diff --git a/examples/dicom2nifti.jl b/examples/dicom2nifti.jl
index 3826bc9..d5177d4 100644
--- a/examples/dicom2nifti.jl
+++ b/examples/dicom2nifti.jl
@@ -64,7 +64,7 @@ end
 function main()
     cmd = parse_commandline()
 
-    if cmd["axes"] == nothing
+    if cmd["axes"] === nothing
         axes = nothing
     else
         axes = uppercase(cmd["axes"])
@@ -96,7 +96,7 @@ function main()
         series_number = d[series_number_index].data[1]
 
         dicom_arr = get(dicoms, series_number, nothing)
-        if dicom_arr == nothing
+        if dicom_arr === nothing
             dicoms[series_number] = dicom_arr = {}
         end
         push!(dicom_arr, d)
@@ -146,7 +146,7 @@ function main()
         voxel_size = tuple(pixel_spacing..., slice_thickness)
 
         # Permute according to axes specified on command line
-        if axes != nothing
+        if axes !== nothing
             # Determine permutation of current volume to RAS
             ras = Array(Int, 3)
             sign = Array(Bool, 3)
diff --git a/examples/register.jl b/examples/register.jl
index dde7f2a..0bad1f2 100644
--- a/examples/register.jl
+++ b/examples/register.jl
@@ -34,25 +34,21 @@ function apply_rotation!(out, A, data)
     Csub = pointer_to_array(pointer(C), 3)
 
     ic = InterpGridCoefs(ptrs[1], InterpLinear)
-    for i = 1:size(out, 3)
+    for i in aexs(out,3), j in axes(out,2), k in aexs(out,1)
         B[3] = i
-        for j = 1:size(out, 2)
-            B[2] = j
-            for k = 1:size(out, 1)
-                B[1] = k
-                # Convert voxels in targ coords to voxels in mov coords
-                A_mul_B!(C, A, B)
+        B[2] = j
+        B[1] = k
+        # Convert voxels in targ coords to voxels in mov coords
+        A_mul_B!(C, A, B)
 
-                # Interpolate voxels in targ coords from voxels in mov
-                # coords
-                set_position(ic, BCnan, false, Csub)
-                v = interp(ic, ptrs[1])
-                if !isnan(v)
-                    out[k, j, i, 1] = mayberound(v, eltype(out))
-                    for l = 2:size(data, 4)
-                        out[k, j, i, l] = mayberound(interp(ic, ptrs[l]), eltype(out))
-                    end
-                end
+        # Interpolate voxels in targ coords from voxels in mov
+        # coords
+        set_position(ic, BCnan, false, Csub)
+        v = interp(ic, ptrs[1])
+        if !isnan(v)
+            out[k, j, i, 1] = mayberound(v, eltype(out))
+            for l = 2:size(data, 4)
+                out[k, j, i, l] = mayberound(interp(ic, ptrs[l]), eltype(out))
             end
         end
     end
diff --git a/src/NIfTI.jl b/src/NIfTI.jl
index 1427c1f..f7b0576 100644
--- a/src/NIfTI.jl
+++ b/src/NIfTI.jl
@@ -106,13 +106,13 @@ function NIVolume(
         t = T
     end
 
-    if extensions == nothing
+    if extensions === nothing
         extensions = NIfTIExtension[]
     end
 
     method2 = qfac != 0 || quatern_b != 0 || quatern_c != 0 || quatern_d != 0 || qoffset_x != 0 ||
         qoffset_y != 0 || qoffset_z != 0
-    method3 = orientation != nothing
+    method3 = orientation !== nothing
 
     if method2 && method3
         error("Orientation parameters for Method 2 and Method 3 are mutually exclusive")