Marrow Sentence Examples
This call is immediately answered by an active proliferation and steady maturing of the myclocytes in the marrow to form the polymorpho-nuclear leucocytes.
The "Marrow men" were marked by the zeal of their service and the effect of their preaching.
In a bone marrow biopsy, a slightly larger needle is used.
It is largely to researches on the bone marrow that we owe our present knowledge of the origin and the classification of the different cellular elements of the blood, both erythrocytes or red corpuscles, and the series of granular leucocytes or white corpuscles.
The healthy bone marrow reacts with remarkable rapidity to the demand for more blood cells which may be required by the organism; its reactions and variations in disease are very striking.
People who have aplastic anemia have bone marrow that just stops working right.
Whatever be the ancestral cell from which these cells spring, it is in the bone marrow that we find a differentiation into the various marrow cells from which are developed the mature corpuscles that pass from the marrow into the blood circulation.
If the demand be for the red cells owing to loss from haemorrhage or any of the anaemias, the fatty marrow is rapidly replaced by cellular elements; this is mainly an active proliferation of the nucleated red cells, and gives rise to the erythroblastic type of marrow.
Bone marrow invasion was shown in two of 14 patients on MR images which were confirmed by bone marrow aspirate.
A tiny sample of the marrow is then drawn (aspirated) into a syringe (a bone-marrow aspirate ).
AdvertisementA negative result had been reported in an adequate oral bone marrow mouse micronucleus assay.
Outcome in recipients of HLA-compatible related or unrelated bone marrow was compared to those receiving a second autograft.
Types of test There are two main types of bone marrow test - a bone marrow aspiration and a bone marrow trephine biopsy.
Brain, spleen, marrow and peripheral blood morphological research was also carried out under the same conditions of animal RF EMF irradiation.
Graft Versus Host A term used in donor bone marrow transplant.
AdvertisementThe effect of the alkaloid was also tested in an in vivo assay using BALB/c mouse bone marrow cells.
Erythropoietin is a genetically engineered preparation of the human hormone that promotes maturation of red cells in the bone marrow.
Rarely, inactivation of vitamin B12 may occur which can then interfere with folate metabolism which can result in bone marrow changes.
In myeloma, bortezomib affects the ability of myeloma cells to interact with the bone marrow microenvironment.
In the first instance this should be in the in-vivo bone marrow micronucleus assay.
AdvertisementServices include very specialist care for small babies, complex neurosurgery, and blood and marrow transplants.
Investigation showed the retroviral vector used to load a gene into bone marrow cells had inadvertently carried its DNA into a known oncogene.
Complement factor is released encouraging polymorphonuclear leukocyte release from bone marrow promoting phagocytosis, which produces heat.
For patients with bone marrow failure, it has been accepted practice to transfuse platelets where levels are very low.
Their initial hypothesis was that mesodermal progenitors are present in the marrow, but differ from hematopoietic progenitors.
AdvertisementWe have been investigating the chemoattractants involved in releasing mast cell progenitors from the bone marrow and mediating their recruitment to tissues.
Young patients with negative serology for CMV, who may be candidates for bone marrow transplantation, should receive CMV negative blood products.
The awakened sinner always has a question, the marrow of which is, " What must I do to be saved?
In the remaining cases there is evidence of exposure to some factor which is known to cause damage to bone marrow stem cells.
They include the thymus, the bone marrow and the lymph nodes (see ' lymphatic system ' ).
More than 100 printer toner cartridges are recycled each month by the Anthony Nolan Bone Marrow Trust.
Cancellous Bone Cancellous bone has large open spaces (marrow spaces) and plates of bone called trabeculae.
She needed large amounts of blood before receiving a life-saving bone marrow transplant, donated by her brother.
What can go wrong There are up to 2,000 patients waiting for a bone marrow transplant at any given time.
A Glasgow professor, the Rev. Mr Simson, was attacked for Arminianism and Socinianism as early as 1717; and the battle raged between the more severe Presbyterians - who still hankered after the Covenant, approved of an old work The Marrow of Modern Divinity (1646), and were especially convinced that preachers must be elected by the people - and the Moderates, who saw that the Covenant was an anachronism, thought conduct more important than Calvinistic convictions, and supported in the General Assembly the candidates selected by patrons, as against those chosen by the popular voice.
