The cornea is the transparent front part of the eye that covers the iris and anterior chamber. The cornea, with the anterior chamber and lens, refracts light, with the cornea accounting for two-thirds of the eye's total optical power. In humans, the refractive power of the cornea is 43 dioptres; the cornea can be reshaped by surgical procedures such as LASIK. While the cornea contributes most of the eye's focusing power, its focus is fixed. Accommodation is accomplished by changing the geometry of the lens. Medical terms related to the cornea start with the prefix "kerat-" from the Greek word κέρας, horn; the cornea has unmyelinated nerve endings sensitive to touch and chemicals. Because transparency is of prime importance, the healthy cornea does not have or need blood vessels within it. Instead, oxygen dissolves in tears and diffuses throughout the cornea to keep it healthy. Nutrients are transported via diffusion from the tear fluid through the outside surface and the aqueous humour through the inside surface.
Nutrients come via neurotrophins supplied by the nerves of the cornea. In humans, the cornea has a diameter of about 11.5 mm and a thickness of 0.5–0.6 mm in the center and 0.6–0.8 mm at the periphery. Transparency, the presence of immature resident immune cells, immunologic privilege makes the cornea a special tissue; the most abundant soluble protein in mammalian cornea is albumin. The human cornea borders with the sclera via the corneal limbus. In lampreys, the cornea is an extension of the sclera, is separate from the skin above it, but in more advanced vertebrates it is always fused with the skin to form a single structure, albeit one composed of multiple layers. In fish, aquatic vertebrates in general, the cornea plays no role in focusing light, since it has the same refractive index as water; the human cornea has five layers. Corneas of other primates have five known layers; the corneas of cats, dogs and other carnivores only have four. From the anterior to posterior the layers of the human cornea are: Corneal epithelium: an exceedingly thin multicellular epithelial tissue layer of fast-growing and regenerated cells, kept moist with tears.
Irregularity or edema of the corneal epithelium disrupts the smoothness of the air/tear-film interface, the most significant component of the total refractive power of the eye, thereby reducing visual acuity. It is continuous with the conjunctival epithelium, is composed of about 6 layers of cells which are shed on the exposed layer and are regenerated by multiplication in the basal layer. Bowman's layer: when discussed in lieu of a subepithelial basement membrane, Bowman's Layer is a tough layer composed of collagen, nidogen and other HSPGs that protects the corneal stroma; when discussed as a separate entity from the subepithelial basement membrane, Bowman's Layer can be described as an acellular, condensed region of the apical stroma, composed of randomly organized yet woven collagen fibrils. These attach onto each other; this layer is eight to 14 micrometres thick and is absent or thin in non-primates. Corneal stroma: a thick, transparent middle layer, consisting of arranged collagen fibers along with sparsely distributed interconnected keratocytes, which are the cells for general repair and maintenance.
They are superimposed like book pages. The corneal stroma consists of 200 layers of type I collagen fibrils; each layer is 1.5-2.5 μm. Up to 90% of the corneal thickness is composed of stroma. There are 2 theories of how transparency in the cornea comes about: The lattice arrangements of the collagen fibrils in the stroma; the light scatter by individual fibrils is cancelled by destructive interference from the scattered light from other individual fibrils. The spacing of the neighboring collagen fibrils in the stroma must be < 200 nm for there to be transparency. Descemet's membrane: a thin acellular layer that serves as the modified basement membrane of the corneal endothelium, from which the cells are derived; this layer is composed of collagen type IV fibrils, less rigid than collagen type I fibrils, is around 5-20 μm thick, depending on the subject's age. Just anterior to Descemet's membrane, a thin and strong layer, Dua's layer, 15 microns thick and able to withstand 1.5 to 2 bars of pressure.
Corneal endothelium: a simple squamous or low cuboidal monolayer, approx 5 μm thick, of mitochondria-rich cells. These cells are responsible for regulating fluid and solute transport between the aqueous and corneal stromal compartments. Unlike the corneal epithelium, the cells of the endothelium do not regenerate. Instead, they stretch to compensate for dead cells which reduces the overall cell density of the endothelium, which affects fluid regulation. If the endothelium can no longer maintain a proper fluid balance, stromal swelling due to excess fluids and subsequent loss of transparency will occur and this may cause corneal edema and interference with the transparency of the cornea and thus impairing the image formed. Iris pigment cells deposited on the corneal end
Rabban Gamaliel II was the first person to lead the Sanhedrin as Nasi after the fall of the second temple in 70 CE. Gamliel was appointed nasi 10 years later. Gamaliel II was the son of Shimon ben Gamaliel, one of Jerusalem's foremost men in the war against the Romans, grandson of Gamaliel I. To distinguish him from the latter he is called Gamliel of Yavne. Rabban Gamliel II seemed to have settled in Kefar'Othnai in Lower Galilee, but with the outbreak of the war with Rome, he fled to Jerusalem. From there, he moved to Yavne. In Yavne, during the siege of Jerusalem, the scribes of the school of Hillel had taken refuge by permission of Vespasian, a new centre of Judaism arose under the leadership of the aged Johanan ben Zakkai, a school whose members inherited the authority of the Sanhedrin of Jerusalem. Gamaliel II became Johanan ben Zakkai's successor, rendered immense service in the strengthening and reintegration of Judaism, deprived of its former basis by the destruction of the Second Temple and by the entire loss of its political autonomy.
