In some countries, the serif at the top is sometimes extended into a long upstroke, sometimes as long as the vertical line, which can lead to confusion with the glyph used for seven in other countries. In styles in which the digit 1 is written with a long upstroke, the digit 7 is often written with a horizontal stroke through the vertical line, to disambiguate them. Styles that do not use the long upstroke on digit 1 usually do not use the horizontal stroke through the vertical of the digit 7 either. While the shape of the character for the digit 1 has an ascender in most modern typefaces, in typefaces with text figures, the glyph usually is of x-height, as, for example, in . Many older typewriters lack a separate key for 1, using the lowercase letter l or uppercase I instead. It is possible to find cases when the uppercase J is used, though it may be for decorative purposes. In some typefaces, different glyphs are used for I and 1, but the numeral 1 resembles a small caps version of I, with parallel serifs at top and bottom, with the capital I being full-height. Mathematics
Definitions
Mathematically, 1 is:

in arithmetic (algebra) and calculus, the natural number that follows 0 and the multiplicative identity element of the integers, real numbers and complex numbers;
more generally, in algebra, the multiplicative identity (also called unity), usually of a group or a ring.Formalizations of the natural numbers have their own representations of 1.
The distal convoluted tubule cells also possess a sodium-chloride symporter on the apical side, which passively allows one sodium ion and one chloride ion to diffuse together in from the lumen (where urine is forming) into the cell interior. As sodium is pumped out of the cell by the ATPase, its intracellular concentration falls, and additional sodium begins to diffuse in from the tubule lumen as replacement. The symporter requires chloride to be transported in as well. Water passively follows to maintain isotonicity; excess chloride and potassium passively diffuse out the cell through basolateral channels into the interstitial space, and water accompanies them. The water and chloride, as well as the sodium pumped out by the ATPase, will be absorbed into the bloodstream. Metolazone and the other thiazide diuretics inhibit the function of the sodium-chloride symporter, preventing sodium and chloride, and therefore water too, from leaving the lumen to enter the tubule cell. As a result, water remains in the lumen and is excreted as urine, instead of being reabsorbed into the bloodstream. Since most of the sodium in the lumen has already been reabsorbed by the time the filtrate reaches the distal convoluted tubule, thiazide diuretics have limited effects on water balance and on electrolyte levels. Nevertheless, they can be associated with low sodium levels, volume depletion, and low blood pressure, among other adverse effects. Pharmacokinetics
Metolazone is only available in oral preparations. Approximately 65% of the amount ingested becomes available in the bloodstream.