Bone marrow could be reconstituted from cultured brain, and glial and neurons cells were obtained from bone marrow.
New red cells are of course continually manufactured and this also takes place within the bone marrow.
There are some other cells in the marrow such as plasma cells, fibroblasts, and reticuloendothelial cells.
We previously demonstrated the selective presence of 5T2MM cells in bone marrow and spleen of diseased mice.
Bone Marrow or stem cell transplants become necessary when the bone marrow becomes diseased or damaged, preventing it from functioning normally.
They include the thymus, the bone marrow and the lymph nodes (see ' lymphatic system ').
Heterosexuals at risk of transmissible diseases are also excluded from giving bone marrow.
Marrow 's Plum is very trendy at the moment.
It affects the lymph nodes, bone marrow and the intestines.
In this stage, the animal will have infections of bone marrow and other tissue and will be considered terminally infected.
Cats in the secondary stage will often suffer repeated bone marrow infections and weakened immunity that will make them more susceptible to external and internal pathogens.
In some anemias, a bone marrow sample will be removed (bone marrow biopsy) for microscopic examination, especially to confirm iron deficiency anemia or the megaloblastic anemias.
Children or young adults with thalassemia major may require periodic hospitalization to receive blood transfusions or, in some cases, bone marrow transplants.
Treatment for aplastic anemia may involve blood transfusions and bone marrow transplantation to replace malfunctioning cells with healthy ones.
Megaloblast-A large erythroblast (a red marrow cell that synthesizes hemoglobin).
Other cells that grow fast are cells of the bone marrow that produce blood cells, cells in the stomach and intestines, and cells of the hair follicles.
Because chemotherapy affects the bone marrow, where blood cells are made, levels of these cells often drop during chemotherapy.
Low blood cell counts caused by the effect of chemotherapy on the bone marrow can lead to anemia, infections, and easy bleeding and bruising.
The body attempts to compensate by producing more blood, which is made inside the bones in the marrow.
Most of these infants received experimental treatment including transfusions before birth, early delivery, and bone marrow transplantation before birth, although the latter procedure had, as of 2004, not yet been successful.
Bone marrow transplantation-A medical procedure in which a quantity of bone marrow is extracted through a needle from a donor, and then passed into a patient to replace the patient's diseased or absent bone marrow.
Other diseases may destroy platelets outside the marrow.
If these tests indicate that platelet destruction is causing the disorder, the physician may order a bone marrow biopsy.
As the infant's bone marrow begins to produce new red cells, fetal hemoglobin begins to decrease rapidly.
It may also reappear in adults when the bone marrow is overactive, as in disorders such as pernicious anemia, multiple myeloma, and invasive (metastatic) cancer affecting bone marrow.
Chronic leukemia is a disease in which abnormal, cancerous white blood cells are made in the bone marrow.
Chronic leukemia is a cancer that starts in the blood cells made in the bone marrow.
The bone marrow makes precursor cells called blasts or stem cells, which mature into different types of blood cells.
During the bone marrow biopsy, a cylindrical piece of bone and marrow is removed.
In addition to diagnosis, bone marrow biopsy is also done during the treatment phase of the disease to see if the leukemia is responding to therapy.
Bone marrow transplantation (BMT) is in the early 2000s becoming the treatment of choice for CML because it has the possibility of curing the illness.
In BMT, the patient's diseased bone marrow is replaced with healthy marrow.
In an allogeneic bone marrow transplant, healthy marrow is taken from another person (donor) whose tissue is either the same or very closely resembles the patient's tissues.
To replace the destroyed marrow, healthy marrow from the donor is given to the patient through a needle in the vein.
The marrow remaining in the patient's body is then destroyed with high dose chemotherapy and radiation therapy.
Following that, the patient's own marrow that was frozen is thawed and given back to the patient through a needle in the vein.
This mode of bone marrow transplant is as of the early 2000s being investigated in clinical trials.
In chronic myeloid leukemia (CML), the treatment of choice is bone marrow transplantation.
In CML, if bone marrow transplantation is performed within one to three years of diagnosis, 50 to 60 percent of the patients survive three years or more.
A subsequent treatment for XHIM is bone marrow transplantation (BMT), which is also referred to as hematopoietic stem cell transplantation (HSCT).
The best source of bone marrow for transplantation is the affected child's siblings.