He put an end to the division which had arisen between the spiritual leaders of Judaism by the separation of the scribes into the two schools called after Hillel and Shammai, took care to enforce his own authority as the president of the chief legal assembly of Judaism with energy and with severity. He did this, as he himself said, not for his own honor nor for that of his family, but in order that disunion should not prevail in Israel. Gamaliel's position was recognized by the Roman government and he journeyed to Syria for the purpose of being confirmed in office by the governor. Towards the end of Domitian's reign, he went to Rome in company with the most prominent members of the school of Yavneh, in order to avert a danger threatening the Jews from the action of the emperor. Many interesting particulars have been given regarding the journey of these learned men to Rome and their sojourn there; the impression made by the capital of the world upon Gamaliel and his companions was an overpowering one, they wept when they thought of Jerusalem in ruins.
In Rome, as at home, Gamaliel had occasion to defend Judaism in polemical discussions with pagans, with professed Christians. He may have been the first to receive the title "nasi", given to raise him in public estimation and to revive the Biblical designation for the head of the nation; this title became hereditary with his descendants. Gamaliel was a controversial leader. In a dispute about fixing the calendar, Rabban Gamaliel humiliated Rabbi Joshua ben Hananiah by asking him to show up with his "stick and satchel" on the holy day which according to Rabbi Joshua's calculation was Yom Kippur. On, another dispute broke out regarding the status of the nightly prayer, he humiliated him again by asking him to stand up, to remain standing while teaching his students; this incident shocked the Rabbis, subsequently is said to have led to a rabbinic revolt against Gamaliel's leadership of the Sanhedrin. The Sanhedrin installed Rabbi Eleazar Ben Azariah as the new Nasi. After reconciling with Rabbi Joshua, Rabban Gamaliel was reinstated as Nasi, with Rabbi Eleazar serving along with him in a rotation every third week.
According to the version recorded in the Jerusalem Talmud, Rabbi Eleazar served as Av Beit Din, a viceregent. Gamaliel, showed that with him it was only a question of principle, that he had no intention of humiliating Joshua, he was implicated in the'excommunication' of his own brother-in-law, Eliezer ben Hyrcanus. His goal was to strengthen the authority of the assembly at Yavneh as well as his own authority, thus brought upon himself the suspicion of seeking his own glory. However, Gamaliel describes his motivations in this episode as in the following prayer: "Lord of the world, it is manifest and known to Thee that I have not done it for my own honor nor for that of my house, but for Thy honor, that factions may not increase in Israel." A story which confirms Gamaliel's claim to modesty is told, in which he, served his guests himself at a feast. Gamaliel's greatest achievement was ending of the opposition between the schools of Hillel and Shammai, which had survived the destruction of the Temple.
According to tradition, a voice from heaven was heard in Yavneh, declaring that although the views of both schools were justifiable in principle, in practice the views of Hillel's school are authoritative. Many of Gamaliel's decisions in religious law are connected with his stay in some place in the Holy Land. In Ecdippa the archisynagogue Scipio asked him a question which he answered by letter after his return home. There are records of Gamaliel's stay in Kfar Uthnai, in Emmaus, in Lod, in Jericho in Samaria, in Tiberias, he was on friendly terms with many non-Jews, was so warmly devoted to his slave Tavi that when Tavi died he mourned for him as for a beloved member of his own family. A friendly conversation is recorded. On the Sabbath he sat upon the benches of heathen merchants. Still and his sister, Ima Shalom, chided with the growing local Christian population mocking a certain gentile judge who had adjudicated in an inheritance case, in which Ima Shalom had made herself the make-believe claimant in the case.
When the judge at first ruled in favor of the woman, after being given a bribe by Rabban Gamaliel, he rescinde
Michael Banwell is a Canadian professional ice hockey defenseman playing for the Utah Grizzlies of the ECHL. Banwell played Division 1 NCAA hockey for the University of Maine Black Bears, where he was a finance major. In his four years there, he played 109 games, totalling 169 penalty minutes. In the 08-09 season, Banwell was tied for team leader in plus-minus rating with Gustav Nyquist. Banwell played two seasons in the American Hockey League. During the 2011–12 season, he played for the Albany Devils. Banwell started the 2012–13 season playing for the Trenton Titans, where he played 10 games before being called up to the Worcester Sharks, he split the season between the Springfield Falcons. Banwell tallied a total of 7 fights this season; the following season, Banwell signed with the Reading Royals of the ECHL. In his third professional season, playing 60 games, he tallied 3 goals and 16 assists for 19 points with the Royals, he was called up to the Bridgeport Sound Tigers during the 2013/2014 season.
Banwell signed his first contract abroad on a one-year deal with IF Björklöven of the Swedish HockeyAllsvenskan on May 9, 2015. In the 2015–16 season, he appeared in 28 games with Björklöven before agreeing to a mid-season transfer to Norwegian club, Lillehammer IK of the GET-ligaen on December 10, 2015. Unable to help Lillehammer reach the post-season, Banwell left Norway in the off-season, returning to the ECHL in signing a one-year deal with the Utah Grizzlies on August 24, 2016. Biographical information and career statistics from Eliteprospects.com, or The Internet Hockey Database