cavity. A subsequent X-ray identified the device in a horizontal position in the pelvic region. The patient was scheduled for surgical intervention, but in the meantime she became pregnant. Decision to continue with the pregnancy was taken and surgery was delayed until the postpartum period.