They will be tissue-typed to determine whether their bone marrow has the same human leukocyte antigens (HLA) as the affected child.
The closer the HLA match between a bone marrow donor and recipient, the lower the chances that the recipient's body will reject the transplanted tissue.
In addition to siblings, another choice is bone marrow from one of the parents, who shares half the affected child's HLA antigens.
With the expansion of bone marrow registries since the early 2000s, it is also possible to use bone marrow from an unrelated donor whose tissues closely match those of the affected child.
The most successful bone marrow transplants in hyper-IgM children, however, have used marrow donated by HLA-identical siblings.
However, researchers expect the outlook to improve for children in treatment in 2004, particularly those patients who are good candidates for bone marrow transplantation.
Such procedures as bone marrow or cord blood transplantation are also costly.
B cell-A type of white blood cell derived from bone marrow.
Stem cells from cord blood can be used in place of bone marrow for treating primary immunodeficiency disorders.
Human leuckocyte antigen (HLA)-A group of protein molecules located on bone marrow cells that can provoke an immune response.
A donor's and a recipient's HLA types should match as closely as possible to prevent the recipient's immune system from attacking the donor's marrow as a foreign material that does not belong in the body.
Bone marrow transplantation may correct immunodefiency in some cases.
The condition may also be associated with protein-losing enteropathy, low levels of iron in the blood serum or in the bone marrow (iron-deficiency anemia), or impaired absorption of nutrients by the intestines (malabsorption).
This type of anemia is caused by deficient erythropoiesis, the ongoing process of the bone marrow to produce healthy red blood cells (RBCs).
Iron is an essential component of the production of healthy RBCs, and iron stores must be maintained for the ongoing production of RBCs by the bone marrow.
Confirmation may also be obtained by taking a bone marrow sample (bone marrow biopsy) for microscopic examination.
If the deficiency is not treated (usually by bone marrow transplant), a person with SCID usually dies from infection before the age of two years.
In some severe cases, a bone marrow transplant or thymus transplant can be performed to correct the problem.
For most patients with SCID, bone marrow transplantation is necessary.
In this procedure, healthy bone marrow from a donor who has a similar type of tissue (usually a relative, such as a brother or sister) is removed.
The bone marrow, a substance that is found in the cavity of bones, is the factory that produces blood cells, including some of the white blood cells that make up the immune system.
The bone marrow of the person receiving the transplant is destroyed and is then replaced with marrow from the donor.
If a bone marrow transplant is not successfully performed, the child usually may not live beyond two years of age.
Chloramphenicol is not a first-choice drug because of its side effects, including interference with bone marrow production of blood cells.
B cells are produced in the bone marrow and carried to the spleen, lymph nodes, and other organs as they mature.
Macrocytic cells occur when division of RBC precursor cells in the bone marrow is impaired.
Normocytic anemia may be caused by decreased production (e.g. malignancy and other causes of bone marrow failure), increased destruction (hemolytic anemia), or blood loss.
Bone mass continues to increase rapidly, often filling in the hollow middle of the bone where the bone marrow, which produces red blood cells, is found.
When fibrous or bony tissue invades bone marrow where red blood cells are made, the individual may develop anemia.
Because of the high risk of death, this procedure is done only with the most severely affected children where a good bone marrow match can be found.
About two-thirds of children who have severe malignant infantile osteopetrosis die before age ten unless they have a successful bone marrow transplant.
The more severe form of congenital osteopetrosis is usually fatal within the first ten years of life unless successfully treated with a bone marrow transplant.
Bone marrow transplantation has been successful in a number of cases.
Severe cases have been treated by transplantation of fetal thymus tissue or bone marrow.
Reacting to the anemia, the fetal bone marrow may release immature RBCs, or erythroblasts, into the fetal peripheral circulation, causing erythroblastosis fetalis.
The baby's body tries to compensate for the anemia by releasing immature red blood cells, called erythroblasts, from the bone marrow.
Cord blood can help people who need bone marrow transplants, such as patients with leukemia, lymphoma, or genetic or immune disorders.
Like bone marrow, cord blood is rich in stem cells.
Since a bone marrow transplant requires a very close genetic match, it can be hard to match donors and recipients.
Cord blood does not have to match as closely, so it can sometimes be used when no bone marrow donor can be found.
