diff --git a/dask_expr/_collection.py b/dask_expr/_collection.py
index 370a3afc..b317efb9 100644
--- a/dask_expr/_collection.py
+++ b/dask_expr/_collection.py
@@ -121,6 +121,7 @@
 )
 from dask_expr._str_accessor import StringAccessor
 from dask_expr._util import (
+    PANDAS_GE_300,
     _BackendData,
     _convert_to_list,
     _get_shuffle_preferring_order,
@@ -400,7 +401,7 @@ def __getitem__(self, other):
             if (
                 self.ndim == 2
                 and is_integer_slice
-                and not is_float_dtype(self.index.dtype)
+                and (not is_float_dtype(self.index.dtype) or PANDAS_GE_300)
             ):
                 return self.iloc[other]
             else:
@@ -1577,6 +1578,10 @@ def std(
             if needs_time_conversion:
                 numeric_dd = _convert_to_numeric(self, skipna)
 
+        units = None
+        if needs_time_conversion and time_cols is not None:
+            units = [getattr(self._meta[c].array, "unit", None) for c in time_cols]
+
         if axis == 1:
             return numeric_dd.map_partitions(
                 M.std if not needs_time_conversion else _sqrt_and_convert_to_timedelta,
@@ -1598,6 +1603,8 @@ def std(
                 "time_cols": time_cols,
                 "axis": axis,
                 "dtype": getattr(meta, "dtype", None),
+                "unit": getattr(meta, "unit", None),
+                "units": units,
             }
             sqrt_func = _sqrt_and_convert_to_timedelta
         else:
diff --git a/dask_expr/_groupby.py b/dask_expr/_groupby.py
index d3c2b64d..56297bac 100644
--- a/dask_expr/_groupby.py
+++ b/dask_expr/_groupby.py
@@ -1084,6 +1084,8 @@ def npartitions(self):
 
 
 def groupby_get_group(df, *by_key, get_key=None, columns=None):
+    if PANDAS_GE_300 and is_scalar(get_key):
+        get_key = (get_key,)
     return _groupby_get_group(df, list(by_key), get_key, columns)
 
 
diff --git a/dask_expr/_indexing.py b/dask_expr/_indexing.py
index 493263d8..8fb10c19 100644
--- a/dask_expr/_indexing.py
+++ b/dask_expr/_indexing.py
@@ -87,7 +87,9 @@ def _loc(self, iindexer, cindexer):
             return self._loc(iindexer(self.obj), cindexer)
 
         if self.obj.known_divisions:
-            iindexer = self._maybe_partial_time_string(iindexer)
+            idx = self.obj.index._meta
+            unit = idx.unit if hasattr(idx, "unit") else None
+            iindexer = self._maybe_partial_time_string(iindexer, unit=unit)
 
             if isinstance(iindexer, slice):
                 return self._loc_slice(iindexer, cindexer)
@@ -133,13 +135,13 @@ def _loc_array(self, iindexer, cindexer):
         )
         return self._loc_series(iindexer_series, cindexer, check_alignment=False)
 
-    def _maybe_partial_time_string(self, iindexer):
+    def _maybe_partial_time_string(self, iindexer, unit):
         """
         Convert index-indexer for partial time string slicing
         if obj.index is DatetimeIndex / PeriodIndex
         """
         idx = meta_nonempty(self.obj._meta.index)
-        iindexer = _maybe_partial_time_string(idx, iindexer)
+        iindexer = _maybe_partial_time_string(idx, iindexer, unit)
         return iindexer
 
     def _loc_slice(self, iindexer, cindexer):