It's also available more quickly; cord blood banks can supply a unit in about two weeks, instead of two months for bone marrow.
Visit the National Marrow Donor Program for help in finding out about hospitals near you.
That's because your hair's cell system is the second most active cell system in the body, second only to bone marrow.
Skin is living tissue that forms the largest organ in the body, while hair is non-living tissue that has the second fastest tissue growth rate in the body (the fastest is bone marrow).
Yul Kwon has been busy promoting a charity to raise awareness of the need for minority bone marrow donors.
For a bone marrow trephine, the needle is thicker.
Medical help-While you might not be able to provide a cure for your child or someone else's child, you can help through blood and bone marrow donations.
Osso Buco is made with lamb shanks and the marrow of the shanks is part of the appeal of the dish.
The marrow should be removed from the inside of the bones and placed in the kettle first.
Bones do provide calcium and rich marrow; however, some bones can pose a choking threat for your pet.
The company includes bones in the Four-Star Nutritionals Chicken Thighs canned food because of the nutritional value of bone marrow and cartilage for joint health.
This strain infects the bloodstream and attacks the lining of the digestive tract, bone marrow and cells.
A bone marrow biopsy may be done to determine what type of cells is present in the bone marrow.
Bone marrow is the tissue within bone cavities that produces blood cells.
Healthy bone marrow tissue constantly replenishes the blood supply and is essential to life.
Sometimes drugs or radiation needed to destroy cancer cells also destroys bone marrow and only replacement with healthy cells counteracts this adverse effect.
A bone marrow transplant involves removing marrow from a donor and transplanting blood-forming cells to a recipient.
While not a therapy in itself, bone marrow transplantation may allow a cancer patient to undergo aggressive therapy.
Hematologists specialize in disorders of the blood and bone marrow and are consulted in the evaluation of leukemia, lymphoma, and bone cancer.
Leukemia is a cancer that starts in the organs that make blood, namely the bone marrow and the lymph system.
The cells that make up blood are produced in the bone marrow and the lymph system.
The bone marrow is the spongy tissue found in the large bones of the body.
The bone marrow makes stem cells, which are the precursors of the different blood cells.
This uncontrolled proliferation of the immature cells in the bone marrow affects the production of the normal red blood cells and platelets as well.
Having a history of diseases that damage the bone marrow, such as aplastic anemia, or a history of cancers of the lymphatic system puts people at a high risk for developing acute leukemias.
The doctor may perform a bone marrow biopsy to confirm the diagnosis of leukemia.
During the biopsy, a cylindrical piece of bone and marrow is removed.
Once the patient shows no obvious signs of leukemia (no leukemic cells are detected in blood tests and bone marrow biopsies), the patient is said to be in remission.
Bone marrow transplantation is a process in which the patient's diseased bone marrow is replaced with healthy marrow.
There are two ways of doing a bone marrow transplant.
In an allogeneic bone marrow transplant, healthy marrow is taken from a donor whose tissue is either the same as or very closely resembles the patient's tissues.
First, the patient's bone marrow is destroyed with very high doses of chemotherapy and radiation therapy.
Healthy marrow from the donor is then given to the patient through a needle in a vein to replace the destroyed marrow.
In the second type of bone marrow transplant, called an autologous bone marrow transplant, some of the patient's own marrow is taken out and treated with a combination of anticancer drugs to kill all the abnormal cells.
The marrow remaining in the patient's body is destroyed with high-dose chemotherapy and radiation therapy.
The marrow that was frozen is then thawed and given back to the patient through a needle in a vein.
This mode of bone marrow transplant is in the early 2000s being investigated in clinical trials.
Osteomyelitis-An infection of the bone and bone marrow, usually caused by bacteria.
Bone marrow transplantation has been shown to provide a cure for severely affected children with sickle cell disease, but the procedure is not entirely without risk.
In addition, the marrow must come from a healthy matched sibling donor and only about 18 percent of children with sickle cell anemia are likely to have a matched sibling.
Aplastic anemia-A disorder in which the bone marrow greatly decreases or stops production of blood cells.
Platelets, which are also called thrombocytes, are small disk-shaped blood cells produced in the bone marrow and involved in the process of blood clotting.
High platelet counts or low platelet counts sometimes indicate disorders of the bone marrow.
The primary functions of a platelet count are to assist in the diagnosis of bleeding disorders and to monitor patients who are being treated for any disease involving bone marrow failure.
Leukemia-A cancer of the blood-forming organs (bone marrow and lymph system) characterized by an abnormal increase in the number of white blood cells in the tissues.
It occurs in polycythemia vera and other disorders in which the bone marrow produces too many platelets.
Leukemia and aplastic anemia can result in a low platelet count because of decreased production of platelets in the bone marrow.
Abnormally high platelet levels (thrombocytosis) may indicate either a benign reaction to an infection, surgery, or certain medications; or a disease like polycythemia vera, in which the bone marrow produces too many platelets too quickly.
Other studies (chest x rays, CT scan of the lungs, bone marrow biopsy) may also be done in order to see if the tumor has spread to other locations.
In rare cases, bone marrow transplantation may be used.
Under abnormal conditions these cells affect skin, bone, and the pituitary gland as well as the lungs, intestines, liver, spleen, bone marrow, and brain.
If the bone marrow is involved, anemia can result.
They have transplanted bone marrow cells into living embryos in the uteri of animals to approach congenital diseases, birth defects, and mental retardation.
Other sources of stem cells are available, however, and can be harvested from umbilical cord blood as well as from fat, bone marrow, and other adult tissue without harm to the donor.
Bone marrow transplantation is being investigated as a possible treatment.
B-cell (B lymphocyte)-A small white blood cell from bone marrow responsible for producing antibody and serving as a precursor for plasma cells.
Lymphocytic leukemia-An acute form of childhood leukemia characterized by the development of abnormal cells in the bone marrow.
T cell-A type of white blood cell that is produced in the bone marrow and matured in the thymus gland.
Bone marrow transplants are as of 2004 regarded as one of the few effective standard treatments for most types of SCID.
Up to 95 percent of children who are treated with bone marrow transplants, especially those who are treated before three months of age, survive.
Children who are treated with bone marrow transplants have a much better prognosis.
Bcell-A type of white blood cell derived from bone marrow.
Accounting for fewer than 5 percent of bone tumors in children, Ewing's sarcoma usually begins in the soft tissue (the marrow) inside bones of the leg, hips, ribs, and arms.
A complete blood count (CBC) reveals abnormalities in the blood and may indicate whether bone marrow has been affected.
For MPS I and VI, bone marrow transplantation has been attempted as a treatment option.
For those types of MPS, bone marrow transplantation has sometimes helped slow down the progression or reverse some of symptoms of the disorder in some children.
The benefits of bone marrow transplantation are more likely to be noticed when performed on children less than two years of age.
However, bone marrow transplantation is not thought to be helpful in other MPS disorders.
Availability of donors is limited, and as a result, very few bone marrow transplantations are done for MPS.
These include anemia, or breakdown of red blood cells; reduced platelets; reduced white cells; and bone marrow failure.
Heme is produced in several tissues in the body, but its primary biosynthesis sites are the liver and the bone marrow.
Heme synthesis for immature red blood cells, namely the erythroblasts and the reticulocytes, occurs in the bone marrow.
Although production is concentrated in the liver and bone marrow, heme is utilized in various capacities in virtually every tissue in the body.
Hepatoerythopoietic porphyria (HEP) affects heme biosynthesis in both the liver and the bone marrow.
The specific symptoms of each porphyria vary based on which enzyme is affected and whether that enzyme occurs in the liver or in the bone marrow.
Severely affected patients may be offered bone marrow transplantation which appears to confer long-term benefit.
Erythropoiesis-The process through which new red blood cells are created; it begins in the bone marrow.
Deep bites or bites near joints can damage joints and bones, causing inflammation of the bone and bone marrow, necrotizing fasciitis, or septic arthritis.
Bone marrow transplants may be effective for children with X-ALD if administered early in the course of the childhood form of the disease.
If the cancer appears to have spread beyond the eye, then other assessments such as a blood test, spinal tap (lumbar puncture), and/or bone marrow biopsy may be recommended.
In a bone marrow biopsy, a small amount of tissue (bone marrow) is taken from inside the hip or breast bone for examination.
The iron released from the RBCs is returned to the bone marrow to help create new cells.
Anemia due to vitamin C deficiency is a rare disorder that causes the bone marrow to manufacture abnormally small red blood cells.
It is the result of either infection or the presence of antibodies that destroy RBCs more rapidly than bone marrow can replace them.
Sometimes curable by bone marrow transplant, but potentially fatal, aplastic anemia is characterized by decreased production of red and white blood cells and platelets (disc-shaped cells that are a key component of blood coagulation).
Common underlying disorders include leukemia, drug toxicity, or aplastic anemia, all of which lead to decreased or defective production of platelets in the bone marrow.
Supportive care also includes monitoring of blood cell counts for patients using chloramphenicol, ampicillin, or other drugs that may affect production of blood cells by the bone marrow.
Bone marrow transplantation (BMT) is the only therapy that can completely cure severe malignant infantile osteopetrosis.
Deep bites or bites near joints can damage joints and bones, causing inflammation of the bone and bone marrow or septic arthritis.
If the white cells be required, as in local suppurating abscess, general septicaemia, acute pneumonia, &c., there is an active proliferation of the myelocytes to form the polymorpho-nuclear leucocytes, so that we have in this condition a leucoblastic transformation of the fatty marrow.
The cytology of bone marrow, with the technique of blood examination, is of great assistance in the diagnosis of different pathological conditions.
To replace this cellular destruction there has been a demand for reinforcements on the home centres of the polymorpho-nuclear leucocytes - the bone marrow.
It is the central nervous system, and contains within itself the elements of the brain and spinal marrow of higher forms. The neurochord tapers towards its posterior end, where it is coextensive with the notochord, but ends abruptly in front, some distance behind the tip of the snout.
The Logos is quick and powerful, and sharper than any two-edged sword, piercing even to the dividing asunder of the joints and marrow.
This was the famous Marrow of Modern Divinity, by Edward Fisher, a compendium of the opinions of leading Reformation divines on the doctrine of grace and the offer of the Gospel.
In my opinion, far superior in flavor to the marrow, although the latter obviously make better coshes.
Briefly, target molecules will be used on bone marrow stem cells in tissue culture to induce specific appropriate differentiation.
He concluded, and we agree, that that can best be done by raising awareness of bone marrow donation.
We must not lose sight of the fact, however, that there are not enough bone marrow donors, full stop.
Whether IFN-alpha is able to postpone marrow fibrosis if administered in early disease stages remains to be determined in future clinical trials.
Medial to the mental foramen, the nerves were frequently in the form of small bundles in the marrow.
The warm, slightly gelatinous marrow would slide down my throat, its strong meaty taste filling my mouth.
All of them are derived from the bone marrow but T cells undergo a process of maturation in the thymus gland.
My skin had gone taut with the sheer iciness of it, and I felt chilled through to the marrow.
Josh Eaton's Home Page A 7 year old who has had a bone marrow transplant for Philadelphia chromosome positive acute lymphoblastic leukemia.
Blood donors can also add their name to the NBS's own Bone Marrow Register - and become a lifesaver twice over this holiday.
Lived deep and dangerous and sucked the marrow out of life.
Happily, his brother Neil donated bone marrow for Lee, which was a perfect match.
We have also found a spiral fracture on what is possibly a deer bone, opened by a Neanderthal to extract the marrow.
The neck of the animal should not be disjoined during slaughtering intentionally, even the knife should not go deep into the spinal marrow.
During a transplant, healthy bone marrow will be fed into your blood stream.
With my first taste of roast bone marrow with parsley salad was born my enduring love of meat, nose to tail.
Until recently there has been little consideration as to whether artifactual positive results can also be obtained in the in-vivo bone marrow assays.
Marrow's Plum is very trendy at the moment.
That sacred communication of His flesh and blood whereby Christ transfuses into us His life, even as if it penetrated into our bones and marrow, He in the Supper attests and seals; and that not by a vain or empty sign set before us, but there He puts forth the efficacy of His Spirit whereby He fulfils what He promises.
On Boston's recommendation, Hog of Carnock reprinted The Marrow in 1718; and Boston also published an edition with notes of his own.
The Marrow was discouraged as verging on Antinomianism (1720); and in 1722 its protesting admirers were rebuked by the Assembly.
The boy was afterwards entrusted to the care of Chiron, who, to give him the strength necessary for war, fed him with the entrails of lions and the marrow of bears and wild boars.
The Marrow men put in protests, and were clearly on the way to secession from the kirk.